1
|
Stamm CE, McFarland AP, Locke MN, Tabakh H, Tang Q, Thomason MK, Woodward JJ. RECON gene disruption enhances host resistance to enable genome-wide evaluation of intracellular pathogen fitness during infection. mBio 2024; 15:e0133224. [PMID: 38940553 PMCID: PMC11323731 DOI: 10.1128/mbio.01332-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024] Open
Abstract
Transposon sequencing (Tn-seq) is a powerful genome-wide technique to assess bacterial fitness under varying growth conditions. However, screening via Tn-seq in vivo is challenging. Dose limitations and host restrictions create bottlenecks that diminish the transposon mutant pool being screened. Here, we have developed a murine model with a disruption in Akr1c13 that renders the resulting RECON-/- mouse resistant to high-dose infection. We leveraged this model to perform a Tn-seq screen of the human pathogen Listeria monocytogenes in vivo. We identified 135 genes which were required for L. monocytogenes growth in mice including novel genes not previously identified for host survival. We identified organ-specific requirements for L. monocytogenes survival and investigated the role of the folate enzyme FolD in L. monocytogenes liver pathogenesis. A mutant lacking folD was impaired for growth in murine livers by 2.5-log10 compared to wild type and failed to spread cell-to-cell in fibroblasts. In contrast, a mutant in alsR, which encodes a transcription factor that represses an operon involved in D-allose catabolism, was attenuated in both livers and spleens of mice by 4-log10 and 3-log10, respectively, but showed modest phenotypes in in vitro models. We confirmed that dysregulation of the D-allose catabolism operon is responsible for the in vivo growth defect, as deletion of the operon in the ∆alsR background rescued virulence. By undertaking an unbiased, genome-wide screen in mice, we have identified novel fitness determinants for L. monocytogenes host infection, which highlights the utility of the RECON-/- mouse model for future screening efforts. IMPORTANCE Listeria monocytogenes is the gram-positive bacterium responsible for the food-borne disease listeriosis. Although infections with L. monocytogenes are limiting in healthy hosts, vulnerable populations, including pregnant and elderly people, can experience high rates of mortality. Thus, understanding the breadth of genetic requirements for L. monocytogenes in vivo survival will present new opportunities for treatment and prevention of listeriosis. We developed a murine model of infection using a RECON-/- mouse that is restrictive to systemic L. monocytogenes infection. We utilized this model to screen for L. monocytogenes genes required in vivo via transposon sequencing. We identified the liver-specific gene folD and a repressor, alsR, that only exhibits an in vivo growth defect. AlsR controls the expression of the D-allose operon which is a marker in diagnostic techniques to identify pathogenic Listeria. A better understanding of the role of the D-allose operon in human disease may further inform diagnostic and prevention measures.
Collapse
Affiliation(s)
- Chelsea E. Stamm
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Adelle P. McFarland
- Department of Microbiology, University of Washington, Seattle, Washington, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington, USA
| | - Melissa N. Locke
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Hannah Tabakh
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Qing Tang
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Maureen K. Thomason
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Joshua J. Woodward
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| |
Collapse
|
2
|
Freiberg JA, Reyes Ruiz VM, Gimza BD, Murdoch CC, Green ER, Curry JM, Cassat JE, Skaar EP. Restriction of arginine induces antibiotic tolerance in Staphylococcus aureus. Nat Commun 2024; 15:6734. [PMID: 39112491 PMCID: PMC11306626 DOI: 10.1038/s41467-024-51144-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 07/31/2024] [Indexed: 08/10/2024] Open
Abstract
Staphylococcus aureus is responsible for a substantial number of invasive infections globally each year. These infections are problematic because they are frequently recalcitrant to antibiotic treatment. Antibiotic tolerance, the ability of bacteria to persist despite normally lethal doses of antibiotics, contributes to antibiotic treatment failure in S. aureus infections. To understand how antibiotic tolerance is induced, S. aureus biofilms exposed to multiple anti-staphylococcal antibiotics are examined using both quantitative proteomics and transposon sequencing. These screens indicate that arginine metabolism is involved in antibiotic tolerance within a biofilm and support the hypothesis that depletion of arginine within S. aureus communities can induce antibiotic tolerance. Consistent with this hypothesis, inactivation of argH, the final gene in the arginine synthesis pathway, induces antibiotic tolerance. Arginine restriction induces antibiotic tolerance via inhibition of protein synthesis. In murine skin and bone infection models, an argH mutant has enhanced ability to survive antibiotic treatment with vancomycin, highlighting the relationship between arginine metabolism and antibiotic tolerance during S. aureus infection. Uncovering this link between arginine metabolism and antibiotic tolerance has the potential to open new therapeutic avenues targeting previously recalcitrant S. aureus infections.
Collapse
Affiliation(s)
- Jeffrey A Freiberg
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Valeria M Reyes Ruiz
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Brittney D Gimza
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Caitlin C Murdoch
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Erin R Green
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Microbiology, University of Chicago, Chicago, IL, USA
| | - Jacob M Curry
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - James E Cassat
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Eric P Skaar
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.
| |
Collapse
|
3
|
Jespersen MG, Hayes AJ, Tong SYC, Davies MR. Pangenome evaluation of gene essentiality in Streptococcus pyogenes. Microbiol Spectr 2024; 12:e0324023. [PMID: 39012116 PMCID: PMC11323703 DOI: 10.1128/spectrum.03240-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 06/23/2024] [Indexed: 07/17/2024] Open
Abstract
Bacterial species often consist of strains with variable gene content, collectively referred to as the pangenome. Variations in the genetic makeup of strains can alter bacterial physiology and fitness. To define biologically relevant genes of a genome, genome-wide transposon mutant libraries have been used to identify genes essential for survival or virulence in a given strain. Such phenotypic studies have been conducted in four different genotypes of the human pathogen Streptococcus pyogenes, yet challenges exist in comparing results across studies conducted in different genetic backgrounds and conditions. To advance genotype to phenotype inferences across different S. pyogenes strains, we built a pangenome database of 249 S. pyogenes reference genomes. We systematically re-analyzed publicly available transposon sequencing datasets from S. pyogenes using a transposon sequencing-specific analysis pipeline, Transit. Across four genetic backgrounds and nine phenotypic conditions, 355 genes were essential for survival, corresponding to ~24% of the core genome. Clusters of Orthologous Genes (COG) categories related to coenzyme and lipid transport and growth functions were overrepresented as essential. Finally, essential operons across S. pyogenes genotypes were defined, with an increased number of essential operons detected under in vivo conditions. This study provides an extendible database to which new studies can be added, and a searchable html-based resource to direct future investigations into S. pyogenes biology.IMPORTANCEStreptococcus pyogenes is a human-adapted pathogen occupying restricted ecological niches. Understanding the essentiality of genes across different strains and experimental conditions is important to direct research questions and efforts to prevent the large burden of disease caused by S. pyogenes. To this end we systematically reanalyzed transposon sequencing studies in S. pyogenes using transposon sequencing-specific methods, integrating them into an extendible meta-analysis framework. This provides a repository of gene essentiality in S. pyogenes which was used to highlight specific genes of interest and for the community to guide future phenotypic studies.
Collapse
Affiliation(s)
- Magnus G. Jespersen
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Andrew J. Hayes
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Steven Y. C. Tong
- Department of Infectious Diseases, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Victorian Infectious Diseases Service, The Royal Melbourne Hospital, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Mark R. Davies
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| |
Collapse
|
4
|
Chand P, Mendum TA, Butler RE, Hingley-Wilson SM, Stewart GR. Identification of gene targets that potentiate the action of rifampicin on Mycobacterium bovis BCG. MICROBIOLOGY (READING, ENGLAND) 2024; 170. [PMID: 39150447 PMCID: PMC11329110 DOI: 10.1099/mic.0.001488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Tuberculosis (TB) caused by bacteria of the Mycobacterium tuberculosis complex remains one of the most important infectious diseases of mankind. Rifampicin is a first line drug used in multi-drug treatment of TB, however, the necessary duration of treatment with these drugs is long and development of resistance is an increasing impediment to treatment programmes. As a result, there is a requirement for research and development of new TB drugs, which can form the basis of new drug combinations, either due to their own anti-mycobacterial activity or by augmenting the activity of existing drugs such as rifampicin. This study describes a TnSeq analysis to identify mutants with enhanced sensitivity to sub-minimum inhibitory concentrations (MIC) of rifampicin. The rifampicin-sensitive mutants were disrupted in genes of a variety of functions and the majority fitted into three thematic groups: firstly, genes that were involved in DNA/RNA metabolism, secondly, genes involved in sensing and regulating mycobacterial cellular systems, and thirdly, genes involved in the synthesis and maintenance of the cell wall. Selection at two concentrations of rifampicin (1/250 and 1/62 MIC) demonstrated a dose response for mutants with statistically significant sensitivity to rifampicin. The dataset reveals mechanisms of how mycobacteria are innately tolerant to and initiate an adaptive response to rifampicin; providing putative targets for the development of adjunctive therapies that potentiate the action of rifampicin.
Collapse
Affiliation(s)
- Pooja Chand
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH United Kingdom
| | - Tom A Mendum
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH United Kingdom
| | - Rachel E Butler
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH United Kingdom
| | - Suzanne M Hingley-Wilson
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH United Kingdom
| | - Graham R Stewart
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH United Kingdom
| |
Collapse
|
5
|
Akbari MS, Joyce LR, Spencer BL, McIver KS, Doran KS. Identification of Glyoxalase A in Group B Streptococcus and its contribution to methylglyoxal tolerance and virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.30.605887. [PMID: 39131367 PMCID: PMC11312555 DOI: 10.1101/2024.07.30.605887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Group B Streptococcus (GBS) is a Gram-positive pathobiont that commonly colonizes the gastrointestinal and lower female genital tracts but can cause sepsis and pneumonia in newborns and is a leading cause of neonatal meningitis. Despite the resulting disease severity, the pathogenesis of GBS is not completely understood, especially during the early phases of infection. To investigate GBS factors necessary for blood stream survival, we performed a transposon (Tn) mutant screen in our bacteremia infection model using a GBS mariner transposon mutant library previously developed by our group. We identified significantly underrepresented mutations in 628 genes that contribute to survival in the blood, including those encoding known virulence factors such as capsule, the β-hemolysin, and inorganic metal ion transport systems. Most of the underrepresented genes have not been previously characterized or studied in GBS, including gloA and gloB, which are homologs for genes involved in methylglyoxal (MG) detoxification. MG is a byproduct of glycolysis and a highly reactive toxic aldehyde that is elevated in immune cells during infection. Here, we observed MG sensitivity across multiple GBS isolates and confirm that gloA contributes to MG tolerance and invasive GBS infection. We show specifically that gloA contributes to GBS survival in the presence of neutrophils and depleting neutrophils in mice abrogates the decreased survival and infection of the gloA mutant. The requirement of the glyoxalase pathway during GBS infection suggests that MG detoxification is important for bacterial survival during host-pathogen interactions.
Collapse
Affiliation(s)
- Madeline S. Akbari
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| | - Luke R. Joyce
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| | - Brady L. Spencer
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| | - Kevin S. McIver
- Cell Biology and Molecular Genetics, Maryland Pathogen Research Institute, University of Maryland, College Park, Maryland, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado USA
| |
Collapse
|
6
|
Miller AH, Marks F, Chan L, Botella H, Schnappinger D, Ehrt S. Interruption of mycothiol synthesis and intracellular redox status impact iron-regulated reporter activation in Mycobacterium smegmatis. Microbiol Spectr 2024; 12:e0048724. [PMID: 38860795 PMCID: PMC11218476 DOI: 10.1128/spectrum.00487-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 05/04/2024] [Indexed: 06/12/2024] Open
Abstract
Iron scavenging is required for full virulence of mycobacterial pathogens. During infection, the host immune response restricts mycobacterial access to iron, which is essential for bacterial respiration and DNA synthesis. The Mycobacterium tuberculosis iron-dependent regulator (IdeR) responds to changes in iron accessibility by repressing iron-uptake genes when iron is available. In contrast, iron-uptake gene transcription is induced when iron is depleted. The ideR gene is essential in M. tuberculosis and is required for bacterial growth. To further study how iron regulates transcription, wee developed an iron responsive reporter system that relies on an IdeR-regulated promoter to drive Cre and loxP mediated recombination in Mycobacterium smegmatis. Recombination leads to the expression of an antibiotic resistance gene so that mutations that activate the IdeR-regulated promoter can be selected. A transposon library in the background of this reporter system was exposed to media containing iron and hemin, and this resulted in the selection of mutants in the antioxidant mycothiol synthesis pathway. We validated that inactivation of the mycothiol synthesis gene mshA results in increased recombination and increased IdeR-regulated promoter activity in the reporter system. Further, we show that vitamin C, which has been shown to oxidize iron through the Fenton reaction, can decrease promoter activity in the mshA mutant. We conclude that the intracellular redox state balanced by mycothiol can alter IdeR activity in the presence of iron.IMPORTANCEMycobacterium smegmatis is a tractable organism to study mycobacterial gene regulation. We used M. smegmatis to construct a novel recombination-based reporter system that allows for the selection of mutations that deregulate a promoter of interest. Transposon mutagenesis and insertion sequencing (TnSeq) in the recombination reporter strain identified genes that impact iron regulated promoter activity in mycobacteria. We found that the mycothiol synthesis gene mshA is required for IdeR mediated transcriptional regulation by maintaining intracellular redox balance. By affecting the oxidative state of the intracellular environment, mycothiol can modulate iron-dependent transcriptional activity. Taken more broadly, this novel reporter system can be used in combination with transposon mutagenesis to identify genes that are required by Mycobacterium tuberculosis to overcome temporary or local changes in iron availability during infection.
Collapse
Affiliation(s)
- Alexandra H Miller
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
- Immunology and Microbial Pathogenesis Graduate Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York, USA
| | - Frances Marks
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
- Biochemistry and Structural Biology, Cell and Developmental Biology, and Molecular Biology Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York, USA
| | - Luming Chan
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Helene Botella
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
- Immunology and Microbial Pathogenesis Graduate Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, New York, USA
| |
Collapse
|
7
|
Torres M, Paszti S, Eberl L. Shedding light on bacteria-host interactions with the aid of TnSeq approaches. mBio 2024; 15:e0039024. [PMID: 38722161 PMCID: PMC11237515 DOI: 10.1128/mbio.00390-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024] Open
Abstract
Bacteria are highly adaptable and grow in diverse niches, where they often interact with eukaryotic organisms. These interactions with different hosts span the entire spectrum from symbiosis to pathogenicity and thus determine the lifestyle of the bacterium. Knowledge of the genetic determinants involved in animal and plant host colonization by pathogenic and mutualistic bacteria is not only crucial to discover new drug targets for disease management but also for developing novel biostimulant strategies. In the last decades, significant progress in genome-wide high-throughput technologies such as transposon insertion sequencing has led to the identification of pathways that enable efficient host colonization. However, the extent to which similar genes play a role in this process in different bacteria is yet unclear. This review highlights the commonalities and specificities of bacterial determinants important for bacteria-host interaction.
Collapse
Affiliation(s)
- Marta Torres
- Department of Plant and Microbial Biology, University of Zurich, Zürich, Switzerland
| | - Sarah Paszti
- Department of Plant and Microbial Biology, University of Zurich, Zürich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zürich, Switzerland
| |
Collapse
|
8
|
Zhang P, Zhang B, Ji Y, Jiao J, Zhang Z, Tian C. Cofitness network connectivity determines a fuzzy essential zone in open bacterial pangenome. MLIFE 2024; 3:277-290. [PMID: 38948139 PMCID: PMC11211677 DOI: 10.1002/mlf2.12132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 04/20/2024] [Accepted: 04/24/2024] [Indexed: 07/02/2024]
Abstract
Most in silico evolutionary studies commonly assumed that core genes are essential for cellular function, while accessory genes are dispensable, particularly in nutrient-rich environments. However, this assumption is seldom tested genetically within the pangenome context. In this study, we conducted a robust pangenomic Tn-seq analysis of fitness genes in a nutrient-rich medium for Sinorhizobium strains with a canonical open pangenome. To evaluate the robustness of fitness category assignment, Tn-seq data for three independent mutant libraries per strain were analyzed by three methods, which indicates that the Hidden Markov Model (HMM)-based method is most robust to variations between mutant libraries and not sensitive to data size, outperforming the Bayesian and Monte Carlo simulation-based methods. Consequently, the HMM method was used to classify the fitness category. Fitness genes, categorized as essential (ES), advantage (GA), and disadvantage (GD) genes for growth, are enriched in core genes, while nonessential genes (NE) are over-represented in accessory genes. Accessory ES/GA genes showed a lower fitness effect than core ES/GA genes. Connectivity degrees in the cofitness network decrease in the order of ES, GD, and GA/NE. In addition to accessory genes, 1599 out of 3284 core genes display differential essentiality across test strains. Within the pangenome core, both shared quasi-essential (ES and GA) and strain-dependent fitness genes are enriched in similar functional categories. Our analysis demonstrates a considerable fuzzy essential zone determined by cofitness connectivity degrees in Sinorhizobium pangenome and highlights the power of the cofitness network in understanding the genetic basis of ever-increasing prokaryotic pangenome data.
Collapse
Affiliation(s)
- Pan Zhang
- State Key Laboratory of Plant Environmental Resilience, and College of Biological SciencesChina Agricultural UniversityBeijingChina
- MOA Key Laboratory of Soil Microbiology, and Rhizobium Research CenterChina Agricultural UniversityBeijingChina
- Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenChina
| | - Biliang Zhang
- MOA Key Laboratory of Soil Microbiology, and Rhizobium Research CenterChina Agricultural UniversityBeijingChina
- State Key Laboratory of Livestock and Poultry Biotechnology Breeding, and College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Yuan‐Yuan Ji
- State Key Laboratory of Plant Environmental Resilience, and College of Biological SciencesChina Agricultural UniversityBeijingChina
- MOA Key Laboratory of Soil Microbiology, and Rhizobium Research CenterChina Agricultural UniversityBeijingChina
| | - Jian Jiao
- State Key Laboratory of Plant Environmental Resilience, and College of Biological SciencesChina Agricultural UniversityBeijingChina
- MOA Key Laboratory of Soil Microbiology, and Rhizobium Research CenterChina Agricultural UniversityBeijingChina
| | - Ziding Zhang
- State Key Laboratory of Livestock and Poultry Biotechnology Breeding, and College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Chang‐Fu Tian
- State Key Laboratory of Plant Environmental Resilience, and College of Biological SciencesChina Agricultural UniversityBeijingChina
- MOA Key Laboratory of Soil Microbiology, and Rhizobium Research CenterChina Agricultural UniversityBeijingChina
| |
Collapse
|
9
|
Qu D, Ge P, Botella L, Park SW, Lee HN, Thornton N, Bean JM, Krieger IV, Sacchettini JC, Ehrt S, Aldrich CC, Schnappinger D. Mycobacterial biotin synthases require an auxiliary protein to convert dethiobiotin into biotin. Nat Commun 2024; 15:4161. [PMID: 38755122 PMCID: PMC11099021 DOI: 10.1038/s41467-024-48448-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 04/24/2024] [Indexed: 05/18/2024] Open
Abstract
Lipid biosynthesis in the pathogen Mycobacterium tuberculosis depends on biotin for posttranslational modification of key enzymes. However, the mycobacterial biotin synthetic pathway is not fully understood. Here, we show that rv1590, a gene of previously unknown function, is required by M. tuberculosis to synthesize biotin. Chemical-generic interaction experiments mapped the function of rv1590 to the conversion of dethiobiotin to biotin, which is catalyzed by biotin synthases (BioB). Biochemical studies confirmed that in contrast to BioB of Escherichia coli, BioB of M. tuberculosis requires Rv1590 (which we named "biotin synthase auxiliary protein" or BsaP), for activity. We found homologs of bsaP associated with bioB in many actinobacterial genomes, and confirmed that BioB of Mycobacterium smegmatis also requires BsaP. Structural comparisons of BsaP-associated biotin synthases with BsaP-independent biotin synthases suggest that the need for BsaP is determined by the [2Fe-2S] cluster that inserts sulfur into dethiobiotin. Our findings open new opportunities to seek BioB inhibitors to treat infections with M. tuberculosis and other pathogens.
Collapse
Affiliation(s)
- Di Qu
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Peng Ge
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ha-Na Lee
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Natalie Thornton
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - James M Bean
- Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Inna V Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - James C Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA.
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
10
|
Hamami E, Huo W, Hernandez-Bird J, Castaneda A, Bai J, Syal S, Ortiz-Marquez JC, van Opijnen T, Geisinger E, Isberg RR. Identification of Determinants that Allow Maintenance of High-Level Fluoroquinolone Resistance in Acinetobacter baumannii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.03.560562. [PMID: 38645180 PMCID: PMC11030222 DOI: 10.1101/2023.10.03.560562] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Acinetobacter baumannii is associated with multidrug resistant (MDR) infections in healthcare settings, with fluoroquinolones such as ciprofloxacin being currently ineffective. Clinical isolates largely harbor mutations in the GyrA and TopoIV fluoroquinolone targets, as well as mutations that increase expression of drug resistance-nodulation-division (RND) efflux pumps. Factors critical for maintaining fitness levels of pump overproducers are uncharacterized despite their prevalence in clinical isolates. We here identify proteins that contribute to the fitness of FQR strains overexpressing three known RND systems using high-density insertion mutagenesis. Overproduction of the AdeFGH efflux pump caused hypersensitization to defects in outer membrane homeostatic regulation, including lesions that reduced LOS biosynthesis and blocked production of the major A. baumannii porin. In contrast, AdeAB pump overproduction, which does not affect the outer membrane pump component, was relatively tolerant to loss of these functions, consistent with outer membrane protein overproduction being the primary disruptive component. Surprisingly, overproduction of proton-transporting efflux pumps had little impact on cytosolic pH, consistent with a compensatory response to pump activity. The most striking transcriptional changes were associated with AdeFGH pump overproduction, resulting in activation of the phenylacetate (PAA) degradation regulon. Disruption of the PAA pathway resulted in cytosolic acidification and defective expression of genes involved in protection from peroxide stress. These results indicate that the RND outer membrane protein overproduction is compensated by cytoplasmic buffering and maintenance of outer membrane integrity in A. baumannii to facilitate fitness of FQR isolates.
Collapse
Affiliation(s)
- Efrat Hamami
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Wenwen Huo
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Juan Hernandez-Bird
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | | | - Jinna Bai
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Sapna Syal
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Juan C Ortiz-Marquez
- Department of Biology, Boston College, Chestnut Hill, MA 02135 USA
- Innovation Laboratory, Broad Institute, Cambridge, MA 02412, USA
| | - Tim van Opijnen
- Innovation Laboratory, Broad Institute, Cambridge, MA 02412, USA
| | - Edward Geisinger
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| |
Collapse
|
11
|
Miravet-Verde S, Mazzolini R, Segura-Morales C, Broto A, Lluch-Senar M, Serrano L. ProTInSeq: transposon insertion tracking by ultra-deep DNA sequencing to identify translated large and small ORFs. Nat Commun 2024; 15:2091. [PMID: 38453908 PMCID: PMC10920889 DOI: 10.1038/s41467-024-46112-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 02/14/2024] [Indexed: 03/09/2024] Open
Abstract
Identifying open reading frames (ORFs) being translated is not a trivial task. ProTInSeq is a technique designed to characterize proteomes by sequencing transposon insertions engineered to express a selection marker when they occur in-frame within a protein-coding gene. In the bacterium Mycoplasma pneumoniae, ProTInSeq identifies 83% of its annotated proteins, along with 5 proteins and 153 small ORF-encoded proteins (SEPs; ≤100 aa) that were not previously annotated. Moreover, ProTInSeq can be utilized for detecting translational noise, as well as for relative quantification and transmembrane topology estimation of fitness and non-essential proteins. By integrating various identification approaches, the number of initially annotated SEPs in this bacterium increases from 27 to 329, with a quarter of them predicted to possess antimicrobial potential. Herein, we describe a methodology complementary to Ribo-Seq and mass spectroscopy that can identify SEPs while providing other insights in a proteome with a flexible and cost-effective DNA ultra-deep sequencing approach.
Collapse
Affiliation(s)
- Samuel Miravet-Verde
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003, Barcelona, Spain.
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zurich, Zurich, Switzerland.
| | | | - Carolina Segura-Morales
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003, Barcelona, Spain
| | - Alicia Broto
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003, Barcelona, Spain
| | - Maria Lluch-Senar
- Pulmobiotics, Dr Aiguader 88, 08003, Barcelona, Spain.
- Institute of Biotechnology and Biomedicine "Vicent Villar Palasi" (IBB), Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Luis Serrano
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, 08003, Barcelona, Spain.
- Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- ICREA, Pg. Lluis Companys 23, 08010, Barcelona, Spain.
| |
Collapse
|
12
|
Fiebig A, Schnizlein MK, Pena-Rivera S, Trigodet F, Dubey AA, Hennessy MK, Basu A, Pott S, Dalal S, Rubin D, Sogin ML, Eren AM, Chang EB, Crosson S. Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient. mBio 2024; 15:e0283023. [PMID: 38063424 PMCID: PMC10790697 DOI: 10.1128/mbio.02830-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 12/19/2023] Open
Abstract
IMPORTANCE The Gram-negative bacterium Bacteroides fragilis is a common member of the human gut microbiota that colonizes multiple host niches and can influence human physiology through a variety of mechanisms. Identification of genes that enable B. fragilis to grow across a range of host environments has been impeded in part by the relatively limited genetic tractability of this species. We have developed a high-throughput genetic resource for a B. fragilis strain isolated from a UC pouchitis patient. Bile acids limit microbial growth and are altered in abundance in UC pouches, where B. fragilis often blooms. Using this resource, we uncovered pathways and processes that impact B. fragilis fitness in bile and that may contribute to population expansions during bouts of gut inflammation.
Collapse
Affiliation(s)
- Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Matthew K. Schnizlein
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Selymar Pena-Rivera
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Florian Trigodet
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Abhishek Anil Dubey
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Miette K. Hennessy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Anindita Basu
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sebastian Pott
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sushila Dalal
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - David Rubin
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | | | - A. Murat Eren
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Eugene B. Chang
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| |
Collapse
|
13
|
Wang Y, Fu H, Shi XJ, Zhao GP, Lyu LD. Genome-wide screen reveals cellular functions that counteract rifampicin lethality in Escherichia coli. Microbiol Spectr 2024; 12:e0289523. [PMID: 38054714 PMCID: PMC10782999 DOI: 10.1128/spectrum.02895-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Rifamycins are a group of antibiotics with a wide antibacterial spectrum. Although the binding target of rifamycin has been well characterized, the mechanisms underlying the discrepant killing efficacy between gram-negative and gram-positive bacteria remain poorly understood. Using a high-throughput screen combined with targeted gene knockouts in the gram-negative model organism Escherichia coli, we established that rifampicin efficacy is strongly dependent on several cellular pathways, including iron acquisition, DNA repair, aerobic respiration, and carbon metabolism. In addition, we provide evidence that these pathways modulate rifampicin efficacy in a manner distinct from redox-related killing. Our findings provide insights into the mechanism of rifamycin efficacy and may aid in the development of new antimicrobial adjuvants.
Collapse
Affiliation(s)
- Yu Wang
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/National Health Commission, School of Basic Medical Sciences and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Han Fu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/National Health Commission, School of Basic Medical Sciences and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
- CAS Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiao-Jie Shi
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/National Health Commission, School of Basic Medical Sciences and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Guo-Ping Zhao
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/National Health Commission, School of Basic Medical Sciences and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
- CAS Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
| | - Liang-Dong Lyu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/National Health Commission, School of Basic Medical Sciences and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Tuberculosis, Shanghai Clinical Research Center for Infectious Disease (Tuberculosis), Shanghai Pulmonary Hospital, Shanghai, China
| |
Collapse
|
14
|
Hamami E, Huo W, Neal K, Neisewander I, Geisinger E, Isberg RR. Identification of essential genes that support fitness of Acinetobacter baumannii efflux pump overproducers in the presence of fluoroquinolone. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.04.574119. [PMID: 38260615 PMCID: PMC10802289 DOI: 10.1101/2024.01.04.574119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Acinetobacter baumannii is a nosocomial pathogen often associated with multidrug resistance (MDR) infections. Fluoroquinolone resistance (FQR) due to drug target site mutations and elevated expression of RND drug transporters is common among clinical isolates. We describe here a CRISPRi platform that identifies hypomorphic mutations that preferentially altered drug sensitivity in RND pump overproducers. An sgRNA library against essential genes of A. baumannii was constructed with single and double nucleotide mutations that produced titratable knockdown efficiencies and introduced into multiple strain backgrounds. Other than nusG depletions, there were few candidates in the absence of drug treatment that showed lowered fitness specifically in strains overexpressing clinically relevant RND efflux pumps AdeAB, AdeIJK, or AdeFGH. In the presence of ciprofloxacin, the hypomorphs causing hypersensitivity were predicted to result in outer membrane dysfunction, to which the AdeFGH overproducer appeared particularly sensitive. Depletions of either the outer membrane assembly BAM complex, LOS biogenesis proteins, or Lpt proteins involved in LOS transport to the outer membrane caused drug hypersensitivity in at least two of the three pump overproducers. On the other hand, depletions of translation-associated proteins, as well as components of the proton-pumping ATP synthase pump resulted in fitness benefits for at least two pump-overproducing strains in the presence of the drug. Therefore, pump overproduction exacerbated stress caused by defective outer membrane integrity, while the efficacy of drug resistance in efflux overproducers was enhanced by slowed translation or defects in ATP synthesis linked to the control of proton movement across the bacterial membrane.
Collapse
Affiliation(s)
- Efrat Hamami
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Wenwen Huo
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Katherine Neal
- Department of Biochemistry, Curry College, Milton, MA, USA
| | - Isabelle Neisewander
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Edward Geisinger
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
- Department of Biology, Northeastern University, Boston, MA, 02115, USA
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| |
Collapse
|
15
|
Eskandarian HA, Chen YX, Toniolo C, Belardinelli JM, Palcekova Z, Hom L, Ashby PD, Fantner GE, Jackson M, McKinney JD, Javid B. Mechanical morphotype switching as an adaptive response in mycobacteria. SCIENCE ADVANCES 2024; 10:eadh7957. [PMID: 38170768 PMCID: PMC10776010 DOI: 10.1126/sciadv.adh7957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
Invading microbes face a myriad of cidal mechanisms of phagocytes that inflict physical damage to microbial structures. How intracellular bacterial pathogens adapt to these stresses is not fully understood. Here, we report the discovery of a virulence mechanism by which changes to the mechanical stiffness of the mycobacterial cell surface confer refraction to killing during infection. Long-term time-lapse atomic force microscopy was used to reveal a process of "mechanical morphotype switching" in mycobacteria exposed to host intracellular stress. A "soft" mechanical morphotype switch enhances tolerance to intracellular macrophage stress, including cathelicidin. Both pharmacologic treatment, with bedaquiline, and a genetic mutant lacking uvrA modified the basal mechanical state of mycobacteria into a soft mechanical morphotype, enhancing survival in macrophages. Our study proposes microbial cell mechanical adaptation as a critical axis for surviving host-mediated stressors.
Collapse
Affiliation(s)
- Haig Alexander Eskandarian
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yu-Xiang Chen
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Chiara Toniolo
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Juan M. Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Zuzana Palcekova
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Lesley Hom
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Paul D. Ashby
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Georg E. Fantner
- School of Engineering, Swiss Federal Institute of Technology (EPFL), 1015 Lausanne, Switzerland
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - John D. McKinney
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Babak Javid
- Division of Experimental Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| |
Collapse
|
16
|
Jouan R, Lextrait G, Lachat J, Yokota A, Cossard R, Naquin D, Timchenko T, Kikuchi Y, Ohbayashi T, Mergaert P. Transposon sequencing reveals the essential gene set and genes enabling gut symbiosis in the insect symbiont Caballeronia insecticola. ISME COMMUNICATIONS 2024; 4:ycad001. [PMID: 38282642 PMCID: PMC10809759 DOI: 10.1093/ismeco/ycad001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/10/2023] [Accepted: 11/03/2023] [Indexed: 01/30/2024]
Abstract
Caballeronia insecticola is a bacterium belonging to the Burkholderia genus sensu lato, which is able to colonize multiple environments like soils and the gut of the bean bug Riptortus pedestris. We constructed a saturated Himar1 mariner transposon library and revealed by transposon-sequencing that 498 protein-coding genes constitute the essential genome of Caballeronia insecticola for growth in free-living conditions. By comparing essential gene sets of Caballeronia insecticola and seven related Burkholderia s.l. strains, only 120 common genes were identified, indicating that a large part of the essential genome is strain-specific. In order to reproduce specific nutritional conditions that are present in the gut of Riptortus pedestris, we grew the mutant library in minimal media supplemented with candidate gut nutrients and identified several condition-dependent fitness-defect genes by transposon-sequencing. To validate the robustness of the approach, insertion mutants in six fitness genes were constructed and their growth deficiency in media supplemented with the corresponding nutrient was confirmed. The mutants were further tested for their efficiency in Riptortus pedestris gut colonization, confirming that gluconeogenic carbon sources, taurine and inositol, are nutrients consumed by the symbiont in the gut. Thus, our study provides insights about specific contributions provided by the insect host to the bacterial symbiont.
Collapse
Grants
- JSPS Research Fellowship for Young Scientists, Japan
- Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan
- Ministry of Higher Education, Research, and Innovation, France
- CNRS International Research Project, France
- JSPS-CNRS Bilateral Open Partnership Joint Research Project, France-Japan
- Agence Nationale de la Recherche, France
- Saclay Plant Sciences-SPS
Collapse
Affiliation(s)
- Romain Jouan
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Gaëlle Lextrait
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Joy Lachat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Aya Yokota
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Raynald Cossard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Tatiana Timchenko
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, Sapporo 062-8517, Japan
| | - Tsubasa Ohbayashi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba 305-8604, Japan
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| |
Collapse
|
17
|
Chen X, Alakavuklar MA, Fiebig A, Crosson S. Cross-regulation in a three-component cell envelope stress signaling system of Brucella. mBio 2023; 14:e0238723. [PMID: 38032291 PMCID: PMC10746171 DOI: 10.1128/mbio.02387-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE As intracellular pathogens, Brucella must contend with a variety of host-derived stressors when infecting a host cell. The inner membrane, cell wall, and outer membrane, i.e. the cell envelope, of Brucella provide a critical barrier to host assault. A conserved regulatory mechanism known as two-component signaling (TCS) commonly controls transcription of genes that determine the structure and biochemical composition of the cell envelope during stress. We report the identification of previously uncharacterized TCS genes that determine Brucella ovis fitness in the presence of cell envelope disruptors and within infected mammalian host cells. Our study reveals a new molecular mechanism of TCS-dependent gene regulation, and thereby advances fundamental understanding of transcriptional regulatory processes in bacteria.
Collapse
Affiliation(s)
- Xingru Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Melene A. Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| |
Collapse
|
18
|
Sharma G, Zee PC, Zea L, Curtis PD. Whole genome-scale assessment of gene fitness of Novosphingobium aromaticavorans during spaceflight. BMC Genomics 2023; 24:782. [PMID: 38102595 PMCID: PMC10725011 DOI: 10.1186/s12864-023-09799-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023] Open
Abstract
In microgravity, bacteria undergo intriguing physiological adaptations. There have been few attempts to assess global bacterial physiological responses to microgravity, with most studies only focusing on a handful of individual systems. This study assessed the fitness of each gene in the genome of the aromatic compound-degrading Alphaproteobacterium Novosphingobium aromaticavorans during growth in spaceflight. This was accomplished using Comparative TnSeq, which involves culturing the same saturating transposon mutagenized library under two different conditions. To assess gene fitness, a novel comparative TnSeq analytical tool was developed, named TnDivA, that is particularly useful in leveraging biological replicates. In this approach, transposon diversity is represented numerically using a modified Shannon diversity index, which was then converted into effective transposon density. This transformation accounts for variability in read distribution between samples, such as cases where reads were dominated by only a few transposon inserts. Effective density values were analyzed using multiple statistical methods, including log2-fold change, least-squares regression analysis, and Welch's t-test. The results obtained across applied statistical methods show a difference in the number of significant genes identified. However, the functional categories of genes important to growth in microgravity showed similar patterns. Lipid metabolism and transport, energy production, transcription, translation, and secondary metabolite biosynthesis and transport were shown to have high fitness during spaceflight. This suggests that core metabolic processes, including lipid and secondary metabolism, play an important role adapting to stress and promoting growth in microgravity.
Collapse
Affiliation(s)
- Gayatri Sharma
- Department of Biology, University of Mississippi, 402 Shoemaker Hall, University, MS, 38677, USA
| | - Peter C Zee
- Department of Biology, University of Mississippi, 402 Shoemaker Hall, University, MS, 38677, USA
| | - Luis Zea
- Aerospace Engineering Sciences, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Patrick D Curtis
- Department of Biology, University of Mississippi, 402 Shoemaker Hall, University, MS, 38677, USA.
| |
Collapse
|
19
|
Vacheron J, Heiman CM, Garneau JR, Kupferschmied P, de Jonge R, Garrido-Sanz D, Keel C. Molecular and evolutionary basis of O-antigenic polysaccharide-driven phage sensitivity in environmental pseudomonads. Microbiol Spectr 2023; 11:e0204923. [PMID: 37800913 PMCID: PMC10715155 DOI: 10.1128/spectrum.02049-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/16/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE The application of plant-beneficial microorganisms to protect crop plants is a promising alternative to the usage of chemicals. However, biocontrol research often faces difficulties in implementing this approach due to the inconsistency of the bacterial inoculant to establish itself within the root microbiome. Beneficial bacterial inoculants can be decimated by the presence of their natural predators, notably bacteriophages (also called phages). Thus, it is important to gain knowledge regarding the mechanisms behind phage-bacteria interactions to overcome this challenge. Here, we evidence that the major long O-antigenic polysaccharide (O-PS, O-antigen) of the widely used model plant-beneficial bacterium Pseudomonas protegens CHA0 is the receptor of its natural predator, the phage ΦGP100. We examined the distribution of the gene cluster directing the synthesis of this O-PS and identified signatures of horizontal gene acquisitions. Altogether, our study highlights the importance of bacterial cell surface structure variation in the complex interplay between phages and their Pseudomonas hosts.
Collapse
Affiliation(s)
- Jordan Vacheron
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Clara M. Heiman
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Julian R. Garneau
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Peter Kupferschmied
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Ronnie de Jonge
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, the Netherlands
| | - Daniel Garrido-Sanz
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
20
|
Trotereau J, Jouan R, Naquin D, Branger M, Schouler C, Velge P, Mergaert P, Virlogeux-Payant I. Construction and characterization of a saturated Tn-seq library of Salmonella Typhimurium ATCC 14028. Microbiol Resour Announc 2023; 12:e0036523. [PMID: 37795997 PMCID: PMC10653002 DOI: 10.1128/mra.00365-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/25/2023] [Indexed: 10/06/2023] Open
Abstract
Salmonella enterica is an important foodborne pathogen. Here, we present the construction and characterization of a high-density transposon sequencing library of the Salmonella Typhimurium ATCC 14028 strain. Essential, advantageous, and disadvantageous genes for growth in rich culture medium were identified on the chromosome and the pSLT plasmid.
Collapse
Affiliation(s)
| | - Romain Jouan
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | | | | | | | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | | |
Collapse
|
21
|
Alibayov B, Scasny A, Vidal AGJ, Murin L, Wong S, Edwards KS, Eichembaun Z, Punshon T, Jackson BP, Hopp MT, McDaniel LS, Akerley BJ, Imhof D, Vidal JE. Oxidation of hemoglobin in the lung parenchyma facilitates the differentiation of pneumococci into encapsulated bacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.567109. [PMID: 38014009 PMCID: PMC10680745 DOI: 10.1101/2023.11.14.567109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Pneumococcal pneumonia causes cytotoxicity in the lung parenchyma but the underlying mechanism involves multiple factors contributing to cell death. Here, we discovered that hydrogen peroxide produced by Streptococcus pneumoniae (Spn-H 2 O 2 ) plays a pivotal role by oxidizing hemoglobin, leading to its polymerization and subsequent release of labile heme. At physiologically relevant levels, heme selected a population of encapsulated pneumococci. In the absence of capsule and Spn-H 2 O 2 , host intracellular heme exhibited toxicity towards pneumococci, thus acting as an antibacterial mechanism. Further investigation revealed that heme-mediated toxicity required the ABC transporter GlnPQ. In vivo experiments demonstrated that pneumococci release H 2 O 2 to cause cytotoxicity in bronchi and alveoli through the non-proteolytic degradation of intracellular proteins such as actin, tubulin and GAPDH. Overall, our findings uncover a mechanism of lung toxicity mediated by oxidative stress that favor the growth of encapsulated pneumococci suggesting a therapeutic potential by targeting oxidative reactions. Graphical abstract Highlights Oxidation of hemoglobin by Streptococcus pneumoniae facilitates differentiation to encapsulated pneumococci in vivo Differentiated S. pneumoniae produces capsule and hydrogen peroxide (Spn-H 2 O 2 ) as defense mechanism against host heme-mediated toxicity. Spn-H 2 O 2 -induced lung toxicity causes the oxidation and non-proteolytic degradation of intracellular proteins tubulin, actin, and GAPDH. The ABC transporter GlnPQ is a heme-binding complex that makes Spn susceptible to heme toxicity.
Collapse
|
22
|
Wang Y, Gallagher LA, Andrade PA, Liu A, Humphreys IR, Turkarslan S, Cutler KJ, Arrieta-Ortiz ML, Li Y, Radey MC, McLean JS, Cong Q, Baker D, Baliga NS, Peterson SB, Mougous JD. Genetic manipulation of Patescibacteria provides mechanistic insights into microbial dark matter and the epibiotic lifestyle. Cell 2023; 186:4803-4817.e13. [PMID: 37683634 PMCID: PMC10633639 DOI: 10.1016/j.cell.2023.08.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/06/2023] [Accepted: 08/16/2023] [Indexed: 09/10/2023]
Abstract
Patescibacteria, also known as the candidate phyla radiation (CPR), are a diverse group of bacteria that constitute a disproportionately large fraction of microbial dark matter. Its few cultivated members, belonging mostly to Saccharibacteria, grow as epibionts on host Actinobacteria. Due to a lack of suitable tools, the genetic basis of this lifestyle and other unique features of Patescibacteira remain unexplored. Here, we show that Saccharibacteria exhibit natural competence, and we exploit this property for their genetic manipulation. Imaging of fluorescent protein-labeled Saccharibacteria provides high spatiotemporal resolution of phenomena accompanying epibiotic growth, and a transposon-insertion sequencing (Tn-seq) genome-wide screen reveals the contribution of enigmatic Saccharibacterial genes to growth on their hosts. Finally, we leverage metagenomic data to provide cutting-edge protein structure-based bioinformatic resources that support the strain Southlakia epibionticum and its corresponding host, Actinomyces israelii, as a model system for unlocking the molecular underpinnings of the epibiotic lifestyle.
Collapse
Affiliation(s)
- Yaxi Wang
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Larry A Gallagher
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Pia A Andrade
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Andi Liu
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Ian R Humphreys
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | | | - Kevin J Cutler
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | | | - Yaqiao Li
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Institute for Systems Biology, Seattle, WA 98109, USA
| | - Matthew C Radey
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Jeffrey S McLean
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Department of Periodontics, University of Washington, Seattle, WA 98195, USA
| | - Qian Cong
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Institute for Protein Design, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98109, USA
| | | | - S Brook Peterson
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Joseph D Mougous
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98109, USA; Microbial Interactions and Microbiome Center, University of Washington, Seattle, WA 98195, USA.
| |
Collapse
|
23
|
Fiebig A, Schnizlein MK, Pena-Rivera S, Trigodet F, Dubey AA, Hennessy M, Basu A, Pott S, Dalal S, Rubin D, Sogin ML, Murat Eren A, Chang EB, Crosson S. Bile acid fitness determinants of a Bacteroides fragilis isolate from a human pouchitis patient. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.11.540287. [PMID: 37214927 PMCID: PMC10197588 DOI: 10.1101/2023.05.11.540287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bacteroides fragilis comprises 1-5% of the gut microbiota in healthy humans but can expand to >50% of the population in ulcerative colitis (UC) patients experiencing inflammation. The mechanisms underlying such microbial blooms are poorly understood, but the gut of UC patients has physicochemical features that differ from healthy patients and likely impact microbial physiology. For example, levels of the secondary bile acid deoxycholate (DC) are highly reduced in the ileoanal J-pouch of UC colectomy patients. We isolated a B. fragilis strain from a UC patient with pouch inflammation (i.e. pouchitis) and developed it as a genetic model system to identify genes and pathways that are regulated by DC and that impact B. fragilis fitness in DC and crude bile. Treatment of B. fragilis with a physiologically relevant concentration of DC reduced cell growth and remodeled transcription of one-quarter of the genome. DC strongly induced expression of chaperones and select transcriptional regulators and efflux systems and downregulated protein synthesis genes. Using a barcoded collection of ≈50,000 unique insertional mutants, we further defined B. fragilis genes that contribute to fitness in media containing DC or crude bile. Genes impacting cell envelope functions including cardiolipin synthesis, cell surface glycosylation, and systems implicated in sodium-dependent bioenergetics were major bile acid fitness factors. As expected, there was limited overlap between transcriptionally regulated genes and genes that impacted fitness in bile when disrupted. Our study provides a genome-scale view of a B. fragilis bile response and genetic determinants of its fitness in DC and crude bile.
Collapse
Affiliation(s)
- Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Matthew K. Schnizlein
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Selymar Pena-Rivera
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Florian Trigodet
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Abhishek Anil Dubey
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Miette Hennessy
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Anindita Basu
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Sebastian Pott
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Sushila Dalal
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - David Rubin
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | | | - A. Murat Eren
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Helmholtz Institute for Functional Marine Biodiversity, University of Oldenburg, Oldenburg, Germany
| | - Eugene B. Chang
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| |
Collapse
|
24
|
Lo HY, Long DR, Holmes EA, Penewit K, Hodgson T, Lewis JD, Waalkes A, Salipante SJ. Transposon sequencing identifies genes impacting Staphylococcus aureus invasion in a human macrophage model. Infect Immun 2023; 91:e0022823. [PMID: 37676013 PMCID: PMC10580828 DOI: 10.1128/iai.00228-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/13/2023] [Indexed: 09/08/2023] Open
Abstract
Staphylococcus aureus is a facultative intracellular pathogen in many host cell types, facilitating its persistence in chronic infections. The genes contributing to intracellular pathogenesis have not yet been fully enumerated. Here, we cataloged genes influencing S. aureus invasion and survival within human THP-1 derived macrophages using two laboratory strains (ATCC2913 and JE2). We developed an in vitro transposition method to produce highly saturated transposon mutant libraries in S. aureus and performed transposon insertion sequencing (Tn-Seq) to identify candidate genes with significantly altered abundance following macrophage invasion. While some significant genes were strain-specific, 108 were identified as common across both S. aureus strains, with most (n = 106) being required for optimal macrophage infection. We used CRISPR interference (CRISPRi) to functionally validate phenotypic contributions for a subset of genes. Of the 20 genes passing validation, seven had previously identified roles in S. aureus virulence, and 13 were newly implicated. Validated genes frequently evidenced strain-specific effects, yielding opposing phenotypes when knocked down in the alternative strain. Genomic analysis of de novo mutations occurring in groups (n = 237) of clonally related S. aureus isolates from the airways of chronically infected individuals with cystic fibrosis (CF) revealed significantly greater in vivo purifying selection in conditionally essential candidate genes than those not associated with macrophage invasion. This study implicates a core set of genes necessary to support macrophage invasion by S. aureus, highlights strain-specific differences in phenotypic effects of effector genes, and provides evidence for selection of candidate genes identified by Tn-Seq analyses during chronic airway infection in CF patients in vivo.
Collapse
Affiliation(s)
- Hsin-Yu Lo
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Dustin R. Long
- Division of Critical Care Medicine, Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Elizbeth A. Holmes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Kelsi Penewit
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Taylor Hodgson
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Janessa D. Lewis
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Adam Waalkes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Stephen J. Salipante
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| |
Collapse
|
25
|
Freiberg JA, Ruiz VMR, Green ER, Skaar EP. Restriction of Arginine Induces Antibiotic Tolerance in Staphylococcus aureus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.561972. [PMID: 37873095 PMCID: PMC10592767 DOI: 10.1101/2023.10.12.561972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Staphylococcus aureus is responsible for a substantial number of invasive infections globally each year. These infections are problematic because they are frequently recalcitrant to antibiotic treatment, particularly when they are caused by Methicillin-Resistant Staphylococcus aureus (MRSA). Antibiotic tolerance, the ability for bacteria to persist despite normally lethal doses of antibiotics, is responsible for most antibiotic treatment failure in MRSA infections. To understand how antibiotic tolerance is induced, S. aureus biofilms exposed to multiple anti-MRSA antibiotics (vancomycin, ceftaroline, delafloxacin, and linezolid) were examined using both quantitative proteomics and transposon sequencing. These screens indicated that arginine metabolism is involved in antibiotic tolerance within a biofilm and led to the hypothesis that depletion of arginine within S. aureus communities can induce antibiotic tolerance. Consistent with this hypothesis, inactivation of argH, the final gene in the arginine synthesis pathway, induces antibiotic tolerance under conditions in which the parental strain is susceptible to antibiotics. Arginine restriction was found to induce antibiotic tolerance via inhibition of protein synthesis. Finally, although S. aureus fitness in a mouse skin infection model is decreased in an argH mutant, its ability to survive in vivo during antibiotic treatment with vancomycin is enhanced, highlighting the relationship between arginine metabolism and antibiotic tolerance during S. aureus infection. Uncovering this link between arginine metabolism and antibiotic tolerance has the potential to open new therapeutic avenues targeting previously recalcitrant S. aureus infections.
Collapse
Affiliation(s)
- Jeffrey A. Freiberg
- Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Valeria M. Reyes Ruiz
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Erin R. Green
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Microbiology, University of Chicago, Chicago, IL 60637
| | - Eric P. Skaar
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
| |
Collapse
|
26
|
Chen X, Alakavuklar MA, Fiebig A, Crosson S. Cross regulation in a three-component cell envelope stress signaling system of Brucella. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.15.536747. [PMID: 37873345 PMCID: PMC10592609 DOI: 10.1101/2023.04.15.536747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
A multi-layered structure known as the cell envelope separates the controlled interior of bacterial cells from a fluctuating physical and chemical environment. The transcription of genes that determine cell envelope structure and function is commonly regulated by two-component signaling systems (TCS), comprising a sensor histidine kinase and a cognate response regulator. To identify TCS genes that contribute to cell envelope function in the intracellular mammalian pathogen, Brucella ovis, we subjected a collection of non-essential TCS deletion mutants to compounds that disrupt cell membranes and the peptidoglycan cell wall. Our screen led to the discovery of three TCS proteins that coordinately function to confer resistance to cell envelope stressors and to support B. ovis replication in the intracellular niche. This tripartite regulatory system includes the known cell envelope regulator, CenR, and a previously uncharacterized TCS, EssR-EssS, which is widely conserved in Alphaproteobacteria. The CenR and EssR response regulators bind a shared set of sites on the B. ovis chromosomes to control transcription of an overlapping set of genes with cell envelope functions. CenR directly interacts with EssR and functions to stimulate phosphoryl transfer from the EssS kinase to EssR, while CenR and EssR control the cellular levels of each other via a post-transcriptional mechanism. Our data provide evidence for a new mode of TCS cross-regulation in which a non-cognate response regulator affects both the activity and protein levels of a cognate TCS protein pair.
Collapse
Affiliation(s)
- Xingru Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Melene A Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan USA
| |
Collapse
|
27
|
Alakavuklar MA, Fiebig A, Crosson S. The Brucella Cell Envelope. Annu Rev Microbiol 2023; 77:233-253. [PMID: 37104660 PMCID: PMC10787603 DOI: 10.1146/annurev-micro-032521-013159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The cell envelope is a multilayered structure that insulates the interior of bacterial cells from an often chaotic outside world. Common features define the envelope across the bacterial kingdom, but the molecular mechanisms by which cells build and regulate this critical barrier are diverse and reflect the evolutionary histories of bacterial lineages. Intracellular pathogens of the genus Brucella exhibit marked differences in cell envelope structure, regulation, and biogenesis when compared to more commonly studied gram-negative bacteria and therefore provide an excellent comparative model for study of the gram-negative envelope. We review distinct features of the Brucella envelope, highlighting a conserved regulatory system that links cell cycle progression to envelope biogenesis and cell division. We further discuss recently discovered structural features of the Brucella envelope that ensure envelope integrity and that facilitate cell survival in the face of host immune stressors.
Collapse
Affiliation(s)
- Melene A Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| |
Collapse
|
28
|
Kado T, Akbary Z, Motooka D, Sparks IL, Melzer ES, Nakamura S, Rojas ER, Morita YS, Siegrist MS. A cell wall synthase accelerates plasma membrane partitioning in mycobacteria. eLife 2023; 12:e81924. [PMID: 37665120 PMCID: PMC10547480 DOI: 10.7554/elife.81924] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 09/02/2023] [Indexed: 09/05/2023] Open
Abstract
Lateral partitioning of proteins and lipids shapes membrane function. In model membranes, partitioning can be influenced both by bilayer-intrinsic factors like molecular composition and by bilayer-extrinsic factors such as interactions with other membranes and solid supports. While cellular membranes can departition in response to bilayer-intrinsic or -extrinsic disruptions, the mechanisms by which they partition de novo are largely unknown. The plasma membrane of Mycobacterium smegmatis spatially and biochemically departitions in response to the fluidizing agent benzyl alcohol, then repartitions upon fluidizer washout. By screening for mutants that are sensitive to benzyl alcohol, we show that the bifunctional cell wall synthase PonA2 promotes membrane partitioning and cell growth during recovery from benzyl alcohol exposure. PonA2's role in membrane repartitioning and regrowth depends solely on its conserved transglycosylase domain. Active cell wall polymerization promotes de novo membrane partitioning and the completed cell wall polymer helps to maintain membrane partitioning. Our work highlights the complexity of membrane-cell wall interactions and establishes a facile model system for departitioning and repartitioning cellular membranes.
Collapse
Affiliation(s)
- Takehiro Kado
- Department of Microbiology, University of Massachusetts AmherstAmherstUnited States
| | - Zarina Akbary
- Department of Biology, New York UniversityNew YorkUnited States
| | - Daisuke Motooka
- Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan
| | - Ian L Sparks
- Department of Microbiology, University of Massachusetts AmherstAmherstUnited States
| | - Emily S Melzer
- Department of Microbiology, University of Massachusetts AmherstAmherstUnited States
| | - Shota Nakamura
- Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan
| | - Enrique R Rojas
- Department of Biology, New York UniversityNew YorkUnited States
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts AmherstAmherstUnited States
- Molecular and Cellular Graduate Program, University of Massachusetts AmherstAmherstUnited States
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts AmherstAmherstUnited States
- Molecular and Cellular Graduate Program, University of Massachusetts AmherstAmherstUnited States
| |
Collapse
|
29
|
Levendosky K, Janisch N, Quadri LEN. Comprehensive essentiality analysis of the Mycobacterium kansasii genome by saturation transposon mutagenesis and deep sequencing. mBio 2023; 14:e0057323. [PMID: 37350613 PMCID: PMC10470612 DOI: 10.1128/mbio.00573-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/01/2023] [Indexed: 06/24/2023] Open
Abstract
Mycobacterium kansasii (Mk) is an opportunistic pathogen that is frequently isolated from urban water systems, posing a health risk to susceptible individuals. Despite its ability to cause tuberculosis-like pulmonary disease, very few studies have probed the genetics of this opportunistic pathogen. Here, we report a comprehensive essentiality analysis of the Mk genome. Deep sequencing of a high-density library of Mk Himar1 transposon mutants revealed that 86.8% of the chromosomal thymine-adenine (TA) dinucleotide target sites were permissive to insertion, leaving 13.2% TA sites unoccupied. Our analysis identified 394 of the 5,350 annotated open reading frames (ORFs) as essential. The majority of these essential ORFs (84.8%) share essential mutual orthologs with Mycobacterium tuberculosis (Mtb). A comparative genomics analysis identified 139 Mk essential ORFs that share essential orthologs in four other species of mycobacteria. Thirteen Mk essential ORFs share orthologs in all four species that were identified as being not essential, while only two Mk essential ORFs are absent in all species compared. We used the essentiality data and a comparative genomics analysis reported here to highlight differences in essentiality between candidate Mtb drug targets and the corresponding Mk orthologs. Our findings suggest that the Mk genome encodes redundant or additional pathways that may confound validation of potential Mtb drugs and drug target candidates against the opportunistic pathogen. Additionally, we identified 57 intergenic regions containing four or more consecutive unoccupied TA sites. A disproportionally large number of these regions were located upstream of pe/ppe genes. Finally, we present an essentiality and orthology analysis of the Mk pRAW-like plasmid, pMK1248. IMPORTANCE Mk is one of the most common nontuberculous mycobacterial pathogens associated with tuberculosis-like pulmonary disease. Drug resistance emergence is a threat to the control of Mk infections, which already requires long-term, multidrug courses. A comprehensive understanding of Mk biology is critical to facilitate the development of new and more efficacious therapeutics against Mk. We combined transposon-based mutagenesis with analysis of insertion site identification data to uncover genes and other genomic regions required for Mk growth. We also compared the gene essentiality data set of Mk to those available for several other mycobacteria. This analysis highlighted key similarities and differences in the biology of Mk compared to these other species. Altogether, the genome-wide essentiality information generated and the results of the cross-species comparative genomics analysis represent valuable resources to assist the process of identifying and prioritizing potential Mk drug target candidates and to guide future studies on Mk biology.
Collapse
Affiliation(s)
- Keith Levendosky
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, USA
- Biology Program, Graduate Center, Biology Program, Graduate Center, City University of New York, New York, New York, USA
| | - Niklas Janisch
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, USA
- Biology Program, Graduate Center, Biology Program, Graduate Center, City University of New York, New York, New York, USA
| | - Luis E. N. Quadri
- Department of Biology, Brooklyn College, City University of New York, Brooklyn, New York, USA
- Biology Program, Graduate Center, Biology Program, Graduate Center, City University of New York, New York, New York, USA
- Biochemistry Program, Graduate Center, City University of New York, New York, New York, USA
| |
Collapse
|
30
|
Meade RK, Long JE, Jinich A, Rhee KY, Ashbrook DG, Williams RW, Sassetti CM, Smith CM. Genome-wide screen identifies host loci that modulate Mycobacterium tuberculosis fitness in immunodivergent mice. G3 (BETHESDA, MD.) 2023; 13:jkad147. [PMID: 37405387 PMCID: PMC10468300 DOI: 10.1093/g3journal/jkad147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/05/2023] [Accepted: 06/27/2023] [Indexed: 07/06/2023]
Abstract
Genetic differences among mammalian hosts and among strains of Mycobacterium tuberculosis (Mtb) are well-established determinants of tuberculosis (TB) patient outcomes. The advent of recombinant inbred mouse panels and next-generation transposon mutagenesis and sequencing approaches has enabled dissection of complex host-pathogen interactions. To identify host and pathogen genetic determinants of Mtb pathogenesis, we infected members of the highly diverse BXD family of strains with a comprehensive library of Mtb transposon mutants (TnSeq). Members of the BXD family segregate for Mtb-resistant C57BL/6J (B6 or B) and Mtb-susceptible DBA/2J (D2 or D) haplotypes. The survival of each bacterial mutant was quantified within each BXD host, and we identified those bacterial genes that were differentially required for Mtb fitness across BXD genotypes. Mutants that varied in survival among the host family of strains were leveraged as reporters of "endophenotypes," each bacterial fitness profile directly probing specific components of the infection microenvironment. We conducted quantitative trait loci (QTL) mapping of these bacterial fitness endophenotypes and identified 140 host-pathogen QTL (hpQTL). We located a QTL hotspot on chromosome 6 (75.97-88.58 Mb) associated with the genetic requirement of multiple Mtb genes: Rv0127 (mak), Rv0359 (rip2), Rv0955 (perM), and Rv3849 (espR). Together, this screen reinforces the utility of bacterial mutant libraries as precise reporters of the host immunological microenvironment during infection and highlights specific host-pathogen genetic interactions for further investigation. To enable downstream follow-up for both bacterial and mammalian genetic research communities, all bacterial fitness profiles have been deposited into GeneNetwork.org and added into the comprehensive collection of TnSeq libraries in MtbTnDB.
Collapse
Affiliation(s)
- Rachel K Meade
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC 27710, USA
| | - Jarukit E Long
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA 01655, USA
- Research Animal Diagnostic Services, Charles River Laboratories, Wilmington, MA 01887, USA
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Cornell Medical College, New York, NY 10021, USA
| | - Kyu Y Rhee
- Division of Infectious Diseases, Weill Cornell Medical College, New York, NY 10021, USA
| | - David G Ashbrook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Christopher M Sassetti
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA 01655, USA
| | - Clare M Smith
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC 27710, USA
| |
Collapse
|
31
|
Peterson EJR, Brooks AN, Reiss DJ, Kaur A, Do J, Pan M, Wu WJ, Morrison R, Srinivas V, Carter W, Arrieta-Ortiz ML, Ruiz RA, Bhatt A, Baliga NS. MtrA modulates Mycobacterium tuberculosis cell division in host microenvironments to mediate intrinsic resistance and drug tolerance. Cell Rep 2023; 42:112875. [PMID: 37542718 PMCID: PMC10480492 DOI: 10.1016/j.celrep.2023.112875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 04/21/2023] [Accepted: 07/11/2023] [Indexed: 08/07/2023] Open
Abstract
The success of Mycobacterium tuberculosis (Mtb) is largely attributed to its ability to physiologically adapt and withstand diverse localized stresses within host microenvironments. Here, we present a data-driven model (EGRIN 2.0) that captures the dynamic interplay of environmental cues and genome-encoded regulatory programs in Mtb. Analysis of EGRIN 2.0 shows how modulation of the MtrAB two-component signaling system tunes Mtb growth in response to related host microenvironmental cues. Disruption of MtrAB by tunable CRISPR interference confirms that the signaling system regulates multiple peptidoglycan hydrolases, among other targets, that are important for cell division. Further, MtrA decreases the effectiveness of antibiotics by mechanisms of both intrinsic resistance and drug tolerance. Together, the model-enabled dissection of complex MtrA regulation highlights its importance as a drug target and illustrates how EGRIN 2.0 facilitates discovery and mechanistic characterization of Mtb adaptation to specific host microenvironments within the host.
Collapse
Affiliation(s)
| | | | - David J Reiss
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Amardeep Kaur
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Julie Do
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Min Pan
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Wei-Ju Wu
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Robert Morrison
- Laboratory of Malaria, Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | | | - Warren Carter
- Institute for Systems Biology, Seattle, WA 98109, USA
| | | | - Rene A Ruiz
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Apoorva Bhatt
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Nitin S Baliga
- Institute for Systems Biology, Seattle, WA 98109, USA; Departments of Biology and Microbiology, University of Washington, Seattle, WA 98195, USA; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA; Lawrence Berkeley National Lab, Berkeley, CA 94720, USA.
| |
Collapse
|
32
|
Aromolaran OT, Isewon I, Adedeji E, Oswald M, Adebiyi E, Koenig R, Oyelade J. Heuristic-enabled active machine learning: A case study of predicting essential developmental stage and immune response genes in Drosophila melanogaster. PLoS One 2023; 18:e0288023. [PMID: 37556452 PMCID: PMC10411809 DOI: 10.1371/journal.pone.0288023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/18/2023] [Indexed: 08/11/2023] Open
Abstract
Computational prediction of absolute essential genes using machine learning has gained wide attention in recent years. However, essential genes are mostly conditional and not absolute. Experimental techniques provide a reliable approach of identifying conditionally essential genes; however, experimental methods are laborious, time and resource consuming, hence computational techniques have been used to complement the experimental methods. Computational techniques such as supervised machine learning, or flux balance analysis are grossly limited due to the unavailability of required data for training the model or simulating the conditions for gene essentiality. This study developed a heuristic-enabled active machine learning method based on a light gradient boosting model to predict essential immune response and embryonic developmental genes in Drosophila melanogaster. We proposed a new sampling selection technique and introduced a heuristic function which replaces the human component in traditional active learning models. The heuristic function dynamically selects the unlabelled samples to improve the performance of the classifier in the next iteration. Testing the proposed model with four benchmark datasets, the proposed model showed superior performance when compared to traditional active learning models (random sampling and uncertainty sampling). Applying the model to identify conditionally essential genes, four novel essential immune response genes and a list of 48 novel genes that are essential in embryonic developmental condition were identified. We performed functional enrichment analysis of the predicted genes to elucidate their biological processes and the result evidence our predictions. Immune response and embryonic development related processes were significantly enriched in the essential immune response and embryonic developmental genes, respectively. Finally, we propose the predicted essential genes for future experimental studies and use of the developed tool accessible at http://heal.covenantuniversity.edu.ng for conditional essentiality predictions.
Collapse
Affiliation(s)
- Olufemi Tony Aromolaran
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Itunu Isewon
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Eunice Adedeji
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
- Department of Biochemistry, Covenant University, Ota, Ogun State, Nigeria
| | - Marcus Oswald
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum, Jena, Germany
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum, Jena, Germany
| | - Ezekiel Adebiyi
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| | - Rainer Koenig
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum, Jena, Germany
- Institute of Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum, Jena, Germany
| | - Jelili Oyelade
- Department of Computer & Information Sciences, Covenant University, Ota, Ogun State, Nigeria
- Covenant University Bioinformatics Research (CUBRe), Covenant University, Ota, Ogun State, Nigeria
| |
Collapse
|
33
|
Davey LE, Malkus PN, Villa M, Dolat L, Holmes ZC, Letourneau J, Ansaldo E, David LA, Barton GM, Valdivia RH. A genetic system for Akkermansia muciniphila reveals a role for mucin foraging in gut colonization and host sterol biosynthesis gene expression. Nat Microbiol 2023; 8:1450-1467. [PMID: 37337046 DOI: 10.1038/s41564-023-01407-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/10/2023] [Indexed: 06/21/2023]
Abstract
Akkermansia muciniphila, a mucophilic member of the gut microbiota, protects its host against metabolic disorders. Because it is genetically intractable, the mechanisms underlying mucin metabolism, gut colonization and its impact on host physiology are not well understood. Here we developed and applied transposon mutagenesis to identify genes important for intestinal colonization and for the use of mucin. An analysis of transposon mutants indicated that de novo biosynthesis of amino acids was required for A. muciniphila growth on mucin medium and that many glycoside hydrolases are redundant. We observed that mucin degradation products accumulate in internal compartments within bacteria in a process that requires genes encoding pili and a periplasmic protein complex, which we term mucin utilization locus (MUL) genes. We determined that MUL genes were required for intestinal colonization in mice but only when competing with other microbes. In germ-free mice, MUL genes were required for A. muciniphila to repress genes important for cholesterol biosynthesis in the colon. Our genetic system for A. muciniphila provides an important tool with which to uncover molecular links between the metabolism of mucins, regulation of lipid homeostasis and potential probiotic activities.
Collapse
Affiliation(s)
- Lauren E Davey
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA.
- Duke Microbiome Center, Duke University, Durham, NC, USA.
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
| | - Per N Malkus
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Max Villa
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Lee Dolat
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Zachary C Holmes
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Jeff Letourneau
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Eduard Ansaldo
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Lawrence A David
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- Duke Microbiome Center, Duke University, Durham, NC, USA
| | - Gregory M Barton
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA.
- Duke Microbiome Center, Duke University, Durham, NC, USA.
| |
Collapse
|
34
|
Wang Y, Gallagher LA, Andrade PA, Liu A, Humphreys IR, Turkarslan S, Cutler KJ, Arrieta-Ortiz ML, Li Y, Radey MC, McLean JS, Cong Q, Baker D, Baliga NS, Peterson SB, Mougous JD. Genetic manipulation of candidate phyla radiation bacteria provides functional insights into microbial dark matter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539146. [PMID: 37205512 PMCID: PMC10187176 DOI: 10.1101/2023.05.02.539146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The study of bacteria has yielded fundamental insights into cellular biology and physiology, biotechnological advances and many therapeutics. Yet due to a lack of suitable tools, the significant portion of bacterial diversity held within the candidate phyla radiation (CPR) remains inaccessible to such pursuits. Here we show that CPR bacteria belonging to the phylum Saccharibacteria exhibit natural competence. We exploit this property to develop methods for their genetic manipulation, including the insertion of heterologous sequences and the construction of targeted gene deletions. Imaging of fluorescent protein-labeled Saccharibacteria provides high spatiotemporal resolution of phenomena accompanying epibiotic growth and a transposon insertion sequencing genome-wide screen reveals the contribution of enigmatic Saccharibacterial genes to growth on their Actinobacteria hosts. Finally, we leverage metagenomic data to provide cutting-edge protein structure-based bioinformatic resources that support the strain Southlakia epibionticum and its corresponding host, Actinomyces israelii , as a model system for unlocking the molecular underpinnings of the epibiotic lifestyle.
Collapse
Affiliation(s)
- Yaxi Wang
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Larry A. Gallagher
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Pia A. Andrade
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Andi Liu
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Ian R. Humphreys
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
- Institute for Protein Design, Seattle, WA 98109, USA
| | | | - Kevin J. Cutler
- Department of Physics, University of Washington, Seattle, WA 98195, USA
| | | | - Yaqiao Li
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Matthew C. Radey
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Jeffrey S. McLean
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
- Department of Periodontics, University of Washington, Seattle, WA 98195, USA
| | - Qian Cong
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
- Institute for Protein Design, Seattle, WA 98109, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | | | - S. Brook Peterson
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Joseph D. Mougous
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
- Microbial Interactions and Microbiome Center, University of Washington, Seattle, WA 98109, USA
| |
Collapse
|
35
|
Aurass P, Kim S, Pinedo V, Cava F, Isberg RR. Identification of Genes Required for Long-Term Survival of Legionella pneumophila in Water. mSphere 2023; 8:e0045422. [PMID: 36988466 PMCID: PMC10117105 DOI: 10.1128/msphere.00454-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 02/24/2023] [Indexed: 03/30/2023] Open
Abstract
Long-term survival of Legionella pneumophila in aquatic environments is thought to be important for facilitating epidemic outbreaks. Eliminating bacterial colonization in plumbing systems is the primary strategy that depletes this reservoir and prevents disease. To uncover L. pneumophila determinants facilitating survival in water, a Tn-seq strategy was used to identify survival-defective mutants during 50-day starvation in tap water at 42°C. The mutants with the most drastic survival defects carried insertions in electron transport chain genes, indicating that membrane energy charge and/or ATP synthesis requires the generation of a proton gradient by the respiratory chain to maintain survival in the presence of water stress. In addition, periplasmically localized proteins that are known (EnhC) or hypothesized (lpg1697) to stabilize the cell wall against turnover were essential for water survival. To test that the identified mutations disrupted water survival, candidate genes were knocked down by CRISPRi. The vast majority of knockdown strains with verified transcript depletion showed remarkably low viability after 50-day incubations. To demonstrate that maintenance of cell wall integrity was an important survival determinant, a deletion mutation in lpg1697, in a gene encoding a predicted l,d-transpeptidase domain, was analyzed. The loss of this gene resulted in increased osmolar sensitivity and carbenicillin hypersensitivity relative to the wild type, as predicted for loss of an l,d-transpeptidase. These results indicate that the L. pneumophila envelope has been evolutionarily selected to allow survival under conditions in which the bacteria are subjected to long-term exposure to starvation and low osmolar conditions. IMPORTANCE Water is the primary vector for transmission of L. pneumophila to humans, and the pathogen is adapted to persist in this environment for extended periods of time. Preventing survival of L. pneumophila in water is therefore critical for prevention of Legionnaires' disease. We analyzed dense transposon mutation pools for strains with severe survival defects during a 50-day water incubation at 42°C. By tracking the associated transposon insertion sites in the genome, we defined a distinct essential gene set for water survival and demonstrate that a predicted peptidoglycan cross-linking enzyme, lpg1697, and components of the electron transport chain are required to ensure survival of the pathogen. Our results indicate that select characteristics of the cell wall and components of the respiratory chain of L. pneumophila are primary evolutionary targets being shaped to promote its survival in water.
Collapse
Affiliation(s)
- Philipp Aurass
- Department of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Seongok Kim
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Victor Pinedo
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Ralph R. Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| |
Collapse
|
36
|
Meade RK, Long JE, Jinich A, Rhee KY, Ashbrook DG, Williams RW, Sassetti CM, Smith CM. Genome-wide screen identifies host loci that modulate M. tuberculosis fitness in immunodivergent mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.05.528534. [PMID: 36945430 PMCID: PMC10028809 DOI: 10.1101/2023.03.05.528534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Genetic differences among mammalian hosts and Mycobacterium tuberculosis ( Mtb ) strains determine diverse tuberculosis (TB) patient outcomes. The advent of recombinant inbred mouse panels and next-generation transposon mutagenesis and sequencing approaches has enabled dissection of complex host- pathogen interactions. To identify host and pathogen genetic determinants of Mtb pathogenesis, we infected members of the BXD family of mouse strains with a comprehensive library of Mtb transposon mutants (TnSeq). Members of the BXD family segregate for Mtb -resistant C57BL/6J (B6 or B ) and Mtb -susceptible DBA/2J (D2 or D ) haplotypes. The survival of each bacterial mutant was quantified within each BXD host, and we identified those bacterial genes that were differentially required for Mtb fitness across BXD genotypes. Mutants that varied in survival among the host family of strains were leveraged as reporters for "endophenotypes", each bacterial fitness profile directly probing specific components of the infection microenvironment. We conducted QTL mapping of these bacterial fitness endophenotypes and identified 140 h ost- p athogen quantitative trait loci ( hp QTL). We identified a QTL hotspot on chromosome 6 (75.97-88.58 Mb) associated with the genetic requirement of multiple Mtb genes; Rv0127 ( mak ), Rv0359 ( rip2 ), Rv0955 ( perM ), and Rv3849 ( espR ). Together, this screen reinforces the utility of bacterial mutant libraries as precise reporters of the host immunological microenvironment during infection and highlights specific host-pathogen genetic interactions for further investigation. To enable downstream follow-up for both bacterial and mammalian genetic research communities, all bacterial fitness profiles have been deposited into GeneNetwork.org and added into the comprehensive collection of TnSeq libraries in MtbTnDB.
Collapse
Affiliation(s)
- Rachel K. Meade
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC, USA
| | - Jarukit E. Long
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
- Charles River Laboratories, Research Animal Diagnostic Services, Wilmington, MA, USA
| | - Adrian Jinich
- Division of Infectious Diseases, Weill Cornell Medical College, NY, USA
| | - Kyu Y. Rhee
- Division of Infectious Diseases, Weill Cornell Medical College, NY, USA
| | - David G. Ashbrook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Robert W. Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, USA
| | - Clare M. Smith
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
- University Program in Genetics and Genomics, Duke University, Durham, NC, USA
| |
Collapse
|
37
|
Rhizobial migration toward roots mediated by FadL-ExoFQP modulation of extracellular long-chain AHLs. THE ISME JOURNAL 2023; 17:417-431. [PMID: 36627434 PMCID: PMC9938287 DOI: 10.1038/s41396-023-01357-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023]
Abstract
Migration from rhizosphere to rhizoplane is a key selecting process in root microbiome assembly, but not fully understood. Rhizobiales members are overrepresented in the core root microbiome of terrestrial plants, and here we report a genome-wide transposon-sequencing of rhizoplane fitness genes of beneficial Sinorhizobium fredii on wild soybean, cultivated soybean, rice, and maize. There were few genes involved in broad-host-range rhizoplane colonization. The fadL mutant lacking a fatty acid transporter exhibited high colonization rates, while mutations in exoFQP (encoding membrane proteins directing exopolysaccharide polymerization and secretion), but not those in exo genes essential for exopolysaccharide biosynthesis, led to severely impaired colonization rates. This variation was not explainable by their rhizosphere and rhizoplane survivability, and associated biofilm and exopolysaccharide production, but consistent with their migration ability toward rhizoplane, and associated surface motility and the mixture of quorum-sensing AHLs (N-acylated-L-homoserine lactones). Genetics and physiology evidences suggested that FadL mediated long-chain AHL uptake while ExoF mediated the secretion of short-chain AHLs which negatively affected long-chain AHL biosynthesis. The fadL and exoF mutants had elevated and depleted extracellular long-chain AHLs, respectively. A synthetic mixture of long-chain AHLs mimicking that of the fadL mutant can improve rhizobial surface motility. When this AHL mixture was spotted into rhizosphere, the migration toward roots and rhizoplane colonization of S. fredii were enhanced in a diffusible way. This work adds novel parts managing extracellular AHLs, which modulate bacterial migration toward rhizoplane. The FadL-ExoFQP system is conserved in Alphaproteobacteria and may shape the "home life" of diverse keystone rhizobacteria.
Collapse
|
38
|
Sullivan MR, McGowen K, Liu Q, Akusobi C, Young DC, Mayfield JA, Raman S, Wolf ID, Moody DB, Aldrich CC, Muir A, Rubin EJ. Biotin-dependent cell envelope remodelling is required for Mycobacterium abscessus survival in lung infection. Nat Microbiol 2023; 8:481-497. [PMID: 36658396 PMCID: PMC9992005 DOI: 10.1038/s41564-022-01307-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 12/14/2022] [Indexed: 01/21/2023]
Abstract
Mycobacterium abscessus is an emerging pathogen causing lung infection predominantly in patients with underlying structural abnormalities or lung disease and is resistant to most frontline antibiotics. As the pathogenic mechanisms of M. abscessus in the context of the lung are not well-understood, we developed an infection model using air-liquid interface culture and performed a transposon mutagenesis and sequencing screen to identify genes differentially required for bacterial survival in the lung. Biotin cofactor synthesis was required for M. abscessus growth due to increased intracellular biotin demand, while pharmacological inhibition of biotin synthesis prevented bacterial proliferation. Biotin was required for fatty acid remodelling, which increased cell envelope fluidity and promoted M. abscessus survival in the alkaline lung environment. Together, these results indicate that biotin-dependent fatty acid remodelling plays a critical role in pathogenic adaptation to the lung niche, suggesting that biotin synthesis and fatty acid metabolism might provide therapeutic targets for treatment of M. abscessus infection.
Collapse
Affiliation(s)
- Mark R Sullivan
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Kerry McGowen
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Qiang Liu
- Department of Medicinal Chemistry, University of Minnesota College of Pharmacy, Minneapolis, MN, USA
| | - Chidiebere Akusobi
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - David C Young
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jacob A Mayfield
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sahadevan Raman
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ian D Wolf
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - D Branch Moody
- Division of Rheumatology, Immunity and Inflammation, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota College of Pharmacy, Minneapolis, MN, USA
| | - Alexander Muir
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
| | - Eric J Rubin
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
| |
Collapse
|
39
|
Dual-Uptake Mode of the Antibiotic Phazolicin Prevents Resistance Acquisition by Gram-Negative Bacteria. mBio 2023; 14:e0021723. [PMID: 36802165 PMCID: PMC10128002 DOI: 10.1128/mbio.00217-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
Phazolicin (PHZ) is a peptide antibiotic exhibiting narrow-spectrum activity against rhizobia closely related to its producer, Rhizobium sp. strain Pop5. Here, we show that the frequency of spontaneous PHZ-resistant mutants in Sinorhizobium meliloti is below the detection limit. We find that PHZ can enter S. meliloti cells through two distinct promiscuous peptide transporters, BacA and YejABEF, which belong to the SLiPT (SbmA-like peptide transporter) and ABC (ATP-binding cassette) transporter families, respectively. The dual-uptake mode explains the lack of observed resistance acquisition because the simultaneous inactivation of both transporters is necessary for resistance to PHZ. Since both BacA and YejABEF are essential for the development of functional symbiosis of S. meliloti with leguminous plants, the unlikely acquisition of PHZ resistance via the inactivation of these transporters is further disfavored. A whole-genome transposon sequencing screen did not reveal additional genes that can provide strong PHZ resistance when inactivated. However, it was found that the capsular polysaccharide KPS, the novel putative envelope polysaccharide PPP (PHZ-protecting polysaccharide), as well as the peptidoglycan layer jointly contribute to the sensitivity of S. meliloti to PHZ, most likely serving as barriers that reduce the amount of PHZ transported inside the cell. IMPORTANCE Many bacteria produce antimicrobial peptides to eliminate competitors and create an exclusive niche. These peptides act either by membrane disruption or by inhibiting essential intracellular processes. The Achilles' heel of the latter type of antimicrobials is their dependence on transporters to enter susceptible cells. Transporter inactivation results in resistance. Here, we show that a rhizobial ribosome-targeting peptide, phazolicin (PHZ), uses two different transporters, BacA and YejABEF, to enter the cells of a symbiotic bacterium, Sinorhizobium meliloti. This dual-entry mode dramatically reduces the probability of the appearance of PHZ-resistant mutants. Since these transporters are also crucial for S. meliloti symbiotic associations with host plants, their inactivation in natural settings is strongly disfavored, making PHZ an attractive lead for the development of biocontrol agents for agriculture.
Collapse
|
40
|
HexSDF Is Required for Synthesis of a Novel Glycolipid That Mediates Daptomycin and Bacitracin Resistance in C. difficile. mBio 2023; 14:e0339722. [PMID: 36786594 PMCID: PMC10128005 DOI: 10.1128/mbio.03397-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Clostridioides difficile is a Gram-positive opportunistic pathogen responsible for 250,000 hospital-associated infections, 12,000 hospital-associated deaths, and $1 billion in medical costs in the United States each year. There has been recent interest in using a daptomycin analog, surotomycin, to treat C. difficile infections. Daptomycin interacts with phosphatidylglycerol and lipid II to disrupt the membrane and halt peptidoglycan synthesis. C. difficile has an unusual lipid membrane composition, as it has no phosphatidylserine or phosphatidylethanolamine, and ~50% of its membrane is composed of glycolipids, including the unique C. difficile lipid aminohexosyl-hexosyldiradylglycerol (HNHDRG). We identified a two-component system (TCS), HexRK, that is required for C. difficile resistance to daptomycin. Using transcriptome sequencing (RNA-seq), we found that HexRK regulates expression of hexSDF, a three-gene operon of unknown function. Based on bioinformatic predictions, hexS encodes a monogalactosyldiacylglycerol synthase, hexD encodes a polysaccharide deacetylase, and hexF encodes an MprF-like flippase. Deletion of hexRK leads to a 4-fold decrease in daptomycin MIC, and that deletion of hexSDF leads to an 8- to 16-fold decrease in daptomycin MIC. The ΔhexSDF mutant is also 4-fold less resistant to bacitracin but no other cell wall-active antibiotics. Our data indicate that in the absence of HexSDF, the phospholipid membrane composition is altered. In wild-type (WT) C. difficile, the unique glycolipid HNHDRG makes up ~17% of the lipids in the membrane. However, in a ΔhexSDF mutant, HNHDRG is completely absent. While it is unclear how HNHDRG contributes to daptomycin resistance, the requirement for bacitracin resistance suggests it has a general role in cell membrane biogenesis. IMPORTANCE Clostridioides difficile is a major cause of hospital-acquired diarrhea and represents an urgent concern due to the prevalence of antibiotic resistance and the rate of recurrent infections. Little is understood about C. difficile membrane lipids, but a unique glycolipid, HNHDRG, has been previously identified in C. difficile and, currently, has not been identified in other organisms. Here, we show that HexSDF and HexRK are required for synthesis of HNHDRG and that production of HNHDRG impacts resistance to daptomycin and bacitracin.
Collapse
|
41
|
Voedts H, Kennedy SP, Sezonov G, Arthur M, Hugonnet JE. Genome-wide identification of genes required for alternative peptidoglycan cross-linking in Escherichia coli revealed unexpected impacts of β-lactams. Nat Commun 2022; 13:7962. [PMID: 36575173 PMCID: PMC9794725 DOI: 10.1038/s41467-022-35528-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/06/2022] [Indexed: 12/28/2022] Open
Abstract
The D,D-transpeptidase activity of penicillin-binding proteins (PBPs) is the well-known primary target of β-lactam antibiotics that block peptidoglycan polymerization. β-lactam-induced bacterial killing involves complex downstream responses whose causes and consequences are difficult to resolve. Here, we use the functional replacement of PBPs by a β-lactam-insensitive L,D-transpeptidase to identify genes essential to mitigate the effects of PBP inactivation by β-lactams in actively dividing bacteria. The functions of the 179 conditionally essential genes identified by this approach extend far beyond L,D-transpeptidase partners for peptidoglycan polymerization to include proteins involved in stress response and in the assembly of outer membrane polymers. The unsuspected effects of β-lactams include loss of the lipoprotein-mediated covalent bond that links the outer membrane to the peptidoglycan, destabilization of the cell envelope in spite of effective peptidoglycan cross-linking, and increased permeability of the outer membrane. The latter effect indicates that the mode of action of β-lactams involves self-promoted penetration through the outer membrane.
Collapse
Affiliation(s)
- Henri Voedts
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| | - Sean P. Kennedy
- Institut Pasteur, Université Paris Cité, Département Biologie Computationnelle, F-75015 Paris, France
| | - Guennadi Sezonov
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| | - Michel Arthur
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| | - Jean-Emmanuel Hugonnet
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| |
Collapse
|
42
|
Karash S, Jiang T, Kwon YM. Genome-wide characterization of Salmonella Typhimurium genes required for the fitness under iron restriction. BMC Genom Data 2022; 23:55. [PMID: 35869435 PMCID: PMC9308263 DOI: 10.1186/s12863-022-01069-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 06/28/2022] [Indexed: 11/24/2022] Open
Abstract
Background Iron is a crucial element for bacterial survival and virulence. During Salmonella infection, the host utilizes a variety of mechanisms to starve the pathogen from iron. However, Salmonella activates distinctive defense mechanisms to acquire iron and survive in iron-restricted host environments. Yet, the comprehensive set of the conditionally essential genes that underpin Salmonella survival under iron-restricted niches has not been fully explored. Results Here, we employed transposon sequencing (Tn-seq) method for high-resolution elucidation of the genes in Salmonella Typhimurium (S. Typhimurium) 14028S strain required for the growth under the in vitro conditions with four different levels of iron restriction achieved by iron chelator 2,2′-dipyridyl (Dip): mild (100 and 150 μM), moderate (250 μM) and severe iron restriction (400 μM). We found that the fitness of the mutants reduced significantly for 28 genes, suggesting the importance of these genes for the growth under iron restriction. These genes include sufABCDSE, iron transport fepD, siderophore tonB, sigma factor E ropE, phosphate transport pstAB, and zinc exporter zntA. The siderophore gene tonB was required in mild and moderate iron-restricted conditions, but it became dispensable in severe iron-restricted conditions. Remarkably, rpoE was required in moderate and severe iron restrictions, leading to complete attenuation of the mutant under these conditions. We also identified 30 genes for which the deletion of the genes resulted in increased fitness under iron-restricted conditions. Conclusions The findings broaden our knowledge of how S. Typhimurium survives in iron-deficient environments, which could be utilized for the development of new therapeutic strategies targeting the pathways vital for iron metabolism, trafficking, and scavenging. Supplementary Information The online version contains supplementary material available at 10.1186/s12863-022-01069-3.
Collapse
|
43
|
Belanger CR, Dostert M, Blimkie TM, Lee AHY, Dhillon BK, Wu BC, Akhoundsadegh N, Rahanjam N, Castillo-Arnemann J, Falsafi R, Pletzer D, Haney CH, Hancock REW. Surviving the host: Microbial metabolic genes required for growth of Pseudomonas aeruginosa in physiologically-relevant conditions. Front Microbiol 2022; 13:1055512. [PMID: 36504765 PMCID: PMC9732424 DOI: 10.3389/fmicb.2022.1055512] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/31/2022] [Indexed: 11/27/2022] Open
Abstract
Pseudomonas aeruginosa, like other pathogens, adapts to the limiting nutritional environment of the host by altering patterns of gene expression and utilizing alternative pathways required for survival. Understanding the genes essential for survival in the host gives insight into pathways that this organism requires during infection and has the potential to identify better ways to treat infections. Here, we used a saturated transposon insertion mutant pool of P. aeruginosa strain PAO1 and transposon insertion sequencing (Tn-Seq), to identify genes conditionally important for survival under conditions mimicking the environment of a nosocomial infection. Conditions tested included tissue culture medium with and without human serum, a murine abscess model, and a human skin organoid model. Genes known to be upregulated during infections, as well as those involved in nucleotide metabolism, and cobalamin (vitamin B12) biosynthesis, etc., were required for survival in vivo- and in host mimicking conditions, but not in nutrient rich lab medium, Mueller Hinton broth (MHB). Correspondingly, mutants in genes encoding proteins of nucleotide and cobalamin metabolism pathways were shown to have growth defects under physiologically-relevant media conditions, in vivo, and in vivo-like models, and were downregulated in expression under these conditions, when compared to MHB. This study provides evidence for the relevance of studying P. aeruginosa fitness in physiologically-relevant host mimicking conditions and identified metabolic pathways that represent potential novel targets for alternative therapies.
Collapse
Affiliation(s)
- Corrie R. Belanger
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Melanie Dostert
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy Huei-Yi Lee
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada,Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Bhavjinder Kaur Dhillon
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Bing Catherine Wu
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Noushin Akhoundsadegh
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Negin Rahanjam
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Javier Castillo-Arnemann
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Reza Falsafi
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Pletzer
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada,Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cara H. Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada,*Correspondence: Robert E. W. Hancock,
| |
Collapse
|
44
|
Dostert M, Belanger CR, Pedraz L, Alford MA, Blimkie TM, Falsafi RF, Bains M, Dhillon BK, Haney CH, Lee AH, Hancock REW. BosR: A novel biofilm-specific regulator in Pseudomonas aeruginosa. Front Microbiol 2022; 13:1021021. [PMID: 36312952 PMCID: PMC9611778 DOI: 10.3389/fmicb.2022.1021021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Biofilms are the most common cause of bacterial infections in humans and notoriously hard to treat due to their ability to withstand antibiotics and host immune defenses. To overcome the current lack of effective antibiofilm therapies and guide future design, the identification of novel biofilm-specific gene targets is crucial. In this regard, transcriptional regulators have been proposed as promising targets for antimicrobial drug design. Therefore, a Transposon insertion sequencing approach was employed to systematically identify regulators phenotypically affecting biofilm growth in Pseudomonas aeruginosa PA14 using the TnSeq analysis tools Bio-TraDIS and TRANSIT. A screen of a pool of 300,000 transposon insertion mutants identified 349 genes involved in biofilm growth on hydroxyapatite, including 47 regulators. Detection of 19 regulatory genes participating in well-established biofilm pathways validated the results. An additional 28 novel prospective biofilm regulators suggested the requirement for multiple one-component transcriptional regulators. Biofilm-defective phenotypes were confirmed for five one-component transcriptional regulators and a protein kinase, which did not affect motility phenotypes. The one-component transcriptional regulator bosR displayed a conserved role in P. aeruginosa biofilm growth since its ortholog in P. aeruginosa strain PAO1 was also required for biofilm growth. Microscopic analysis of a chromosomal deletion mutant of bosR confirmed the role of this regulator in biofilm growth. Overall, our results highlighted that the gene network driving biofilm growth is complex and involves regulators beyond the primarily studied groups of two-component systems and cyclic diguanylate signaling proteins. Furthermore, biofilm-specific regulators, such as bosR, might constitute prospective new drug targets to overcome biofilm infections.
Collapse
Affiliation(s)
- Melanie Dostert
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Corrie R. Belanger
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Lucas Pedraz
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Morgan A. Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Reza F. Falsafi
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Bhavjinder Kaur Dhillon
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Cara H. Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy H. Lee
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Robert E. W. Hancock,
| |
Collapse
|
45
|
Fischer MA, Engelgeh T, Rothe P, Fuchs S, Thürmer A, Halbedel S. Listeria monocytogenes genes supporting growth under standard laboratory cultivation conditions and during macrophage infection. Genome Res 2022; 32:1711-1726. [PMID: 36114002 PMCID: PMC9528990 DOI: 10.1101/gr.276747.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/04/2022] [Indexed: 11/24/2022]
Abstract
The Gram-positive bacterium Listeria monocytogenes occurs widespread in the environment and infects humans when ingested along with contaminated food. Such infections are particularly dangerous for risk group patients, for whom they represent a life-threatening disease. To invent novel strategies to control contamination and disease, it is important to identify those cellular processes that maintain pathogen growth inside and outside the host. Here, we have applied transposon insertion sequencing (Tn-Seq) to L. monocytogenes for the identification of such processes on a genome-wide scale. Our approach identified 394 open reading frames that are required for growth under standard laboratory conditions and 42 further genes, which become necessary during intracellular growth in macrophages. Most of these genes encode components of the translation machinery and act in chromosome-related processes, cell division, and biosynthesis of the cellular envelope. Several cofactor biosynthesis pathways and 29 genes with unknown functions are also required for growth, suggesting novel options for the development of antilisterial drugs. Among the genes specifically required during intracellular growth are known virulence factors, genes compensating intracellular auxotrophies, and several cell division genes. Our experiments also highlight the importance of PASTA kinase signaling for general viability and of glycine metabolism and chromosome segregation for efficient intracellular growth of L. monocytogenes.
Collapse
Affiliation(s)
- Martin A Fischer
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| | - Tim Engelgeh
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| | - Patricia Rothe
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| | - Stephan Fuchs
- MF1 Bioinformatic Support, Robert Koch Institute, 13353 Berlin, Germany
| | - Andrea Thürmer
- MF2 Genome Sequencing, Robert Koch Institute, 13353 Berlin, Germany
| | - Sven Halbedel
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, 38855 Wernigerode, Germany
| |
Collapse
|
46
|
Gibson AJ, Stiens J, Passmore IJ, Faulkner V, Miculob J, Willcocks S, Coad M, Berg S, Werling D, Wren BW, Nobeli I, Villarreal-Ramos B, Kendall SL. Defining the Genes Required for Survival of Mycobacterium bovis in the Bovine Host Offers Novel Insights into the Genetic Basis of Survival of Pathogenic Mycobacteria. mBio 2022; 13:e0067222. [PMID: 35862770 PMCID: PMC9426507 DOI: 10.1128/mbio.00672-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/22/2022] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis has severe impacts on both humans and animals. Understanding the genetic basis of survival of both Mycobacterium tuberculosis, the human-adapted species, and Mycobacterium bovis, the animal-adapted species, is crucial to deciphering the biology of both pathogens. There are several studies that identify the genes required for survival of M. tuberculosis in vivo using mouse models; however, there are currently no studies probing the genetic basis of survival of M. bovis in vivo. In this study, we utilize transposon insertion sequencing in M. bovis AF2122/97 to determine the genes required for survival in cattle. We identify genes encoding established mycobacterial virulence functions such as the ESX-1 secretion system, phthiocerol dimycocerosate (PDIM) synthesis, mycobactin synthesis, and cholesterol catabolism that are required in vivo. We show that, as in M. tuberculosis H37Rv, phoPR is required by M. bovis AF2122/97 in vivo despite the known defect in signaling through this system. Comparison to studies performed in species that are able to use carbohydrates as an energy source, such as M. bovis BCG and M. tuberculosis, suggests that there are differences in the requirement for genes involved in cholesterol import (mce4 operon) and oxidation (hsd). We report a good correlation with existing mycobacterial virulence functions but also find several novel virulence factors, including genes involved in protein mannosylation, aspartate metabolism, and glycerol-phosphate metabolism. These findings further extend our knowledge of the genetic basis of survival in vivo in bacteria that cause tuberculosis and provide insight for the development of novel diagnostics and therapeutics. IMPORTANCE This is the first report of the genetic requirements of an animal-adapted member of the Mycobacterium tuberculosis complex (MTBC) in a natural host. M. bovis has devastating impacts on cattle, and bovine tuberculosis is a considerable economic, animal welfare, and public health concern. The data highlight the importance of mycobacterial cholesterol catabolism and identify several new virulence factors. Additionally, the work informs the development of novel differential diagnostics and therapeutics for TB in both human and animal populations.
Collapse
Affiliation(s)
- Amanda J. Gibson
- Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Jennifer Stiens
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, United Kingdom
| | - Ian J. Passmore
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Valwynne Faulkner
- Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Josephous Miculob
- Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Sam Willcocks
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael Coad
- Animal and Plant Health Agency, Addlestone, Surrey, United Kingdom
| | - Stefan Berg
- Animal and Plant Health Agency, Addlestone, Surrey, United Kingdom
| | - Dirk Werling
- Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Brendan W. Wren
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Irene Nobeli
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck, University of London, London, United Kingdom
| | | | - Sharon L. Kendall
- Centre for Emerging, Endemic and Exotic Diseases, Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, United Kingdom
| |
Collapse
|
47
|
Differential Genetic Strategies of Burkholderia vietnamiensis and Paraburkholderia kururiensis for Root Colonization of Oryza sativa subsp.
japonica
and O. sativa subsp.
indica
, as Revealed by Transposon Mutagenesis Sequencing. Appl Environ Microbiol 2022; 88:e0064222. [DOI: 10.1128/aem.00642-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Burkholderiaceae
are frequent and abundant colonizers of the rice rhizosphere and interesting candidates to investigate for growth promotion. Species of
Paraburkholderia
have repeatedly been described to stimulate plant growth.
Collapse
|
48
|
Genomic Analyses Identify Manganese Homeostasis as a Driver of Group B Streptococcal Vaginal Colonization. mBio 2022; 13:e0098522. [PMID: 35658538 PMCID: PMC9239048 DOI: 10.1128/mbio.00985-22] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Group B Streptococcus (GBS) is associated with severe infections in utero and in newborn populations, including pneumonia, sepsis, and meningitis. GBS vaginal colonization of the pregnant mother is an important prerequisite for transmission to the newborn and the development of neonatal invasive disease; however, our understanding of the factors required for GBS persistence and ascension in the female reproductive tract (FRT) remains limited. Here, we utilized a GBS mariner transposon (Krmit) mutant library previously developed by our group and identified underrepresented mutations in 535 genes that contribute to survival within the vaginal lumen and colonization of vaginal, cervical, and uterine tissues. From these mutants, we identified 47 genes that were underrepresented in all samples collected, including mtsA, a component of the mtsABC locus, encoding a putative manganese (Mn2+)-dependent ATP-binding cassette transporter. RNA sequencing analysis of GBS recovered from the vaginal tract also revealed a robust increase of mtsA expression during vaginal colonization. We engineered an ΔmtsA mutant strain and found by using inductively coupled plasma mass spectrometry that it exhibited decreased concentrations of intracellular Mn2+, confirming its involvement in Mn2+ acquisition. The ΔmtsA mutant was significantly more susceptible to the metal chelator calprotectin and to oxidative stressors, including both H2O2 and paraquat, than wild-type (WT) GBS. We further observed that the ΔmtsA mutant strain exhibited a significant fitness defect in comparison to WT GBS in vivo by using a murine model of vaginal colonization. Taken together, these data suggest that Mn2+ homeostasis is an important process contributing to GBS survival in the FRT.
Collapse
|
49
|
Akusobi C, Benghomari BS, Zhu J, Wolf ID, Singhvi S, Dulberger CL, Ioerger TR, Rubin EJ. Transposon mutagenesis in Mycobacterium abscessus identifies an essential penicillin-binding protein involved in septal peptidoglycan synthesis and antibiotic sensitivity. eLife 2022; 11:71947. [PMID: 35659317 PMCID: PMC9170245 DOI: 10.7554/elife.71947] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 05/24/2022] [Indexed: 02/06/2023] Open
Abstract
Mycobacterium abscessus (Mab) is a rapidly growing non-tuberculous mycobacterium (NTM) that causes a wide range of infections. Treatment of Mab infections is difficult because the bacterium is intrinsically resistant to many classes of antibiotics. Developing new and effective treatments against Mab requires a better understanding of the unique vulnerabilities that can be targeted for future drug development. To achieve this, we identified essential genes in Mab by conducting transposon sequencing (TnSeq) on the reference Mab strain ATCC 19977. We generated ~51,000 unique transposon mutants and used this high-density library to identify 362 essential genes for in vitro growth. To investigate species-specific vulnerabilities in Mab, we further characterized MAB_3167c, a predicted penicillin-binding protein and hypothetical lipoprotein (PBP-lipo) that is essential in Mab and non-essential in Mycobacterium tuberculosis (Mtb). We found that PBP-lipo primarily localizes to the subpolar region and later to the septum as cells prepare to divide. Depletion of Mab PBP-lipo causes cells to elongate, develop ectopic branches, and form multiple septa. Knockdown of PBP-lipo along with PbpB, DacB1, and a carboxypeptidase, MAB_0519 lead to synergistic growth arrest. In contrast, these genetic interactions were absent in the Mtb model organism, Mycobacterium smegmatis, indicating that the PBP-lipo homologs in the two species exist in distinct genetic networks. Finally, repressing PBP-lipo sensitized the reference strain and 11 Mab clinical isolates to several classes of antibiotics, including the β-lactams, ampicillin, and amoxicillin by greater than 128-fold. Altogether, this study presents PBP-lipo as a key enzyme to study Mab-specific processes in cell wall synthesis and importantly positions PBP-lipo as an attractive drug target to treat Mab infections.
Collapse
Affiliation(s)
- Chidiebere Akusobi
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| | | | - Junhao Zhu
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Ian D Wolf
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Shreya Singhvi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Charles L Dulberger
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Thomas R Ioerger
- Department of Computer Science and Engineering, Texas A&M University, College Station, United States
| | - Eric J Rubin
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| |
Collapse
|
50
|
Morinière L, Mirabel L, Gueguen E, Bertolla F. A Comprehensive Overview of the Genes and Functions Required for Lettuce Infection by the Hemibiotrophic Phytopathogen Xanthomonas hortorum pv. vitians. mSystems 2022; 7:e0129021. [PMID: 35311560 PMCID: PMC9040725 DOI: 10.1128/msystems.01290-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/07/2022] [Indexed: 12/25/2022] Open
Abstract
The successful infection of a host plant by a phytopathogenic bacterium depends on a finely tuned molecular cross talk between the two partners. Thanks to transposon insertion sequencing techniques (Tn-seq), whole genomes can now be assessed to determine which genes are important for the fitness of several plant-associated bacteria in planta. Despite its agricultural relevance, the dynamic molecular interaction established between the foliar hemibiotrophic phytopathogen Xanthomonas hortorum pv. vitians and its host, lettuce (Lactuca sativa), remains completely unknown. To decipher the genes and functions mobilized by the pathogen throughout the infection process, we conducted a Tn-seq experiment in lettuce leaves to mimic the selective pressure occurring during natural infection. This genome-wide screening identified 170 genes whose disruption caused serious fitness defects in lettuce. A thorough examination of these genes using comparative genomics and gene set enrichment analyses highlighted that several functions and pathways were highly critical for the pathogen's survival. Numerous genes involved in amino acid, nucleic acid, and exopolysaccharide biosynthesis were critical. The xps type II secretion system operon, a few TonB-dependent transporters involved in carbohydrate or siderophore scavenging, and multiple genes of the carbohydrate catabolism pathways were also critical, emphasizing the importance of nutrition systems in a nutrient-limited environment. Finally, several genes implied in camouflage from the plant immune system and resistance to immunity-induced oxidative stress were strongly involved in host colonization. As a whole, these results highlight some of the central metabolic pathways and cellular functions critical for Xanthomonas host adaptation and pathogenesis. IMPORTANCE Xanthomonas hortorum was recently the subject of renewed interest, as several studies highlighted that its members were responsible for diseases in a wide range of plant species, including crops of agricultural relevance (e.g., tomato and carrot). Among X. hortorum variants, X. hortorum pv. vitians is a reemerging foliar hemibiotrophic phytopathogen responsible for severe outbreaks of bacterial leaf spot of lettuce all around the world. Despite recent findings, sustainable and practical means of disease control remain to be developed. Understanding the host-pathogen interaction from a molecular perspective is crucial to support these efforts. The genes and functions mobilized by X. hortorum pv. vitians during its interaction with lettuce had never been investigated. Our study sheds light on these processes by screening the whole pathogen genome for genes critical for its fitness during the infection process, using transposon insertion sequencing and comparative genomics.
Collapse
Affiliation(s)
- Lucas Morinière
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
| | - Laurène Mirabel
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
| | - Erwan Gueguen
- Université Lyon, Université Claude Bernard Lyon 1, INSA, CNRS, UMR Microbiologie, Adaptation, Pathogénie, Villeurbanne, France
| | - Franck Bertolla
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
| |
Collapse
|