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Tao Y, Zheng D, Zou W, Guo T, Liao G, Zhou W. Targeting the cysteine biosynthesis pathway in microorganisms: Mechanism, structure, and drug discovery. Eur J Med Chem 2024; 271:116461. [PMID: 38691891 DOI: 10.1016/j.ejmech.2024.116461] [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: 02/01/2024] [Revised: 04/16/2024] [Accepted: 04/27/2024] [Indexed: 05/03/2024]
Abstract
Owing to the global health crisis of resistant pathogenic infections, researchers are emphasizing the importance of novel prevention and control strategies. Existing antimicrobial drugs predominantly target a few pathways, and their widespread use has pervasively increased drug resistance. Therefore, it is imperative to develop new antimicrobial drugs with novel targets and chemical structures. The de novo cysteine biosynthesis pathway, one of the microbial metabolic pathways, plays a crucial role in pathogenicity and drug resistance. This pathway notably differs from that in humans, thereby representing an unexplored target for developing antimicrobial drugs. Herein, we have presented an overview of cysteine biosynthesis pathways and their roles in the pathogenicity of various microorganisms. Additionally, we have investigated the structure and function of enzymes involved in these pathways as well as have discussed drug design strategies and structure-activity relationships of the enzyme inhibitors. This review provides valuable insights for developing novel antimicrobials and offers new avenues to combat drug resistance.
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Affiliation(s)
- Ying Tao
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Dandan Zheng
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Wei Zou
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Ting Guo
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Guojian Liao
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China.
| | - Wei Zhou
- State Key Laboratory of Resource Insects, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China.
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2
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Mallikaarachchi KS, Huang JL, Madras S, Cuellar RA, Huang Z, Gega A, Rathnayaka-Mudiyanselage IW, Al-Husini N, Saldaña-Rivera N, Ma LH, Ng E, Chen JC, Schrader JM. Sinorhizobium meliloti BR-bodies promote fitness during host colonization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.05.588320. [PMID: 38617242 PMCID: PMC11014517 DOI: 10.1101/2024.04.05.588320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Biomolecular condensates, such as the nucleoli or P-bodies, are non-membrane-bound assemblies of proteins and nucleic acids that facilitate specific cellular processes. Like eukaryotic P-bodies, the recently discovered bacterial ribonucleoprotein bodies (BR-bodies) organize the mRNA decay machinery, yet the similarities in molecular and cellular functions across species have been poorly explored. Here, we examine the functions of BR-bodies in the nitrogen-fixing endosymbiont Sinorhizobium meliloti, which colonizes the roots of compatible legume plants. Assembly of BR-bodies into visible foci in S. meliloti cells requires the C-terminal intrinsically disordered region (IDR) of RNase E, and foci fusion is readily observed in vivo, suggesting they are liquid-like condensates that form via mRNA sequestration. Using Rif-seq to measure mRNA lifetimes, we found a global slowdown in mRNA decay in a mutant deficient in BR-bodies, indicating that compartmentalization of the degradation machinery promotes efficient mRNA turnover. While BR-bodies are constitutively present during exponential growth, the abundance of BR-bodies increases upon cell stress, whereby they promote stress resistance. Finally, using Medicago truncatula as host, we show that BR-bodies enhance competitiveness during colonization and appear to be required for effective symbiosis, as mutants without BR-bodies failed to stimulate plant growth. These results suggest that BR-bodies provide a fitness advantage for bacteria during infection, perhaps by enabling better resistance against the host immune response.
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Affiliation(s)
| | | | | | - Rodrigo A. Cuellar
- Department of Biology, San Francisco State University
- Current affiliation: University of Wisconsin, Madison
| | | | - Alisa Gega
- Department of Biological Sciences, Wayne State University
- Current affiliation: University of Toledo Medical School, Toledo
| | | | | | | | - Loi H. Ma
- Department of Biology, San Francisco State University
| | - Eric Ng
- Department of Biology, San Francisco State University
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3
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Adherence enables Neisseria gonorrhoeae to overcome zinc limitation imposed by nutritional immunity proteins. Infect Immun 2022; 90:e0000922. [PMID: 35156850 DOI: 10.1128/iai.00009-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria gonorrhoeae (Gc) must overcome limitation of metals such as zinc to colonize mucosal surfaces in its obligate human host. While the zinc-binding nutritional immunity proteins calprotectin (S100A8/A9) and psoriasin (S100A7) are abundant in human cervicovaginal lavage fluid, Gc possesses TonB-dependent transporters TdfH and TdfJ that bind and extract zinc from the human version of these proteins, respectively. Here we investigated the contribution of zinc acquisition to Gc infection of epithelial cells of the female genital tract. We found that TdfH and TdfJ were dispensable for survival of strain FA1090 Gc that were associated with Ect1 human immortalized epithelial cells, when zinc was limited by calprotectin and psoriasin. In contrast, suspension-grown bacteria declined in viability under the same conditions. Exposure to murine calprotectin, which Gc cannot use as a zinc source, similarly reduced survival of suspension-grown Gc, but not Ect1-associated Gc. We ruled out epithelial cells as a contributor to the enhanced growth of cell-associated Gc under zinc limitation. Instead, we found that attachment to glass was sufficient to enhance bacterial growth when zinc was sequestered. We compared the transcriptional profiles of WT Gc adherent to glass coverslips or in suspension, when zinc was sequestered with murine calprotectin or provided in excess, from which we identified open reading frames that were increased by zinc sequestration in adherent Gc. One of these, ZnuA, was necessary but not sufficient for survival of Gc under zinc-limiting conditions. These results show that adherence protects Gc from zinc-dependent growth restriction by host nutritional immunity proteins.
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4
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van de Beek D, Brouwer MC, Koedel U, Wall EC. Community-acquired bacterial meningitis. Lancet 2021; 398:1171-1183. [PMID: 34303412 DOI: 10.1016/s0140-6736(21)00883-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/25/2021] [Accepted: 04/07/2021] [Indexed: 12/19/2022]
Abstract
Progress has been made in the prevention and treatment of community-acquired bacterial meningitis during the past three decades but the burden of the disease remains high globally. Conjugate vaccines against the three most common causative pathogens (Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae) have reduced the incidence of disease, but with the replacement by non-vaccine pneumococcal serotypes and the emergence of bacterial strains with reduced susceptibility to antimicrobial treatment, meningitis continues to pose a major health challenge worldwide. In patients presenting with bacterial meningitis, typical clinical characteristics (such as the classic triad of neck stiffness, fever, and an altered mental status) might be absent and cerebrospinal fluid examination for biochemistry, microscopy, culture, and PCR to identify bacterial DNA are essential for the diagnosis. Multiplex PCR point-of-care panels in cerebrospinal fluid show promise in accelerating the diagnosis, but diagnostic accuracy studies to justify routine implementation are scarce and randomised, controlled studies are absent. Early administration of antimicrobial treatment (within 1 hour of presentation) improves outcomes and needs to be adjusted according to local emergence of drug resistance. Adjunctive dexamethasone treatment has proven efficacy beyond the neonatal age but only in patients from high-income countries. Further progress can be expected from implementing preventive measures, especially the development of new vaccines, implementation of hospital protocols aimed at early treatment, and new treatments targeting checkpoints of the inflammatory cascade.
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Affiliation(s)
- Diederik van de Beek
- Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef, Amsterdam, Netherlands.
| | - Matthijs C Brouwer
- Department of Neurology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Meibergdreef, Amsterdam, Netherlands
| | - Uwe Koedel
- Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Emma C Wall
- Research Department of Infection, University College London, London, UK; Francis Crick Institute, London, UK
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5
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Westermann AJ, Vogel J. Cross-species RNA-seq for deciphering host-microbe interactions. Nat Rev Genet 2021; 22:361-378. [PMID: 33597744 DOI: 10.1038/s41576-021-00326-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2021] [Indexed: 02/08/2023]
Abstract
The human body is constantly exposed to microorganisms, which entails manifold interactions between human cells and diverse commensal or pathogenic bacteria. The cellular states of the interacting cells are decisive for the outcome of these encounters such as whether bacterial virulence programmes and host defence or tolerance mechanisms are induced. This Review summarizes how next-generation RNA sequencing (RNA-seq) has become a primary technology to study host-microbe interactions with high resolution, improving our understanding of the physiological consequences and the mechanisms at play. We illustrate how the discriminatory power and sensitivity of RNA-seq helps to dissect increasingly complex cellular interactions in time and space down to the single-cell level. We also outline how future transcriptomics may answer currently open questions in host-microbe interactions and inform treatment schemes for microbial disorders.
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Affiliation(s)
- Alexander J Westermann
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany. .,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany. .,Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
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6
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Abstract
The goal of genomics and systems biology is to understand how complex systems of factors assemble into pathways and structures that combine to form living organisms. Great advances in understanding biological processes result from determining the function of individual genes, a process that has classically relied on characterizing single mutations. Advances in DNA sequencing has made available the complete set of genetic instructions for an astonishing and growing number of species. To understand the function of this ever-increasing number of genes, a high-throughput method was developed that in a single experiment can measure the function of genes across the genome of an organism. This occurred approximately 10 years ago, when high-throughput DNA sequencing was combined with advances in transposon-mediated mutagenesis in a method termed transposon insertion sequencing (TIS). In the subsequent years, TIS succeeded in addressing fundamental questions regarding the genes of bacteria, many of which have been shown to play central roles in bacterial infections that result in major human diseases. The field of TIS has matured and resulted in studies of hundreds of species that include significant innovations with a number of transposons. Here, we summarize a number of TIS experiments to provide an understanding of the method and explanation of approaches that are instructive when designing a study. Importantly, we emphasize critical aspects of a TIS experiment and highlight the extension and applicability of TIS into nonbacterial species such as yeast.
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Affiliation(s)
- Tim van Opijnen
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA;
| | - Henry L Levin
- Section on Eukaryotic Transposable Elements, Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA;
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7
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Cain AK, Barquist L, Goodman AL, Paulsen IT, Parkhill J, van Opijnen T. A decade of advances in transposon-insertion sequencing. Nat Rev Genet 2020; 21:526-540. [PMID: 32533119 PMCID: PMC7291929 DOI: 10.1038/s41576-020-0244-x] [Citation(s) in RCA: 203] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2020] [Indexed: 01/12/2023]
Abstract
It has been 10 years since the introduction of modern transposon-insertion sequencing (TIS) methods, which combine genome-wide transposon mutagenesis with high-throughput sequencing to estimate the fitness contribution or essentiality of each genetic component in a bacterial genome. Four TIS variations were published in 2009: transposon sequencing (Tn-Seq), transposon-directed insertion site sequencing (TraDIS), insertion sequencing (INSeq) and high-throughput insertion tracking by deep sequencing (HITS). TIS has since become an important tool for molecular microbiologists, being one of the few genome-wide techniques that directly links phenotype to genotype and ultimately can assign gene function. In this Review, we discuss the recent applications of TIS to answer overarching biological questions. We explore emerging and multidisciplinary methods that build on TIS, with an eye towards future applications. In this Review, several experts discuss progress in the decade since the development of transposon-based approaches for bacterial genetic screens. They describe how advances in both experimental technologies and analytical strategies are resulting in insights into diverse biological processes.
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Affiliation(s)
- Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany.,Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Andrew L Goodman
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA.,Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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8
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Righetti F, Materne SL, Boss J, Eichner H, Charpentier E, Loh E. Characterization of a transcriptional TPP riboswitch in the human pathogen Neisseria meningitidis. RNA Biol 2020; 17:718-730. [PMID: 32079473 PMCID: PMC7237195 DOI: 10.1080/15476286.2020.1727188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Increasing evidence has demonstrated that regulatory RNA elements such as riboswitches (RS) play a pivotal role in the fine-tuning of bacterial gene expression. In this study, we investigated and characterized a novel transcriptional thiamine pyrophosphate (TPP) RS in the obligate human pathogen N. meningitidis MC58 (serogroup B). This RS is located in the 5´ untranslated region upstream of thiC gene, encoding a protein involved in TPP biosynthesis, an essential cofactor for all living beings. Primer extension revealed the transcriptional start site of thiC. Northern blot analysis of thiC mRNA and reporter gene studies confirmed the presence of an active TPP-sensing RS. Expression patterns of the wild-type RS and site-specific mutants showed that it is an OFF switch that controls transcription elongation of thiC mRNA. Interestingly, the regulatory mechanism of the meningococcal thiC RS resembles the Gram-positive Bacillus subtilis thiC RS rather than the Gram-negative Escherichia coli thiC RS. Therefore, the meningococcal thiC RS represents a rare example of transcriptional RS in a Gram-negative bacterium. We further observed that the RS is actively involved in modulating gene expression in response to different growth media and to supplemented bacterial and eukaryotic cell lysates as possible sources of nutrients in the nasopharynx. Our results suggest that RS-mediated gene regulation could influence meningococcal fitness, through the fine-tuning of biosynthesis and scavenging of nutrients and cofactors, such as thiamine.
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Affiliation(s)
- Francesco Righetti
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Solange Lise Materne
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - John Boss
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Hannes Eichner
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Emmanuelle Charpentier
- Max Planck Unit for the Science of Pathogens, Berlin, Germany.,Department of Regulation in Infection Biology, Max Planck Institute for Infection Biology, Berlin, Germany.,Institute for Biology, Humboldt University, Berlin, Germany.,Department of Regulation in Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Edmund Loh
- Department of Microbiology, Tumor- and Cell Biology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden.,SCELSE, Nanyang Technological University, Singapore, Singapore
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9
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Contribution of σ 70 and σ N Factors to Expression of Class II pilE in Neisseria meningitidis. J Bacteriol 2019; 201:JB.00170-19. [PMID: 31331980 PMCID: PMC6755734 DOI: 10.1128/jb.00170-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 07/16/2019] [Indexed: 02/06/2023] Open
Abstract
Neisseria meningitidis expresses multicomponent organelles called type four pili (Tfp), which are key virulence factors required for attachment to human cells during carriage and disease. Pilin (PilE) is the main component of Tfp, and N. meningitidis isolates either have a class I pilE locus and express pilins that undergo antigenic variation or have a class II pilE locus and express invariant pilins. The transcriptional regulation of class I pilE has been studied in both N. meningitidis and Neisseria gonorrhoeae, while the control of expression of class II pilE has been elucidated in the nonpathogenic species Neisseria elongata However, the factors that govern the regulation of the class II pilE gene in N. meningitidis are not known. In this work, we have bioinformatically and experimentally identified the class II pilE promoter. We confirmed the presence of conserved σ70 and σN-dependent promoters upstream of pilE in a collection of meningococcal genomes and demonstrated that class II pilE expression initiates from the σ70 family-dependent promoter. By deletion or overexpression of sigma factors, we showed that σN, σH, and σE do not affect class II pilin expression. These findings are consistent with a role of the housekeeping σD in expression of this important component of Tfp. Taken together, our data indicate that the σ-dependent network responsible for the expression of class II pilE has been selected to maintain pilE expression, consistent with the essential roles of Tfp in colonization and pathogenesis.IMPORTANCE The type four pilus (Tfp) of Neisseria meningitidis contributes to fundamental processes such as adhesion, transformation, and disease pathology. Meningococci express one of two distinct classes of Tfp (class I or class II), which can be distinguished antigenically or by the major subunit (pilE) locus and its genetic context. The factors that govern transcription of the class II pilE gene are not known, even though it is present in isolates that cause epidemic disease. Here we show that the transcription of class II pilE is maintained throughout growth and under different stress conditions and is driven by a σ70-dependent promoter. This is distinct from Tfp regulation in nonpathogenic Neisseria spp. and may confer an advantage during host-cell interaction and infection.
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10
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Hicks JL, Mullholland CV. Cysteine biosynthesis in Neisseria species. MICROBIOLOGY-SGM 2018; 164:1471-1480. [PMID: 30307392 DOI: 10.1099/mic.0.000728] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The principal mechanism of reducing sulfur into organic compounds is via the synthesis of l-cysteine. Cysteine is used for protein and glutathione synthesis, as well as being the primary sulfur source for a variety of other molecules, such as biotin, coenzyme A, lipoic acid and more. Glutathione and other cysteine derivatives are important for protection against the oxidative stress that pathogenic bacteria such as Neisseria gonorrhoeae and Neisseria meningitidis encounter during infection. With the alarming rise of antibiotic-resistant strains of N. gonorrhoeae, the development of inhibitors for the future treatment of this disease is critical, and targeting cysteine biosynthesis enzymes could be a promising approach for this. Little is known about the transport of sulfate and thiosulfate and subsequent sulfate reduction and incorporation into cysteine in Neisseria species. In this review we investigate cysteine biosynthesis within Neisseria species and examine the differences between species and with other bacteria. Neisseria species exhibit different arrangements of cysteine biosynthesis genes and have slight differences in how they assimilate sulfate and synthesize cysteine, while, most interestingly, N. gonorrhoeae by virtue of a genome deletion, lacks the ability to reduce sulfate to bisulfide for incorporation into cysteine, and as such uses the thiosulfate uptake pathway for the synthesis of cysteine.
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Affiliation(s)
- Joanna L Hicks
- School of Science, University of Waikato, Gate 8 Hillcrest Road, Hamilton, 3216, New Zealand
| | - Claire V Mullholland
- School of Science, University of Waikato, Gate 8 Hillcrest Road, Hamilton, 3216, New Zealand
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11
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Harrison OB, Schoen C, Retchless AC, Wang X, Jolley KA, Bray JE, Maiden MCJ. Neisseria genomics: current status and future perspectives. Pathog Dis 2018; 75:3861976. [PMID: 28591853 PMCID: PMC5827584 DOI: 10.1093/femspd/ftx060] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/05/2017] [Indexed: 12/17/2022] Open
Abstract
High-throughput whole genome sequencing has unlocked a multitude of possibilities enabling members of the Neisseria genus to be examined with unprecedented detail, including the human pathogens Neisseria meningitidis and Neisseria gonorrhoeae. To maximise the potential benefit of this for public health, it is becoming increasingly important to ensure that this plethora of data are adequately stored, disseminated and made readily accessible. Investigations facilitating cross-species comparisons as well as the analysis of global datasets will allow differences among and within species and across geographic locations and different times to be identified, improving our understanding of the distinct phenotypes observed. Recent advances in high-throughput platforms that measure the transcriptome, proteome and/or epigenome are also becoming increasingly employed to explore the complexities of Neisseria biology. An integrated approach to the analysis of these is essential to fully understand the impact these may have in the Neisseria genus. This article reviews the current status of some of the tools available for next generation sequence analysis at the dawn of the ‘post-genomic’ era.
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Affiliation(s)
| | - Christoph Schoen
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg 97080, Germany
| | - Adam C Retchless
- Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Xin Wang
- Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Keith A Jolley
- Department of Zoology, University of Oxford, Oxford OX1 3SY, UK
| | - James E Bray
- Department of Zoology, University of Oxford, Oxford OX1 3SY, UK
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12
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O'Toole RF. Establishing the critical role of peripheral blood vessel colonisation by Neisseria meningitidis in invasive meningococcal disease. Virulence 2018; 8:1513-1515. [PMID: 29219762 DOI: 10.1080/21505594.2017.1415191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
In this issue of Virulence, Capel and colleagues describe the use of a unique humanised mouse model to elucidate specific interactions between Neisseria meningitidis and human endothelial cells during blood-borne infection in vivo. Here, a number of the key findings from their study and their implications for our understanding of invasive meningococcal disease are explored.
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Affiliation(s)
- Ronan F O'Toole
- a School of Medicine, Faculty of Health, University of Tasmania , Tasmania , Australia
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13
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A phylogenetic method to perform genome-wide association studies in microbes that accounts for population structure and recombination. PLoS Comput Biol 2018; 14:e1005958. [PMID: 29401456 PMCID: PMC5814097 DOI: 10.1371/journal.pcbi.1005958] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 02/15/2018] [Accepted: 12/30/2017] [Indexed: 11/28/2022] Open
Abstract
Genome-Wide Association Studies (GWAS) in microbial organisms have the potential to vastly improve the way we understand, manage, and treat infectious diseases. Yet, microbial GWAS methods established thus far remain insufficiently able to capitalise on the growing wealth of bacterial and viral genetic sequence data. Facing clonal population structure and homologous recombination, existing GWAS methods struggle to achieve both the precision necessary to reject spurious findings and the power required to detect associations in microbes. In this paper, we introduce a novel phylogenetic approach that has been tailor-made for microbial GWAS, which is applicable to organisms ranging from purely clonal to frequently recombining, and to both binary and continuous phenotypes. Our approach is robust to the confounding effects of both population structure and recombination, while maintaining high statistical power to detect associations. Thorough testing via application to simulated data provides strong support for the power and specificity of our approach and demonstrates the advantages offered over alternative cluster-based and dimension-reduction methods. Two applications to Neisseria meningitidis illustrate the versatility and potential of our method, confirming previously-identified penicillin resistance loci and resulting in the identification of both well-characterised and novel drivers of invasive disease. Our method is implemented as an open-source R package called treeWAS which is freely available at https://github.com/caitiecollins/treeWAS. Measurable differences often exist within a microbial population, with important ecological or epidemiological consequences. Examples include differences in growth rates, host range, transmissibility, antimicrobial resistance, virulence, etc. Understanding the genetic factors involved in these phenotypic properties is a crucial aim in microbial genomics. A fundamental approach for doing so is to perform a Genome-Wide Association Study (GWAS), where genomes are compared to search for genetic markers systematically correlated with the property of interest. If this strategy were implemented naively in microbes, it could lead to spurious results due to the confounding effects of population structure and recombination. Here we present treeWAS, a new phylogenetic method to perform microbial GWAS that avoids these pitfalls. We show, using simulated datasets, that treeWAS is able to distinguish between genetic markers that are truly associated with the property of interest and those that are not. Furthermore, we demonstrate that treeWAS offers advantages in both sensitivity and specificity over alternative cluster-based and dimension-reduction techniques. We also showcase treeWAS in two applications to real datasets from N. meningitidis. We have developed an easy-to-use implementation of treeWAS in the R environment, which should be useful to a wide range of researchers in microbial genomics.
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14
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Capel E, Barnier JP, Zomer AL, Bole-Feysot C, Nussbaumer T, Jamet A, Lécuyer H, Euphrasie D, Virion Z, Frapy E, Pélissier P, Join-Lambert O, Rattei T, Bourdoulous S, Nassif X, Coureuil M. Peripheral blood vessels are a niche for blood-borne meningococci. Virulence 2017; 8:1808-1819. [PMID: 29099305 DOI: 10.1080/21505594.2017.1391446] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Neisseria meningitidis is the causative agent of cerebrospinal meningitis and that of a rapidly progressing fatal septic shock known as purpura fulminans. Meningococcemia is characterized by bacterial adhesion to human endothelial cells of the microvessels. Host specificity has hampered studies on the role of blood vessels colonization in N. meningitidis associated pathogenesis. In this work, using a humanized model of SCID mice allowing the study of bacterial adhesion to human cells in an in vivo context we demonstrate that meningococcal colonization of human blood vessels is a prerequisite to the establishment of sepsis and lethality. To identify the molecular pathways involved in bacterial virulence, we performed transposon insertion site sequencing (Tn-seq) in vivo. Our results demonstrate that 36% of the genes that are important for growth in the blood of mice are dispensable when bacteria colonize human blood vessels, suggesting that human endothelial cells lining the blood vessels are feeding niches for N. meningitidis in vivo. Altogether, our work proposes a new paradigm for meningococcal virulence in which colonization of blood vessels is associated with metabolic adaptation and sustained bacteremia responsible for sepsis and subsequent lethality.
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Affiliation(s)
- Elena Capel
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France
| | - Jean-Philippe Barnier
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France.,c Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades , Paris , France
| | - Aldert L Zomer
- d Department of Infectious Diseases and Immunology , Faculty of Veterinary Medicine, Utrecht University , Utrecht , The Netherlands
| | - Christine Bole-Feysot
- e Plateforme génomique de l'Institut Imagine, INSERM UMR 1163, Paris Descartes Sorbonne Université Paris Cité , Paris , France
| | - Thomas Nussbaumer
- f CUBE - Division of Computational Systems Biology, Dept. of Microbiology and Ecosystem Science , University of Vienna , Vienna , Austria
| | - Anne Jamet
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France.,c Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades , Paris , France
| | - Hervé Lécuyer
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France.,c Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades , Paris , France
| | - Daniel Euphrasie
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France
| | - Zoé Virion
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France
| | - Eric Frapy
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France
| | - Philippe Pélissier
- g Service de Chirurgie Plastique Reconstructrice et Esthétique, Groupe Hospitalier Paris Saint Joseph , Paris , France
| | - Olivier Join-Lambert
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France.,c Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades , Paris , France
| | - Thomas Rattei
- f CUBE - Division of Computational Systems Biology, Dept. of Microbiology and Ecosystem Science , University of Vienna , Vienna , Austria
| | - Sandrine Bourdoulous
- b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France.,h INSERM U1016, Institut Cochin , Paris , France.,i CNRS UMR8104 , Paris , France
| | - Xavier Nassif
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France.,c Assistance Publique - Hôpitaux de Paris, Hôpital Necker Enfants Malades , Paris , France
| | - Mathieu Coureuil
- a Institut Necker Enfants-Malades, INSERM U1151, Equipe 11 , Paris , France.,b Université Paris Descartes; Sorbonne Paris Cité, Faculté de Médecine , Paris , France
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15
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Peng C, Lin Y, Luo H, Gao F. A Comprehensive Overview of Online Resources to Identify and Predict Bacterial Essential Genes. Front Microbiol 2017; 8:2331. [PMID: 29230204 PMCID: PMC5711816 DOI: 10.3389/fmicb.2017.02331] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/13/2017] [Indexed: 12/15/2022] Open
Abstract
Genes critical for the survival or reproduction of an organism in certain circumstances are classified as essential genes. Essential genes play a significant role in deciphering the survival mechanism of life. They may be greatly applied to pharmaceutics and synthetic biology. The continuous progress of experimental method for essential gene identification has accelerated the accumulation of gene essentiality data which facilitates the study of essential genes in silico. In this article, we present some available online resources related to gene essentiality, including bioinformatic software tools for transposon sequencing (Tn-seq) analysis, essential gene databases and online services to predict bacterial essential genes. We review several computational approaches that have been used to predict essential genes, and summarize the features used for gene essentiality prediction. In addition, we evaluate the available online bacterial essential gene prediction servers based on the experimentally validated essential gene sets of 30 bacteria from DEG. This article is intended to be a quick reference guide for the microbiologists interested in the essential genes.
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Affiliation(s)
- Chong Peng
- Department of Physics, School of Science, Tianjin University, Tianjin, China
| | - Yan Lin
- Department of Physics, School of Science, Tianjin University, Tianjin, China
| | - Hao Luo
- Department of Physics, School of Science, Tianjin University, Tianjin, China
| | - Feng Gao
- Department of Physics, School of Science, Tianjin University, Tianjin, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
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16
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Bauer S, Helmreich J, Zachary M, Kaethner M, Heinrichs E, Rudel T, Beier D. The sibling sRNAs NgncR_162 and NgncR_163 of Neisseria gonorrhoeae participate in the expression control of metabolic, transport and regulatory proteins. MICROBIOLOGY-SGM 2017; 163:1720-1734. [PMID: 29058643 DOI: 10.1099/mic.0.000548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neisseria gonorrhoeae is the causative agent of gonorrhoea, the second most common bacterial sexually transmitted disease. Riboregulation mediated by small regulatory RNAs (sRNAs) is increasingly recognized as an important means of gene expression control in this human-restricted pathogen. sRNAs act at the post-transcriptional level by base-pairing with their target mRNAs which affects translation initiation and/or mRNA stability. In this study we initiated the characterization of a pair of highly conserved sRNAs of N. gonorrhoeae which exhibit redundant functions in the control of a common set of target genes. The identified targets of the sibling sRNAs NgncR_162 and NgncR_163 participate in basic metabolic processes including the methylcitrate and citrate cycle, aa uptake and degradation, and also in transcription regulation. Our data indicate that the sibling sRNAs control their targets via direct base-pairing between the same single-stranded domain(s) of the sRNA and the ribosome binding site in the 5'-untranslated region of the mRNA.
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Affiliation(s)
- Susanne Bauer
- Chair of Microbiology, University of Würzburg, Biocenter, Würzburg, Germany
| | - Jonas Helmreich
- Chair of Microbiology, University of Würzburg, Biocenter, Würzburg, Germany
| | - Marie Zachary
- Chair of Microbiology, University of Würzburg, Biocenter, Würzburg, Germany
| | - Marc Kaethner
- Chair of Microbiology, University of Würzburg, Biocenter, Würzburg, Germany
| | | | - Thomas Rudel
- Chair of Microbiology, University of Würzburg, Biocenter, Würzburg, Germany
| | - Dagmar Beier
- Chair of Microbiology, University of Würzburg, Biocenter, Würzburg, Germany
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17
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Heidrich N, Bauriedl S, Barquist L, Li L, Schoen C, Vogel J. The primary transcriptome of Neisseria meningitidis and its interaction with the RNA chaperone Hfq. Nucleic Acids Res 2017; 45:6147-6167. [PMID: 28334889 PMCID: PMC5449619 DOI: 10.1093/nar/gkx168] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/02/2017] [Indexed: 12/15/2022] Open
Abstract
Neisseria meningitidis is a human commensal that can also cause life-threatening meningitis and septicemia. Despite growing evidence for RNA-based regulation in meningococci, their transcriptome structure and output of regulatory small RNAs (sRNAs) are incompletely understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptome of N. meningitidis strain 8013. Annotation of 1625 transcriptional start sites defines transcription units for most protein-coding genes but also reveals a paucity of classical σ70-type promoters, suggesting the existence of activators that compensate for the lack of −35 consensus sequences in N. meningitidis. The transcriptome maps also reveal 65 candidate sRNAs, a third of which were validated by northern blot analysis. Immunoprecipitation with the RNA chaperone Hfq drafts an unexpectedly large post-transcriptional regulatory network in this organism, comprising 23 sRNAs and hundreds of potential mRNA targets. Based on this data, using a newly developed gfp reporter system we validate an Hfq-dependent mRNA repression of the putative colonization factor PrpB by the two trans-acting sRNAs RcoF1/2. Our genome-wide RNA compendium will allow for a better understanding of meningococcal transcriptome organization and riboregulation with implications for colonization of the human nasopharynx.
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Affiliation(s)
- Nadja Heidrich
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany
| | - Saskia Bauriedl
- Institute for Hygiene and Microbiology (IHM), University of Würzburg, D-97080 Würzburg, Germany
| | - Lars Barquist
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany
| | - Lei Li
- Division of Biostatistics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christoph Schoen
- Institute for Hygiene and Microbiology (IHM), University of Würzburg, D-97080 Würzburg, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany.,Helmholtz Institute for RNA-based Infection Research (HIRI), D-97080 Würzburg, Germany
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18
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Abstract
Neisseria meningitidis is a harmless commensal bacterium finely adapted to humans. Unfortunately, under “privileged” conditions, it adopts a “devious” lifestyle leading to uncontrolled behavior characterized by the unleashing of molecular weapons causing potentially lethal disease such as sepsis and acute meningitis. Indeed, despite the lack of a classic repertoire of virulence genes in
N. meningitidis separating commensal from invasive strains, molecular epidemiology and functional genomics studies suggest that carriage and invasive strains belong to genetically distinct populations characterized by an exclusive pathogenic potential. In the last few years, “omics” technologies have helped scientists to unwrap the framework drawn by
N. meningitidis during different stages of colonization and disease. However, this scenario is still incomplete and would benefit from the implementation of physiological tissue models for the reproduction of mucosal and systemic interactions
in vitro. These emerging technologies supported by recent advances in the world of stem cell biology hold the promise for a further understanding of
N. meningitidis pathogenesis.
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19
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Tanwer P, Bauer S, Heinrichs E, Panda G, Saluja D, Rudel T, Beier D. Post-transcriptional regulation of target genes by the sRNA FnrS in Neisseria gonorrhoeae. MICROBIOLOGY-SGM 2017; 163:1081-1092. [PMID: 28691898 DOI: 10.1099/mic.0.000484] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Small non-coding RNAs (sRNAs) are well-established post-transcriptional regulators of gene expression in bacteria that respond to a variety of environmental stimuli. They usually act by base-pairing with their target mRNAs, which is commonly facilitated by the RNA chaperone Hfq. In this study we initiated the analysis of the sRNA FnrS of Neisseria gonorrhoeae, which is induced under anaerobic conditions. We identified four putative FnrS target genes using bioinformatics approaches and validated these target genes using translational reporter gene fusions in both Escherichia coli and N. gonorrhoeae, thereby demonstrating their downregulation by direct base-pairing between the respective mRNA and FnrS. We demonstrate deregulation of target mRNAs upon deletion of fnrS and provide evidence that the isc gene cluster required for iron-sulfur cluster biosynthesis, which harbours iscS, which is a direct target of FnrS, is coordinately downregulated by the sRNA. By mutational analysis we show that, surprisingly, three distinct regions of FnrS are employed for interaction with different target genes.
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Affiliation(s)
- Pooja Tanwer
- Chair of Microbiology, University of Würzburg, Biocenter, Germany.,Dr B R Ambedkar Center for Biomedical Research, University of Delhi, India
| | - Susanne Bauer
- Chair of Microbiology, University of Würzburg, Biocenter, Germany
| | | | - Gurudutta Panda
- Institute of Network Biology (INET), Helmholtz Zentrum München, Germany
| | - Daman Saluja
- Dr B R Ambedkar Center for Biomedical Research, University of Delhi, India
| | - Thomas Rudel
- Chair of Microbiology, University of Würzburg, Biocenter, Germany
| | - Dagmar Beier
- Chair of Microbiology, University of Würzburg, Biocenter, Germany
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20
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Schubert-Unkmeir A. Molecular mechanisms involved in the interaction of Neisseria meningitidis with cells of the human blood-cerebrospinal fluid barrier. Pathog Dis 2017; 75:3061359. [PMID: 28334198 DOI: 10.1093/femspd/ftx023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/02/2017] [Indexed: 11/15/2022] Open
Abstract
Neisseria meningitidis is one of the most common aetiological agents of bacterial meningitis, affecting predominantly children and young adults. The interaction of N. meningitidis with human endothelial cells lining blood vessels of the blood-cerebrospinal fluid barrier (B-CSFB) is critical for meningitis development. In recent decades, there has been a significant increase in understanding of the molecular mechanisms involved in the interaction of N. meningitidis with brain vascular cells. In this review, we will describe how N. meningitidis adheres to the brain vasculature, may enter inside these cells, hijack receptor signalling pathways and alter host-cell responses in order to traverse the B-CSFB.
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21
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Host cell-derived lactate functions as an effector molecule in Neisseria meningitidis microcolony dispersal. PLoS Pathog 2017; 13:e1006251. [PMID: 28384279 PMCID: PMC5383330 DOI: 10.1371/journal.ppat.1006251] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/18/2017] [Indexed: 12/11/2022] Open
Abstract
The development of meningococcal disease, caused by the human pathogen Neisseria meningitidis, is preceded by the colonization of the epithelial layer in the nasopharynx. After initial adhesion to host cells meningococci form aggregates, through pilus-pilus interactions, termed microcolonies from which the bacteria later detach. Dispersal from microcolonies enables access to new colonization sites and facilitates the crossing of the cell barrier; however, this process is poorly understood. In this study, we used live-cell imaging to investigate the process of N. meningitidis microcolony dispersal. We show that direct contact with host cells is not required for microcolony dispersal, instead accumulation of a host-derived effector molecule induces microcolony dispersal. By using a host-cell free approach, we demonstrated that lactate, secreted from host cells, initiate rapid dispersal of microcolonies. Interestingly, metabolic utilization of lactate by the bacteria was not required for induction of dispersal, suggesting that lactate plays a role as a signaling molecule. Furthermore, Neisseria gonorrhoeae microcolony dispersal could also be induced by lactate. These findings reveal a role of host-secreted lactate in microcolony dispersal and virulence of pathogenic Neisseria. The human restricted pathogen Neisseria meningitidis is a major cause of bacterial meningitis and sepsis worldwide. Colonization of the mucosal layer in the upper respiratory tract is essential to establish invasive disease. The initial interaction with host cells is characterized by bacterial proliferation and adhesion as aggregates, called microcolonies. Detachment from microcolonies in the nasopharyngeal epithelium facilitates crossing of the cell barrier that can result in invasive disease, yet this process is poorly understood. Here we demonstrate that lactate, an abundant molecule in host mucosal environments, induces N. meningitidis microcolony dispersal. Interestingly, metabolic utilization of lactate by the bacteria was not required for the process, suggesting that lactate play a role as a signaling molecule in pathogenic Neisseria. We propose that the microcolony dispersal in pathogenic Neisseria is influenced by environmental concentrations of lactate. These findings will assist in better understanding the transition from asymptomatic carriage to invasive disease.
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22
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Perry BJ, Akter MS, Yost CK. The Use of Transposon Insertion Sequencing to Interrogate the Core Functional Genome of the Legume Symbiont Rhizobium leguminosarum. Front Microbiol 2016; 7:1873. [PMID: 27920770 PMCID: PMC5118466 DOI: 10.3389/fmicb.2016.01873] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 11/07/2016] [Indexed: 02/04/2023] Open
Abstract
The free-living legume symbiont Rhizobium leguminosarum is of significant economic value because of its ability to provide fixed nitrogen to globally important leguminous food crops, such as peas and lentils. Discovery based research into the genetics and physiology of R. leguminosarum provides the foundational knowledge necessary for understanding the bacterium's complex lifestyle, necessary for augmenting its use in an agricultural setting. Transposon insertion sequencing (INSeq) facilitates high-throughput forward genetic screening at a genomic scale to identify individual genes required for growth in a specific environment. In this study we applied INSeq to screen the genome of R. leguminosarum bv. viciae strain 3841 (RLV3841) for genes required for growth on minimal mannitol containing medium. Results from this study were contrasted with a prior INSeq experiment screened on peptide rich media to identify a common set of functional genes necessary for basic physiology. Contrasting the two growth conditions indicated that approximately 10% of the chromosome was required for growth, under both growth conditions. Specific genes that were essential to singular growth conditions were also identified. Data from INSeq screening on mannitol as a sole carbon source were used to reconstruct a metabolic map summarizing growth impaired phenotypes observed in the Embden-Meyerhof-Parnas pathway, Entner-Doudoroff pathway, pentose phosphate pathway, and tricarboxylic acid cycle. This revealed the presence of mannitol dependent and independent metabolic pathways required for growth, along with identifying metabolic steps with isozymes or possible carbon flux by-passes. Additionally, genes were identified on plasmids pRL11 and pRL12 that are likely to encode functional activities important to the central physiology of RLV3841.
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Affiliation(s)
| | - Mir S Akter
- Department of Biology, University of Regina Regina, SK, Canada
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