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Espaillat A, Alvarez L, Torrens G, Ter Beek J, Miguel-Ruano V, Irazoki O, Gago F, Hermoso JA, Berntsson RPA, Cava F. A distinctive family of L,D-transpeptidases catalyzing L-Ala-mDAP crosslinks in Alpha- and Betaproteobacteria. Nat Commun 2024; 15:1343. [PMID: 38351082 PMCID: PMC10864386 DOI: 10.1038/s41467-024-45620-5] [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: 11/09/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024] Open
Abstract
The bacterial cell-wall peptidoglycan is made of glycan strands crosslinked by short peptide stems. Crosslinks are catalyzed by DD-transpeptidases (4,3-crosslinks) and LD-transpeptidases (3,3-crosslinks). However, recent research on non-model species has revealed novel crosslink types, suggesting the existence of uncharacterized enzymes. Here, we identify an LD-transpeptidase, LDTGo, that generates 1,3-crosslinks in the acetic-acid bacterium Gluconobacter oxydans. LDTGo-like proteins are found in Alpha- and Betaproteobacteria lacking LD3,3-transpeptidases. In contrast with the strict specificity of typical LD- and DD-transpeptidases, LDTGo can use non-terminal amino acid moieties for crosslinking. A high-resolution crystal structure of LDTGo reveals unique features when compared to LD3,3-transpeptidases, including a proline-rich region that appears to limit substrate access, and a cavity accommodating both glycan chain and peptide stem from donor muropeptides. Finally, we show that DD-crosslink turnover is involved in supplying the necessary substrate for LD1,3-transpeptidation. This phenomenon underscores the interplay between distinct crosslinking mechanisms in maintaining cell wall integrity in G. oxydans.
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Affiliation(s)
- Akbar Espaillat
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
- Chr. Hansen A/S, Microbial Physiology, R&D, 2970, Hoersholm, Denmark
| | - Laura Alvarez
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Gabriel Torrens
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Josy Ter Beek
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Vega Miguel-Ruano
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Blas Cabrera", CSIC, Madrid, Spain
| | - Oihane Irazoki
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden
| | - Federico Gago
- Department of Biomedical Sciences & IQM-CSIC Associate Unit, School of Medicine and Health Sciences, University of Alcalá, E-28805, Madrid, Alcalá de Henares, Spain
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Blas Cabrera", CSIC, Madrid, Spain
| | - Ronnie P-A Berntsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, SciLifeLab, Umeå University, Umeå, Sweden.
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2
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Xuan M, Gu X, Liu Y, Yang L, Li Y, Huang D, Li J, Xue C. Intratumoral microorganisms in tumors of the digestive system. Cell Commun Signal 2024; 22:69. [PMID: 38273292 PMCID: PMC10811838 DOI: 10.1186/s12964-023-01425-5] [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: 11/07/2023] [Accepted: 12/06/2023] [Indexed: 01/27/2024] Open
Abstract
Tumors of the digestive system pose a significant threat to human health and longevity. These tumors are associated with high morbidity and mortality rates, leading to a heavy economic burden on healthcare systems. Several intratumoral microorganisms are present in digestive system tumors, and their sources and abundance display significant heterogeneity depending on the specific tumor subtype. These microbes have a complex and precise function in the neoplasm. They can facilitate tumor growth through various mechanisms, such as inducing DNA damage, influencing the antitumor immune response, and promoting the degradation of chemotherapy drugs. Therefore, these microorganisms can be targeted to inhibit tumor progression for improving overall patient prognosis. This review focuses on the current research progress on microorganisms present in the digestive system tumors and how they influence the initiation, progression, and prognosis of tumors. Furthermore, the primary sources and constituents of tumor microbiome are delineated. Finally, we summarize the application potential of intratumoral microbes in the diagnosis, treatment, and prognosis prediction of digestive system tumors. Video Abstract.
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Affiliation(s)
- Mengjuan Xuan
- Department of Infectious Disease, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe East Road, Erqi District, Zhengzhou, 450052, China
| | - Xinyu Gu
- Department of Oncology, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, 471000, Henan, China
| | - Yingru Liu
- Department of Infectious Disease, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe East Road, Erqi District, Zhengzhou, 450052, China
| | - Li Yang
- Department of Infectious Disease, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe East Road, Erqi District, Zhengzhou, 450052, China
| | - Yi Li
- Department of Infectious Disease, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe East Road, Erqi District, Zhengzhou, 450052, China
| | - Di Huang
- Department of Child Health Care, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, Henan, China
| | - Juan Li
- Department of Infectious Disease, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe East Road, Erqi District, Zhengzhou, 450052, China.
| | - Chen Xue
- Department of Infectious Disease, The First Affiliated Hospital of Zhengzhou University, No. 1 Jianshe East Road, Erqi District, Zhengzhou, 450052, China.
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3
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Zeden MS, Gallagher LA, Bueno E, Nolan AC, Ahn J, Shinde D, Razvi F, Sladek M, Burke Ó, O’Neill E, Fey PD, Cava F, Thomas VC, O’Gara JP. Metabolic reprogramming and altered cell envelope characteristics in a pentose phosphate pathway mutant increases MRSA resistance to β-lactam antibiotics. PLoS Pathog 2023; 19:e1011536. [PMID: 37486930 PMCID: PMC10399904 DOI: 10.1371/journal.ppat.1011536] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/03/2023] [Accepted: 07/04/2023] [Indexed: 07/26/2023] Open
Abstract
Central metabolic pathways control virulence and antibiotic resistance, and constitute potential targets for antibacterial drugs. In Staphylococcus aureus the role of the pentose phosphate pathway (PPP) remains largely unexplored. Mutation of the 6-phosphogluconolactonase gene pgl, which encodes the only non-essential enzyme in the oxidative phase of the PPP, significantly increased MRSA resistance to β-lactam antibiotics, particularly in chemically defined media with physiologically-relevant concentrations of glucose, and reduced oxacillin (OX)-induced lysis. Expression of the methicillin-resistance penicillin binding protein 2a and peptidoglycan architecture were unaffected. Carbon tracing and metabolomics revealed extensive metabolic reprogramming in the pgl mutant including increased flux to glycolysis, the TCA cycle, and several cell envelope precursors, which was consistent with increased β-lactam resistance. Morphologically, pgl mutant cells were smaller than wild-type with a thicker cell wall and ruffled surface when grown in OX. The pgl mutation reduced resistance to Congo Red, sulfamethoxazole and oxidative stress, and increased resistance to targocil, fosfomycin and vancomycin. Levels of lipoteichoic acids (LTAs) were significantly reduced in pgl, which may limit cell lysis, while the surface charge of pgl cells was significantly more positive. A vraG mutation in pgl reversed the increased OX resistance phenotype, and partially restored wild-type surface charge, but not LTA levels. Mutations in vraF or graRS from the VraFG/GraRS complex that regulates DltABCD-mediated d-alanylation of teichoic acids (which in turn controls β-lactam resistance and surface charge), also restored wild-type OX susceptibility. Collectively these data show that reduced levels of LTAs and OX-induced lysis combined with a VraFG/GraRS-dependent increase in cell surface positive charge are accompanied by significantly increased OX resistance in an MRSA pgl mutant.
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Affiliation(s)
- Merve S. Zeden
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Laura A. Gallagher
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Emilio Bueno
- Department of Molecular Biology, Umeå University, MIMS—Laboratory for Molecular Infection Medicine Sweden, Umeå, Sweden
| | - Aaron C. Nolan
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Jongsam Ahn
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Dhananjay Shinde
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Fareha Razvi
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Margaret Sladek
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Órla Burke
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Eoghan O’Neill
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Felipe Cava
- Department of Molecular Biology, Umeå University, MIMS—Laboratory for Molecular Infection Medicine Sweden, Umeå, Sweden
| | - Vinai C. Thomas
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - James P. O’Gara
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
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4
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Trotta KL, Hayes BM, Schneider JP, Wang J, Todor H, Rockefeller Grimes P, Zhao Z, Hatleberg WL, Silvis MR, Kim R, Koo BM, Basler M, Chou S. Lipopolysaccharide transport regulates bacterial sensitivity to a cell wall-degrading intermicrobial toxin. PLoS Pathog 2023; 19:e1011454. [PMID: 37363922 PMCID: PMC10328246 DOI: 10.1371/journal.ppat.1011454] [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: 05/02/2023] [Revised: 07/07/2023] [Accepted: 06/01/2023] [Indexed: 06/28/2023] Open
Abstract
Gram-negative bacteria can antagonize neighboring microbes using a type VI secretion system (T6SS) to deliver toxins that target different essential cellular features. Despite the conserved nature of these targets, T6SS potency can vary across recipient species. To understand the functional basis of intrinsic T6SS susceptibility, we screened for essential Escherichia coli (Eco) genes that affect its survival when antagonized by a cell wall-degrading T6SS toxin from Pseudomonas aeruginosa, Tae1. We revealed genes associated with both the cell wall and a separate layer of the cell envelope, lipopolysaccharide, that modulate Tae1 toxicity in vivo. Disruption of genes in early lipopolysaccharide biosynthesis provided Eco with novel resistance to Tae1, despite significant cell wall degradation. These data suggest that Tae1 toxicity is determined not only by direct substrate damage, but also by indirect cell envelope homeostasis activities. We also found that Tae1-resistant Eco exhibited reduced cell wall synthesis and overall slowed growth, suggesting that reactive cell envelope maintenance pathways could promote, not prevent, self-lysis. Together, our study reveals the complex functional underpinnings of susceptibility to Tae1 and T6SS which regulate the impact of toxin-substrate interactions in vivo.
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Affiliation(s)
- Kristine L. Trotta
- Department of Biochemistry & Biophysics, University of California–San Francisco, San Francisco, California, United States of America
| | - Beth M. Hayes
- Department of Biochemistry & Biophysics, University of California–San Francisco, San Francisco, California, United States of America
| | | | - Jing Wang
- Biozentrum, University of Basel, Basel, Switzerland
| | - Horia Todor
- Department of Cell and Tissue Biology, University of California–San Francisco, San Francisco, California, United States of America
| | - Patrick Rockefeller Grimes
- Department of Biochemistry & Biophysics, University of California–San Francisco, San Francisco, California, United States of America
| | - Ziyi Zhao
- Department of Biochemistry & Biophysics, University of California–San Francisco, San Francisco, California, United States of America
| | | | - Melanie R. Silvis
- Department of Cell and Tissue Biology, University of California–San Francisco, San Francisco, California, United States of America
| | - Rachel Kim
- Department of Biochemistry & Biophysics, University of California–San Francisco, San Francisco, California, United States of America
| | - Byoung Mo Koo
- Department of Cell and Tissue Biology, University of California–San Francisco, San Francisco, California, United States of America
| | - Marek Basler
- Biozentrum, University of Basel, Basel, Switzerland
| | - Seemay Chou
- Department of Biochemistry & Biophysics, University of California–San Francisco, San Francisco, California, United States of America
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5
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Figueroa-Cuilan WM, Irazoki O, Feeley M, Smith E, Nguyen T, Cava F, Goley ED. Quantitative analysis of morphogenesis and growth dynamics in an obligate intracellular bacterium. Mol Biol Cell 2023; 34:ar69. [PMID: 37017481 PMCID: PMC10295487 DOI: 10.1091/mbc.e23-01-0023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/06/2023] Open
Abstract
Obligate intracellular bacteria of the order Rickettsiales include important human pathogens. However, our understanding of the biology of Rickettsia species is limited by challenges imposed by their obligate intracellular lifestyle. To overcome this roadblock, we developed methods to assess cell wall composition, growth, and morphology of Rickettsia parkeri, a human pathogen in the spotted fever group of the Rickettsia genus. Analysis of the cell wall of R. parkeri revealed unique features that distinguish it from free-living alphaproteobacteria. Using a novel fluorescence microscopy approach, we quantified R. parkeri morphology in live host cells and found that the fraction of the population undergoing cell division decreased over the course of infection. We further demonstrated the feasibility of localizing fluorescence fusions, for example, to the cell division protein ZapA, in live R. parkeri for the first time. To evaluate population growth kinetics, we developed an imaging-based assay that improves on the throughput and resolution of other methods. Finally, we applied these tools to quantitatively demonstrate that the actin homologue MreB is required for R. parkeri growth and rod shape. Collectively, a toolkit was developed of high-throughput, quantitative tools to understand growth and morphogenesis of R. parkeri that is translatable to other obligate intracellular bacteria.
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Affiliation(s)
- Wanda M. Figueroa-Cuilan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Marissa Feeley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Erika Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Trung Nguyen
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
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6
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Trotta KL, Hayes BM, Schneider JP, Wang J, Todor H, Grimes PR, Zhao Z, Hatleberg WL, Silvis MR, Kim R, Koo BM, Basler M, Chou S. Lipopolysaccharide integrity primes bacterial sensitivity to a cell wall-degrading intermicrobial toxin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524922. [PMID: 36747731 PMCID: PMC9900751 DOI: 10.1101/2023.01.20.524922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Gram-negative bacteria can antagonize neighboring microbes using a type VI secretion system (T6SS) to deliver toxins that target different essential cellular features. Despite the conserved nature of these targets, T6SS potency can vary across recipient species. To understand the molecular basis of intrinsic T6SS susceptibility, we screened for essential Escherichia coli genes that affect its survival when antagonized by a cell wall-degrading T6SS toxin from Pseudomonas aeruginosa , Tae1. We revealed genes associated with both the cell wall and a separate layer of the cell envelope, surface lipopolysaccharide, that modulate Tae1 toxicity in vivo . Disruption of lipopolysaccharide synthesis provided Escherichia coli (Eco) with novel resistance to Tae1, despite significant cell wall degradation. These data suggest that Tae1 toxicity is determined not only by direct substrate damage, but also by indirect cell envelope homeostasis activities. We also found that Tae1-resistant Eco exhibited reduced cell wall synthesis and overall slowed growth, suggesting that reactive cell envelope maintenance pathways could promote, not prevent, self-lysis. Together, our study highlights the consequences of co-regulating essential pathways on recipient fitness during interbacterial competition, and how antibacterial toxins leverage cellular vulnerabilities that are both direct and indirect to their specific targets in vivo .
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Affiliation(s)
- Kristine L Trotta
- Department of Biochemistry & Biophysics, University of California – San Francisco, San Francisco, CA, USA
| | - Beth M Hayes
- Department of Biochemistry & Biophysics, University of California – San Francisco, San Francisco, CA, USA
| | - Johannes P Schneider
- Focal Area Infection Biology, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH - 4056 Basel, Switzerland
| | - Jing Wang
- Focal Area Infection Biology, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH - 4056 Basel, Switzerland
| | - Horia Todor
- Department of Cell and Tissue Biology, University of California – San Francisco, San Francisco, CA, USA
| | - Patrick Rockefeller Grimes
- Department of Biochemistry & Biophysics, University of California – San Francisco, San Francisco, CA, USA
| | - Ziyi Zhao
- Department of Biochemistry & Biophysics, University of California – San Francisco, San Francisco, CA, USA
| | | | - Melanie R Silvis
- Department of Cell and Tissue Biology, University of California – San Francisco, San Francisco, CA, USA
| | - Rachel Kim
- Department of Biochemistry & Biophysics, University of California – San Francisco, San Francisco, CA, USA
| | - Byoung Mo Koo
- Department of Cell and Tissue Biology, University of California – San Francisco, San Francisco, CA, USA
| | - Marek Basler
- Focal Area Infection Biology, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH - 4056 Basel, Switzerland
| | - Seemay Chou
- Department of Biochemistry & Biophysics, University of California – San Francisco, San Francisco, CA, USA
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7
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Deletion of pbpC Enhances Bacterial Pathogenicity on Tomato by Affecting Biofilm Formation, Exopolysaccharides Production, and Exoenzyme Activities in Clavibacter michiganensis. Int J Mol Sci 2023; 24:ijms24065324. [PMID: 36982399 PMCID: PMC10049144 DOI: 10.3390/ijms24065324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 02/14/2023] [Accepted: 03/07/2023] [Indexed: 03/18/2023] Open
Abstract
Penicillin-binding proteins (PBPs) are considered essential for bacterial peptidoglycan biosynthesis and cell wall assembly. Clavibacter michiganensis is a representative Gram-positive bacterial species that causes bacterial canker in tomato. pbpC plays a significant role in maintaining cell morphological characteristics and stress responses in C. michiganensis. The current study demonstrated that the deletion of pbpC commonly enhances bacterial pathogenicity in C. michiganensis and revealed the mechanisms through which this occurs. The expression of interrelated virulence genes, including celA, xysA, xysB, and pelA, were significantly upregulated in △pbpC mutants. Compared with those in wild-type strains, exoenzyme activities, the formation of biofilm, and the production of exopolysaccharides (EPS) were significantly increased in △pbpC mutants. It is noteworthy that EPS were responsible for the enhancement in bacterial pathogenicity, with the degree of necrotic tomato stem cankers intensifying with the injection of a gradient of EPS from C. michiganensis. These findings highlight new insights into the role of pbpC affecting bacterial pathogenicity, with an emphasis on EPS, advancing the current understanding of phytopathogenic infection strategies for Gram-positive bacteria.
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8
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Zeden MS, Gallagher LA, Bueno E, Nolan AC, Ahn J, Shinde D, Razvi F, Sladek M, Burke Ó, O'Neill E, Fey PD, Cava F, Thomas VC, O'Gara JP. Metabolic reprogramming and flux to cell envelope precursors in a pentose phosphate pathway mutant increases MRSA resistance to β-lactam antibiotics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.03.530734. [PMID: 36945400 PMCID: PMC10028837 DOI: 10.1101/2023.03.03.530734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Central metabolic pathways controls virulence and antibiotic resistance, and constitute potential targets for antibacterial drugs. In Staphylococcus aureus the role of the pentose phosphate pathway (PPP) remains largely unexplored. Mutation of the 6-phosphogluconolactonase gene pgl, which encodes the only non-essential enzyme in the oxidative phase of the PPP, significantly increased MRSA resistance to β-lactam antibiotics, particularly in chemically defined media with glucose, and reduced oxacillin (OX)-induced lysis. Expression of the methicillin-resistance penicillin binding protein 2a and peptidoglycan architecture were unaffected. Carbon tracing and metabolomics revealed extensive metabolic reprogramming in the pgl mutant including increased flux to glycolysis, the TCA cycle, and several cell envelope precursors, which was consistent with increased β-lactam resistance. Morphologically, pgl mutant cells were smaller than wild-type with a thicker cell wall and ruffled surface when grown in OX. Further evidence of the pleiotropic effect of the pgl mutation was reduced resistance to Congo Red, sulfamethoxazole and oxidative stress, and increased resistance to targocil, fosfomycin and vancomycin. Reduced binding of wheat germ agglutinin (WGA) to pgl was indicative of lower wall teichoic acid/lipoteichoic acid levels or altered teichoic acid structures. Mutations in the vraFG or graRS loci reversed the increased OX resistance phenotype and restored WGA binding to wild-type levels. VraFG/GraRS was previously implicated in susceptibility to cationic antimicrobial peptides and vancomycin, and these data reveal a broader role for this multienzyme membrane complex in the export of cell envelope precursors or modifying subunits required for resistance to diverse antimicrobial agents. Altogether our study highlights important roles for the PPP and VraFG/GraRS in β-lactam resistance, which will support efforts to identify new drug targets and reintroduce β-lactams in combination with adjuvants or other antibiotics for infections caused by MRSA and other β-lactam resistant pathogens. Author summary High-level resistance to penicillin-type (β-lactam) antibiotics significantly limits the therapeutic options for patients with MRSA infections necessitating the use of newer agents, for which reduced susceptibility has already been described. Here we report for the first time that the central metabolism pentose phosphate pathway controls MRSA resistance to penicillin-type antibiotics. We comprehensively demonstrated that mutation of the PPP gene pgl perturbed metabolism in MRSA leading to increased flux to cell envelope precursors to drive increased antibiotic resistance. Moreover, increased resistance was dependent on the VraRG/GraRS multienzyme membrane complex previously implicated in resistance to antimicrobial peptides and vancomycin. Our data thus provide new insights on MRSA mechanisms of β-lactam resistance, which will support efforts to expand the treatment options for infections caused by this and other antimicrobial resistant pathogens.
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9
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Dixon B, Sui C, Briley A, Hsu PC, Howell C. Continuous, Nondestructive Detection of Microorganism Growth at Buried Interfaces with Vascularized Polymers. ACS APPLIED BIO MATERIALS 2023; 6:519-528. [PMID: 36633595 DOI: 10.1021/acsabm.2c00837] [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: 01/13/2023]
Abstract
Evaluating surface bacterial growth at buried interfaces can be problematic due to the difficulties associated with obtaining samples. In this work, we present a new method to detect signals from microorganisms at buried interfaces that is nondestructive and can be conducted continuously. Inspired by vascular systems in nature that permit chemical communication between the surface and underlying tissues of an organism, we created a system in which an inert carrier fluid could be introduced into an empty vascular network embedded in a polymer matrix. When a microorganism layer was grown on top, small molecules produced by the growth process would diffuse down into the carrier fluid, which could then be collected and analyzed. We used this system to nondestructively detect signals from a surface layer of Escherichia coli using conductivity, ultraviolet-visible (UV-vis) absorbance spectroscopy, and high-performance liquid chromatography (HPLC) for organic acids, methods that ranged in sensitivity, time-to-result, and cost. Carrier fluid from sample vascularized polymers with surface bacterial growth recorded significantly higher values in both conductivity and absorbance at 350 nm compared to controls with no bacteria after 24 h. HPLC analysis showed three clear peaks that varied between the samples with bacteria and the controls without. Tests tracking the change in signals over 48 h showed clear trends that matched the bacterial growth curves, demonstrating the system's ability to monitor changes over time. A 2D finite element model of the system closely matched the experimental results, confirming the predictability of the system. Finally, tests using clinically relevant Staphylococcus aureus and Pseudomonas aeruginosa yielded differences in conductivity, absorbance, and HPLC peak areas unique to each species. This work lays the foundation for the use of vascularized polymers as an adaptive system for the continuous, nondestructive detection of surface microorganisms at buried interfaces in both industry and medicine.
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Affiliation(s)
- Brandon Dixon
- Department of Chemical and Biomedical Engineering, University of Maine, Orono, Maine04469, United States
| | - Chenxi Sui
- Thomas Lord Department of Mechanical Engineering and Material Science, Duke University, Durham, North Carolina27708, United States
| | - Anna Briley
- Department of Chemical and Biomedical Engineering, University of Maine, Orono, Maine04469, United States
| | - Po-Chun Hsu
- Thomas Lord Department of Mechanical Engineering and Material Science, Duke University, Durham, North Carolina27708, United States.,Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois60637, United States
| | - Caitlin Howell
- Department of Chemical and Biomedical Engineering, University of Maine, Orono, Maine04469, United States.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine04469, United States
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Daitch AK, Orsburn BC, Chen Z, Alvarez L, Eberhard CD, Sundararajan K, Zeinert R, Kreitler DF, Jakoncic J, Chien P, Cava F, Gabelli SB, Goley ED. EstG is a novel esterase required for cell envelope integrity in Caulobacter. Curr Biol 2023; 33:228-240.e7. [PMID: 36516849 PMCID: PMC9877181 DOI: 10.1016/j.cub.2022.11.037] [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: 05/13/2022] [Revised: 10/17/2022] [Accepted: 11/17/2022] [Indexed: 12/15/2022]
Abstract
Proper regulation of the bacterial cell envelope is critical for cell survival. Identification and characterization of enzymes that maintain cell envelope homeostasis is crucial, as they can be targets for effective antibiotics. In this study, we have identified a novel enzyme, called EstG, whose activity protects cells from a variety of lethal assaults in the ⍺-proteobacterium Caulobacter crescentus. Despite homology to transpeptidase family cell wall enzymes and an ability to protect against cell-wall-targeting antibiotics, EstG does not demonstrate biochemical activity toward cell wall substrates. Instead, EstG is genetically connected to the periplasmic enzymes OpgH and BglX, responsible for synthesis and hydrolysis of osmoregulated periplasmic glucans (OPGs), respectively. The crystal structure of EstG revealed similarities to esterases and transesterases, and we demonstrated esterase activity of EstG in vitro. Using biochemical fractionation, we identified a cyclic hexamer of glucose as a likely substrate of EstG. This molecule is the first OPG described in Caulobacter and establishes a novel class of OPGs, the regulation and modification of which are important for stress survival and adaptation to fluctuating environments. Our data indicate that EstG, BglX, and OpgH comprise a previously unknown OPG pathway in Caulobacter. Ultimately, we propose that EstG is a novel enzyme that instead of acting on the cell wall, acts on cyclic OPGs to provide resistance to a variety of cellular stresses.
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Affiliation(s)
- Allison K Daitch
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA
| | - Benjamin C Orsburn
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA
| | - Zan Chen
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA
| | - Laura Alvarez
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden
| | - Colten D Eberhard
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA
| | - Kousik Sundararajan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA
| | - Rilee Zeinert
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, 240 Thatcher Road, Amherst, MA 01003, USA
| | - Dale F Kreitler
- National Synchrotron Light Source II, Bldg 745, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000, USA
| | - Jean Jakoncic
- National Synchrotron Light Source II, Bldg 745, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000, USA
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, 240 Thatcher Road, Amherst, MA 01003, USA
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden
| | - Sandra B Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA; Department of Medicine, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA
| | - Erin D Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD 21205, USA.
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11
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Xue C, Chu Q, Zheng Q, Yuan X, Su Y, Bao Z, Lu J, Li L. Current understanding of the intratumoral microbiome in various tumors. Cell Rep Med 2023; 4:100884. [PMID: 36652905 PMCID: PMC9873978 DOI: 10.1016/j.xcrm.2022.100884] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 09/18/2022] [Accepted: 12/13/2022] [Indexed: 01/19/2023]
Abstract
It is estimated that in the future, the number of new cancer cases worldwide will exceed the 19.3 million recorded in 2020, and the number of deaths will exceed 10 million. Cancer remains the leading cause of human mortality and lagging socioeconomic development. Intratumoral microbes have been revealed to exist in many cancer types, including pancreatic, colorectal, liver, esophageal, breast, and lung cancers. Intratumoral microorganisms affect not only the host immune system, but also the effectiveness of tumor chemotherapy. This review concentrates on the characteristics and roles of intratumoral microbes in various tumors. In addition, the potential of therapies targeting intratumoral microbes, as well as the main challenges currently delaying these therapies, are explored. Furthermore, we briefly summarize existing technical methods used to characterize intratumoral microbes. We hope to provide ideas for exploring intratumoral microbes as potential biomarkers and targets for tumor diagnosis, treatment, and prognostication.
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Affiliation(s)
- Chen Xue
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Qingfei Chu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Qiuxian Zheng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Xin Yuan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Yuanshuai Su
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Zhengyi Bao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Juan Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China.
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China.
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12
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Affiliation(s)
- Sven Truckenbrodt
- Convergent Research, E11 Bio. 1600 Harbor Bay Parkway, Alameda, California94502, United States
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13
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Mena-Bueno S, Poveda-Urkixo I, Irazoki O, Palacios L, Cava F, Zabalza-Baranguá A, Grilló MJ. Brucella melitensis Wzm/Wzt System: Changes in the Bacterial Envelope Lead to Improved Rev1Δwzm Vaccine Properties. Front Microbiol 2022; 13:908495. [PMID: 35875565 PMCID: PMC9306315 DOI: 10.3389/fmicb.2022.908495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
The lipopolysaccharide (LPS) O-polysaccharide (O-PS) is the main virulence factor in Brucella. After synthesis in the cytoplasmic membrane, O-PS is exported to the periplasm by the Wzm/Wzt system, where it is assembled into a LPS. This translocation also engages a bactoprenol carrier required for further biosynthesis pathways, such as cell wall biogenesis. Targeting O-PS export by blockage holds great potential for vaccine development, but little is known about the biological implications of each Wzm/Wzt moiety. To improve this knowledge and to elucidate its potential application as a vaccine, we constructed and studied wzm/wzt single- and double-deletion mutants, using the attenuated strain Brucella melitensis Rev1 as the parental strain. This allowed us to describe the composition of Brucella peptidoglycan for the first time. We observed that these mutants lack external O-PS yet trigger changes in genetic transcription and in phenotypic properties associated with the outer membrane and cell wall. The three mutants are highly attenuated; unexpectedly, Rev1Δwzm also excels as an immunogenic and effective vaccine against B. melitensis and Brucella ovis in mice, revealing that low persistence is not at odds with efficacy. Rev1Δwzm is attenuated in BeWo trophoblasts, does not infect mouse placentas, and is safe in pregnant ewes. Overall, these attributes and the minimal serological interference induced in sheep make Rev1Δwzm a highly promising vaccine candidate.
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Affiliation(s)
- Sara Mena-Bueno
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- Agronomy, Biotecnology and Food Department, Universidad Pública de Navarra (UPNA), Pamplona, Spain
| | - Irati Poveda-Urkixo
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Leyre Palacios
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Ana Zabalza-Baranguá
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - María Jesús Grilló
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- *Correspondence: María Jesús Grilló,
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14
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Abstract
While many mechanisms governing bacterial envelope homeostasis have been identified, others remain poorly understood. To decipher these processes, we previously developed an assay in the Gram-negative model Escherichia coli to identify genes involved in maintenance of envelope integrity. One such gene was ElyC, which was shown to be required for envelope integrity and peptidoglycan synthesis at room temperature. ElyC is predicted to be an integral inner membrane protein with a highly conserved domain of unknown function (DUF218). In this study, and stemming from a further characterization of the role of ElyC in maintaining cell envelope integrity, we serendipitously discovered an unappreciated form of oxidative stress in the bacterial envelope. We found that cells lacking ElyC overproduce hydroxyl radicals (HO•) in their envelope compartment and that HO• overproduction is directly or indirectly responsible for the peptidoglycan synthesis arrest, cell envelope integrity defects, and cell lysis of the ΔelyC mutant. Consistent with these observations, we show that the ΔelyC mutant defect is suppressed during anaerobiosis. HO• is known to cause DNA damage but to our knowledge has not been shown to interfere with peptidoglycan synthesis. Thus, our work implicates oxidative stress as an important stressor in the bacterial cell envelope and opens the door to future studies deciphering the mechanisms that render peptidoglycan synthesis sensitive to oxidative stress. IMPORTANCE Oxidative stress is caused by the production and excessive accumulation of oxygen reactive species. In bacterial cells, oxidative stress mediated by hydroxyl radicals is typically associated with DNA damage in the cytoplasm. Here, we reveal the existence of a pathway for oxidative stress in the envelope of Gram-negative bacteria. Stemming from the characterization of a poorly characterized gene, we found that HO• overproduction specifically in the envelope compartment causes inhibition of peptidoglycan synthesis and eventually bacterial cell lysis.
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15
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Weaver AI, Alvarez L, Rosch KM, Ahmed A, Wang GS, van Nieuwenhze MS, Cava F, Dörr T. Lytic transglycosylases mitigate periplasmic crowding by degrading soluble cell wall turnover products. eLife 2022; 11:e73178. [PMID: 35073258 PMCID: PMC8820737 DOI: 10.7554/elife.73178] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 01/23/2022] [Indexed: 11/25/2022] Open
Abstract
The peptidoglycan cell wall is a predominant structure of bacteria, determining cell shape and supporting survival in diverse conditions. Peptidoglycan is dynamic and requires regulated synthesis of new material, remodeling, and turnover - or autolysis - of old material. Despite exploitation of peptidoglycan synthesis as an antibiotic target, we lack a fundamental understanding of how peptidoglycan synthesis and autolysis intersect to maintain the cell wall. Here, we uncover a critical physiological role for a widely misunderstood class of autolytic enzymes, lytic transglycosylases (LTGs). We demonstrate that LTG activity is essential to survival by contributing to periplasmic processes upstream and independent of peptidoglycan recycling. Defects accumulate in Vibrio cholerae LTG mutants due to generally inadequate LTG activity, rather than absence of specific enzymes, and essential LTG activities are likely independent of protein-protein interactions, as heterologous expression of a non-native LTG rescues growth of a conditional LTG-null mutant. Lastly, we demonstrate that soluble, uncrosslinked, endopeptidase-dependent peptidoglycan chains, also detected in the wild-type, are enriched in LTG mutants, and that LTG mutants are hypersusceptible to the production of diverse periplasmic polymers. Collectively, our results suggest that LTGs prevent toxic crowding of the periplasm with synthesis-derived peptidoglycan polymers and, contrary to prevailing models, that this autolytic function can be temporally separate from peptidoglycan synthesis.
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Affiliation(s)
- Anna Isabell Weaver
- Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
- Department of Microbiology, Cornell UniversityIthacaUnited States
| | - Laura Alvarez
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Kelly M Rosch
- Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Asraa Ahmed
- Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell UniversityIthacaUnited States
| | - Garrett Sean Wang
- Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Michael S van Nieuwenhze
- Department of Molecular and Cellular Biochemistry, Indiana UniversityBloomingtonSweden
- Department of Chemistry, Indiana UniversityBloomingtonUnited States
| | - Felipe Cava
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
- Department of Microbiology, Cornell UniversityIthacaUnited States
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell UniversityIthacaUnited States
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16
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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17
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Apostolos AJ, Ferraro NJ, Dalesandro BE, Pires MM. SaccuFlow: A High-Throughput Analysis Platform to Investigate Bacterial Cell Wall Interactions. ACS Infect Dis 2021; 7:2483-2491. [PMID: 34291914 DOI: 10.1021/acsinfecdis.1c00255] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Bacterial cell walls are formidable barriers that protect bacterial cells against external insults and oppose internal turgor pressure. While cell wall composition is variable across species, peptidoglycan is the principal component of all cell walls. Peptidoglycan is a mesh-like scaffold composed of cross-linked strands that can be heavily decorated with anchored proteins. The biosynthesis and remodeling of peptidoglycan must be tightly regulated by cells because disruption to this biomacromolecule is lethal. This essentiality is exploited by the human innate immune system in resisting colonization and by a number of clinically relevant antibiotics that target peptidoglycan biosynthesis. Evaluation of molecules or proteins that interact with peptidoglycan can be a complicated and, typically, qualitative effort. We have developed a novel assay platform (SaccuFlow) that preserves the native structure of bacterial peptidoglycan and is compatible with high-throughput flow cytometry analysis. We show that the assay is facile and versatile as demonstrated by its compatibility with sacculi from Gram-positive bacteria, Gram-negative bacteria, and mycobacteria. Finally, we highlight the utility of this assay to assess the activity of sortase A from Staphylococcus aureus against potential antivirulence agents.
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Affiliation(s)
- Alexis J. Apostolos
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Noel J. Ferraro
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Brianna E. Dalesandro
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Marcos M. Pires
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
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18
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A Potentiometric Electronic Tongue as a Discrimination Tool of Water-Food Indicator/Contamination Bacteria. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9060143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Microorganism assessment plays a key role in food quality and safety control but conventional techniques are costly and/or time consuming. Alternatively, electronic tongues (E-tongues) can fulfill this critical task. Thus, a potentiometric lab-made E-tongue (40 lipid sensor membranes) was used to differentiate four common food contamination bacteria, including two Gram positive (Enterococcus faecalis, Staphylococcus aureus) and two Gram negative (Escherichia coli, Pseudomonas aeruginosa). Principal component analysis and a linear discriminant analysis-simulated annealing algorithm (LDA-SA) showed that the potentiometric signal profiles acquired during the analysis of aqueous solutions containing known amounts of each studied bacteria allowed a satisfactory differentiation of the four bacterial strains. An E-tongue-LDA-SA model (12 non-redundant sensors) correctly classified 98 ± 5% of the samples (repeated K-fold-CV), the satisfactory performance of which can be attributed to the capability of the lipid membranes to establish electrostatic interactions/hydrogen bonds with hydroxyl, amine and/or carbonyl groups, which are comprised in the bacteria outer membranes. Furthermore, multiple linear regression models, based on selected subsets of E-tongue sensors (12–15 sensors), also allowed quantifying the bacteria contents in aqueous solutions (0.993 ± 0.011 ≤ R2 ≤ 0.998 ± 0.005, for repeated K-fold-CV). In conclusion, the E-tongue could be of great value as a preliminary food quality and safety diagnosis tool.
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19
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Modulation of Peptidoglycan Synthesis by Recycled Cell Wall Tetrapeptides. Cell Rep 2021; 31:107578. [PMID: 32348759 DOI: 10.1016/j.celrep.2020.107578] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/12/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022] Open
Abstract
The bacterial cell wall is made of peptidoglycan (PG), a polymer that is essential for the maintenance of cell shape and survival. During growth, bacteria remodel their PG, releasing fragments that are predominantly re-internalized and recycled. Here, we show that Vibrio cholerae recycles PG fragments modified with non-canonical d-amino acids (NCDAA), which lead to the accumulation of cytosolic PG tetrapeptides. We demonstrate that the accumulation of recycled tetrapeptides has two regulatory consequences for the cell wall: reduction of d,d-cross-linkage and reduction of PG synthesis. We further demonstrate that l,d-carboxypeptidases from five different species show a preferential activity for substrates containing canonical (d-alanine) versus non-canonical (d-methionine) d-amino acids, suggesting that the accumulation of intracellular tetrapeptides in NCDAA-rich environments is widespread. Collectively, this work reveals a regulatory role of NCDAA linking PG recycling and synthesis to promote optimal cell wall assembly and composition in the stationary phase.
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20
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Aliashkevich A, Howell M, Brown PJB, Cava F. d-canavanine affects peptidoglycan structure, morphogenesis and fitness in Rhizobiales. Environ Microbiol 2021; 23:5823-5836. [PMID: 33830599 DOI: 10.1111/1462-2920.15513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/25/2021] [Accepted: 04/06/2021] [Indexed: 02/02/2023]
Abstract
The bacterial cell wall is made of peptidoglycan (PG), a polymer that is essential for maintenance of cell shape and survival. Many bacteria alter their PG chemistry as a strategy to adapt their cell wall to external challenges. Therefore, identifying these environmental cues is important to better understand the interplay between microbes and their habitat. Here, we used the soil bacterium Pseudomonas putida to uncover cell wall modulators from plant extracts and found canavanine (CAN), a non-proteinogenic amino acid. We demonstrated that cell wall chemical editing by CAN is licensed by P. putida BSAR, a broad-spectrum racemase which catalyses production of dl-CAN from l-CAN, which is produced by many legumes. Importantly, d-CAN diffuses to the extracellular milieu thereby having a potential impact on other organisms inhabiting the same niche. Our results show that d-CAN alters dramatically the PG structure of Rhizobiales (e.g., Agrobacterium tumefaciens, Sinorhizobium meliloti), impairing PG crosslinkage and cell division. Using A. tumefaciens, we demonstrated that the detrimental effect of d-CAN is suppressed by a single amino acid substitution in the cell division PG transpeptidase penicillin binding protein 3a. Collectively, this work highlights the role of amino acid racemization in cell wall chemical editing and fitness.
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Affiliation(s)
- Alena Aliashkevich
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Matthew Howell
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65201, USA.,Department of Biology and Environmental Science, Westminster College, Fulton, MO, 65251, USA
| | - Pamela J B Brown
- Division of Biological Sciences, University of Missouri, Columbia, MO, 65201, USA
| | - Felipe Cava
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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21
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Wang J, Alvarez L, Bulgheresi S, Cava F, den Blaauwen T. PBP4 Is Likely Involved in Cell Division of the Longitudinally Dividing Bacterium Candidatus Thiosymbion Oneisti. Antibiotics (Basel) 2021; 10:antibiotics10030274. [PMID: 33803189 PMCID: PMC7999549 DOI: 10.3390/antibiotics10030274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/24/2021] [Accepted: 03/06/2021] [Indexed: 11/16/2022] Open
Abstract
Peptidoglycan (PG) is essential for bacterial survival and maintaining cell shape. The rod-shaped model bacterium Escherichia coli has a set of seven endopeptidases that remodel the PG during cell growth. The gamma proteobacterium Candidatus Thiosymbion oneisti is also rod-shaped and attaches to the cuticle of its nematode host by one pole. It widens and divides by longitudinal fission using the canonical proteins MreB and FtsZ. The PG layer of Ca. T. oneisti has an unusually high peptide cross-linkage of 67% but relatively short glycan chains with an average length of 12 disaccharides. Curiously, it has only two predicted endopeptidases, MepA and PBP4. Cellular localization of symbiont PBP4 by fluorescently labeled antibodies reveals its polar localization and its accumulation at the constriction sites, suggesting that PBP4 is involved in PG biosynthesis during septum formation. Isolated symbiont PBP4 protein shows a different selectivity for β-lactams compared to its homologue from E. coli. Bocillin-FL binding by PBP4 is activated by some β-lactams, suggesting the presence of an allosteric binding site. Overall, our data point to a role of PBP4 in PG cleavage during the longitudinal cell division and to a PG that might have been adapted to the symbiotic lifestyle.
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Affiliation(s)
- Jinglan Wang
- Bacterial Cell Biology & Physiology, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands;
| | - Laura Alvarez
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden; (L.A.); (F.C.)
| | - Silvia Bulgheresi
- Environmental Cell Biology, University of Vienna, Althanstrasse 14 (UZA I), 1090 Vienna, Austria;
| | - Felipe Cava
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden; (L.A.); (F.C.)
| | - Tanneke den Blaauwen
- Bacterial Cell Biology & Physiology, Faculty of Science, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands;
- Correspondence:
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22
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Gilmore MC, Ritzl-Rinkenberger B, Cava F. An updated toolkit for exploring bacterial cell wall structure and dynamics. Fac Rev 2021; 10:14. [PMID: 33659932 PMCID: PMC7894271 DOI: 10.12703/r/10-14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The bacterial cell wall is made primarily from peptidoglycan, a complex biomolecule which forms a bag-like exoskeleton that envelops the cell. As it is unique to bacteria and typically essential for their growth and survival, it represents one of the most successful targets for antibiotics. Although peptidoglycan has been studied intensively for over 50 years, the past decade has seen major steps in our understanding of this molecule because of the advent of new analytical and imaging methods. Here, we outline the most recent developments in tools that have helped to elucidate peptidoglycan structure and dynamics.
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Affiliation(s)
- Michael C Gilmore
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Barbara Ritzl-Rinkenberger
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
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23
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New approaches and techniques for bacterial cell wall analysis. Curr Opin Microbiol 2021; 60:88-95. [PMID: 33631455 DOI: 10.1016/j.mib.2021.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022]
Abstract
Peptidoglycan (PG) has remained for decades in the spotlight of the never-ending battle against pathogenic bacteria as this essential bacterial structure is one of the most successful targets for antibiotics. Most of our current understanding about the composition, architecture, and dynamics of the PG relies on techniques which have experienced great technological and methodological improvements in the past years. Here we summarize recent advances in these methods with the intention to furnish a valuable resource for both PG experts and newcomers.
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L-arabinose induces the formation of viable non-proliferating spheroplasts in Vibrio cholerae. Appl Environ Microbiol 2021; 87:AEM.02305-20. [PMID: 33355111 PMCID: PMC8090878 DOI: 10.1128/aem.02305-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio cholerae, the agent of the deadly human disease cholera, propagates as a curved rod-shaped bacterium in warm waters. It is sensitive to cold, but persists in cold waters under the form of viable but non-dividing coccoidal shaped cells. Additionally, V. cholerae is able to form non-proliferating spherical cells in response to cell wall damage. It was recently reported that L-arabinose, a component of the hemicellulose and pectin of terrestrial plants, stops the growth of V. cholerae. Here, we show that L-arabinose induces the formation of spheroplasts that lose the ability to divide and stop growing in volume over time. However, they remain viable and upon removal of L-arabinose they start expanding in volume, form branched structures and give rise to cells with a normal morphology after a few divisions. We further show that WigKR, a histidine kinase/response regulator pair implicated in the induction of a high expression of cell wall synthetic genes, prevents the lysis of the spheroplasts during growth restart. Finally, we show that the physiological perturbations result from the import and catabolic processing of L-arabinose by the V. cholerae homolog of the E. coli galactose transport and catabolic system. Taken together, our results suggest that the formation of non-growing spherical cells is a common response of Vibrios exposed to detrimental conditions. They also permit to define conditions preventing any physiological perturbation of V. cholerae when using L-arabinose to induce gene expression from the tightly regulated promoter of the Escherichia coli araBAD operon.Importance Vibrios among other bacteria form transient cell wall deficient forms as a response to different stresses and revert to proliferating rods when permissive conditions have been restored. Such cellular forms have been associated to antimicrobial tolerance, chronic infections and environmental dispersion.The effect of L-Ara on V. cholerae could provide an easily tractable model to study the ability of Vibrios to form viable reversible spheroplasts. Indeed, the quick transition to spheroplasts and reversion to proliferating rods by addition or removal of L-Ara is ideal to understand the genetic program governing this physiological state and the spatial rearrangements of the cellular machineries during cell shape transitions.
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García-Del Portillo F. Building peptidoglycan inside eukaryotic cells: A view from symbiotic and pathogenic bacteria. Mol Microbiol 2020; 113:613-626. [PMID: 32185832 PMCID: PMC7154730 DOI: 10.1111/mmi.14452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/08/2019] [Accepted: 01/09/2020] [Indexed: 12/13/2022]
Abstract
The peptidoglycan (PG), as the exoskeleton of most prokaryotes, maintains a defined shape and ensures cell integrity against the high internal turgor pressure. These important roles have attracted researchers to target PG metabolism in order to control bacterial infections. Most studies, however, have been performed in bacteria grown under laboratory conditions, leading to only a partial view on how the PG is synthetized in natural environments. As a case in point, PG metabolism and its regulation remain poorly understood in symbiotic and pathogenic bacteria living inside eukaryotic cells. This review focuses on the PG metabolism of intracellular bacteria, emphasizing the necessity of more in vivo studies involving the analysis of enzymes produced in the intracellular niche and the isolation of PG from bacteria residing within eukaryotic cells. The review also points to persistent infections caused by some intracellular bacterial pathogens and the extent at which the PG could contribute to establish such physiological state. Based on recent evidences, I speculate on the idea that certain structural features of the PG may facilitate attenuation of intracellular growth. Lastly, I discuss recent findings in endosymbionts supporting a cooperation between host and bacterial enzymes to assemble a mature PG.
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Alvarez L, Cordier B, Van Teeffelen S, Cava F. Analysis of Gram-negative Bacteria Peptidoglycan by Ultra-performance Liquid Chromatography. Bio Protoc 2020; 10:e3780. [PMID: 33659436 DOI: 10.21769/bioprotoc.3780] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/20/2020] [Accepted: 09/21/2020] [Indexed: 11/02/2022] Open
Abstract
Bacteria are surrounded by a protective peptidoglycan cell wall. Provided that this structure and the enzymes involved are the preferred target for our most successful antibiotics, determining its structural and chemical complexity is of the highest interest. Traditionally, high-performance liquid chromatography (HPLC) analyses have been performed, but these methods are very time consuming in terms of sample preparation and chromatographic separation. Here we describe an optimized method for preparation of Gram-negative bacteria peptidoglycan and its subsequent analysis by ultra-performance liquid chromatography (UPLC). The use of UPLC in peptidoglycan analyses provides a dramatic reduction of the sample volume and hands-on time required and, furthermore, permits in-line mass spectrometry (MS) of the UPLC resolved muropeptides, thus facilitating their identification. This method improves our capability to perform high throughput analysis to better understand the cell-wall biology.
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Affiliation(s)
- Laura Alvarez
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Baptiste Cordier
- Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
| | - Sven Van Teeffelen
- Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
| | - Felipe Cava
- Department of Molecular Biology, Umeå University, Umeå, Sweden
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Sexton DL, Herlihey FA, Brott AS, Crisante DA, Shepherdson E, Clarke AJ, Elliot MA. Roles of LysM and LytM domains in resuscitation-promoting factor (Rpf) activity and Rpf-mediated peptidoglycan cleavage and dormant spore reactivation. J Biol Chem 2020; 295:9171-9182. [PMID: 32434927 PMCID: PMC7335776 DOI: 10.1074/jbc.ra120.013994] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/15/2020] [Indexed: 11/06/2022] Open
Abstract
Bacterial dormancy can take many forms, including formation of Bacillus endospores, Streptomyces exospores, and metabolically latent Mycobacterium cells. In the actinobacteria, including the streptomycetes and mycobacteria, the rapid resuscitation from a dormant state requires the activities of a family of cell-wall lytic enzymes called resuscitation-promoting factors (Rpfs). Whether Rpf activity promotes resuscitation by generating peptidoglycan fragments (muropeptides) that function as signaling molecules for spore germination or by simply remodeling the dormant cell wall has been the subject of much debate. Here, to address this question, we used mutagenesis and peptidoglycan binding and cleavage assays to first gain broader insight into the biochemical function of diverse Rpf enzymes. We show that their LysM and LytM domains enhance Rpf enzyme activity; their LytM domain and, in some cases their LysM domain, also promoted peptidoglycan binding. We further demonstrate that the Rpfs function as endo-acting lytic transglycosylases, cleaving within the peptidoglycan backbone. We also found that unlike in other systems, Rpf activity in the streptomycetes is not correlated with peptidoglycan-responsive Ser/Thr kinases for cell signaling, and the germination of rpf mutant strains could not be stimulated by the addition of known germinants. Collectively, these results suggest that in Streptomyces, Rpfs have a structural rather than signaling function during spore germination, and that in the actinobacteria, any signaling function associated with spore resuscitation requires the activity of additional yet to be identified enzymes.
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Affiliation(s)
- Danielle L Sexton
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada
| | - Francesca A Herlihey
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Ashley S Brott
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - David A Crisante
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada
| | - Evan Shepherdson
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Marie A Elliot
- Michael G. DeGroote Institute for Infectious Disease Research and Department of Biology, McMaster University, Hamilton, Canada.
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28
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Abstract
The NlpC/p60-family of peptidoglycan hydrolases are key enzymes that facilitate bacterial cell division and also modulate microbe-host interactions. These endopeptidases utilize conserved Cys-His residues in their active site and are expressed in most bacterial species as well as some eukaryotes. Here we describe methods for biochemical analysis of Enterococcus faecium SagA-NlpC/p60 peptidoglycan hydrolase activity (Kim et al., 2019; Rangan et al., 2016), which includes recombinant protein preparation and biochemical analysis using both gel-based and LC-MS profiling of peptidoglycan fragments. These protocols should also facilitate the biochemical analysis of other NlpC/p60 peptidoglycan hydrolases.
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Gautam S, Kim T, Howell R, Spiegel DA. Fluorescent stem peptide mimics: In situ probes for peptidoglycan crosslinking. Methods Enzymol 2020; 638:57-67. [PMID: 32416921 DOI: 10.1016/bs.mie.2020.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Understanding the mechanisms of bacterial cell wall synthesis is essential for microbiology and medicine alike. A key step in this process is peptidoglycan crosslinking, which confers mechanical strength to the cell wall and represents a target for numerous classes of antibiotics. However, the biology of crosslinking remains poorly understood due to a lack of tools for studying the reaction in vivo. Recently, we developed a class of synthetic probes called fluorescent stem peptide mimics (FSPMs) that meet this need, allowing quantification and localization of crosslinking activity in live bacteria. We have utilized FSPMs to describe novel aspects of peptidoglycan synthesis in the human pathogen, Staphylococcus aureus. To enable wider use of our methodology, we provide detailed protocols herein for the synthesis of FSPMs, labeling of live bacteria, and evaluation of crosslinking by flow cytometry and super-resolution microscopy. We believe that FSPMs, together with complementary biosynthetic probes and traditional bacteriologic methods, will help to advance our understanding of peptidoglycan biology and accelerate the search for new antibiotics.
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Affiliation(s)
- Samir Gautam
- Yale University School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care and Sleep Medicine, New Haven, CT, United States; Yale University, Department of Chemistry, New Haven, CT, United States
| | - Taehan Kim
- Yale University, Department of Chemistry, New Haven, CT, United States
| | - Rebecca Howell
- Yale University, Department of Chemistry, New Haven, CT, United States
| | - David A Spiegel
- Yale University, Department of Chemistry, New Haven, CT, United States.
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30
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Do T, Page JE, Walker S. Uncovering the activities, biological roles, and regulation of bacterial cell wall hydrolases and tailoring enzymes. J Biol Chem 2020; 295:3347-3361. [PMID: 31974163 DOI: 10.1074/jbc.rev119.010155] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria account for 1000-fold more biomass than humans. They vary widely in shape and size. The morphological diversity of bacteria is due largely to the different peptidoglycan-based cell wall structures that encase bacterial cells. Although the basic structure of peptidoglycan is highly conserved, consisting of long glycan strands that are cross-linked by short peptide chains, the mature cell wall is chemically diverse. Peptidoglycan hydrolases and cell wall-tailoring enzymes that regulate glycan strand length, the degree of cross-linking, and the addition of other modifications to peptidoglycan are central in determining the final architecture of the bacterial cell wall. Historically, it has been difficult to biochemically characterize these enzymes that act on peptidoglycan because suitable peptidoglycan substrates were inaccessible. In this review, we discuss fundamental aspects of bacterial cell wall synthesis, describe the regulation and diverse biochemical and functional activities of peptidoglycan hydrolases, and highlight recently developed methods to make and label defined peptidoglycan substrates. We also review how access to these substrates has now enabled biochemical studies that deepen our understanding of how bacterial cell wall enzymes cooperate to build a mature cell wall. Such improved understanding is critical to the development of new antibiotics that disrupt cell wall biogenesis, a process essential to the survival of bacteria.
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Affiliation(s)
- Truc Do
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Julia E Page
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115.
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31
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Vigouroux A, Cordier B, Aristov A, Alvarez L, Özbaykal G, Chaze T, Oldewurtel ER, Matondo M, Cava F, Bikard D, van Teeffelen S. Class-A penicillin binding proteins do not contribute to cell shape but repair cell-wall defects. eLife 2020; 9:e51998. [PMID: 31904338 PMCID: PMC7002073 DOI: 10.7554/elife.51998] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 01/04/2020] [Indexed: 01/06/2023] Open
Abstract
Cell shape and cell-envelope integrity of bacteria are determined by the peptidoglycan cell wall. In rod-shaped Escherichia coli, two conserved sets of machinery are essential for cell-wall insertion in the cylindrical part of the cell: the Rod complex and the class-A penicillin-binding proteins (aPBPs). While the Rod complex governs rod-like cell shape, aPBP function is less well understood. aPBPs were previously hypothesized to either work in concert with the Rod complex or to independently repair cell-wall defects. First, we demonstrate through modulation of enzyme levels that aPBPs do not contribute to rod-like cell shape but are required for mechanical stability, supporting their independent activity. By combining measurements of cell-wall stiffness, cell-wall insertion, and PBP1b motion at the single-molecule level, we then present evidence that PBP1b, the major aPBP, contributes to cell-wall integrity by repairing cell wall defects.
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Affiliation(s)
- Antoine Vigouroux
- Microbial Morphogenesis and Growth LaboratoryInstitut PasteurParisFrance
- Synthetic Biology LaboratoryInstitut PasteurParisFrance
- Université Paris Descartes, Sorbonne-Paris-CitéParisFrance
| | - Baptiste Cordier
- Microbial Morphogenesis and Growth LaboratoryInstitut PasteurParisFrance
| | - Andrey Aristov
- Microbial Morphogenesis and Growth LaboratoryInstitut PasteurParisFrance
| | - Laura Alvarez
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular BiologyUmeå UniversityUmeåSweden
| | - Gizem Özbaykal
- Microbial Morphogenesis and Growth LaboratoryInstitut PasteurParisFrance
- Université Paris Diderot, Sorbonne-Paris-CitéParisFrance
| | | | | | | | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular BiologyUmeå UniversityUmeåSweden
| | - David Bikard
- Synthetic Biology LaboratoryInstitut PasteurParisFrance
| | - Sven van Teeffelen
- Microbial Morphogenesis and Growth LaboratoryInstitut PasteurParisFrance
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32
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Woldemeskel SA, Daitch AK, Alvarez L, Panis G, Zeinert R, Gonzalez D, Smith E, Collier J, Chien P, Cava F, Viollier PH, Goley ED. The conserved transcriptional regulator CdnL is required for metabolic homeostasis and morphogenesis in Caulobacter. PLoS Genet 2020; 16:e1008591. [PMID: 31961855 PMCID: PMC6994171 DOI: 10.1371/journal.pgen.1008591] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 01/31/2020] [Accepted: 01/01/2020] [Indexed: 12/23/2022] Open
Abstract
Bacterial growth and division require regulated synthesis of the macromolecules used to expand and replicate components of the cell. Transcription of housekeeping genes required for metabolic homeostasis and cell proliferation is guided by the sigma factor σ70. The conserved CarD-like transcriptional regulator, CdnL, associates with promoter regions where σ70 localizes and stabilizes the open promoter complex. However, the contributions of CdnL to metabolic homeostasis and bacterial physiology are not well understood. Here, we show that Caulobacter crescentus cells lacking CdnL have severe morphological and growth defects. Specifically, ΔcdnL cells grow slowly in both rich and defined media, and are wider, more curved, and have shorter stalks than WT cells. These defects arise from transcriptional downregulation of most major classes of biosynthetic genes, leading to significant decreases in the levels of critical metabolites, including pyruvate, α-ketoglutarate, ATP, NAD+, UDP-N-acetyl-glucosamine, lipid II, and purine and pyrimidine precursors. Notably, we find that ΔcdnL cells are glutamate auxotrophs, and ΔcdnL is synthetic lethal with other genetic perturbations that limit glutamate synthesis and lipid II production. Our findings implicate CdnL as a direct and indirect regulator of genes required for metabolic homeostasis that impacts morphogenesis through availability of lipid II and other metabolites.
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Affiliation(s)
- Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Allison K. Daitch
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Laura Alvarez
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Gaël Panis
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Rilee Zeinert
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, MA, United States of America
| | - Diego Gonzalez
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | - Erika Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Justine Collier
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, MA, United States of America
| | - Felipe Cava
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Patrick H. Viollier
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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33
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Torrens G, Hernández SB, Ayala JA, Moya B, Juan C, Cava F, Oliver A. Regulation of AmpC-Driven β-Lactam Resistance in Pseudomonas aeruginosa: Different Pathways, Different Signaling. mSystems 2019; 4:e00524-19. [PMID: 31796566 PMCID: PMC6890930 DOI: 10.1128/msystems.00524-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/09/2019] [Indexed: 02/06/2023] Open
Abstract
The hyperproduction of the chromosomal AmpC β-lactamase is the main mechanism driving β-lactam resistance in Pseudomonas aeruginosa, one of the leading opportunistic pathogens causing nosocomial acute and chronic infections in patients with underlying respiratory diseases. In the current scenario of the shortage of effective antipseudomonal drugs, understanding the molecular mechanisms mediating AmpC hyperproduction in order to develop new therapeutics against this fearsome pathogen is of great importance. It has been accepted for decades that certain cell wall-derived soluble fragments (muropeptides) modulate AmpC production by complexing with the transcriptional regulator AmpR and acquiring different conformations that activate/repress ampC expression. However, these peptidoglycan-derived signals have never been characterized in the highly prevalent P. aeruginosa stable AmpC hyperproducer mutants. Here, we demonstrate that the previously described fragments enabling the transient ampC hyperexpression during cefoxitin induction (1,6-anhydro-N-acetylmuramyl-pentapeptides) also underlie the dacB (penicillin binding protein 4 [PBP4]) mutation-driven stable hyperproduction but differ from the 1,6-anhydro-N-acetylmuramyl-tripeptides notably overaccumulated in the ampD knockout mutant. In addition, a simultaneous greater accumulation of both activators appears linked to higher levels of AmpC hyperproduction, although our results suggest a much stronger AmpC-activating potency for the 1,6-anhydro-N-acetylmuramyl-pentapeptide. Collectively, our results propose a model of AmpC control where the activator fragments, with qualitative and quantitative particularities depending on the pathways and levels of β-lactamase production, dominate over the repressor (UDP-N-acetylmuramyl-pentapeptide). This study represents a major step in understanding the foundations of AmpC-dependent β-lactam resistance in P. aeruginosa, potentially useful to open new therapeutic conceptions intended to interfere with the abovementioned cell wall-derived signaling.IMPORTANCE The extensive use of β-lactam antibiotics and the bacterial adaptive capacity have led to the apparently unstoppable increase of antimicrobial resistance, one of the current major global health challenges. In the leading nosocomial pathogen Pseudomonas aeruginosa, the mutation-driven AmpC β-lactamase hyperproduction stands out as the main resistance mechanism, but the molecular cues enabling this system have remained elusive until now. Here, we provide for the first time direct and quantitative information about the soluble cell wall-derived fragments accounting for the different levels and pathways of AmpC hyperproduction. Based on these results, we propose a hierarchical model of signals which ultimately govern ampC hyperexpression and resistance.
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Affiliation(s)
- Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Sara Belén Hernández
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Juan Alfonso Ayala
- Departamento de Virología y Microbiología, Centro de Biología Molecular Severo Ochoa, Madrid, Spain
| | - Bartolome Moya
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
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34
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Muropeptides Stimulate Growth Resumption from Stationary Phase in Escherichia coli. Sci Rep 2019; 9:18043. [PMID: 31792329 PMCID: PMC6888817 DOI: 10.1038/s41598-019-54646-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 11/18/2019] [Indexed: 12/19/2022] Open
Abstract
When nutrients run out, bacteria enter a dormant metabolic state. This low or undetectable metabolic activity helps bacteria to preserve their scant reserves for the future needs, yet it also diminishes their ability to scan the environment for new growth-promoting substrates. However, neighboring microbial growth is a reliable indicator of a favorable environment and can thus serve as a cue for exiting dormancy. Here we report that for Escherichia coli and Pseudomonas aeruginosa this cue is provided by the basic peptidoglycan unit (i.e. muropeptide). We show that several forms of muropeptides from a variety of bacterial species can stimulate growth resumption of dormant cells and the sugar – peptide bond is crucial for this activity. These results, together with previous research that identifies muropeptides as a germination signal for bacterial spores, and their detection by mammalian immune cells, show that muropeptides are a universal cue for bacterial growth.
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35
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Lim Y, Shiver AL, Khariton M, Lane KM, Ng KM, Bray SR, Qin J, Huang KC, Wang B. Mechanically resolved imaging of bacteria using expansion microscopy. PLoS Biol 2019; 17:e3000268. [PMID: 31622337 PMCID: PMC6797083 DOI: 10.1371/journal.pbio.3000268] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 09/05/2019] [Indexed: 11/19/2022] Open
Abstract
Imaging dense and diverse microbial communities has broad applications in basic microbiology and medicine, but remains a grand challenge due to the fact that many species adopt similar morphologies. While prior studies have relied on techniques involving spectral labeling, we have developed an expansion microscopy method (μExM) in which bacterial cells are physically expanded prior to imaging. We find that expansion patterns depend on the structural and mechanical properties of the cell wall, which vary across species and conditions. We use this phenomenon as a quantitative and sensitive phenotypic imaging contrast orthogonal to spectral separation to resolve bacterial cells of different species or in distinct physiological states. Focusing on host-microbe interactions that are difficult to quantify through fluorescence alone, we demonstrate the ability of μExM to distinguish species through an in vitro defined community of human gut commensals and in vivo imaging of a model gut microbiota, and to sensitively detect cell-envelope damage caused by antibiotics or previously unrecognized cell-to-cell phenotypic heterogeneity among pathogenic bacteria as they infect macrophages.
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Affiliation(s)
- Youngbin Lim
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Anthony L. Shiver
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Margarita Khariton
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Keara M. Lane
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Katharine M. Ng
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Samuel R. Bray
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Jian Qin
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Chan Zuckerberg Biohub, San Francisco, California, United States of America
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
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36
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Torrens G, Escobar-Salom M, Pol-Pol E, Camps-Munar C, Cabot G, López-Causapé C, Rojo-Molinero E, Oliver A, Juan C. Comparative Analysis of Peptidoglycans From Pseudomonas aeruginosa Isolates Recovered From Chronic and Acute Infections. Front Microbiol 2019; 10:1868. [PMID: 31507543 PMCID: PMC6719521 DOI: 10.3389/fmicb.2019.01868] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 07/29/2019] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is one of the first causes of acute nosocomial and chronic infections in patients with underlying respiratory pathologies such as cystic fibrosis (CF). It has been proposed that P. aeruginosa accumulates mutations driving to peptidoglycan modifications throughout the development of the CF-associated infection, as a strategy to lower the immune detection hence ameliorating the chronic persistence. As well, some studies dealing with peptidoglycan modifications driving to a better survival within the host have been published in other gram-negatives. According to these facts, the gram-negative peptidoglycan could be considered as a pathogen-associated molecular pattern with very important implications regarding the host’s detection-response, worthy to dissect in detail. For this reason, in this work we characterized for the first time the peptidoglycans of three large collections [early CF, late CF and acute infection (bloodstream) P. aeruginosa strains] from qualitative (HPLC), quantitative and inflammatory capacity-related perspectives. The final goal was to identify composition trends potentially supporting the cited strategy of evasion/resistance to the immune system and providing information regarding the differential intrinsic adaptation depending on the type of infection. Although we found several punctual strain-specific particularities, our results indicated a high degree of inter-collection uniformity in the peptidoglycan-related features and the absence of trends amongst the strains studied here. These results suggest that the peptidoglycan of P. aeruginosa is a notably conserved structure in natural isolates regardless of transitory changes that some external conditions could force. Finally, the inverse correlation between the relative amount of stem pentapeptides within the murein sacculus and the resistance to immune lytic attacks against the peptidoglycan was also suggested by our results. Altogether, this work is a major step ahead to understand the biology of peptidoglycan from P. aeruginosa natural strains, hopefully useful in future for therapeutic alternatives design.
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Affiliation(s)
- Gabriel Torrens
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - María Escobar-Salom
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Elisabet Pol-Pol
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Cristina Camps-Munar
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Gabriel Cabot
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Carla López-Causapé
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Estrella Rojo-Molinero
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Antonio Oliver
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Carlos Juan
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
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Dimovska Nilsson K, Palm M, Hood J, Sheriff J, Farewell A, Fletcher JS. Chemical Changes On, and Through, The Bacterial Envelope in Escherichia coli Mutants Exhibiting Impaired Plasmid Transfer Identified Using Time-of-Flight Secondary Ion Mass Spectrometry. Anal Chem 2019; 91:11355-11361. [PMID: 31359753 DOI: 10.1021/acs.analchem.9b02533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) using a (CO2)6k+ gas cluster ion beam (GCIB) was used to analyze Escherichia coli mutants previously identified as having impaired plasmid transfer capability related to the spread of antibiotic resistance. The subset of mutants selected were expected to result in changes in the bacterial envelope composition through the deletion of genes encoding for FabF, DapF, and Lpp, where the surface sensitivity of ToF-SIMS can be most useful. Analysis of arrays of spotted bacteria allowed changes in the lipid composition of the bacteria to be elucidated using multivariate analysis and confirmed through imaging of individual ion signals. Significant changes in chemical composition were observed, including a surprising loss of cyclopropanated fatty acids in the fabF mutant where FabF is associated with the elongation of FA(16:1) to FA(18:1) and not cyclopropane formation. The ability of the GCIB to generate increased higher mass signals from biological samples allowed intact lipid A (m/z 1796) to be detected on the bacteria and, despite a 40 keV impact energy, depth profiled through the bacterial envelope along with other high mass ions including species at m/z 1820 and 2428, attributed to ECACYC, that were only observed below the surface of the bacteria and were notably absent in the depth profile of the lpp mutant. The analysis provides new insights into the action of the specific pathways targeted in this study and paves the way for whole new avenues for the characterization of intact molecules within the bacterial envelope.
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Affiliation(s)
- Kelly Dimovska Nilsson
- Department of Chemistry and Molecular Biology , University of Gothenburg , Gothenburg 405 30 , Sweden
| | - Martin Palm
- Department of Chemistry and Molecular Biology , University of Gothenburg , Gothenburg 405 30 , Sweden.,Centre for Antibiotic Resistance Research , University of Gothenburg , Gothenburg 405 30 , Sweden
| | - James Hood
- School of Engineering , Newcastle University , Newcastle upon Tyne NE1 7RU , United Kingdom
| | - Jake Sheriff
- School of Engineering , Newcastle University , Newcastle upon Tyne NE1 7RU , United Kingdom
| | - Anne Farewell
- Department of Chemistry and Molecular Biology , University of Gothenburg , Gothenburg 405 30 , Sweden.,Centre for Antibiotic Resistance Research , University of Gothenburg , Gothenburg 405 30 , Sweden
| | - John S Fletcher
- Department of Chemistry and Molecular Biology , University of Gothenburg , Gothenburg 405 30 , Sweden
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Chauhan D, Srivastava PA, Ritzl B, Yennamalli RM, Cava F, Priyadarshini R. Amino Acid-Dependent Alterations in Cell Wall and Cell Morphology of Deinococcus indicus DR1. Front Microbiol 2019; 10:1449. [PMID: 31333600 PMCID: PMC6618347 DOI: 10.3389/fmicb.2019.01449] [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: 02/24/2019] [Accepted: 06/11/2019] [Indexed: 11/13/2022] Open
Abstract
Deinococcus radiodurans exhibits growth medium-dependent morphological variation in cell shape, but there is no evidence whether this phenomenon is observed in other members of the Deinococcaceae family. In this study, we isolated a red-pigmented, aerobic, Deinococcus indicus strain DR1 from Dadri wetland, India. This D. indicus strain exhibited cell–morphology transition from rod-shaped cells to multi-cell chains in a growth-medium-dependent fashion. In response to addition of 1% casamino acids in the minimal growth medium, rod-shaped cells formed multi-cell chains. Addition of all 20 amino acids to the minimal medium was able to recapitulate the phenotype. Specifically, a combination of L-methionine, L-lysine, L-aspartate, and L-threonine caused morphological alterations. The transition from rod shape to multi-cell chains is due to delay in daughter cell separation after cell division. Minimal medium supplemented with L-ornithine alone was able to cause cell morphology changes. Furthermore, a comparative UPLC analysis of PG fragments isolated from D. indicus cells propagated in different growth media revealed alterations in the PG composition. An increase in the overall cross-linkage of PG was observed in muropeptides from nutrient-rich TSB and NB media versus PYE medium. Overall our study highlights that environmental conditions influence PG composition and cell morphology in D. indicus.
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Affiliation(s)
- Deepika Chauhan
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, India
| | - Pulkit Anupam Srivastava
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, India
| | - Barbara Ritzl
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Ragothaman M Yennamalli
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, India
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Richa Priyadarshini
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, India
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Abstract
BolA family proteins are conserved in Gram-negative bacteria and many eukaryotes. While diverse cellular phenotypes have been linked to this protein family, the molecular pathways through which these proteins mediate their effects are not well described. Here, we investigated the roles of BolA family proteins in Vibrio cholerae, the cholera pathogen. Like Escherichia coli, V. cholerae encodes two BolA proteins, BolA and IbaG. However, in marked contrast to E. coli, where bolA is linked to cell shape and ibaG is not, in V. cholerae, bolA mutants lack morphological defects, whereas ibaG proved critical for the generation and/or maintenance of the pathogen's morphology. Notably, the bizarre-shaped, multipolar, elongated, and wide cells that predominated in exponential-phase ΔibaG V. cholerae cultures were not observed in stationary-phase cultures. The V. cholerae ΔibaG mutant exhibited increased sensitivity to cell envelope stressors, including cell wall-acting antibiotics and bile, and was defective in intestinal colonization. ΔibaG V. cholerae had reduced peptidoglycan and lipid II and altered outer membrane lipids, likely contributing to the mutant's morphological defects and sensitivity to envelope stressors. Transposon insertion sequencing analysis of ibaG's genetic interactions suggested that ibaG is involved in several processes involved in the generation and homeostasis of the cell envelope. Furthermore, copurification studies revealed that IbaG interacts with proteins containing iron-sulfur clusters or involved in their assembly. Collectively, our findings suggest that V. cholerae IbaG controls cell morphology and cell envelope integrity through its role in biogenesis or trafficking of iron-sulfur cluster proteins.IMPORTANCE BolA-like proteins are conserved across prokaryotes and eukaryotes. These proteins have been linked to a variety of phenotypes, but the pathways and mechanisms through which they act have not been extensively characterized. Here, we unraveled the role of the BolA-like protein IbaG in the cholera pathogen Vibrio cholerae The absence of IbaG was associated with dramatic changes in cell morphology, sensitivity to envelope stressors, and intestinal colonization defects. IbaG was found to be required for biogenesis of several components of the V. cholerae cell envelope and to interact with numerous iron-sulfur cluster-containing proteins and factors involved in their assembly. Thus, our findings suggest that IbaG governs V. cholerae cell shape and cell envelope homeostasis through its effects on iron-sulfur proteins and associated pathways. The diversity of processes involving iron-sulfur-containing proteins is likely a factor underlying the range of phenotypes associated with BolA family proteins.
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Porfírio S, Carlson RW, Azadi P. Elucidating Peptidoglycan Structure: An Analytical Toolset. Trends Microbiol 2019; 27:607-622. [DOI: 10.1016/j.tim.2019.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/16/2019] [Accepted: 01/29/2019] [Indexed: 01/04/2023]
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Coxiella burnetii RpoS Regulates Genes Involved in Morphological Differentiation and Intracellular Growth. J Bacteriol 2019; 201:JB.00009-19. [PMID: 30745369 DOI: 10.1128/jb.00009-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 01/30/2019] [Indexed: 12/19/2022] Open
Abstract
Coxiella burnetii, the etiological agent of Q fever, undergoes a unique biphasic developmental cycle where bacteria transition from a replicating (exponential-phase) large cell variant (LCV) form to a nonreplicating (stationary-phase) small cell variant (SCV) form. The alternative sigma factor RpoS is an essential regulator of stress responses and stationary-phase physiology in several bacterial species, including Legionella pneumophila, which has a developmental cycle superficially similar to that of C. burnetii Here, we used a C. burnetii ΔrpoS mutant to define the role of RpoS in intracellular growth and SCV development. Growth yields following infection of Vero epithelial cells or THP-1 macrophage-like cells with the rpoS mutant in the SCV form, but not the LCV form, were significantly lower than that of wild-type bacteria. RNA sequencing and whole-cell mass spectrometry of the C. burnetii ΔrpoS mutant revealed that a substantial portion of the C. burnetii genome is regulated by RpoS during SCV development. Regulated genes include those involved in stress responses, arginine transport, peptidoglycan remodeling, and synthesis of the SCV-specific protein ScvA. Genes comprising the dot/icm locus, responsible for production of the Dot/Icm type 4B secretion system, were also dysregulated in the rpoS mutant. These data were corroborated with independent assays demonstrating that the C. burnetii ΔrpoS strain has increased sensitivity to hydrogen peroxide and carbenicillin and a thinner cell wall/outer membrane complex. Collectively, these results demonstrate that RpoS is an important regulator of genes involved in C. burnetii SCV development and intracellular growth.IMPORTANCE The Q fever bacterium Coxiella burnetii has spore-like environmental stability, a characteristic that contributes to its designation as a potential bioweapon. Stability is likely conferred by a highly resistant, small cell variant (SCV) stationary-phase form that arises during a biphasic developmental cycle. Here, we define the role of the alternative sigma factor RpoS in regulating genes associated with SCV development. Genes involved in stress responses, amino acid transport, cell wall remodeling, and type 4B effector secretion were dysregulated in the rpoS mutant. Cellular impairments included defects in intracellular growth, cell wall structure, and resistance to oxidants. These results support RpoS as a central regulator of the Coxiella developmental cycle and identify developmentally regulated genes involved in morphological differentiation.
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The peptidoglycan and biofilm matrix of Staphylococcus epidermidis undergo structural changes when exposed to human platelets. PLoS One 2019; 14:e0211132. [PMID: 30682094 PMCID: PMC6347161 DOI: 10.1371/journal.pone.0211132] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 01/02/2019] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus epidermidis is a bacterium frequently isolated from contaminated platelet concentrates (PCs), a blood product used to treat bleeding disorders in transfusion patients. PCs offer an accidental niche for colonization of S. epidermidis by forming biofilms and thus avoiding clearance by immune factors present in this milieu. Using biochemical and microscopy techniques, we investigated the structural changes of the peptidoglycan (PG) and the biofilm matrix of S. epidermidis biofilms formed in whole-blood derived PCs compared to biofilms grown in glucose-supplemented trypticase soy broth (TSBg). Both, the PG and the biofilm matrix are primary mechanisms of defense against environmental stress. Here we show that in PCs, the S. epidermidis biofilm matrix is mainly of a proteinaceous nature with extracellular DNA, in contrast to the predominant polysaccharide nature of the biofilm matrix formed in TSBg cultures. PG profile studies demonstrated that the PG of biofilm cells remodels during PC storage displaying fewer muropeptides variants than those observed in TSBg. The PG muropeptides contain two chemical modifications (amidation and O-acetylation) previously associated with resistance to antimicrobial agents by other staphylococci. Our study highlights two key structural features of S. epidermidis that are remodeled when exposed to human platelets and could be used as targets to reduce septic transfusions events.
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The Chaperone Activities of DsbG and Spy Restore Peptidoglycan Biosynthesis in the elyC Mutant by Preventing Envelope Protein Aggregation. J Bacteriol 2018; 200:JB.00245-18. [PMID: 30012727 DOI: 10.1128/jb.00245-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/06/2018] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycan (PG) is the main structural component of bacterial envelopes. It protects bacterial cells against variations in osmotic pressure and cell lysis. The newly discovered Escherichia coli factor ElyC has been shown to be important for peptidoglycan biosynthesis at low temperatures. PG production in ΔelyC mutant cells is totally blocked after a few hours of growth at 21°C, triggering cell lysis. In this study, we took a candidate approach to identify genetic suppressors of the ΔelyC mutant cell lysis phenotype. We identified the periplasmic proteins DsbG and Spy as multicopy suppressors and showed that their overproduction restores PG biosynthesis in the ΔelyC mutant. Interestingly, we found that DsbG acts by a novel mechanism, which is independent of its known reductase activity and substrates. DsbG, like Spy, acts as a chaperone to reduce the amounts of protein aggregates in the envelopes of ΔelyC cells. In fact, we found that the amount of protein aggregates was greater in the ΔelyC mutant than in the wild type. Taken together, our results show a protein-folding defect in the envelope compartments of ΔelyC cells that blocks PG production, and they reveal a new physiological activity of DsbG.IMPORTANCE Peptidoglycan biosynthesis is a dynamic and well-controlled pathway. The molecular assembly of PG and the regulatory pathways ensuring its maintenance are still not well understood. Here we studied the newly discovered Escherichia coli factor ElyC, which is important for PG biosynthesis at low temperatures. We revealed an important protein-folding defect in the ΔelyC mutant and showed that overproduction of the periplasmic chaperone DsbG or Spy was sufficient to correct the protein-folding defect and restore PG biosynthesis. These results show that the PG defect in the absence of ElyC is caused, at least in part, by a protein-folding problem in the cell envelope. Furthermore, we showed, for the first time, that the periplasmic protein DsbG has chaperone activity in vivo.
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Jun S, Si F, Pugatch R, Scott M. Fundamental principles in bacterial physiology-history, recent progress, and the future with focus on cell size control: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:056601. [PMID: 29313526 PMCID: PMC5897229 DOI: 10.1088/1361-6633/aaa628] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Bacterial physiology is a branch of biology that aims to understand overarching principles of cellular reproduction. Many important issues in bacterial physiology are inherently quantitative, and major contributors to the field have often brought together tools and ways of thinking from multiple disciplines. This article presents a comprehensive overview of major ideas and approaches developed since the early 20th century for anyone who is interested in the fundamental problems in bacterial physiology. This article is divided into two parts. In the first part (sections 1-3), we review the first 'golden era' of bacterial physiology from the 1940s to early 1970s and provide a complete list of major references from that period. In the second part (sections 4-7), we explain how the pioneering work from the first golden era has influenced various rediscoveries of general quantitative principles and significant further development in modern bacterial physiology. Specifically, section 4 presents the history and current progress of the 'adder' principle of cell size homeostasis. Section 5 discusses the implications of coarse-graining the cellular protein composition, and how the coarse-grained proteome 'sectors' re-balance under different growth conditions. Section 6 focuses on physiological invariants, and explains how they are the key to understanding the coordination between growth and the cell cycle underlying cell size control in steady-state growth. Section 7 overviews how the temporal organization of all the internal processes enables balanced growth. In the final section 8, we conclude by discussing the remaining challenges for the future in the field.
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Affiliation(s)
- Suckjoon Jun
- Department of Physics, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, United States of America. Section of Molecular Biology, Division of Biology, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, United States of America
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45
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Zhang F, Lu C, Wang M, Yu X, Wei W, Xia Z. A Chiral Sensor Array for Peptidoglycan Biosynthesis Monitoring Based on MoS 2 Nanosheet-Supported Host-Guest Recognitions. ACS Sens 2018; 3:304-312. [PMID: 29299925 DOI: 10.1021/acssensors.7b00676] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Monitoring the dynamic change with respect to chirality and species of amino acids in bacterial peptidoglycan (PG) during cell wall biosynthesis is correlated with bacterial taxonomy, physiology, micropathology, and antibacterial mechanisms. However, this is challenging because reported methods usually lack the ability of chiral analysis with the coexistence of d- and l-amino acids in PG. Here we report a chiral sensor array for PG biosynthesis monitoring through chiral amino acid recognition. Multitypes of host molecule modified MoS2 nanosheets (MNSs) were used as receptor units to achieve more accurate and specific sensing. By applying indicator displacement strategy, the distinct and reproducible fluorescence-response patterns were obtained for linear discriminant analysis (LDA) to accurately discriminate achiral Gly, 19 l-amino acids and the corresponding 19 d-enantiomers simultaneously. The sensor array has also been used for identifying bacterial species and tracking the subtle change of amino acid composition of PG including chirality and species during biosynthesis in different growth status and exogenous d-amino acid stimulation.
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Affiliation(s)
- Feng Zhang
- School of Pharmaceutical
Sciences and Innovative Drug Research Centre, Chongqing University, Chongqing 401331, PR China
| | - Chenwei Lu
- School of Pharmaceutical
Sciences and Innovative Drug Research Centre, Chongqing University, Chongqing 401331, PR China
| | - Min Wang
- School of Pharmaceutical
Sciences and Innovative Drug Research Centre, Chongqing University, Chongqing 401331, PR China
| | - Xinsheng Yu
- School of Pharmaceutical
Sciences and Innovative Drug Research Centre, Chongqing University, Chongqing 401331, PR China
| | - Weili Wei
- School of Pharmaceutical
Sciences and Innovative Drug Research Centre, Chongqing University, Chongqing 401331, PR China
| | - Zhining Xia
- School of Pharmaceutical
Sciences and Innovative Drug Research Centre, Chongqing University, Chongqing 401331, PR China
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46
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Abstract
Most bacteria break down a significant portion of their cell wall peptidoglycan during each round of growth and cell division. This process generates peptidoglycan fragments of various sizes that can either be imported back into the cytoplasm for recycling or released from the cell. Released fragments have been shown to act as microbe-associated molecular patterns for the initiation of immune responses, as triggers for the initiation of mutualistic host-microbe relationships, and as signals for cell-cell communication in bacteria. Characterizing these released peptidoglycan fragments can, therefore, be considered an important step in understanding how microbes communicate with other organisms in their environments. In this chapter, we describe methods for labeling cell wall peptidoglycan, calculating the rate at which peptidoglycan is turned over, and collecting released peptidoglycan to determine the abundance and species of released fragments. Methods are described for both the separation of peptidoglycan fragments by size-exclusion chromatography and further detailed analysis by HPLC.
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47
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Toyoda K, Inui M. Extracytoplasmic function sigma factor σDconfers resistance to environmental stress by enhancing mycolate synthesis and modifying peptidoglycan structures inCorynebacterium glutamicum. Mol Microbiol 2017; 107:312-329. [DOI: 10.1111/mmi.13883] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Koichi Toyoda
- Research institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawa; Kyoto 619-0292 Japan
| | - Masayuki Inui
- Research institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawa; Kyoto 619-0292 Japan
- Graduate School of Biological Sciences; Nara Institute of Science and Technology, 8916-5; Takayama, Ikoma, Nara 630-0101 Japan
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48
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Zhao H, Patel V, Helmann JD, Dörr T. Don't let sleeping dogmas lie: new views of peptidoglycan synthesis and its regulation. Mol Microbiol 2017; 106:847-860. [PMID: 28975672 DOI: 10.1111/mmi.13853] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 12/24/2022]
Abstract
Bacterial cell wall synthesis is the target for some of our most powerful antibiotics and has thus been the subject of intense research focus for more than 50 years. Surprisingly, we still lack a fundamental understanding of how bacteria build, maintain and expand their cell wall. Due to technical limitations, directly testing hypotheses about the coordination and biochemistry of cell wall synthesis enzymes or architecture has been challenging, and interpretation of data has therefore often relied on circumstantial evidence and implicit assumptions. A number of recent papers have exploited new technologies, like single molecule tracking and real-time, high resolution temporal mapping of cell wall synthesis processes, to address fundamental questions of bacterial cell wall biogenesis. The results have challenged established dogmas and it is therefore timely to integrate new data and old observations into a new model of cell wall biogenesis in rod-shaped bacteria.
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Affiliation(s)
- Heng Zhao
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Vaidehi Patel
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Tobias Dörr
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
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Gale RT, Li FKK, Sun T, Strynadka NCJ, Brown ED. B. subtilis LytR-CpsA-Psr Enzymes Transfer Wall Teichoic Acids from Authentic Lipid-Linked Substrates to Mature Peptidoglycan In Vitro. Cell Chem Biol 2017; 24:1537-1546.e4. [PMID: 29107701 DOI: 10.1016/j.chembiol.2017.09.006] [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] [Received: 04/16/2017] [Revised: 08/01/2017] [Accepted: 09/18/2017] [Indexed: 12/11/2022]
Abstract
Gram-positive bacteria endow their peptidoglycan with glycopolymers that are crucial for viability and pathogenesis. However, the cellular machinery that executes this function is not well understood. While decades of genetic and phenotypic work have highlighted the LytR-CpsA-Psr (LCP) family of enzymes as cell-wall glycopolymer transferases, their in vitro characterization has been elusive, largely due to a paucity of tools for functional assays. In this report, we synthesized authentic undecaprenyl diphosphate-linked wall teichoic acid (WTA) intermediates and built an assay system capable of monitoring LCP-mediated glycopolymer transfer. We report that all Bacillus subtilis LCP enzymes anchor WTAs to peptidoglycan in vitro. Furthermore, we probed the catalytic requirements and substrate preferences for these LCP enzymes and elaborated in vitro conditions for facile tests of enzyme function. This work sheds light on the molecular features of glycopolymer transfer and aims to aid drug discovery and development programs exploiting this promising antibacterial target.
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Affiliation(s)
- Robert T Gale
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Franco K K Li
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Tianjun Sun
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada.
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Caccamo PD, Brun YV. The Molecular Basis of Noncanonical Bacterial Morphology. Trends Microbiol 2017; 26:191-208. [PMID: 29056293 DOI: 10.1016/j.tim.2017.09.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/08/2017] [Accepted: 09/28/2017] [Indexed: 01/04/2023]
Abstract
Bacteria come in a wide variety of shapes and sizes. The true picture of bacterial morphological diversity is likely skewed due to an experimental focus on pathogens and industrially relevant organisms. Indeed, most of the work elucidating the genes and molecular processes involved in maintaining bacterial morphology has been limited to rod- or coccal-shaped model systems. The mechanisms of shape evolution, the molecular processes underlying diverse shapes and growth modes, and how individual cells can dynamically modulate their shape are just beginning to be revealed. Here we discuss recent work aimed at advancing our knowledge of shape diversity and uncovering the molecular basis for shape generation in noncanonical and morphologically complex bacteria.
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Affiliation(s)
- Paul D Caccamo
- Department of Biology, Indiana University, 1001 E. 3rd St, Bloomington, IN 47405, USA
| | - Yves V Brun
- Department of Biology, Indiana University, 1001 E. 3rd St, Bloomington, IN 47405, USA.
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