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A synthetic 5,3-cross-link in the cell wall of rod-shaped Gram-positive bacteria. Proc Natl Acad Sci U S A 2021; 118:2100137118. [PMID: 33836615 DOI: 10.1073/pnas.2100137118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Gram-positive bacteria assemble a multilayered cell wall that provides tensile strength to the cell. The cell wall is composed of glycan strands cross-linked by nonribosomally synthesized peptide stems. Herein, we modify the peptide stems of the Gram-positive bacterium Bacillus subtilis with noncanonical electrophilic d-amino acids, which when in proximity to adjacent stem peptides form novel covalent 5,3-cross-links. Approximately 20% of canonical cell-wall cross-links can be replaced with synthetic cross-links. While a low level of synthetic cross-link formation does not affect B. subtilis growth and phenotype, at higher levels cell growth is perturbed and bacteria elongate. A comparison of the accumulation of synthetic cross-links over time in Gram-negative and Gram-positive bacteria highlights key differences between them. The ability to perturb cell-wall architecture with synthetic building blocks provides a novel approach to studying the adaptability, elasticity, and porosity of bacterial cell walls.
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Lisboa J, Pereira C, Rifflet A, Ayala J, Terceti MS, Barca AV, Rodrigues I, Pereira PJB, Osorio CR, García-Del Portillo F, Gomperts Boneca I, do Vale A, Dos Santos NMS. A Secreted NlpC/P60 Endopeptidase from Photobacterium damselae subsp. piscicida Cleaves the Peptidoglycan of Potentially Competing Bacteria. mSphere 2021; 6:e00736-20. [PMID: 33536321 PMCID: PMC7860986 DOI: 10.1128/msphere.00736-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 01/08/2021] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycan (PG) is a major component of the bacterial cell wall, forming a mesh-like structure enwrapping the bacteria that is essential for maintaining structural integrity and providing support for anchoring other components of the cell envelope. PG biogenesis is highly dynamic and requires multiple enzymes, including several hydrolases that cleave glycosidic or amide bonds in the PG. This work describes the structural and functional characterization of an NlpC/P60-containing peptidase from Photobacterium damselae subsp. piscicida (Phdp), a Gram-negative bacterium that causes high mortality of warm-water marine fish with great impact for the aquaculture industry. PnpA ( PhotobacteriumNlpC-like protein A) has a four-domain structure with a hydrophobic and narrow access to the catalytic center and specificity for the γ-d-glutamyl-meso-diaminopimelic acid bond. However, PnpA does not cleave the PG of Phdp or PG of several Gram-negative and Gram-positive bacterial species. Interestingly, it is secreted by the Phdp type II secretion system and degrades the PG of Vibrio anguillarum and Vibrio vulnificus This suggests that PnpA is used by Phdp to gain an advantage over bacteria that compete for the same resources or to obtain nutrients in nutrient-scarce environments. Comparison of the muropeptide composition of PG susceptible and resistant to the catalytic activity of PnpA showed that the global content of muropeptides is similar, suggesting that susceptibility to PnpA is determined by the three-dimensional organization of the muropeptides in the PG.IMPORTANCE Peptidoglycan (PG) is a major component of the bacterial cell wall formed by long chains of two alternating sugars interconnected by short peptides, generating a mesh-like structure that enwraps the bacterial cell. Although PG provides structural integrity and support for anchoring other components of the cell envelope, it is constantly being remodeled through the action of specific enzymes that cleave or join its components. Here, it is shown that Photobacterium damselae subsp. piscicida, a bacterium that causes high mortality in warm-water marine fish, produces PnpA, an enzyme that is secreted into the environment and is able to cleave the PG of potentially competing bacteria, either to gain a competitive advantage and/or to obtain nutrients. The specificity of PnpA for the PG of some bacteria and its inability to cleave others may be explained by differences in the structure of the PG mesh and not by different muropeptide composition.
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Affiliation(s)
- Johnny Lisboa
- Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Cassilda Pereira
- Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Aline Rifflet
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France
- INSERM Groupe Avenir, Paris, France
- CNRS, UMR "Integrated and Molecular Microbiology," Paris, France
| | - Juan Ayala
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Mateus S Terceti
- Departamento de Microbioloxía e Parasitoloxía, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Alba V Barca
- Departamento de Microbioloxía e Parasitoloxía, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Inês Rodrigues
- Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Pedro José Barbosa Pereira
- Biomolecular Structure Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Macromolecular Structure Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Carlos R Osorio
- Departamento de Microbioloxía e Parasitoloxía, Instituto de Acuicultura, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Francisco García-Del Portillo
- Laboratorio de Patógenos Bacterianos Intracelulares, Centro Nacional de Biotecnología (CNB), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Ivo Gomperts Boneca
- Institut Pasteur, Unité Biologie et Génétique de la Paroi Bactérienne, Paris, France
- INSERM Groupe Avenir, Paris, France
- CNRS, UMR "Integrated and Molecular Microbiology," Paris, France
| | - Ana do Vale
- Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
| | - Nuno M S Dos Santos
- Fish Immunology and Vaccinology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Fish Immunology and Vaccinology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
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Zellner B, Mengin-Lecreulx D, Tully B, Gunning WT, Booth R, Huntley JF. A Francisella tularensis L,D-carboxypeptidase plays important roles in cell morphology, envelope integrity, and virulence. Mol Microbiol 2021; 115:1357-1378. [PMID: 33469978 DOI: 10.1111/mmi.14685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022]
Abstract
Francisella tularensis is a Gram-negative, intracellular bacterium that causes the zoonotic disease tularemia. Intracellular pathogens, including F. tularensis, have evolved mechanisms to survive in the harsh environment of macrophages and neutrophils, where they are exposed to cell envelope-damaging molecules. The bacterial cell wall, primarily composed of peptidoglycan (PG), maintains cell morphology, structure, and membrane integrity. Intracellular Gram-negative bacteria protect themselves from macrophage and neutrophil killing by recycling and repairing damaged PG--a process that involves over 50 different PG synthesis and recycling enzymes. Here, we identified a PG recycling enzyme, L,D-carboxypeptidase A (LdcA), of F. tularensis that is responsible for converting PG tetrapeptide stems to tripeptide stems. Unlike E. coli LdcA and most other orthologs, F. tularensis LdcA does not localize to the cytoplasm and also exhibits L,D-endopeptidase activity, converting PG pentapeptide stems to tripeptide stems. Loss of F. tularensis LdcA led to altered cell morphology and membrane integrity, as well as attenuation in a mouse pulmonary infection model and in primary and immortalized macrophages. Finally, an F. tularensis ldcA mutant protected mice against virulent Type A F. tularensis SchuS4 pulmonary challenge.
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Affiliation(s)
- Briana Zellner
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Brenden Tully
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | | | - Robert Booth
- Department of Pathology, University of Toledo, Toledo, OH, USA
| | - Jason F Huntley
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
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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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Hawkins JS, Silvis MR, Koo BM, Peters JM, Osadnik H, Jost M, Hearne CC, Weissman JS, Todor H, Gross CA. Mismatch-CRISPRi Reveals the Co-varying Expression-Fitness Relationships of Essential Genes in Escherichia coli and Bacillus subtilis. Cell Syst 2020; 11:523-535.e9. [PMID: 33080209 PMCID: PMC7704046 DOI: 10.1016/j.cels.2020.09.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/26/2020] [Accepted: 09/25/2020] [Indexed: 11/24/2022]
Abstract
Essential genes are the hubs of cellular networks, but lack of high-throughput methods for titrating gene expression has limited our understanding of the fitness landscapes against which their expression levels are optimized. We developed a modified CRISPRi system leveraging the predictable reduction in efficacy of imperfectly matched sgRNAs to generate defined levels of CRISPRi activity and demonstrated its broad applicability. Using libraries of mismatched sgRNAs predicted to span the full range of knockdown levels, we characterized the expression-fitness relationships of most essential genes in Escherichia coli and Bacillus subtilis. We find that these relationships vary widely from linear to bimodal but are similar within pathways. Notably, despite ∼2 billion years of evolutionary separation between E. coli and B. subtilis, most essential homologs have similar expression-fitness relationships with rare but informative differences. Thus, the expression levels of essential genes may reflect homeostatic or evolutionary constraints shared between the two organisms.
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Affiliation(s)
- John S Hawkins
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Melanie R Silvis
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Byoung-Mo Koo
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jason M Peters
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hendrik Osadnik
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Marco Jost
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Cameron C Hearne
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Horia Todor
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Carol A Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco, CA 94158, USA.
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Mayer VMT, Tomek MB, Figl R, Borisova M, Hottmann I, Blaukopf M, Altmann F, Mayer C, Schäffer C. Utilization of different MurNAc sources by the oral pathogen Tannerella forsythia and role of the inner membrane transporter AmpG. BMC Microbiol 2020; 20:352. [PMID: 33203363 PMCID: PMC7670621 DOI: 10.1186/s12866-020-02006-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 10/12/2020] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The Gram-negative oral pathogen Tannerella forsythia strictly depends on the external supply of the essential bacterial cell wall sugar N-acetylmuramic acid (MurNAc) for survival because of the lack of the common MurNAc biosynthesis enzymes MurA/MurB. The bacterium thrives in a polymicrobial biofilm consortium and, thus, it is plausible that it procures MurNAc from MurNAc-containing peptidoglycan (PGN) fragments (muropeptides) released from cohabiting bacteria during natural PGN turnover or cell death. There is indirect evidence that in T. forsythia, an AmpG-like permease (Tanf_08365) is involved in cytoplasmic muropeptide uptake. In E. coli, AmpG is specific for the import of N-acetylglucosamine (GlcNAc)-anhydroMurNAc(-peptides) which are common PGN turnover products, with the disaccharide portion as a minimal requirement. Currently, it is unclear which natural, complex MurNAc sources T. forsythia can utilize and which role AmpG plays therein. RESULTS We performed a screen of various putative MurNAc sources for T. forsythia mimicking the situation in the natural habitat and compared bacterial growth and cell morphology of the wild-type and a mutant lacking AmpG (T. forsythia ΔampG). We showed that supernatants of the oral biofilm bacteria Porphyromonas gingivalis and Fusobacterium nucleatum, and of E. coli ΔampG, as well as isolated PGN and defined PGN fragments obtained after enzymatic digestion, namely GlcNAc-anhydroMurNAc(-peptides) and GlcNAc-MurNAc(-peptides), could sustain growth of T. forsythia wild-type, while T. forsythia ΔampG suffered from growth inhibition. In supernatants of T. forsythia ΔampG, the presence of GlcNAc-anhMurNAc and, unexpectedly, also GlcNAc-MurNAc was revealed by tandem mass spectrometry analysis, indicating that both disaccharides are substrates of AmpG. The importance of AmpG in the utilization of PGN fragments as MurNAc source was substantiated by a significant ampG upregulation in T. forsythia cells cultivated with PGN, as determined by quantitative real-time PCR. Further, our results indicate that PGN-degrading amidase, lytic transglycosylase and muramidase activities in a T. forsythia cell extract are involved in PGN scavenging. CONCLUSION T. forsythia metabolizes intact PGN as well as muropeptides released from various bacteria and the bacterium's inner membrane transporter AmpG is essential for growth on these MurNAc sources, and, contrary to the situation in E. coli, imports both, GlcNAc-anhMurNAc and GlcNAc-MurNAc fragments.
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Affiliation(s)
- Valentina M T Mayer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Vienna, Austria
| | - Markus B Tomek
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Vienna, Austria
| | - Rudolf Figl
- Department of Chemistry, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Marina Borisova
- Department of Biology, Eberhard Karls Universität Tübingen, Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Tübingen, Germany
| | - Isabel Hottmann
- Department of Biology, Eberhard Karls Universität Tübingen, Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Tübingen, Germany
| | - Markus Blaukopf
- Department of Chemistry, Institute of Organic Chemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Friedrich Altmann
- Department of Chemistry, Institute of Biochemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Christoph Mayer
- Department of Biology, Eberhard Karls Universität Tübingen, Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Tübingen, Germany.
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Vienna, Austria.
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Zhang Z, Yu F, Zou Y, Qiu Y, Wu A, Jiang T, Peng Y. Phage protein receptors have multiple interaction partners and high expressions. Bioinformatics 2020; 36:2975-2979. [PMID: 32096819 DOI: 10.1093/bioinformatics/btaa123] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/07/2020] [Accepted: 02/18/2020] [Indexed: 02/04/2023] Open
Abstract
MOTIVATION Receptors on host cells play a critical role in viral infection. How phages select receptors is still unknown. RESULTS Here, we manually curated a high-quality database named phageReceptor, including 427 pairs of phage-host receptor interactions, 341 unique viral species or sub-species and 69 bacterial species. Sugars and proteins were most widely used by phages as receptors. The receptor usage of phages in Gram-positive bacteria was different from that in Gram-negative bacteria. Most protein receptors were located on the outer membrane. The phage protein receptors (PPRs) were highly diverse in their structures, and had little sequence identity and no common protein domain with mammalian virus receptors. Further functional characterization of PPRs in Escherichia coli showed that they had larger node degrees and betweennesses in the protein-protein interaction network, and higher expression levels, than other outer membrane proteins, plasma membrane proteins or other intracellular proteins. These findings were consistent with what observed for mammalian virus receptors reported in previous studies, suggesting that viral protein receptors tend to have multiple interaction partners and high expressions. The study deepens our understanding of virus-host interactions. AVAILABILITY AND IMPLEMENTATION phageReceptor is publicly available from: http://www.computationalbiology.cn/phageReceptor/index.html. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Zheng Zhang
- College of Biology, Hunan Provincial Key Laboratory of Medical Virology, Hunan University, Changsha 410082, China
| | - Fen Yu
- College of Biology, Hunan Provincial Key Laboratory of Medical Virology, Hunan University, Changsha 410082, China
| | - Yuanqiang Zou
- Changsha Qiangze Biotech Co., Ltd, Changsha 410000, China
| | - Ye Qiu
- College of Biology, Hunan Provincial Key Laboratory of Medical Virology, Hunan University, Changsha 410082, China
| | - Aiping Wu
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China.,Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123, China
| | - Taijiao Jiang
- Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China.,Suzhou Institute of Systems Medicine, Suzhou, Jiangsu 215123, China
| | - Yousong Peng
- College of Biology, Hunan Provincial Key Laboratory of Medical Virology, Hunan University, Changsha 410082, China
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Han D, Yan Y, Bian X, Wang J, Zhao M, Duan X, Kong L, Cheng W, Ding S. A novel electrochemical biosensor based on peptidoglycan and platinum-nickel-copper nano-cube for rapid detection of Gram-positive bacteria. Mikrochim Acta 2020; 187:607. [PMID: 33052497 DOI: 10.1007/s00604-020-04581-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/29/2020] [Indexed: 12/28/2022]
Abstract
A novel non-enzyme electrochemical biosensor for the rapid detection of Gram-positive bacteria has been constructed that relys on a stable and efficient combination between the peptidoglycan layer and platinum-nickel-copper nanocubes (Pt-Ni-Cu NCs). Briefly, bacteria were first captured by a specific antibody. Then, the electrochemical signal materials (Pt-Ni-Cu NCs) were bound to the bacteria peptidoglycan layer using specific structural and surface features. The rapid and sensitive bacterial detection was then achieved using intrinsic electrochemical characteristics and superoxidase-like activity of the Pt-Ni-Cu NCs. Moreover, the nature of peptidoglycan covering the whole bacteria provided the premise for signal amplification. Under optimal conditions, the electrochemical signal variation was proportional to the concentration of bacteria ranging from 1.5 × 102 to 1.5 × 108 CFU/mL with a detection limit of 42 CFU/mL using a working potential of - 0.4 V. This electrochemical biosensor has been successfully applied to detect bacteria concentrations in urine samples, and the recoveries range from 90.4 to 107%. The proposed biosensor could be applied for broad-spectrum detection of Gram-positive bacteria since most Gram-positive bacteria possess a thick peptidoglycan layer. The developed electrochemical biosensing strategy might be used as a potential tool for clinical pathogenic bacteria detection and point-of-care testing (POCT).
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Affiliation(s)
- Daobin Han
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Yurong Yan
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Xintong Bian
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Jianmin Wang
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Min Zhao
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Xiaolei Duan
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.,Department of Laboratory Medicine, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000, Guizhou, China
| | - Liangsheng Kong
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Wei Cheng
- The Center for Clinical Molecular Medical detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Shijia Ding
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
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Papp-Wallace KM, Mack AR, Taracila MA, Bonomo RA. Resistance to Novel β-Lactam-β-Lactamase Inhibitor Combinations: The "Price of Progress". Infect Dis Clin North Am 2020; 34:773-819. [PMID: 33011051 DOI: 10.1016/j.idc.2020.05.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Significant advances were made in antibiotic development during the past 5 years. Novel agents were added to the arsenal that target critical priority pathogens, including multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacterales. Of these, 4 novel β-lactam-β-lactamase inhibitor combinations (ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-cilastatin-relebactam) reached clinical approval in the United States. With these additions comes a significant responsibility to reduce the possibility of emergence of resistance. Reports in the rise of resistance toward ceftolozane-tazobactam and ceftazidime-avibactam are alarming. Clinicians and scientists must make every attempt to reverse or halt these setbacks.
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Affiliation(s)
- Krisztina M Papp-Wallace
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, 151W, 10701 East Boulevard, Cleveland, OH 44106, USA.
| | - Andrew R Mack
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, 151W, 10701 East Boulevard, Cleveland, OH 44106, USA
| | - Magdalena A Taracila
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, 151W, 10701 East Boulevard, Cleveland, OH 44106, USA
| | - Robert A Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, 151W, 10701 East Boulevard, Cleveland, OH 44106, USA.
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DeMeester KE, Liang H, Zhou J, Wodzanowski KA, Prather BL, Santiago CC, Grimes CL. Metabolic Incorporation of N-Acetyl Muramic Acid Probes into Bacterial Peptidoglycan. ACTA ACUST UNITED AC 2020; 11:e74. [PMID: 31763799 DOI: 10.1002/cpch.74] [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] [Indexed: 12/29/2022]
Abstract
Bacterial cells utilize small carbohydrate building blocks to construct peptidoglycan (PG), a highly conserved mesh-like polymer that serves as a protective coat for the cell. PG production has long been a target for antibiotics, and its breakdown is a source for human immune recognition. A key component of bacterial PG, N-acetyl muramic acid (NAM), is a vital element in many synthetically derived immunostimulatory compounds. However, the exact molecular details of these structures and how they are generated remain unknown due to a lack of chemical probes surrounding the NAM core. A robust synthetic strategy to generate bioorthogonally tagged NAM carbohydrate units is implemented. These molecules serve as precursors for PG biosynthesis and recycling. Escherichia coli cells are metabolically engineered to incorporate the bioorthogonal NAM probes into their PG network. The probes are subsequently modified using copper-catalyzed azide-alkyne cycloaddition to install fluorophores directly into the bacterial PG, as confirmed by super-resolution microscopy and high-resolution mass spectrometry. Here, synthetic notes for key elements of this process to generate the sugar probes as well as streamlined user-friendly metabolic labeling strategies for both microbiology and immunological applications are described. © 2019 by John Wiley & Sons, Inc. Basic Protocol 1: Synthesis of peracetylated 2-azido glucosamine Basic Protocol 2: Synthesis of 2-azido and 2-alkyne NAM Basic Protocol 3: Synthesis of 3-azido NAM methyl ester Basic Protocol 4: Incorporation of NAM probes into bacterial peptidoglycan Basic Protocol 5: Confirmation of bacterial cell wall remodeling by mass spectrometry.
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Affiliation(s)
- Kristen E DeMeester
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware
| | - Hai Liang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware.,Cutaneous Microbiome and Inflammation Section, Dermatology Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, Maryland
| | - Junhui Zhou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware
| | | | - Benjamin L Prather
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware
| | - Cintia C Santiago
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware.,Center for the Study of Organic Compounds, CEDECOR-UNLP-CIC, Department of Chemistry, Faculty of Exact Sciences, National University of La Plata, Buenos Aires, Argentina
| | - Catherine L Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware.,Department of Biological Sciences, University of Delaware, Newark, Delaware
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Maitra A, Munshi T, Healy J, Martin LT, Vollmer W, Keep NH, Bhakta S. Cell wall peptidoglycan in Mycobacterium tuberculosis: An Achilles' heel for the TB-causing pathogen. FEMS Microbiol Rev 2020; 43:548-575. [PMID: 31183501 PMCID: PMC6736417 DOI: 10.1093/femsre/fuz016] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/07/2019] [Indexed: 02/06/2023] Open
Abstract
Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis, remains one of the leading causes of mortality across the world. There is an urgent requirement to build a robust arsenal of effective antimicrobials, targeting novel molecular mechanisms to overcome the challenges posed by the increase of antibiotic resistance in TB. Mycobacterium tuberculosis has a unique cell envelope structure and composition, containing a peptidoglycan layer that is essential for maintaining cellular integrity and for virulence. The enzymes involved in the biosynthesis, degradation, remodelling and recycling of peptidoglycan have resurfaced as attractive targets for anti-infective drug discovery. Here, we review the importance of peptidoglycan, including the structure, function and regulation of key enzymes involved in its metabolism. We also discuss known inhibitors of ATP-dependent Mur ligases, and discuss the potential for the development of pan-enzyme inhibitors targeting multiple Mur ligases.
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Affiliation(s)
- Arundhati Maitra
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Tulika Munshi
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Jess Healy
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Liam T Martin
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK
| | - Nicholas H Keep
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Sanjib Bhakta
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
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Mourits VP, Koeken VACM, de Bree LCJ, Moorlag SJCFM, Chu WC, Xu X, Dijkstra H, Lemmers H, Joosten LAB, Wang Y, van Crevel R, Netea MG. BCG-Induced Trained Immunity in Healthy Individuals: The Effect of Plasma Muramyl Dipeptide Concentrations. J Immunol Res 2020; 2020:5812743. [PMID: 32626788 PMCID: PMC7312554 DOI: 10.1155/2020/5812743] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/20/2020] [Accepted: 05/19/2020] [Indexed: 01/01/2023] Open
Abstract
BCG vaccination protects not only against tuberculosis but also against heterologous infections. This effect differs between individuals, yet the factors responsible for this variation are unknown. BCG-induced nonspecific protection is, at least partially, mediated by innate immune reprogramming (trained immunity), which can be induced by the muramyl dipeptide (MDP) component of peptidoglycans. We aimed to study whether differential release of MDP in healthy individuals may explain variability of their response to BCG vaccination. Circulating MDP concentrations were increased up to three months after BCG vaccination. MDP concentrations at baseline, but not their increase postvaccination, positively correlated with the induction of trained immunity and not with mycobacteria-induced T-cell responses. Interestingly, MDP concentrations correlated with inflammatory markers in the circulation. In conclusion, circulating MDP concentrations are associated with the strength of trained immunity responses and thus influence the biological effects of BCG vaccination. This study increases our understanding about the role of MDP in BCG-induced trained immunity, which might help to optimize vaccine efficacy and explore novel applications of BCG vaccination.
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Affiliation(s)
- Vera P. Mourits
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Valerie A. C. M. Koeken
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - L. Charlotte J. de Bree
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
- Research Center for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut, 2300 Copenhagen, Denmark
- Odense Patient Data Explorative Network, University of Southern Denmark/Odense University Hospital, 5000 Odense, Denmark
| | - Simone J. C. F. M. Moorlag
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Wern Cui Chu
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Queenstown, Singapore 138673
| | - Xiaoli Xu
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Queenstown, Singapore 138673
| | - Helga Dijkstra
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Heidi Lemmers
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Leo A. B. Joosten
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
- Department of Medical Genetics, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Queenstown, Singapore 138673
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Queenstown, Singapore 119228
| | - Reinout van Crevel
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Mihai G. Netea
- Department of Internal Medicine, Radboud Institute of Molecular Life Sciences (RIMLS) and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, 6525 Nijmegen, Netherlands
- Department for Genomics & Immunoregulation, Life and Medical Sciences Institute (LIMES), University of Bonn, 53115 Bonn, Germany
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Dik DA, Kim C, Madukoma CS, Fisher JF, Shrout JD, Mobashery S. Fluorescence Assessment of the AmpR-Signaling Network of Pseudomonas aeruginosa to Exposure to β-Lactam Antibiotics. ACS Chem Biol 2020; 15:1184-1194. [PMID: 31990176 DOI: 10.1021/acschembio.9b00875] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gram-negative bacteria have evolved an elaborate pathway to sense and respond to exposure to β-lactam antibiotics. The β-lactam antibiotics inhibit penicillin-binding proteins, whereby the loss of their activities alters/damages the cell-wall peptidoglycan. Bacteria sense this damage and remove the affected peptidoglycan into complex recycling pathways. As an offshoot of these pathways, muropeptide chemical signals generated from the cell-wall recycling manifest the production of a class C β-lactamase, which hydrolytically degrades the β-lactam antibiotic as a resistance mechanism. We disclose the use of a fluorescence probe that detects the activation of the recycling system by the formation of the key muropeptides involved in signaling. This same probe additionally detects natural-product cell-wall-active antibiotics that are produced in situ by cohabitating bacteria.
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Affiliation(s)
- David A. Dik
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Choon Kim
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Chinedu S. Madukoma
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jed F. Fisher
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Joshua D. Shrout
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Shaku M, Ealand C, Matlhabe O, Lala R, Kana BD. Peptidoglycan biosynthesis and remodeling revisited. ADVANCES IN APPLIED MICROBIOLOGY 2020; 112:67-103. [PMID: 32762868 DOI: 10.1016/bs.aambs.2020.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The bacterial peptidoglycan layer forms a complex mesh-like structure that surrounds the cell, imparting rigidity to withstand cytoplasmic turgor and the ability to tolerate stress. As peptidoglycan has been the target of numerous clinically successful antimicrobials such as penicillin, the biosynthesis, remodeling and recycling of this polymer has been the subject of much interest. Herein, we review recent advances in the understanding of peptidoglycan biosynthesis and remodeling in a variety of different organisms. In order for bacterial cells to grow and divide, remodeling of cross-linked peptidoglycan is essential hence, we also summarize the activity of important peptidoglycan hydrolases and how their functions differ in various species. There is a growing body of evidence highlighting complex regulatory mechanisms for peptidoglycan metabolism including protein interactions, phosphorylation and protein degradation and we summarize key recent findings in this regard. Finally, we provide an overview of peptidoglycan recycling and how components of this pathway mediate resistance to drugs. In the face of growing antimicrobial resistance, these recent advances are expected to uncover new drug targets in peptidoglycan metabolism, which can be used to develop novel therapies.
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Affiliation(s)
- Moagi Shaku
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Christopher Ealand
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Ofentse Matlhabe
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Rushil Lala
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Bavesh D Kana
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa.
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Abstract
The FtsZ protein is a highly conserved bacterial tubulin homolog. In vivo, the functional form of FtsZ is the polymeric, ring-like structure (Z-ring) assembled at the future division site during cell division. While it is clear that the Z-ring plays an essential role in orchestrating cytokinesis, precisely what its functions are and how these functions are achieved remain elusive. In this article, we review what we have learned during the past decade about the Z-ring's structure, function, and dynamics, with a particular focus on insights generated by recent high-resolution imaging and single-molecule analyses. We suggest that the major function of the Z-ring is to govern nascent cell pole morphogenesis by directing the spatiotemporal distribution of septal cell wall remodeling enzymes through the Z-ring's GTP hydrolysis-dependent treadmilling dynamics. In this role, FtsZ functions in cell division as the counterpart of the cell shape-determining actin homolog MreB in cell elongation.
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Affiliation(s)
- Ryan McQuillen
- Department of Biophysics & Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; ,
| | - Jie Xiao
- Department of Biophysics & Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; ,
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Chlamydia trachomatis Oligopeptide Transporter Performs Dual Functions of Oligopeptide Transport and Peptidoglycan Recycling. Infect Immun 2020; 88:IAI.00086-20. [PMID: 32094256 DOI: 10.1128/iai.00086-20] [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: 02/14/2020] [Accepted: 02/18/2020] [Indexed: 12/20/2022] Open
Abstract
Peptidoglycan, the sugar-amino acid polymer that composes the bacterial cell wall, requires a significant expenditure of energy to synthesize and is highly immunogenic. To minimize the loss of an energetically expensive metabolite and avoid host detection, bacteria often recycle their peptidoglycan, transporting its components back into the cytoplasm, where they can be used for subsequent rounds of new synthesis. The peptidoglycan-recycling substrate binding protein (SBP) MppA, which is responsible for recycling peptidoglycan fragments in Escherichia coli, has not been annotated for most intracellular pathogens. One such pathogen, Chlamydia trachomatis, has a limited capacity to synthesize amino acids de novo and therefore must obtain oligopeptides from its host cell for growth. Bioinformatics analysis suggests that the putative C. trachomatis oligopeptide transporter OppABCDF (OppABCDF Ct ) encodes multiple SBPs (OppA1 Ct , OppA2 Ct , and OppA3 Ct ). Intracellular pathogens often encode multiple SBPs, while only one, OppA, is encoded in the E. coli opp operon. We hypothesized that the putative OppABCDF transporter of C. trachomatis functions in both oligopeptide transport and peptidoglycan recycling. We coexpressed the putative SBP genes (oppA1Ct , oppA2Ct , oppA3Ct ) along with oppBCDFCt in an E. coli mutant lacking the Opp transporter and determined that all three chlamydial OppA subunits supported oligopeptide transport. We also demonstrated the in vivo functionality of the chlamydial Opp transporter in C. trachomatis Importantly, we found that one chlamydial SBP, OppA3 Ct , possessed dual substrate recognition properties and is capable of transporting peptidoglycan fragments (tri-diaminopimelic acid) in E. coli and in C. trachomatis These findings suggest that Chlamydia evolved an oligopeptide transporter to facilitate the acquisition of oligopeptides for growth while simultaneously reducing the accumulation of immunostimulatory peptidoglycan fragments in the host cell cytosol. The latter property reflects bacterial pathoadaptation that dampens the host innate immune response to Chlamydia infection.
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d-Methionine and d-Phenylalanine Improve Lactococcus lactis F44 Acid Resistance and Nisin Yield by Governing Cell Wall Remodeling. Appl Environ Microbiol 2020; 86:AEM.02981-19. [PMID: 32111594 DOI: 10.1128/aem.02981-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 02/22/2020] [Indexed: 12/30/2022] Open
Abstract
Lactococcus lactis encounters various environmental challenges, especially acid stress, during its growth. The cell wall can maintain the integrity and shape of the cell under environmental stress, and d-amino acids play an important role in cell wall synthesis. Here, by analyzing the effects of 19 different d-amino acids on the physiology of L. lactis F44, we found that exogenously supplied d-methionine and d-phenylalanine increased the nisin yield by 93.22% and 101.29%, respectively, as well as significantly increasing the acid resistance of L. lactis F44. The composition of the cell wall in L. lactis F44 with exogenously supplied d-Met or d-Phe was further investigated via a vancomycin fluorescence experiment and a liquid chromatography-mass spectrometry assay, which demonstrated that d-Met could be incorporated into the fifth position of peptidoglycan (PG) muropeptides and d-Phe could be added to the fourth and fifth positions. Moreover, overexpression of the PG synthesis gene murF further enhanced the levels of d-Met and d-Phe involved in PG and increased the survival rate under acid stress and the nisin yield of the strain. This study reveals that the exogenous supply of d-Met or d-Phe can change the composition of the cell wall and influence acid tolerance as well as nisin yield in L. lactis IMPORTANCE As d-amino acids play an important role in cell wall synthesis, we analyzed the effects of 19 different d-amino acids on L. lactis F44, demonstrating that d-Met and d-Phe can participate in peptidoglycan (PG) synthesis and improve the acid resistance and nisin yield of this strain. murF overexpression further increased the levels of d-Met and d-Phe incorporated into PG and contributed to the acid resistance of the strain. These findings suggest that d-Met and d-Phe can be incorporated into PG to improve the acid resistance and nisin yield of L. lactis, and this study provides new ideas for the enhancement of nisin production.
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Ukaegbu OI, DeMeester KE, Liang H, Brown AR, Jones ZS, Grimes CL. Utility of bacterial peptidoglycan recycling enzymes in the chemoenzymatic synthesis of valuable UDP sugar substrates. Methods Enzymol 2020; 638:1-26. [PMID: 32416908 DOI: 10.1016/bs.mie.2020.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Uridine diphosphate (UDP) sugars are essential precursors for glycosylation reactions in all forms of life. Reactions that transfer the carbohydrate from the UDP donor are catalyzed by glycosyltransferases (Gtfs). While the stereochemistry and negative physiological charge of UDP-sugars are essential for their biochemical function in the cell, these characteristics make them challenging molecules to synthesize and purify on scale in the laboratory. This chapter focuses on the utilization of a chemoenzymatic synthesis of muramyl UDP-sugars, key building blocks in the bacterial cell peptidoglycan. A scalable strategy to obtain UDP-N-acetyl muramic acid derivatives (UDP-NAM), the first committed intermediate used solely in peptidoglycan biosynthesis, is described herein. This methodology utilizes two enzymes involving the cell wall recycling enzymes MurNAc/GlcNAc anomeric kinase (AmgK) and NAM α-1-phosphate uridylyl transferase (MurU), respectively. The promiscuity of these enzymes allows for the unique chemical functionality to be embedded in bacterial peptidoglycan both in vitro and in whole bacterial cells for subsequent structural and functional studies of this important biopolymer.
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Affiliation(s)
- Ophelia I Ukaegbu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States
| | - Kristen E DeMeester
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States
| | - Hai Liang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States
| | - Ashley R Brown
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States
| | - Zachary S Jones
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States
| | - Catherine Leimkuhler Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States; Department of Biological Sciences, University of Delaware, Newark, DE, United States.
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Böhm ME, Razavi M, Marathe NP, Flach CF, Larsson DGJ. Discovery of a novel integron-borne aminoglycoside resistance gene present in clinical pathogens by screening environmental bacterial communities. MICROBIOME 2020; 8:41. [PMID: 32197644 PMCID: PMC7085159 DOI: 10.1186/s40168-020-00814-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/02/2020] [Indexed: 05/12/2023]
Abstract
BACKGROUND New antibiotic resistance determinants are generally discovered too late, long after they have irreversibly emerged in pathogens and spread widely. Early discovery of resistance genes, before or soon after their transfer to pathogens could allow more effective measures to monitor and reduce spread, and facilitate genetics-based diagnostics. RESULTS We modified a functional metagenomics approach followed by in silico filtering of known resistance genes to discover novel, mobilised resistance genes in class 1 integrons in wastewater-impacted environments. We identified an integron-borne gene cassette encoding a protein that conveys high-level resistance against aminoglycosides with a garosamine moiety when expressed in E. coli. The gene is named gar (garosamine-specific aminoglycoside resistance) after its specificity. It contains none of the functional domains of known aminoglycoside modifying enzymes, but bears characteristics of a kinase. By searching public databases, we found that the gene occurs in three sequenced, multi-resistant clinical isolates (two Pseudomonas aeruginosa and one Luteimonas sp.) from Italy and China, respectively, as well as in two food-borne Salmonella enterica isolates from the USA. In all cases, gar has escaped discovery until now. CONCLUSION To the best of our knowledge, this is the first time a novel resistance gene, present in clinical isolates, has been discovered by exploring the environmental microbiome. The gar gene has spread horizontally to different species on at least three continents, further limiting treatment options for bacterial infections. Its specificity to garosamine-containing aminoglycosides may reduce the usefulness of the newest semisynthetic aminoglycoside plazomicin, which is designed to avoid common aminoglycoside resistance mechanisms. Since the gene appears to be not yet common in the clinics, the data presented here enables early surveillance and maybe even mitigation of its spread.
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Affiliation(s)
- Maria-Elisabeth Böhm
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mohammad Razavi
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Nachiket P. Marathe
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Institute of Marine Research (IMR), Bergen, Norway
| | - Carl-Fredrik Flach
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - D. G. Joakim Larsson
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Abushaheen MA, Muzaheed, Fatani AJ, Alosaimi M, Mansy W, George M, Acharya S, Rathod S, Divakar DD, Jhugroo C, Vellappally S, Khan AA, Shaik J, Jhugroo P. Antimicrobial resistance, mechanisms and its clinical significance. Dis Mon 2020; 66:100971. [PMID: 32201008 DOI: 10.1016/j.disamonth.2020.100971] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Antimicrobial agents play a key role in controlling and curing infectious disease. Soon after the discovery of the first antibiotic, the challenge of antibiotic resistance commenced. Antimicrobial agents use different mechanisms against bacteria to prevent their pathogenesis and they can be classified as bactericidal or bacteriostatic. Antibiotics are one of the antimicrobial agents which has several classes, each with different targets. Consequently, bacteria are endlessly using methods to overcome the effectivity of the antibiotics by using distinct types of mechanisms. Comprehending the mechanisms of resistance is vital for better understanding and to continue use of current antibiotics. Which also helps to formulate synthetic antimicrobials to overcome the current mechanism of resistance. Also, encourage in prudent use and misuse of antimicrobial agents. Thus, decline in treatment costs and in the rate of morbidity and mortality. This review will be concentrating on the mechanism of actions of several antibiotics and how bacteria develop resistance to them, as well as the method of acquiring the resistance in several bacteria and how can a strain be resistant to several types of antibiotics. This review also analyzes the prevalence, major clinical implications, clinical causes of antibiotic resistance. Further, it evaluates the global burden of antimicrobial resistance, identifies various challenges and strategies in addressing the issue. Finally, put forward certain recommendations to prevent the spread and reduce the rate of resistance growth.
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Affiliation(s)
- Manar Ali Abushaheen
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Muzaheed
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia.
| | - Amal Jamil Fatani
- Department of Pharmacology & Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed Alosaimi
- Consultant, Department of Restorative Dentistry, College of Dentistry, King Saud bin Abdul Aziz University for Health Sciences, P.O Box: 22490, Riyadh 11426, Saudi Arabia
| | - Wael Mansy
- Clinical Pharmacy Department, College of Pharmacy, King Saud University, Saudi Arabia; Pharmacology Department, Faculty of Medicine, Cairo University, Egypt
| | - Merin George
- General Dentist and Public Health Researcher, Australia
| | - Sadananda Acharya
- Department of Public Health, College of Public Health, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Sanjay Rathod
- Department of Post Graduate Studies and Research in Microbiology, Gulbarga University, Gulbarga- 585106, India
| | - Darshan Devang Divakar
- Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Chitra Jhugroo
- Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Sajith Vellappally
- Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Aftab Ahmed Khan
- Dental Biomaterials Research Chair, Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
| | - Jilani Shaik
- Genome Research Chair, Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Poojdev Jhugroo
- CAP Research Ltd., 2nd Floor Orbis Court, 132 St Jean Road 72218 Quatre Bornes, Mauritius
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Böhm ME, Razavi M, Flach CF, Larsson DGJ. A Novel, Integron-Regulated, Class C β-Lactamase. Antibiotics (Basel) 2020; 9:antibiotics9030123. [PMID: 32183280 PMCID: PMC7148499 DOI: 10.3390/antibiotics9030123] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/26/2022] Open
Abstract
AmpC-type β-lactamases severely impair treatment of many bacterial infections, due to their broad spectrum (they hydrolyze virtually all β-lactams, except fourth-generation cephalosporins and carbapenems) and the increasing incidence of plasmid-mediated versions. The original chromosomal AmpCs are often tightly regulated, and their expression is induced in response to exposure to β-lactams. Regulation of mobile ampC expression is in many cases less controlled, giving rise to constitutively resistant strains with increased potential for development or acquisition of additional resistances. We present here the identification of two integron-encoded ampC genes, blaIDC-1 and blaIDC-2 (integron-derived cephalosporinase), with less than 85% amino acid sequence identity to any previously annotated AmpC. While their resistance pattern identifies them as class C β-lactamases, their low isoelectric point (pI) values make differentiation from other β-lactamases by isoelectric focusing impossible. To the best of our knowledge, this is the first evidence of an ampC gene cassette within a class 1 integron, providing a mobile context with profound potential for transfer and spread into clinics. It also allows bacteria to adapt expression levels, and thus reduce fitness costs, e.g., by cassette-reshuffling. Analyses of public metagenomes, including sewage metagenomes, show that the discovered ampCs are primarily found in Asian countries.
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Affiliation(s)
- Maria-Elisabeth Böhm
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Mohammad Razavi
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Carl-Fredrik Flach
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - D. G. Joakim Larsson
- Centre for Antibiotic Resistance Research (CARe), University of Gothenburg, Gothenburg, Sweden; (M.-E.B.); (M.R.); (C.-F.F.)
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
- Correspondence:
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73
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Fisher JF, Mobashery S. Constructing and deconstructing the bacterial cell wall. Protein Sci 2020; 29:629-646. [PMID: 31747090 PMCID: PMC7021008 DOI: 10.1002/pro.3737] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 12/11/2022]
Abstract
The history of modern medicine cannot be written apart from the history of the antibiotics. Antibiotics are cytotoxic secondary metabolites that are isolated from Nature. The antibacterial antibiotics disproportionately target bacterial protein structure that is distinct from eukaryotic protein structure, notably within the ribosome and within the pathways for bacterial cell-wall biosynthesis (for which there is not a eukaryotic counterpart). This review focuses on a pre-eminent class of antibiotics-the β-lactams, exemplified by the penicillins and cephalosporins-from the perspective of the evolving mechanisms for bacterial resistance. The mechanism of action of the β-lactams is bacterial cell-wall destruction. In the monoderm (single membrane, Gram-positive staining) pathogen Staphylococcus aureus the dominant resistance mechanism is expression of a β-lactam-unreactive transpeptidase enzyme that functions in cell-wall construction. In the diderm (dual membrane, Gram-negative staining) pathogen Pseudomonas aeruginosa a dominant resistance mechanism (among several) is expression of a hydrolytic enzyme that destroys the critical β-lactam ring of the antibiotic. The key sensing mechanism used by P. aeruginosa is monitoring the molecular difference between cell-wall construction and cell-wall deconstruction. In both bacteria, the resistance pathways are manifested only when the bacteria detect the presence of β-lactams. This review summarizes how the β-lactams are sensed and how the resistance mechanisms are manifested, with the expectation that preventing these processes will be critical to future chemotherapeutic control of multidrug resistant bacteria.
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Affiliation(s)
- Jed F. Fisher
- Department of Chemistry and BiochemistryUniversity of Notre DameSouth BendIndiana
| | - Shahriar Mobashery
- Department of Chemistry and BiochemistryUniversity of Notre DameSouth BendIndiana
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74
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Yu W, Li D, Li H, Tang Y, Tang H, Ma X, Liu Z. Absence of tmRNA Increases the Persistence to Cefotaxime and the Intercellular Accumulation of Metabolite GlcNAc in Aeromonas veronii. Front Cell Infect Microbiol 2020; 10:44. [PMID: 32185140 PMCID: PMC7058587 DOI: 10.3389/fcimb.2020.00044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/23/2020] [Indexed: 12/27/2022] Open
Abstract
Bacterial persisters are a small proportion of phenotypically heterogeneous variants with the transient capability to survive in high concentrations of antibiotics, causing recurrent infections in both human and aquatic animals. Transfer-messenger RNA (tmRNA), which was encoded by the ssrA gene, was identified as a determinant regulator mediating the persistence to β-lactams in the pathogenic Aeromonas veronii C4. The deletion of tmRNA exhibited the increased ability of persister formation most probably due to the reduction of protein synthesis. Transcriptomic and metabolomic analyses revealed that the absence of tmRNA not only significantly elevated the intercellular levels of metabolite GlcNAc and promoted NaCl osmotic tolerance, but also upregulated the expression of metabolic genes in both the upstream biosynthesis pathway and the downstream metabolic flux of peptidoglycan (PG) biosynthesis. Finally, exogenous GlcNAc stimulated significant bacterial growth, enhanced content of GlcNAc in the cell wall, higher resistance to osmotic response, and higher persistence to cefotaxime in a concentration-dependent manner, implying its potential role in promoting the multiple phenotypes observed in tmRNA deletion strains. Taken together, these results hint at a potential mechanism of persister formation mediated by tmRNA against the β-lactam challenges in A. veronii.
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Affiliation(s)
- Wenjing Yu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China.,School of Tropical Crops, Hainan University, Haikou, China
| | - Daiyu Li
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Hong Li
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Yanqiong Tang
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Hongqian Tang
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Xiang Ma
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Zhu Liu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou, China
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75
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Characterization and diversity of the complete set of GH family 3 enzymes from Rhodothermus marinus DSM 4253. Sci Rep 2020; 10:1329. [PMID: 31992772 PMCID: PMC6987092 DOI: 10.1038/s41598-020-58015-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/07/2020] [Indexed: 11/08/2022] Open
Abstract
The genome of Rhodothermus marinus DSM 4253 encodes six glycoside hydrolases (GH) classified under GH family 3 (GH3): RmBgl3A, RmBgl3B, RmBgl3C, RmXyl3A, RmXyl3B and RmNag3. The biochemical function, modelled 3D-structure, gene cluster and evolutionary relationships of each of these enzymes were studied. The six enzymes were clustered into three major evolutionary lineages of GH3: β-N-acetyl-glucosaminidases, β-1,4-glucosidases/β-xylosidases and macrolide β-glucosidases. The RmNag3 with additional β-lactamase domain clustered with the deepest rooted GH3-lineage of β-N-acetyl-glucosaminidases and was active on acetyl-chitooligosaccharides. RmBgl3B displayed β-1,4-glucosidase activity and was the only representative of the lineage clustered with macrolide β-glucosidases from Actinomycetes. The β-xylosidases, RmXyl3A and RmXyl3B, and the β-glucosidases RmBgl3A and RmBgl3C clustered within the major β-glucosidases/β-xylosidases evolutionary lineage. RmXyl3A and RmXyl3B showed β-xylosidase activity with different specificities for para-nitrophenyl (pNP)-linked substrates and xylooligosaccharides. RmBgl3A displayed β-1,4-glucosidase/β-xylosidase activity while RmBgl3C was active on pNP-β-Glc and β-1,3-1,4-linked glucosyl disaccharides. Putative polysaccharide utilization gene clusters were also investigated for both R. marinus DSM 4253 and DSM 4252T (homolog strain). The analysis showed that in the homolog strain DSM 4252TRmar_1080 (RmXyl3A) and Rmar_1081 (RmXyl3B) are parts of a putative polysaccharide utilization locus (PUL) for xylan utilization.
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76
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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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77
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Sais M, Barroeta AC, López-Colom P, Nofrarías M, Majó N, Lopez-Ulibarri R, Pérez Calvo E, Martín-Orúe SM. Evaluation of dietary supplementation of a novel microbial muramidase on gastrointestinal functionality and growth performance in broiler chickens. Poult Sci 2020; 99:235-245. [PMID: 32416807 PMCID: PMC7587705 DOI: 10.3382/ps/pez466] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 08/05/2019] [Indexed: 12/17/2022] Open
Abstract
This study was conducted to assess the effect of dietary supplementation of Muramidase 007 to broiler chickens on gastrointestinal functionality, evaluating growth performance, apparent ileal digestibility, intestinal histomorphology, vitamin A in plasma and cecal microbiota. A total of 480 one-day male chicks (Ross 308) were distributed in 16 pens allocated in 2 experimental diets: the control diet (CTR) without feed enzymes, coccidiostat or growth promoters, and the experimental diet (MUR): CTR supplemented with 35,000 units (LSU(F))/kg of the Muramidase 007. Digesta and tissue samples were obtained on days 9 and 36 of the study. A lower feed conversion ratio was observed in the MUR treatment. Apparent ileal digestibility of DM, organic matter and energy were improved by Muramidase 007. It was also observed that MUR improved digestibility of total fatty acids, mono-unsaturated fatty acids and poly-unsaturated fatty acids, and content of vitamin A in plasma at day 9 (P < 0.05). Histomorphological analysis of jejunum samples revealed no differences in the villus height or crypt depth; but a higher number of goblet cells and intraepithelial lymphocytes at day 36 with MUR. No differences were observed in plate counts of enterobacteria or Lactobacillus along the gastrointestinal tract, neither on the cecal short-chain fatty acids. An statistical trend was observed for reduction of cecal clostridia at day 9 for MUR. Analysis of cecal microbiota structure by 16S rRNA gene sequencing revealed relevant changes correlated to age. At day 9, broilers receiving MUR showed decreased alpha diversity compared to CTR that was not detected at day 36. Changes in specific taxonomic groups with an increase in Lactobacillus genus were identified. In conclusion, evaluation of the variables in this study indicates that dietary Muramidase 007 contributes to improve feed conversation ratio and gastrointestinal function in broiler chickens. Effects could have been mediated by slight shifts observed in the intestinal microbiota. More studies are guaranteed to fully understand the mechanisms involved.
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Affiliation(s)
- Mounira Sais
- Animal Nutrition and Welfare Service. Animal and Food Science Department, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Ana C Barroeta
- Animal Nutrition and Welfare Service. Animal and Food Science Department, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Paola López-Colom
- Animal Nutrition and Welfare Service. Animal and Food Science Department, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Miquel Nofrarías
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, UAB-IRTA), Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Natàlia Majó
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, UAB-IRTA), Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain; Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Rual Lopez-Ulibarri
- DSM Nutritional Products Ltd, Nutrition Innovation Center - ANH, 4303 Kaiseraugst, Switzerland
| | - Estefanía Pérez Calvo
- DSM Nutritional Products Ltd, Nutrition Innovation Center - ANH, 68128 Village Neuf, France
| | - Susana M Martín-Orúe
- Animal Nutrition and Welfare Service. Animal and Food Science Department, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain.
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Anderson EM, Sychantha D, Brewer D, Clarke AJ, Geddes-McAlister J, Khursigara CM. Peptidoglycomics reveals compositional changes in peptidoglycan between biofilm- and planktonic-derived Pseudomonas aeruginosa. J Biol Chem 2019; 295:504-516. [PMID: 31771981 DOI: 10.1074/jbc.ra119.010505] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/25/2019] [Indexed: 12/14/2022] Open
Abstract
Peptidoglycan (PG) is a critical component of the bacterial cell wall and is composed of a repeating β-1,4-linked disaccharide of N-acetylglucosamine and N-acetylmuramic acid appended with a highly conserved stem peptide. In Gram-negative bacteria, PG is assembled in the cytoplasm and exported into the periplasm where it undergoes considerable maturation, modification, or degradation depending on the growth phase or presence of environmental stressors. These modifications serve important functions in diverse processes, including PG turnover, cell elongation/division, and antibiotic resistance. Conventional methods for analyzing PG composition are complex and time-consuming. We present here a streamlined MS-based method that combines differential analysis with statistical 1D annotation approaches to quantitatively compare PGs produced in planktonic- and biofilm-cultured Pseudomonas aeruginosa We identified a core assembly of PG that is present in high abundance and that does not significantly differ between the two growth states. We also identified an adaptive PG assembly that is present in smaller amounts and fluctuates considerably between growth states in response to physiological changes. Biofilm-derived adaptive PG exhibited significant changes compared with planktonic-derived PG, including amino acid substitutions of the stem peptide and modifications that indicate changes in the activity of amidases, deacetylases, and lytic transglycosylases. The results of this work also provide first evidence of de-N-acetylated muropeptides from P. aeruginosa The method developed here offers a robust and reproducible workflow for accurately determining PG composition in samples that can be used to assess global PG fluctuations in response to changing growth conditions or external stimuli.
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Affiliation(s)
- Erin M Anderson
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - David Sychantha
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - Dyanne Brewer
- Mass Spectrometry Facility, University of Guelph, Ontario N1G 2W1, Canada
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - Jennifer Geddes-McAlister
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada; Mass Spectrometry Facility, University of Guelph, Ontario N1G 2W1, Canada.
| | - Cezar M Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada; Mass Spectrometry Facility, University of Guelph, Ontario N1G 2W1, Canada.
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79
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Roles of lytic transglycosylases in biofilm formation and β-lactam resistance in methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 2019:AAC.01277-19. [PMID: 31570396 DOI: 10.1128/aac.01277-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is responsible for numerous community outbreaks and is one of the most frequent causes of nosocomial infections with significant morbidity and mortality. While the function of lytic transglycosylases (LTs) in relation to cell division, biofilm formation, and antibiotic resistance has been determined for several bacteria, their role in S. aureus remains largely unknown. The only known LTs in S. aureus are immunodominant staphylococcal antigen A (IsaA) and Staphylococcus epidermidis D protein (SceD). Our study demonstrates that, in a strain of methicillin-resistant S. aureus (MRSA), IsaA and SceD contribute differently to biofilm formation and β-lactam resistance. Deletion of isaA, but not sceD, led to decreased biofilm formation. Additionally, in isaA-deleted strains, β-lactam resistance was significantly decreased compared to that of wild-type strains. Plasmid-based expression of mecA, a major determinant of β-lactam resistance in MRSA, in an isaA-deleted strain did not restore β-lactam resistance, demonstrating that the β-lactam susceptibility phenotype is exhibited by isaA mutant regardless of the production level of PBP2a. Overall, our results suggest that IsaA is a potential therapeutic target for MRSA infections.
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80
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Capo F, Wilson A, Di Cara F. The Intestine of Drosophila melanogaster: An Emerging Versatile Model System to Study Intestinal Epithelial Homeostasis and Host-Microbial Interactions in Humans. Microorganisms 2019; 7:microorganisms7090336. [PMID: 31505811 PMCID: PMC6780840 DOI: 10.3390/microorganisms7090336] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/16/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022] Open
Abstract
In all metazoans, the intestinal tract is an essential organ to integrate nutritional signaling, hormonal cues and immunometabolic networks. The dysregulation of intestinal epithelium functions can impact organism physiology and, in humans, leads to devastating and complex diseases, such as inflammatory bowel diseases, intestinal cancers, and obesity. Two decades ago, the discovery of an immune response in the intestine of the genetic model system, Drosophila melanogaster, sparked interest in using this model organism to dissect the mechanisms that govern gut (patho) physiology in humans. In 2007, the finding of the intestinal stem cell lineage, followed by the development of tools available for its manipulation in vivo, helped to elucidate the structural organization and functions of the fly intestine and its similarity with mammalian gastrointestinal systems. To date, studies of the Drosophila gut have already helped to shed light on a broad range of biological questions regarding stem cells and their niches, interorgan communication, immunity and immunometabolism, making the Drosophila a promising model organism for human enteric studies. This review summarizes our current knowledge of the structure and functions of the Drosophila melanogaster intestine, asserting its validity as an emerging model system to study gut physiology, regeneration, immune defenses and host-microbiota interactions.
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Affiliation(s)
- Florence Capo
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| | - Alexa Wilson
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| | - Francesca Di Cara
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
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81
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Dörr T, Moynihan PJ, Mayer C. Editorial: Bacterial Cell Wall Structure and Dynamics. Front Microbiol 2019; 10:2051. [PMID: 31551985 PMCID: PMC6737391 DOI: 10.3389/fmicb.2019.02051] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 08/20/2019] [Indexed: 12/23/2022] Open
Affiliation(s)
- Tobias Dörr
- Department of Microbiology, Weill Institute for Cell and Molecular Biology, Ithaca, NY, United States.,Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States
| | - Patrick J Moynihan
- School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Christoph Mayer
- Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
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82
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A New Suite of Allelic-Exchange Vectors for the Scarless Modification of Proteobacterial Genomes. Appl Environ Microbiol 2019; 85:AEM.00990-19. [PMID: 31201277 DOI: 10.1128/aem.00990-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 06/06/2019] [Indexed: 01/05/2023] Open
Abstract
Despite the advent of new techniques for genetic engineering of bacteria, allelic exchange through homologous recombination remains an important tool for genetic analysis. Currently, sacB-based vector systems are often used for allelic exchange, but counterselection escape, which prevents isolation of cells with the desired mutation, occasionally limits their utility. To circumvent this, we engineered a series of "pTOX" allelic-exchange vectors. Each plasmid encodes one of a set of inducible toxins, chosen for their potential utility in a wide range of medically important proteobacteria. A codon-optimized rhaS transcriptional activator with a strong synthetic ribosome-binding site enables tight toxin induction even in organisms lacking an endogenous rhamnose regulon. Expression of the gene encoding blue AmilCP or magenta TsPurple nonfluorescent chromoprotein facilitates monitoring of successful single- and double-crossover events using these vectors. The versatility of these vectors was demonstrated by deleting genes in Serratia marcescens, Escherichia coli O157:H7, Enterobacter cloacae, and Shigella flexneri Finally, pTOX was used to characterize the impact of disruption of all combinations of the 3 paralogous S. marcescens peptidoglycan amidohydrolases on chromosomal ampC β-lactamase activity and the corresponding β-lactam antibiotic resistance. Mutation of multiple amidohydrolases was necessary for high-level ampC derepression and β-lactam resistance. These data suggest why β-lactam resistance may emerge during treatment less frequently in S. marcescens than in other AmpC-producing pathogens, like E. cloacae Collectively, our findings suggest that the pTOX vectors should be broadly useful for genetic engineering of Gram-negative bacteria.IMPORTANCE Targeted modification of bacterial genomes is critical for genetic analysis of microorganisms. Allelic exchange is a technique that relies on homologous recombination to replace native loci with engineered sequences. However, current allelic-exchange vectors often enable only weak selection for successful homologous recombination. We developed a suite of new allelic-exchange vectors, pTOX, which were validated in several medically important proteobacteria. They encode visible nonfluorescent chromoproteins that enable easy identification of colonies bearing integrated vectors and permit stringent selection for the second step of homologous recombination. We demonstrate the utility of these vectors by using them to investigate the effect of inactivation of Serratia marcescens peptidoglycan amidohydrolases on β-lactam antibiotic resistance.
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The hydrolase LpqI primes mycobacterial peptidoglycan recycling. Nat Commun 2019; 10:2647. [PMID: 31201321 PMCID: PMC6572805 DOI: 10.1038/s41467-019-10586-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 05/14/2019] [Indexed: 12/26/2022] Open
Abstract
Growth and division by most bacteria requires remodelling and cleavage of their cell wall. A byproduct of this process is the generation of free peptidoglycan (PG) fragments known as muropeptides, which are recycled in many model organisms. Bacteria and hosts can harness the unique nature of muropeptides as a signal for cell wall damage and infection, respectively. Despite this critical role for muropeptides, it has long been thought that pathogenic mycobacteria such as Mycobacterium tuberculosis do not recycle their PG. Herein we show that M. tuberculosis and Mycobacterium bovis BCG are able to recycle components of their PG. We demonstrate that the core mycobacterial gene lpqI, encodes an authentic NagZ β-N-acetylglucosaminidase and that it is essential for PG-derived amino sugar recycling via an unusual pathway. Together these data provide a critical first step in understanding how mycobacteria recycle their peptidoglycan. Bacterial growth and division require remodelling of the cell wall, which generates free peptidoglycan fragments. Here, Moynihan et al. show that Mycobacterium tuberculosis can recycle components of their peptidoglycan, and characterise a crucial enzyme required for this process.
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84
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Bachert BA, Biryukov SS, Chua J, Rodriguez SA, Toothman RG, Cote CK, Klimko CP, Hunter M, Shoe JL, Williams JA, Kuehl KA, Biot FV, Bozue JA. A Francisella novicida Mutant, Lacking the Soluble Lytic Transglycosylase Slt, Exhibits Defects in Both Growth and Virulence. Front Microbiol 2019; 10:1343. [PMID: 31258523 PMCID: PMC6587636 DOI: 10.3389/fmicb.2019.01343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/29/2019] [Indexed: 01/28/2023] Open
Abstract
Francisella tularensis is the causative agent of tularemia and has gained recent interest as it poses a significant biothreat risk. F. novicida is commonly used as a laboratory surrogate for tularemia research due to genetic similarity and susceptibility of mice to infection. Currently, there is no FDA-approved tularemia vaccine, and identifying therapeutic targets remains a critical gap in strategies for combating this pathogen. Here, we investigate the soluble lytic transglycosylase or Slt in F. novicida, which belongs to a class of peptidoglycan-modifying enzymes known to be involved in cell division. We assess the role of Slt in biology and virulence of the organism as well as the vaccine potential of the slt mutant. We show that the F. novicida slt mutant has a significant growth defect in acidic pH conditions. Further microscopic analysis revealed significantly altered cell morphology compared to wild-type, including larger cell size, extensive membrane protrusions, and cell clumping and fusion, which was partially restored by growth in neutral pH or genetic complementation. Viability of the mutant was also significantly decreased during growth in acidic medium, but not at neutral pH. Furthermore, the slt mutant exhibited significant attenuation in a murine model of intranasal infection and virulence could be restored by genetic complementation. Moreover, we could protect mice using the slt mutant as a live vaccine strain against challenge with the parent strain; however, we were not able to protect against challenge with the fully virulent F. tularensis Schu S4 strain. These studies demonstrate a critical role for the Slt enzyme in maintaining proper cell division and morphology in acidic conditions, as well as replication and virulence in vivo. Our results suggest that although the current vaccination strategy with F. novicida slt mutant would not protect against Schu S4 challenges, the Slt enzyme could be an ideal target for future therapeutic development.
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Affiliation(s)
- Beth A Bachert
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Sergei S Biryukov
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Jennifer Chua
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Sabrina A Rodriguez
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Ronald G Toothman
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Christopher K Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Christopher P Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Melissa Hunter
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Jennifer L Shoe
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Janice A Williams
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Kathleen A Kuehl
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
| | - Fabrice V Biot
- Unité de Bactériologie/UMR_MD1, Département de Biologie des Agents Transmissibles, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Joel A Bozue
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD, United States
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85
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Boulanger M, Delvaux C, Quinton L, Joris B, De Pauw E, Far J. Bacillus licheniformispeptidoglycan characterization by CZE–MS: Assessment with the benchmark RP‐HPLC‐MS method. Electrophoresis 2019; 40:2672-2682. [DOI: 10.1002/elps.201900147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Madeleine Boulanger
- Center for Protein Engineering, InBioS Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Cédric Delvaux
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Bernard Joris
- Center for Protein Engineering, InBioS Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
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86
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A novel autolysin AtlA SS mediates bacterial cell separation during cell division and contributes to full virulence in Streptococcus suis. Vet Microbiol 2019; 234:92-100. [PMID: 31213278 DOI: 10.1016/j.vetmic.2019.05.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 05/23/2019] [Indexed: 12/19/2022]
Abstract
Streptococcus suis (SS) is a major pathogen in the swine industry, and also an important zoonotic agent for humans. The novel SS cell surface protein, AtlASS, comprising the special GW module and N-acetylmuramidases domain, was designated as a putative autolysin. Indeed, the atlASS deletion mutant almost completely lost its activity in Triton X-100 induced bacterial autolysis, while the wild-type and CΔatlASS strains showed significant decrease, to less than 20% of the initial OD600 values. Unexpectedly, both immunofluorescence and immunogold electron microscopy confirmed that AtlASS is mainly located in the cell division septum, suggesting autolytic activity in peptidoglycan hydrolysis may be required for cell separation, thus modulating and truncating bacterial chain length. The biofilm capacity of the AtlASS mutation was reduced ˜ 40%, as compared to the wild-type strain. The ΔatlASS strain also attenuated bacterial adherence in human brain microvessel endothelial cells (HBMECs). Furthermore, we confirmed that AtlASS has fibrinogen/fibronectin binding capacities. In mouse infection model, the AtlASS inactivation also significantly attenuated bacterial virulence and proliferation in vivo. In conclusion, these results indicate that AtlASS autolysin modulates bacterial chain length, and contributes to the full virulence of SS during infection.
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87
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Abstract
The chapter about the Gram-positive bacterial cell wall gives a brief historical background on the discovery of Gram-positive cell walls and their constituents and microscopic methods applied for studying the Gram-positive cell envelope. Followed by the description of the different chemical building blocks of peptidoglycan and the biosynthesis of the peptidoglycan layers and high turnover of peptidoglycan during bacterial growth. Lipoteichoic acids and wall teichoic acids are highlighted as major components of the cell wall. Characterization of capsules and the formation of extracellular vesicles by Gram-positive bacteria close the section on cell envelopes which have a high impact on bacterial pathogenesis. In addition, the specialized complex and unusual cell wall of mycobacteria is introduced thereafter. Next a short back view is given on the development of electron microscopic examinations for studying bacterial cell walls. Different electron microscopic techniques and methods applied to examine bacterial cell envelopes are discussed in the view that most of the illustrated methods should be available in a well-equipped life sciences orientated electron microscopic laboratory. In addition, newly developed and mostly well-established cryo-methods like high-pressure freezing and freeze-substitution (HPF-FS) and cryo-sections of hydrated vitrified bacteria (CEMOVIS, Cryo-electron microscopy of vitreous sections) are described. At last, modern cryo-methods like cryo-electron tomography (CET) and cryo-FIB-SEM milling (focus ion beam-scanning electron microscopy) are introduced which are available only in specialized institutions, but at present represent the best available methods and techniques to study Gram-positive cell walls under close-to-nature conditions in great detail and at high resolution.
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Affiliation(s)
- Manfred Rohde
- Helmholtz Centre for Infection Research, HZI, Central Facility for Microscopy, ZEIM, Braunschweig, Germany
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88
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Esteban-Cuesta I, Dorn-In S, Drees N, Hölzel C, Gottschalk C, Gareis M, Schwaiger K. Antimicrobial resistance of Enterobacter cloacae complex isolates from the surface of muskmelons. Int J Food Microbiol 2019; 301:19-26. [PMID: 31071501 DOI: 10.1016/j.ijfoodmicro.2019.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/15/2019] [Accepted: 04/29/2019] [Indexed: 02/06/2023]
Abstract
The increasing antimicrobial resistance (AMR) among pathogenic and opportunistic pathogenic microorganisms is one of the main global public health problems. The consumption of food contaminated with such bacteria (ARB), especially of raw products, might result in the direct acquisition of ARB and in a spread of resistant bacteria along the food chain. The aim of the study was to characterize the antimicrobial susceptibility of potentially extended spectrum β-lactamase (ESBL) producing or AmpC resistant Enterobacteriaceae isolated from the surface of 147 muskmelons from wholesale and retail. A phenotypic analysis was carried out by using minimum inhibitory concentration (MIC) test strips for ESBL detection and MIC susceptibility plates against 14 antimicrobials. Furthermore, ESBL genes, sul-genes and plasmid-mediated AmpC resistance were analyzed by real-time PCR. Additionally, a further insight in the AmpC resistance of isolates of the Enterobacter cloacae complex (ECC) was obtained by analyzing the sequence of the ampC regulatory region (n = 15). A total of 73 potentially resistant Enterobacteriaceae were isolated from 56 muskmelons. Of these, 15 isolates of the ECC were suspicious for ESBL/AmpC resistance, and eleven thereof were positive for the AmpC family EBC. Phenotypic analysis showed diminished susceptibility against "critically" and "highly important" antimicrobials, according to the WHO classification. Furthermore, divergence in the ampC regulatory region was detected between the 15 isolates. These findings highlight the important role that raw produce might play in the transmission of antimicrobial resistances along the food chain.
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Affiliation(s)
- Irene Esteban-Cuesta
- Chair of Food Safety, Veterinary Faculty, Ludwig-Maximilians-University Munich, Schoenleutnerstrasse 8, 85764 Oberschleissheim, Germany.
| | - Samart Dorn-In
- Chair of Food Safety, Veterinary Faculty, Ludwig-Maximilians-University Munich, Schoenleutnerstrasse 8, 85764 Oberschleissheim, Germany
| | - Nathalie Drees
- Chair of Food Safety, Veterinary Faculty, Ludwig-Maximilians-University Munich, Schoenleutnerstrasse 8, 85764 Oberschleissheim, Germany
| | - Christina Hölzel
- Institute of Animal Breeding and Husbandry, Faculty of Agricultural and Nutritional Sciences, Christian-Albrechts University Kiel, Hermann-Rodewald-Str. 6, Kiel, Germany
| | - Christoph Gottschalk
- Chair of Food Safety, Veterinary Faculty, Ludwig-Maximilians-University Munich, Schoenleutnerstrasse 8, 85764 Oberschleissheim, Germany
| | - Manfred Gareis
- Chair of Food Safety, Veterinary Faculty, Ludwig-Maximilians-University Munich, Schoenleutnerstrasse 8, 85764 Oberschleissheim, Germany
| | - Karin Schwaiger
- Chair of Food Safety, Veterinary Faculty, Ludwig-Maximilians-University Munich, Schoenleutnerstrasse 8, 85764 Oberschleissheim, Germany
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89
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Erbilgin O, Rübel O, Louie KB, Trinh M, Raad MD, Wildish T, Udwary D, Hoover C, Deutsch S, Northen TR, Bowen BP. MAGI: A Method for Metabolite Annotation and Gene Integration. ACS Chem Biol 2019; 14:704-714. [PMID: 30896917 DOI: 10.1021/acschembio.8b01107] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabolomics is a widely used technology for obtaining direct measures of metabolic activities from diverse biological systems. However, ambiguous metabolite identifications are a common challenge and biochemical interpretation is often limited by incomplete and inaccurate genome-based predictions of enzyme activities (that is, gene annotations). Metabolite Annotation and Gene Integration (MAGI) generates a metabolite-gene association score using a biochemical reaction network. This is calculated by a method that emphasizes consensus between metabolites and genes via biochemical reactions. To demonstrate the potential of this method, we applied MAGI to integrate sequence data and metabolomics data collected from Streptomyces coelicolor A3(2), an extensively characterized bacterium that produces diverse secondary metabolites. Our findings suggest that coupling metabolomics and genomics data by scoring consensus between the two increases the quality of both metabolite identifications and gene annotations in this organism. MAGI also made biochemical predictions for poorly annotated genes that were consistent with the extensive literature on this important organism. This limited analysis suggests that using metabolomics data has the potential to improve annotations in sequenced organisms and also provides testable hypotheses for specific biochemical functions. MAGI is freely available for academic use both as an online tool at https://magi.nersc.gov and with source code available at https://github.com/biorack/magi .
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Affiliation(s)
- Onur Erbilgin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Oliver Rübel
- Data Analytics and Visualization Group, Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Katherine B. Louie
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew Trinh
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Markus de Raad
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tony Wildish
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Daniel Udwary
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Cindi Hoover
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Samuel Deutsch
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Trent R. Northen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Benjamin P. Bowen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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90
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Irazoki O, Hernandez SB, Cava F. Peptidoglycan Muropeptides: Release, Perception, and Functions as Signaling Molecules. Front Microbiol 2019; 10:500. [PMID: 30984120 PMCID: PMC6448482 DOI: 10.3389/fmicb.2019.00500] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/27/2019] [Indexed: 12/12/2022] Open
Abstract
Peptidoglycan (PG) is an essential molecule for the survival of bacteria, and thus, its biosynthesis and remodeling have always been in the spotlight when it comes to the development of antibiotics. The peptidoglycan polymer provides a protective function in bacteria, but at the same time is continuously subjected to editing activities that in some cases lead to the release of peptidoglycan fragments (i.e., muropeptides) to the environment. Several soluble muropeptides have been reported to work as signaling molecules. In this review, we summarize the mechanisms involved in muropeptide release (PG breakdown and PG recycling) and describe the known PG-receptor proteins responsible for PG sensing. Furthermore, we overview the role of muropeptides as signaling molecules, focusing on the microbial responses and their functions in the host beyond their immunostimulatory activity.
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Affiliation(s)
| | | | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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91
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Antibody neutralization of microbiota-derived circulating peptidoglycan dampens inflammation and ameliorates autoimmunity. Nat Microbiol 2019; 4:766-773. [DOI: 10.1038/s41564-019-0381-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 01/18/2019] [Indexed: 12/22/2022]
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92
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Kunath BJ, Delogu F, Naas AE, Arntzen MØ, Eijsink VGH, Henrissat B, Hvidsten TR, Pope PB. From proteins to polysaccharides: lifestyle and genetic evolution of Coprothermobacter proteolyticus. THE ISME JOURNAL 2019; 13:603-617. [PMID: 30315317 PMCID: PMC6461833 DOI: 10.1038/s41396-018-0290-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/11/2018] [Accepted: 09/19/2018] [Indexed: 11/29/2022]
Abstract
Microbial communities that degrade lignocellulosic biomass are typified by high levels of species- and strain-level complexity, as well as synergistic interactions between both cellulolytic and non-cellulolytic microorganisms. Coprothermobacter proteolyticus frequently dominates thermophilic, lignocellulose-degrading communities with wide geographical distribution, which is in contrast to reports that it ferments proteinaceous substrates and is incapable of polysaccharide hydrolysis. Here we deconvolute a highly efficient cellulose-degrading consortium (SEM1b) that is co-dominated by Clostridium (Ruminiclostridium) thermocellum and multiple heterogenic strains affiliated to C. proteolyticus. Metagenomic analysis of SEM1b recovered metagenome-assembled genomes (MAGs) for each constituent population, whereas in parallel two novel strains of C. proteolyticus were successfully isolated and sequenced. Annotation of all C. proteolyticus genotypes (two strains and one MAG) revealed their genetic acquisition of carbohydrate-active enzymes (CAZymes), presumably derived from horizontal gene transfer (HGT) events involving polysaccharide-degrading Firmicutes or Thermotogae-affiliated populations that are historically co-located. HGT material included a saccharolytic operon, from which a CAZyme was biochemically characterized and demonstrated hydrolysis of multiple hemicellulose polysaccharides. Finally, temporal genome-resolved metatranscriptomic analysis of SEM1b revealed expression of C. proteolyticus CAZymes at different SEM1b life stages as well as co-expression of CAZymes from multiple SEM1b populations, inferring deeper microbial interactions that are dedicated toward community degradation of cellulose and hemicellulose. We show that C. proteolyticus, a ubiquitous population, consists of closely related strains that have adapted via HGT to presumably degrade both oligo- and longer polysaccharides present in decaying plants and microbial cell walls, thus explaining its dominance in thermophilic anaerobic digesters on a global scale.
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Affiliation(s)
- Benoit J Kunath
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Francesco Delogu
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Adrian E Naas
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, Marseille, F-13288, France
| | - Torgeir R Hvidsten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Phillip B Pope
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, 1432, Norway.
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93
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Vermassen A, Leroy S, Talon R, Provot C, Popowska M, Desvaux M. Cell Wall Hydrolases in Bacteria: Insight on the Diversity of Cell Wall Amidases, Glycosidases and Peptidases Toward Peptidoglycan. Front Microbiol 2019; 10:331. [PMID: 30873139 PMCID: PMC6403190 DOI: 10.3389/fmicb.2019.00331] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
The cell wall (CW) of bacteria is an intricate arrangement of macromolecules, at least constituted of peptidoglycan (PG) but also of (lipo)teichoic acids, various polysaccharides, polyglutamate and/or proteins. During bacterial growth and division, there is a constant balance between CW degradation and biosynthesis. The CW is remodeled by bacterial hydrolases, whose activities are carefully regulated to maintain cell integrity or lead to bacterial death. Each cell wall hydrolase (CWH) has a specific role regarding the PG: (i) cell wall amidase (CWA) cleaves the amide bond between N-acetylmuramic acid and L-alanine residue at the N-terminal of the stem peptide, (ii) cell wall glycosidase (CWG) catalyses the hydrolysis of the glycosidic linkages, whereas (iii) cell wall peptidase (CWP) cleaves amide bonds between amino acids within the PG chain. After an exhaustive overview of all known conserved catalytic domains responsible for CWA, CWG, and CWP activities, this review stresses that the CWHs frequently display a modular architecture combining multiple and/or different catalytic domains, including some lytic transglycosylases as well as CW binding domains. From there, direct physiological and collateral roles of CWHs in bacterial cells are further discussed.
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Affiliation(s)
- Aurore Vermassen
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | - Régine Talon
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | | | - Magdalena Popowska
- Department of Applied Microbiology, Faculty of Biology, Institute of Microbiology, University of Warsaw, Warsaw, Poland
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
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94
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Schaub RE, Dillard JP. The Pathogenic Neisseria Use a Streamlined Set of Peptidoglycan Degradation Proteins for Peptidoglycan Remodeling, Recycling, and Toxic Fragment Release. Front Microbiol 2019; 10:73. [PMID: 30766523 PMCID: PMC6365954 DOI: 10.3389/fmicb.2019.00073] [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: 10/06/2018] [Accepted: 01/15/2019] [Indexed: 12/26/2022] Open
Abstract
Neisseria gonorrhoeae and Neisseria meningitidis release peptidoglycan (PG) fragments from the cell as the bacteria grow. For N. gonorrhoeae these PG fragments are known to cause damage to human Fallopian tube tissue in organ culture that mimics the damage seen in patients with pelvic inflammatory disease. N. meningitidis also releases pro-inflammatory PG fragments, but in smaller amounts than those from N. gonorrhoeae. It is not yet known if PG fragment release contributes to the highly inflammatory conditions of meningitis and meningococcemia caused by N. meningitidis. Examination of the mechanisms of PG degradation and recycling identified proteins required for these processes. In comparison to the model organism E. coli, the pathogenic Neisseria have far fewer PG degradation proteins, and some of these proteins show differences in subcellular localization compared to their E. coli homologs. In particular, some N. gonorrhoeae PG degradation proteins were demonstrated to be in the outer membrane while their homologs in E. coli were found free in the periplasm or in the cytoplasm. The localization of two of these proteins was demonstrated to affect PG fragment release. Another major factor for PG fragment release is the allele of ampG. Gonococcal AmpG was found to be slightly defective compared to related PG fragment permeases, thus leading to increased release of PG. A number of additional PG-related factors affect other virulence functions in Neisseria. Endopeptidases and carboxypeptidases were found to be required for type IV pilus production and resistance to hydrogen peroxide. Also, deacetylation of PG was required for virulence of N. meningitidis as well as normal cell size. Overall, we describe the processes involved in PG degradation and recycling and how certain characteristics of these proteins influence the interactions of these pathogens with their host.
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Affiliation(s)
- Ryan E Schaub
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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95
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Perez CE, Crawford JM. Characterization of a Hybrid Nonribosomal Peptide–Carbohydrate Biosynthetic Pathway in Photorhabdus luminescens. Biochemistry 2019; 58:1131-1140. [DOI: 10.1021/acs.biochem.8b01120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Corey E. Perez
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Chemical Biology Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Jason M. Crawford
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Chemical Biology Institute, Yale University, West Haven, Connecticut 06516, United States
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536, United States
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96
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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: 9] [Impact Index Per Article: 1.8] [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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97
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GlcNAc De- N-Acetylase from the Hyperthermophilic Archaeon Sulfolobus solfataricus. Appl Environ Microbiol 2019; 85:AEM.01879-18. [PMID: 30446550 DOI: 10.1128/aem.01879-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/04/2018] [Indexed: 01/17/2023] Open
Abstract
Sulfolobus solfataricus is an aerobic crenarchaeal hyperthermophile with optimum growth at temperatures greater than 80°C and pH 2 to 4. Within the crenarchaeal group of Sulfolobales, N-acetylglucosamine (GlcNAc) has been shown to be a component of exopolysaccharides, forming their biofilms, and of the N-glycan decorating some proteins. The metabolism of GlcNAc is still poorly understood in Archaea, and one approach to gaining additional information is through the identification and functional characterization of carbohydrate active enzymes (CAZymes) involved in the modification of GlcNAc. The screening of S. solfataricus extracts allowed the detection of a novel α-N-acetylglucosaminidase (α-GlcNAcase) activity, which has never been identified in Archaea Mass spectrometry analysis of the purified activity showed a protein encoded by the sso2901 gene. Interestingly, the purified recombinant enzyme, which was characterized in detail, revealed a novel de-N-acetylase activity specific for GlcNAc and derivatives. Thus, assays to identify an α-GlcNAcase found a GlcNAc de-N-acetylase instead. The α-GlcNAcase activity observed in S. solfataricus extracts did occur when SSO2901 was used in combination with an α-glucosidase. Furthermore, the inspection of the genomic context and the preliminary characterization of a putative glycosyltransferase immediately upstream of sso2901 (sso2900) suggest the involvement of these enzymes in the GlcNAc metabolism in S. solfataricus IMPORTANCE In this study, a preliminary screening of cellular extracts of S. solfataricus allowed the identification of an α-N-acetylglucosaminidase activity. However, the characterization of the corresponding recombinant enzyme revealed a novel GlcNAc de-N-acetylase, which, in cooperation with the α-glucosidase, catalyzed the hydrolysis of O-α-GlcNAc glycosides. In addition, we show that the product of a gene flanking the one encoding the de-N-acetylase is a putative glycosyltransferase, suggesting the involvement of the two enzymes in the metabolism of GlcNAc. The discovery and functional analysis of novel enzymatic activities involved in the modification of this essential sugar represent a powerful strategy to shed light on the physiology and metabolism of Archaea.
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Juan C, Torrens G, Barceló IM, Oliver A. Interplay between Peptidoglycan Biology and Virulence in Gram-Negative Pathogens. Microbiol Mol Biol Rev 2018; 82:e00033-18. [PMID: 30209071 PMCID: PMC6298613 DOI: 10.1128/mmbr.00033-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The clinical and epidemiological threat of the growing antimicrobial resistance in Gram-negative pathogens, particularly for β-lactams, the most frequently used and relevant antibiotics, urges research to find new therapeutic weapons to combat the infections caused by these microorganisms. An essential previous step in the development of these therapeutic solutions is to identify their potential targets in the biology of the pathogen. This is precisely what we sought to do in this review specifically regarding the barely exploited field analyzing the interplay among the biology of the peptidoglycan and related processes, such as β-lactamase regulation and virulence. Hence, here we gather, analyze, and integrate the knowledge derived from published works that provide information on the topic, starting with those dealing with the historically neglected essential role of the Gram-negative peptidoglycan in virulence, including structural, biogenesis, remodeling, and recycling aspects, in addition to proinflammatory and other interactions with the host. We also review the complex link between intrinsic β-lactamase production and peptidoglycan metabolism, as well as the biological costs potentially associated with the expression of horizontally acquired β-lactamases. Finally, we analyze the existing evidence from multiple perspectives to provide useful clues for identifying targets enabling the future development of therapeutic options attacking the peptidoglycan-virulence interconnection as a key weak point of the Gram-negative pathogens to be used, if not to kill the bacteria, to mitigate their capacity to produce severe infections.
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Affiliation(s)
- Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Isabel Maria Barceló
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - 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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Adu KT, Wilson R, Nichols DS, Baker AL, Bowman JP, Britz ML. Proteomic analysis of Lactobacillus casei GCRL163 cell-free extracts reveals a SecB homolog and other biomarkers of prolonged heat stress. PLoS One 2018; 13:e0206317. [PMID: 30359441 PMCID: PMC6201924 DOI: 10.1371/journal.pone.0206317] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 10/10/2018] [Indexed: 12/14/2022] Open
Abstract
Prolonged heat stress is one of the harsh conditions Lactobacillus casei strains encounter as non-starter lactic acid bacteria in dairy product manufacture. To understand the physiological and molecular mechanisms through which Lb. casei GCRL163 adapts to persistent elevated temperature, label-free quantitative proteomics of cell-free extracts was used to characterize the global responses of the strain cultured anaerobically in bioreactors at 30 to 45°C, pH 6.5, together with GC-MS for fatty acid methyl ester analysis at different growth phases. At higher growth temperatures, repression of energy-consuming metabolic pathways, such as fatty acid, nucleotide and amino acid biosynthesis, was observed, while PTS- and ABC-type transporter systems associated with uptake of nitrogen and carbon sources were up-regulated. Alkaline shock protein Asp23_2 was only detected at 45°C, expressed at high abundance, and presumptive α-L-fucosidase only at 40 and 45°C, with highly increased abundance (log2-fold change of 7) at 45°C. We identified a novel SecB homolog as a protein export chaperone putatively involved in posttranslational translocation systems, which was down-regulated as growth temperature increased and where the modelled 3D-structure shared architectural similarities with the Escherichia coli SecB protein. Membrane lipid analyses revealed temporal changes in fatty acid composition, cyclization of oleic acid to cyclopropane and novel cyclopentenyl moieties, and reduced synthesis of vaccenic acid, at higher temperatures. An 18kDa α-crystallin domain, Hsp20 family heat shock protein was more highly up-regulated in response to heat stress compared to other molecular chaperones, suggesting this protein could be a useful biomarker of prolonged heat stress in Lb. casei GCRL163.
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Affiliation(s)
- Kayode T. Adu
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, Tasmania, Australia
| | - David S. Nichols
- Central Science Laboratory, University of Tasmania, Hobart, Tasmania, Australia
| | - Anthony L. Baker
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - John P. Bowman
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Margaret L. Britz
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
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Dik DA, Batuecas MT, Lee M, Mahasenan KV, Marous DR, Lastochkin E, Fisher JF, Hermoso JA, Mobashery S. A Structural Dissection of the Active Site of the Lytic Transglycosylase MltE from Escherichia coli. Biochemistry 2018; 57:6090-6098. [PMID: 30256085 DOI: 10.1021/acs.biochem.8b00800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lytic transglycosylases (LTs) are bacterial enzymes that catalyze the cleavage of the glycan strands of the bacterial cell wall. The mechanism of this cleavage is a remarkable intramolecular transacetalization reaction, accomplished by an ensemble of active-site residues. Because the LT reaction occurs in parallel with the cell wall bond-forming reactions catalyzed by the penicillin-binding proteins, simultaneous inhibition of both enzymes can be particularly bactericidal to Gram-negative bacteria. The MltE lytic transglycosylase is the smallest of the eight LTs encoded by the Escherichia coli genome. Prior crystallographic and computational studies identified four active-site residues-E64, S73, S75, and Y192-as playing roles in catalysis. Each of these four residues was individually altered by mutation to give four variant enzymes (E64Q, S73A, S75A, and Y192F). All four variants showed reduced catalytic activity [soluble wild type (100%) > soluble Y192F and S75A (both 40%) > S73A (4%) > E64Q (≤1%)]. The crystal structure of each variant protein was determined at the resolution of 2.12 Å for E64Q, 2.33 Å for Y192F, 1.38 Å for S73A, and 1.35 Å for S75A. These variants show alteration of the hydrogen-bond interactions of the active site. Within the framework of a prior computational study of the LT mechanism, we suggest the mechanistic role of these four active-site residues in MltE catalysis.
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Affiliation(s)
- David A Dik
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
| | - María T Batuecas
- Department of Crystallography and Structural Biology , Inst. Química-Física "Rocasolano", CSIC , Serrano 119 , 28006 Madrid , Spain
| | - Mijoon Lee
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
| | - Kiran V Mahasenan
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
| | - Daniel R Marous
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
| | - Elena Lastochkin
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
| | - Jed F Fisher
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology , Inst. Química-Física "Rocasolano", CSIC , Serrano 119 , 28006 Madrid , Spain
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States
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