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Kwan JMC, Liang Y, Ng EWL, Sviriaeva E, Li C, Zhao Y, Zhang XL, Liu XW, Wong SH, Qiao Y. In silico MS/MS prediction for peptidoglycan profiling uncovers novel anti-inflammatory peptidoglycan fragments of the gut microbiota. Chem Sci 2024; 15:1846-1859. [PMID: 38303944 PMCID: PMC10829024 DOI: 10.1039/d3sc05819k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/19/2023] [Indexed: 02/03/2024] Open
Abstract
Peptidoglycan is an essential exoskeletal polymer across all bacteria. Gut microbiota-derived peptidoglycan fragments (PGNs) are increasingly recognized as key effector molecules that impact host biology. However, the current peptidoglycan analysis workflow relies on laborious manual identification from tandem mass spectrometry (MS/MS) data, impeding the discovery of novel bioactive PGNs in the gut microbiota. In this work, we built a computational tool PGN_MS2 that reliably simulates MS/MS spectra of PGNs and integrated it into the user-defined MS library of in silico PGN search space, facilitating automated PGN identification. Empowered by PGN_MS2, we comprehensively profiled gut bacterial peptidoglycan composition. Strikingly, the probiotic Bifidobacterium spp. manifests an abundant amount of the 1,6-anhydro-MurNAc moiety that is distinct from Gram-positive bacteria. In addition to biochemical characterization of three putative lytic transglycosylases (LTs) that are responsible for anhydro-PGN production in Bifidobacterium, we established that these 1,6-anhydro-PGNs exhibit potent anti-inflammatory activity in vitro, offering novel insights into Bifidobacterium-derived PGNs as molecular signals in gut microbiota-host crosstalk.
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Affiliation(s)
- Jeric Mun Chung Kwan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University 11 Mandalay Road 308232 Singapore
| | - Yaquan Liang
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Evan Wei Long Ng
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Ekaterina Sviriaeva
- Lee Kong Chian School of Medicine, Nanyang Technological University 11 Mandalay Road 308232 Singapore
| | - Chenyu Li
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Yilin Zhao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Xiao-Lin Zhang
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Xue-Wei Liu
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
| | - Sunny H Wong
- Lee Kong Chian School of Medicine, Nanyang Technological University 11 Mandalay Road 308232 Singapore
| | - Yuan Qiao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University 21 Nanyang Link 637371 Singapore
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Buthasane P, Roytrakul S, Phaonakrop N, Tunsagool P, Buthasane W, Am-in N, Suriyaphol G. Metaproteomic Analysis of Gut Resistome in the Cecal Microbiota of Fattening Pigs Raised without Antibiotics. Microbiol Spectr 2023; 11:e0222323. [PMID: 37439677 PMCID: PMC10433946 DOI: 10.1128/spectrum.02223-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 06/08/2023] [Indexed: 07/14/2023] Open
Abstract
Improper use of antibiotics in swine could reduce commensal bacteria and possibly increase pathogen infections via the gut resistome. This study aimed to compare the metaproteomic profiles of the gut resistome and related metabolism in the cecal microbiota of fattening pigs raised under antibiotic-free (ABF) conditions with those of ordinary industrial pigs (controls [CTRL]). The top three relatively abundant microbes in both groups were Escherichia coli, Ruminococcus, and Lactobacillus, followed by Bacteroides and Bifidobacterium. E. coli, Lactobacillus, and Bacteroides were found to be increased in the CTRL group, whereas Ruminococcus and Clostridium were greater in the ABF group. The highest abundances of antibiotic resistance proteins (log2 expression levels [ELs] of >10) were found to be for tetracycline resistance (Tetr) and aminoglycoside resistance (AMGr) proteins found in Bacteroides, with a significant increase in the CTRL group. High Tetr (ELs of 5.32) was found in Ruminococcus in the CTRL group, although pigs in both groups had never received tetracycline, possibly reflecting the influence of environments in farms. In E. coli, AMGr and β-lactamase family proteins were observed in both groups (ELs of 3 to 6), whereas multidrug resistance protein MdtL was significantly expressed in the CTRL group (ELs of around 3). In the ABF group, CRISPR-associated endonucleases Cas1 and Cas9, which function to defend against viruses, were markedly observed in Ruminococcus and Lactobacillus, respectively, with ELs of 8.6 and 4.15, respectively. In conclusion, this study demonstrated that CRISPR-associated endonucleases were markedly observed in the ABF group, whereas higher levels of Tetr, AMGr, and multidrug resistance protein MdtL was markedly observed in dominant bacterial species in the CTRL group. IMPORTANCE In order to control and reduce antibiotic use in animals, the Department of Livestock Development, Thailand, has launched a campaign for antibiotic-free livestock production. The present study has shown for the first time that CRISPR-associated endonucleases Cas1 and Cas9, which function to defend against viruses, were markedly observed in Ruminococcus and Lactobacillus, respectively, in ceca of pigs raised without antibiotics (ABF). The highest abundances of antibiotic resistance proteins were for tetracycline (Tetr) and aminoglycoside resistance (AMGr) proteins found in Bacteroides, with a significant increase in the controls. In E. coli, the microbe with the highest relative abundance, AMGr and β-lactamase family proteins were observed in both groups, whereas multidrug resistance protein MdtL was significantly expressed in the controls. Pigs in both ABF and control groups had never received tetracycline, possibly reflecting the influence of farm environments. We suggest that pigs raised without antibiotics may have more beneficial microorganisms for the gut than pigs raised with antibiotics.
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Affiliation(s)
- Pamornya Buthasane
- Biochemistry Unit, Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Sittiruk Roytrakul
- Functional Proteomics Technology Laboratory, Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Narumon Phaonakrop
- Functional Proteomics Technology Laboratory, Functional Ingredients and Food Innovation Research Group, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Paiboon Tunsagool
- Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand
| | - Wannapol Buthasane
- Biochemistry Unit, Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Nutthee Am-in
- Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Gunnaporn Suriyaphol
- Biochemistry Unit, Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
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Escobedo S, Pérez de Pipaon M, Rendueles C, Rodríguez A, Martínez B. Cell wall modifications that alter the exolytic activity of lactococcal phage endolysins have little impact on phage growth. Front Microbiol 2023; 14:1106049. [PMID: 36744092 PMCID: PMC9894900 DOI: 10.3389/fmicb.2023.1106049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/04/2023] [Indexed: 01/22/2023] Open
Abstract
Bacteriophages are a nuisance in the production of fermented dairy products driven by starter bacteria and strategies to reduce the risk of phage infection are permanently sought. Bearing in mind that the bacterial cell wall plays a pivotal role in host recognition and lysis, our goal was to elucidate to which extent modifications in the cell wall may alter endolysin activity and influence the outcome of phage infection in Lactococcus. Three lactococcal endolysins with distinct catalytic domains (CHAP, amidase and lysozyme) from phages 1,358, p2 and c2 respectively, were purified and their exolytic activity was tested against lactococcal mutants either overexpressing or lacking genes involved in the cell envelope stress (CES) response or in modifying peptidoglycan (PG) composition. After recombinant production in E. coli, Lys1358 (CHAP) and LysC2 (muramidase) were able to lyse lactococcal cells in turbidity reduction assays, but no activity of LysP2 was detected. The degree of PG acetylation, namely C6-O-acetylation and de-N-acetylation influenced the exolytic activity, being LysC2 more active against cells depleted of the PG deacetylase PgdA and the O-acetyl transferase OatA. On the contrary, both endolysins showed reduced activity on cells with an induced CES response. By measuring several growth parameters of phage c2 on these lactococcal mutants (lytic score, efficiency of plaquing, plaque size and one-step curves), a direct link between the exolytic activity of its endolysin and phage performance could not be stablished.
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Darmastuti A, Hasan PN, Wikandari R, Utami T, Rahayu ES, Suroto DA. Adhesion Properties of Lactobacillus plantarum Dad-13 and Lactobacillus plantarum Mut-7 on Sprague Dawley Rat Intestine. Microorganisms 2021; 9:2336. [PMID: 34835461 PMCID: PMC8625926 DOI: 10.3390/microorganisms9112336] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/02/2021] [Accepted: 11/08/2021] [Indexed: 11/16/2022] Open
Abstract
Adhesion capacity is considered one of the selection criteria for probiotic strains. The purpose of this study was to determine the adhesion properties of two candidate probiotics, Lactobacillus plantarum Dad-13 and Lactobacillus plantarum Mut-7. The evaluation included the hydrophobicity of the cell surface using microbial adhesion to hydrocarbons (MATH), autoaggregation, and the adhesion of L. plantarum Dad-13 and L. plantarum Mut-7 to the intestinal mucosa of Sprague Dawley rat, followed by genomic analysis of the two L. plantarum strains. L. plantarum Dad-13 and L. plantarum Mut-7 showed a high surface hydrophobicity (78.9% and 83.5%) and medium autoaggregation ability (40.9% and 57.5%, respectively). The exposure of both isolates to the surface of the rat intestine increased the total number of lactic acid bacteria on the colon compartment, from 2.9 log CFU/cm2 to 4.4 log CFU/cm2 in L. plantarum Dad-13 treatment and to 3.86 log CFU/cm2 in L. plantarum Mut-7 treatment. The results indicate the ability of two L. plantarum to attach to the surface of the rat intestine. The number of indigenous E. coli in the colon also decreased when the compartment was exposed to L. plantarum Dad-13 and Mut-7, from 2.9 log CFU/cm2 to 1 log CFU/cm2. Genomic analysis revealed that both strains have genes related to adhesion properties that could play an important role in increasing the adherence of probiotics to the intestinal mucosa such as gene encoding fibronectin-binding protein, chaperonin heat shock protein 33 (Hsp33), and genes related to the capsule and cell wall biosynthesis. Based on these findings, we believe that L. plantarum Dad-13 and L. plantarum Mut-7 have adhesion properties to the intestinal mucosa in the rat intestine model system. The present research will be essential to elucidate the molecular mechanism associated with adhesion in our two probiotic strains.
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Affiliation(s)
- Arum Darmastuti
- Faculty of Agricultural Technology, Universitas Gadjah Mada, Flora Street No 1 Bulaksumur, Yogyakarta 55281, Indonesia; (A.D.); (R.W.); (T.U.)
| | - Pratama N. Hasan
- Center for Food and Nutrition Studies, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia;
- University Center of Excellence for Research and Application on Integrated Probiotic Industry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Rachma Wikandari
- Faculty of Agricultural Technology, Universitas Gadjah Mada, Flora Street No 1 Bulaksumur, Yogyakarta 55281, Indonesia; (A.D.); (R.W.); (T.U.)
- Center for Food and Nutrition Studies, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia;
| | - Tyas Utami
- Faculty of Agricultural Technology, Universitas Gadjah Mada, Flora Street No 1 Bulaksumur, Yogyakarta 55281, Indonesia; (A.D.); (R.W.); (T.U.)
- Center for Food and Nutrition Studies, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia;
- University Center of Excellence for Research and Application on Integrated Probiotic Industry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Endang S. Rahayu
- Faculty of Agricultural Technology, Universitas Gadjah Mada, Flora Street No 1 Bulaksumur, Yogyakarta 55281, Indonesia; (A.D.); (R.W.); (T.U.)
- Center for Food and Nutrition Studies, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia;
- University Center of Excellence for Research and Application on Integrated Probiotic Industry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Dian Anggraini Suroto
- Faculty of Agricultural Technology, Universitas Gadjah Mada, Flora Street No 1 Bulaksumur, Yogyakarta 55281, Indonesia; (A.D.); (R.W.); (T.U.)
- Center for Food and Nutrition Studies, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia;
- University Center of Excellence for Research and Application on Integrated Probiotic Industry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
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5
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Ammam F, Patin D, Coullon H, Blanot D, Lambert T, Mengin-Lecreulx D, Candela T. AsnB is responsible for peptidoglycan precursor amidation in Clostridium difficile in the presence of vancomycin. MICROBIOLOGY-SGM 2021; 166:567-578. [PMID: 32375990 DOI: 10.1099/mic.0.000917] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Clostridium difficile 630 possesses a cryptic but functional gene cluster vanG Cd homologous to the vanG operon of Enterococcus faecalis. Expression of vanG Cd in the presence of subinhibitory concentrations of vancomycin is accompanied by peptidoglycan amidation on the meso-DAP residue. In this paper, we report the presence of two potential asparagine synthetase genes named asnB and asnB2 in the C. difficile genome whose products were potentially involved in this peptidoglycan structure modification. We found that asnB expression was only induced when C. difficile was grown in the presence of vancomycin, yet independently from the vanG Cd resistance and regulation operons. In addition, peptidoglycan precursors were not amidated when asnB was inactivated. No change in vancomycin MIC was observed in the asnB mutant strain. In contrast, overexpression of asnB resulted in the amidation of most of the C. difficile peptidoglycan precursors and in a weak increase of vancomycin susceptibility. AsnB activity was confirmed in E. coli. In contrast, the expression of the second asparagine synthetase, AsnB2, was not induced in the presence of vancomycin. In summary, our results demonstrate that AsnB is responsible for peptidoglycan amidation of C. difficile in the presence of vancomycin.
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Affiliation(s)
- Fariza Ammam
- Present address: Department of Engineering Science, University of Oxford, Parks Road, Oxford,OX1 3PJ, UK.,Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy en Josas, France
| | - Delphine Patin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Héloise Coullon
- Present address: Division of Infectious Diseases, Department of Medicine, Washington University, School of Medicine, St. Louis, MO, USA.,Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy en Josas, France
| | - Didier Blanot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Thierry Lambert
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy en Josas, France
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Thomas Candela
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy en Josas, France
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Martínez B, Rodríguez A, Kulakauskas S, Chapot-Chartier MP. Cell wall homeostasis in lactic acid bacteria: threats and defences. FEMS Microbiol Rev 2021; 44:538-564. [PMID: 32495833 PMCID: PMC7476776 DOI: 10.1093/femsre/fuaa021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Lactic acid bacteria (LAB) encompasses industrially relevant bacteria involved in food fermentations as well as health-promoting members of our autochthonous microbiota. In the last years, we have witnessed major progresses in the knowledge of the biology of their cell wall, the outermost macrostructure of a Gram-positive cell, which is crucial for survival. Sophisticated biochemical analyses combined with mutation strategies have been applied to unravel biosynthetic routes that sustain the inter- and intra-species cell wall diversity within LAB. Interplay with global cell metabolism has been deciphered that improved our fundamental understanding of the plasticity of the cell wall during growth. The cell wall is also decisive for the antimicrobial activity of many bacteriocins, for bacteriophage infection and for the interactions with the external environment. Therefore, genetic circuits involved in monitoring cell wall damage have been described in LAB, together with a plethora of defence mechanisms that help them to cope with external threats and adapt to harsh conditions. Since the cell wall plays a pivotal role in several technological and health-promoting traits of LAB, we anticipate that this knowledge will pave the way for the future development and extended applications of LAB.
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Affiliation(s)
- Beatriz Martínez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Ana Rodríguez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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Lysis of a Lactococcus lactis Dipeptidase Mutant and Rescue by Mutation in the Pleiotropic Regulator CodY. Appl Environ Microbiol 2020; 86:AEM.02937-19. [PMID: 32005740 PMCID: PMC7117943 DOI: 10.1128/aem.02937-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/22/2020] [Indexed: 12/13/2022] Open
Abstract
Lactococcus lactis subsp. cremoris MG1363 is a model for the lactic acid bacteria (LAB) used in the dairy industry. The proteolytic system, consisting of a proteinase, several peptide and amino acid uptake systems, and a host of intracellular peptidases, plays a vital role in nitrogen metabolism and is of eminent importance for flavor formation in dairy products. The dipeptidase PepV functions in the last stages of proteolysis. A link between nitrogen metabolism and peptidoglycan (PG) biosynthesis was underlined by the finding that deletion of the dipeptidase gene pepV (creating strain MGΔpepV) resulted in a prolonged lag phase when the mutant strain was grown with a high concentration of glycine. In addition, most MGΔpepV cells lyse and have serious defects in their shape. This phenotype is due to a shortage of alanine, since adding alanine can rescue the growth and shape defects. Strain MGΔpepV is more resistant to vancomycin, an antibiotic targeting peptidoglycan d-Ala-d-Ala ends, which confirmed that MGΔpepV has an abnormal PG composition. A mutant of MGΔpepV was obtained in which growth inhibition and cell shape defects were alleviated. Genome sequencing showed that this mutant has a single point mutation in the codY gene, resulting in an arginine residue at position 218 in the DNA-binding motif of CodY being replaced by a cysteine residue. Thus, this strain was named MGΔpepVcodY R218C Transcriptome sequencing (RNA-seq) data revealed a dramatic derepression in peptide uptake and amino acid utilization in MGΔpepVcodY R218C A model of the connections among PepV activity, CodY regulation, and PG synthesis of L. lactis is proposed.IMPORTANCE Precise control of peptidoglycan synthesis is essential in Gram-positive bacteria for maintaining cell shape and integrity as well as resisting stresses. Although neither the dipeptidase PepV nor alanine is essential for L. lactis MG1363, adequate availability of either ensures proper cell wall synthesis. We broaden the knowledge about the dipeptidase PepV, which acts as a linker between nitrogen metabolism and cell wall synthesis in L. lactis.
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Terai T, Kato K, Ishikawa E, Nakao M, Ito M, Miyazaki K, Kushiro A, Imai S, Nomura Y, Hanada N, Okumura T. Safety assessment of the candidate oral probiotic Lactobacillus crispatus YIT 12319: Analysis of antibiotic resistance and virulence-associated genes. Food Chem Toxicol 2020; 140:111278. [PMID: 32209355 DOI: 10.1016/j.fct.2020.111278] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 03/02/2020] [Accepted: 03/15/2020] [Indexed: 01/08/2023]
Abstract
Lactobacillus crispatus YIT 12319 (LcY) was isolated from the oral cavity of a healthy subject as a new candidate probiotic with potential benefits for oral health. As a safety assessment of LcY, we performed an antibiotic susceptibility test and virulence-associated gene analysis using a draft genome sequence. Susceptibility to 15 antibiotics was analyzed according to the standard method of the International Dairy Federation/International Organization for Standardization, as recommended by the European Food Safety Authority. The results showed that the minimum inhibitory concentrations of LcY were not higher than those of other L. crispatus strains, which have not acquired resistance to any antibiotics, suggesting that LcY had no externally acquired transmissible antibiotic resistance genes. Analysis of virulence-associated genes using the draft genome of LcY found that there were fewer potential virulence-associated genes in LcY than in other probiotics. These findings suggest that LcY could be a candidate probiotic based on its safety profile.
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Affiliation(s)
- Tomohiko Terai
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan.
| | - Kosuke Kato
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
| | - Eiji Ishikawa
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
| | - Masumi Nakao
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
| | - Masahiko Ito
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
| | - Kouji Miyazaki
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
| | - Akira Kushiro
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
| | - Susumu Imai
- Department of Translational Research, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa, 230-8501, Japan
| | - Yoshiaki Nomura
- Department of Translational Research, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa, 230-8501, Japan
| | - Nobuhiro Hanada
- Department of Translational Research, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa, 230-8501, Japan
| | - Takekazu Okumura
- Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo, 186-8650, Japan
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9
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Nöldeke ER, Stehle T. Unraveling the mechanism of peptidoglycan amidation by the bifunctional enzyme complex GatD/MurT: A comparative structural approach. Int J Med Microbiol 2019; 309:151334. [PMID: 31383542 DOI: 10.1016/j.ijmm.2019.151334] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 10/26/2022] Open
Abstract
The bacterial cell wall provides structural integrity to the cell and protects the cell from internal pressure and the external environment. During the course of the twelve-year funding period of the Collaborative Research Center 766, our work has focused on conducting structure-function studies of enzymes that modify (synthesize or cleave) cell wall components of a range of bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Nostoc punctiforme. Several of our structures represent promising targets for interference. In this review, we highlight a recent structure-function analysis of an enzyme complex that is responsible for the amidation of Lipid II, a peptidoglycan precursor, in S. aureus.
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Affiliation(s)
- Erik R Nöldeke
- Interfaculty Institute of Biochemistry, University of Tübingen, D-72076 Tübingen, Germany
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, D-72076 Tübingen, Germany; Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
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10
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Beaussart A, Beloin C, Ghigo JM, Chapot-Chartier MP, Kulakauskas S, Duval JFL. Probing the influence of cell surface polysaccharides on nanodendrimer binding to Gram-negative and Gram-positive bacteria using single-nanoparticle force spectroscopy. NANOSCALE 2018; 10:12743-12753. [PMID: 29946619 DOI: 10.1039/c8nr01766b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The safe use and design of nanoparticles (NPs) ask for a comprehensive interpretation of their potentially adverse effects on (micro)organisms. In this respect, the prior assessment of the interactions experienced by NPs in the vicinity of - and in contact with - complex biological surfaces is mandatory. It requires the development of suitable techniques for deciphering the processes that govern nano-bio interactions when a single organism is exposed to an extremely low dose of NPs. Here, we used atomic force spectroscopy (AFM)-based force measurements to investigate at the nanoscale the interactions between carboxylate-terminated polyamidoamine (PAMAM) nanodendrimers (radius ca. 4.5 nm) and two bacteria with very distinct surface properties, Escherichia coli and Lactococcus lactis. The zwitterionic nanodendrimers exhibit a negative peripheral surface charge and/or a positive intraparticulate core depending on the solution pH and salt concentration. Following an original strategy according to which a single dendrimer NP is grafted at the very apex of the AFM tip, the density and localization of NP binding sites are probed at the surface of E. coli and L. lactis mutants expressing different cell surface structures (presence/absence of the O-antigen of the lipopolysaccharides (LPS) or of a polysaccharide pellicle). In line with electrokinetic analysis, AFM force measurements evidence that adhesion of NPs onto pellicle-decorated L. lactis is governed by their underlying electrostatic interactions as controlled by the pH-dependent charge of the peripheral and internal NP components, and the negatively-charged cell surface. In contrast, the presence of the O-antigen on E. coli systematically suppresses the adhesion of nanodendrimers onto cells, may the apparent NP surface charge be determined by the peripheral carboxylate groups or by the internal amine functions. Altogether, this work highlights the differentiated roles played by surface polysaccharides in mediating NP attachment to Gram-positive and Gram-negative bacteria. It further demonstrates that the assessment of NP bioadhesion features requires a critical analysis of the electrostatic contributions stemming from the various structures composing the stratified cell envelope, and those originating from the bulk and surface NP components. The joint use of electrokinetics and AFM provides a valuable option for rapidly addressing the binding propensity of NPs to microorganisms, as urgently needed in NP risk assessments.
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Abstract
Lysozyme is a cornerstone of innate immunity. The canonical mechanism for bacterial killing by lysozyme occurs through the hydrolysis of cell wall peptidoglycan (PG). Conventional type (c-type) lysozymes are also highly cationic and can kill certain bacteria independently of PG hydrolytic activity. Reflecting the ongoing arms race between host and invading microorganisms, both gram-positive and gram-negative bacteria have evolved mechanisms to thwart killing by lysozyme. In addition to its direct antimicrobial role, more recent evidence has shown that lysozyme modulates the host immune response to infection. The degradation and lysis of bacteria by lysozyme enhance the release of bacterial products, including PG, that activate pattern recognition receptors in host cells. Yet paradoxically, lysozyme is important for the resolution of inflammation at mucosal sites. This review will highlight recent advances in our understanding of the diverse mechanisms that bacteria use to protect themselves against lysozyme, the intriguing immunomodulatory function of lysozyme, and the relationship between these features in the context of infection.
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Affiliation(s)
- Stephanie A. Ragland
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Alison K. Criss
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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12
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Tarazanova M, Huppertz T, Beerthuyzen M, van Schalkwijk S, Janssen P, Wels M, Kok J, Bachmann H. Cell Surface Properties of Lactococcus lactis Reveal Milk Protein Binding Specifically Evolved in Dairy Isolates. Front Microbiol 2017; 8:1691. [PMID: 28936202 PMCID: PMC5594101 DOI: 10.3389/fmicb.2017.01691] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 08/21/2017] [Indexed: 01/18/2023] Open
Abstract
Surface properties of bacteria are determined by the molecular composition of the cell wall and they are important for interactions of cells with their environment. Well-known examples of bacterial interactions with surfaces are biofilm formation and the fermentation of solid materials like food and feed. Lactococcus lactis is broadly used for the fermentation of cheese and buttermilk and it is primarily isolated from either plant material or the dairy environment. In this study, we characterized surface hydrophobicity, charge, emulsification properties, and the attachment to milk proteins of 55 L. lactis strains in stationary and exponential growth phases. The attachment to milk protein was assessed through a newly developed flow cytometry-based protocol. Besides finding a high degree of biodiversity, phenotype-genotype matching allowed the identification of candidate genes involved in the modification of the cell surface. Overexpression and gene deletion analysis allowed to verify the predictions for three identified proteins that altered surface hydrophobicity and attachment of milk proteins. The data also showed that lactococci isolated from a dairy environment bind higher amounts of milk proteins when compared to plant isolates. It remains to be determined whether the alteration of surface properties also has potential to alter starter culture functionalities.
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Affiliation(s)
- Mariya Tarazanova
- NIZOEde, Netherlands
- TI Food and NutritionWageningen, Netherlands
- Molecular Genetics, University of GroningenGroningen, Netherlands
| | - Thom Huppertz
- NIZOEde, Netherlands
- TI Food and NutritionWageningen, Netherlands
| | | | | | - Patrick Janssen
- NIZOEde, Netherlands
- TI Food and NutritionWageningen, Netherlands
| | - Michiel Wels
- NIZOEde, Netherlands
- TI Food and NutritionWageningen, Netherlands
| | - Jan Kok
- TI Food and NutritionWageningen, Netherlands
- Molecular Genetics, University of GroningenGroningen, Netherlands
| | - Herwig Bachmann
- NIZOEde, Netherlands
- TI Food and NutritionWageningen, Netherlands
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13
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Choi PH, Vu TMN, Pham HT, Woodward JJ, Turner MS, Tong L. Structural and functional studies of pyruvate carboxylase regulation by cyclic di-AMP in lactic acid bacteria. Proc Natl Acad Sci U S A 2017; 114:E7226-E7235. [PMID: 28808024 PMCID: PMC5584425 DOI: 10.1073/pnas.1704756114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cyclic di-3',5'-adenosine monophosphate (c-di-AMP) is a broadly conserved bacterial second messenger that has been implicated in a wide range of cellular processes. Our earlier studies showed that c-di-AMP regulates central metabolism in Listeria monocytogenes by inhibiting its pyruvate carboxylase (LmPC), a biotin-dependent enzyme with biotin carboxylase (BC) and carboxyltransferase (CT) activities. We report here structural, biochemical, and functional studies on the inhibition of Lactococcus lactis PC (LlPC) by c-di-AMP. The compound is bound at the dimer interface of the CT domain, at a site equivalent to that in LmPC, although it has a distinct binding mode in the LlPC complex. This binding site is not well conserved among PCs, and only a subset of these bacterial enzymes are sensitive to c-di-AMP. Conformational changes in the CT dimer induced by c-di-AMP binding may be the molecular mechanism for its inhibitory activity. Mutations of residues in the binding site can abolish c-di-AMP inhibition. In L. lactis, LlPC is required for efficient milk acidification through its essential role in aspartate biosynthesis. The aspartate pool in L. lactis is negatively regulated by c-di-AMP, and high aspartate levels can be restored by expression of a c-di-AMP-insensitive LlPC. LlPC has high intrinsic catalytic activity and is not sensitive to acetyl-CoA activation, in contrast to other PC enzymes.
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Affiliation(s)
- Philip H Choi
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Thu Minh Ngoc Vu
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Huong Thi Pham
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Mark S Turner
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072, Australia
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027;
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14
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Promoting acid resistance and nisin yield of Lactococcus lactis F44 by genetically increasing D-Asp amidation level inside cell wall. Appl Microbiol Biotechnol 2017. [PMID: 28643181 DOI: 10.1007/s00253-017-8365-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nisin fermentation by Lactococcus lactis requires a low pH to maintain a relatively higher nisin activity. However, the acidic environment will result in cell arrest, and eventually decrease the relative nisin production. Hence, constructing an acid-resistant L. lactis is crucial for nisin harvest in acidic nisin fermentation. In this paper, the first discovery of the relationship between D-Asp amidation-associated gene (asnH) and acid resistance was reported. Overexpression of asnH in L. lactis F44 (F44A) resulted in a sevenfold increase in survival capacity during acid shift (pH 3) and enhanced nisin desorption capacity compared to F44 (wild type), which subsequently contributed to higher nisin production, reaching 5346 IU/mL, 57.0% more than that of F44 in the fed-batch fermentation. Furthermore, the engineered F44A showed a moderate increase in D-Asp amidation level (from 82 to 92%) compared to F44. The concomitant decrease of the negative charge inside the cell wall was detected by a newly developed method based on the nisin adsorption amount onto cell surface. Meanwhile, peptidoglycan cross-linkage increased from 36.8% (F44) to 41.9% (F44A), and intracellular pH can be better maintained by blocking extracellular H+ due to the maintenance of peptidoglycan integrity, which probably resulted from the action of inhibiting hydrolases activity. The inference was further supported by the acmC-overexpression strain F44C, which was characterized by uncontrolled peptidoglycan hydrolase activity. Our results provided a novel strategy for enhancing nisin yield through cell wall remodeling, which contributed to both continuous nisin synthesis and less nisin adsorption in acidic fermentation (dual enhancement).
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15
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Solopova A, Formosa-Dague C, Courtin P, Furlan S, Veiga P, Péchoux C, Armalyte J, Sadauskas M, Kok J, Hols P, Dufrêne YF, Kuipers OP, Chapot-Chartier MP, Kulakauskas S. Regulation of Cell Wall Plasticity by Nucleotide Metabolism in Lactococcus lactis. J Biol Chem 2016; 291:11323-36. [PMID: 27022026 DOI: 10.1074/jbc.m116.714303] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 12/21/2022] Open
Abstract
To ensure optimal cell growth and separation and to adapt to environmental parameters, bacteria have to maintain a balance between cell wall (CW) rigidity and flexibility. This can be achieved by a concerted action of peptidoglycan (PG) hydrolases and PG-synthesizing/modifying enzymes. In a search for new regulatory mechanisms responsible for the maintenance of this equilibrium in Lactococcus lactis, we isolated mutants that are resistant to the PG hydrolase lysozyme. We found that 14% of the causative mutations were mapped in the guaA gene, the product of which is involved in purine metabolism. Genetic and transcriptional analyses combined with PG structure determination of the guaA mutant enabled us to reveal the pivotal role of the pyrB gene in the regulation of CW rigidity. Our results indicate that conversion of l-aspartate (l-Asp) to N-carbamoyl-l-aspartate by PyrB may reduce the amount of l-Asp available for PG synthesis and thus cause the appearance of Asp/Asn-less stem peptides in PG. Such stem peptides do not form PG cross-bridges, resulting in a decrease in PG cross-linking and, consequently, reduced PG thickness and rigidity. We hypothesize that the concurrent utilization of l-Asp for pyrimidine and PG synthesis may be part of the regulatory scheme, ensuring CW flexibility during exponential growth and rigidity in stationary phase. The fact that l-Asp availability is dependent on nucleotide metabolism, which is tightly regulated in accordance with the growth rate, provides L. lactis cells the means to ensure optimal CW plasticity without the need to control the expression of PG synthesis genes.
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Affiliation(s)
- Ana Solopova
- From the Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Cécile Formosa-Dague
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium, and
| | | | | | | | - Christine Péchoux
- Génétique Animale et Biologie Intégrative, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | | | | | - Jan Kok
- From the Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Pascal Hols
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium, and
| | - Yves F Dufrêne
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium, and
| | - Oscar P Kuipers
- From the Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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16
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Levefaudes M, Patin D, de Sousa-d'Auria C, Chami M, Blanot D, Hervé M, Arthur M, Houssin C, Mengin-Lecreulx D. Diaminopimelic Acid Amidation in Corynebacteriales: NEW INSIGHTS INTO THE ROLE OF LtsA IN PEPTIDOGLYCAN MODIFICATION. J Biol Chem 2015; 290:13079-94. [PMID: 25847251 DOI: 10.1074/jbc.m115.642843] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Indexed: 11/06/2022] Open
Abstract
A gene named ltsA was earlier identified in Rhodococcus and Corynebacterium species while screening for mutations leading to increased cell susceptibility to lysozyme. The encoded protein belonged to a huge family of glutamine amidotransferases whose members catalyze amide nitrogen transfer from glutamine to various specific acceptor substrates. We here describe detailed physiological and biochemical investigations demonstrating the specific role of LtsA protein from Corynebacterium glutamicum (LtsACg) in the modification by amidation of cell wall peptidoglycan diaminopimelic acid (DAP) residues. A morphologically altered but viable ΔltsA mutant was generated, which displays a high susceptibility to lysozyme and β-lactam antibiotics. Analysis of its peptidoglycan structure revealed a total loss of DAP amidation, a modification that was found in 80% of DAP residues in the wild-type polymer. The cell peptidoglycan content and cross-linking were otherwise not modified in the mutant. Heterologous expression of LtsACg in Escherichia coli yielded a massive and toxic incorporation of amidated DAP into the peptidoglycan that ultimately led to cell lysis. In vitro assays confirmed the amidotransferase activity of LtsACg and showed that this enzyme used the peptidoglycan lipid intermediates I and II but not, or only marginally, the UDP-MurNAc pentapeptide nucleotide precursor as acceptor substrates. As is generally the case for glutamine amidotransferases, either glutamine or NH4(+) could serve as the donor substrate for LtsACg. The enzyme did not amidate tripeptide- and tetrapeptide-truncated versions of lipid I, indicating a strict specificity for a pentapeptide chain length.
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Affiliation(s)
- Marjorie Levefaudes
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Delphine Patin
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Célia de Sousa-d'Auria
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Mohamed Chami
- the Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, CH-4058 Basel, Switzerland
| | - Didier Blanot
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Mireille Hervé
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France
| | - Michel Arthur
- INSERM, UMR S1138, Centre de Recherche des Cordeliers, Equipe 12, F-75006 Paris, France, the Sorbonne Universités, UPMC Université Paris 06, UMR S1138, Centre de Recherche des Cordeliers, F-75006 Paris, France, and the Université Paris-Descartes, Sorbonne Paris Cité, UMR S1138, Centre de Recherche des Cordeliers, F-75006, Paris, France
| | - Christine Houssin
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France,
| | - Dominique Mengin-Lecreulx
- From the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, F-91198 Gif-sur-Yvette, France,
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17
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Lipski A, Hervé M, Lombard V, Nurizzo D, Mengin-Lecreulx D, Bourne Y, Vincent F. Structural and biochemical characterization of the β-N-acetylglucosaminidase from Thermotoga maritima: toward rationalization of mechanistic knowledge in the GH73 family. Glycobiology 2014; 25:319-30. [PMID: 25344445 DOI: 10.1093/glycob/cwu113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Members of the GH73 glycosidase family cleave the β-1,4-glycosidic bond between the N-acetylglucosaminyl (GlcNAc) and N-acetylmuramyl (MurNAc) moieties in bacterial peptidoglycan. A catalytic mechanism has been proposed for members FlgJ, Auto, AcmA and Atl(WM) and the structural analysis of FlgJ and Auto revealed a conserved α/β fold reminiscent of the distantly related GH23 lysozyme. Comparison of the active site residues reveals variability in the nature of the catalytic general base suggesting two distinct catalytic mechanisms: an inverting mechanism involving two distant glutamate residues and a substrate-assisted mechanism involving anchimeric assistance by the C2-acetamido group of the GlcNAc moiety. Herein, we present the biochemical characterization and crystal structure of TM0633 from the hyperthermophilic bacterium Thermotoga maritima. TM0633 adopts the α/β fold of the family and displays β-N-acetylglucosaminidase activity on intact peptidoglycan sacculi. Site-directed mutagenesis identifies Glu34, Glu65 and Tyr118 as important residues for catalysis. A thorough bioinformatic analysis of the GH73 sequences identified five phylogenetic clusters. TM0633, FlgJ and Auto belong to a group of three clusters that conserve two carboxylate residues involved in a classical inverting acid-base mechanism. Members of the other two clusters lack a conserved catalytic general base supporting a substrate-assisted mechanism. Molecular modeling of representative members from each cluster suggests that variability in length of the β-hairpin region above the active site confers ligand-binding specificity and modulates the catalytic mechanisms within the GH73 family.
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Affiliation(s)
- Alexandra Lipski
- Laboratory for Biocrystallography and Structural Biology of Therapeutic Targets, Molecular and Structural Bases of Infectious Diseases, UMR 5086 CNRS and University of Lyon, 7 passage du Vercors, F-69367 Lyon Cedex 07, France CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
| | - Mireille Hervé
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, UMR 8619 CNRS, Université de Paris-Sud, 91405 Orsay, France
| | - Vincent Lombard
- CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France Aix-Marseille University, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
| | - Didier Nurizzo
- European Synchrotron Radiation Facility, Polygone Scientifique Louis Néel, 6 rue Jules Horowitz, 38000 Grenoble, France
| | - Dominique Mengin-Lecreulx
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, UMR 8619 CNRS, Université de Paris-Sud, 91405 Orsay, France
| | - Yves Bourne
- CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France Aix-Marseille University, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
| | - Florence Vincent
- CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France Aix-Marseille University, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
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18
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Abstract
The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts.
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19
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Chapot-Chartier MP. Interactions of the cell-wall glycopolymers of lactic acid bacteria with their bacteriophages. Front Microbiol 2014; 5:236. [PMID: 24904550 PMCID: PMC4033162 DOI: 10.3389/fmicb.2014.00236] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 04/30/2014] [Indexed: 11/17/2022] Open
Abstract
Lactic acid bacteria (LAB) are Gram positive bacteria widely used in the production of fermented food in particular cheese and yoghurts. Bacteriophage infections during fermentation processes have been for many years a major industrial concern and have stimulated numerous research efforts. Better understanding of the molecular mechanisms of bacteriophage interactions with their host bacteria is required for the development of efficient strategies to fight against infections. The bacterial cell wall plays key roles in these interactions. First, bacteriophages must adsorb at the bacterial surface through specific interactions with receptors that are cell wall components. At next step, phages must overcome the barrier constituted by cell wall peptidoglycan (PG) to inject DNA inside bacterial cell. Also at the end of the infection cycle, phages synthesize endolysins able to hydrolyze PG and lyse bacterial cells to release phage progeny. In the last decade, concomitant development of genomics and structural analysis of cell wall components allowed considerable advances in the knowledge of their structure and function in several model LAB. Here, we describe the present knowledge on the structure of the cell wall glycopolymers of the best characterized LAB emphasizing their structural variations and we present the available data regarding their role in bacteria-phage specific interactions at the different steps of the infection cycle.
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20
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Vieira D, Figueiredo TA, Verma A, Sobral RG, Ludovice AM, de Lencastre H, Trincao J. Purification, crystallization and preliminary X-ray diffraction analysis of GatD, a glutamine amidotransferase-like protein from Staphylococcus aureus peptidoglycan. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:632-5. [PMID: 24817726 DOI: 10.1107/s2053230x14007298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 04/01/2014] [Indexed: 11/10/2022]
Abstract
Amidation of peptidoglycan is an essential feature in Staphylococcus aureus that is necessary for resistance to β-lactams and lysozyme. GatD, a 27 kDa type I glutamine amidotransferase-like protein, together with MurT ligase, catalyses the amidation reaction of the glutamic acid residues of the peptidoglycan of S. aureus. The native and the selenomethionine-derivative proteins were crystallized using the sitting-drop vapour-diffusion method with polyethylene glycol, sodium acetate and calcium acetate. The crystals obtained diffracted beyond 1.85 and 2.25 Å, respectively, and belonged to space group P212121. X-ray diffraction data sets were collected at Diamond Light Source (on beamlines I02 and I04) and were used to obtain initial phases.
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Affiliation(s)
- Diana Vieira
- Macromolecular Crystallography Group and GlycoLab, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Teresa A Figueiredo
- Laboratory of Molecular Genetics, Microbiology of Human Pathogens Unit, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Anil Verma
- Oxford Protein Production Facility, Research Complex at Harwell, Didcot, England
| | - Rita G Sobral
- Laboratory of Molecular Genetics, Microbiology of Human Pathogens Unit, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana M Ludovice
- Laboratory of Molecular Genetics, Microbiology of Human Pathogens Unit, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
| | - Hermínia de Lencastre
- Laboratory of Molecular Genetics, Microbiology of Human Pathogens Unit, Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa, Oeiras, Portugal
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21
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Ito M, Kim YG, Tsuji H, Takahashi T, Kiwaki M, Nomoto K, Danbara H, Okada N. Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity. PLoS One 2014; 9:e83876. [PMID: 24416179 PMCID: PMC3885529 DOI: 10.1371/journal.pone.0083876] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 11/08/2013] [Indexed: 11/18/2022] Open
Abstract
Lactobacillus casei ATCC 27139 enhances host innate immunity, and the J1 phage-resistant mutants of this strain lose the activity. A transposon insertion mutant library of L. casei ATCC 27139 was constructed, and nine J1 phage-resistant mutants out of them were obtained. Cloning and sequencing analyses identified three independent genes that were disrupted by insertion of the transposon element: asnH, encoding asparagine synthetase, and dnaJ and dnaK, encoding the molecular chaperones DnaJ and DnaK, respectively. Using an in vivo mouse model of Listeria infection, only asnH mutant showed deficiency in their ability to enhance host innate immunity, and complementation of the mutation by introduction of the wild-type asnH in the mutant strain recovered the immuno-augmenting activity. AsnH protein exhibited asparagine synthetase activity when the lysozyme-treated cell wall extracts of L. casei ATCC 27139 was added as substrate. The asnH mutants lost the thick and rigid peptidoglycan features that are characteristic to the wild-type cells, indicating that AsnH of L. casei is involved in peptidoglycan biosynthesis. These results indicate that asnH is required for the construction of the peptidoglycan composition involved in the immune-activating capacity of L. casei ATCC 27139.
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Affiliation(s)
- Masahiro Ito
- Department of Microbiology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, Japan
| | - Yun-Gi Kim
- Department of Microbiology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, Japan
| | - Hirokazu Tsuji
- Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo, Japan
| | - Takuya Takahashi
- Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo, Japan
| | - Mayumi Kiwaki
- Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo, Japan
| | - Koji Nomoto
- Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo, Japan
| | - Hirofumi Danbara
- Department of Microbiology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, Japan
| | - Nobuhiko Okada
- Department of Microbiology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, Japan
- * E-mail:
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22
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Rahman A, Gleinser M, Lanhers MC, Riedel CU, Foligné B, Hanse M, Yen FT, Klouj A, Afzal MI, Back A, Mangavel C, Cailliez-Grimal C, Revol-Junelles AM, Borges F. Adaptation of the lactic acid bacterium Carnobacterium maltaromaticum LMA 28 to the mammalian gastrointestinal tract: From survival in mice to interaction with human cells. Int Dairy J 2014. [DOI: 10.1016/j.idairyj.2013.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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23
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Regulski K, Courtin P, Kulakauskas S, Chapot-Chartier MP. A novel type of peptidoglycan-binding domain highly specific for amidated D-Asp cross-bridge, identified in Lactobacillus casei bacteriophage endolysins. J Biol Chem 2013; 288:20416-26. [PMID: 23733182 DOI: 10.1074/jbc.m112.446344] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Peptidoglycan hydrolases (PGHs) are responsible for bacterial cell lysis. Most PGHs have a modular structure comprising a catalytic domain and a cell wall-binding domain (CWBD). PGHs of bacteriophage origin, called endolysins, are involved in bacterial lysis at the end of the infection cycle. We have characterized two endolysins, Lc-Lys and Lc-Lys-2, identified in prophages present in the genome of Lactobacillus casei BL23. These two enzymes have different catalytic domains but similar putative C-terminal CWBDs. By analyzing purified peptidoglycan (PG) degradation products, we showed that Lc-Lys is an N-acetylmuramoyl-L-alanine amidase, whereas Lc-Lys-2 is a γ-D-glutamyl-L-lysyl endopeptidase. Remarkably, both lysins were able to lyse only Gram-positive bacterial strains that possess PG with D-Ala(4)→D-Asx-L-Lys(3) in their cross-bridge, such as Lactococcus casei, Lactococcus lactis, and Enterococcus faecium. By testing a panel of L. lactis cell wall mutants, we observed that Lc-Lys and Lc-Lys-2 were not able to lyse mutants with a modified PG cross-bridge, constituting D-Ala(4)→L-Ala-(L-Ala/L-Ser)-L-Lys(3); moreover, they do not lyse the L. lactis mutant containing only the nonamidated D-Asp cross-bridge, i.e. D-Ala(4)→D-Asp-L-Lys(3). In contrast, Lc-Lys could lyse the ampicillin-resistant E. faecium mutant with 3→3 L-Lys(3)-D-Asn-L-Lys(3) bridges replacing the wild-type 4→3 D-Ala(4)-D-Asn-L-Lys(3) bridges. We showed that the C-terminal CWBD of Lc-Lys binds PG containing mainly D-Asn but not PG with only the nonamidated D-Asp-containing cross-bridge, indicating that the CWBD confers to Lc-Lys its narrow specificity. In conclusion, the CWBD characterized in this study is a novel type of PG-binding domain targeting specifically the D-Asn interpeptide bridge of PG.
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The quest for probiotic effector molecules—Unraveling strain specificity at the molecular level. Pharmacol Res 2013; 69:61-74. [DOI: 10.1016/j.phrs.2012.09.010] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 09/26/2012] [Accepted: 09/27/2012] [Indexed: 12/25/2022]
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The lysozyme-induced peptidoglycan N-acetylglucosamine deacetylase PgdA (EF1843) is required for Enterococcus faecalis virulence. J Bacteriol 2012; 194:6066-73. [PMID: 22961856 DOI: 10.1128/jb.00981-12] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lysozyme is a key component of the innate immune response in humans that provides a first line of defense against microbes. The bactericidal effect of lysozyme relies both on the cell wall lytic activity of this enzyme and on a cationic antimicrobial peptide activity that leads to membrane permeabilization. Among Gram-positive bacteria, the opportunistic pathogen Enterococcus faecalis has been shown to be extremely resistant to lysozyme. This unusual resistance is explained partly by peptidoglycan O-acetylation, which inhibits the enzymatic activity of lysozyme, and partly by d-alanylation of teichoic acids, which is likely to inhibit binding of lysozyme to the bacterial cell wall. Surprisingly, combined mutations abolishing both peptidoglycan O-acetylation and teichoic acid alanylation are not sufficient to confer lysozyme susceptibility. In this work, we identify another mechanism involved in E. faecalis lysozyme resistance. We show that exposure to lysozyme triggers the expression of EF1843, a protein that is not detected under normal growth conditions. Analysis of peptidoglycan structure from strains with EF1843 loss- and gain-of-function mutations, together with in vitro assays using recombinant protein, showed that EF1843 is a peptidoglycan N-acetylglucosamine deacetylase. EF1843-mediated peptidoglycan deacetylation was shown to contribute to lysozyme resistance by inhibiting both lysozyme enzymatic activity and, to a lesser extent, lysozyme cationic antimicrobial activity. Finally, EF1843 mutation was shown to reduce the ability of E. faecalis to cause lethality in the Galleria mellonella infection model. Taken together, our results reveal that peptidoglycan deacetylation is a component of the arsenal that enables E. faecalis to thrive inside mammalian hosts, as both a commensal and a pathogen.
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Kimoto-Nira H, Suzuki C, Aoki R, Kobayashi M, Mizumachi K. A derivative of Lactococcus lactis strain H61 with less interleukin-12 induction has a different cell wall. J Dairy Sci 2012; 95:2863-71. [PMID: 22612923 DOI: 10.3168/jds.2011-5129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/02/2012] [Indexed: 11/19/2022]
Abstract
Lactococcus lactis H61 can increase the cellular immune responses of aged (14-mo-old) senescence-accelerated mice. The aim of this study was to investigate the factors contributing to IL-12 induction by strain H61 by analyzing strains derived from it. Strain H61 derivative no. 13 was obtained by growing the parent strain at 37°C. This derivative induced significantly lower production of IL-12 from J774.1 macrophage cells than did the parent strain H61. The 2 strains differed in the resistance of their whole cells or cell walls to lysozyme, a cell wall-degrading enzyme. Sodium hydroxide treatment to de-O-acetylate muramic acid in the cell walls of the 2 strains reduced the lysozyme resistance, compared with untreated cell walls: at 3h after adding lysozyme, the lysozyme resistance of untreated and NaOH treated cell wall from strain H61 was 55.4% and 11.7%, respectively. The values of untreated and NaOH-treated cell walls from strain no.13 were 73.7 and 42.8%, respectively. The reduction was higher in strain H61, indicating that the cell walls of strain H61 were highly O-acetylated. Trichloroacetic acid treatment to remove wall-associated polymers such as teichoic acids made the lysozyme resistance of the cell walls of both strains similar. The sugar content of cell walls prepared from strain H61 was significantly higher than that of strain no. 13 cell wall. A derivative with less activity for inducing IL-12 by macrophage cells had less O-acetylation and had lower sugar content in the cell wall than did strain H61. Modifying the cell wall of strain H61 may be a useful way to regulate its ability to induce IL-12. Strain H61 has been used as a starter bacterium in the dairy industry. This study could lead to enhancing the value of dairy products made by strain H61 by characterizing the key factor(s) responsible for its stimulation of immunity.
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Affiliation(s)
- H Kimoto-Nira
- NARO Institute of Livestock and Grassland Science, Ikenodai 2, Tsukuba, Ibaraki 305-0901, Japan.
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Identification of the amidotransferase AsnB1 as being responsible for meso-diaminopimelic acid amidation in Lactobacillus plantarum peptidoglycan. J Bacteriol 2011; 193:6323-30. [PMID: 21949063 DOI: 10.1128/jb.05060-11] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The peptidoglycan (PG) of Lactobacillus plantarum contains amidated meso-diaminopimelic acid (mDAP). The functional role of this PG modification has never been characterized in any bacterial species, except for its impact on PG recognition by receptors of the innate immune system. In silico analysis of loci carrying PG biosynthesis genes in the L. plantarum genome revealed the colocalization of the murE gene, which encodes the ligase catalyzing the addition of mDAP to UDP-N-muramoyl-d-glutamate PG precursors, with asnB1, which encodes a putative asparagine synthase with an N-terminal amidotransferase domain. By gene disruption and complementation experiments, we showed that asnB1 is the amidotransferase involved in mDAP amidation. PG structural analysis revealed that mDAP amidation plays a key role in the control of the l,d-carboxypeptidase DacB activity. In addition, a mutant strain with a defect in mDAP amidation is strongly affected in growth and cell morphology, with filamentation and cell chaining, while a DacB-negative strain displays a phenotype very similar to that of a wild-type strain. These results suggest that mDAP amidation may play a critical role in the control of the septation process.
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Bernard E, Rolain T, Courtin P, Guillot A, Langella P, Hols P, Chapot-Chartier MP. Characterization of O-acetylation of N-acetylglucosamine: a novel structural variation of bacterial peptidoglycan. J Biol Chem 2011; 286:23950-8. [PMID: 21586574 DOI: 10.1074/jbc.m111.241414] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peptidoglycan (PG) N-acetyl muramic acid (MurNAc) O-acetylation is widely spread in gram-positive bacteria and is generally associated with resistance against lysozyme and endogenous autolysins. We report here the presence of O-acetylation on N-acetylglucosamine (GlcNAc) in Lactobacillus plantarum PG. This modification of glycan strands was never described in bacteria. Fine structural characterization of acetylated muropeptides released from L. plantarum PG demonstrated that both MurNAc and GlcNAc are O-acetylated in this species. These two PG post-modifications rely on two dedicated O-acetyltransferase encoding genes, named oatA and oatB, respectively. By analyzing the resistance to cell wall hydrolysis of mutant strains, we showed that GlcNAc O-acetylation inhibits N-acetylglucosaminidase Acm2, the major L. plantarum autolysin. In this bacterial species, inactivation of oatA, encoding MurNAc O-acetyltransferase, resulted in marked sensitivity to lysozyme. Moreover, MurNAc over-O-acetylation was shown to activate autolysis through the putative N-acetylmuramoyl-L-alanine amidase LytH enzyme. Our data indicate that in L. plantarum, two different O-acetyltransferases play original and antagonistic roles in the modulation of the activity of endogenous autolysins.
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Affiliation(s)
- Elvis Bernard
- INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France
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Imaging the nanoscale organization of peptidoglycan in living Lactococcus lactis cells. Nat Commun 2010; 1:27. [PMID: 20975688 PMCID: PMC2964452 DOI: 10.1038/ncomms1027] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 05/19/2010] [Indexed: 12/22/2022] Open
Abstract
Peptidoglycans provide bacterial cell walls with
mechanical strength. The spatial organization of peptidoglycan has previously been difficult
to study. Here, atomic force microscopy, together with cells carrying mutations in cell-wall
polysaccharides, has allowed an in-depth study of these molecules. The spatial organization of peptidoglycan, the major constituent of bacterial cell-walls,
is an important, yet still unsolved issue in microbiology. In this paper, we show that the
combined use of atomic force microscopy and cell wall mutants is a powerful platform for
probing the nanoscale architecture of cell wall peptidoglycan in living Gram-positive
bacteria. Using topographic imaging, we found that Lactococcus lactis wild-type cells
display a smooth, featureless surface morphology, whereas mutant strains lacking cell wall
exopolysaccharides feature 25-nm-wide periodic bands running parallel to the short axis of
the cell. In addition, we used single-molecule recognition imaging to show that parallel
bands are made of peptidoglycan. Our data, obtained for the first time on living ovococci,
argue for an architectural feature of the cell wall in the plane perpendicular to the long
axis of the cell. The non-invasive live cell experiments presented here open new avenues for
understanding the architecture and assembly of peptidoglycan in Gram-positive bacteria.
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Deghorain M, Fontaine L, David B, Mainardi JL, Courtin P, Daniel R, Errington J, Sorokin A, Bolotin A, Chapot-Chartier MP, Hallet B, Hols P. Functional and morphological adaptation to peptidoglycan precursor alteration in Lactococcus lactis. J Biol Chem 2010; 285:24003-13. [PMID: 20525686 DOI: 10.1074/jbc.m110.143636] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell wall peptidoglycan assembly is a tightly regulated process requiring the combined action of multienzyme complexes. In this study we provide direct evidence showing that substrate transformations occurring at the different stages of this process play a crucial role in the spatial and temporal coordination of the cell wall synthesis machinery. Peptidoglycan substrate alteration was investigated in the Gram-positive bacterium Lactococcus lactis by substituting the peptidoglycan precursor biosynthesis genes of this bacterium for those of the vancomycin-resistant bacterium Lactobacillus plantarum. A set of L. lactis mutant strains in which the normal d-Ala-ended precursors were partially or totally replaced by d-Lac-ended precursors was generated. Incorporation of the altered precursor into the cell wall induced morphological changes arising from a defect in cell elongation and cell separation. Structural analysis of the muropeptides confirmed that the activity of multiple enzymes involved in peptidoglycan synthesis was altered. Optimization of this altered pathway was necessary to increase the level of vancomycin resistance conferred by the utilization of d-Lac-ended peptidoglycan precursors in the mutant strains. The implications of these findings on the control of bacterial cell morphogenesis and the mechanisms of vancomycin resistance are discussed.
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Affiliation(s)
- Marie Deghorain
- Biochimie et Génétique Moléculaire Bactérienne, Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve 1348, Belgium
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Morinaga T, Kobayashi K, Ashida H, Fujita Y, Yoshida KI. Transcriptional regulation of the Bacillus subtilis asnH operon and role of the 5'-proximal long sequence triplication in RNA stabilization. MICROBIOLOGY-SGM 2010; 156:1632-1641. [PMID: 20185509 DOI: 10.1099/mic.0.036582-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Bacillus subtilis asnH operon, comprising yxbB, yxbA, yxnB, asnH and yxaM, is induced dramatically in the transition between exponential growth and stationary phase in rich sporulation medium. The asnH operon is transcribed to produce an unstable long transcript covering the entire operon as well as a short one corresponding to the first three genes. Northern blot analysis revealed that the discrete band corresponding to the short transcript was detectable even 1 h after the addition of excess rifampicin, suggesting its unusual stability. The transcription start site of the operon was determined; its corresponding promoter was most likely sigma-A dependent and under tight control of AbrB and CodY. Within the 5'-proximal region of the transcript preceding yxbB, there is a mysterious long sequence triplication (LST) segment, consisting of a tandem repeat of two highly conserved 118 bp units and a less conserved 129 bp unit. This LST segment was not involved in regulation by AbrB and CodY. Transcriptional fusion of the 5'-region containing the LST segment to lacZ resulted in a significant increase in beta-galactosidase synthesis in cells; the LST segment was thought to prevent degradation of the 5'-region-lacZ fusion transcript. These results suggest that the 5'-region containing the LST segment could function as an mRNA stabilizer that prolongs the lifetime of the transcript to which it is fused.
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Affiliation(s)
- Tetsuro Morinaga
- Department of Agrobioscience, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Kazuo Kobayashi
- Graduate School of Information Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma 630-0192, Japan
| | - Hitoshi Ashida
- Department of Agrobioscience, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Yasutaro Fujita
- Department of Biotechnology, Fukuyama University, 985 Sanzo, Higashimura, Fukuyama 729-0292, Japan
| | - Ken-Ichi Yoshida
- Department of Agrobioscience, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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Kleerebezem M, Hols P, Bernard E, Rolain T, Zhou M, Siezen RJ, Bron PA. The extracellular biology of the lactobacilli. FEMS Microbiol Rev 2010. [PMID: 20088967 DOI: 10.1111/j.1574-6976.2009.00208.x] [Citation(s) in RCA: 230] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Lactobacilli belong to the lactic acid bacteria, which play a key role in industrial and artisan food raw-material fermentation, including a large variety of fermented dairy products. Next to their role in fermentation processes, specific strains of Lactobacillus are currently marketed as health-promoting cultures or probiotics. The last decade has witnessed the completion of a large number of Lactobacillus genome sequences, including the genome sequences of some of the probiotic species and strains. This development opens avenues to unravel the Lactobacillus-associated health-promoting activity at the molecular level. It is generally considered likely that an important part of the Lactobacillus effector molecules that participate in the proposed health-promoting interactions with the host (intestinal) system resides in the bacterial cell envelope. For this reason, it is important to accurately predict the Lactobacillus exoproteomes. Extensive annotation of these exoproteomes, combined with comparative analysis of species- or strain-specific exoproteomes, may identify candidate effector molecules, which may support specific effects on host physiology associated with particular Lactobacillus strains. Candidate health-promoting effector molecules of lactobacilli can then be validated via mutant approaches, which will allow for improved strain selection procedures, improved product quality control criteria and molecular science-based health claims.
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