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Eitzen K, Sengupta P, Kroll S, Kemen E, Doehlemann G. A fungal member of the Arabidopsis thaliana phyllosphere antagonizes Albugo laibachii via a GH25 lysozyme. eLife 2021; 10:65306. [PMID: 33427195 PMCID: PMC7870139 DOI: 10.7554/elife.65306] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/10/2021] [Indexed: 12/22/2022] Open
Abstract
Plants are not only challenged by pathogenic organisms but also colonized by commensal microbes. The network of interactions these microbes establish with their host and among each other is suggested to contribute to the immune responses of plants against pathogens. In wild Arabidopsis thaliana populations, the oomycete pathogen Albugo laibachii plays an influential role in structuring the leaf phyllosphere. We show that the epiphytic yeast Moesziomyces bullatus ex Albugo on Arabidopsis, a close relative of pathogenic smut fungi, is an antagonistic member of the A. thaliana phyllosphere, which reduces infection of A. thaliana by A. laibachii. Combination of transcriptomics, reverse genetics, and protein characterization identified a GH25 hydrolase with lysozyme activity as a major effector of this microbial antagonism. Our findings broaden the understanding of microbial interactions within the phyllosphere, provide insights into the evolution of epiphytic basidiomycete yeasts, and pave the way for novel biocontrol strategies.
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Affiliation(s)
- Katharina Eitzen
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne, Germany.,Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Priyamedha Sengupta
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne, Germany
| | - Samuel Kroll
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Eric Kemen
- Max Planck Institute for Plant Breeding Research, Cologne, Germany.,Department of Microbial Interactions, IMIT/ZMBP, University of Tübingen, Tübingen, Germany
| | - Gunther Doehlemann
- Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Center for Molecular Biosciences, Cologne, Germany
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2
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Fu Y, Liang L, Deng S, Wu Y, Yuan Y, Gao M. Novel spore lytic enzyme from a Bacillus phage leading to spore killing. Enzyme Microb Technol 2020; 142:109698. [PMID: 33220860 DOI: 10.1016/j.enzmictec.2020.109698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 01/03/2023]
Abstract
Bacterial spores maintain metabolic dormancy and have high resistance to external pressure. Germination requires degradation of the spore cortex and the participation of germination-specific cortex-lytic enzymes (GSLEs). Previously reported GSLEs have been identified in bacteria and facilitate germination. In this study, we have characterized a novel spore lytic enzyme, Ply67, from Bacillus pumilus phage vB_BpuM_BpSp. Ply67 had a similar cortex-lytic activity to GSLEs but disrupted the inner membranes (IMs) of spores, leading to spore killing rather than germination. The amino acid sequence of the complete protein, Ply67FL, exhibited 40% homology to the GSLE SleB. Domain prediction showed that Ply67FL was composed of three domains: a signal peptide, N-terminal domain protein and C-terminal domain protein. Ply67FL rapidly caused E. coli cells lysis when it was expressed in E. coli. The protein containing the C-terminal domain protein, Ply67C, could kill B. pumilus spores. The protein containing the N-terminal domain protein, Ply67N, could combine with the decoated B. pumilus spores, indicating that N-terminal was the binding domain and C-terminal was the hydrolase domain. The protein lacking the signal peptide but containing the N-terminal and C-terminal domain proteins, Ply67, had activity against spores of various Bacillus species. The surface of spores treated with Ply67 shrank and the permeability barrier was disrupted, and the inner contents leaked out. Immunoelectron microscopic observation showed that Ply67 was mainly acted on the spore cortex. Overall, Ply67 is a novel spore lytic enzyme that differs from other GSLEs not only in amino acid sequence but also in activity against spores, and Ply67 might have the potential to kill spores of pathogenic Bacillus species, e.g., B. cereus and B. anthracis.
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Affiliation(s)
- Yajuan Fu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Leiqin Liang
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Sangsang Deng
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China
| | - Yan Wu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Yihui Yuan
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Meiying Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, PR China.
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3
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Shen A, Edwards AN, Sarker MR, Paredes-Sabja D. Sporulation and Germination in Clostridial Pathogens. Microbiol Spectr 2019; 7:10.1128/microbiolspec.GPP3-0017-2018. [PMID: 31858953 PMCID: PMC6927485 DOI: 10.1128/microbiolspec.gpp3-0017-2018] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Indexed: 12/14/2022] Open
Abstract
As obligate anaerobes, clostridial pathogens depend on their metabolically dormant, oxygen-tolerant spore form to transmit disease. However, the molecular mechanisms by which those spores germinate to initiate infection and then form new spores to transmit infection remain poorly understood. While sporulation and germination have been well characterized in Bacillus subtilis and Bacillus anthracis, striking differences in the regulation of these processes have been observed between the bacilli and the clostridia, with even some conserved proteins exhibiting differences in their requirements and functions. Here, we review our current understanding of how clostridial pathogens, specifically Clostridium perfringens, Clostridium botulinum, and Clostridioides difficile, induce sporulation in response to environmental cues, assemble resistant spores, and germinate metabolically dormant spores in response to environmental cues. We also discuss the direct relationship between toxin production and spore formation in these pathogens.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University Medical School, Boston, MA
| | - Adrianne N Edwards
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA
| | - Mahfuzur R Sarker
- Department of Microbiology, College of Science, Oregon State University, Corvallis, OR
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR
| | - Daniel Paredes-Sabja
- Department of Gut Microbiota and Clostridia Research Group, Departamento de Ciencias Biolo gicas, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile
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4
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Talukdar PK, Sarker MR. The serine proteases CspA and CspC are essential for germination of spores of Clostridium perfringens SM101 through activating SleC and cortex hydrolysis. Food Microbiol 2019; 86:103325. [PMID: 31703860 DOI: 10.1016/j.fm.2019.103325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 08/14/2019] [Accepted: 09/04/2019] [Indexed: 10/26/2022]
Abstract
Clostridium perfringens SM101 genome encodes three serine proteases (CspA, CspB, and CspC), and genetic evidence indicates that CspB is required for processing of pro-SleC into active SleC, an enzyme essential for degradation of the peptidoglycan cortex during spore germination. In this study, the expression of cspA and cspC, as well as the germination and colony formation by spores of cspAC and cspC mutants of strain SM101, were assessed. We demonstrated that 1) the cspA and cspC genes were expressed as a bicistronic operon only during sporulation in the mother cell compartment of SM101; 2) both cspAC and cspC mutant spores were unable to germinate significantly with either KCl, l-glutamine, brain heart infusion (BHI) broth, or a 1:1 chelate of Ca2+ and dipicolinic acid (DPA); 3) consistent with germination results, both cspAC and cspC mutant spores were defective in normal DPA release; 4) the colony formation by cspAC and cspC mutant spores was ~106-fold lower than that of wild-type spores, although decoated mutant spores yielded wild-type level colony formation on plates containing lysozyme; 5) no processing of inactive pro-SleC into active SleC was observed in cspAC and cspC mutant spores during germination; and finally, 6) the defects in germination, DPA release, colony formation and SleC processing in cspAC and cspC mutant spores were complemented by the wild-type cspA-cspC operon. Collectively, these results indicate that both CspA and CspC are essential for C. perfringens spore germination through activating SleC and inducing cortex hydrolysis.
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Affiliation(s)
- Prabhat K Talukdar
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR, 97331, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR, 97331, USA
| | - Mahfuzur R Sarker
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR, 97331, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR, 97331, USA.
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5
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Coelho D, Lopes PA, Cardoso V, Ponte P, Brás J, Madeira MS, Alfaia CM, Bandarra NM, Gerken HG, Fontes CMGA, Prates JAM. Novel combination of feed enzymes to improve the degradation of Chlorella vulgaris recalcitrant cell wall. Sci Rep 2019; 9:5382. [PMID: 30926940 PMCID: PMC6440988 DOI: 10.1038/s41598-019-41775-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 03/17/2019] [Indexed: 01/23/2023] Open
Abstract
In this study, a rational combination of 200 pre-selected Carbohydrate-Active enzymes (CAZymes) and sulfatases were tested, individually or combined, according to their ability to degrade Chlorella vulgaris cell wall to access its valuable nutritional compounds. The disruption of microalgae cell walls by a four-enzyme mixture (Mix) in comparison with the control, enabled to release up to 1.21 g/L of reducing sugars (p < 0.001), led to an eight-fold increase in oligosaccharides release (p < 0.001), and reduced the fluorescence intensity by 47% after staining with Calcofluor White (p < 0.001). The Mix treatment was successful in releasing proteins (p < 0.001), some MUFA (p < 0.05), and the beneficial 18:3n-3 fatty acid (p < 0.05). Even if no variation was detected for chlorophylls (p > 0.05), total carotenoids were increased in the supernatant (p < 0.05) from the Mix treatment, relative to the control. Taken together, these results indicate that this four-enzyme Mix displays an effective capacity to degrade C. vulgaris cell wall. Thus, these enzymes may constitute a good approach to improve the bioavailability of C. vulgaris nutrients for monogastric diets, in particular, and to facilitate the cost-effective use of microalgae by the feed industry, in general.
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Affiliation(s)
- Diogo Coelho
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477, Lisboa, Portugal
| | - Paula A Lopes
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477, Lisboa, Portugal
| | - Vânia Cardoso
- NZYTech - Genes and Enzymes, Estrada do Paço do Lumiar, Campus do Lumiar, Edifício E, 1649-038, Lisboa, Portugal
| | - Patrícia Ponte
- NZYTech - Genes and Enzymes, Estrada do Paço do Lumiar, Campus do Lumiar, Edifício E, 1649-038, Lisboa, Portugal
| | - Joana Brás
- NZYTech - Genes and Enzymes, Estrada do Paço do Lumiar, Campus do Lumiar, Edifício E, 1649-038, Lisboa, Portugal
| | - Marta S Madeira
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477, Lisboa, Portugal
| | - Cristina M Alfaia
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477, Lisboa, Portugal
| | - Narcisa M Bandarra
- DivAV, Instituto Português do Mar e da Atmosfera, Rua Alfredo Magalhães Ramalho, 1495-006, Lisboa, Portugal
| | - Henri G Gerken
- Arizona Center for Algae Technology and Innovation, Arizona State University, 7418 Innovation Way South, Building ISTB-3, Room 103, Mesa, Arizona, United States of America
| | - Carlos M G A Fontes
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477, Lisboa, Portugal.,NZYTech - Genes and Enzymes, Estrada do Paço do Lumiar, Campus do Lumiar, Edifício E, 1649-038, Lisboa, Portugal
| | - José A M Prates
- CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477, Lisboa, Portugal. .,NZYTech - Genes and Enzymes, Estrada do Paço do Lumiar, Campus do Lumiar, Edifício E, 1649-038, Lisboa, Portugal.
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6
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Pertel SS, Seryi SA, Kakayan ES. A new approach to the synthesis of lactams of muramic, isomuramic and normuramic acids via intramolecular O-alkylation: Stereochemical features of the intramolecular nucleophilic substitution. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.07.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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7
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Abstract
Bacterial endospores possess multiple integument layers, one of which is the cortex peptidoglycan wall. The cortex is essential for the maintenance of spore core dehydration and dormancy and contains structural modifications that differentiate it from vegetative cell peptidoglycan and determine its fate during spore germination. Following the engulfment stage of sporulation, the cortex is synthesized within the intermembrane space surrounding the forespore. Proteins responsible for cortex synthesis are produced in both the forespore and mother cell compartments. While some of these proteins also contribute to vegetative cell wall synthesis, others are sporulation specific. In order for the bacterial endospore to germinate and resume metabolism, the cortex peptidoglycan must first be degraded through the action of germination-specific lytic enzymes. These enzymes are present, yet inactive, in the dormant spore and recognize the muramic-δ-lactam modification present in the cortex. Germination-specific lytic enzymes across Bacillaceae and Clostridiaceae share this specificity determinant, which ensures that the spore cortex is hydrolyzed while the vegetative cell wall remains unharmed. Bacillus species tend to possess two redundant enzymes, SleB and CwlJ, capable of sufficient cortex degradation, while the clostridia have only one, SleC. Additional enzymes are often present that cannot initiate the cortex degradation process, but which can increase the rate of release of small fragments into the medium. Between the two families, the enzymes also differ in the enzymatic activities they possess and the mechanisms acting to restrict their activation until germination has been initiated.
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8
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Abstract
The ability of Clostridium perfringens to form spores plays a key role during the transmission of this Gram-positive bacterium to cause disease. Of particular note, the spores produced by food poisoning strains are often exceptionally resistant to food environment stresses such as heat, cold, and preservatives, which likely facilitates their survival in temperature-abused foods. The exceptional resistance properties of spores made by most type A food poisoning strains and some type C foodborne disease strains involve their production of a variant small acid-soluble protein-4 that binds more tightly to spore DNA than to the small acid-soluble protein-4 made by most other C. perfringens strains. Sporulation and germination by C. perfringens and Bacillus spp. share both similarities and differences. Finally, sporulation is essential for production of C. perfringens enterotoxin, which is responsible for the symptoms of C. perfringens type A food poisoning, the second most common bacterial foodborne disease in the United States. During this foodborne disease, C. perfringens is ingested with food and then, by using sporulation-specific alternate sigma factors, this bacterium sporulates and produces the enterotoxin in the intestines.
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9
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Al-Riyami B, Üstok FI, Stott K, Chirgadze DY, Christie G. The crystal structure of Clostridium perfringens SleM, a muramidase involved in cortical hydrolysis during spore germination. Proteins 2016; 84:1681-1689. [PMID: 27488615 DOI: 10.1002/prot.25112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/05/2016] [Accepted: 07/25/2016] [Indexed: 01/10/2023]
Abstract
Clostridium perfringens spores employ two peptidoglycan lysins to degrade the spore cortex during germination. SleC initiates cortex hydrolysis to generate cortical fragments that are degraded further by the muramidase SleM. Here, we present the crystal structure of the C. perfringens S40 SleM protein at 1.8 Å. SleM comprises an N-terminal catalytic domain that adopts an irregular α/β-barrel fold that is common to GH25 family lysozymes, plus a C-terminal fibronectin type III domain. The latter is involved in forming the SleM dimer that is evident in both the crystal structure and in solution. A truncated form of SleM that lacks the FnIII domain shows reduced activity against spore sacculi indicating that this domain may have a role in facilitating the position of substrate with respect to the enzyme's active site. Proteins 2016; 84:1681-1689. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bahja Al-Riyami
- Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Fatma Işık Üstok
- Department of Haematology, Division of Structural Medicine and Thrombosis Research Unit, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Katherine Stott
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Dimitri Y Chirgadze
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Graham Christie
- Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge, Cambridge, United Kingdom.
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10
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Meaney CA, Cartman ST, McClure PJ, Minton NP. Optimal spore germination in Clostridium botulinum ATCC 3502 requires the presence of functional copies of SleB and YpeB, but not CwlJ. Anaerobe 2015; 34:86-93. [PMID: 25937262 DOI: 10.1016/j.anaerobe.2015.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/10/2015] [Accepted: 04/28/2015] [Indexed: 10/23/2022]
Abstract
Germination, the process by which dormant endospores return to vegetative growth, is a critical process in the life cycle of the notorious pathogen Clostridium botulinum. Crucial is the degradation by hydrolytic enzymes of an inner peptidoglycan spore layer termed the cortex. Two mechanistically different systems of cortex lysis exist in spores of Clostridium species. C. botulinum ATCC 3502 harbours the Bacillus-like system of SleB, CwlJ and YpeB cortex lytic enzymes (CLEs). Through the construction of insertional gene knockout mutants in the sleB, cwlJ and ypeB genes of C. botulinum ATCC 3502 and the production of spores of each mutant strain, the effect on germination was assessed. This study demonstrates a reduced germination efficiency in spores carrying mutations in either sleB or ypeB with an approximate 2-fold reduction in heat resistant colony forming units (CFU/OD600) when plated on rich media. This reduction could be restored to wild-type levels by removing the spore coat and plating on media supplemented with lysozyme. It was observed that cwlJ spores displayed a similar germination efficiency as wild-type spores (P > 0.05). An optimal germinant commixture was identified to include a combination of l-alanine with sodium bicarbonate as it resulted in a 32% drop in OD600, while the additional incorporation of l-lactate resulted in a 57% decrease. Studies of the germination efficiency of spores prepared from all three CLE mutants was performed by monitoring the associated decrease in optical density but a germination defect was not observed in any of the CLE mutant strains. This was likely due to the lack of specificity of this particular assay. Taken together, these data indicate that functional copies of SleB and YpeB, but not CwlJ are required for the optimal germination of the spores of C. botulinum ATCC 3502.
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Affiliation(s)
- Carolyn A Meaney
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Stephen T Cartman
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | | | - Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
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Olguín-Araneda V, Banawas S, Sarker MR, Paredes-Sabja D. Recent advances in germination of Clostridium spores. Res Microbiol 2014; 166:236-43. [PMID: 25132133 DOI: 10.1016/j.resmic.2014.07.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 12/23/2022]
Abstract
Members of Clostridium genus are a diverse group of anaerobic spore-formers that includes several pathogenic species. Their anaerobic requirement enhances the importance of the dormant spore morphotype during infection, persistence and transmission. Bacterial spores are metabolically inactive and may survive for long times in the environment and germinate in presence of nutrients termed germinants. Recent progress with spores of several Clostridium species has identified the germinant receptors (GRs) involved in nutrient germinant recognition and initiation of spore germination. Signal transduction from GRs to the downstream effectors remains poorly understood but involves the release of dipicolinic acid. Two mechanistically different cortex hydrolytic machineries are present in Clostridium spores. Recent studies have also shed light into novel biological events that occur during spore formation (accumulation of transcriptional units) and transcription during early spore outgrowth. In summary, this review will cover all of the recent advances in Clostridium spore germination.
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Affiliation(s)
- Valeria Olguín-Araneda
- Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Saeed Banawas
- Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR, USA; Medical Laboratories Department, College of Science Al-Zulfi, Majmaah University, Saudi Arabia
| | - Mahfuzur R Sarker
- Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR, USA
| | - Daniel Paredes-Sabja
- Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile; Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA.
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12
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Role of YpeB in cortex hydrolysis during germination of Bacillus anthracis spores. J Bacteriol 2014; 196:3399-409. [PMID: 25022853 DOI: 10.1128/jb.01899-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common disinfection techniques. This study investigates the relationship between SleB, a GSLE in B. anthracis, and YpeB, a protein necessary for SleB stability and function. The results indicate that ΔsleB and ΔypeB spores exhibit similar germination phenotypes and that the two proteins have a strict codependency for their incorporation into the dormant spore. In the absence of its partner protein, SleB or YpeB is proteolytically degraded soon after expression during sporulation, rather than escaping the developing spore. The three PepSY domains of YpeB were examined for their roles in the interaction with SleB. YpeB truncation mutants illustrate the necessity of a region beyond the first PepSY domain for SleB stability. Furthermore, site-directed mutagenesis of highly conserved residues within the PepSY domains resulted in germination defects corresponding to reduced levels of both SleB and YpeB in the mutant spores. These results identify residues involved in the stability of both proteins and reiterate their codependent relationship. It is hoped that the study of GSLEs and interacting proteins will lead to the use of GSLEs as targets for efficient activation of spore germination and facilitation of spore cleanup.
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Lambert EA, Sherry N, Popham DL. In vitro and in vivo analyses of the Bacillus anthracis spore cortex lytic protein SleL. MICROBIOLOGY-SGM 2012; 158:1359-1368. [PMID: 22343356 DOI: 10.1099/mic.0.056630-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The bacterial endospore is the most resilient biological structure known. Multiple protective integument layers shield the spore core and promote spore dehydration and dormancy. Dormancy is broken when a spore germinates and becomes a metabolically active vegetative cell. Germination requires the breakdown of a modified layer of peptidoglycan (PG) known as the spore cortex. This study reports in vitro and in vivo analyses of the Bacillus anthracis SleL protein. SleL is a spore cortex lytic enzyme composed of three conserved domains: two N-terminal LysM domains and a C-terminal glycosyl hydrolase family 18 domain. Derivatives of SleL containing both, one or no LysM domains were purified and characterized. SleL is incapable of digesting intact cortical PG of either decoated spores or purified spore sacculi. However, SleL derivatives can hydrolyse fragmented PG substrates containing muramic-δ-lactam recognition determinants. The muropeptides that result from SleL hydrolysis are the products of N-acetylglucosaminidase activity. These muropeptide products are small and readily released from the cortex matrix. Loss of the LysM domain(s) decreases both PG binding and hydrolysis activity but these domains do not appear to determine specificity for muramic-δ-lactam. When the SleL derivatives are expressed in vivo, those proteins lacking one or both LysM domains do not associate with the spore. Instead, these proteins remain in the mother cell and are apparently degraded. SleL with both LysM domains localizes to the coat or cortex of the endospore. The information revealed by elucidating the role of SleL and its domains in B. anthracis sporulation and germination is important in designing new spore decontamination methods. By exploiting germination-specific lytic enzymes, eradication techniques may be greatly simplified.
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Affiliation(s)
- Emily A Lambert
- Department of Biological Sciences, Virginia Tech., Life Sciences I-MC0910, Blacksburg, VA 24061, USA
| | - Nora Sherry
- Department of Biological Sciences, Virginia Tech., Life Sciences I-MC0910, Blacksburg, VA 24061, USA
| | - David L Popham
- Department of Biological Sciences, Virginia Tech., Life Sciences I-MC0910, Blacksburg, VA 24061, USA
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Nariya H, Miyata S, Tamai E, Sekiya H, Maki J, Okabe A. Identification and characterization of a putative endolysin encoded by episomal phage phiSM101 of Clostridium perfringens. Appl Microbiol Biotechnol 2011; 90:1973-9. [PMID: 21484204 DOI: 10.1007/s00253-011-3253-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 12/15/2022]
Abstract
Clostridium perfringens produces potent toxins and histolytic enzymes, causing various diseases including life-threatening fulminant diseases in humans and other animals. Aiming at utilizing a phage endolysin as a therapeutic alternative to antibiotics, we surveyed the genome and bacteriophage sequences of C. perfringens. A phiSM101 muramidase gene (psm) revealed by this study can be assumed to encode an N-acetylmuramidase, since the N-terminal catalytic domain deduced from the gene shows high homology of those of N-acetylmuramidases. The psm gene is characteristic in that it is present in phiSM101, an episomal phage of enterotoxigenic C. perfringens type A strain, SM101, and also in that homologous genes are present in the genomes of all five C. perfringens toxin types. The psm gene was cloned and expressed in Escherichia coli as a protein histidine-tagged at the N-terminus (Psm-his). Psm-his was purified to homogeneity by nickel-charged immobilized metal affinity chromatography and anion-exchange chromatography. The purified enzyme lysed cells of all C. perfringens toxin types but not other clostridial species tested, as was shown by a turbidity reduction assay. These results indicate the Psm-his is useful as a cell-wall lytic enzyme and also suggest that it is potentially useful for biocontrol of this organism.
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Affiliation(s)
- Hirofumi Nariya
- Department of Microbiology, Faculty of Medicine, Kagawa University, 1750-1 Miki-cho, Kita-gun, Kagawa, Japan.
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15
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Lysozyme as a barrier to growth of Bacillus anthracis strain Sterne in liquid egg white, milk and beef. Food Microbiol 2011; 28:1231-4. [PMID: 21645824 DOI: 10.1016/j.fm.2011.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 03/03/2011] [Accepted: 03/05/2011] [Indexed: 11/23/2022]
Abstract
In this study, we investigated the role of lysozyme on the viability of Bacillus cereus, Bacillus subtilis, Bacillus pumilus and Bacillus anthracis (Sterne) in egg white (EW), ground beef and milk. At 35 °C in EW, growth rates (GR) for B. cereus, B. subtilis, B. pumilus and B. anthracis were 0.005, -0.018, -0.028 and -0.029 OD(600)/h, respectively. Heat-treating EW at 55 and 60 °C reduced the inactivating effect of EW by 3.1 and 10.5-fold, respectively. Addition of lysozyme (2 mg/ml) to 60 °C-treated EW increased the inactivation rate 5.76-fold, indicating involvement of lysozyme in B. anthracis inactivation. B. anthracis inactivation was influenced by pH, as shown by a progressive increase in inactivation rate from 0.25 to -4.42 logs CFU/h over a pH range of 6.0-8.5. Adding 2 mg/ml lysozyme to milk and ground beef also suppressed the growth of B. anthracis 3.3 and 6.5-fold, respectively. These data indicate that lysozyme, as a natural component of EW or potential additive in other foods, could reduce biothreat risks presented by bioterror agents.
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16
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Paredes-Sabja D, Sarker MR. Effect of the cortex-lytic enzyme SleC from non-food-borne Clostridium perfringens on the germination properties of SleC-lacking spores of a food poisoning isolate. Can J Microbiol 2010; 56:952-8. [PMID: 21076486 DOI: 10.1139/w10-083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hallmark of bacterial spore germination is peptidoglycan cortex hydrolysis by cortex-lytic enzymes. In spores of Clostridium perfringens wild-type strain SM101, which causes food poisoning, the sole essential cortex-lytic enzyme SleC is activated by a unique serine protease CspB. Interestingly, the non-food-borne wild-type strain F4969 encodes a significantly divergent SleC variant (SleCF4969) and 3 serine proteases (CspA, CspB, and CspC). Consequently, in this study we evaluated the functional compatibility of SleCF4969 and SleCSM101 by complementing the germination phenotypes of SM101ΔsleC spores with sleCF4969. Our results show that although pro-SleCF4969 was processed into mature SleCF4969 in the SM101ΔsleC spores, it partially restored spore germination with nutrient medium, with a mixture of ʟ-asparagine and KCl, or with a 1:1 chelate of Ca2+ and dipicolinic acid. While the amount of dipicolinic acid released was lower, the amount of hexosamine-containing material released during germination of SM101ΔsleC(sleCF4969) spores was similar to the amount released during germination of SM101 wild-type spores. The viability of SM101ΔsleC(sleCF4969) spores was 8- and 3-fold lower than that of SM101 and F4969 spores, respectively. Together, these data indicate that the peptidoglycan cortex hydrolysis machinery in the food poisoning isolate SM101 is functionally divergent than that in the non-food-borne isolate F4969.
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Affiliation(s)
- Daniel Paredes-Sabja
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
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17
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Clostridial spore germination versus bacilli: genome mining and current insights. Food Microbiol 2010; 28:266-74. [PMID: 21315983 DOI: 10.1016/j.fm.2010.03.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/24/2010] [Accepted: 03/25/2010] [Indexed: 11/23/2022]
Abstract
Bacilli and clostridia share the characteristic of forming metabolically inactive endospores. Spores are highly resistant to adverse environmental conditions including heat, and their ubiquitous presence in nature makes them inevitable contaminants of foods and food ingredients. Spores can germinate under favourable conditions, and the following outgrowth can lead to food spoilage and foodborne illness. Germination of spores has been best studied in Bacillus species, but the process of spore germination is less well understood in anaerobic clostridia. This paper describes a genome mining approach focusing on the genes related to spore germination of clostridia. To this end, 12 representative sequenced Bacillus genomes and 24 Clostridium genomes were analyzed for the distribution of known and putative germination-related genes and their homologues. Overall, the number of ger operons encoding germinant receptors is lower in clostridia than in bacilli, and some Clostridium species are predicted to produce cortex-lytic enzymes that are different from the ones encountered in bacilli. The in silico germination model constructed for clostridia was linked to recently obtained experimental data for selected germination determinants, mainly in Clostridium perfringens. Similarities and differences between germination mechanisms of bacilli and clostridia will be discussed.
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Characterization of Acp, a peptidoglycan hydrolase of Clostridium perfringens with N-acetylglucosaminidase activity that is implicated in cell separation and stress-induced autolysis. J Bacteriol 2010; 192:2373-84. [PMID: 20190047 DOI: 10.1128/jb.01546-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This work reports the characterization of the first known peptidoglycan hydrolase (Acp) produced mainly during vegetative growth of Clostridium perfringens. Acp has a modular structure with three domains: a signal peptide domain, an N-terminal domain with repeated sequences, and a C-terminal catalytic domain. The purified recombinant catalytic domain of Acp displayed lytic activity on the cell walls of several Gram-positive bacterial species. Its hydrolytic specificity was established by analyzing the Bacillus subtilis peptidoglycan digestion products by coupling reverse phase-high-pressure liquid chromatography (RP-HPLC) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis, which displayed an N-acetylglucosaminidase activity. The study of acp expression showed a constant expression during growth, which suggested an important role of Acp in growth of C. perfringens. Furthermore, cell fractionation and indirect immunofluorescence staining using anti-Acp antibodies revealed that Acp is located at the septal peptidoglycan of vegetative cells during exponential growth phase, indicating a role in cell separation or division of C. perfringens. A knockout acp mutant strain was obtained by using the insertion of mobile group II intron strategy (ClosTron). The microscopic examination indicated a lack of vegetative cell separation in the acp mutant strain, as well as the wild-type strain incubated with anti-Acp antibodies, demonstrating the critical role of Acp in cell separation. The comparative responses of wild-type and acp mutant strains to stresses induced by Triton X-100, bile salts, and vancomycin revealed an implication of Acp in autolysis induced by these stresses. Overall, Acp appears as a major cell wall N-acetylglucosaminidase implicated in both vegetative growth and stress-induced autolysis.
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Contributions of four cortex lytic enzymes to germination of Bacillus anthracis spores. J Bacteriol 2009; 192:763-70. [PMID: 19966006 DOI: 10.1128/jb.01380-09] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bacterial spores remain dormant and highly resistant to environmental stress until they germinate. Completion of germination requires the degradation of spore cortex peptidoglycan by germination-specific lytic enzymes (GSLEs). Bacillus anthracis has four GSLEs: CwlJ1, CwlJ2, SleB, and SleL. In this study, the cooperative action of all four GSLEs in vivo was investigated by combining in-frame deletion mutations to generate all possible double, triple, and quadruple GSLE mutant strains. Analyses of mutant strains during spore germination and outgrowth combined observations of optical density loss, colony-producing ability, and quantitative identification of spore cortex fragments. The lytic transglycosylase SleB alone can facilitate enough digestion to allow full spore viability and generates a variety of small and large cortex fragments. CwlJ1 is also sufficient to allow completion of nutrient-triggered germination independently and is a major factor in Ca(2+)-dipicolinic acid (DPA)-triggered germination, but its enzymatic activity remains unidentified because its products are large and not readily released from the spore's integuments. CwlJ2 contributes the least to overall cortex digestion but plays a subsidiary role in Ca(2+)-DPA-induced germination. SleL is an N-acetylglucosaminidase that plays the major role in hydrolyzing the large products of other GSLEs into small, rapidly released muropeptides. As the roles of these enzymes in cortex degradation become clearer, they will be targets for methods to stimulate premature germination of B. anthracis spores, greatly simplifying decontamination measures.
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SleC is essential for germination of Clostridium difficile spores in nutrient-rich medium supplemented with the bile salt taurocholate. J Bacteriol 2009; 192:657-64. [PMID: 19933358 DOI: 10.1128/jb.01209-09] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Clostridium difficile is the major cause of infectious diarrhea and a major burden to health care services. The ability of this organism to form endospores plays a pivotal role in infection and disease transmission. Spores are highly resistant to many forms of disinfection and thus are able to persist on hospital surfaces and disseminate infection. In order to cause disease, the spores must germinate and the organism must grow vegetatively. Spore germination in Bacillus is well understood, and genes important for this process have recently been identified in Clostridium perfringens; however, little is known about C. difficile. Apparent homologues of the spore cortex lytic enzyme genes cwlJ and sleB (Bacillus subtilis) and sleC (C. perfringens) are present in the C. difficile genome, and we describe inactivation of these homologues in C. difficile 630Delta erm and a B1/NAP1/027 clinical isolate. Spores of a sleC mutant were unable to form colonies when germination was induced with taurocholate, although decoated sleC spores formed the same number of heat-resistant colonies as the parental control, even in the absence of germinants. This suggests that sleC is absolutely required for conversion of spores to vegetative cells, in contrast to CD3563 (a cwlJ/sleB homologue), inactivation of which had no effect on germination and outgrowth of C. difficile spores under the same conditions. The B1/NAP1/027 strain R20291 was found to sporulate more slowly and produce fewer spores than 630Delta erm. Furthermore, fewer R20291 spores germinated, indicating that there are differences in both sporulation and germination between these epidemic and nonepidemic C. difficile isolates.
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21
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SleC is essential for cortex peptidoglycan hydrolysis during germination of spores of the pathogenic bacterium Clostridium perfringens. J Bacteriol 2009; 191:2711-20. [PMID: 19218389 DOI: 10.1128/jb.01832-08] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Clostridial spore germination requires degradation of the spore's peptidoglycan (PG) cortex by cortex-lytic enzymes (CLEs), and two Clostridium perfringens CLEs, SleC and SleM, degrade cortex PG in vitro. We now find that only SleC is essential for cortex hydrolysis and viability of C. perfringens spores. C. perfringens sleC spores did not germinate completely with nutrients, KCl, or a 1:1 chelate of Ca(2+) and dipicolinic acid (Ca-DPA), and the colony-forming efficiency of sleC spores was 10(3)-fold lower than that of wild-type spores. However, sleC spores incubated with various germinants released most of their DPA, although slower than wild-type or sleM spores, and DPA release from sleC sleM spores was very slow. In contrast, germination and viability of sleM spores were similar to that of wild-type spores, although sleC sleM spores had 10(5)-fold-lower viability. These results allow the following conclusions about C. perfringens spore germination: (i) SleC is essential for cortex hydrolysis; (ii) although SleM can degrade cortex PG in vitro, this enzyme is not essential; (iii) action of SleC alone or with SleM can accelerate DPA release; and (iv) Ca-DPA does not trigger spore germination by activation of CLEs.
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22
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Roles of germination-specific lytic enzymes CwlJ and SleB in Bacillus anthracis. J Bacteriol 2009; 191:2237-47. [PMID: 19181808 DOI: 10.1128/jb.01598-08] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The structural characteristics of a spore enable it to withstand stresses that typically kill a vegetative cell. Spores remain dormant until small molecule signals induce them to germinate into vegetative bacilli. Germination requires degradation of the thick cortical peptidoglycan by germination-specific lytic enzymes (GSLEs). Bacillus anthracis has four putative GSLEs, based upon sequence similarities with enzymes in other species: SleB, CwlJ1, CwlJ2, and SleL. In this study, the roles of SleB, CwlJ1, and CwlJ2 were examined. The expression levels of all three genes peak 3.5 h into sporulation. Genetic analysis revealed that, similar to other known GSLEs, none of these gene products are individually required for growth, sporulation, or triggering of germination. However, later germination events are affected in spores lacking CwlJ1 or SleB. Compared to the wild type, germinating spores without CwlJ1 suffer a delay in optical density loss and cortex peptidoglycan release. The absence of SleB also causes a delay in cortex fragment release. A double mutant lacking both SleB and CwlJ1 is completely blocked in cortex hydrolysis and progresses through outgrowth to produce colonies at a frequency 1,000-fold lower than that of the wild-type strain. A null mutation eliminating CwlJ2 has no effect on germination. High-performance liquid chromatography and mass spectroscopy analysis revealed that SleB is required for lytic transglycosylase activity. CwlJ1 also clearly participates in cortex hydrolysis, but its specific mode of action remains unclear. Understanding the lytic germination activities that naturally diminish spore resistance can lead to methods for prematurely inducing them, thus simplifying the process of treating contaminated sites.
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Characterization of Clostridium perfringens spores that lack SpoVA proteins and dipicolinic acid. J Bacteriol 2008; 190:4648-59. [PMID: 18469104 DOI: 10.1128/jb.00325-08] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Spores of Clostridium perfringens possess high heat resistance, and when these spores germinate and return to active growth, they can cause gastrointestinal disease. Work with Bacillus subtilis has shown that the spore's dipicolinic acid (DPA) level can markedly influence both spore germination and resistance and that the proteins encoded by the spoVA operon are essential for DPA uptake by the developing spore during sporulation. We now find that proteins encoded by the spoVA operon are also essential for the uptake of Ca(2+) and DPA into the developing spore during C. perfringens sporulation. Spores of a spoVA mutant had little, if any, Ca(2+) and DPA, and their core water content was approximately twofold higher than that of wild-type spores. These DPA-less spores did not germinate spontaneously, as DPA-less B. subtilis spores do. Indeed, wild-type and spoVA C. perfringens spores germinated similarly with a mixture of l-asparagine and KCl (AK), KCl alone, or a 1:1 chelate of Ca(2+) and DPA (Ca-DPA). However, the viability of C. perfringens spoVA spores was 20-fold lower than the viability of wild-type spores. Decoated wild-type and spoVA spores exhibited little, if any, germination with AK, KCl, or exogenous Ca-DPA, and their colony-forming efficiency was 10(3)- to 10(4)-fold lower than that of intact spores. However, lysozyme treatment rescued these decoated spores. Although the levels of DNA-protective alpha/beta-type, small, acid-soluble spore proteins in spoVA spores were similar to those in wild-type spores, spoVA spores exhibited markedly lower resistance to moist heat, formaldehyde, HCl, hydrogen peroxide, nitrous acid, and UV radiation than wild-type spores did. In sum, these results suggest the following. (i) SpoVA proteins are essential for Ca-DPA uptake by developing spores during C. perfringens sporulation. (ii) SpoVA proteins and Ca-DPA release are not required for C. perfringens spore germination. (iii) A low spore core water content is essential for full resistance of C. perfringens spores to moist heat, UV radiation, and chemicals.
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Cortex peptidoglycan lytic activity in germinating Bacillus anthracis spores. J Bacteriol 2008; 190:4541-8. [PMID: 18456807 DOI: 10.1128/jb.00249-08] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial endospore dormancy and resistance properties depend on the relative dehydration of the spore core, which is maintained by the spore membrane and its surrounding cortex peptidoglycan wall. During spore germination, the cortex peptidoglycan is rapidly hydrolyzed by lytic enzymes packaged into the dormant spore. The peptidoglycan structures in both dormant and germinating Bacillus anthracis Sterne spores were analyzed. The B. anthracis dormant spore peptidoglycan was similar to that found in other species. During germination, B. anthracis released peptidoglycan fragments into the surrounding medium more quickly than some other species. A major lytic enzymatic activity was a glucosaminidase, probably YaaH, that cleaved between N-acetylglucosamine and muramic-delta-lactam. An epimerase activity previously proposed to function on spore peptidoglycan was not detected, and it is proposed that glucosaminidase products were previously misidentified as epimerase products. Spore cortex lytic enzymes and their regulators are attractive targets for development of germination inhibitors to kill spores and for development of activators to cause loss of resistance properties for decontamination of spore release sites.
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Kumazawa T, Masayama A, Fukuoka S, Makino S, Yoshimura T, Moriyama R. Mode of action of a germination-specific cortex-lytic enzyme, SleC, of Clostridium perfringens S40. Biosci Biotechnol Biochem 2007; 71:884-92. [PMID: 17420590 DOI: 10.1271/bbb.60511] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hydrolysis of the bacterial spore peptidoglycan (cortex) is a crucial event in spore germination. It has been suggested that SleC and SleM, which are conserved among clostridia, are to be considered putative cortex-lytic enzymes in Clostridium perfringens. However, little is known about the details of the hydrolytic process by these enzymes during germination, except that SleM functions as a muramidase. Muropeptides derived from SleC-digested decoated spores of a Bacillus subtilis mutant that lacks the enzymes, SleB, YaaH and CwlJ, related to cortex hydrolysis were identified by amino acid analysis and mass spectrometry. The results suggest that SleC is most likely a bifunctional enzyme possessing lytic transglycosylase activity and N-acetylmuramoyl-L-alanine amidase activity confined to cross-linked tetrapeptide-tetrapeptide moieties of the cortex structure. Furthermore, it appears that during germination of Clostridium perfringens spores, SleC causes merely small and local changes in the cortex structure, which are necessary before SleM can function.
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Affiliation(s)
- Toshihiko Kumazawa
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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26
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Masayama A, Hamasaki K, Urakami K, Shimamoto S, Kato S, Makino S, Yoshimura T, Moriyama M, Moriyama R. Expression of germination-related enzymes, CspA, CspB, CspC, SleC, and SleM, of Clostridium perfringens S40 in the mother cell compartment of sporulating cells. Genes Genet Syst 2007; 81:227-34. [PMID: 17038794 DOI: 10.1266/ggs.81.227] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In Clostridium perfringens S40, spore germination-specific enzymes are synthesized during sporulation. Previous reports have demonstrated that two cortex-lytic enzymes, SleC and SleM, and a component of germination-specific protease, CspC, are located outside the cortex as an integral part of the dormant spore. In the present study, we examined the time and compartment of these enzymes' gene expression using reverse transcription-PCR (RT-PCR) and fluorescence microscopy on green fluorescence protein (GFP)-fused proteins. These results suggested that CspABC, SleC, and SleM are synthesized in the mother cell compartment of sporulating cells, probably at stages II approximately III of sporulation, and that the expression of cspABC genes is tricistronic.
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Affiliation(s)
- Atsushi Masayama
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, Japan
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Eckert C, Magnet S, Mesnage S. The Enterococcus hirae Mur-2 enzyme displays N-acetylglucosaminidase activity. FEBS Lett 2007; 581:693-6. [PMID: 17258207 PMCID: PMC1965491 DOI: 10.1016/j.febslet.2007.01.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 01/09/2007] [Accepted: 01/12/2007] [Indexed: 11/21/2022]
Abstract
Enterococcus hirae produces two autolytic enzymes named Mur-1 and Mur-2, both previously described as N-acetylmuramidases. We used tandem mass spectrometry to show that Mur-2 in fact displays N-acetylglucosaminidase activity. This result reveals that Mur-2 and its counterparts studied to date, which are members of glycosyl hydrolase family 73 from the CAZy (Carbohydrate-Active enZyme) database, display the same catalytic activity.
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Affiliation(s)
- Catherine Eckert
- Structures Bacteriennes Impliquees Dans la Modulation de la Resistance Aux Antibiotiques
INSERM : U655 IFR58Université Pierre et Marie Curie - Paris VIInstitut Biomedical Des Cordeliers
15, Rue de L'Ecole de Medecine
75270 PARIS CEDEX 06,FR
- Faculté de Médecine
Université René Descartes - Paris VParis,FR
- AP-HP
Hôpital européen Georges PompidouFR
| | - Sophie Magnet
- Structures Bacteriennes Impliquees Dans la Modulation de la Resistance Aux Antibiotiques
INSERM : U655 IFR58Université Pierre et Marie Curie - Paris VIInstitut Biomedical Des Cordeliers
15, Rue de L'Ecole de Medecine
75270 PARIS CEDEX 06,FR
- Faculté de Médecine
Université René Descartes - Paris VParis,FR
| | - Stéphane Mesnage
- Structures Bacteriennes Impliquees Dans la Modulation de la Resistance Aux Antibiotiques
INSERM : U655 IFR58Université Pierre et Marie Curie - Paris VIInstitut Biomedical Des Cordeliers
15, Rue de L'Ecole de Medecine
75270 PARIS CEDEX 06,FR
- Faculté de Médecine
Université René Descartes - Paris VParis,FR
- * Correspondence should be adressed to: Stéphane Mesnage
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Dhalluin A, Bourgeois I, Pestel-Caron M, Camiade E, Raux G, Courtin P, Chapot-Chartier MP, Pons JL. Acd, a peptidoglycan hydrolase of Clostridium difficile with N-acetylglucosaminidase activity. Microbiology (Reading) 2005; 151:2343-2351. [PMID: 16000724 DOI: 10.1099/mic.0.27878-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A gene encoding a putative peptidoglycan hydrolase was identified by sequence similarity searching in the Clostridium difficile 630 genome sequence, and the corresponding protein, named Acd (autolysin of C. difficile) was expressed in Escherichia coli. The deduced amino acid sequence of Acd shows a modular structure with two main domains: an N-terminal domain exhibiting repeated sequences and a C-terminal catalytic domain. The C-terminal domain exhibits sequence similarity with the glucosaminidase domains of Staphylococcus aureus Atl and Bacillus subtilis LytD autolysins. Purified recombinant Acd produced in E. coli was confirmed to be a cell-wall hydrolase with lytic activity on the peptidoglycan of several Gram-positive bacteria, including C. difficile. The hydrolytic specificity of Acd was studied by RP-HPLC analysis and MALDI-TOF MS using B. subtilis cell-wall extracts. Muropeptides generated by Acd hydrolysis demonstrated that Acd hydrolyses peptidoglycan bonds between N-acetylglucosamine and N-acetylmuramic acid, confirming that Acd is an N-acetylglucosaminidase. The transcription of the acd gene increased during vegetative cellular growth of C. difficile 630. The sequence of the acd gene appears highly conserved in C. difficile strains. Regarding deduced amino acid sequences, the C-terminal domain with enzymic function appears to be the most conserved of the two main domains. Acd is the first known autolysin involved in peptidoglycan hydrolysis of C. difficile.
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Affiliation(s)
- Anne Dhalluin
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Ingrid Bourgeois
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Martine Pestel-Caron
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Emilie Camiade
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Gregory Raux
- INSERM U 614 (IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 76183 Rouen Cedex, France
| | - Pascal Courtin
- Unité de Biochimie et Structure des Protéines, INRA, 78352 Jouy-en-Josas Cedex, France
| | | | - Jean-Louis Pons
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
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30
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Gilmore ME, Bandyopadhyay D, Dean AM, Linnstaedt SD, Popham DL. Production of muramic delta-lactam in Bacillus subtilis spore peptidoglycan. J Bacteriol 2004; 186:80-9. [PMID: 14679227 PMCID: PMC303458 DOI: 10.1128/jb.186.1.80-89.2004] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial spore heat resistance is primarily dependent upon dehydration of the spore cytoplasm, a state that is maintained by the spore peptidoglycan wall, the spore cortex. A peptidoglycan structural modification found uniquely in spores is the formation of muramic delta-lactam. Production of muramic delta-lactam in Bacillus subtilis requires removal of a peptide side chain from the N-acetylmuramic acid residue by a cwlD-encoded muramoyl-L-Alanine amidase. Expression of cwlD takes place in both the mother cell and forespore compartments of sporulating cells, though expression is expected to be required only in the mother cell, from which cortex synthesis derives. Expression of cwlD in the forespore is in a bicistronic message with the upstream gene ybaK. We show that ybaK plays no apparent role in spore peptidoglycan synthesis and that expression of cwlD in the forespore plays no significant role in spore peptidoglycan formation. Peptide cleavage by CwlD is apparently followed by deacetylation of muramic acid and lactam ring formation. The product of pdaA (yfjS), which encodes a putative deacetylase, has recently been shown to also be required for muramic delta-lactam formation. Expression of CwlD in Escherichia coli results in muramoyl L-Alanine amidase activity but no muramic delta-lactam formation. Expression of PdaA alone in E. coli had no effect on E. coli peptidoglycan structure, whereas expression of CwlD and PdaA together resulted in the formation of muramic delta-lactam. CwlD and PdaA are necessary and sufficient for muramic delta-lactam production, and no other B. subtilis gene product is required. PdaA probably carries out both deacetylation and lactam ring formation and requires the product of CwlD activity as a substrate.
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Affiliation(s)
- Meghan E Gilmore
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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31
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Affiliation(s)
- Ynte P. de Vries
- Wageningen Centre for Food Sciences
- Wageningen UR Laboratory of Food Microbiology
- Agrotechnology and Food Innovations A&F
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32
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33
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Atrih A, Foster SJ. In vivo roles of the germination-specific lytic enzymes of Bacillus subtilis 168. MICROBIOLOGY (READING, ENGLAND) 2001; 147:2925-32. [PMID: 11700343 DOI: 10.1099/00221287-147-11-2925] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Germination of endospores of Bacillus subtilis involves the activities of several germination-specific lytic enzymes, including glucosaminidase and lytic transglycosylase. Another non-hydrolytic activity, likely to be due to an epimerase, also occurs. The effect of pH on enzyme activities and the overall germination rate was measured. Optimal germination occurred between pH 7-9; however, optimum glucosaminidase and epimerase activities were noted at pH 5. Conversely, the lytic transglycosylase activity was greatest at pH 8. Treatment of spores (15 min) with heat (90 degrees C) or NaOH (0.25 M) led to impaired cortex hydrolysis/modification, but with <20% loss in viability. Analysis of muropeptides in the germination exudate revealed a reduction of >85% in glucosaminidase and epimerase products, when compared to untreated spores. Conversely, lytic transglycosylase activity was increased by alkali or heat treatment, which was possibly due to increased substrate availability. FB101 (sleB) spores, which lack lytic transglycosylase activity, showed 90-fold greater loss in viability than the wild-type after 1 h at 90 degrees C. Similarly, 97% of FB101 (sleB) spores were unable to form a colony on nutrient agar after 130 min exposure to 0.25 M NaOH at 4 degrees C, whereas the wild-type was unaffected. This demonstrates the crucial role of the lytic transglycosylase in cortex hydrolysis of damaged spores. The respective targets of heat and alkali in spores and their role during germination are discussed.
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Affiliation(s)
- A Atrih
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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34
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Shimamoto S, Moriyama R, Sugimoto K, Miyata S, Makino S. Partial characterization of an enzyme fraction with protease activity which converts the spore peptidoglycan hydrolase (SleC) precursor to an active enzyme during germination of Clostridium perfringens S40 spores and analysis of a gene cluster involved in the activity. J Bacteriol 2001; 183:3742-51. [PMID: 11371539 PMCID: PMC95252 DOI: 10.1128/jb.183.12.3742-3751.2001] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A spore cortex-lytic enzyme of Clostridium perfringens S40 which is encoded by sleC is synthesized at an early stage of sporulation as a precursor consisting of four domains. After cleavage of an N-terminal presequence and a C-terminal prosequence during spore maturation, inactive proenzyme is converted to active enzyme by processing of an N-terminal prosequence with germination-specific protease (GSP) during germination. The present study was undertaken to characterize GSP. In the presence of 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS), a nondenaturing detergent which was needed for the stabilization of GSP, GSP activity was extracted from germinated spores. The enzyme fraction, which was purified to 668-fold by column chromatography, contained three protein components with molecular masses of 60, 57, and 52 kDa. The protease showed optimum activity at pH 5.8 to 8.5 in the presence of 0.1% CHAPS and retained activity after heat treatment at 55 degrees C for 40 min. GSP specifically cleaved the peptide bond between Val-149 and Val-150 of SleC to generate mature enzyme. Inactivation of GSP by phenylmethylsulfonyl fluoride and HgCl(2) indicated that the protease is a cysteine-dependent serine protease. Several pieces of evidence demonstrated that three protein components of the enzyme fraction are processed forms of products of cspA, cspB, and cspC, which are positioned in a tandem array just upstream of the 5' end of sleC. The amino acid sequences deduced from the nucleotide sequences of the csp genes showed significant similarity and showed a high degree of homology with those of the catalytic domain and the oxyanion binding region of subtilisin-like serine proteases. Immunochemical studies suggested that active GSP likely is localized with major cortex-lytic enzymes on the exterior of the cortex layer in the dormant spore, a location relevant to the pursuit of a cascade of cortex hydrolytic reactions.
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Affiliation(s)
- S Shimamoto
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
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35
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Meador-Parton J, Popham DL. Structural analysis of Bacillus subtilis spore peptidoglycan during sporulation. J Bacteriol 2000; 182:4491-9. [PMID: 10913082 PMCID: PMC94620 DOI: 10.1128/jb.182.16.4491-4499.2000] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major structural element of bacterial endospores is a peptidoglycan (PG) wall. This wall is produced between the two opposed membranes surrounding the developing forespore and is composed of two layers. The inner layer is the germ cell wall, which appears to have a structure similar to that of the vegetative cell wall and which serves as the initial cell wall following spore germination. The outer layer, the cortex, has a modified structure, is required for maintenance of spore dehydration, and is degraded during spore germination. Theories suggest that the spore PG may also play a mechanical role in the attainment of spore dehydration. Inherent in one of these models is the production of a gradient of cross-linking across the span of the spore PG. We report analyses of the structure of PG found within immature, developing Bacillus subtilis forespores. The germ cell wall PG is synthesized first, followed by the cortex PG. The germ cell wall is relatively highly cross-linked. The degree of PG cross-linking drops rapidly during synthesis of the first layers of cortex PG and then increases two- to eightfold across the span of the outer 70% of the cortex. Analyses of forespore PG synthesis in mutant strains reveal that some strains that lack this gradient of cross-linking are able to achieve normal spore core dehydration. We conclude that spore PG with cross-linking within a broad range is able to maintain, and possibly to participate in, spore core dehydration. Our data indicate that the degree of spore PG cross-linking may have a more direct impact on the rate of spore germination and outgrowth.
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Affiliation(s)
- J Meador-Parton
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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36
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Okamura S, Urakami K, Kimata M, Aoshima T, Shimamoto S, Moriyama R, Makino S. The N-terminal prepeptide is required for the production of spore cortex-lytic enzyme from its inactive precursor during germination of Clostridium perfringens S40 spores. Mol Microbiol 2000; 37:821-7. [PMID: 10972804 DOI: 10.1046/j.1365-2958.2000.02047.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A spore cortex-lytic enzyme of Clostridium perfringens S40 is synthesized during sporulation as a precursor consisting of four domains. After cleavage of an N-terminal preregion and a C-terminal proregion, inactive proenzyme (termed C35) is converted to active enzyme by processing of an N-terminal prosequence with germination-specific protease (GSP) during germination. The present results demonstrated that the cleaved N-terminal prepeptide remained associated with C35. After the isolated complex was denatured and dissociated in 6 M urea solution, removal of urea regenerated a prepeptide-C35 complex which produces active enzyme when incubated with GSP. However, isolated C35 alone could not be activated by GSP. The prepeptide-C35 complex was more heat stable than active enzyme. Thus, non-covalent attachment of the prepeptide to C35 is required to assist correct folding of C35 and to stabilize its conformation, suggesting that the prepeptide functions as an intramolecular chaperone. Recombinant proteins, which have prepeptide covalently bonded to C35, were processed by GSP as well as the in vivo prepeptide-C35 complex, and the full length of the N-terminal presequence was needed to fulfil its role. Although the C-terminal prosequence is present as an independent domain which is not involved in the activation process of the enzyme, it appears that the N-terminal prosequence contributes to the regulation of enzyme activity as an inhibitor of the enzyme.
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Affiliation(s)
- S Okamura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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37
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Chen Y, Fukuoka S, Makino S. A novel spore peptidoglycan hydrolase of Bacillus cereus: biochemical characterization and nucleotide sequence of the corresponding gene, sleL. J Bacteriol 2000; 182:1499-506. [PMID: 10692353 PMCID: PMC94445 DOI: 10.1128/jb.182.6.1499-1506.2000] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The exudate of germinated spores of B. cereus IFO 13597 in 0.15 M KCl-50 mM potassium phosphate (pH 7.0) contained a spore-lytic enzyme which has substrate specificity for fragmented spore cortex from wild-type organisms (cortical-fragment-lytic enzyme [CFLE]), in addition to a previously characterized germination-specific hydrolase which acts on intact spore cortex (spore cortex-lytic enzyme [SCLE]) (R. Moriyama, S. Kudoh, S. Miyata, S. Nonobe, A. Hattori, and S. Makino, J. Bacteriol. 178:5330-5332, 1996). CFLE was not capable of degrading isolated cortical fragments from spores of Bacillus subtilis ADD1, which lacks muramic acid delta-lactam. This suggests that CFLE cooperates with SCLE in cortex hydrolysis during germination. CFLE was purified in an active form and identified as a 48-kDa protein which functions as an N-acetylglucosaminidase. Immunochemical studies suggested that the mature enzyme is localized on a rather peripheral region of the dormant spore, probably the exterior of the cortex layer. A gene encoding the enzyme, sleL, was cloned in Escherichia coli, and the nucleotide sequence was determined. The gene encodes a protein of 430 amino acids with a deduced molecular weight of 48,136. The N-terminal region contains a repeated motif common to several peptidoglycan binding proteins. Inspection of the data banks showed no similarity of CFLE with N-acetylglucosaminidases found so far, suggesting that CFLE is a novel type of N-acetylglucosaminidase. The B. subtilis genome sequence contains genes, yaaH and ydhD, which encode putative proteins showing similarity to SleL.
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Affiliation(s)
- Y Chen
- Department of Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
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38
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Smith TJ, Blackman SA, Foster SJ. Autolysins of Bacillus subtilis: multiple enzymes with multiple functions. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 2):249-262. [PMID: 10708363 DOI: 10.1099/00221287-146-2-249] [Citation(s) in RCA: 314] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Thomas J Smith
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
| | - Steve A Blackman
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
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39
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Boland FM, Atrih A, Chirakkal H, Foster SJ, Moir A. Complete spore-cortex hydrolysis during germination of Bacillus subtilis 168 requires SleB and YpeB. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 1):57-64. [PMID: 10658652 DOI: 10.1099/00221287-146-1-57] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The role of the sleB gene of Bacillus subtilis, which encodes a putative spore-cortex-lytic enzyme, and the downstream ypeB gene were investigated. Both SleB and YpeB were required for normal germination to occur. The corresponding mutants formed phase-bright, heat-resistant spores with no apparent defects in dormancy. However, mutant spore suspensions lost optical density slower than the wild-type and spores were phase-grey even 12 h after the triggering of germination. Since the loss of heat resistance and release of dipicolinic acid was similar to the wild-type, these mutants were blocked in the later stages of germination. The mutants were nevertheless capable of outgrowth on rich agar to form colonies, indicating that other spore components can compensate for their function sufficiently to allow outgrowth. The expression and regulation of the operon was examined using a lacZ transcriptional fusion. Expression of the operon began 2 h after the onset of sporulation and was under the control of RNA polymerase containing the forespore-specific sigma factor, sigmaG. The application of reverse phase HPLC revealed that the mutants do not have any structural defect in the dormant spore cortex and therefore these genes are not required for normal spore-cortex synthesis. The analysis of peptidoglycan dynamics during germination showed, however, that the cortex was only partially hydrolysed in both mutants. This analysis also revealed that the likely hydrolytic bond specificity of SleB is likely to be that of a lytic transglycosylase.
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Affiliation(s)
- Fiona M Boland
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
| | - Abdelmadjid Atrih
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
| | - Haridasan Chirakkal
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
| | - Anne Moir
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK1
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40
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Urakami K, Miyata S, Moriyama R, Sugimoto K, Makino S. Germination-specific cortex-lytic enzymes from Clostridium perfringens S40 spores: time of synthesis, precursor structure and regulation of enzymatic activity. FEMS Microbiol Lett 1999; 173:467-73. [PMID: 10227176 DOI: 10.1111/j.1574-6968.1999.tb13540.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Germination-specific enzymes, an amidase and a muramidase, of Clostridium perfringens S40 were synthesized at the time of forespore formation during sporulation. The amidase had a unique precursor structure consisting of four domains: the N-terminal pre-sequence, the N-terminal pro-sequence, mature enzyme and the C-terminal pro-sequence. The N-terminal pre-sequence and the C-terminal pro-sequence were sequentially processed at the time of development of phase-bright spores, and the resulting inactive pro-enzyme was activated by cleavage of the N-terminal pro-sequence with a specific protease during germination. A possible mechanism for the regulation of activity of muramidase, which is produced as a mature form and does not need processing for activation, is presented.
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Affiliation(s)
- K Urakami
- Department of Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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41
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Moriyama R, Fukuoka H, Miyata S, Kudoh S, Hattori A, Kozuka S, Yasuda Y, Tochikubo K, Makino S. Expression of a germination-specific amidase, SleB, of Bacilli in the forespore compartment of sporulating cells and its localization on the exterior side of the cortex in dormant spores. J Bacteriol 1999; 181:2373-8. [PMID: 10197998 PMCID: PMC93660 DOI: 10.1128/jb.181.8.2373-2378.1999] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A germination-specific amidase of bacilli is a major spore-lytic enzyme that is synthesized with a putative signal sequence and hydrolyses spore cortex in situ. The sleB gene encoding this amidase in Bacillus subtilis and Bacillus cereus was expressed in the forespore compartment of sporulating cells under the control of sigmaG, as shown by Northern blot and primer extension analyses. The forespore-specific expression of B. subtilis sleB was further indicated by the forespore-specific accumulation of a SleB-green fluorescent protein fusion protein from which a putative secretion signal of SleB was deleted. Immunoelectron microscopy with anti-SleB antiserum and a colloidal gold-immunoglobulin G complex showed that the enzymes from both Bacillus species are located just inside the spore coat layer in the dormant spore, and in the dormant spore, the amidases appear exist in a mature form lacking a signal sequence. These results indicate that SleB is translocated across the forespore's inner membrane by a secretion signal peptide and is deposited in cortex layer synthesized between the forespore inner and outer membranes. The peripheral location of the spore-lytic enzymes in the dormant spore suggests that spore germination is initiated at the exterior of the cortex.
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Affiliation(s)
- R Moriyama
- Department of Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
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42
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Atrih A, Zöllner P, Allmaier G, Williamson MP, Foster SJ. Peptidoglycan structural dynamics during germination of Bacillus subtilis 168 endospores. J Bacteriol 1998; 180:4603-12. [PMID: 9721302 PMCID: PMC107474 DOI: 10.1128/jb.180.17.4603-4612.1998] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/1998] [Accepted: 06/17/1998] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycan structural dynamics during endospore germination of Bacillus subtilis 168 have been examined by muropeptide analysis. The first germination-associated peptidoglycan structural changes are detected within 3 min after the addition of the specific germinant L-alanine. We detected in the spore-associated material new muropeptides which, although they have slightly longer retention times by reversed-phase (RP)-high-pressure liquid chromatography (HPLC) than related ones in dormant spores, show the same amino acid composition and molecular mass. Two-dimensional nuclear magnetic resonance (NMR) analysis shows that the chemical changes to the muropeptides on germination are minor and are probably limited to stereochemical inversion. These new muropeptides account for almost 26% of the total muropeptides in spore-associated material after 2 h of germination. The exudate of germinated spores of B. subtilis 168 contains novel muropeptides in addition to those present in spore-associated material. Exudate-specific muropeptides have longer retention times, have no reducing termini, and exhibit a molecular mass 20 Da lower than those of related reduced muropeptides. These new products are anhydro-muropeptides which are generated by a lytic transglycosylase, the first to be identified in a gram-positive bacterium. There is also evidence for the activity of a glucosaminidase during the germination process. Quantification of muropeptides in spore-associated material indicates that there is a heterogeneous distribution of muropeptides in spore peptidoglycan. The spore-specific residue, muramic delta-lactam, is proposed to be a major substrate specificity determinant of germination-specific lytic enzymes, allowing cortex hydrolysis without any effect on the primordial cell wall.
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Affiliation(s)
- A Atrih
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
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43
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Ishikawa S, Yamane K, Sekiguchi J. Regulation and characterization of a newly deduced cell wall hydrolase gene (cwlJ) which affects germination of Bacillus subtilis spores. J Bacteriol 1998; 180:1375-80. [PMID: 9515903 PMCID: PMC107033 DOI: 10.1128/jb.180.6.1375-1380.1998] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The predicted amino acid sequence of Bacillus subtilis ycbQ (renamed cwlJ) exhibits high similarity to those of the deduced C-terminal catalytic domain of SleBs, the specific cortex-hydrolyzing enzyme of B. cereus and the deduced one of B. subtilis. We constructed a cwlJ::lacZ fusion in the B. subtilis chromosome. The beta-galactosidase activity and results of Northern hybridization and primer extension analyses of the cwlJ gene indicated that it is transcribed by EsigmaE RNA polymerase. cwlJ-deficient spores responded to both L-alanine and AGFK, the A580 values of spore suspensions decreased more slowly than in the case of the wild-type strain, and the mutant spores released less dipicolinic acid than did those of the wild-type strain during germination. However, the mutant spores released only slightly less hexosamine than did the wild-type spores. In contrast, B. subtilis sleB spores did not release hexosamine at a significant level. While cwlJ and sleB spores were able to germinate, CJSB (cwlJ sleB) spores could not germinate but exhibited initial germination reactions, e.g., partial decrease in A580 and slow release of dipicolinic acid. CJSB spores became slightly gray after 6 h in the germinant, but their refractility was much greater than that of sleB mutant spores. The roles of the sleB and cwlJ mutations in germination and spore maturation are also discussed.
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MESH Headings
- Alanine/pharmacology
- Amino Acid Sequence
- Bacillus cereus/genetics
- Bacillus subtilis/enzymology
- Bacillus subtilis/genetics
- Bacillus subtilis/physiology
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Base Sequence
- Chromosomes, Bacterial
- Cloning, Molecular
- DNA, Bacterial/analysis
- DNA, Bacterial/genetics
- Gene Expression Regulation, Bacterial
- Gene Expression Regulation, Enzymologic
- Hexosamines/metabolism
- Hydrolases/genetics
- Hydrolases/metabolism
- Lac Operon
- Molecular Sequence Data
- Picolinic Acids/metabolism
- Plasmids
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Recombination, Genetic
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Spores, Bacterial/enzymology
- Spores, Bacterial/genetics
- Spores, Bacterial/physiology
- Transcription, Genetic
- Transformation, Genetic
- beta-Galactosidase/metabolism
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Affiliation(s)
- S Ishikawa
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
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