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Luo H, Qu X, Deng X, He L, Wu Y, Liu Y, He D, Yin J, Wang B, Gan F, Tang B, Tang XF. HtrAs are essential for the survival of the haloarchaeon Natrinema gari J7-2 in response to heat, high salinity, and toxic substances. Appl Environ Microbiol 2024; 90:e0204823. [PMID: 38289131 PMCID: PMC10880668 DOI: 10.1128/aem.02048-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/24/2023] [Indexed: 02/22/2024] Open
Abstract
Bacterial and eukaryotic HtrAs can act as an extracytoplasmic protein quality control (PQC) system to help cells survive in stress conditions, but the functions of archaeal HtrAs remain unknown. Particularly, haloarchaea route most secretory proteins to the Tat pathway, enabling them to fold properly in well-controlled cytoplasm with cytosolic PQC systems before secretion. It is unclear whether HtrAs are required for haloarchaeal survival and stress response. The haloarchaeon Natrinema gari J7-2 encodes three Tat signal peptide-bearing HtrAs (NgHtrA, NgHtrB, and NgHtrC), and the signal peptides of NgHtrA and NgHtrC contain a lipobox. Here, the in vitro analysis reveals that the three HtrAs show different profiles of temperature-, salinity-, and metal ion-dependent proteolytic activities and could exhibit chaperone-like activities to prevent the aggregation of reduced lysozyme when their proteolytic activities are inhibited at low temperatures or the active site is disrupted. The gene deletion and complementation assays reveal that NgHtrA and NgHtrC are essential for the survival of strain J7-2 at elevated temperature and/or high salinity and contribute to the resistance of this haloarchaeon to zinc and inhibitory substances generated from tryptone. Mutational analysis shows that the lipobox mediates membrane anchoring of NgHtrA or NgHtrC, and both the membrane-anchored and free extracellular forms of the two enzymes are involved in the stress resistance of strain J7-2, depending on the stress conditions. Deletion of the gene encoding NgHtrB in strain J7-2 causes no obvious growth defect, but NgHtrB can functionally substitute for NgHtrA or NgHtrC under some conditions.IMPORTANCEHtrA-mediated protein quality control plays an important role in the removal of aberrant proteins in the extracytoplasmic space of living cells, and the action mechanisms of HtrAs have been extensively studied in bacteria and eukaryotes; however, information about the function of archaeal HtrAs is scarce. Our results demonstrate that three HtrAs of the haloarchaeon Natrinema gari J7-2 possess both proteolytic and chaperone-like activities, confirming that the bifunctional nature of HtrAs is conserved across all three domains of life. Moreover, we found that NgHtrA and NgHtrC are essential for the survival of strain J7-2 under stress conditions, while NgHtrB can serve as a substitute for the other two HtrAs under certain circumstances. This study provides the first biochemical and genetic evidence of the importance of HtrAs for the survival of haloarchaea in response to stresses.
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Affiliation(s)
- Hongyi Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaoyi Qu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xi Deng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Liping He
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yi Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yang Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Dan He
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jing Yin
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Bingxue Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Fei Gan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education and Hubei Province, Wuhan, China
| | - Bing Tang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education and Hubei Province, Wuhan, China
| | - Xiao-Feng Tang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
- Cooperative Innovation Center of Industrial Fermentation, Ministry of Education and Hubei Province, Wuhan, China
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Lenoir C, Pelletier A, Manuse S, Millat H, Ducret A, Galinier A, Doan T, Grangeasse C. The morphogenic protein CopD controls the spatio-temporal dynamics of PBP1a and PBP2b in Streptococcus pneumoniae. mBio 2023; 14:e0141123. [PMID: 37728370 PMCID: PMC10653890 DOI: 10.1128/mbio.01411-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/25/2023] [Indexed: 09/21/2023] Open
Abstract
IMPORTANCE Penicillin-binding proteins (PBPs) are essential for proper bacterial cell division and morphogenesis. The genome of Streptococcus pneumoniae encodes for two class B PBPs (PBP2x and 2b), which are required for the assembly of the peptidoglycan framework and three class A PBPs (PBP1a, 1b and 2a), which remodel the peptidoglycan mesh during cell division. Therefore, their activities should be finely regulated in space and time to generate the pneumococcal ovoid cell shape. To date, two proteins, CozE and MacP, are known to regulate the function of PBP1a and PBP2a, respectively. In this study, we describe a novel regulator (CopD) that acts on both PBP1a and PBP2b. These findings provide valuable information for understanding bacterial cell division. Furthermore, knowing that ß-lactam antibiotic resistance often arises from PBP mutations, the characterization of such a regulator represents a promising opportunity to develop new strategies to resensitize resistant strains.
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Affiliation(s)
- Cassandra Lenoir
- Molecular Microbiology and Structural Biochemistry, UMR, Université de Lyon, CNRS, Lyon, France
| | - Anaïs Pelletier
- Molecular Microbiology and Structural Biochemistry, UMR, Université de Lyon, CNRS, Lyon, France
| | - Sylvie Manuse
- Molecular Microbiology and Structural Biochemistry, UMR, Université de Lyon, CNRS, Lyon, France
| | - Hugo Millat
- Molecular Microbiology and Structural Biochemistry, UMR, Université de Lyon, CNRS, Lyon, France
| | - Adrien Ducret
- Molecular Microbiology and Structural Biochemistry, UMR, Université de Lyon, CNRS, Lyon, France
| | - Anne Galinier
- Laboratoire de Chimie Bactérienne, UMR, Aix-Marseille Université, CNRS, Marseille, France
| | - Thierry Doan
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UMR, Aix-Marseille Université, Marseille, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, UMR, Université de Lyon, CNRS, Lyon, France
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The Membrane Proteome of Spores and Vegetative Cells of the Food-Borne Pathogen Bacillus cereus. Int J Mol Sci 2021; 22:ijms222212475. [PMID: 34830357 PMCID: PMC8624511 DOI: 10.3390/ijms222212475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
Membrane proteins are fascinating since they play an important role in diverse cellular functions and constitute many drug targets. Membrane proteins are challenging to analyze. The spore, the most resistant form of known life, harbors a compressed inner membrane. This membrane acts not only as a barrier for undesired molecules but also as a scaffold for proteins involved in signal transduction and the transport of metabolites during spore germination and subsequent vegetative growth. In this study, we adapted a membrane enrichment method to study the membrane proteome of spores and cells of the food-borne pathogen Bacillus cereus using quantitative proteomics. Using bioinformatics filtering we identify and quantify 498 vegetative cell membrane proteins and 244 spore inner membrane proteins. Comparison of vegetative and spore membrane proteins showed there were 54 spore membrane-specific and 308 cell membrane-specific proteins. Functional characterization of these proteins showed that the cell membrane proteome has a far larger number of transporters, receptors and proteins related to cell division and motility. This was also reflected in the much higher expression level of many of these proteins in the cellular membrane for those proteins that were in common with the spore inner membrane. The spore inner membrane had specific expression of several germinant receptors and spore-specific proteins, but also seemed to show a preference towards the use of simple carbohydrates like glucose and fructose owing to only expressing transporters for these. These results show the differences in membrane proteome composition and show us the specific proteins necessary in the inner membrane of a dormant spore of this toxigenic spore-forming bacterium to survive adverse conditions.
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Delisle J, Cordier B, Audebert S, Pophillat M, Cluzel C, Espinosa L, Grangeasse C, Galinier A, Doan T. Characterization of TseB: A new actor in cell wall elongation in Bacillus subtilis. Mol Microbiol 2021; 116:1099-1112. [PMID: 34411374 DOI: 10.1111/mmi.14798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 08/16/2021] [Accepted: 08/16/2021] [Indexed: 11/30/2022]
Abstract
Penicillin-binding proteins (PBPs) are crucial enzymes of peptidoglycan assembly and targets of β-lactam antibiotics. However, little is known about their regulation. Recently, membrane proteins were shown to regulate the bifunctional transpeptidases/glycosyltransferases aPBPs in some bacteria. However, up to now, regulators of monofunctional transpeptidases bPBPs have yet to be revealed. Here, we propose that TseB could be such a PBP regulator. This membrane protein was previously found to suppress tetracycline sensitivity of a Bacillus subtilis strain deleted for ezrA, a gene encoding a regulator of septation ring formation. In this study, we show that TseB is required for B. subtilis normal cell shape, tseB mutant cells being shorter and wider than wild-type cells. We observed that TseB interacts with PBP2A, a monofunctional transpeptidase. While TseB is not required for PBP2A activity, stability, and localization, we show that the overproduction of PBP2A is deleterious in the absence of TseB. In addition, we showed that TseB is necessary not only for efficient cell wall elongation during exponential phase but also during spore outgrowth, as it was also observed for PBP2A. Altogether, our results suggest that TseB is a new member of the elongasome that regulates PBP2A function during cell elongation and spore germination.
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Affiliation(s)
- Jordan Delisle
- Laboratoire de Chimie Bactérienne, UMR 7283, CNRS/Aix-Marseille Univ, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Baptiste Cordier
- Laboratoire de Chimie Bactérienne, UMR 7283, CNRS/Aix-Marseille Univ, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Stéphane Audebert
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille Protéomique, Marseille, France
| | - Matthieu Pophillat
- Aix-Marseille Univ, INSERM, CNRS, Institut Paoli-Calmettes, CRCM, Marseille Protéomique, Marseille, France
| | - Caroline Cluzel
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique, UMR 5305, CNRS/Université Lyon I, Lyon, France
| | - Leon Espinosa
- Laboratoire de Chimie Bactérienne, UMR 7283, CNRS/Aix-Marseille Univ, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, UMR 5086, CNRS/Université Lyon I, Lyon, France
| | - Anne Galinier
- Laboratoire de Chimie Bactérienne, UMR 7283, CNRS/Aix-Marseille Univ, Institut de Microbiologie de la Méditerranée, Marseille, France
| | - Thierry Doan
- Laboratoire de Chimie Bactérienne, UMR 7283, CNRS/Aix-Marseille Univ, Institut de Microbiologie de la Méditerranée, Marseille, France
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Harwood CR, Kikuchi Y. The ins and outs of Bacillus proteases: activities, functions and commercial significance. FEMS Microbiol Rev 2021; 46:6354784. [PMID: 34410368 PMCID: PMC8767453 DOI: 10.1093/femsre/fuab046] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/17/2021] [Indexed: 12/23/2022] Open
Abstract
Because the majority of bacterial species divide by binary fission, and do not have distinguishable somatic and germline cells, they could be considered to be immortal. However, bacteria ‘age’ due to damage to vital cell components such as DNA and proteins. DNA damage can often be repaired using efficient DNA repair mechanisms. However, many proteins have a functional ‘shelf life’; some are short lived, while others are relatively stable. Specific degradation processes are built into the life span of proteins whose activities are required to fulfil a specific function during a prescribed period of time (e.g. cell cycle, differentiation process, stress response). In addition, proteins that are irreparably damaged or that have come to the end of their functional life span need to be removed by quality control proteases. Other proteases are involved in performing a variety of specific functions that can be broadly divided into three categories: processing, regulation and feeding. This review presents a systematic account of the proteases of Bacillus subtilis and their activities. It reviews the proteases found in, or associated with, the cytoplasm, the cell membrane, the cell wall and the external milieu. Where known, the impacts of the deletion of particular proteases are discussed, particularly in relation to industrial applications.
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Affiliation(s)
- Colin R Harwood
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University NE2 4AX, Newcastle upon Tyne, UK
| | - Yoshimi Kikuchi
- Research Institute for Bioscience Products & Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, JAPAN
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Tu Z, Setlow P, Brul S, Kramer G. Molecular Physiological Characterization of a High Heat Resistant Spore Forming Bacillus subtilis Food Isolate. Microorganisms 2021; 9:667. [PMID: 33807113 PMCID: PMC8005191 DOI: 10.3390/microorganisms9030667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/18/2021] [Accepted: 03/20/2021] [Indexed: 02/07/2023] Open
Abstract
Bacterial endospores (spores) are among the most resistant living forms on earth. Spores of Bacillus subtilis A163 show extremely high resistance to wet heat compared to spores of laboratory strains. In this study, we found that spores of B. subtilis A163 were indeed very wet heat resistant and released dipicolinic acid (DPA) very slowly during heat treatment. We also determined the proteome of vegetative cells and spores of B. subtilis A163 and the differences in these proteomes from those of the laboratory strain PY79, spores of which are much less heat resistant. This proteomic characterization identified 2011 proteins in spores and 1901 proteins in vegetative cells of B. subtilis A163. Surprisingly, spore morphogenic protein SpoVM had no homologs in B. subtilis A163. Comparing protein expression between these two strains uncovered 108 proteins that were differentially present in spores and 93 proteins differentially present in cells. In addition, five of the seven proteins on an operon in strain A163, which is thought to be primarily responsible for this strain's spores high heat resistance, were also identified. These findings reveal proteomic differences of the two strains exhibiting different resistance to heat and form a basis for further mechanistic analysis of the high heat resistance of B. subtilis A163 spores.
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Affiliation(s)
- Zhiwei Tu
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UCONN Health, Farmington, CT 06030-3303, USA;
| | - Stanley Brul
- Laboratory for Molecular Biology and Microbial Food Safety, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Gertjan Kramer
- Laboratory for Mass Spectrometry of Biomolecules, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
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Xing Y, Harper WF. Bacillus spore awakening: recent discoveries and technological developments. Curr Opin Biotechnol 2020; 64:110-115. [DOI: 10.1016/j.copbio.2019.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 12/21/2019] [Accepted: 12/23/2019] [Indexed: 12/25/2022]
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Christie G, Setlow P. Bacillus spore germination: Knowns, unknowns and what we need to learn. Cell Signal 2020; 74:109729. [PMID: 32721540 DOI: 10.1016/j.cellsig.2020.109729] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/18/2020] [Accepted: 07/21/2020] [Indexed: 01/06/2023]
Abstract
How might a microbial cell that is entirely metabolically dormant - and which has the ability to remain so for extended periods of time - irreversibly commit itself to resuming vegetative growth within seconds of being exposed to certain amino acids or sugars? That this process takes place in the absence of any detectable ATP or de novo protein synthesis, and relies upon a pre-formed apparatus that is immobilised, respectively, in a semi-crystalline membrane or multi-layered proteinaceous coat, only exacerbates the challenge facing spores of Bacillales species when stimulated to germinate. Whereas the process by which spores are formed in response to nutrient starvation - sporulation - involves the orchestrated interplay between hundreds of distinct proteins, the process by which spores return to life - germination - is a much simpler affair, requiring a handful of receptor and channel proteins complemented with specialized peptidoglycan lysins. Despite this relative simplicity, and research effort spanning many decades, comprehensive understanding of key molecular and biochemical details and, in particular signal transduction mechanisms associated with spore germination, has remained elusive. In this review we provide an up to date overview of the field while identifying what we consider to be the key gaps in knowledge associated with germination of Bacillales spores, suggesting also technical approaches that may provide fresh insight to this unique biological process.
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Affiliation(s)
- Graham Christie
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 OAS, United Kingdom.
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA.
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YpeB dimerization may be required to stabilize SleB for effective germination of Bacillus anthracis spores. BMC Microbiol 2019; 19:169. [PMID: 31349814 PMCID: PMC6660665 DOI: 10.1186/s12866-019-1544-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/18/2019] [Indexed: 12/16/2022] Open
Abstract
Background Bacillus cells faced with unfavorable environmental conditions undergo an asymmetric division process ultimately leading to the formation of the bacterial spore. In some instances the spore serves as an infectious agent; such is the case with the spore of Bacillus anthracis and the disease anthrax. Spores are resistant to a variety of environment conditions including traditional decontamination techniques due to the formation of specialized cellular structures. One such structure, the spore cortex, is a thick layer of modified peptidoglycan that contributes to spore dormancy through maintenance of the dehydrated state of the spore core. During spore germination, degradation of the cortex is required to facilitate complete hydration of the core and a return to vegetative growth. Degradation of the cortex is accomplished through the action of germination-specific lytic enzymes. One of these enzymes, SleB, has been previously shown to require the presence of the YpeB protein for its stable incorporation and subsequent function in spores of B. anthracis. The focus of the present study is to identify protein interactions of YpeB through in vivo chemical cross-linking and two-hybrid analysis. Results Conserved residues within YpeB PepSY domains were altered to facilitate implementation of a site-specific chemical cross-linker, 4-Azidophenacyl bromide. Analyses of crosslinked-spore extracts suggests that YpeB exists as a dimer or larger multimer within the spore, potentially mediated through interactions of the C-terminal domains. Spores expressing stable truncated forms of YpeB were crosslinked and corresponding truncated dimers were detected. Further characterization of individual YpeB domains using bacterial two-hybrid analysis indicated a possible role for both N-and C-terminal domains in YpeB oligomerization. Conclusions The YpeB protein likely exists as dimer or higher-order multimer in the dormant spore. Both the N- and C-terminal YpeB domains contribute to multimerization. SleB likely also exists as an oligomer, and SleB and YpeB may be found together within a protein complex. Disassembly of this complex during spore germination likely allows SleB to become active in spore cortex degradation. Further study of this protein complex may contribute to the development of methods to inhibit or stimulate germination, allowing more effective spore decontamination. Electronic supplementary material The online version of this article (10.1186/s12866-019-1544-1) contains supplementary material, which is available to authorized users.
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Membrane Proteomes and Ion Transporters in Bacillus anthracis and Bacillus subtilis Dormant and Germinating Spores. J Bacteriol 2019; 201:JB.00662-18. [PMID: 30602489 DOI: 10.1128/jb.00662-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 12/17/2018] [Indexed: 12/14/2022] Open
Abstract
Bacterial endospores produced by Bacillus and Clostridium species can remain dormant and highly resistant to environmental insults for long periods, but they can also rapidly germinate in response to a nutrient-rich environment. Multiple proteins involved in sensing and responding to nutrient germinants, initiating solute and water transport, and accomplishing spore wall degradation are associated with the membrane surrounding the spore core. In order to more fully catalog proteins that may be involved in spore germination, as well as to identify protein changes taking place during germination, unbiased proteomic analyses of membrane preparations isolated from dormant and germinated spores of Bacillus anthracis and Bacillus subtilis were undertaken. Membrane-associated proteins were fractionated by SDS-PAGE, gel slices were trypsin digested, and extracted peptides were fractionated by liquid chromatography and analyzed by matrix-assisted laser desorption ionization-tandem time of flight mass spectrometry. More than 500 proteins were identified from each preparation. Bioinformatic methods were used to characterize proteins with regard to membrane association, cellular function, and conservation across species. Numerous proteins not previously known to be spore associated, 6 in B. subtilis and 68 in B. anthracis, were identified. Relative quantitation based on spectral counting indicated that the majority of spore membrane proteins decrease in abundance during the first 20 min of germination. The spore membranes contained several proteins thought to be involved in the transport of metal ions, a process that plays a major role in spore formation and germination. Analyses of mutant strains lacking these transport proteins implicated YloB in the accumulation of calcium within the developing forespore.IMPORTANCE Bacterial endospores can remain dormant and highly resistant to environmental insults for long periods but can also rapidly germinate in response to a nutrient-rich environment. The persistence and subsequent germination of spores contribute to their colonization of new environments and to the spread of certain diseases. Proteins of Bacillus subtilis and Bacillus anthracis were identified that are associated with the spore membrane, a position that can allow them to contribute to germination. A set of identified proteins that are predicted to carry out ion transport were examined for their contributions to spore formation, stability, and germination. Greater knowledge of spore formation and germination can contribute to the development of better decontamination strategies.
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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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Liang X, Zhu J, Zhao Z, Zheng F, Zhang E, Wei J, Ji Y, Ji Y. A Single Nucleotide Polymorphism Is Involved in Regulation of Growth and Spore Formation of Bacillus anthracis Pasteur II Strain. Front Cell Infect Microbiol 2017; 7:270. [PMID: 28702375 PMCID: PMC5487402 DOI: 10.3389/fcimb.2017.00270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 06/06/2017] [Indexed: 01/03/2023] Open
Abstract
Anthrax toxins and capsules, which are encoded by genes located on pXO1 and pXO2, respectively, are major virulence factors of Bacillus anthracis. Our previous studies demonstrated that exposure to high-temperatures is unable to abolish the pXO1 plasmid of the Pasteur II strain, but the growth of the strain was obviously slower than that of the Sterne strain and wild-type virulent strain. To elucidate a potential regulatory mechanism of slowing growth, we employed comparative genome and bioinformatic analysis and revealed a unique SNP (G to T) at the 143135 bp position in pXO1 that is possibly involved in the mediation of growth of Pasteur II. However, the T to G mutation in groR did not result in any change of the amino acid sequence. A predominant nucleotide G existed at the 143135 bp in pXO1 of 100 wild-type B. anthracis isolates and 9 isolates documented in GenBank, whereas T replaced G in pXO1 of the Pasteur II strain. Further analysis indicate that the SNP is located in a gene between 143042 and 143173 bp, and that it encodes a small protein of 43 amino acids and is termed as a growth regulator (GroR). Site-directed mutagenesis and gene deletion demonstrates that groR regulates the growth and spore formation of B. anthracis. Our results indicate that the pXO1 plasmid is involved in the regulation of growth and spore formation in B. anthracis.
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Affiliation(s)
- Xudong Liang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China
| | - Jin Zhu
- Huadong Medical Institute of BiotechniquesNanjing, China
| | - Zhongzhi Zhao
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China
| | - Feng Zheng
- Huadong Medical Institute of BiotechniquesNanjing, China
| | - Enmin Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China
| | - Jianchun Wei
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China
| | - Yon Ji
- State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, National Institute for Communicable Disease Control and PreventionBeijing, China
| | - Yinduo Ji
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. PaulMN, United States
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Dik DA, Marous DR, Fisher JF, Mobashery S. Lytic transglycosylases: concinnity in concision of the bacterial cell wall. Crit Rev Biochem Mol Biol 2017. [PMID: 28644060 DOI: 10.1080/10409238.2017.1337705] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The lytic transglycosylases (LTs) are bacterial enzymes that catalyze the non-hydrolytic cleavage of the peptidoglycan structures of the bacterial cell wall. They are not catalysts of glycan synthesis as might be surmised from their name. Notwithstanding the seemingly mundane reaction catalyzed by the LTs, their lytic reactions serve bacteria for a series of astonishingly diverse purposes. These purposes include cell-wall synthesis, remodeling, and degradation; for the detection of cell-wall-acting antibiotics; for the expression of the mechanism of cell-wall-acting antibiotics; for the insertion of secretion systems and flagellar assemblies into the cell wall; as a virulence mechanism during infection by certain Gram-negative bacteria; and in the sporulation and germination of Gram-positive spores. Significant advances in the mechanistic understanding of each of these processes have coincided with the successive discovery of new LTs structures. In this review, we provide a systematic perspective on what is known on the structure-function correlations for the LTs, while simultaneously identifying numerous opportunities for the future study of these enigmatic enzymes.
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Affiliation(s)
- David A Dik
- a Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN , USA
| | - Daniel R Marous
- a Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN , USA
| | - Jed F Fisher
- a Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN , USA
| | - Shahriar Mobashery
- a Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , IN , USA
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14
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‘Omics’ for microbial food stability: Proteomics for the development of predictive models for bacterial spore stress survival and outgrowth. Int J Food Microbiol 2017; 240:11-18. [DOI: 10.1016/j.ijfoodmicro.2016.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/03/2016] [Accepted: 05/06/2016] [Indexed: 12/25/2022]
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15
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Zheng L, Abhyankar W, Ouwerling N, Dekker HL, van Veen H, van der Wel NN, Roseboom W, de Koning LJ, Brul S, de Koster CG. Bacillus subtilis Spore Inner Membrane Proteome. J Proteome Res 2016; 15:585-94. [PMID: 26731423 DOI: 10.1021/acs.jproteome.5b00976] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The endospore is the dormant form of Bacillus subtilis and many other Firmicutes. By sporulation, these spore formers can survive very harsh physical and chemical conditions. Yet, they need to go through germination to return to their growing form. The spore inner membrane (IM) has been shown to play an essential role in triggering the initiation of germination. In this study, we isolated the IM of bacterial spores, in parallel with the isolation of the membrane of vegetative cells. With the use of GeLC-MS/MS, over 900 proteins were identified from the B. subtilis spore IM preparations. By bioinformatics-based membrane protein predictions, ca. one-third could be predicted to be membrane-localized. A large number of unique proteins as well as proteins common to the two membrane proteomes were identified. In addition to previously known IM proteins, a number of IM proteins were newly identified, at least some of which are likely to provide new insights into IM physiology, unveiling proteins putatively involved in spore germination machinery and hence putative germination inhibition targets.
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Affiliation(s)
| | | | | | | | - Henk van Veen
- Electron Microscopy Centre Amsterdam, Department of Cell Biology and Histology, Academic Medical Center , 1105 AZ Amsterdam, The Netherlands
| | - Nicole N van der Wel
- Electron Microscopy Centre Amsterdam, Department of Cell Biology and Histology, Academic Medical Center , 1105 AZ Amsterdam, The Netherlands
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16
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Improvements to a Markerless Allelic Exchange System for Bacillus anthracis. PLoS One 2015; 10:e0142758. [PMID: 26624016 PMCID: PMC4666636 DOI: 10.1371/journal.pone.0142758] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/20/2015] [Indexed: 11/25/2022] Open
Abstract
A system was previously developed for conducting I-SceI-mediated allelic exchange in Bacillus anthracis. In this system, recombinational loss of a chromosomally-integrated allelic exchange vector is stimulated by creation of a double-stranded break within the vector by the homing endonuclease I-SceI. Although this system is reasonably efficient and represents an improvement in the tools available for allelic exchange in B. anthracis, researchers are nonetheless required to “pick and patch” colonies in order to identify candidate "exchangeants." In the present study, a number of improvements have been made to this system: 1) an improved I-SceI-producing plasmid includes oriT so that both plasmids can now be introduced by conjugation, thus avoiding the need for preparing electro-competent cells of each integration intermediate; 2) antibiotic markers have been changed to allow the use of the system in select agent strains; and 3) both plasmids have been marked with fluorescent proteins, allowing the visualization of plasmid segregation on a plate and obviating the need for “picking and patching.” These modifications have made the process easier, faster, and more efficient, allowing for parallel construction of larger numbers of mutant strains. Using this improved system, the genes encoding the tripartite anthrax toxin were deleted singly and in combination from plasmid pXO1 of Sterne strain 34F2. In the course of this study, we determined that DNA transfer to B. anthracis could be accomplished by conjugation directly from a methylation-competent E. coli strain.
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17
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Üstok FI, Chirgadze DY, Christie G. Crystal structure of the PepSY-containing domain of the YpeB protein involved in germination of bacillus
spores. Proteins 2015. [DOI: 10.1002/prot.24868] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fatma Işık Üstok
- Department of Chemical Engineering and Biotechnology; Institute of Biotechnology, 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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