1
|
Khan F, Jeong GJ, Tabassum N, Mishra A, Kim YM. Filamentous morphology of bacterial pathogens: regulatory factors and control strategies. Appl Microbiol Biotechnol 2022; 106:5835-5862. [PMID: 35989330 DOI: 10.1007/s00253-022-12128-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/03/2022] [Accepted: 08/06/2022] [Indexed: 11/24/2022]
Abstract
Several studies have demonstrated that when exposed to physical, chemical, and biological stresses in the environment, many bacteria (Gram-positive and Gram-negative) change their morphology from a normal cell to a filamentous shape. The formation of filamentous morphology is one of the survival strategies against environmental stress and protection against phagocytosis or protist predators. Numerous pathogenic bacteria have shown filamentous morphologies when examined in vivo or in vitro. During infection, certain pathogenic bacteria adopt a filamentous shape inside the cell to avoid phagocytosis by immune cells. Filamentous morphology has also been seen in biofilms formed on biotic or abiotic surfaces by certain bacteria. As a result, in addition to protecting against phagocytosis by immune cells or predators, the filamentous shape aids in biofilm adhesion or colonization to biotic or abiotic surfaces. Furthermore, these filamentous morphologies of bacterial pathogens lead to antimicrobial drug resistance. Clinically, filamentous morphology has become one of the most serious challenges in treating bacterial infection. The current review went into great detail about the various factors involved in the change of filamentous morphology and the underlying mechanisms. In addition, the review discussed a control strategy for suppressing filamentous morphology in order to combat bacterial infections. Understanding the mechanism underlying the filamentous morphology induced by various environmental conditions will aid in drug development and lessen the virulence of bacterial pathogens. KEY POINTS: • The bacterial filamentation morphology is one of the survival mechanisms against several environmental stress conditions and protection from phagocytosis by host cells and protist predators. • The filamentous morphologies in bacterial pathogens contribute to enhanced biofilm formation, which develops resistance properties against antimicrobial drugs. • Filamentous morphology has become one of the major hurdles in treating bacterial infection, hence controlling strategies employed for inhibiting the filamentation morphology from combating bacterial infections.
Collapse
Affiliation(s)
- Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea. .,Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
| | - Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Nazia Tabassum
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Akanksha Mishra
- Department of Biotechnology, Division of Research and Development, Lovely Professional University, Phagwara, Punjab, 144001, India
| | - Young-Mog Kim
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea. .,Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea. .,Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea.
| |
Collapse
|
2
|
Dawson CC, Cummings JE, Starkey JM, Slayden RA. Discovery of a novel type IIb RelBE toxin-antitoxin system in Mycobacterium tuberculosis defined by co-regulation with an antisense RNA. Mol Microbiol 2022; 117:1419-1433. [PMID: 35526138 PMCID: PMC9325379 DOI: 10.1111/mmi.14917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 04/30/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022]
Abstract
Toxin‐antitoxin loci regulate adaptive responses to stresses associated with the host environment and drug exposure. Phylogenomic studies have shown that Mycobacterium tuberculosis encodes a naturally expanded type II toxin‐antitoxin system, including ParDE/RelBE superfamily members. Type II toxins are presumably regulated exclusively through protein–protein interactions with type II antitoxins. However, experimental observations in M. tuberculosis indicated that additional control mechanisms regulate RelBE2 type II loci under host‐associated stress conditions. Herein, we describe for the first time a novel antisense RNA, termed asRelE2, that co‐regulates RelE2 production via targeted processing by the Mtb RNase III, Rnc. We find that convergent expression of this coding‐antisense hybrid TA locus, relBE2‐asrelE2, is controlled in a cAMP‐dependent manner by the essential cAMP receptor protein transcription factor, Crp, in response to the host‐associated stresses of low pH and nutrient limitation. Ex vivo survival studies with relE2 and asrelE2 knockout strains showed that RelE2 contributes to Mtb survival in activated macrophages and low pH to nutrient limitation. To our knowledge, this is the first report of a novel tripartite type IIb TA loci and antisense post‐transcriptional regulation of a type II TA loci.
Collapse
Affiliation(s)
- Clinton C Dawson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins.,Endolytix Technology, Inc. Beverly, 01915
| | - Jason E Cummings
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins
| | - Julie M Starkey
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins
| | - Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins
| |
Collapse
|
3
|
Chattopadhyay G, Bhasin M, Ahmed S, Gosain TP, Ganesan S, Das S, Thakur C, Chandra N, Singh R, Varadarajan R. Functional and Biochemical Characterization of the MazEF6 Toxin-Antitoxin System of Mycobacterium tuberculosis. J Bacteriol 2022; 204:e0005822. [PMID: 35357163 PMCID: PMC9053165 DOI: 10.1128/jb.00058-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/07/2022] [Indexed: 12/15/2022] Open
Abstract
The Mycobacterium tuberculosis genome harbors nine toxin-antitoxin (TA) systems that are members of the mazEF family, unlike other prokaryotes, which have only one or two. Although the overall tertiary folds of MazF toxins are predicted to be similar, it is unclear how they recognize structurally different RNAs and antitoxins with divergent sequence specificity. Here, we have expressed and purified the individual components and complex of the MazEF6 TA system from M. tuberculosis. Size exclusion chromatography-multiangle light scattering (SEC-MALS) was performed to determine the oligomerization status of the toxin, antitoxin, and the complex in different stoichiometric ratios. The relative stabilities of the proteins were determined by nano-differential scanning fluorimetry (nano-DSF). Microscale thermophoresis (MST) and yeast surface display (YSD) were performed to measure the relative affinities between the cognate toxin-antitoxin partners. The interaction between MazEF6 complexes and cognate promoter DNA was also studied using MST. Analysis of paired-end RNA sequencing data revealed that the overexpression of MazF6 resulted in differential expression of 323 transcripts in M. tuberculosis. Network analysis was performed to identify the nodes from the top-response network. The analysis of mRNA protection ratios resulted in identification of putative MazF6 cleavage site in its native host, M. tuberculosis. IMPORTANCE M. tuberculosis harbors a large number of type II toxin-antitoxin (TA) systems, the exact roles for most of which are unclear. Prior studies have reported that overexpression of several of these type II toxins inhibits bacterial growth and contributes to the formation of drug-tolerant populations in vitro. To obtain insights into M. tuberculosis MazEF6 type II TA system function, we determined stability, oligomeric states, and binding affinities of cognate partners with each other and with their promoter operator DNA. Using RNA-seq data obtained from M. tuberculosis overexpression strains, we have identified putative MazF6 cleavage sites and targets in its native, cellular context.
Collapse
Affiliation(s)
| | - Munmun Bhasin
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Shahbaz Ahmed
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Tannu Priya Gosain
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Srivarshini Ganesan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
| | - Sayan Das
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Chandrani Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Nagasuma Chandra
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Ramandeep Singh
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Raghavan Varadarajan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| |
Collapse
|
4
|
DivIVA Regulates Its Expression and the Orientation of New Septum Growth in Deinococcus radiodurans. J Bacteriol 2021; 203:e0016321. [PMID: 34031039 DOI: 10.1128/jb.00163-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In rod-shaped Gram-negative bacteria, FtsZ localization at midcell position is regulated by the gradient of MinCDE complex across the poles. In round-shaped bacteria, which lack predefined poles, the next plane of cell division is perpendicular to the previous plane, and determination of the FtsZ assembly site is still intriguing. Deinococcus radiodurans, a coccus bacterium, is characterized by its extraordinary resistance to DNA damage. DivIVA, a putative component of the Min system in this bacterium, interacts with cognate cell division and genome segregation proteins. Here, we report that deletion of a chromosomal copy of DivIVA was possible only when the wild-type copy of DivIVA was expressed in trans on a plasmid. However, deletion of the C-terminal domain (CTD) of DivIVA (CTD mutant) was possible but produced distinguishable phenotypes, like smaller cells, slower growth, and tilted septum orientation, in D. radiodurans. In trans expression of DivIVA in the CTD mutant could restore these features of the wild type. Interestingly, the overexpression of DivIVA led to delayed separation of tetrads from an octet state in both trans-complemented divIVA-mutant and wild-type cells. The CTD mutant showed upregulation of the yggS-divIVAN operon. Both the wild type and CTD mutant formed FtsZ foci; however, unlike wild type, the position of foci in the mutant cells was found to be away from conjectural midcell position in cocci. Notably, DivIVA-red fluorescent protein (DivIVA-RFP) localizes to the septum during cell division at the new division site. These results suggested that DivIVA is an essential protein in D. radiodurans, and its C-terminal domain plays an important role in the regulation of its expression and orientation of new septal growth in this bacterium. IMPORTANCE In rod-shaped Gram-negative bacteria, the midcell position for binary fission is relatively easy to model. In cocci that do not have predefined poles, the plane of next cell division is shown to be perpendicular to the previous plane. However, the molecular basis of perpendicularity is not known in cocci. The DivIVA protein of Deinococcus radiodurans, a coccus bacterium, physically interacts with the septum and establishes macromolecular interactions with genome segregation proteins through its N-terminal domain and with MinC through the C-terminal domain. Here, we have brought forth some evidence to suggest that DivIVA is essential for growth and plays an important role in cell polarity determination, and its C-terminal domain plays a crucial role in the growth of new septa in the correct orientation as well as in the regulation of DivIVA expression.
Collapse
|
5
|
Wu G, Zhang Y, Wang B, Li K, Lou Y, Zhao Y, Liu F. Proteomic and Transcriptomic Analyses Provide Novel Insights into the Crucial Roles of Host-Induced Carbohydrate Metabolism Enzymes in Xanthomonas oryzae pv. oryzae Virulence and Rice-Xoo Interaction. RICE (NEW YORK, N.Y.) 2021; 14:57. [PMID: 34176023 PMCID: PMC8236019 DOI: 10.1186/s12284-021-00503-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/11/2021] [Indexed: 05/19/2023]
Abstract
BACKGROUND Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight, a devastating rice disease. The Xoo-rice interaction, wherein wide ranging host- and pathogen-derived proteins and genes wage molecular arms race, is a research hotspot. Hence, the identification of novel rice-induced Xoo virulence factors and characterization of their roles affecting rice global gene expression profiles will provide an integrated and better understanding of Xoo-rice interactions from the molecular perspective. RESULTS Using comparative proteomics and an in vitro interaction system, we revealed that 5 protein spots from Xoo exhibited significantly different expression patterns (|fold change| > 1.5) at 3, 6, 12 h after susceptible rice leaf extract (RLX) treatment. MALDI-TOF MS analysis and pathogenicity tests showed that 4 host-induced proteins, including phosphohexose mutase, inositol monophosphatase, arginase and septum site-determining protein, affected Xoo virulence. Among them, mutants of two host-induced carbohydrate metabolism enzyme-encoding genes, ΔxanA and Δimp, elicited enhanced defense responses and nearly abolished Xoo virulence in rice. To decipher rice differentially expressed genes (DEGs) associated with xanA and imp, transcriptomic responses of ΔxanA-treated and Δimp-treated susceptible rice were compared to those in rice treated with PXO99A at 1 and 3 dpi. A total of 1521 and 227 DEGs were identified for PXO99A vs Δimp at 1 and 3 dpi, while for PXO99A vs ΔxanA, there were 131 and 106 DEGs, respectively. GO, KEGG and MapMan analyses revealed that the DEGs for PXO99A vs Δimp were mainly involved in photosynthesis, signal transduction, transcription, oxidation-reduction, hydrogen peroxide catabolism, ion transport, phenylpropanoid biosynthesis and metabolism of carbohydrates, lipids, amino acids, secondary metabolites, hormones, and nucleotides, while the DEGs from PXO99A vs ΔxanA were predominantly associated with photosynthesis, signal transduction, oxidation-reduction, phenylpropanoid biosynthesis, cytochrome P450 and metabolism of carbohydrates, lipids, amino acids, secondary metabolites and hormones. Although most pathways were associated with both the Δimp and ΔxanA treatments, the underlying genes were not the same. CONCLUSION Our study identified two novel host-induced virulence factors XanA and Imp in Xoo, and revealed their roles in global gene expression in susceptible rice. These results provide valuable insights into the molecular mechanisms of pathogen infection strategies and plant immunity.
Collapse
Affiliation(s)
- Guichun Wu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, No. 50 Zhongling Street, Nanjing, Jiangsu, 210014, P. R. China
| | - Yuqiang Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, 266237, P. R. China
| | - Bo Wang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, No. 50 Zhongling Street, Nanjing, Jiangsu, 210014, P. R. China
| | - Kaihuai Li
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Yuanlai Lou
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, No. 50 Zhongling Street, Nanjing, Jiangsu, 210014, P. R. China
| | - Yancun Zhao
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, No. 50 Zhongling Street, Nanjing, Jiangsu, 210014, P. R. China.
| | - Fengquan Liu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, No. 50 Zhongling Street, Nanjing, Jiangsu, 210014, P. R. China.
| |
Collapse
|
6
|
Wu Z, Wei W, Zhou Y, Guo H, Zhao J, Liao Q, Chen L, Zhang X, Zhou L. Integrated Quantitative Proteomics and Metabolome Profiling Reveal MSMEG_6171 Overexpression Perturbing Lipid Metabolism of Mycobacterium smegmatis Leading to Increased Vancomycin Resistance. Front Microbiol 2020; 11:1572. [PMID: 32793136 PMCID: PMC7393984 DOI: 10.3389/fmicb.2020.01572] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 06/17/2020] [Indexed: 01/29/2023] Open
Abstract
In recent years, the treatment of tuberculosis is once again facing a severe situation because the existing antituberculosis drugs have become weaker and weaker with the emergence of drug-resistant Mycobacterium tuberculosis (Mtb). The studies of cell division and cell cycle-related factors in Mtb are particularly important for the development of new drugs with broad-spectrum effects. Mycobacterium smegmatis (Msm) has been used as a model organism to study the molecular, physiological, and drug-resistant mechanisms of Mtb. Bioinformatics analysis has predicted that MSMEG_6171 is a MinD-like protein of the septum site-determining protein family associated with cell division in Mycobacterium smegmatis. In our study, we use ultrastructural analysis, proteomics, metabolomics, and molecular biology techniques to comprehensively investigate the function of MSMEG_6171. Overexpression of MSMEG_6171 in Msm resulted in elongated cells, suggesting an important role of MSMEG_6171 in regulating cell wall morphology. The MSMEG_6171 overexpression could enhance the bacterial resistance to vancomycin, ethionamide, meropenem, and cefamandole. The MSMEG_6171 overexpression could alter the lipid metabolism of Msm to cause the changes on cellular biofilm property and function, which enhances bacterial resistance to antibiotics targeting cell wall synthesis. MSMEG_6171 could also induce the glyceride and phospholipid alteration in vivo to exhibit the pleiotropic phenotypes and various cellular responses. The results showed that amino acid R249 in MSMEG_6171 was a key site that can affect the level of bacterial drug resistance, suggesting that ATPase activity is required for function.
Collapse
Affiliation(s)
- Zhuhua Wu
- Key Laboratory of Translational Medicine of Guangdong, Center for Tuberculosis Control of Guangdong Province, Guangzhou, China
| | - Wenjing Wei
- Key Laboratory of Translational Medicine of Guangdong, Center for Tuberculosis Control of Guangdong Province, Guangzhou, China
| | - Ying Zhou
- School of Stomatology and Medicine, Foshan University, Foshan, China
| | - Huixin Guo
- Key Laboratory of Translational Medicine of Guangdong, Center for Tuberculosis Control of Guangdong Province, Guangzhou, China
| | - Jiao Zhao
- School of Medicine, Jinan University, Guangzhou, China
| | - Qinghua Liao
- Key Laboratory of Translational Medicine of Guangdong, Center for Tuberculosis Control of Guangdong Province, Guangzhou, China
| | - Liang Chen
- Key Laboratory of Translational Medicine of Guangdong, Center for Tuberculosis Control of Guangdong Province, Guangzhou, China
| | - Xiaoli Zhang
- School of Stomatology and Medicine, Foshan University, Foshan, China
| | - Lin Zhou
- Key Laboratory of Translational Medicine of Guangdong, Center for Tuberculosis Control of Guangdong Province, Guangzhou, China
| |
Collapse
|
7
|
Rivas-Marin E, Peeters SH, Claret Fernández L, Jogler C, van Niftrik L, Wiegand S, Devos DP. Non-essentiality of canonical cell division genes in the planctomycete Planctopirus limnophila. Sci Rep 2020; 10:66. [PMID: 31919386 PMCID: PMC6952346 DOI: 10.1038/s41598-019-56978-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 12/19/2019] [Indexed: 12/13/2022] Open
Abstract
Most bacteria divide by binary fission using an FtsZ-based mechanism that relies on a multi-protein complex, the divisome. In the majority of non-spherical bacteria another multi-protein complex, the elongasome, is also required for the maintenance of cell shape. Components of these multi-protein assemblies are conserved and essential in most bacteria. Here, we provide evidence that at least three proteins of these two complexes are not essential in the FtsZ-less ovoid planctomycete bacterium Planctopirus limnophila which divides by budding. We attempted to construct P. limnophila knock-out mutants of the genes coding for the divisome proteins FtsI, FtsK, FtsW and the elongasome protein MreB. Surprisingly, ftsI, ftsW and mreB could be deleted without affecting the growth rate. On the other hand, the conserved ftsK appeared to be essential in this bacterium. In conclusion, the canonical bacterial cell division machinery is not essential in P. limnophila and this bacterium divides via budding using an unknown mechanism.
Collapse
Affiliation(s)
- Elena Rivas-Marin
- Centro Andaluz de Biología del Desarrollo (CABD)-CSIC, Pablo de Olavide University, Seville, Spain
| | - Stijn H Peeters
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, The Netherlands
| | - Laura Claret Fernández
- Centro Andaluz de Biología del Desarrollo (CABD)-CSIC, Pablo de Olavide University, Seville, Spain.,Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, The Netherlands
| | - Christian Jogler
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, The Netherlands.,Institute of Microbiology, Department of Microbial Interactions, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Laura van Niftrik
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, The Netherlands
| | - Sandra Wiegand
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, The Netherlands
| | - Damien P Devos
- Centro Andaluz de Biología del Desarrollo (CABD)-CSIC, Pablo de Olavide University, Seville, Spain.
| |
Collapse
|
8
|
Abstract
How do mycobacteria divide? Cell division has been studied extensively in the model rod-shaped bacteria Escherichia coli and Bacillus subtilis, but much less is understood about cell division in mycobacteria, a genus that includes the major human pathogens M. tuberculosis and M. leprae. In general, bacterial cell division requires the concerted effort of many proteins in both space and time to elongate the cell, replicate and segregate the chromosome, and construct and destruct the septum - processes which result in the creation of two new daughter cells. Here, we describe these distinct stages of cell division in B. subtilis and follow with the current knowledge in mycobacteria. As will become apparent, there are many differences between mycobacteria and B. subtilis in terms of both the broad outline of cell division and the molecular details. So, while the fundamental challenge of spatially and temporally organizing cell division is shared between these rod-shaped bacteria, they have solved these challenges in often vastly different ways.
Collapse
|
9
|
Slayden RA, Dawson CC, Cummings JE. Toxin-antitoxin systems and regulatory mechanisms in Mycobacterium tuberculosis. Pathog Dis 2018; 76:4969681. [PMID: 29788125 DOI: 10.1093/femspd/fty039] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/01/2018] [Indexed: 11/14/2022] Open
Abstract
There has been a significant reduction in annual tuberculosis incidence since the World Health Organization declared tuberculosis a global health threat. However, treatment of M. tuberculosis infections requires lengthy multidrug therapeutic regimens to achieve a durable cure. The development of new drugs that are active against resistant strains and phenotypically diverse organisms continues to present the greatest challenge in the future. Numerous phylogenomic analyses have revealed that the Mtb genome encodes a significantly expanded repertoire of toxin-antitoxin (TA) loci that makes up the Mtb TA system. A TA loci is a two-gene operon encoding a 'toxin' protein that inhibits bacterial growth and an interacting 'antitoxin' partner that neutralizes the inhibitory activity of the toxin. The presence of multiple chromosomally encoded TA loci in Mtb raises important questions in regard to expansion, regulation and function. Thus, the functional roles of TA loci in Mtb pathogenesis have received considerable attention over the last decade. The cumulative results indicate that they are involved in regulating adaptive responses to stresses associated with the host environment and drug treatment. Here we review the TA families encoded in Mtb, discuss the duplication of TA loci in Mtb, regulatory mechanism of TA loci, and phenotypic heterogeneity and pathogenesis.
Collapse
Affiliation(s)
- Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| | - Clinton C Dawson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| | - Jason E Cummings
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| |
Collapse
|
10
|
Jain P, Malakar B, Khan MZ, Lochab S, Singh A, Nandicoori VK. Delineating FtsQ-mediated regulation of cell division in Mycobacterium tuberculosis. J Biol Chem 2018; 293:12331-12349. [PMID: 29903917 DOI: 10.1074/jbc.ra118.003628] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/31/2018] [Indexed: 11/06/2022] Open
Abstract
Identifying and characterizing the individual contributors to bacterial cellular elongation and division will improve our understanding of their impact on cell growth and division. Here, we delineated the role of ftsQ, a terminal gene of the highly conserved division cell wall (dcw) operon, in growth, survival, and cell length maintenance in the human pathogen Mycobacterium tuberculosis (Mtb). We found that FtsQ overexpression significantly increases the cell length and number of multiseptate cells. FtsQ depletion in Mtb resulted in cells that were shorter than WT cells during the initial growth stages (4 days after FtsQ depletion) but were longer than WT cells at later stages (10 days after FtsQ depletion) and compromised the survival in vitro and in differentiated THP1 macrophages. Overexpression of N- and C-terminal FtsQ regions altered the cell length, and the C-terminal domain alone complemented the FtsQ depletion phenotype. MS analyses suggested robust FtsQ phosphorylation on Thr-24, and although phosphoablative and -mimetic mutants rescued the FtsQ depletion-associated cell viability defects, they failed to complement the cell length defects. MS and coimmunoprecipitation experiments identified 63 FtsQ-interacting partners, and we show that the interaction of FtsQ with the recently identified cell division protein SepIVA is independent of FtsQ phosphorylation and suggests a role of FtsQ in modulating cell division. FtsQ exhibited predominantly septal localization in both the presence and absence of SepIVA. Our results suggest a role for FtsQ in modulating the length, division, and survival of Mtb cells both in vitro and in the host.
Collapse
Affiliation(s)
- Preeti Jain
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067 and
| | - Basanti Malakar
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067 and
| | - Mehak Zahoor Khan
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067 and
| | - Savita Lochab
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067 and
| | - Archana Singh
- Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, New Delhi 110025, India
| | | |
Collapse
|
11
|
Puffal J, García-Heredia A, Rahlwes KC, Siegrist MS, Morita YS. Spatial control of cell envelope biosynthesis in mycobacteria. Pathog Dis 2018; 76:4953754. [DOI: 10.1093/femspd/fty027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/25/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Julia Puffal
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Alam García-Heredia
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| |
Collapse
|
12
|
Abstract
The last three decades have witnessed an explosion of discoveries about the mechanistic details of binary fission in model bacteria such as Escherichia coli, Bacillus subtilis, and Caulobacter crescentus. This was made possible not only by advances in microscopy that helped answer questions about cell biology but also by clever genetic manipulations that directly and easily tested specific hypotheses. More recently, research using understudied organisms, or nonmodel systems, has revealed several alternate mechanistic strategies that bacteria use to divide and propagate. In this review, we highlight new findings and compare these strategies to cell division mechanisms elucidated in model organisms.
Collapse
Affiliation(s)
- Prahathees J Eswara
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, Florida 33620;
| | - Kumaran S Ramamurthi
- Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-5132;
| |
Collapse
|
13
|
Tong J, Meng L, Wang X, Liu L, Lyu L, Wang C, Li Y, Gao Q, Yang C, Niu C. The FBPase Encoding Gene glpX Is Required for Gluconeogenesis, Bacterial Proliferation and Division In Vivo of Mycobacterium marinum. PLoS One 2016; 11:e0156663. [PMID: 27233038 PMCID: PMC4883791 DOI: 10.1371/journal.pone.0156663] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/17/2016] [Indexed: 01/12/2023] Open
Abstract
Lipids have been identified as important carbon sources for Mycobacterium tuberculosis (Mtb) to utilize in vivo. Thus gluconeogenesis bears a key role for Mtb to survive and replicate in host. A rate-limiting enzyme of gluconeogenesis, fructose 1, 6-bisphosphatase (FBPase) is encoded by the gene glpX. The functions of glpX were studied in M. marinum, a closely related species to Mtb. The glpX deletion strain (ΔglpX) displayed altered gluconeogenesis, attenuated virulence, and altered bacterial proliferation. Metabolic profiles indicate an accumulation of the FBPase substrate, fructose 1, 6-bisphosphate (FBP) and altered gluconeogenic flux when ΔglpX is cultivated in a gluconeogenic carbon substrate, acetate. In both macrophages and zebrafish, the proliferation of ΔglpX was halted, resulting in dramatically attenuated virulence. Intracellular ΔglpX exhibited an elongated morphology, which was also observed when ΔglpX was grown in a gluconeogenic carbon source. This elongated morphology is also supported by the observation of unseparated multi-nucleoid cell, indicating that a complete mycobacterial division in vivo is correlated with intact gluconeogenesis. Together, our results indicate that glpX has essential functions in gluconeogenesis, and plays an indispensable role in bacterial proliferation in vivo and virulence of M. marinum.
Collapse
Affiliation(s)
- Jingfeng Tong
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Lu Meng
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Institutes of Biomedical Sciences and Institute of Medical Microbiology, Fudan University, Shanghai, China
| | - Xinwei Wang
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Lixia Liu
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Liangdong Lyu
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Chuan Wang
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yang Li
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Qian Gao
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Institutes of Biomedical Sciences and Institute of Medical Microbiology, Fudan University, Shanghai, China
| | - Chen Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (CY); (CN)
| | - Chen Niu
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
- * E-mail: (CY); (CN)
| |
Collapse
|
14
|
Kirsebom LA, Dasgupta S, Fredrik Pettersson BM. Pleiomorphism in Mycobacterium. ADVANCES IN APPLIED MICROBIOLOGY 2016; 80:81-112. [PMID: 22794145 DOI: 10.1016/b978-0-12-394381-1.00004-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Morphological variants in mycobacterial cultures under different growth conditions, including aging of the culture, have been shown to include fibrous aggregates, biofilms, coccoids, and spores. Here we discuss the diversity in shape and size changes demonstrated by bacterial cells with special reference to pleiomorphism observed in Mycobacterium spp. in response to nutritional and other environmental stresses. Inherent asymmetry in cell division and compartmentalization of cell interior under different growth conditions might contribute toward the observed pleiomorphism in mycobacteria. The regulatory genes comprising the bacterial signaling pathway responsible for initiating morphogenesis are speculated upon from bioinformatic identifications of genes for known sensors, kinases, and phosphatases existing in mycobacterial genomes as well as on the basis of what is known in other bacteria.
Collapse
|
15
|
Abstract
The complex cell envelope is a hallmark of mycobacteria and is anchored by the peptidoglycan layer, which is similar to that of Escherichia coli and a number of other bacteria but with modifications to the monomeric units and other structural complexities that are likely related to a role for the peptidoglycan in stabilizing the mycolyl-arabinogalactan-peptidoglycan complex (MAPc). In this article, we will review the genetics of several aspects of peptidoglycan biosynthesis in mycobacteria, including the production of monomeric precursors in the cytoplasm, assembly of the monomers into the mature wall, cell wall turnover, and cell division. Finally, we will touch upon the resistance of mycobacteria to β-lactam antibiotics, an important class of drugs that, until recently, have not been extensively exploited as potential antimycobacterial agents. We will also note areas of research where there are still unanswered questions.
Collapse
|
16
|
Ramsugit S, Pillay M. Pili of Mycobacterium tuberculosis: current knowledge and future prospects. Arch Microbiol 2015; 197:737-44. [PMID: 25975850 DOI: 10.1007/s00203-015-1117-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/02/2015] [Accepted: 05/05/2015] [Indexed: 11/29/2022]
Abstract
Many pathogenic bacteria express filamentous appendages, termed pili, on their surface. These organelles function in several important bacterial processes, including mediating bacterial interaction with, and colonization of the host, signalling events, locomotion, DNA uptake, electric conductance, and biofilm formation. In the last decade, it has been established that the tuberculosis-causing bacterium, Mycobacterium tuberculosis, produces two pili types: curli and type IV pili. In this paper, we review studies on M. tuberculosis pili, highlighting their structure and biological significance to M. tuberculosis pathogenesis, and discuss their potential as targets for therapeutic intervention and diagnostic test development.
Collapse
Affiliation(s)
- Saiyur Ramsugit
- Medical Microbiology and Infection Control, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, 1st Floor Doris Duke Medical Research Institute, Private Bag 7, Congella, Durban, 4013, South Africa
| | | |
Collapse
|
17
|
MadR1, a Mycobacterium tuberculosis cell cycle stress response protein that is a member of a widely conserved protein class of prokaryotic, eukaryotic and archeal origin. Tuberculosis (Edinb) 2015; 95:251-8. [PMID: 25829286 DOI: 10.1016/j.tube.2015.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 03/08/2015] [Indexed: 11/21/2022]
Abstract
Stress-induced molecular programs designed to stall division progression are nearly ubiquitous in bacteria, with one well-known example being the participation of the SulA septum inhibiting protein in the SOS DNA damage repair response. Mycobacteria similarly demonstrate stress-altered growth kinetics, however no such regulators have been found in these organisms. We therefore set out to identify SulA-like regulatory proteins in Mycobacterium tuberculosis. A bioinformatics modeling-based approach led to the identification of rv2216 as encoding for a protein with weak similarity to SulA, further analysis distinguished this protein as belonging to a group of uncharacterized growth promoting proteins. We have named the mycobacterial protein encoded by rv2216 morphology altering division regulator protein 1, MadR1. Overexpression of madR1 modulated cell length while maintaining growth kinetics similar to wild-type, and increased the proportion of bent or V-form cells in the population. The presence of MadR1-GFP at regions of cellular elongation (poles) and morphological differentiation (V-form) suggests MadR1 involvement in phenotypic heterogeneity and longitudinal cellular growth. Global transcriptional analysis indicated that MadR1 functionality is linked to lipid editing programs required for growth and persistence. This is the first report to differentiate the larger class of these conserved proteins from SulA proteins and characterizes MadR1 effects on the mycobacterial cell.
Collapse
|
18
|
Mycobacterium tuberculosis dormancy-associated antigen of Rv2660c induces stronger immune response in latent Mycobacterium tuberculosis infection than that in active tuberculosis in a Chinese population. Eur J Clin Microbiol Infect Dis 2015; 34:1103-9. [DOI: 10.1007/s10096-015-2335-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/21/2015] [Indexed: 11/27/2022]
|
19
|
Abstract
Mycobacterium tuberculosis, which is the aetiological agent of tuberculosis, owes much of its success as a pathogen to its unique cell wall and unusual mechanism of growth, which facilitate its adaptation to the human host and could have a role in clinical latency. Asymmetric growth and division increase population heterogeneity, which may promote antibiotic tolerance and the fitness of single cells. In this Review, we describe the unusual mechanisms of mycobacterial growth, cell wall biogenesis and division, and discuss how these processes might affect the survival of M. tuberculosis in vivo and contribute to the persistence of infection.
Collapse
|
20
|
Abstract
Efforts to understand the molecular basis of mycobacterial gene regulation are dominated by a protein-centric view. However, there is a growing appreciation that noncoding RNA, i.e., RNA that is not translated, plays a role in a wide variety of molecular mechanisms. Noncoding RNA comprises rRNA, tRNA, 4.5S RNA, RnpB, and transfer-messenger RNA, as well as a vast population of regulatory RNA, often dubbed "the dark matter of gene regulation." The regulatory RNA species comprise 5' and 3' untranslated regions and a rapidly expanding category of transcripts with the ability to base-pair with mRNAs or to interact with proteins. Regulatory RNA plays a central role in the bacterium's response to changes in the environment, and in this article we review emerging information on the presence and abundance of different types of noncoding RNA in mycobacteria.
Collapse
|
21
|
Ramirez MV, Dawson CC, Crew R, England K, Slayden RA. MazF6 toxin of Mycobacterium tuberculosis demonstrates antitoxin specificity and is coupled to regulation of cell growth by a Soj-like protein. BMC Microbiol 2013; 13:240. [PMID: 24172039 PMCID: PMC3834876 DOI: 10.1186/1471-2180-13-240] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/24/2013] [Indexed: 09/03/2023] Open
Abstract
Background Molecular programs employed by Mycobacterium tuberculosis (Mtb) for the establishment of non-replicating persistence (NRP) are poorly understood. In order to investigate mechanisms regulating entry into NRP, we asked how cell cycle regulation is linked to downstream adaptations that ultimately result in NRP. Based on previous reports and our recent studies, we reason that, in order to establish NRP, cells are halted in the cell cycle at the point of septum formation by coupled regulatory mechanisms. Results Using bioinformatic consensus modeling, we identified an alternative cell cycle regulatory element, SojMtb encoded by rv1708. SojMtb coordinates a regulatory mechanism involving cell cycle control at the point of septum formation and elicits the induction of the MazF6 toxin. MazF6 functions as an mRNA interferase leading to bacteriostasis that can be prevented by interaction with its cognate antitoxin, MazE6. Further, MazEF6 acts independently of other Maz family toxin:antitoxin pairs. Notably, sojMtb and mazEF6 transcripts where identified at 20, 40 and 100 days post-infection in increasing abundance indicating a role in adaption during chronic infection. Conclusions Here we present the first evidence of a coupled regulatory system in which cell cycle regulation via SojMtb is linked to downstream adaptations that are facilitated through the activity of the MazEF6 TA pair.
Collapse
Affiliation(s)
| | | | | | | | - Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
| |
Collapse
|
22
|
Burke C, Liu M, Britton W, Triccas JA, Thomas T, Smith AL, Allen S, Salomon R, Harry E. Harnessing single cell sorting to identify cell division genes and regulators in bacteria. PLoS One 2013; 8:e60964. [PMID: 23565292 PMCID: PMC3614548 DOI: 10.1371/journal.pone.0060964] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/04/2013] [Indexed: 11/19/2022] Open
Abstract
Cell division is an essential cellular process that requires an array of known and unknown proteins for its spatial and temporal regulation. Here we develop a novel, high-throughput screening method for the identification of bacterial cell division genes and regulators. The method combines the over-expression of a shotgun genomic expression library to perturb the cell division process with high-throughput flow cytometry sorting to screen many thousands of clones. Using this approach, we recovered clones with a filamentous morphology for the model bacterium, Escherichia coli. Genetic analysis revealed that our screen identified both known cell division genes, and genes that have not previously been identified to be involved in cell division. This novel screening strategy is applicable to a wide range of organisms, including pathogenic bacteria, where cell division genes and regulators are attractive drug targets for antibiotic development.
Collapse
Affiliation(s)
- Catherine Burke
- The ithree Institute, University of Technology, Sydney, New South Wales, Australia.
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Slayden RA, Jackson M, Zucker J, Ramirez MV, Dawson CC, Crew R, Sampson NS, Thomas ST, Jamshidi N, Sisk P, Caspi R, Crick DC, McNeil MR, Pavelka MS, Niederweis M, Siroy A, Dona V, McFadden J, Boshoff H, Lew JM. Updating and curating metabolic pathways of TB. Tuberculosis (Edinb) 2013; 93:47-59. [PMID: 23375378 DOI: 10.1016/j.tube.2012.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 11/25/2012] [Indexed: 01/08/2023]
Abstract
The sequencing of complete genomes has accelerated biomedical research by providing information about the overall coding capacity of bacterial chromosomes. The original TB annotation resulted in putative functional assignment of ∼60% of the genes to specific metabolic functions, however, the other 40% of the encoded ORFs where annotated as conserved hypothetical proteins, hypothetical proteins or encoding proteins of unknown function. The TB research community is now at the beginning of the next phases of post-genomics; namely reannotation and functional characterization by targeted experimentation. Arguably, this is the most significant time for basic microbiology in recent history. To foster basic TB research, the Tuberculosis Community Annotation Project (TBCAP) jamboree exercise began the reannotation effort by providing additional information for previous annotations, and refining and substantiating the functional assignment of ORFs and genes within metabolic pathways. The overall goal of the TBCAP 2012 exercise was to gather and compile various data types and use this information with oversight from the scientific community to provide additional information to support the functional annotations of encoding genes. Another objective of this effort was to standardize the publicly accessible Mycobacterium tuberculosis reference sequence and its annotation. The greatest benefit of functional annotation information of genome sequence is that it fuels TB research for drug discovery, diagnostics, vaccine development and epidemiology.
Collapse
|
24
|
Joyce G, Williams KJ, Robb M, Noens E, Tizzano B, Shahrezaei V, Robertson BD. Cell division site placement and asymmetric growth in mycobacteria. PLoS One 2012; 7:e44582. [PMID: 22970255 PMCID: PMC3438161 DOI: 10.1371/journal.pone.0044582] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 08/08/2012] [Indexed: 01/12/2023] Open
Abstract
Mycobacteria are members of the actinomycetes that grow by tip extension and lack apparent homologues of the known cell division regulators found in other rod-shaped bacteria. Previous work using static microscopy on dividing mycobacteria led to the hypothesis that these cells can grow and divide asymmetrically, and at a wide range of sizes, in contrast to the cell growth and division patterns observed in the model rod-shaped organisms. In this study, we test this hypothesis using live-cell time-lapse imaging of dividing Mycobacterium smegmatis labelled with fluorescent PBP1a, to probe peptidoglycan synthesis and label the cell septum. We demonstrate that the new septum is placed accurately at mid-cell, and that the asymmetric division observed is a result of differential growth from the cell tips, with a more than 2-fold difference in growth rate between fast and slow growing poles. We also show that the division site is not selected at a characteristic cell length, suggesting this is not an important cue during the mycobacterial cell cycle.
Collapse
Affiliation(s)
- Graham Joyce
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College, London, United Kingdom
| | - Kerstin J. Williams
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College, London, United Kingdom
| | - Matthew Robb
- Department of Mathematics, Imperial College, London, United Kingdom
| | - Elke Noens
- European Molecular Biology Laboratory, Hamburg, Germany
| | | | - Vahid Shahrezaei
- Department of Mathematics, Imperial College, London, United Kingdom
| | - Brian D. Robertson
- MRC Centre for Molecular Bacteriology and Infection, Department of Medicine, Imperial College, London, United Kingdom
- * E-mail:
| |
Collapse
|
25
|
Vadrevu IS, Lofton H, Sarva K, Blasczyk E, Plocinska R, Chinnaswamy J, Madiraju M, Rajagopalan M. ChiZ levels modulate cell division process in mycobacteria. Tuberculosis (Edinb) 2011; 91 Suppl 1:S128-35. [PMID: 22094151 DOI: 10.1016/j.tube.2011.10.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously shown that expression of chiZ (Rv2719c), encoding a cell wall hydrolase, is upregulated in response to DNA damaging agents and exposure to cephalexin. Furthermore, increased levels of ChiZ lead to decreased viability, loss of membrane integrity and defects in FtsZ-GFP localization and cell division. We now show that ChiZ N'-terminal 110 amino acid region, containing the cell wall hydrolase activity, is sufficient to modulate FtsZ-GFP localization. Further, we found that FtsZ-GFP rings are stabilized in a chiZ deletion strain indicating that ChiZ activity regulates FtsZ assembly. Overexpression of ftsZ did not reverse the reduction in viability caused by overproduction of ChiZ indicating that ChiZ neither interacts with nor directly influences FtsZ assembly. Bacterial two-hybrid assays revealed that ChiZ interacts with FtsI and FtsQ, two other septasomal proteins, but not with FtsZ. Finally, we show that ChiZ is not required for virulence of Mycobacterium tuberculosis in murine macrophages and mice. Our data suggest that optimal levels and activity of the cell wall hydrolase ChiZ are required for regulated cell division in mycobacteria.
Collapse
Affiliation(s)
- Indumathi S Vadrevu
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, USA
| | | | | | | | | | | | | | | |
Collapse
|