1
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Chong TN, Shapiro L. Bacterial cell differentiation enables population level survival strategies. mBio 2024; 15:e0075824. [PMID: 38771034 PMCID: PMC11237816 DOI: 10.1128/mbio.00758-24] [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] [Indexed: 05/22/2024] Open
Abstract
Clonal reproduction of unicellular organisms ensures the stable inheritance of genetic information. However, this means of reproduction lacks an intrinsic basis for genetic variation, other than spontaneous mutation and horizontal gene transfer. To make up for this lack of genetic variation, many unicellular organisms undergo the process of cell differentiation to achieve phenotypic heterogeneity within isogenic populations. Cell differentiation is either an inducible or obligate program. Induced cell differentiation can occur as a response to a stimulus, such as starvation or host cell invasion, or it can be a stochastic process. In contrast, obligate cell differentiation is hardwired into the organism's life cycle. Whether induced or obligate, bacterial cell differentiation requires the activation of a signal transduction pathway that initiates a global change in gene expression and ultimately results in a morphological change. While cell differentiation is considered a hallmark in the development of multicellular organisms, many unicellular bacteria utilize this process to implement survival strategies. In this review, we describe well-characterized cell differentiation programs to highlight three main survival strategies used by bacteria capable of differentiation: (i) environmental adaptation, (ii) division of labor, and (iii) bet-hedging.
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Affiliation(s)
- Trisha N Chong
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Lucy Shapiro
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, USA
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2
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Aitken JM, Aitken JE, Agrawal G. Mycobacterium avium ssp. paratuberculosis and Crohn's Disease-Diagnostic Microbiological Investigations Can Inform New Therapeutic Approaches. Antibiotics (Basel) 2024; 13:158. [PMID: 38391544 PMCID: PMC10886072 DOI: 10.3390/antibiotics13020158] [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: 12/04/2023] [Revised: 01/24/2024] [Accepted: 02/03/2024] [Indexed: 02/24/2024] Open
Abstract
Mycobacterium avium ssp. paratuberculosis (MAP) is the cause of Johne's disease (JD), which is a chronic infectious gastrointestinal disease of ruminants and is often fatal. In humans, MAP has been associated with Crohn's disease (CD) for over a century, without conclusive evidence of pathogenicity. Numerous researchers have contributed to the subject, but there is still a need for evidence of the causation of CD by MAP. An infectious aetiology in CD that is attributable to MAP can only be proven by bacteriological investigations. There is an urgency in resolving this question due to the rising global incidence rates of CD. Recent papers have indicated the "therapeutic ceiling" may be close in the development of new biologics. Clinical trial outcomes have demonstrated mild or inconsistent improvements in therapeutic interventions over the last decades when compared with placebo. The necessity to revisit therapeutic options for CD is becoming more urgent and a renewed focus on causation is essential for progress in identifying new treatment options. This manuscript discusses newer interventions, such as vaccination, FMT, dietary remediation and gut microbiome regulation, that will become more relevant as existing therapeutic options expire. Revisiting the MAP theory as a potential infectious cause of CD, rather than the prevailing concept of an "aberrant immune response" will require expanding the current therapeutic programme to include potential new alternatives, and combinations of existing treatments. To advance research on MAP in humans, it is essential for microbiologists and medical scientists to microscopically detect CWDM and to biologically amplify the growth by directed culture.
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Affiliation(s)
- John M Aitken
- Otakaro Pathways Ltd., Innovation Park, Christchurch 7675, New Zealand
| | - Jack E Aitken
- Otakaro Pathways Ltd., Innovation Park, Christchurch 7675, New Zealand
| | - Gaurav Agrawal
- Division of Diabetes & Nutritional Sciences, Franklin-Wilkins Building, King's College London, London SE1 9NH, UK
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3
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Boopathi S, Ramasamy S, Haridevamuthu B, Murugan R, Veerabadhran M, Jia AQ, Arockiaraj J. Intercellular communication and social behaviors in mycobacteria. Front Microbiol 2022; 13:943278. [PMID: 36177463 PMCID: PMC9514802 DOI: 10.3389/fmicb.2022.943278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Cell-to-cell communication is a fundamental process of bacteria to exert communal behaviors. Sputum samples of patients with cystic fibrosis have often been observed with extensive mycobacterial genetic diversity. The emergence of heterogenic mycobacterial populations is observed due to subtle changes in their morphology, gene expression level, and distributive conjugal transfer (DCT). Since each subgroup of mycobacteria has different hetero-resistance, they are refractory against several antibiotics. Such genetically diverse mycobacteria have to communicate with each other to subvert the host immune system. However, it is still a mystery how such heterogeneous strains exhibit synchronous behaviors for the production of quorum sensing (QS) traits, such as biofilms, siderophores, and virulence proteins. Mycobacteria are characterized by division of labor, where distinct sub-clonal populations contribute to the production of QS traits while exchanging complimentary products at the community level. Thus, active mycobacterial cells ensure the persistence of other heterogenic clonal populations through cooperative behaviors. Additionally, mycobacteria are likely to establish communication with neighboring cells in a contact-independent manner through QS signals. Hence, this review is intended to discuss our current knowledge of mycobacterial communication. Understanding mycobacterial communication could provide a promising opportunity to develop drugs to target key pathways of mycobacteria.
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Affiliation(s)
- Seenivasan Boopathi
- Key Laboratory of Tropical Biological Resources of Ministry Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Subbiah Ramasamy
- Department of Biochemistry, Cardiac Metabolic Disease Laboratory, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - B. Haridevamuthu
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Raghul Murugan
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India
| | - Maruthanayagam Veerabadhran
- Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre Facilities, Kalpakkam, Tamil Nadu, India
| | - Ai-Qun Jia
- Key Laboratory of Tropical Biological Resources of Ministry Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China
- *Correspondence: Ai-Qun Jia
| | - Jesu Arockiaraj
- Department of Biotechnology, College of Science and Humanities, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India
- Jesu Arockiaraj ;
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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.
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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.
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A Feedback Regulatory Loop Containing McdR and WhiB2 Controls Cell Division and DNA Repair in Mycobacteria. mBio 2022; 13:e0334321. [PMID: 35357209 PMCID: PMC9040748 DOI: 10.1128/mbio.03343-21] [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] [Indexed: 11/20/2022] Open
Abstract
Cell division must be coordinated with DNA repair, which is strictly regulated in response to different drugs and environmental stresses in bacteria. However, the mechanisms by which mycobacteria orchestrate these two processes remain largely uncharacterized. Here, we report a regulatory loop between two essential mycobacterial regulators, McdR (Rv1830) and WhiB2, in coordinating the processes of cell division and DNA repair. McdR inhibits cell division-associated whiB2 expression by binding to the AATnACAnnnnTGTnATT motif in the promoter region. Furthermore, McdR overexpression simultaneously activates imuAB and dnaE2 expression to promote error-prone DNA repair, which facilitates genetic adaptation to stress conditions. Through a feedback mechanism, WhiB2 activates mcdR expression by binding to the cGACACGc motif in the promoter region. Importantly, analyses of mutations in clinical Mycobacterium tuberculosis strains indicate that disruption of this McdR-WhiB2 feedback regulatory loop influences expression of both cell growth- and DNA repair-associated genes, which further supports the contribution of McdR-WhiB2 regulatory loop in regulating mycobacterial cell growth and drug resistance. This highly conserved feedback regulatory loop provides fresh insight into the link between mycobacterial cell growth control and stress responses. IMPORTANCE Drug-resistant M. tuberculosis poses a threat to the control and prevention of tuberculosis (TB) worldwide. Thus, there is a need to identify the mechanisms enabling M. tuberculosis to adapt and grow under drug-induced stress. Rv1830 has been shown to be associated with drug resistance in M. tuberculosis, but its mechanisms have not yet been elucidated. Here, we reveal a regulatory role of Rv1830, which coordinates cell division and DNA repair in mycobacteria, and rename it McdR (mycobacterial cell division regulator). An increase in McdR levels represses the expression of cell division-associated whiB2 but activates the DNA repair-associated, error-prone enzymes ImuA/B and DnaE2, which in turn facilitates adaptation to stress responses and drug resistance. Furthermore, WhiB2 activates the transcription of mcdR to form a conserved regulatory loop. These data provide new insights into the mechanisms controlling mycobacterial cell growth and stress responses.
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Kieswetter NS, Ozturk M, Jones SS, Senzani S, Chengalroyen MD, Brombacher F, Kana B, Guler R. Deletion of N-acetylmuramyl-L-alanine amidases alters the host immune response to Mycobacterium tuberculosis infection. Virulence 2021; 12:1227-1238. [PMID: 33980132 PMCID: PMC8128173 DOI: 10.1080/21505594.2021.1914448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Peptidoglycan (PG), a heteropolysaccharide component of the mycobacterial cell wall can be shed during tuberculosis infection with immunomodulatory consequences. As such, changes in PG structure are expected to have important implications on disease progression and host responses during infection with Mycobacterium tuberculosis. Mycobacterial amidases have important roles in remodeling of PG during cell division and are implicated in susceptibility to antibiotics. However, their role in modulating host immunity remains unknown. We assessed the bacterial burden and host immune responses to M. tuberculosis mutants defective for either one of two PG N-acetylmuramyl-L-alanine amidases, Ami1 and Ami4, in bone marrow-derived macrophages (BMDM) and C57BL/6 mice. In infected BMDM, the single deletion of both genes resulted in increased proinflammatory cytokine responses. In mice, infection with the Δami1 mutant led to differential induction of pro-inflammatory cytokines and chemokines, decreased cellular recruitment and reduced lung pathology during the acute phase of the infection. While increased proinflammatory cytokines production was observed in BMDM infected with the Δami4 mutant, these effects did not prevail in mice. Infection using the Δami1 and Δami4 Mtb mutants showed that these genes are dispensable for intracellular mycobacterial growth in macrophages and mycobacterial burden in mice. These findings suggest that both Ami1 and Ami4 in M. tuberculosis are not essential for mycobacterial growth within the host. In summary, we show that amidases are important for modulating host immunity during Mtb infection in murine macrophages and mice.
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Affiliation(s)
- Nathan Scott Kieswetter
- Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Pathology, Institute of Infectious Diseases and Molecular Medicine (IDM), Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Mumin Ozturk
- Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Pathology, Institute of Infectious Diseases and Molecular Medicine (IDM), Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Shelby-Sara Jones
- Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Pathology, Institute of Infectious Diseases and Molecular Medicine (IDM), Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Sibusiso Senzani
- DST/NRF Centre of Excellence for Biomedical TB Research, Faculty of Health Sciences, National Health Laboratory Service, University of the Witwatersrand, Johannesburg, South Africa
| | - Melissa Dalcina Chengalroyen
- DST/NRF Centre of Excellence for Biomedical TB Research, Faculty of Health Sciences, National Health Laboratory Service, University of the Witwatersrand, Johannesburg, South Africa
| | - Frank Brombacher
- Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Pathology, Institute of Infectious Diseases and Molecular Medicine (IDM), Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Bavesh Kana
- DST/NRF Centre of Excellence for Biomedical TB Research, Faculty of Health Sciences, National Health Laboratory Service, University of the Witwatersrand, Johannesburg, South Africa
| | - Reto Guler
- Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Department of Pathology, Institute of Infectious Diseases and Molecular Medicine (IDM), Division of Immunology and South African Medical Research Council (SAMRC) Immunology of Infectious Diseases, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.,Wellcome Centre for Infectious Diseases Research in Africa (CIDRI-Africa), Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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7
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Hicks A, Escobar CA, Cross TA, Zhou HX. Sequence-Dependent Correlated Segments in the Intrinsically Disordered Region of ChiZ. Biomolecules 2020; 10:biom10060946. [PMID: 32585849 PMCID: PMC7355643 DOI: 10.3390/biom10060946] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/12/2022] Open
Abstract
How sequences of intrinsically disordered proteins (IDPs) code for their conformational dynamics is poorly understood. Here, we combined NMR spectroscopy, small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulations to characterize the conformations and dynamics of ChiZ1-64. MD simulations, first validated by SAXS and secondary chemical shift data, found scant α-helices or β-strands but a considerable propensity for polyproline II (PPII) torsion angles. Importantly, several blocks of residues (e.g., 11–29) emerge as “correlated segments”, identified by their frequent formation of PPII stretches, salt bridges, cation-π interactions, and sidechain-backbone hydrogen bonds. NMR relaxation experiments showed non-uniform transverse relaxation rates (R2s) and nuclear Overhauser enhancements (NOEs) along the sequence (e.g., high R2s and NOEs for residues 11–14 and 23–28). MD simulations further revealed that the extent of segmental correlation is sequence-dependent; segments where internal interactions are more prevalent manifest elevated “collective” motions on the 5–10 ns timescale and suppressed local motions on the sub-ns timescale. Amide proton exchange rates provides corroboration, with residues in the most correlated segment exhibiting the highest protection factors. We propose the correlated segment as a defining feature for the conformations and dynamics of IDPs.
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Affiliation(s)
- Alan Hicks
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA; (A.H.); (C.A.E.)
- Department of Physics, Florida State University, Tallahassee, FL 32306, USA
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Cristian A. Escobar
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA; (A.H.); (C.A.E.)
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
| | - Timothy A. Cross
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA; (A.H.); (C.A.E.)
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, USA
- Correspondence: (T.A.C.); (H.-X.Z.)
| | - Huan-Xiang Zhou
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
- Correspondence: (T.A.C.); (H.-X.Z.)
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8
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Mycobacterium smegmatis MSMEG_0129 is a nutrition-associated regulator that interacts with CarD and ClpP2. Int J Biochem Cell Biol 2020; 124:105763. [PMID: 32389745 DOI: 10.1016/j.biocel.2020.105763] [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] [Received: 10/01/2019] [Revised: 04/14/2020] [Accepted: 04/29/2020] [Indexed: 12/16/2022]
Abstract
Mycobacterium smegmatis MSMEG_0129 and Rv0164, its homologue in Mycobacterium tuberculosis, are single START-domain proteins essential for bacterial growth and survival, but their biochemical activities and biological roles remain undetermined. Here, we probed the possible functions of MSMEG_0129 and its underlying mechanisms by determining its cellular location, searching for its interaction partners and monitoring its transcription profile. MSMEG_0129, and Rv0164 by extension, were found to be cytosolic proteins rather than secreted components as previously understood. Increases in MSMEG_0129 expression at physiological levels accelerated bacterial growth in a proportional manner, but additional growth acceleration was not observed when MSMEG_0129 was overexpressed up to 20 fold. MSMEG_0129 is a short-lived protein, unstable at both the mRNA and protein levels. Co-IP and GST pull-down assays showed that MSMEG_0129 interacts with the ClpP2 protease and a global transcription factor, CarD, their expression being correlated with that of MSMEG_0129. Nutrient deficiency led to the downregulation of MSMEG_0129 but upregulation of CarD. However, in the context of constitutive MSMEG_0129 overexpression under nutrient-rich or starvation conditions, the mRNA level of CarD was reduced 3 fold. Conversely, expression of ClpP2 decreased with MSMEG_0129 downregulation under starvation conditions, but increased 4-8 fold when MSMEG_0129 was overexpressed. Our data suggest that MSMEG_0129, and Rv0164 by analogy, are likely to be nutrition sensing factors that regulate mycobacterial growth and may be involved in signal transfer under nutrient deficiency, possibly via physical and regulatory interactions with CarD and ClpP2.
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9
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Pietersen RD, du Preez I, Loots DT, van Reenen M, Beukes D, Leisching G, Baker B. Tween 80 induces a carbon flux rerouting in Mycobacterium tuberculosis. J Microbiol Methods 2019; 170:105795. [PMID: 31785333 DOI: 10.1016/j.mimet.2019.105795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 02/06/2023]
Abstract
As a means to increase the growth rate and reduce aggregation, Tween 80 is routinely added to growth media during mycobacterial culturing. This detergent has, however, been associated with causing alterations to the morphology, pathogenicity and virulence of these bacteria. In an attempt to better understand the underlying mechanism of these alterations, we investigated the effect of Tween 80 on the metabolomes of a M. tuberculosis lab strain (H37Rv) and multidrug-resistant clinical strain (R179), using GC-GCxTOF-MS metabolomics. The metabolite markers identified indicated Tween 80-induced disparities in the central carbon metabolism of both strains, with an upregulation in the glyoxylate cycle, glucogenogenesis and the pentose phosphate pathway. The results also signified an increased production of mycobacterial biosynthetic precursors such as triacylglycerols, proteinogenic amino acids and nucleotide precursors, in the presence of the detergent. Collectively, these metabolome variations mimic the phenotypic changes observed when M. tuberculosis is grown in vivo, in a lipid rich environment. However, in addition to the increased availability of oleic acid as a carbon source from Tween 80, the observed variations, and the morphological changes associated with the detergent, could also be a result of an overall stress response in these bacteria. This study is the first to identify specific metabolome variations related to the addition of Tween 80 to the growth media during M. tuberculosis culturing. The consideration of these results during the method development and data interpretation phases of future metabolomics investigations will improve the quality of the analyses as well as the credibility of potential research outcomes. These results will also assist in the interpretation of research questions specifically aimed at aspects of mycobacterial metabolism, even when using other methodologies such as transcriptomics or fluxomics.
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Affiliation(s)
- Ray-Dean Pietersen
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
| | - Ilse du Preez
- Human Metabolomics, North-West University, Potchefstroom, South Africa.
| | - Du Toit Loots
- Human Metabolomics, North-West University, Potchefstroom, South Africa.
| | - Mari van Reenen
- Human Metabolomics, North-West University, Potchefstroom, South Africa.
| | - Derylize Beukes
- Human Metabolomics, North-West University, Potchefstroom, South Africa.
| | - Gina Leisching
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
| | - Bienyameen Baker
- DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
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10
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Wang R, Kreutzfeldt K, Botella H, Vaubourgeix J, Schnappinger D, Ehrt S. Persistent Mycobacterium tuberculosis infection in mice requires PerM for successful cell division. eLife 2019; 8:49570. [PMID: 31751212 PMCID: PMC6872210 DOI: 10.7554/elife.49570] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/11/2019] [Indexed: 01/09/2023] Open
Abstract
The ability of Mycobacterium tuberculosis (Mtb) to persist in its host is central to the pathogenesis of tuberculosis, yet the underlying mechanisms remain incompletely defined. PerM, an integral membrane protein, is required for persistence of Mtb in mice. Here, we show that perM deletion caused a cell division defect specifically during the chronic phase of mouse infection, but did not affect Mtb’s cell replication during acute infection. We further demonstrate that PerM is required for cell division in chronically infected mice and in vitro under host-relevant stresses because it is part of the mycobacterial divisome and stabilizes the essential divisome protein FtsB. These data highlight the importance of sustained cell division for Mtb persistence, define condition-specific requirements for cell division and reveal that survival of Mtb during chronic infection depends on a persistence divisome.
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Affiliation(s)
- Ruojun Wang
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, United States.,Immunology and Microbial Pathogenesis Graduate Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United States
| | - Kaj Kreutzfeldt
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, United States
| | - Helene Botella
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, United States
| | - Julien Vaubourgeix
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, United States
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, United States
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, United States.,Immunology and Microbial Pathogenesis Graduate Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United States
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11
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Chromosomally Encoded hok-sok Toxin-Antitoxin System in the Fire Blight Pathogen Erwinia amylovora: Identification and Functional Characterization. Appl Environ Microbiol 2019; 85:AEM.00724-19. [PMID: 31101613 DOI: 10.1128/aem.00724-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 05/08/2019] [Indexed: 12/28/2022] Open
Abstract
Toxin-antitoxin (TA) systems are genetic elements composed of a protein toxin and a counteracting antitoxin that is either a noncoding RNA or protein. In type I TA systems, the antitoxin is a noncoding small RNA (sRNA) that base pairs with the cognate toxin mRNA interfering with its translation. Although type I TA systems have been extensively studied in Escherichia coli and a few human or animal bacterial pathogens, they have not been characterized in plant-pathogenic bacteria. In this study, we characterized a chromosomal locus in the plant pathogen Erwinia amylovora Ea1189 that is homologous to the hok-sok type I TA system previously identified in the Enterobacteriaceae-restricted plasmid R1. Phylogenetic analysis indicated that the chromosomal location of the hok-sok locus is, thus far, unique to E. amylovora We demonstrated that ectopic overexpression of hok is highly toxic to E. amylovora and that the sRNA sok reversed the toxicity of hok through mok, a reading frame presumably translationally coupled with hok We also identified the region that is essential for maintenance of the main toxicity of Hok. Through a hok-sok deletion mutant (Ea1189Δhok-sok), we determined the contribution of the hok-sok locus to cellular growth, micromorphology, and catalase activity. Combined, our findings indicate that the hok-sok TA system, besides being potentially self-toxic, provides fitness advantages to E. amylovora IMPORTANCE Bacterial toxin-antitoxin systems have received great attention because of their potential as targets for antimicrobial development and as tools for biotechnology. Erwinia amylovora, the causal agent of fire blight disease on pome fruit trees, is a major plant-pathogenic bacterium. In this study, we identified and functionally characterized a unique chromosomally encoded hok-sok toxin-antitoxin system in E. amylovora that resembles the plasmid-encoded copies of this system in other Enterobacteriaceae This study of a type I toxin-antitoxin system in a plant-pathogenic bacterium provides the basis to further understand the involvement of toxin-antitoxin systems during infection by a plant-pathogenic bacterium. The new linkage between the hok-sok toxin-antitoxin system and the catalase-mediated oxidative stress response leads to additional considerations of targeting this system for antimicrobial development.
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Ha SI, Park KG, Suk HS, Shin JS, Shin DP, Kwon MO, Park YJ. Study on the Growth Factors for Rapidly Cultivating Mycobacteriumspp. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2019. [DOI: 10.15324/kjcls.2019.51.2.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Sung-Il Ha
- Department of Laboratory Medicine, The Catholic University of Korea, Seoul Saint Mary’s Hospital, Seoul, Korea
| | - Kang-Gyun Park
- Department of Laboratory Medicine, The Catholic University of Korea, Seoul Saint Mary’s Hospital, Seoul, Korea
| | - Hyun-Soo Suk
- Department of Laboratory Medicine, The Catholic University of Korea, Seoul Saint Mary’s Hospital, Seoul, Korea
| | - Jeong-Seob Shin
- Department of Laboratory Medicine, The Catholic University of Korea, Seoul Saint Mary’s Hospital, Seoul, Korea
| | - Dong-Pil Shin
- Department of Laboratory Medicine, The Catholic University of Korea, Seoul Saint Mary’s Hospital, Seoul, Korea
| | - Min-O Kwon
- Department of Laboratory Medicine, The Catholic University of Korea, Seoul Saint Mary’s Hospital, Seoul, Korea
| | - Yeon-Joon Park
- Department of Laboratory Medicine, The Catholic University of Korea, College of Medicine, Seoul, Korea
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13
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Ultee E, Ramijan K, Dame RT, Briegel A, Claessen D. Stress-induced adaptive morphogenesis in bacteria. Adv Microb Physiol 2019; 74:97-141. [PMID: 31126537 DOI: 10.1016/bs.ampbs.2019.02.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacteria thrive in virtually all environments. Like all other living organisms, bacteria may encounter various types of stresses, to which cells need to adapt. In this chapter, we describe how cells cope with stressful conditions and how this may lead to dramatic morphological changes. These changes may not only allow harmless cells to withstand environmental insults but can also benefit pathogenic bacteria by enabling them to escape from the immune system and the activity of antibiotics. A better understanding of stress-induced morphogenesis will help us to develop new approaches to combat such harmful pathogens.
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Affiliation(s)
- Eveline Ultee
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Karina Ramijan
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Remus T Dame
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands; Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CE Leiden, the Netherlands
| | - Ariane Briegel
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Dennis Claessen
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
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Gorla P, Plocinska R, Sarva K, Satsangi AT, Pandeeti E, Donnelly R, Dziadek J, Rajagopalan M, Madiraju MV. MtrA Response Regulator Controls Cell Division and Cell Wall Metabolism and Affects Susceptibility of Mycobacteria to the First Line Antituberculosis Drugs. Front Microbiol 2018; 9:2839. [PMID: 30532747 PMCID: PMC6265350 DOI: 10.3389/fmicb.2018.02839] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/05/2018] [Indexed: 11/25/2022] Open
Abstract
The biological processes regulated by the essential response regulator MtrA and the growth conditions promoting its activation in Mycobacterium tuberculosis, a slow grower and pathogen, are largely unknown. Here, using a gain-of-function mutant, MtrAY 102C, which functions in the absence of the cognate MtrB sensor kinase, we show that the MtrA regulon includes several genes involved in the processes of cell division and cell wall metabolism. The expression of selected MtrA targets and intracellular MtrA levels were compromised under replication arrest induced by genetic manipulation and under stress conditions caused by toxic radicals. The loss of the mtrA gene in M. smegmatis, a rapid grower and non-pathogen, produced filamentous cells with branches and bulges, indicating defects in cell division and cell shape. The ΔmtrA mutant was sensitized to rifampicin and vancomycin and became more resistant to isoniazid, the first line antituberculosis drug. Our data are consistent with the proposal that MtrA controls the optimal cell division, cell wall integrity, and susceptibility to some antimycobacterial drugs.
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Affiliation(s)
- Purushotham Gorla
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Renata Plocinska
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Krishna Sarva
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Akash T Satsangi
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Emmanuel Pandeeti
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Robert Donnelly
- Department of Pathology and Laboratory Medicine, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Jaroslaw Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Malini Rajagopalan
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Murty V Madiraju
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
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Lensmire JM, Pratt ZL, Wong ACL, Kaspar CW. Phosphate and carbohydrate facilitate the formation of filamentous Salmonella enterica during osmotic stress. MICROBIOLOGY-SGM 2018; 164:1503-1513. [PMID: 30325297 DOI: 10.1099/mic.0.000731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Salmonella enterica is a human pathogen that can produce filamentous cells in response to environmental stress. The molecular mediators and biosynthetic pathways that contribute to the formation of filamentous cells (>10 µm in length) during osmotic stress are mostly unknown. The comparison of filamentous and non-filamentous cells in this study was aided by the use of a filtration step to separate cell types. Osmotic stress caused an efflux of phosphate from cells, and the addition of phosphate and a carbohydrate to Luria broth with 7 % NaCl (LB-7NaCl) significantly increased the proportion of filamentous cells in the population (58 %). In addition to direct measurements of intracellular and extracellular phosphate concentrations, the relative abundance of the iraP transcript that is induced by phosphate limitation was monitored. Non-filamentous cells had a greater relative abundance of iraP transcript than filamentous cells. IraP also affects the stability of RpoS, which regulates the general stress regulon, and was detected in non-filamentous cells but not filamentous cells. Markers of metabolic pathways for the production of acetyl-CoA (pflB, encoding for pyruvate formate lyase) and fatty acids (fabH) that are essential to membrane biosynthesis were found in greater abundance in filamentous cells than non-filamentous cells. There were no differences in the DNA, protein and biomass levels in filamentous and non-filamentous cells after 48 h of incubation, although the filamentous cells produced significantly (P<0.05) more acetate. This study found that phosphate and carbohydrate enhanced the formation of filamentous cells during osmotic stress, and there were differences in key regulatory elements and markers of metabolic pathways in filamentous and non-filamentous S. enterica.
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Affiliation(s)
- Joshua M Lensmire
- 1Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, USA
| | | | - Amy C L Wong
- 1Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, USA.,3Food Research Institute, University of Wisconsin - Madison, Madison, WI, USA
| | - Charles W Kaspar
- 3Food Research Institute, University of Wisconsin - Madison, Madison, WI, USA.,1Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, USA
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Phenotypic indications of FtsZ inhibition in hok/sok-induced bacterial growth changes and stress response. Microb Pathog 2017; 114:393-401. [PMID: 29233778 DOI: 10.1016/j.micpath.2017.12.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 12/06/2017] [Accepted: 12/08/2017] [Indexed: 11/22/2022]
Abstract
The hok/sok locus has been shown to enhance the growth of bacteria in adverse growth conditions such as high temperature, low starting-culture densities and antibiotic treatment. This is in addition to their well-established plasmid-stabilization effect via post-segregational killing of plasmid-free daughter cells. It delays the onset of growth by prolonging the lag phase of bacterial culture, and increases the rate of exponential growth when growth eventually begins. This enables the cells adapt to the prevailing growth conditions and enhance their survival in stressful conditions. These effects functionally complement defective SOS response mechanism, and appear analogous to the growth effects of FtsZ in the SOS pathway. In this study, the role of FtsZ in the hok/sok-induced changes in bacterial growth and cell division was investigated. Morphologic studies of early growth-phase cultures and cells growing under temperature stress showed elongated cells typical of FtsZ inhibition/deficiency. Both ftsZ silencing and over-expression produced comparable growth effects in control cells, and altered the growth changes observed otherwise in the hok/sok+ cells. These changes were diminished in SOS-deficient strain containing mutant FtsZ. The involvement of FtsZ in the hok/sok-induced growth changes may be exploited as drug target in host bacteria, which often propagate antibiotic resistance elements.
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Chen X, An L, Fan X, Ju F, Zhang B, Sun H, Xiao J, Hu W, Qu T, Guan L, Tang S, Chen T, Liu G, Dyson P. A trehalose biosynthetic enzyme doubles as an osmotic stress sensor to regulate bacterial morphogenesis. PLoS Genet 2017; 13:e1007062. [PMID: 29084224 PMCID: PMC5685639 DOI: 10.1371/journal.pgen.1007062] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 11/14/2017] [Accepted: 10/09/2017] [Indexed: 11/18/2022] Open
Abstract
The dissacharide trehalose is an important intracellular osmoprotectant and the OtsA/B pathway is the principal pathway for trehalose biosynthesis in a wide range of bacterial species. Scaffolding proteins and other cytoskeletal elements play an essential role in morphogenetic processes in bacteria. Here we describe how OtsA, in addition to its role in trehalose biosynthesis, functions as an osmotic stress sensor to regulate cell morphology in Arthrobacter strain A3. In response to osmotic stress, this and other Arthrobacter species undergo a transition from bacillary to myceloid growth. An otsA null mutant exhibits constitutive myceloid growth. Osmotic stress leads to a depletion of trehalose-6-phosphate, the product of the OtsA enzyme, and experimental depletion of this metabolite also leads to constitutive myceloid growth independent of OtsA function. In vitro analyses indicate that OtsA can self-assemble into protein networks, promoted by trehalose-6-phosphate, a property that is not shared by the equivalent enzyme from E. coli, despite the latter’s enzymatic activity when expressed in Arthrobacter. This, and the localization of the protein in non-stressed cells at the mid-cell and poles, indicates that OtsA from Arthrobacter likely functions as a cytoskeletal element regulating cell morphology. Recruiting a biosynthetic enzyme for this morphogenetic function represents an intriguing adaptation in bacteria that can survive in extreme environments. For free living bacteria, little is known about how environmental cues are perceived and translated into changes in cell morphology. Here we describe how a biosynthetic enzyme involved in synthesis of an important intracellular osmoprotectant doubles as an osmotic stress sensing morphogenetic protein. This protein is involved in an adaptive response involving a growth transition in stress-tolerant bacteria, from growing as individual cells to forming non-separating branched cell aggregates. We demonstrate that the protein can self-assemble into large networks, consistent with its role as a morphogenetic protein, this assembly process being promoted by a metabolic product of the enzyme. Depletion of either this metabolite or the morphogenetic protein results in the inability of the bacteria to grow as individual cells in conditions of low osmolarity.
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Affiliation(s)
- Ximing Chen
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Lanzhou, Gansu, China
| | - Lizhe An
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
- * E-mail: (PD); (LA)
| | - Xiaochuan Fan
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
| | - Furong Ju
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
| | - Binglin Zhang
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Lanzhou, Gansu, China
| | - Haili Sun
- School of Chemistry and Environmental Science, Lanzhou City University, Lanzhou, Gansu, China
| | - Jianxi Xiao
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry & Chemical Engineering, Lanzhou University, Lanzhou, Gansu, China
| | - Wei Hu
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
| | - Tao Qu
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
| | - Liping Guan
- State Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, Lanzhou University, Lanzhou, Gansu, China
| | - Shukun Tang
- Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education and Laboratory for Conservation and Utilization of Bio-Resources, Yunnan Institute of Microbiology, Yunnan University, Kunming, China
| | - Tuo Chen
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Lanzhou, Gansu, China
| | - Guangxiu Liu
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering of Gansu Province, Lanzhou, Gansu, China
| | - Paul Dyson
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
- * E-mail: (PD); (LA)
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Escherichia coli responds to environmental changes using enolasic degradosomes and stabilized DicF sRNA to alter cellular morphology. Proc Natl Acad Sci U S A 2017; 114:E8025-E8034. [PMID: 28874523 DOI: 10.1073/pnas.1703731114] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli RNase E is an essential enzyme that forms multicomponent ribonucleolytic complexes known as "RNA degradosomes." These complexes consist of four major components: RNase E, PNPase, RhlB RNA helicase, and enolase. However, the role of enolase in the RNase E/degradosome is not understood. Here, we report that presence of enolase in the RNase E/degradosome under anaerobic conditions regulates cell morphology, resulting in Ecoli MG1655 cell filamentation. Under anaerobic conditions, enolase bound to the RNase E/degradosome stabilizes the small RNA (sRNA) DicF, i.e., the inhibitor of the cell division gene ftsZ, through chaperon protein Hfq-dependent regulation. RNase E/enolase distribution changes from membrane-associated patterns under aerobic to diffuse patterns under anaerobic conditions. When the enolase-RNase E/degradosome interaction is disrupted, the anaerobically induced characteristics disappear. We provide a mechanism by which Ecoli uses enolase-bound degradosomes to switch from rod-shaped to filamentous form in response to anaerobiosis by regulating RNase E subcellular distribution, RNase E enzymatic activity, and the stability of the sRNA DicF required for the filamentous transition. In contrast to Ecoli nonpathogenic strains, pathogenic Ecoli strains predominantly have multiple copies of sRNA DicF in their genomes, with cell filamentation previously being linked to bacterial pathogenesis. Our data suggest a mechanism for bacterial cell filamentation during infection under anaerobic conditions.
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19
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van Teeseling MCF, de Pedro MA, Cava F. Determinants of Bacterial Morphology: From Fundamentals to Possibilities for Antimicrobial Targeting. Front Microbiol 2017; 8:1264. [PMID: 28740487 PMCID: PMC5502672 DOI: 10.3389/fmicb.2017.01264] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/23/2017] [Indexed: 12/11/2022] Open
Abstract
Bacterial morphology is extremely diverse. Specific shapes are the consequence of adaptive pressures optimizing bacterial fitness. Shape affects critical biological functions, including nutrient acquisition, motility, dispersion, stress resistance and interactions with other organisms. Although the characteristic shape of a bacterial species remains unchanged for vast numbers of generations, periodical variations occur throughout the cell (division) and life cycles, and these variations can be influenced by environmental conditions. Bacterial morphology is ultimately dictated by the net-like peptidoglycan (PG) sacculus. The species-specific shape of the PG sacculus at any time in the cell cycle is the product of multiple determinants. Some morphological determinants act as a cytoskeleton to guide biosynthetic complexes spatiotemporally, whereas others modify the PG sacculus after biosynthesis. Accumulating evidence supports critical roles of morphogenetic processes in bacteria-host interactions, including pathogenesis. Here, we review the molecular determinants underlying morphology, discuss the evidence linking bacterial morphology to niche adaptation and pathogenesis, and examine the potential of morphological determinants as antimicrobial targets.
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Affiliation(s)
- Muriel C F van Teeseling
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
| | - Miguel A de Pedro
- Centro de Biología Molecular "Severo Ochoa" - Consejo Superior de Investigaciones Científicas, Universidad Autónoma de MadridMadrid, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden
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20
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Abstract
Faithful replication and maintenance of the genome are essential to the ability of any organism to survive and propagate. For an obligate pathogen such as Mycobacterium tuberculosis that has to complete successive cycles of transmission, infection, and disease in order to retain a foothold in the human population, this requires that genome replication and maintenance must be accomplished under the metabolic, immune, and antibiotic stresses encountered during passage through variable host environments. Comparative genomic analyses have established that chromosomal mutations enable M. tuberculosis to adapt to these stresses: the emergence of drug-resistant isolates provides direct evidence of this capacity, so too the well-documented genetic diversity among M. tuberculosis lineages across geographic loci, as well as the microvariation within individual patients that is increasingly observed as whole-genome sequencing methodologies are applied to clinical samples and tuberculosis (TB) disease models. However, the precise mutagenic mechanisms responsible for M. tuberculosis evolution and adaptation are poorly understood. Here, we summarize current knowledge of the machinery responsible for DNA replication in M. tuberculosis, and discuss the potential contribution of the expanded complement of mycobacterial DNA polymerases to mutagenesis. We also consider briefly the possible role of DNA replication-in particular, its regulation and coordination with cell division-in the ability of M. tuberculosis to withstand antibacterial stresses, including host immune effectors and antibiotics, through the generation at the population level of a tolerant state, or through the formation of a subpopulation of persister bacilli-both of which might be relevant to the emergence and fixation of genetic drug resistance.
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21
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Mathew B, Hobrath JV, Ross L, Connelly MC, Lofton H, Rajagopalan M, Guy RK, Reynolds RC. Screening and Development of New Inhibitors of FtsZ from M. Tuberculosis. PLoS One 2016; 11:e0164100. [PMID: 27768711 PMCID: PMC5074515 DOI: 10.1371/journal.pone.0164100] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/20/2016] [Indexed: 12/14/2022] Open
Abstract
A variety of commercial analogs and a newer series of Sulindac derivatives were screened for inhibition of M. tuberculosis (Mtb) in vitro and specifically as inhibitors of the essential mycobacterial tubulin homolog, FtsZ. Due to the ease of preparing diverse analogs and a favorable in vivo pharmacokinetic and toxicity profile of a representative analog, the Sulindac scaffold may be useful for further development against Mtb with respect to in vitro bacterial growth inhibition and selective activity for Mtb FtsZ versus mammalian tubulin. Further discovery efforts will require separating reported mammalian cell activity from both antibacterial activity and inhibition of Mtb FtsZ. Modeling studies suggest that these analogs bind in a specific region of the Mtb FtsZ polymer that differs from human tubulin and, in combination with a pharmacophore model presented herein, future hybrid analogs of the reported active molecules that more efficiently bind in this pocket may improve antibacterial activity while improving other drug characteristics.
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Affiliation(s)
- Bini Mathew
- Drug Discovery Division, Southern Research Institute, 2000 Ninth Avenue South, Birmingham, Alabama, 35205, United States of America
| | - Judith Varady Hobrath
- Drug Discovery Unit, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom
| | - Larry Ross
- Drug Discovery Division, Southern Research Institute, 2000 Ninth Avenue South, Birmingham, Alabama, 35205, United States of America
| | - Michele C. Connelly
- Dept. Chemical Biology & Therapeutics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, United States of America
| | - Hava Lofton
- The University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, United States of America
| | - Malini Rajagopalan
- The University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, United States of America
| | - R. Kiplin Guy
- Dept. Chemical Biology & Therapeutics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, United States of America
| | - Robert C. Reynolds
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, Alabama, 35294, United States of America
- Division of Hematology and Oncology, The University of Alabama at Birmingham, Birmingham, Alabama, 35294, United States of America
- * E-mail:
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22
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Singh AK, Carette X, Potluri LP, Sharp JD, Xu R, Prisic S, Husson RN. Investigating essential gene function in Mycobacterium tuberculosis using an efficient CRISPR interference system. Nucleic Acids Res 2016; 44:e143. [PMID: 27407107 PMCID: PMC5062980 DOI: 10.1093/nar/gkw625] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 07/02/2016] [Indexed: 12/23/2022] Open
Abstract
Despite many methodological advances that have facilitated investigation of Mycobacterium tuberculosis pathogenesis, analysis of essential gene function in this slow-growing pathogen remains difficult. Here, we describe an optimized CRISPR-based method to inhibit expression of essential genes based on the inducible expression of an enzymatically inactive Cas9 protein together with gene-specific guide RNAs (CRISPR interference). Using this system to target several essential genes of M. tuberculosis, we achieved marked inhibition of gene expression resulting in growth inhibition, changes in susceptibility to small molecule inhibitors and disruption of normal cell morphology. Analysis of expression of genes containing sequences similar to those targeted by individual guide RNAs did not reveal significant off-target effects. Advantages of this approach include the ability to compare inhibited gene expression to native levels of expression, lack of the need to alter the M. tuberculosis chromosome, the potential to titrate the extent of transcription inhibition, and the ability to avoid off-target effects. Based on the consistent inhibition of transcription and the simple cloning strategy described in this work, CRISPR interference provides an efficient approach to investigate essential gene function that may be particularly useful in characterizing genes of unknown function and potential targets for novel small molecule inhibitors.
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Affiliation(s)
- Atul K Singh
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Xavier Carette
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lakshmi-Prasad Potluri
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jared D Sharp
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ranfei Xu
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sladjana Prisic
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Robert N Husson
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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23
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Shen JP, Chou CF. Morphological plasticity of bacteria-Open questions. BIOMICROFLUIDICS 2016; 10:031501. [PMID: 27375812 PMCID: PMC4902820 DOI: 10.1063/1.4953660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/23/2016] [Indexed: 05/08/2023]
Abstract
Morphological plasticity of bacteria is a cryptic phenomenon, by which bacteria acquire adaptive benefits for coping with changing environments. Some environmental cues were identified to induce morphological plasticity, but the underlying molecular mechanisms remain largely unknown. Physical and chemical factors causing morphological changes in bacteria have been investigated and mostly associated with potential pathways linked to the cell wall synthetic machinery. These include starvation, oxidative stresses, predation effectors, antimicrobial agents, temperature stresses, osmotic shock, and mechanical constraints. In an extreme scenario of morphological plasticity, bacteria can be induced to be shapeshifters when the cell walls are defective or deficient. They follow distinct developmental pathways and transform into assorted morphological variants, and most of them would eventually revert to typical cell morphology. It is suggested that phenotypic heterogeneity might play a functional role in the development of morphological diversity and/or plasticity within an isogenic population. Accordingly, phenotypic heterogeneity and inherited morphological plasticity are found to be survival strategies adopted by bacteria in response to environmental stresses. Here, microfluidic and nanofabrication technology is considered to provide versatile solutions to induce morphological plasticity, sort and isolate morphological variants, and perform single-cell analysis including transcriptional and epigenetic profiling. Questions such as how morphogenesis network is modulated or rewired (if epigenetic controls of cell morphogenesis apply) to induce bacterial morphological plasticity could be resolved with the aid of micro-nanofluidic platforms and optimization algorithms, such as feedback system control.
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Staying in Shape: the Impact of Cell Shape on Bacterial Survival in Diverse Environments. Microbiol Mol Biol Rev 2016; 80:187-203. [PMID: 26864431 DOI: 10.1128/mmbr.00031-15] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria display an abundance of cellular forms and can change shape during their life cycle. Many plausible models regarding the functional significance of cell morphology have emerged. A greater understanding of the genetic programs underpinning morphological variation in diverse bacterial groups, combined with assays of bacteria under conditions that mimic their varied natural environments, from flowing freshwater streams to diverse human body sites, provides new opportunities to probe the functional significance of cell shape. Here we explore shape diversity among bacteria, at the levels of cell geometry, size, and surface appendages (both placement and number), as it relates to survival in diverse environments. Cell shape in most bacteria is determined by the cell wall. A major challenge in this field has been deconvoluting the effects of differences in the chemical properties of the cell wall and the resulting cell shape perturbations on observed fitness changes. Still, such studies have begun to reveal the selective pressures that drive the diverse forms (or cell wall compositions) observed in mammalian pathogens and bacteria more generally, including efficient adherence to biotic and abiotic surfaces, survival under low-nutrient or stressful conditions, evasion of mammalian complement deposition, efficient dispersal through mucous barriers and tissues, and efficient nutrient acquisition.
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Wu ML, Dick T. Metabolic flexibility and morphological plasticity in mycobacteria. Future Microbiol 2016; 10:449-52. [PMID: 25865185 DOI: 10.2217/fmb.14.151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Mu-Lu Wu
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, 5 Science Drive 2, Singapore 117545, Republic of Singapore
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Role of Tellurite Resistance Operon in Filamentous Growth of Yersinia pestis in Macrophages. PLoS One 2015; 10:e0141984. [PMID: 26536670 PMCID: PMC4633105 DOI: 10.1371/journal.pone.0141984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/15/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Yersinia pestis initiates infection by parasitism of host macrophages. In response to macrophage infections, intracellular Y. pestis can assume a filamentous cellular morphology which may mediate resistance to host cell innate immune responses. We previously observed the expression of Y. pestis tellurite resistance proteins TerD and TerE from the terZABCDE operon during macrophage infections. Others have observed a filamentous response associated with expression of tellurite resistance operon in Escherichia coli exposed to tellurite. Therefore, in this study we examine the potential role of Y. pestis tellurite resistance operon in filamentous cellular morphology during macrophage infections. PRINCIPAL FINDINGS In vitro treatment of Y. pestis culture with sodium tellurite (Na2TeO3) caused the bacterial cells to assume a filamentous phenotype similar to the filamentous phenotype observed during macrophage infections. A deletion mutant for genes terZAB abolished the filamentous morphologic response to tellurite exposure or intracellular parasitism, but without affecting tellurite resistance. However, a terZABCDE deletion mutant abolished both filamentous morphologic response and tellurite resistance. Complementation of the terZABCDE deletion mutant with terCDE, but not terZAB, partially restored tellurite resistance. When the terZABCDE deletion mutant was complemented with terZAB or terCDE, Y. pestis exhibited filamentous morphology during macrophage infections as well as while these complemented genes were being expressed under an in vitro condition. Further in E. coli, expression of Y. pestis terZAB, but not terCDE, conferred a filamentous phenotype. CONCLUSIONS These findings support the role of Y. pestis terZAB mediation of the filamentous response phenotype; whereas, terCDE confers tellurite resistance. Although the beneficial role of filamentous morphological responses by Y. pestis during macrophage infections is yet to be fully defined, it may be a bacterial adaptive strategy to macrophage associated stresses.
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Kieser KJ, Boutte CC, Kester JC, Baer CE, Barczak AK, Meniche X, Chao MC, Rego EH, Sassetti CM, Fortune SM, Rubin EJ. Phosphorylation of the Peptidoglycan Synthase PonA1 Governs the Rate of Polar Elongation in Mycobacteria. PLoS Pathog 2015; 11:e1005010. [PMID: 26114871 PMCID: PMC4483258 DOI: 10.1371/journal.ppat.1005010] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/07/2015] [Indexed: 01/11/2023] Open
Abstract
Cell growth and division are required for the progression of bacterial infections. Most rod-shaped bacteria grow by inserting new cell wall along their mid-section. However, mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce new cell wall material at their poles. How mycobacteria control this different mode of growth is incompletely understood. Here we find that PonA1, a penicillin binding protein (PBP) capable of transglycosylation and transpeptidation of cell wall peptidoglycan (PG), is a major governor of polar growth in mycobacteria. PonA1 is required for growth of Mycobacterium smegmatis and is critical for M. tuberculosis during infection. In both cases, PonA1’s catalytic activities are both required for normal cell length, though loss of transglycosylase activity has a more pronounced effect than transpeptidation. Mutations that alter the amount or the activity of PonA1 result in abnormal formation of cell poles and changes in cell length. Moreover, altered PonA1 activity results in dramatic differences in antibiotic susceptibility, suggesting that a balance between the two enzymatic activities of PonA1 is critical for survival. We also find that phosphorylation of a cytoplasmic region of PonA1 is required for normal activity. Mutations in a critical phosphorylated residue affect transglycosylase activity and result in abnormal rates of cell elongation. Together, our data indicate that PonA1 is a central determinant of polar growth in mycobacteria, and its governance of cell elongation is required for robust cell fitness during both host-induced and antibiotic stress. Bacterial infections rely on continued bacterial growth. Studying cell growth is particularly important for pathogens such as Mycobacterium tuberculosis that grow differently than model organisms. Unlike Escherichia coli or Bacillus subtilis, which grow by incorporating cell wall material along their body, mycobacteria grow from the pole. It remains unclear how mycobacteria construct and extend their poles. Our work identifies a cell wall synthase, PonA1, as a key determinant of mycobacterial polar growth. PonA1 governs polar growth through two enzymatic activities that build the cell wall’s peptidoglycan (PG); both of these activities are required for normal cell growth. Changes in the amount or activity of PonA1 leads to misplaced cell poles and inhibition of cell proliferation. PonA1 is phosphorylated, an unusual modification for PG synthases. This phosphorylation tunes the rate of cell elongation. Changing PonA1’s regulatory or enzymatic activity impacts the survival of cells in the host or when treated with antibiotics. Our work shows how mycobacterial cell pole construction and cell fitness is governed by a major cell wall synthase; these findings may have implications for other bacteria that elongate from their poles.
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Affiliation(s)
- Karen J. Kieser
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Cara C. Boutte
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Jemila C. Kester
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Christina E. Baer
- Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Amy K. Barczak
- Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Xavier Meniche
- Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Michael C. Chao
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - E. Hesper Rego
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Sarah M. Fortune
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Eric J. Rubin
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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Sikri K, Kumari P, Tyagi JS, Nandi M, Taneja NK, Batra SD. The pleiotropic transcriptional response of Mycobacterium tuberculosis to vitamin C is robust and overlaps with the bacterial response to multiple intracellular stresses. Microbiology (Reading) 2015; 161:739-53. [DOI: 10.1099/mic.0.000049] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/28/2015] [Indexed: 11/18/2022] Open
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Phosphorylation of Mycobacterium tuberculosis ParB participates in regulating the ParABS chromosome segregation system. PLoS One 2015; 10:e0119907. [PMID: 25807382 PMCID: PMC4373775 DOI: 10.1371/journal.pone.0119907] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 02/04/2015] [Indexed: 11/19/2022] Open
Abstract
Here, we present for the first time that Mycobacterium tuberculosis ParB is phosphorylated by several mycobacterial Ser/Thr protein kinases in vitro. ParB and ParA are the key components of bacterial chromosome segregation apparatus. ParB is a cytosolic conserved protein that binds specifically to centromere-like DNA parS sequences and interacts with ParA, a weak ATPase required for its proper localization. Mass spectrometry identified the presence of ten phosphate groups, thus indicating that ParB is phosphorylated on eight threonines, Thr32, Thr41, Thr53, Thr110, Thr195, and Thr254, Thr300, Thr303 as well as on two serines, Ser5 and Ser239. The phosphorylation sites were further substituted either by alanine to prevent phosphorylation or aspartate to mimic constitutive phosphorylation. Electrophoretic mobility shift assays revealed a drastic inhibition of DNA-binding by ParB phosphomimetic mutant compared to wild type. In addition, bacterial two-hybrid experiments showed a loss of ParA-ParB interaction with the phosphomimetic mutant, indicating that phosphorylation is regulating the recruitment of the partitioning complex. Moreover, fluorescence microscopy experiments performed in the surrogate Mycobacterium smegmatis ΔparB strain revealed that in contrast to wild type Mtb ParB, which formed subpolar foci similar to M. smegmatis ParB, phoshomimetic Mtb ParB was delocalized. Thus, our findings highlight a novel regulatory role of the different isoforms of ParB representing a molecular switch in localization and functioning of partitioning protein in Mycobacterium tuberculosis.
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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.
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Klein K, Palarasah Y, Kolmos HJ, Møller-Jensen J, Andersen TE. Quantification of filamentation by uropathogenic Escherichia coli during experimental bladder cell infection by using semi-automated image analysis. J Microbiol Methods 2014; 109:110-6. [PMID: 25546841 DOI: 10.1016/j.mimet.2014.12.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 12/08/2014] [Accepted: 12/23/2014] [Indexed: 01/03/2023]
Abstract
Several rod-shaped pathogens including Escherichia coli, Salmonella spp. and Klebsiella pneumonia are capable of adopting highly filamentous cell shapes under certain circumstances. This phenomenon occurs as a result of continued cell elongation during growth without the usual septation into single rod-shaped cells. Evidence has emerged over the past decade suggesting that this morphological transformation is controlled and reversible and provides selective advantages under certain growth conditions, such as during infection in humans. In order to identify the factors which induce filamentation of bacterial pathogens and study the advantages of bacterial morphological plasticity, methods are needed to accurately quantify changes in bacterial cell shape. In this study, we present a method for quantification of bacterial filamentation based on automatic detection and measurement of bacterial units in focus-stacked microscopy images. Used in combination with a flow-chamber based in vitro cystitis model, we study the factors involved in filament formation by uropathogenic E. coli (UPEC) during infection. The influence of substratum surface, intracellular proliferation and flow media on UPEC filamentation is evaluated. We show that reversible UPEC filamentation during cystitis is not dependent on intracellular infection, which previous studies have suggested. Instead, we find that filamentation can be induced by contact with surfaces, both biological and artificial. Lastly our data indicate that UPEC filamentation is induced by trace-amounts of specific components in urine, rather than being a generic stress-response to high urine salt concentrations. The study shows that the combined methodology is generally useful for investigation of bacterial morphological transitions during cell infection.
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Affiliation(s)
- Kasper Klein
- Research Unit of Clinical Microbiology, University of Southern Denmark, 5000 Odense C, Denmark
| | - Yaseelan Palarasah
- Research Unit of Immunology and Microbiology, University of Southern Denmark, 5000 Odense C, Denmark
| | - Hans Jørn Kolmos
- Research Unit of Clinical Microbiology, University of Southern Denmark, 5000 Odense C, Denmark
| | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Thomas Emil Andersen
- Research Unit of Clinical Microbiology, University of Southern Denmark, 5000 Odense C, Denmark
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Plocinski P, Martinez L, Sarva K, Plocinska R, Madiraju M, Rajagopalan M. Mycobacterium tuberculosis CwsA overproduction modulates cell division and cell wall synthesis. Tuberculosis (Edinb) 2014; 93 Suppl:S21-7. [PMID: 24388644 DOI: 10.1016/s1472-9792(13)70006-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We recently showed that two small membrane proteins of Mycobacterium tuberculosis, CwsA and CrgA, interact with each other, and that loss of CwsA in M. smegmatis is associated with defects in the cell division and cell wall synthesis processes. Here we show that CwsA overproduction also affected growth, cell division and cell shape of M. smegmatis and M. tuberculosis. CwsA overproduction in M. tuberculosis led to increased sensitivity to cefsulodin, a penicillin-binding protein (PBP) 1A/1B targeting beta (β) -lactam, but was unaffected by other β-lactams and vancomycin. A M. smegmatis cwsA overexpressing strain showed bulgy cells, increased fluorescent vancomycin staining and altered localization of Wag31-mCherry fusion protein. However, the levels of phosphorylated Wag31, important for optimal peptidoglycan synthesis and growth in mycobacteria, were not affected. Interestingly, CwsA overproduction in E. coli led to the formation of large rounded cells that eventually lysed whereas the overproduction of FtsZ along with CwsA reversed this phenotype. Together, our results emphasize that optimal levels of CwsA are required for regulated cell wall synthesis, hence maintenance of cell shape, and that CwsA likely interacts with and modulates the activities of other cell wall synthetic components including PBPs.
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Affiliation(s)
- P Plocinski
- Biomedical Research, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA
| | - L Martinez
- Biomedical Research, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA
| | - K Sarva
- Biomedical Research, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA
| | - R Plocinska
- Biomedical Research, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA
| | - M Madiraju
- Biomedical Research, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA
| | - M Rajagopalan
- Biomedical Research, The University of Texas Health Science Center @ Tyler, Tyler, TX 75708, USA.
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Justice SS, Harrison A, Becknell B, Mason KM. Bacterial differentiation, development, and disease: mechanisms for survival. FEMS Microbiol Lett 2014; 360:1-8. [PMID: 25228010 DOI: 10.1111/1574-6968.12602] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/04/2014] [Accepted: 09/11/2014] [Indexed: 12/27/2022] Open
Abstract
Bacteria have the exquisite ability to maintain a precise diameter, cell length, and shape. The dimensions of bacteria size and shape are a classical metric in the distinction of bacterial species. Much of what we know about the particular morphology of any given species is the result of investigations of planktonic cultures. As we explore deeper into the natural habitats of bacteria, it is increasingly clear that bacteria can alter their morphology in response to the environment in which they reside. Specific morphologies are also becoming recognized as advantageous for survival in hostile environments. This is of particular importance in the context of both colonization and infection in the host. There are multiple examples of bacterial pathogens that use morphological changes as a mechanism for evasion of host immune responses and continued persistence. This review will focus on two systems where specific morphological changes are essential for persistence in animal models of human disease. We will also offer insight into the mechanism underlying the morphological changes and how these morphotypes aid in persistence. Additional examples of morphological changes associated with survival will be presented.
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Affiliation(s)
- Sheryl S Justice
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; The Ohio State University School of Medicine, Columbus, OH, USA
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Mycobacterium tuberculosis MtrB sensor kinase interactions with FtsI and Wag31 proteins reveal a role for MtrB distinct from that regulating MtrA activities. J Bacteriol 2014; 196:4120-9. [PMID: 25225272 DOI: 10.1128/jb.01795-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The septal association of Mycobacterium tuberculosis MtrB, the kinase partner of the MtrAB two-component signal transduction system, is necessary for the optimal expression of the MtrA regulon targets, including ripA, fbpB, and ftsI, which are involved in cell division and cell wall synthesis. Here, we show that MtrB, irrespective of its phosphorylation status, interacts with Wag31, whereas only phosphorylation-competent MtrB interacts with FtsI. We provide evidence that FtsI depletion compromises the MtrB septal assembly and MtrA regulon expression; likewise, the absence of MtrB compromises FtsI localization and, possibly, FtsI activity. We conclude from these results that FtsI and MtrB are codependent for their activities and that FtsI functions as a positive modulator of MtrB activation and MtrA regulon expression. In contrast to FtsI, Wag31 depletion does not affect MtrB septal assembly and MtrA regulon expression, whereas the loss of MtrB increased Wag31 localization and the levels of PknA/PknB (PknA/B) serine-threonine protein kinase-mediated Wag31 phosphorylation. Interestingly, we found that FtsI decreased levels of phosphorylated Wag31 (Wag31∼P) and that MtrB interacted with PknA/B. Overall, our results indicate that MtrB interactions with FtsI, Wag31, and PknA/B are required for its optimal localization, MtrA regulon expression, and phosphorylation of Wag31. Our results emphasize a new role for MtrB in cell division and cell wall synthesis distinct from that regulating the MtrA phosphorylation activities.
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Abstract
Mycobacteria are surrounded by a complex multilayered envelope and elongate at the poles. The principles that organize the coordinated addition of chemically diverse cell wall layers during polar extension remain unclear. We show that enzymes mediating the terminal cytosolic steps of peptidoglycan, arabinogalactan, and mycolic acid synthesis colocalize at sites of cell growth or division. The tropomyosin-like protein, DivIVA, is targeted to the negative curvature of the pole, is enriched at the growing end, and determines cell shape from this site. In contrast, cell wall synthetic complexes are concentrated at a distinct subpolar location. When viewed at subdiffraction resolution, new peptidoglycan is deposited at this subpolar site, and inert cell wall covers the DivIVA-marked tip. The differentiation between polar tip and cell wall synthetic complexes is also apparent at the biochemical level. Enzymes that generate mycolate precursors interact with DivIVA, but the final condensation of mycolic acids occurs in a distinct protein complex at the site of nascent cell wall addition. We propose an ultrastructural model of mycobacterial polar growth where new cell wall is added in an annular zone below the cell tip. This model may be broadly applicable to other bacterial and fungal organisms that grow via polar extension.
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36
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Donovan C, Bramkamp M. Cell division in Corynebacterineae. Front Microbiol 2014; 5:132. [PMID: 24782835 PMCID: PMC3989709 DOI: 10.3389/fmicb.2014.00132] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 03/14/2014] [Indexed: 12/02/2022] Open
Abstract
Bacterial cells must coordinate a number of events during the cell cycle. Spatio-temporal regulation of bacterial cytokinesis is indispensable for the production of viable, genetically identical offspring. In many rod-shaped bacteria, precise midcell assembly of the division machinery relies on inhibitory systems such as Min and Noc. In rod-shaped Actinobacteria, for example Corynebacterium glutamicum and Mycobacterium tuberculosis, the divisome assembles in the proximity of the midcell region, however more spatial flexibility is observed compared to Escherichia coli and Bacillus subtilis. Actinobacteria represent a group of bacteria that spatially regulate cytokinesis in the absence of recognizable Min and Noc homologs. The key cell division steps in E. coli and B. subtilis have been subject to intensive study and are well-understood. In comparison, only a minimal set of positive and negative regulators of cytokinesis are known in Actinobacteria. Nonetheless, the timing of cytokinesis and the placement of the division septum is coordinated with growth as well as initiation of chromosome replication and segregation. We summarize here the current knowledge on cytokinesis and division site selection in the Actinobacteria suborder Corynebacterineae.
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Affiliation(s)
- Catriona Donovan
- Department of Biology I, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Marc Bramkamp
- Department of Biology I, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
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HU-induced polymorphous filamentation in fish pathogen Edwardsiella tarda leading to reduced invasion and virulence in zebrafish. Vet Microbiol 2014; 171:165-74. [PMID: 24793099 DOI: 10.1016/j.vetmic.2014.03.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/20/2014] [Accepted: 03/22/2014] [Indexed: 02/03/2023]
Abstract
Edwardsiella tarda is a rod-shaped Gram-negative pathogenic bacterium that causes hemorrhagic septicemia in fish. Nucleoid-associated protein HU is a basic DNA-binding protein with structural specificity in regulating genes expression. In wild-type E. tarda EIB202, HU is composed of two subunits HUα (hupA) and HUβ (hupB), and exists in homodimer or heterodimer forms. Different from the wild-type and ΔhupB mutant, ΔhupA mutant was found to be defective in cell growth, H2S production, acid adaptation, and exhibited abnormal cell division resulting in a filamentous phenotype in log phase bacteria. The qRT-PCR result showed that deletion of hupA significantly up-regulated the transcription levels of recA and sulA, which in turn stimulated RecA-dependent pathway to prevent cell division, resulting in filamentous morphology in E. tarda. Furthermore, the elongated ΔhupA cells showed a striking defect in EPC cell invasion, and the adhesion and internalization rates were reduced to 25% and 27% of the wild-type in log phase cultures. Confocal laser scanning microscopy revealed that filamentous bacteria failed to adhere to and could not be internalized into EPC. When some of the bacteria regained the rod-shape morphology in stationary cultures, the ΔhupA mutants showed increased adhesion and internalization rates into EPC. Moreover, ΔhupA mutant exhibited delayed mortalities (for two days) in zebrafish but the LD50 increased 17 folds. Immunohistochemical analysis showed that ΔhupA mutant reduced proliferation abilities in the muscle, liver and intestine of zebrafish. This study indicates that HU protein and strains morphology play essential roles in the virulence network of E. tarda.
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Claessen D, Rozen DE, Kuipers OP, Søgaard-Andersen L, van Wezel GP. Bacterial solutions to multicellularity: a tale of biofilms, filaments and fruiting bodies. Nat Rev Microbiol 2014; 12:115-24. [PMID: 24384602 DOI: 10.1038/nrmicro3178] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although bacteria frequently live as unicellular organisms, many spend at least part of their lives in complex communities, and some have adopted truly multicellular lifestyles and have abandoned unicellular growth. These transitions to multicellularity have occurred independently several times for various ecological reasons, resulting in a broad range of phenotypes. In this Review, we discuss the strategies that are used by bacteria to form and grow in multicellular structures that have hallmark features of multicellularity, including morphological differentiation, programmed cell death and patterning. In addition, we examine the evolutionary and ecological factors that lead to the wide range of coordinated multicellular behaviours that are observed in bacteria.
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Affiliation(s)
- Dennis Claessen
- 1] Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands. [2]
| | - Daniel E Rozen
- 1] Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands. [2]
| | - Oscar P Kuipers
- 1] Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Linnaeusborg, Nijenborgh 7, 9747 AG, Groningen, The Netherlands. [2] Kluyver Center for Genomics of Industrial Fermentation, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Lotte Søgaard-Andersen
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043, Marburg, Germany
| | - Gilles P van Wezel
- Molecular Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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Tavares LS, Silva CSF, de Souza VC, da Silva VL, Diniz CG, Santos MO. Strategies and molecular tools to fight antimicrobial resistance: resistome, transcriptome, and antimicrobial peptides. Front Microbiol 2013; 4:412. [PMID: 24427156 PMCID: PMC3876575 DOI: 10.3389/fmicb.2013.00412] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 12/15/2013] [Indexed: 11/13/2022] Open
Abstract
The increasing number of antibiotic resistant bacteria motivates prospective research toward discovery of new antimicrobial active substances. There are, however, controversies concerning the cost-effectiveness of such research with regards to the description of new substances with novel cellular interactions, or description of new uses of existing substances to overcome resistance. Although examination of bacteria isolated from remote locations with limited exposure to humans has revealed an absence of antibiotic resistance genes, it is accepted that these genes were both abundant and diverse in ancient living organisms, as detected in DNA recovered from Pleistocene deposits (30,000 years ago). Indeed, even before the first clinical use of antibiotics more than 60 years ago, resistant organisms had been isolated. Bacteria can exhibit different strategies for resistance against antibiotics. New genetic information may lead to the modification of protein structure affecting the antibiotic carriage into the cell, enzymatic inactivation of drugs, or even modification of cellular structure interfering in the drug-bacteria interaction. There are still plenty of new genes out there in the environment that can be appropriated by putative pathogenic bacteria to resist antimicrobial agents. On the other hand, there are several natural compounds with antibiotic activity that may be used to oppose them. Antimicrobial peptides (AMPs) are molecules which are wide-spread in all forms of life, from multi-cellular organisms to bacterial cells used to interfere with microbial growth. Several AMPs have been shown to be effective against multi-drug resistant bacteria and have low propensity to resistance development, probably due to their unique mode of action, different from well-known antimicrobial drugs. These substances may interact in different ways with bacterial cell membrane, protein synthesis, protein modulation, and protein folding. The analysis of bacterial transcriptome may contribute to the understanding of microbial strategies under different environmental stresses and allows the understanding of their interaction with novel AMPs.
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Affiliation(s)
| | - Carolina S. F. Silva
- Department of Microbiology, Immunology and Infectious Diseases, University of Juiz de ForaJuiz de Fora, Brazil
| | | | - Vânia L. da Silva
- Department of Microbiology, Immunology and Infectious Diseases, University of Juiz de ForaJuiz de Fora, Brazil
| | - Cláudio G. Diniz
- Department of Microbiology, Immunology and Infectious Diseases, University of Juiz de ForaJuiz de Fora, Brazil
| | - Marcelo O. Santos
- Department of Biology, University of Juiz de ForaJuiz de Fora, Brazil
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Essentiality of DevR/DosR interaction with SigA for the dormancy survival program in Mycobacterium tuberculosis. J Bacteriol 2013; 196:790-9. [PMID: 24317401 DOI: 10.1128/jb.01270-13] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The DevR/DosR regulator is believed to play a key role in dormancy adaptation mechanisms of Mycobacterium tuberculosis in response to a multitude of gaseous stresses, including hypoxia, which prevails within granulomas. DevR activates transcription by binding to target promoters containing a minimum of two binding sites. The proximal site overlaps with the SigA -35 element, suggesting that DevR-SigA interaction is required for activating transcription. We evaluated the roles of 14 charged residues of DevR in transcriptional activation under hypoxic stress. Seven of the 14 alanine substitution mutants were defective in regulon activation, of which K191A, R197A, and K179A+K168A (designated K179A*) mutants were significantly or completely compromised in DNA binding. Four mutants, namely, E154A, R155A, E178A, and K208A, were activation defective in spite of binding to DNA and were classified as positive-control (pc) mutants. The SigA interaction defect of the E154A and E178A proteins was established by in vitro and in vivo assays and implies that these substitutions lead to an activation defect because they disrupt an interaction(s) with SigA. The relevance of DevR interaction to the transcriptional machinery was further established by the hypoxia survival phenotype displayed by SigA interaction-defective mutants. Our findings demonstrate the role of DevR-SigA interaction in the activation mechanism and in bacterial survival under hypoxia and establish the housekeeping sigma factor SigA as a molecular target of DevR. The interaction of DevR and RNA polymerase suggests a new and novel interceptable molecular interface for future antidormancy strategies for Mycobacterium tuberculosis.
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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.
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Affiliation(s)
| | | | | | | | - Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
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Miallau L, Jain P, Arbing MA, Cascio D, Phan T, Ahn CJ, Chan S, Chernishof I, Maxson M, Chiang J, Jacobs WR, Eisenberg DS. Comparative proteomics identifies the cell-associated lethality of M. tuberculosis RelBE-like toxin-antitoxin complexes. Structure 2013; 21:627-37. [PMID: 23523424 DOI: 10.1016/j.str.2013.02.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 01/06/2023]
Abstract
The Mycobacterium tuberculosis (Mtb) genome encodes approximately 90 toxin-antitoxin protein complexes, including three RelBE family members, which are believed to play a major role in bacterial fitness and pathogenicity. We have determined the crystal structures of Mtb RelBE-2 and RelBE-3, and the structures reveal homologous heterotetramers. Our structures suggest RelE-2, and by extension the closely related RelE-1, use a different catalytic mechanism than RelE-3, because our analysis of the RelE-2 structure predicts additional amino acid residues that are likely to be functionally significant and are missing from analogous positions in the RelE-3 structure. Toxicity assays corroborate our structural findings; overexpression of RelE-3, whose active site is more similar to Escherichia coli YoeB, has limited consequences on bacterial growth, whereas RelE-1 and RelE-2 overexpression results in acute toxicity. Moreover, RelE-2 overexpression results in an elongated cell phenotype in Mycobacterium smegmatis and protects M. tuberculosis against antibiotics, suggesting a different functional role for RelE-2.
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Affiliation(s)
- Linda Miallau
- Howard Hughes Medical Institute and UCLA-DOE Institute for Genomics and Proteomics and Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095-1570, USA
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Unraveling the transcriptional regulatory networks associated to mycobacterial cell wall defective form induction by glycine and lysozyme treatment. Microbiol Res 2013. [DOI: 10.1016/j.micres.2012.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Parti RP, Horbay MA, Liao M, Dillon JAR. Regulation of minD by oxyR in Neisseria gonorrhoeae. Res Microbiol 2013; 164:406-15. [PMID: 23434849 DOI: 10.1016/j.resmic.2013.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
Abstract
In Neisseria gonorrhoeae, cytokinesis involves Escherichia coli homologues of minC, minD and minE which are encoded as part of a min operon. MinD, a 30 kD protein component of the MinC-MinD septum inhibitory complex, together with MinE, mediates cell division site selection. Gonococci mutated in minD display aberrant cytokinesis, abnormal morphology, defective microcolony formation and virulence. minD is 274 bp upstream of oxyR, another min operon gene in N. gonorrhoeae, which encodes a redox-responsive transcriptional regulator implicated in responses to oxidative stress. In this study, we aimed to examine the oxyR-mediated regulation of minD. We observed the cotranscription of oxyR with the minCDE gene cluster. The mutation of oxyR resulted in non-midline formation of the division septum, anomalous DNA segregation, and increased aggregation of bacterial cells. qRT-PCR and Western Blot analysis revealed upregulation of minD in an oxyR mutant as compared to its isogenic wild-type N. gonorrhoeae strain in stationary phase. Furthermore, the exposure to oxidative stress in the form of H2O2 increased MinD expression levels in wild-type N. gonorrhoeae. Using β-galactosidase activity-based promoter assays, we found that oxyR negatively regulates the promoter region (PminD) upstream of minD. Our results demonstrate the involvement of oxyR in cell division and minD expression in N. gonorrhoeae.
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Affiliation(s)
- Rajinder P Parti
- Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK, Canada
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Hossain ST, Mukherjee SK. CdO nanoparticle toxicity on growth, morphology, and cell division in Escherichia coli. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:16614-16622. [PMID: 23137198 DOI: 10.1021/la302872y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This Article deals with the toxicological study of synthesized CdO nanoparticles (NPs) on Escherichia coli . Characterization of the CdO NPs was done by DLS, XRD, TEM, and AFM studies, and the average size of NPs was revealed as 22 ± 3 nm. The NPs showed bactericidal activity against E. coli. When NPs were added at midlog phase of growth, complete growth inhibitory concentration was found as 40 μg/mL. Bacterial cells changed morphological features to filamentous form with increasing CdO NPs exposure time, and thereafter resulted in filamentation-associated clumping. From AFM study, severe damage of the cell surface was found in CdO NPs-treated cells. CdO NPs were found to interfere with the expression level of two conserved cell division components, ftsZ and ftsQ, in E. coli at both transcriptional and translational levels. Interference of CdO NPs in proper septum formation without affecting the nucleoid segregation was also observed in confocal micrographs. The elevated intracellular oxidative stress due to CdO NPs exposure seems to be one of the reasons for the changes in cell morphology and expression of division proteins in E. coli.
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Mycobacterium tuberculosis CwsA interacts with CrgA and Wag31, and the CrgA-CwsA complex is involved in peptidoglycan synthesis and cell shape determination. J Bacteriol 2012; 194:6398-409. [PMID: 23002219 DOI: 10.1128/jb.01005-12] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial cell division and cell wall synthesis are highly coordinated processes involving multiple proteins. Here, we show that Rv0008c, a novel small membrane protein from Mycobacterium tuberculosis, localizes to the poles and on membranes and shows an overall punctate localization throughout the cell. Furthermore, Rv0008c interacts with two proteins, CrgA and Wag31, implicated in peptidoglycan (PG) synthesis in mycobacteria. Deletion of the Rv0008c homolog in M. smegmatis, MSMEG_0023, caused bulged cell poles, formation of rounded cells, and defects in polar localization of Wag31 and cell wall synthesis, with cell wall synthesis measured by the incorporation of the [(14)C]N-acetylglucosamine cell wall precursor. The M. smegmatis MSMEG_0023 crgA double mutant strain showed severe defects in growth, viability, cell wall synthesis, cell shape, and the localization of the FtsZ, FtsI, and Wag31 proteins. The double mutant strain also exhibited increased autolytic activity in the presence of detergents. Because CrgA and Wag31 proteins interact with FtsI individually, we believe that regulated cell wall synthesis and cell shape maintenance require the concerted actions of the CrgA, Rv0008c, FtsI, and Wag31 proteins. We propose that, together, CrgA and Rv0008c, renamed CwsA for cell wall synthesis and cell shape protein A, play crucial roles in septal and polar PG synthesis and help coordinate these processes with the FtsZ-ring assembly in mycobacteria.
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Velayati AA, Farnia P. Division-cycle in Mycobacterium tuberculosis. Int J Mycobacteriol 2012; 1:111-7. [PMID: 26787205 DOI: 10.1016/j.ijmyco.2012.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 08/11/2012] [Indexed: 11/24/2022] Open
Affiliation(s)
- Ali Akbar Velayati
- Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), WHO Collaborating Centre for TB & Lung Diseases, Shahid Beheshti University (Medical Campus), P.O. 19575/154, Darabad, Tehran 19556, Iran; Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parissa Farnia
- Mycobacteriology Research Centre, National Research Institute of Tuberculosis and Lung Disease (NRITLD), WHO Collaborating Centre for TB & Lung Diseases, Shahid Beheshti University (Medical Campus), P.O. 19575/154, Darabad, Tehran 19556, Iran; The Republican Research and Practical Centre for Epidemiology and Microbiology, Filimonova 23, Minsk, Belarus.
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Ponnusamy D, Clinkenbeard KD. Yersinia pestis intracellular parasitism of macrophages from hosts exhibiting high and low severity of plague. PLoS One 2012; 7:e42211. [PMID: 22848745 PMCID: PMC3407133 DOI: 10.1371/journal.pone.0042211] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 07/03/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Yersinia pestis causes severe disease in natural rodent hosts, but mild to inapparent disease in certain rodent predators such as dogs. Y. pestis initiates infection in susceptible hosts by parasitizing and multiplying intracellularly in local macrophages prior to systemic dissemination. Thus, we hypothesize that Y. pestis disease severity may depend on the degree to which intracellular Y. pestis overcomes the initial host macrophage imposed stress. METHODOLOGY/PRINCIPAL FINDINGS To test this hypothesis, the progression of in vitro infection by Y. pestis KIM62053.1+ of mouse splenic and RAW264.7 tissue culture macrophages and dog peripheral blood-derived and DH82 tissue culture macrophages was studied using microscopy and various parameters of infection. The study showed that during the early stage of infection, intracellular Y. pestis assumed filamentous cellular morphology with multiple copies of the genome per bacterium in both mouse and dog macrophages. Later, in mouse macrophages, the infection elicited spacious vacuolar extension of Yersinia containing vacuoles (YCV), and the filamentous Y. pestis reverted to coccobacillary morphology with genomic equivalents approximately equaling colony forming units. In contrast, Y. pestis infected dog macrophages did not show noticeable extension of YCV, and intracellular Y. pestis retained the filamentous cellular morphology for the entire experiment in DH82 cells or were killed by blood-derived macrophages. In addition, during the later stage of infection, Y. pestis infected mouse macrophages exhibited cell lysis whereas dog macrophages did not. CONCLUSION/SIGNIFICANCE Overall, these results support our hypothesis that Y. pestis in mouse macrophages can overcome the initial intracellular stress necessary for subsequent systemic infection. However, in dogs, failure of Y. pestis to overcome macrophage imposed stress may result in mild or in apparent disease in dogs.
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Affiliation(s)
- Duraisamy Ponnusamy
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Kenneth D. Clinkenbeard
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
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Mycobacterium tuberculosis protein kinase K enables growth adaptation through translation control. J Bacteriol 2012; 194:4184-96. [PMID: 22661693 DOI: 10.1128/jb.00585-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis serine/threonine protein kinases (STPKs) are responsible for orchestrating critical metabolic and physiological changes that dictate mycobacterial growth adaptation. Previously, we established that PknK participates in regulatory pathways that slow the growth of M. tuberculosis in a variety of in vitro stress environments and during persistent infection in mice. In the present study, we have elaborated on the mechanism of PknK-mediated regulation. Through transcription profiling of wild-type H37Rv and a ΔpknK mutant strain during logarithmic and stationary growth phases, we determined that PknK regulates the expression of a large subset of tRNA genes so that regulation is synchronized with growth phase and cellular energy status. Elevated levels of wild-type M. tuberculosis PknK (PknK(Mtb)), but not phosphorylation-defective PknK(Mtb), in Mycobacterium smegmatis cause significant retardation of the growth rate and altered colony morphology. We investigated a role for PknK in translational control and established that PknK directs the inhibition of in vitro transcription and translation processes in a phosphorylation-dependent manner. Increasing concentrations of ATP or PknK exert cooperative effects and enhance the inhibitory function of PknK. Furthermore, truncation and mutational analyses of PknK revealed that PknK is autoregulated via intramolecular interactions with its C-terminal region. Significantly, the invariant lysine 55 residue was only essential for activity in the full-length PknK protein, and the truncated mutant proteins were active. A model for PknK autoregulation is proposed and discussed.
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Plocinska R, Purushotham G, Sarva K, Vadrevu IS, Pandeeti EVP, Arora N, Plocinski P, Madiraju MV, Rajagopalan M. Septal localization of the Mycobacterium tuberculosis MtrB sensor kinase promotes MtrA regulon expression. J Biol Chem 2012; 287:23887-99. [PMID: 22610443 DOI: 10.1074/jbc.m112.346544] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanisms responsible for activation of the MtrAB two-component regulatory signal transduction system, which includes sensor kinase MtrB and response regulator MtrA, are unknown. Here, we show that an MtrB-GFP fusion protein localized to the cell membrane, the septa, and the poles in Mycobacterium tuberculosis and Mycobacterium smegmatis. This localization was independent of MtrB phosphorylation status but dependent upon the assembly of FtsZ, the initiator of cell division. The M. smegmatis mtrB mutant was filamentous, defective for cell division, and contained lysozyme-sensitive cell walls. The mtrB phenotype was complemented by either production of MtrB protein competent for phosphorylation or overproduction of MtrA(Y102C) and MtrA(D13A) mutant proteins exhibiting altered phosphorylation potential, indicating that either MtrB phosphorylation or MtrB independent expression of MtrA regulon genes, including those involved in cell wall processing, are necessary for regulated cell division. In partial support of this observation, we found that the essential cell wall hydrolase ripA is an MtrA target and that the expression of bona fide MtrA targets ripA, fbpB, and dnaA were compromised in the mtrB mutant and partially rescued upon MtrA(Y102C) and MtrA(D13A) overproduction. MtrB septal assembly was compromised upon FtsZ depletion and exposure of cells to mitomycin C, a DNA damaging agent, which interferes with FtsZ ring assembly. Expression of MtrA targets was also compromised under the above conditions, indicating that MtrB septal localization and MtrA regulon expression are linked. We propose that MtrB septal association is a necessary feature of MtrB activation that promotes MtrA phosphorylation and MtrA regulon expression.
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Affiliation(s)
- Renata Plocinska
- Biomedical Research, The University of Texas Health Science Center, Tyler, Texas 75708-3154, USA
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