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Multifork chromosome replication in slow-growing bacteria. Sci Rep 2017; 7:43836. [PMID: 28262767 PMCID: PMC5338351 DOI: 10.1038/srep43836] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 01/30/2017] [Indexed: 01/20/2023] Open
Abstract
The growth rates of bacteria must be coordinated with major cell cycle events, including chromosome replication. When the doubling time (Td) is shorter than the duration of chromosome replication (C period), a new round of replication begins before the previous round terminates. Thus, newborn cells inherit partially duplicated chromosomes. This phenomenon, which is termed multifork replication, occurs among fast-growing bacteria such as Escherichia coli and Bacillus subtilis. In contrast, it was historically believed that slow-growing bacteria (including mycobacteria) do not reinitiate chromosome replication until the previous round has been completed. Here, we use single-cell time-lapse analyses to reveal that mycobacterial cell populations exhibit heterogeneity in their DNA replication dynamics. In addition to cells with non-overlapping replication rounds, we observed cells in which the next replication round was initiated before completion of the previous replication round. We speculate that this heterogeneity may reflect a relaxation of cell cycle checkpoints, possibly increasing the ability of slow-growing mycobacteria to adapt to environmental conditions.
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52
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Cserti E, Rosskopf S, Chang YW, Eisheuer S, Selter L, Shi J, Regh C, Koert U, Jensen GJ, Thanbichler M. Dynamics of the peptidoglycan biosynthetic machinery in the stalked budding bacteriumHyphomonas neptunium. Mol Microbiol 2017; 103:875-895. [DOI: 10.1111/mmi.13593] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Emöke Cserti
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
- Max Planck Institute for Terrestrial Microbiology; Marburg 35043 Germany
| | - Sabine Rosskopf
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
| | - Yi-Wei Chang
- Division of Biology and Bioengineering; California Institute of Technology; Pasadena CA 91125 USA
| | - Sabrina Eisheuer
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
- Max Planck Institute for Terrestrial Microbiology; Marburg 35043 Germany
| | - Lars Selter
- Faculty of Chemistry; Philipps-Universität; Marburg Germany
| | - Jian Shi
- Division of Biology and Bioengineering; California Institute of Technology; Pasadena CA 91125 USA
| | - Christina Regh
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
| | - Ulrich Koert
- Faculty of Chemistry; Philipps-Universität; Marburg Germany
| | - Grant J. Jensen
- Division of Biology and Bioengineering; California Institute of Technology; Pasadena CA 91125 USA
- Howard Hughes Medical Institute, California Institute of Technology; Pasadena CA 91125 USA
| | - Martin Thanbichler
- Faculty of Biology; Philipps-Universität; Marburg 35043 Germany
- Max Planck Institute for Terrestrial Microbiology; Marburg 35043 Germany
- LOEWE Center for Synthetic Microbiology; Marburg 35043 Germany
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53
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Abstract
Mycobacteria grow and divide asymmetrically, creating variability in growth pole age, growth properties, and antibiotic susceptibilities. Here, we investigate the importance of growth pole age and other growth properties in determining the spectrum of responses of Mycobacterium smegmatis to challenge with rifampicin. We used a combination of live-cell microscopy and modeling to prospectively identify subpopulations with altered rifampicin susceptibility. We found two subpopulations that had increased susceptibility. At the initiation of treatment, susceptible cells were either small and at early stages of the cell cycle, or large and in later stages of their cell cycle. In contrast to this temporal window of susceptibility, tolerance was associated with factors inherited at division: long birth length and mature growth poles. Thus, rifampicin response is complex and due to a combination of differences established from both asymmetric division and the timing of treatment relative to cell birth.
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54
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Turapov O, Loraine J, Jenkins CH, Barthe P, McFeely D, Forti F, Ghisotti D, Hesek D, Lee M, Bottrill AR, Vollmer W, Mobashery S, Cohen-Gonsaud M, Mukamolova GV. The external PASTA domain of the essential serine/threonine protein kinase PknB regulates mycobacterial growth. Open Biol 2016; 5:150025. [PMID: 26136255 PMCID: PMC4632501 DOI: 10.1098/rsob.150025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PknB is an essential serine/threonine protein kinase required for mycobacterial cell division and cell-wall biosynthesis. Here we demonstrate that overexpression of the external PknB_PASTA domain in mycobacteria results in delayed regrowth, accumulation of elongated bacteria and increased sensitivity to β-lactam antibiotics. These changes are accompanied by altered production of certain enzymes involved in cell-wall biosynthesis as revealed by proteomics studies. The growth inhibition caused by overexpression of the PknB_PASTA domain is completely abolished by enhanced concentration of magnesium ions, but not muropeptides. Finally, we show that the addition of recombinant PASTA domain could prevent regrowth of Mycobacterium tuberculosis, and therefore offers an alternative opportunity to control replication of this pathogen. These results suggest that the PknB_PASTA domain is involved in regulation of peptidoglycan biosynthesis and maintenance of cell-wall architecture.
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Affiliation(s)
- Obolbek Turapov
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Jessica Loraine
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Christopher H Jenkins
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Philippe Barthe
- Centre de Biochimie Structurale, CNRS UMR 5048, 29, rue de Navacelles, Montpellier 34090, France INSERM U1054, Université Montpellier I et II, Montpellier, France
| | - Daniel McFeely
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Francesca Forti
- Dipartimento di BioScienze, Università degli Studi di Milano, Milan, Italy
| | - Daniela Ghisotti
- Dipartimento di BioScienze, Università degli Studi di Milano, Milan, Italy
| | - Dusan Hesek
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Andrew R Bottrill
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4AX, UK
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Martin Cohen-Gonsaud
- Centre de Biochimie Structurale, CNRS UMR 5048, 29, rue de Navacelles, Montpellier 34090, France INSERM U1054, Université Montpellier I et II, Montpellier, France
| | - Galina V Mukamolova
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
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55
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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: 159] [Impact Index Per Article: 19.9] [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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56
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Abstract
A major factor complicating efforts to control the tuberculosis epidemic is the long duration of treatment required to successfully clear the infection. One reason that long courses of treatment are required may be the fact that mycobacterial cells arise during the course of infection that are less susceptible to antibiotics. Here we describe the paradigms of phenotypic drug tolerance and resistance as they apply to mycobacteria. We then discuss the mechanisms by which phenotypically drug-tolerant and -resistant cells arise both at a population level and in specialized subpopulations of cells that may be especially important in allowing the bacterium to survive in the face of treatment. These include general mechanisms that have been shown to alter the susceptibility of mycobacteria to antibiotics including growth arrest, efflux pump induction, and biofilm formation. In addition, we discuss emerging data from single-cell studies of mycobacteria that have identified unique ways in which specialized subpopulations of cells arise that vary in their frequency, in their susceptibility to drug, and in their stability over time.
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57
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Uhía I, Williams KJ, Shahrezaei V, Robertson BD. Mycobacterial Growth. Cold Spring Harb Perspect Med 2015; 5:cshperspect.a021097. [PMID: 25957314 DOI: 10.1101/cshperspect.a021097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this work, we review progress made in understanding the molecular underpinnings of growth and division in mycobacteria, concentrating on work published since the last comprehensive review ( Hett and Rubin 2008). We have focused on exciting work making use of new time-lapse imaging technologies coupled with reporter-gene fusions and antimicrobial treatment to generate insights into how mycobacteria grow and divide in a heterogeneous manner. We try to reconcile the different observations reported, providing a model of how they might fit together. We also review the topic of mycobacterial spores, which has generated considerable discussion during the last few years. Resuscitation promoting factors, and regulation of growth and division, have also been actively researched, and we summarize progress in these areas.
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Affiliation(s)
- Iria Uhía
- Department of Medicine, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Kerstin J Williams
- Department of Medicine, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Vahid Shahrezaei
- Department of Mathematics, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Brian D Robertson
- Department of Medicine, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, United Kingdom
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58
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Dusny C, Grünberger A, Probst C, Wiechert W, Kohlheyer D, Schmid A. Technical bias of microcultivation environments on single-cell physiology. LAB ON A CHIP 2015; 15:1822-1834. [PMID: 25710324 DOI: 10.1039/c4lc01270d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Microscale cultivation systems are important tools to elucidate cellular dynamics beyond the population average and understand the functional architecture of single cells. However, there is scant knowledge about the bias of different microcultivation technologies on cellular functions. We therefore performed a systematic cross-platform comparison of three different microscale cultivation systems commonly harnessed in single-cell analysis: microfluidic non-contact cell traps driven by negative dielectrophoresis, microfluidic monolayer growth chambers, and semi-solid agarose pads. We assessed the specific single-cell growth rates, division rates and morphological characteristics of single Corynebacterium glutamicum cells and microcolonies as a bacterial model organism with medical and biotechnological relevance under standardized growth conditions. Strikingly, the specific single-cell and microcolony growth rates, μmax, were robust and conserved for several cell generations with all three microcultivation technologies, whereas the division rates of cells grown on agarose pads deviated by up to 50% from those of cells cultivated in negative dielectrophoresis traps and monolayer growth chambers. Furthermore, morphological characteristics like cell lengths and division symmetries of individual cells were affected when the cells were grown on agarose pads. This indicated a significant impact of solid cultivation supports on cellular traits. The results demonstrate the impact of microcultivation technology on microbial physiology for the first time and show the need for a careful selection and design of the microcultivation technology in order to allow unbiased analysis of cellular behavior.
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Affiliation(s)
- Christian Dusny
- Laboratory of Chemical Biotechnology, Department of Biochemical & Chemical Engineering, TU Dortmund University, Emil-Figge-Str. 66, 44227 Dortmund, Germany.
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59
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Abstract
It has recently been demonstrated that bacterial chromosomes are highly organized, with specific positioning of the replication initiation region. Moreover, the positioning of the replication machinery (replisome) has been shown to be variable and dependent on species-specific cell cycle features. Here, we analyzed replisome positions in Mycobacterium smegmatis, a slow-growing bacterium that exhibits characteristic asymmetric polar cell extension. Time-lapse fluorescence microscopy analyses revealed that the replisome is slightly off-center in mycobacterial cells, a feature that is likely correlated with the asymmetric growth of Mycobacterium cell poles. Estimates of the timing of chromosome replication in relation to the cell cycle, as well as cell division and chromosome segregation events, revealed that chromosomal origin-of-replication (oriC) regions segregate soon after the start of replication. Moreover, our data demonstrate that organization of the chromosome by ParB determines the replisome choreography. Despite significant progress in elucidating the basic processes of bacterial chromosome replication and segregation, understanding of chromosome dynamics during the mycobacterial cell cycle remains incomplete. Here, we provide in vivo experimental evidence that replisomes in Mycobacterium smegmatis are highly dynamic, frequently splitting into two distinct replication forks. However, unlike in Escherichia coli, the forks do not segregate toward opposite cell poles but remain in relatively close proximity. In addition, we show that replication cycles do not overlap. Finally, our data suggest that ParB participates in the positioning of newly born replisomes in M. smegmatis cells. The present results broaden our understanding of chromosome segregation in slow-growing bacteria. In view of the complexity of the mycobacterial cell cycle, especially for pathogenic representatives of the genus, understanding the mechanisms and factors that affect chromosome dynamics will facilitate the identification of novel antimicrobial factors.
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60
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The essential features and modes of bacterial polar growth. Trends Microbiol 2015; 23:347-53. [PMID: 25662291 DOI: 10.1016/j.tim.2015.01.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/19/2014] [Accepted: 01/07/2015] [Indexed: 01/25/2023]
Abstract
Polar growth represents a surprising departure from the canonical dispersed cell growth model. However, we know relatively little of the underlying mechanisms governing polar growth or the requisite suite of factors that direct polar growth. Underscoring how classic doctrine can be turned on its head, the peptidoglycan layer of polar-growing bacteria features unusual crosslinks and in some species the quintessential cell division proteins FtsA and FtsZ are recruited to the growing poles. Remarkably, numerous medically important pathogens utilize polar growth, accentuating the need for intensive research in this area. Here we review models of polar growth in bacteria based on recent research in the Actinomycetales and Rhizobiales, with emphasis on Mycobacterium and Agrobacterium species.
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61
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Siegrist MS, Swarts BM, Fox DM, Lim SA, Bertozzi CR. Illumination of growth, division and secretion by metabolic labeling of the bacterial cell surface. FEMS Microbiol Rev 2015; 39:184-202. [PMID: 25725012 DOI: 10.1093/femsre/fuu012] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The cell surface is the essential interface between a bacterium and its surroundings. Composed primarily of molecules that are not directly genetically encoded, this highly dynamic structure accommodates the basic cellular processes of growth and division as well as the transport of molecules between the cytoplasm and the extracellular milieu. In this review, we describe aspects of bacterial growth, division and secretion that have recently been uncovered by metabolic labeling of the cell envelope. Metabolite derivatives can be used to label a variety of macromolecules, from proteins to non-genetically-encoded glycans and lipids. The embedded metabolite enables precise tracking in time and space, and the versatility of newer chemoselective detection methods offers the ability to execute multiple experiments concurrently. In addition to reviewing the discoveries enabled by metabolic labeling of the bacterial cell envelope, we also discuss the potential of these techniques for translational applications. Finally, we offer some guidelines for implementing this emerging technology.
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Affiliation(s)
- M Sloan Siegrist
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Benjamin M Swarts
- Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859, USA
| | - Douglas M Fox
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Shion An Lim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Carolyn R Bertozzi
- Department of Chemistry, University of California, Berkeley, CA 94720, USA Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
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62
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Dhar N, Manina G. Single-cell analysis of mycobacteria using microfluidics and time-lapse microscopy. Methods Mol Biol 2015; 1285:241-256. [PMID: 25779320 DOI: 10.1007/978-1-4939-2450-9_14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The crucial role of phenotypic heterogeneity in bacterial physiology and adaptive responses has required the introduction of new ways to investigate bacterial individuality. Time-lapse microscopy is a powerful technique for evaluating phenotypic diversity in bacteria at the single-cell level, whether exploring the dynamics of gene expression and protein localization or characterizing the heterogeneous phenotypic response to perturbations. Here, we present protocols to carry out time-lapse imaging of mycobacteria at the single-cell level using either agarose pads or customized microfluidic devices. The sequences of images obtained can be analyzed using programs such as ImageJ and allow the investigator not only to extract various parameters of growth and gene expression dynamics but also to unravel the physiological basis behind phenomenon such as persistence against stresses.
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Affiliation(s)
- Neeraj Dhar
- Laboratory of Microbiology and Microsystems, School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Station 19, Office SV 3832, Lausanne, CH-1015, Switzerland,
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63
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Manina G, Dhar N, McKinney J. Stress and Host Immunity Amplify Mycobacterium tuberculosis Phenotypic Heterogeneity and Induce Nongrowing Metabolically Active Forms. Cell Host Microbe 2015; 17:32-46. [DOI: 10.1016/j.chom.2014.11.016] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/19/2014] [Accepted: 11/06/2014] [Indexed: 11/28/2022]
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64
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Bouklas T, Fries BC. Aging as an emergent factor that contributes to phenotypic variation in Cryptococcus neoformans. Fungal Genet Biol 2014; 78:59-64. [PMID: 25307541 DOI: 10.1016/j.fgb.2014.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/26/2014] [Accepted: 10/02/2014] [Indexed: 12/15/2022]
Abstract
Cryptococcus neoformans, similar to other eukaryotes, undergoes replicative aging. Replicative life spans have been determined for clinical C. neoformans strains, and although they are a reproducible trait, life spans vary considerably among strains. C. neoformans has been proposed as an ideal model organism to investigate the contribution of replicative aging in a fungal pathogen population to emerging phenotypic variation during chronic cryptococcal infections. C. neoformans cells of advanced generational age manifest a distinct phenotype; specifically, a larger cell size, a thicker cell wall, drug resistance, as well as resistance to hydrogen peroxide-mediated killing. Consequently, old cells are selected in the host environment during chronic infection and aging could be an unanticipated mechanism of pathogen adaptation that contributes to persistent disease. Aging as a natural process of phenotypic variation should be further studied as it likely is also relevant for other eukaryotic pathogen populations that undergo asymmetric replicative aging.
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Affiliation(s)
- Tejas Bouklas
- Department of Medicine (Division of Infectious Diseases), Stony Brook University, Stony Brook, NY, USA
| | - Bettina C Fries
- Department of Medicine (Division of Infectious Diseases), Stony Brook University, Stony Brook, NY, USA; Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA.
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65
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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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66
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Abstract
Mycobacterium tuberculosis, which is the aetiological agent of tuberculosis, owes much of its success as a pathogen to its unique cell wall and unusual mechanism of growth, which facilitate its adaptation to the human host and could have a role in clinical latency. Asymmetric growth and division increase population heterogeneity, which may promote antibiotic tolerance and the fitness of single cells. In this Review, we describe the unusual mechanisms of mycobacterial growth, cell wall biogenesis and division, and discuss how these processes might affect the survival of M. tuberculosis in vivo and contribute to the persistence of infection.
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67
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Vijay S, Mukkayyan N, Ajitkumar P. Highly Deviated Asymmetric Division in Very Low Proportion of Mycobacterial Mid-log Phase Cells. Open Microbiol J 2014; 8:40-50. [PMID: 24949109 PMCID: PMC4062944 DOI: 10.2174/1874285801408010040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 03/08/2014] [Accepted: 04/07/2014] [Indexed: 11/23/2022] Open
Abstract
In this study, we show that about 20% of the septating Mycobacterium smegmatis and Mycobacterium xenopi cells in the exponential phase populationdivideasymmetrically, with an unusually high deviation (17 ± 4%) in the division site from the median, to generate short cells and long cells, thereby generating population heterogeneity. This mode of division is very different from the symmetric division of themajority (about 80%) of the septating cells in the Mycobacterium smegmatis, Mycobacterium marinum, and Mycobacterium bovis BCG exponential phase population, with 5-10% deviation in the division site from the mid-cell site, as reported by recent studies. The short cells and the long cells further grew and divided to generate a population. We speculate that the generation of the short cells and the long cells through the highly deviated asymmetric divisionin the low proportions of mycobacterial population may have a role in stress tolerance.
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Affiliation(s)
- Srinivasan Vijay
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012,Karnataka,India
| | - Nagaraja Mukkayyan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012,Karnataka,India
| | - Parthasarathi Ajitkumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore - 560012,Karnataka,India
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68
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Sochorová Z, Petráčková D, Sitařová B, Buriánková K, Bezoušková S, Benada O, Kofroňová O, Janeček J, Halada P, Weiser J. Morphological and proteomic analysis of early stage air-liquid interface biofilm formation in Mycobacterium smegmatis. MICROBIOLOGY-SGM 2014; 160:1346-1356. [PMID: 24760966 DOI: 10.1099/mic.0.076174-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We studied the early stages of pellicle formation by Mycobacterium smegmatis on the surface of a liquid medium [air-liquid interface (A-L)]. Using optical and scanning electron microscopy, we showed the formation of a compact biofilm pellicle from micro-colonies over a period of 8-30 h. The cells in the pellicle changed size and cell division pattern during this period. Based on our findings, we created a model of M. smegmatis A-L early pellicle formation showing the coordinate growth of cells in the micro-colonies and in the homogeneous film between them, where the accessibility to oxygen and nutrients is different. A proteomic approach utilizing high-resolution two-dimensional gel electrophoresis, in combination with mass spectrometry-based protein identification, was used to analyse the protein expression profiles of the different morphological stages of the pellicle. The proteins identified formed four expression groups; the most interesting of these groups contained the proteins with highest expression in the biofilm development phase, when the floating micro-colonies containing long and more robust cells associate into flocs and start to form a compact pellicle. The majority of these proteins, including GroEL1, are involved in cell wall synthesis or modification, mostly through the involvement of mycolic acid biosynthesis, and their expression maxima correlated with the changes in cell size and the rigidity of the bacterial cell wall observed by scanning electron microscopy.
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Affiliation(s)
- Zuzana Sochorová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Denisa Petráčková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Barbora Sitařová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Karolína Buriánková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Silvia Bezoušková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Oldřich Benada
- Department of Biology, Faculty of Science, J. E. Purkinje University in Ustí nad Labem, Ústí nad Labem, Czech Republic.,Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Olga Kofroňová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jiří Janeček
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Petr Halada
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jaroslav Weiser
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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69
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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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70
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Asymmetric cell division in Mycobacterium tuberculosis and its unique features. Arch Microbiol 2014; 196:157-68. [DOI: 10.1007/s00203-014-0953-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 11/06/2013] [Accepted: 01/18/2014] [Indexed: 10/25/2022]
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71
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Kester JC, Fortune SM. Persisters and beyond: mechanisms of phenotypic drug resistance and drug tolerance in bacteria. Crit Rev Biochem Mol Biol 2013; 49:91-101. [PMID: 24328927 DOI: 10.3109/10409238.2013.869543] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
One of the challenges in clinical infectious diseases is the problem of chronic infections, which can require long durations of antibiotic treatment and often recur. An emerging explanation for the refractoriness of some infections to treatment is the existence of subpopulations of drug tolerant cells. While typically discussed as "persister" cells, it is becoming increasingly clear that there is significant heterogeneity in drug responses within a bacterial population and that multiple mechanisms underlie the emergence of drug tolerant and drug-resistant subpopulations. Many of these parallel mechanisms have been shown to affect drug susceptibility at the level of a whole population. Here we review mechanisms of phenotypic drug tolerance and resistance in bacteria with the goal of providing a framework for understanding the similarities and differences in these cells.
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Affiliation(s)
- Jemila C Kester
- Department of Immunology and Infectious Diseases, Harvard School of Public Health , Boston, MA , USA
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72
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den Blaauwen T. Prokaryotic cell division: flexible and diverse. Curr Opin Microbiol 2013; 16:738-44. [PMID: 24084468 DOI: 10.1016/j.mib.2013.09.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/20/2013] [Accepted: 09/06/2013] [Indexed: 01/06/2023]
Abstract
Gram-negative rod-shaped bacteria have different approaches to position the cell division initiating Z-ring at the correct moment in their cell division cycle. The subsequent maturation into a functional division machine occurs in vastly different species in two steps with appreciable time in between these. The function of this time delay is unclear, but may partly be explained by competition for Lipid-II between proteins involved in length growth that interact directly with the Z-ring early in the maturation phase and the proteins involved in septum synthesis. A second possible activity of the early Z-ring might be the monitoring of or the active involvement in DNA segregation through proteins such as ZapA and ZapB/MatP and their homologues.
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Affiliation(s)
- Tanneke den Blaauwen
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
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73
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Santi I, Dhar N, Bousbaine D, Wakamoto Y, McKinney JD. Single-cell dynamics of the chromosome replication and cell division cycles in mycobacteria. Nat Commun 2013; 4:2470. [DOI: 10.1038/ncomms3470] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/20/2013] [Indexed: 11/09/2022] Open
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74
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Kysela DT, Brown PJB, Huang KC, Brun YV. Biological consequences and advantages of asymmetric bacterial growth. Annu Rev Microbiol 2013; 67:417-35. [PMID: 23808335 DOI: 10.1146/annurev-micro-092412-155622] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Asymmetries in cell growth and division occur in eukaryotes and prokaryotes alike. Even seemingly simple and morphologically symmetric cell division processes belie inherent underlying asymmetries in the composition of the resulting daughter cells. We consider the types of asymmetry that arise in various bacterial cell growth and division processes, which include both conditionally activated mechanisms and constitutive, hardwired aspects of bacterial life histories. Although asymmetry disposes some cells to the deleterious effects of aging, it may also benefit populations by efficiently purging accumulated damage and rejuvenating newborn cells. Asymmetries may also generate phenotypic variation required for successful exploitation of variable environments, even when extrinsic changes outpace the capacity of cells to sense and respond to challenges. We propose specific experimental approaches to further develop our understanding of the prevalence and the ultimate importance of asymmetric bacterial growth.
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Affiliation(s)
- David T Kysela
- Department of Biology, Indiana University, Bloomington, Indiana 47405;
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75
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Singh B, Nitharwal RG, Ramesh M, Pettersson BMF, Kirsebom LA, Dasgupta S. Asymmetric growth and division inMycobacteriumspp.: compensatory mechanisms for non-medial septa. Mol Microbiol 2013; 88:64-76. [DOI: 10.1111/mmi.12169] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Bhupender Singh
- Department of Cell and Molecular Biology; Uppsala University Biomedical Center; Box 596; 751 24; Uppsala; Sweden
| | - Ram Gopal Nitharwal
- Department of Cell and Molecular Biology; Uppsala University Biomedical Center; Box 596; 751 24; Uppsala; Sweden
| | - Malavika Ramesh
- Department of Cell and Molecular Biology; Uppsala University Biomedical Center; Box 596; 751 24; Uppsala; Sweden
| | - B. M. Fredrik Pettersson
- Department of Cell and Molecular Biology; Uppsala University Biomedical Center; Box 596; 751 24; Uppsala; Sweden
| | - Leif A. Kirsebom
- Department of Cell and Molecular Biology; Uppsala University Biomedical Center; Box 596; 751 24; Uppsala; Sweden
| | - Santanu Dasgupta
- Department of Cell and Molecular Biology; Uppsala University Biomedical Center; Box 596; 751 24; Uppsala; Sweden
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