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Peng Y, Han X, Xu P, Tao F. Next‐Generation Microbial Workhorses: Comparative Genomic Analysis of Fast‐GrowingVibrioStrains Reveals Their Biotechnological Potential. Biotechnol J 2020; 15:e1900499. [DOI: 10.1002/biot.201900499] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/06/2020] [Indexed: 01/07/2023]
Affiliation(s)
- Yuan Peng
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences and School of Life Sciences and BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Xiao Han
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences and School of Life Sciences and BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Ping Xu
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences and School of Life Sciences and BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Fei Tao
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental Sciences and School of Life Sciences and BiotechnologyShanghai Jiao Tong University Shanghai 200240 P. R. China
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Involvement of organic acids and amino acids in ameliorating Ni(II) toxicity induced cell cycle dysregulation in Caulobacter crescentus: a metabolomics analysis. Appl Microbiol Biotechnol 2018; 102:4563-4575. [PMID: 29616314 DOI: 10.1007/s00253-018-8938-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
Nickel (Ni(II)) toxicity is addressed by many different bacteria, but bacterial responses to nickel stress are still unclear. Therefore, we studied the effect of Ni(II) toxicity on cell proliferation of α-proteobacterium Caulobacter crescentus. Next, we showed the mechanism that allows C. crescentus to survive in Ni(II) stress condition. Our results revealed that the growth of C. crescentus is severely affected when the bacterium was exposed to different Ni(II) concentrations, 0.003 mM slightly affected the growth, 0.008 mM reduced the growth by 50%, and growth was completely inhibited at 0.015 mM. It was further shown that Ni(II) toxicity induced mislocalization of major regulatory proteins such as MipZ, FtsZ, ParB, and MreB, resulting in dysregulation of the cell cycle. GC-MS metabolomics analysis of Ni(II) stressed C. crescentus showed an increased level of nine important metabolites including TCA cycle intermediates and amino acids. This indicates that changes in central carbon metabolism and nitrogen metabolism are linked with the disruption of cell division process. Addition of malic acid, citric acid, alanine, proline, and glutamine to 0.015 mM Ni(II)-treated C. crescentus restored its growth. Thus, the present work shows a protective effect of these organic acids and amino acids on Ni(II) toxicity. Metabolic stimulation through the PutA/GlnA pathway, accelerated degradation of CtrA, and Ni-chelation by organic acids or amino acids are some of the possible mechanisms suggested to be involved in enhancing C. crescentus's tolerance. Our results shed light on the mechanism of increased Ni(II) tolerance in C. crescentus which may be useful in bioremediation strategies and synthetic biology applications such as the development of whole cell biosensor.
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Battogtokh D, Aihara K, Tyson JJ. Synchronization of eukaryotic cells by periodic forcing. PHYSICAL REVIEW LETTERS 2006; 96:148102. [PMID: 16712125 DOI: 10.1103/physrevlett.96.148102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Indexed: 05/09/2023]
Abstract
We study a cell population described by a minimal mathematical model of the eukaryotic cell cycle subject to periodic forcing that simultaneously perturbs the dynamics of the cell cycle engine and cell growth, and we show that the population can be synchronized in a mode-locked regime. By simplifying the model to two variables, for the phase of cell cycle progression and the mass of the cell, we calculate the Lyapunov exponents to obtain the parameter window for synchronization. We also discuss the effects of intrinsic mitotic fluctuations, asymmetric division, and weak mutual coupling on the pace of synchronization.
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Affiliation(s)
- Dorjsuren Battogtokh
- Department of Biology, Virginia Polytechnic Institute and State University Blacksburg, VA 24061-0106, USA.
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Schreiber G, Ron EZ, Glaser G. ppGpp-mediated regulation of DNA replication and cell division in Escherichia coli. Curr Microbiol 1995; 30:27-32. [PMID: 7765879 DOI: 10.1007/bf00294520] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
ppGpp serves as an alarmon in prokaryotes, distributing and coordinating different cellular processes according to the nutritional potential of the growth medium. This work is interpreted as favoring the view that, in addition to its previously documented role in regulating the rate of ribosome synthesis, ppGpp participates in coordinating DNA replication and cell division. We studied the effects of ppGpp on the cell division cycle, using cells containing plasmid pSM11 that codes for the 55-kDa truncated RelA protein under the inducible Ptac promoter. In this system it was found that the rate of initiation of new rounds of DNA replication is inversely correlated with the intracellular level of ppGpp. Furthermore, ppGpp levels similar to those found during the activation of stringent control inhibited replication initiation, in a manner comparable to that resulting from inhibition of protein synthesis by amino acid starvation or by chloramphenicol addition. However, in contrast to chloramphenicol treatment, elevated ppGpp levels did not block septum formation, and, in fact, there is some evidence for enhanced septation. As a result, the residual cell division following elevation in ppGpp levels was higher than after chloramphenicol treatment, resulting in cells with a size similar to that of stationary phase cells.
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Affiliation(s)
- G Schreiber
- Department of Cellular Biochemistry, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Grossman N, Rosner E, Ron EZ. Termination of DNA replication is required for cell division in Escherichia coli. J Bacteriol 1989; 171:74-9. [PMID: 2644214 PMCID: PMC209556 DOI: 10.1128/jb.171.1.74-79.1989] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The correlation between termination of DNA replication and cell division in Escherichia coli was studied under conditions in which DNA replication was slowed down without inducing SOS functions. The experimental system used involved amino acid starvation of synchronized cells in the presence of methionine. The results further support the essential correlation between termination of DNA replication and initiation of division processes.
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Affiliation(s)
- N Grossman
- Department of Microbiology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel
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Abstract
The experiments described in this report were designed to find out whether there is a minimal size threshold for cell division or for DNA replication in Escherichia coli. Cells with decreasing size (or mass) were obtained by successive amino acid starvations. Following two starvations, the cells were at least 30% smaller than unstarved newborn cells. The results suggest that this size is below a minimal size threshold for cell division but not for initiation of DNA replication.
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Affiliation(s)
- N Grossman
- Department of Microbiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
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Pierucci O, Rickert M. Duplication of Escherichia coli during inhibition of net phospholipid synthesis. J Bacteriol 1985; 162:374-82. [PMID: 3884597 PMCID: PMC218999 DOI: 10.1128/jb.162.1.374-382.1985] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In Escherichia coli BB26-36, the inhibition of net phospholipid synthesis during glycerol starvation affected cell duplication in a manner that was similar in some respects to that observed during the inhibition of protein synthesis. Ongoing rounds of chromosome replication continued, and cells in the D period divided. The initiation of new rounds of chromosome replication and division of cells in the C period were inhibited. Unlike the inhibition of protein synthesis, however, the accumulation of initiation potential in dnaA and dnaC mutants at the nonpermissive temperature was not affected by the inhibition of phospholipid synthesis. Furthermore, proteins synthesized during the inhibition of phospholipid synthesis can be utilized later for division. The results are consistent with a dual requirement for protein and phospholipid synthesis for both the inauguration of new rounds of chromosome replication and the initiation of septum formation. Once initiated, both processes progress to completion independent of continuous phospholipid and protein synthesis.
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Grossman N, Ron EZ, Woldringh CL. Changes in cell dimensions during amino acid starvation of Escherichia coli. J Bacteriol 1982; 152:35-41. [PMID: 6749809 PMCID: PMC221371 DOI: 10.1128/jb.152.1.35-41.1982] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Electron microscopic analysis was used to study cells of Escherichia coli B and K-12 during and after amino acid starvation. The results confirmed our previous conclusion that cell division and initiation of DNA replication occur at a smaller cell volume after amino acid starvation. Although during short starvation periods, the number of constricting cells decreased due to residual division, it appears that during prolonged starvation, cells of E. coli B and K-12 were capable of initiating new constrictions. During amino acid starvation, cell diameter decreased significantly. The decrease was reversed only after two generation times after the resumption of protein synthesis and was larger in magnitude than that previously observed before division (F. J. Trueba and C. L. Woldringh, J. Bacteriol. 142:869-878, 1980). This decrease in cell diameter correlates with synchronization of cell division which has been shown to occur after amino acid starvation.
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Abstract
Most bacteria have evolved a number of regulatory mechanisms which allow them to maintain a balanced and rather constant cellular composition in response to nutritional variations. In particular, when the availability of any aminoacyl-tRNA species becomes limiting (namely through amino acid starvation or inactivation of an aminoacyl-tRNA synthetase), several biochemically distinct physiological processes are significantly modified. This coordinate adjustment of cellular activity is termed the "stringent response". Under such conditions of aminoacyl-tRNA limitation, protein synthesis still proceeds, but various quantitative as well as qualitative changes in polypeptide metabolism can be observed. In this review, after a brief recall of the main characteristics of the stringent response, several aspects concerning protein synthesis in deprived bacteria have been presented. First, the rates of residual protein formation, peptide chain growth and protein degradation, and the molecular weight distribution of proteins newly synthesized have been analyzed. Then, the data relative to the biosynthetic regulation of non-ribosomal and ribosomal proteins have been summarized and compared to the results obtained from in vitro experiments using transcription-translation coupled systems. Finally, the problem of translational fidelity during deprivation has been discussed in connection with the metabolic behavior of polysomal structures which are still maintained in cells. The stringent dependence of cellular activity on aminoacyl-tRNA supply is known to be abolished by single-site mutations which confer to bacteria a phenotype referred to as "relaxed". These mutant strains provide an useful analytical tool in the scope of understanding the stringency phenomenon. Therefore, their proteosynthetic activity under aminoacyl-tRNA deprivation has also been studied here, in comparison to that of normal wild-type strains.
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Dwek RD, Kobrin LH, Grossman N, Ron EZ. Synchronization of cell division in microorganisms by percoll gradients. J Bacteriol 1980; 144:17-21. [PMID: 6252189 PMCID: PMC294577 DOI: 10.1128/jb.144.1.17-21.1980] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We describe a method for obtaining synchronously dividing cells of bacteria (Escherichia coli B and K-12 and Bacillus subtilis 168) and fission yeasts (Schizosaccharomyces pombe) by the use of Percoll density gradients.
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Grossman N, Ron EZ. Initiation of deoxyribonucleic acid replication in Escherichia coli B: uncoupling from mass/deoxyribonucleic acid ratio. J Bacteriol 1980; 143:100-4. [PMID: 6995423 PMCID: PMC294188 DOI: 10.1128/jb.143.1.100-104.1980] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In Escherichia coli growing at different rates, the ratio of cell mass to the number of chromosome origins tended to be constant at the time of the initiation of deoxyribonucleic acid (DNA) replication. This observation led to the assumption that the initiation event is controlled in some way by cell mass, e.g., by a growth-dependent synthesis of an initiator or dilution of a repressor. We have now found that the initiation of DNA synthesis can be uncoupled from cell mass. We used a synchronous culture of newly divided cells of E. coli B which was obtained by the membrane elution technique (C.E. Helmstetter, J. Mol. Biol. 24: 417-427, 1967) and was starved for an amino acid. Upon restoration of the amino acid, the cells not only divided at a size that was smaller than normal, but also initiated DNA replication long before they could increase their masses to reach the expected ratio of mass/DNA presumably required for initiation.
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Tang MS, Helmstetter CE. Coordination between chromosome replication and cell division in Escherichia coli. J Bacteriol 1980; 141:1148-56. [PMID: 6988405 PMCID: PMC293799 DOI: 10.1128/jb.141.3.1148-1156.1980] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cell division properties of Escherichia coli B/r containing either a dnaC or a dnaI mutation were examined. Incubation at nonpermissive temperature resulted in the eventual production of cells of approximately normal size, or slightly smaller, which lacked chromosomal DNA. The cell division patterns in cultures which were grown at permissive temperature and then shifted to nonpermissive temperature were consistent with: first, division and equipartition of chromosomes by cells which were in the C and D periods at the time of the shift; second, an apparent delay in cell division; and third, commencement of the formation of chromosomeless cells. In glucose-grown cultures of the dnaI mutant, production of chromosomeless cells continued for at least 120 min, whereas in the dnaC mutant chromosomeless cells were formed during a single interval between 110 and 130 min after the temperature shift. The results are discussed in light of the hypothesis that replication of a specific chromosomal region is not an obligatory requirement for the initiation and completion of the processes leading to division in a cell which contains at least one functioning chromosome.
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Miyakawa Y, Komano T, Maruyama Y. Cell-cycle-specific inhibition by chloramphenicol of septum fromation and cell division in synchronized cells of Bacillus subtilis. J Bacteriol 1980; 141:502-7. [PMID: 6767682 PMCID: PMC293653 DOI: 10.1128/jb.141.2.502-507.1980] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The relationship between protein synthesis and processes of cell division was studied by using synchronized cells of Bacillus subtilis 168. The addition of chloramphenicol at the beginning of synchronous growth prevented septum formation and cell division, suggesting the requirement of protein synthesis for the processes of cell division. Experiments in which the drug was added to the cells at different cell ages showed that the protein synthesis required for the initiation of septum formation was completed at about 15 min and that the protein synthesis required for cell division was completed at about 45 min. By interpreting the result from the concept of the transition point for protein synthesis, it was suggested that the processes of cell division in B. subtilis require at least two kinds of protein molecules which are synthesized at distinct stages in the cell cycle. This was supported by the result of an experiment in which starvation and the readdition of a required amino acid to exponentially growing cells induced two steps of synchronous cell division. Further, the two transition points are in agreement with the estimations obtained by residual division after the inhibition of protein synthesis in asynchronous cells. The relationship of the timing between the completion of chromosome replication and the two transition points was also studied.
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Thomas KC, Dawson PS, Gamborg BL. Differential growth rates of Candida utilis mother and daughter cells under phased cultivation. J Bacteriol 1980; 141:1-9. [PMID: 7188766 PMCID: PMC293518 DOI: 10.1128/jb.141.1.1-9.1980] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The yeast Candida utilis was continuously synchronized by the phased method of cultivation with the nitrogen source as the growth-limiting nutrient. The doubling time (phasing period) of cells was 6 h. Both cell number and deoxyribonucleic acid synthesis showed a characteristic stepwise increase during the phased growth. The time of bud emergence coincided with the time of initiation of deoxyribonucleic acid synthesis. Size distribution studies combined with microscopic analysis showed that the cells expanded only during the unbudded phase of growth. Usually the cells stopped increasing in size about 30 min before bud emergence, and the arrest of the increase in cell volume coincided with the exhaustion of nitron from the medium. There was no net change in the volume of cells during the bud expansion phase of growth, suggesting that as the bud expanded, the volume of the mother portion of the cell decreased. After division the cells expanded slightly. The postdivision expansion of cells, unlike the growth before bud initiation, occurred in the absence of the growth-limiting nutrient. The newly formed daughter cells were smaller than the mother cells and expanded at a faster rate, so that both types of cells reached maximum size at the same time. Possible reasons for the different rates of expansion of mother and daughter cells are discussed.
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