scholarly journals RNase E Maintenance of Proper FtsZ/FtsA Ratio Required for Nonfilamentous Growth of Escherichia coli Cells but Not for Colony-Forming Ability

2006 ◽  
Vol 188 (14) ◽  
pp. 5145-5152 ◽  
Author(s):  
Masaru Tamura ◽  
Kangseok Lee ◽  
Christine A. Miller ◽  
Christopher J. Moore ◽  
Yukio Shirako ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Liquid Culture ◽  
Bacterial Cells ◽  
Rnase E ◽  
Null Mutant ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Solid Media ◽  
Rnase G

ABSTRACT Inactivation or deletion of the RNase E-encoding rne gene of Escherichia coli results in the growth of bacterial cells as filamentous chains in liquid culture (K. Goldblum and D. Apirion, J. Bacteriol. 146:128-132, 1981) and the loss of colony-forming ability (CFA) on solid media. RNase E dysfunction is also associated with abnormal processing of ftsQAZ transcripts (K. Cam, G. Rome, H. M. Krisch, and J.-P. Bouché, Nucleic Acids Res. 24:3065-3070, 1996), which encode proteins having a central role in septum formation during cell division. We show here that RNase E regulates the relative abundances of FtsZ and FtsA proteins and that RNase E depletion results in decreased FtsZ, increased FtsA, and consequently an altered FtsZ/FtsA ratio. However, while restoration of the level of FtsZ to normal in rne null mutant bacteria reverses the filamentation phenotype, it does not restore CFA. Conversely, overexpression of a related RNase, RNase G, in rne-deleted bacteria restores CFA, as previously reported, without affecting FtsZ abundance. Our results demonstrate that RNase E activity is required to maintain a proper cellular ratio of the FtsZ and FtsA proteins in E. coli but that FtsZ deficiency does not account for the nonviability of cells lacking RNase E.

scholarly journals Artificial modulation of cell width significantly affects the division time of Escherichia coli

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Baihui Liang ◽  
Baogang Quan ◽  
Junjie Li ◽  
Chantal Loton ◽  
Marie-Florence Bredeche ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Temporal Correlation ◽  
Cell Physiology ◽  
Bacterial Cells ◽  
Cell Width ◽  
Division Rate ◽  
Microscopy Imaging ◽  
Spatial And Temporal Scales ◽  
E Coli

Abstract Bacterial cells have characteristic spatial and temporal scales. For instance, Escherichia coli, the typical rod-shaped bacteria, always maintains a relatively constant cell width and cell division time. However, whether the external physical perturbation of cell width has an impact on cell division time remains largely unexplored. In this work, we developed two microchannel chips, namely straight channels and ‘necked’ channels, to precisely regulate the width of E. coli cells and to investigate the correlation between cell width and division time of the cells. Our results show that, in the straight channels, the wide cells divide much slower than narrow cells. In the ‘necked’ channels, the cell division is remarkably promoted compared to that in straight channels with the same width. Besides, fluorescence time-lapse microscopy imaging of FtsZ dynamics shows that the cell pre-constriction time is more sensitive to cell width perturbation than cell constriction time. Finally, we revealed a significant anticorrelation between the death rate and the division rate of cell populations with different widths. Our work provides new insights into the correlation between the geometrical property and division time of E. coli cells and sheds new light on the future study of spatial–temporal correlation in cell physiology.

Recruitment of the TolA protein to cell constriction sites in Escherichia coli via three separate mechanisms, and a critical role for FtsWI activity in recruitment of both TolA and TolQ.

2021 ◽  
Author(s):  
Cynthia A. Hale ◽  
Logan Persons ◽  
Piet A. J. de Boer
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Cell Envelope ◽  
Critical Role ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Future Studies ◽  
E Coli ◽  
Middle Domain ◽  
Fundamental Biological Process

The Tol-Pal system of Gram-negative bacteria helps maintain integrity of the cell envelope and ensures that invagination of the envelope layers during cell fission occurs in a well-coordinated manner. In E. coli , the five Tol-Pal proteins (TolQ, R, A, B and Pal) accumulate at cell constriction sites in a manner that normally requires the activity of the cell constriction initiation protein FtsN. While septal recruitment of TolR, TolB and Pal also requires the presence of TolQ and/or TolA, each of the the latter two can recognize constriction sites independently of the other system proteins. What attracts TolQ or TolA to these sites is unclear. We show that FtsN attracts both proteins in an indirect fashion, and that PBP1A, PBP1B and CpoB are dispensable for their septal recruitment. However, the β-lactam aztreonam readily interferes with septal accumulation of both TolQ and TolA, indicating that FtsN-stimulated production of septal peptidoglycan by the FtsWI synthase is critical to their recruitment. We also discovered that each of TolA's three domains can recognize division sites in a separate fashion. Notably, the middle domain (TolAII) is responsible for directing TolA to constriction sites in the absence of other Tol-Pal proteins and CpoB, while recruitment of TolAI and TolAIII requires TolQ and a combination of TolB, Pal, and CpoB, respectively. Additionally, we describe the construction and use of functional fluorescent sandwich fusions of the ZipA division protein, which should be more broadly valuable in future studies of the E. coli cell division machinery. IMPORTANCE Cell division (cytokinesis) is a fundamental biological process that is incompletely understood for any organism. Division of bacterial cells relies on a ring-like machinery called the septal ring or divisome that assembles along the circumference of the mother cell at the site where constriction will eventually occur. In the well-studied bacterium Escherichia coli , this machinery contains over thirty distinct proteins. We studied how two such proteins, TolA and TolQ, which also play a role in maintaining integrity of the outer-membrane, are recruited to the machinery. We find that TolA can be recruited by three separate mechanisms, and that both proteins rely on the activity of a well-studied cell division enzyme for their recruitment.

One-step deposition of a melanin-like polymer on individual Escherichia coli cells exhibiting a special UV resistance effect

RSC Advances ◽  
2016 ◽  
Vol 6 (82) ◽  
pp. 78378-78384 ◽  
Author(s):  
Bai Zhang ◽  
Zhou Sun ◽  
Yuting Bai ◽  
Hanqiong Zhuang ◽  
Dongtao Ge ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Uv Radiation ◽  
Cell Encapsulation ◽  
Uv Resistance ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
One Step ◽  
Fundamental Research

Melanin-like polydopamine encapsulated E. coli cells could retained cells viability, inhibited cell division and protected cells from UV radiation. These provide both fundamental research and applications of cell encapsulation for UV resistance.

scholarly journals Enhanced Production of δ-Guaiene, a Bicyclic Sesquiterpene Accumulated in Agarwood, by Coexpression of δ-Guaiene Synthase and Farnesyl Diphosphate Synthase Genes in Escherichia coli

2016 ◽  
Vol 11 (9) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Takahiro Kato ◽  
Jung-Bum Lee ◽  
Futoshi Taura ◽  
Fumiya Kurosaki
Keyword(s):  
Escherichia Coli ◽  
Recombinant Protein ◽  
Immunoblot Analysis ◽  
Farnesyl Diphosphate ◽  
Farnesyl Diphosphate Synthase ◽  
Transformed Cells ◽  
Bacterial Cells ◽  
E Coli ◽  
Enhanced Production ◽  
Escherichia Coli Cells

Two genes involved in δ-guaiene biosynthesis in Aquilaria microcarpa, δ-guaiene synthase (GS) and farnesyl diphosphate synthase (FPS), were overexpressed in Escherichia coli cells. Immunoblot analysis revealed that the concentration of GS-translated protein was rather low in the cells transformed by solely GS while appreciable accumulation of the recombinant protein was observed when GS was coexpressed with FPS GS-transformed cells liberated only a trace amount of δ-guaiene (0.004 μg/mL culture), however, the concentration of the compound elevated to 0.08 μg/mL culture in the cells transformed by GS plus FPS δ-Guaiene biosynthesis was markedly activated when E. coli cells coexpressing GS and FPS were incubated in enriched Terrific broth, and the content of the compound increased to approximately 0.6 μg/mL culture. These results suggest that coexpression of FPS and GS in E. coli is required for efficient 6-guaiene production in the bacterial cells, and the sesquiterpene-producing activity of the transformant is appreciably enhanced in the nutrients-enriched medium.

Assessment of correlation between physiological states of Escherichia coli cells and their susceptibility to chlorine using flow cytometry

2013 ◽  
Vol 13 (4) ◽  
pp. 1056-1062 ◽  
Author(s):  
Saeid Rezaeinejad ◽  
Volodymyr Ivanov
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Growth Rates ◽  
Specific Growth ◽  
Bacterial Cells ◽  
Tetrazolium Chloride ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Cell Subpopulations ◽  
Specific Growth Rates

The physiological differences of individual cells of bacterial population may imply the existence of cell subpopulations with different sensitivity to chlorine, which may affect the efficiency of drinking water disinfection. The susceptibility of individual bacterial cells to chlorine was examined using flow cytometry. The inactivation of Escherichia coli cells by chlorine in the populations with specific growth rates of 0.2 and 0.9 h−1 was assessed using various viability indicators. Viability of bacterial cells was evaluated using membrane integrity propidium iodide (PI) dye, respiratory activity indicator of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and membrane potential probe of DiBAC4(3). It was found that there were cell subpopulations of E. coli with different levels of susceptibility to chlorine. E. coli cell population with higher specific growth rate was more susceptible to chlorine. The CT values for inactivation of 99% of cells (CT99) in populations of E. coli with specific growth rates of 0.9 and 0.2 h−1 were 0.06 and 0.09 mg min l−1, respectively. Flow cytometry could be used to study the sensitivity of bacterial cells to the chemical agents.

scholarly journals Stability of plasmid pBR322 within Escherichia coli cells

2021 ◽  
Vol 6 (1) ◽  
pp. 17-19
Author(s):  
Tahsin Tabassum ◽  
Tasmin Tabassum ◽  
Nafisa Tabassum ◽  
Syeda Muntaka Maniha ◽  
Rashed Noor
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Heat Shock ◽  
Plasmid Stability ◽  
Bacterial Cells ◽  
Plasmid Pbr322 ◽  
E Coli ◽  
Replica Plating ◽  
Escherichia Coli Cells ◽  
Pbr322 Plasmid

nsertion of plasmids into the bacterial cells is of great significance especially in course of the transfer of drug resistance, virulence and other traits. Retention of plasmids within the host bacteria is therefore an important factor for bacterial homeostasis. Current study inferred the pBR322 plasmid stability within the Escherichia coli competent cells. The calcium chloride heat shock method was used for the transformation purpose. The plasmid retention phenomenon was assessed through the replica plating. The results positively showed the plasmid retention within E. coli.

Exogenous Histidine as a Co-factor which Exacerbates the Toxicity of Hydrogen Peroxide in Cultured Mammalian and Bacterial Cells

1991 ◽  
Vol 19 (1) ◽  
pp. 68-70
Author(s):  
Giorgio Brandi ◽  
Piero Sestili ◽  
Andrea Guidarelli ◽  
Giuditta Fiorella Schiavano ◽  
Amedeo Albano ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Hydrogen Peroxide ◽  
Mammalian Cells ◽  
Culture Medium ◽  
Chinese Hamster ◽  
Bacterial Cells ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Casamino Acids

The killing of Escherichia coli cells by H2O2 is higher when exposure to the oxidant is performed in a complete culture medium, as compared to saline. Whereas MgSO4, CaCl2, thiamine or glucose, added separately or in combination with the saline, had no effect on the cytotoxic response to H2O2, the cytotoxicity appeared highly dependent upon the presence of the casamino acids in the incubation medium. One of these amino acids, histidine, was found to greatly augment the toxicity of H2O2 in E. coli. This effect of histidine was also observed in mammalian cells. In fact, both the cytoxicity and the DNA damage produced by H2O2 in Chinese hamster ovary (CHO) cells were significantly increased by this amino acid.

scholarly journals Biocontrol of Escherichia coli O157 with O157-Specific Bacteriophages

1999 ◽  
Vol 65 (9) ◽  
pp. 3767-3773 ◽  
Author(s):  
Indira T. Kudva ◽  
Srdjan Jelacic ◽  
Phillip I. Tarr ◽  
Philip Youderian ◽  
Carolyn J. Hovde
Keyword(s):  
Escherichia Coli ◽  
Liquid Culture ◽  
Plaque Formation ◽  
Multiplicity Of Infection ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Normal Flora ◽  
E Coli ◽  
Complete Lysis ◽  
Fresh Foods

ABSTRACT Escherichia coli O157 antigen-specific bacteriophages were isolated and tested to determine their ability to lyse laboratory cultures of Escherichia coli O157:H7. A total of 53 bovine or ovine fecal samples were enriched for phage, and 5 of these samples were found to contain lytic phages that grow on E. coliO157:H7. Three bacteriophages, designated KH1, KH4, and KH5, were evaluated. At 37 or 4°C, a mixture of these three O157-specific phages lysed all of the E. coli O157 cultures tested and none of the non-O157 E. coli or non-E. colicultures tested. These results required culture aeration and a high multiplicity of infection. Without aeration, complete lysis of the bacterial cells occurred only after 5 days of incubation and only at 4°C. Phage infection and plaque formation were influenced by the nature of the host cell O157 lipopolysaccharide (LPS). Strains that did not express the O157 antigen or expressed a truncated LPS were not susceptible to plaque formation or lysis by phage. In addition, strains that expressed abundant mid-range-molecular-weight LPS did not support plaque formation but were lysed in liquid culture. Virulent O157 antigen-specific phages could play a role in biocontrol of E. coli O157:H7 in animals and fresh foods without compromising the viability of other normal flora or food quality.

Insights into the persistence and phenotypic effects of the endogenous and cryptic plasmid pMF1 in its host strain Myxococcus fulvus 124B02

2020 ◽  
Vol 96 (3) ◽  
Author(s):  
Xiao-jing Chen ◽  
Zheng Zhang ◽  
Ya-jie Li ◽  
Li Zhuo ◽  
Duo-hong Sheng ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Cells ◽  
Fruiting Bodies ◽  
Long Term Effects ◽  
Laboratory Evolution ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
The Social ◽  
Cryptic Plasmids

ABSTRACT Many endogenous plasmids carry no noticeable benefits for their bacterial hosts, and the persistence of these ‘cryptic plasmids’ and their functional impacts are mostly unclear. In this study, we investigated these uncertainties using the social bacterium Myxococcus fulvus 124B02 and its endogenous plasmid pMF1. pMF1 possesses diverse genes that originated from myxobacteria, suggesting a longstanding co-existence of the plasmid with various myxobacterial species. The curing of pMF1 from 124B02 had almost no phenotypic effects on the host. Laboratory evolution experiments showed that the 124B02 strain retained pMF1 when subcultured on dead Escherichia coli cells but lost pMF1 when subcultured on living E. coli cells or on casitone medium; these results indicated that the persistence of pMF1 in 124B02 was environment-dependent. Curing pMF1 caused the mutant to lose the ability to predate and develop fruiting bodies more quickly than the pMF1-containing strain after they were subcultured on dead E. coli cells, which indicated that the presence of pMF1 in M. fulvus 124B02 has some long-term effects on its host. The results provide some new insights into the persistence and impacts of cryptic plasmids in their natural bacterial cells.

scholarly journals Artificial Septal Targeting of Bacillus subtilis Cell Division Proteins in Escherichia coli: an Interspecies Approach to the Study of Protein-Protein Interactions in Multiprotein Complexes

2008 ◽  
Vol 190 (18) ◽  
pp. 6048-6059 ◽  
Author(s):  
Carine Robichon ◽  
Glenn F. King ◽  
Nathan W. Goehring ◽  
Jon Beckwith
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Protein Interactions ◽  
Fluorescent Protein ◽  
Bacterial Cell Division ◽  
Protein Protein Interactions ◽  
Positive Interaction ◽  
E Coli ◽  
Multiprotein Complexes

ABSTRACT Bacterial cell division is mediated by a set of proteins that assemble to form a large multiprotein complex called the divisome. Recent studies in Bacillus subtilis and Escherichia coli indicate that cell division proteins are involved in multiple cooperative binding interactions, thus presenting a technical challenge to the analysis of these interactions. We report here the use of an E. coli artificial septal targeting system for examining the interactions between the B. subtilis cell division proteins DivIB, FtsL, DivIC, and PBP 2B. This technique involves the fusion of one of the proteins (the “bait”) to ZapA, an E. coli protein targeted to mid-cell, and the fusion of a second potentially interacting partner (the “prey”) to green fluorescent protein (GFP). A positive interaction between two test proteins in E. coli leads to septal localization of the GFP fusion construct, which can be detected by fluorescence microscopy. Using this system, we present evidence for two sets of strong protein-protein interactions between B. subtilis divisomal proteins in E. coli, namely, DivIC with FtsL and DivIB with PBP 2B, that are independent of other B. subtilis cell division proteins and that do not disturb the cytokinesis process in the host cell. Our studies based on the coexpression of three or four of these B. subtilis cell division proteins suggest that interactions among these four proteins are not strong enough to allow the formation of a stable four-protein complex in E. coli in contrast to previous suggestions. Finally, our results demonstrate that E. coli artificial septal targeting is an efficient and alternative approach for detecting and characterizing stable protein-protein interactions within multiprotein complexes from other microorganisms. A salient feature of our approach is that it probably only detects the strongest interactions, thus giving an indication of whether some interactions suggested by other techniques may either be considerably weaker or due to false positives.

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