Expression of the F plasmid ccd toxin–antitoxin system in Escherichia coli cells under nutritional stress

2006 ◽  
Vol 52 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Marisela Aguirre-Ramírez ◽  
Jesús Ramírez-Santos ◽  
Laurence Van Melderen ◽  
M Carmen Gómez-Eichelmann
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Stationary Phase ◽  
Plasmid Stability ◽  
Dna Gyrase ◽  
Nutritional Stress ◽  
Adaptive Mutation ◽  
F Plasmid ◽  
Adaptive Mutations ◽  
Escherichia Coli Cells

The ccd system of the F plasmid encodes CcdB, a protein toxic to DNA-gyrase, and CcdA, its antitoxin. The function attributed to this system is to contribute to plasmid stability by killing bacteria that lose the plasmid during cell division. However, the function of ccd in resting bacteria is not clear. Results presented show that ccd transcription increases as bacteria enter stationary phase and that the amount of the Ccd proteins is higher in bacteria under nutritional stress than in growing bacteria. Moreover, an increase in the frequency of Lac+ "adaptive" mutations was observed in stationary-phase bacteria that over-express the Ccd proteins.Key words: ccd system, nutritional stress, adaptive mutation.

scholarly journals Toxin Kid uncouples DNA replication and cell division to enforce retention of plasmid R1 in Escherichia coli cells

2014 ◽  
Vol 111 (7) ◽  
pp. 2734-2739 ◽  
Author(s):  
B. Pimentel ◽  
R. Nair ◽  
C. Bermejo-Rodriguez ◽  
M. A. Preston ◽  
C. A. Agu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Dna Replication ◽  
Plasmid R1 ◽  
Escherichia Coli Cells

scholarly journals Adaptive mutations produce resistance to ciprofloxacin.

1997 ◽  
Vol 41 (9) ◽  
pp. 2059-2060 ◽  
Author(s):  
C Riesenfeld ◽  
M Everett ◽  
L J Piddock ◽  
B G Hall
Keyword(s):  
Escherichia Coli ◽  
Resistance Mutations ◽  
Adaptive Mutations ◽  
Escherichia Coli Cells ◽  
Ciprofloxacin Resistance ◽  
Rifampin Resistance

Mutation to ciprofloxacin resistance continually occurred in nondividing Escherichia coli cells during a 7-day exposure to ciprofloxacin in agar, while no accumulation of rifampin resistance mutations was detected in those cells. We propose that the resistance mutations result from adaptive mutations, which preferentially produce phenotypes that promote growth in nondividing cells.

scholarly journals Induction of a DNA Nickase in the Presence of Its Target Site Stimulates Adaptive Mutation in Escherichia coli

2002 ◽  
Vol 184 (20) ◽  
pp. 5599-5608 ◽  
Author(s):  
Cesar Rodriguez ◽  
Joshua Tompkin ◽  
Jill Hazel ◽  
Patricia L. Foster
Keyword(s):  
Escherichia Coli ◽  
Single Strand ◽  
Target Site ◽  
Adaptive Mutation ◽  
Target Sequence ◽  
Induced Mutations ◽  
Single Base ◽  
Adaptive Mutations ◽  
E Coli ◽  
Nicking Enzyme

ABSTRACT Adaptive mutation to Lac+ in Escherichia coli strain FC40 depends on recombination functions and is enhanced by the expression of conjugal functions. To test the hypothesis that the conjugal function that is important for adaptive mutation is the production of a single-strand nick at the conjugal origin, we supplied an exogenous nicking enzyme, the gene II protein (gIIp) of bacteriophage f1, and placed its target sequence near the lac allele. When both gIIp and its target site were present, adaptive mutation was stimulated three- to fourfold. Like normal adaptive mutations, gIIp-induced mutations were recA+ and ruvC+ dependent and were mainly single-base deletions in runs of iterated bases. In addition, gIIp with its target site could substitute for conjugal functions in adaptive mutation. These results support the hypothesis that nicking at the conjugal origin initiates the recombination that produces adaptive mutations in this strain of E. coli, and they suggest that nicking may be the only conjugal function required for adaptive mutation.

SlyD-dependent nickel delivery limits maturation of [NiFe]-hydrogenases in late-stationary phase Escherichia coli cells

Metallomics ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 683-690 ◽  
Author(s):  
Constanze Pinske ◽  
Frank Sargent ◽  
R. Gary Sawers
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Late Stationary Phase ◽  
E Coli ◽  
Escherichia Coli Cells

The metallochaperone SlyD is essential for nickel delivery to hydrogenase in stationary phaseE. colicells.

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 Adaptive Mutagenesis at ebgR Is Regulated by PhoPQ

1998 ◽  
Vol 180 (11) ◽  
pp. 2862-2865 ◽  
Author(s):  
Barry G. Hall
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Error Correction ◽  
Regulatory System ◽  
Adaptive Mutation ◽  
Adaptive Mutagenesis ◽  
Adaptive Mutations ◽  
Nutritional Deprivation ◽  
Two Component ◽  
Stress Signals

ABSTRACT Adaptive mutations are mutations that occur in nondividing or very slowly dividing microbial cells during prolonged nonlethal selection and that are specific to the challenge of the selection in the sense that the only mutations that can be detected are those that provide a growth advantage to the cell. The phoPQ genes encode a two-component positively acting regulatory system that controls expression of at least 25 to 30 genes in Escherichia coliand Salmonella typhimurium. PhoPQ responds to a variety of environmental stress signals including Mg2+ starvation and nutritional deprivation. Here I show that disruption ofphoP or phoQ by Tn10dCam significantly reduces the adaptive mutation rate to ebgR, indicating that the adaptive mutagenesis machinery is regulated, directly or indirectly, byphoPQ. The finding that it is regulated implies that adaptive mutagenesis does not simply result from a failure of various error correction mechanisms during prolonged starvation.

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.

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