The Mechanosensitive Channel Protein MscL Is Targeted by the SRP to The Novel YidC Membrane Insertion Pathway of Escherichia coli

Abstract This study investigates the physiological manifestation of adaptive evolutionary change in 12 replicate populations of Escherichia coli that were propagated for 2000 generations in a glucose-limited environment. Representative genotypes from each population were assayed for fitness relative to their common ancestor in the experimental glucose environment and in 11 novel single-nutrient environments. After 2000 generations, the 12 derived genotypes had diverged into at least six distinct phenotypic classes. The nutrients were classified into four groups based upon their uptake physiology. All 12 derived genotypes improved in fitness by similar amounts in the glucose environment, and this pattern of parallel fitness gains was also seen in those novel environments where the limiting nutrient shared uptake mechanisms with glucose. Fitness showed little or no consistent improvement, but much greater genetic variation, in novel environments where the limiting nutrient differed from glucose in its uptake mechanisms. This pattern of fitness variation in the novel nutrient environments suggests that the independently derived genotypes adapted to the glucose environment by similar, but not identical, changes in the physiological mechanisms for moving glucose across both the inner and outer membranes.

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Characterization of novel ybjG and dacC variants in Escherichia coli

Journal of Medical Microbiology ◽

10.1099/jmm.0.062893-0 ◽

2013 ◽

Vol 62 (11) ◽

pp. 1728-1734 ◽

Cited By ~ 4

Author(s):

Dongguo Wang ◽

Enping Hu ◽

Jiayu Chen ◽

Xiulin Tao ◽

Katelyn Gutierrez ◽

...

Keyword(s):

Escherichia Coli ◽

Multiple Drug Resistance ◽

Multiple Drug ◽

The Novel ◽

Conventional Pcr ◽

E Coli ◽

Novel Variants ◽

Restriction Sites ◽

Genetic Structures

A total of 69 strains of Escherichia coli from patients in the Taizhou Municipal Hospital, China, were isolated, and 11 strains were identified that were resistant to bacitracin, chloramphenicol, tetracycline and erythromycin. These strains were PCR positive for at least two out of three genes, ybjG, dacC and mdfA, by gene mapping with conventional PCR detection. Conjugation experiments demonstrated that these genes existed in plasmids that conferred resistance. Novel ybjG and dacC variants were isolated from E. coli strains EC2163 and EC2347, which were obtained from the sputum of intensive care unit patients. Genetic mapping showed that the genes were located on 8200 kb plasmid regions flanked by EcoRI restriction sites. Three distinct genetic structures were identified among the 11 PCR-positive strains of E. coli, and two contained the novel ybjG and dacC variants. The putative amino acid differences in the ybjG and dacC gene variants were characterized. These results provide evidence for novel variants of ybjG and dacC, and suggest that multiple drug resistance in hospital strains of E. coli depends on the synergistic function of ybjG, dacC and mdfA within three distinct genetic structures in conjugative plasmids.

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The Novel Property of Heptapeptide of Microcin C7 in Affecting the Cell Growth of Escherichia coli

Molecules ◽

10.3390/molecules22030432 ◽

2017 ◽

Vol 22 (3) ◽

pp. 432 ◽

Cited By ~ 4

Author(s):

Rensen Ran ◽

Huan Zeng ◽

Dong Zhao ◽

Ruiyuan Liu ◽

Xia Xu

Keyword(s):

Escherichia Coli ◽

Cell Growth ◽

The Novel

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Isolation of the novel regulatory mutants of the tryptophan biosynthetic system in Escherichia coli

MGG Molecular & General Genetics ◽

10.1007/bf00341866 ◽

1968 ◽

Vol 102 (1) ◽

pp. 15-26 ◽

Cited By ~ 20

Author(s):

Yasunobu Kano ◽

Aizo Matsushiro ◽

Yoshiro Shimura

Keyword(s):

Escherichia Coli ◽

The Novel ◽

Regulatory Mutants

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Plasmid DNA Production in Proteome-Reduced Escherichia coli

Microorganisms ◽

10.3390/microorganisms8091444 ◽

2020 ◽

Vol 8 (9) ◽

pp. 1444

Author(s):

Mitzi de la Cruz ◽

Elisa A. Ramírez ◽

Juan-Carlos Sigala ◽

José Utrilla ◽

Alvaro R. Lara

Keyword(s):

Escherichia Coli ◽

Plasmid Dna ◽

Type Strain ◽

Wild Type Strain ◽

The Novel ◽

Wild Type ◽

Batch Mode ◽

Cell Factories ◽

Starting Point ◽

In The Wild

The design of optimal cell factories requires engineering resource allocation for maximizing product synthesis. A recently developed method to maximize the saving in cell resources released 0.5% of the proteome of Escherichia coli by deleting only three transcription factors. We assessed the capacity for plasmid DNA (pDNA) production in the proteome-reduced strain in a mineral medium, lysogeny, and terrific broths. In all three cases, the pDNA yield from biomass was between 33 and 53% higher in the proteome-reduced than in its wild type strain. When cultured in fed-batch mode in shake-flask, the proteome-reduced strain produced 74.8 mg L−1 pDNA, which was four times greater than its wild-type strain. Nevertheless, the pDNA supercoiled fraction was less than 60% in all cases. Deletion of recA increased the pDNA yields in the wild type, but not in the proteome-reduced strain. Furthermore, recA mutants produced a higher fraction of supercoiled pDNA, compared to their parents. These results show that the novel proteome reduction approach is a promising starting point for the design of improved pDNA production hosts.

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Temperature-sensitive mutants of MscL mechanosensitive channel

The Journal of Biochemistry ◽

10.1093/jb/mvz035 ◽

2019 ◽

Vol 166 (3) ◽

pp. 281-288 ◽

Cited By ~ 1

Author(s):

Naoto Owada ◽

Megumi Yoshida ◽

Kohei Morita ◽

Kenjiro Yoshimura

Keyword(s):

Escherichia Coli ◽

Amino Acids ◽

Structural Change ◽

Cell Growth ◽

Thermodynamic Stability ◽

Transmembrane Helix ◽

Mechanosensitive Channel ◽

Temperature Sensitive ◽

Temperature Sensitive Mutants ◽

Membrane Stretching

Abstract MscL is a mechanosensitive channel that undergoes a global conformational change upon application of membrane stretching. To elucidate how the structural stability and flexibility occur, we isolated temperature-sensitive (Ts) mutants of Escherichia coli MscL that allowed cell growth at 32°C but not at 42°C. Two Ts mutants, L86P and D127V, were identified. The L86P mutation occurred in the second transmembrane helix, TM2. Substitution of residues neighbouring L86 with proline also led to a Ts mutation, but the substitution of L86 with other amino acids did not result in a Ts phenotype, indicating that the Ts phenotype was due to a structural change of TM2 helix by the introduction of a proline residue. The D127V mutation was localized in the electrostatic belt of the bundle of cytoplasmic helices, indicating that stability of the pentameric bundle of the cytoplasmic helix affects MscL structure. Together, this study described a novel class of MscL mutations that were correlated with the thermodynamic stability of the MscL structure.

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