Repression of the aroF promoter by the TyrR repressor in Escherichia coli K-12: role of the 'upstream' operator site

1988 ◽  
Vol 2 (3) ◽  
pp. 377-383 ◽  
Author(s):  
C. S. Cobbett
Keyword(s):  
Escherichia Coli ◽  
K 12 ◽  
Operator Site

scholarly journals Regulatory Role of PlaR (YiaJ) for Plant Utilization in Escherichia coli K-12

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tomohiro Shimada ◽  
Yui Yokoyama ◽  
Takumi Anzai ◽  
Kaneyoshi Yamamoto ◽  
Akira Ishihama
Keyword(s):  
Escherichia Coli ◽  
Genetic System ◽  
Regulatory Role ◽  
E Coli ◽  
Warm Blooded Animal ◽  
Plant Utilization ◽  
K 12

AbstractOutside a warm-blooded animal host, the enterobacterium Escherichia coli K-12 is also able to grow and survive in stressful nature. The major organic substance in nature is plant, but the genetic system of E. coli how to utilize plant-derived materials as nutrients is poorly understood. Here we describe the set of regulatory targets for uncharacterized IclR-family transcription factor YiaJ on the E. coli genome, using gSELEX screening system. Among a total of 18 high-affinity binding targets of YiaJ, the major regulatory target was identified to be the yiaLMNOPQRS operon for utilization of ascorbate from fruits and galacturonate from plant pectin. The targets of YiaJ also include the genes involved in the utilization for other plant-derived materials as nutrients such as fructose, sorbitol, glycerol and fructoselysine. Detailed in vitro and in vivo analyses suggest that L-ascorbate and α-D-galacturonate are the effector ligands for regulation of YiaJ function. These findings altogether indicate that YiaJ plays a major regulatory role in expression of a set of the genes for the utilization of plant-derived materials as nutrients for survival. PlaR was also suggested to play protecting roles of E. coli under stressful environments in nature, including the formation of biofilm. We then propose renaming YiaJ to PlaR (regulator of plant utilization).

Role of respiration and glutathione in cadmium-induced oxidative stress in Escherichia coli K-12

2007 ◽  
Vol 189 (3) ◽  
pp. 271-278 ◽  
Author(s):  
Catarina C. Pacheco ◽  
João F. Passos ◽  
A. Rita Castro ◽  
Pedro Moradas-Ferreira ◽  
Paolo De Marco
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
K 12

scholarly journals Interaction between complement subcomponent C1q and bacterial lipopolysaccharides

1989 ◽  
Vol 257 (3) ◽  
pp. 865-873 ◽  
Author(s):  
A Zohair ◽  
S Chesne ◽  
R H Wade ◽  
M G Colomb
Keyword(s):  
Escherichia Coli ◽  
Chemical Modification ◽  
Essential Role ◽  
Wild Strain ◽  
E Coli ◽  
Diethyl Pyrocarbonate ◽  
Direct Binding ◽  
Bacterial Lipopolysaccharides ◽  
K 12

The heptose-less mutant of Escherichia coli, D31m4, bound complement subcomponent C1q and its collagen-like fragments (C1qCLF) with Ka values of 1.4 x 10(8) and 2.0 x 10(8) M-1 respectively. This binding was suppressed by chemical modification of C1q and C1qCLF using diethyl pyrocarbonate (DEPC). To investigate the role of lipopolysaccharides (LPS) in this binding, biosynthetically labelled [14C]LPS were purified from E. coli D31m4 and incorporated into liposomes prepared from phosphatidylcholine (PC) and phosphatidylethanolamine (PE) [PC/PE/LPS, 2:2:1, by wt.]. Binding of C1q or its collagen-like fragments to the liposomes was estimated via a flotation test. These liposomes bound C1q and C1qCLF with Ka values of 8.0 x 10(7) and 2.0 x 10(7) M-1; this binding was totally inhibited after chemical modification of C1q and C1qCLF by DEPC. Liposomes containing LPS purified from the wild-strain E. coli K-12 S also bound C1q and C1qCLF, whereas direct binding of C1q or C1qCLF to the bacteria was negligible. Diamines at concentrations which dissociate C1 into C1q and (C1r, C1s)2, strongly inhibited the interaction of C1q or C1qCLF with LPS. Removal of 3-deoxy-D-manno-octulosonic acid (2-keto-3-deoxyoctonic acid; KDO) from E. coli D31m4 LPS decreases the binding of C1qCLF to the bacteria by 65%. When this purified and modified LPS was incorporated into liposomes, the C1qCLF binding was completely abolished. These results show: (i) the essential role of the collagen-like moiety and probably its histidine residues in the interaction between C1q and the mutant D31m4; (ii) the contribution of LPS, particularly the anionic charges of KDO, to this interaction.

THE INFLUENCE OF THE PO1A1 MUTATION UPON RECOMBINATION IN ESCHERICHIA COLI K12

1979 ◽  
Vol 21 (3) ◽  
pp. 423-428 ◽  
Author(s):  
Barry W. Glickman ◽  
Tineke Rutgers
Keyword(s):  
Escherichia Coli ◽  
Dna Polymerase ◽  
Genetic Recombination ◽  
Dna Polymerase I ◽  
Multiple Gene ◽  
E Coli ◽  
Recombinational Process ◽  
K 12 ◽  
Polymerase I

Genetic recombination in Escherichia coli is a highly regulated process involving multiple gene products. We have investigated the role of DNA polymerase I in this process by studying the effect of the po1A1 mutation upon DNA transfer and conjugation in otherwise isogenic suppressor-free strains of E. coli K-12. It was found that the po1A1 mutation greatly reduces recombination in Hfr crosses (a factor of 20 in Po1+ × Po1A1 crosses and more than a factor of 100 in Po1A1 × Po1A1 crosses). However, since the po1A1 mutation reduces the strains capacity to act as a recipient for an F-prime and the analysis of recombination transfer gradients revealed no differences between Po1+ and Po1− strains, it is concluded that DNA polymerase I probably affects the transfer and/or stability of donor DNA rather than the recombinational process itself.

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