scholarly journals Induction of DnaK and GroEL heat shock proteins by fluoroquinolones in Escherichia coli.

1997 ◽  
Vol 41 (1) ◽  
pp. 193-195 ◽  
Author(s):  
T Mizushima ◽  
M Matsuo ◽  
K Sekimizu
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Dna Relaxation ◽  
Cellular Dna ◽  
Shock Proteins ◽  
Kinetics Of

Various fluoroquinolones (norfloxacin, enoxacin, ofloxacin, levofloxacin, and sparfloxacin) induce DnaK and GroEL heat shock proteins in Escherichia coli. The induction is transient, consistent with the kinetics of cellular DNA relaxation. The concentrations of fluoroquinolones required for induction are similar to those required for DNA relaxation and much higher than those required for cell death.

scholarly journals Functional Analysis of Genes Comprising the Locus of Heat Resistance in Escherichia coli

2017 ◽  
Vol 83 (20) ◽  
Author(s):  
Ryan Mercer ◽  
Oanh Nguyen ◽  
Qixing Ou ◽  
Lynn McMullen ◽  
Michael G. Gänzle
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Heat Resistance ◽  
Growth Phase ◽  
Genomic Island ◽  
Enteric Bacteria ◽  
Content Type ◽  
E Coli ◽  
Shock Proteins

ABSTRACT The locus of heat resistance (LHR) is a 15- to 19-kb genomic island conferring exceptional heat resistance to organisms in the family Enterobacteriaceae, including pathogenic strains of Salmonella enterica and Escherichia coli. The complement of LHR-comprising genes that is necessary for heat resistance and the stress-induced or growth-phase-induced expression of LHR-comprising genes are unknown. This study determined the contribution of the seven LHR-comprising genes yfdX1 GI, yfdX2, hdeD GI, orf11, trx GI, kefB, and psiE GI by comparing the heat resistances of E. coli strains harboring plasmid-encoded derivatives of the different LHRs in these genes. (Genes carry a subscript “GI” [genomic island] if an ortholog of the same gene is present in genomes of E. coli.) LHR-encoded heat shock proteins sHSP20, ClpKGI, and sHSPGI are not sufficient for the heat resistance phenotype; YfdX1, YfdX2, and HdeD are necessary to complement the LHR heat shock proteins and to impart a high level of resistance. Deletion of trx GI, kefB, and psiE GI from plasmid-encoded copies of the LHR did not significantly affect heat resistance. The effect of the growth phase and the NaCl concentration on expression from the putative LHR promoter p2 was determined by quantitative reverse transcription-PCR and by a plasmid-encoded p2:GFP promoter fusion. The expression levels of exponential- and stationary-phase E. coli cells were not significantly different, but the addition of 1% NaCl significantly increased LHR expression. Remarkably, LHR expression in E. coli was dependent on a chromosomal copy of evgA. In conclusion, this study improved our understanding of the genes required for exceptional heat resistance in E. coli and factors that increase their expression in food. IMPORTANCE The locus of heat resistance (LHR) is a genomic island conferring exceptional heat resistance to several foodborne pathogens. The exceptional level of heat resistance provided by the LHR questions the control of pathogens by current food processing and preparation techniques. The function of LHR-comprising genes and their regulation, however, remain largely unknown. This study defines a core complement of LHR-encoded proteins that are necessary for heat resistance and demonstrates that regulation of the LHR in E. coli requires a chromosomal copy of the gene encoding EvgA. This study provides insight into the function of a transmissible genomic island that allows otherwise heat-sensitive enteric bacteria, including pathogens, to lead a thermoduric lifestyle and thus contributes to the detection and control of heat-resistant enteric bacteria in food.

scholarly journals In situ localization of heat-shock proteins and cell death labelling in the salivary gland of acaricide-treated honeybee larvae

Apidologie ◽  
2006 ◽  
Vol 37 (5) ◽  
pp. 507-516 ◽  
Author(s):  
Elaine C.M. Silva-Zacarin ◽  
Ales Gregorc ◽  
Regina L.M. Silva de Moraes
Keyword(s):  
Cell Death ◽  
Salivary Gland ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Shock Proteins

scholarly journals Immunomodulation of function of small heat shock proteins prevents their assembly into heat stress granules and results in cell death at sublethal temperatures

2004 ◽  
Vol 41 (2) ◽  
pp. 269-281 ◽  
Author(s):  
Sergey Miroshnichenko ◽  
Joanna Tripp ◽  
Uta zur Nieden ◽  
Dieter Neumann ◽  
Udo Conrad ◽  
...  
Keyword(s):  
Cell Death ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Stress Granules ◽  
Small Heat Shock Proteins ◽  
Shock Proteins
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