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- Heat Shock Causes Oxidative Stress and Induces a Variety of Cell Rescue Proteins in Saccharomyces cerevisiae KNU5377
- Il-Sup Kim , Hye-Youn Moon , Hae-Sun Yun , Ingnyol Jin
- J. Microbiol. 2006;44(5):492-501.
- DOI: https://doi.org/2449 [pii]
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Abstract
- In this study, we attempted to characterize the physiological response to oxidative stress by heat shock in Saccharomyces cerevisiae KNU5377 (KNU5377) that ferments at a temperature of 40°C. The KNU5377 strain evidenced a very similar growth rate at 40°C as was recorded under normal conditions. Unlike the laboratory strains of S. cerevisiae, the cell viability of KNU5377 was affected slightly under 2 hours of heat stress conditions at 43°C. KNU5377 evidenced a time-dependent increase in hydroperoxide levels, carbonyl contents, and malondialdehyde (MDA), which increased in the expression of a variety of cell rescue proteins containing Hsp104p, Ssap, Hsp30p, Sod1p, catalase, glutathione reductase, G6PDH, thioredoxin, thioredoxin peroxidase (Tsa1p), Adhp, Aldp, trehalose and glycogen at high temperature. Pma1/2p, Hsp90p and H+-ATPase expression levels were reduced as the result of exposure to heat shock. With regard to cellular fatty acid composition, levels of unsaturated fatty acids (USFAs) were increased significantly at high temperatures (43°C), and this was particularly true of oleic acid (C18:1). The results of this study indicated that oxidative stress as the result of heat shock may induce a more profound stimulation of trehalose, antioxidant enzymes, and heat shock proteins, as well as an increase in the USFAs ratios. This might contribute to cellular protective functions for the maintenance of cellular homeostasis, and may also contribute to membrane fluidity.
- Synthesis and Requirement of Escherichia coli Heat Shock Proteins GroEL and DnaK for Survival under Phenol Stress Conditions
- Jeon, Taeck Joong , Lee, Kil Jae
- J. Microbiol. 1998;36(1):26-33.
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Abstract
- Exposure of Escherichia coli strain MC4100 to various concentrations of phenol at temperatures higher than 20℃ led to induction of stress proteins such as GroEL and DnaK, as analyzed by SDS-PAGE and Western blotting methods. The optimum range of phenol concentration for the induction of GroEL and DnaK was slightly different at each temperature of bacterial growth and phenol treatment. The level of GroEL increased as the temperatures of growth and phenol treatment were increased from 30℃ to 40℃. The level of induced FroEL was maximal in the wild type cells which had been grown and treated by 2000㎍/㎖ phenol at 40℃. In contrast to GroEL, the level of DnaK decreased as the temperatures of growth and phenol treatment were increased from 25℃ to 40℃. Dnak was maximally induced in the cells grown and exposed to 1000㎍/㎖ phenol at 25℃. In rpoH mutant cells KY1601, GroEL was not additionally induced by phenol treatment and DnaK was not even detectable under normal and phenol stress conditions. Viability of cells under the same conditions of phenol treatment showed that the phenol resistance in much more induced in wild type cells than rpoH mutant cells. These results suggest that the induction of GroEL and DnaK is required for the enhanced viability of cells under conditions of phenol stress.
- Stress-shock Response of a Methylotrophic Bacterium Methylovorus sp. strain SS1 DSM 11726
- Jong H. Park , Si W. Kim , Eungbin Kim , Young T. Ro , Young M. Kim
- J. Microbiol. 2001;39(3):162-167.
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Abstract
- Methylovorus sp. strain SS1 DSM 11726 was found to grow continuously when it was transferred from 30 C to 40 C and 43 C. A shift in growth temperature from 30 C to 45 C, 47 C and 50 C reduced the viability of the cell population by more than 10^2 , 10^3 and 10^5 folds, respectively, after 1 h cultivation. Cells transferred to 47 C and 50 C after preincubation for 15 min at 43 C, however, exhibited 10-fold increase in viability. It was found that incubation for 15 min at 40 C of Methylovorus sp. strain SS1 grown at 30 C was sufficient to accelerate the synthesis of a specific subset of proteins. The major heat shock proteins had apparent molecular masses of 90, 70, 66, 60, and 58 kDa. The 60 and 58 kDa proteins were found to cross-react with the antiserum raised against GroEL protein. The heat shock response persisted for over 1 h. The shock proteins were stable for 90 min in the cell. Exposure of the cells to methanol induced proteins identical to the heat shock proteins. Addition of ethanol induced a unique protein with a molecular mass of about 40 kDa in addition to the heat-induced proteins. The proteins induced in paraquat-treated cells were different from the heat shock proteins, except the 70 and 60 kDa proteins.
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