• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1156-1162
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• 2010

During ethanol fermentation, bacterial strains may encounter various stresses, such as ethanol and acid shock, which adversely affect cell viability and the production of ethanol. Therefore, ethanologenic strains that tolerate abiotic stresses are highly desirable. Bacteria of the genus Deinococcus are extremely resistant to ionizing radiation, ultraviolet light, and desiccation, and therefore constitute an important pool of extreme resistance genes. The irrE gene encodes a general switch responsible for the extreme radioresistance of D. radiodurans. Here, we present evidence that IrrE, acting as a global regulator, confers high stress tolerance to a Zymomonas mobilis strain. Expression of the gene protected Z. mobilis cells against ethanol, acid, osmotic, and thermal shocks. It also markedly improved cell viability, the expression levels and enzyme activities of pyruvate decarboxylase and alcohol dehydrogenase, and the production of ethanol under both ethanol and acid stresses. These data suggest that irrE is a potentially promising gene for improving the abiotic stress tolerance of ethanologenic bacterial strains.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.484-493
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• 2012

BolA protein homologs are widely distributed in nature. In this report, we have studied for the first time YrbA, the only BolA homolog present in Escherichia coli, which we have renamed ibaG. We have constructed single and multiple ibaG mutants, and overexpressed ibaG in wild-type strains, in order to characterize this gene. The ibaG phenotypes are different from the bolA-associated round morphologies or growth profiles. Interestingly, ibaG and bolA single-and double-deletion mutants grow faster and have higher viabilities in rich media, whereas the overexpressed strains are significantly growth impaired. However, the mutant strains have lower viabilities than the wild type in the late stationary phase, indicating that both bolA and ibaG are important for survival in difficult growth conditions. bolA, as a transcription factor, binds to some promoters, but ibaG does not interact with the same DNA regions. We have determined that ibaG is transcribed in an operon with the murA gene, involved in the synthesis of peptidoglycan precursors. ibaG was also seen to change its mRNA expression pattern in response to acidic stress. ibaG may thus represent a new gene involved in cell resistance against acid stress.

• Animal cells and systems
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• v.4 no.1
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• pp.71-76
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• 2000

The aim of this study was to investigate expression patterns of the prolactin (PRL) and c-fos genes by 17$\beta$-estradiol (17$\beta$-E) and stress in the mouse pituitary. In the pituitary, the levels of PRL mRNA were found high with some fluctuation at 30, 50, and 90 min whereas the levels of PRL mRNA were low at 120 min when ovariectomized female mice were injected with 17$\beta$-E or vehicle. PRL mRNA levels began to increase again at 4 h and remained high up to 24 h only in the 17$\beta$-E- treated mice. The overall changes in c-fos mRNA by 17$\beta$-E were very similar to those in PRL mRNA in the pituitary. Subsequent study revealed that these high initial levels of PRL and c-fos mRNAs were caused by stress during Injection, not by 17$\beta$-E, since vehicle injection alone into the ovariectomized mice could increase the levels of PRL and c-fos mRNAs. The stress-induced elevations of PRL and c-fos mRNAs were inhibited by bromocriptin, a dopamine agonist, suggesting that the dopaminergic system is involved in the action route of injection stress. In addition, the induced levels of c-fos mRNA by 17$\beta$-E and stress in the pituitary were very low compared with those in the uterus. The time course changes in c-fos mRNA level were different between the pituitary and uterus. Taken together, these data indicate that PRL and c-tos gene expression in the pituitary are regulated by 17$\beta$-E and stress in a parallel manner, supporting the notion that c-Fos plays a role in regulation of PRL gene expression.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1063-1066
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• 2004

The rpoS gene product is a global transcriptional factor, which is involved in bacterial survival under various stress conditions. An rpoS-homologous gene was cloned from a septicemia-causing pathogenic Vibrio vulnificus. Introduction of this gene as a multicopy plasmid into various E. coli strains displayed functional complementation, for examples, increased survivability of an rpoS-defective E. coli cell and induction of known $\delta^S$-dependent, stress-responding promoters of E. coli genes.

• Journal of Microbiology
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• v.34 no.2
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• pp.137-143
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• 1996

We isolated a promoter inducible by paraquat, a superoxide-generating agent, from Escherichia coli using a promoter-probing plasmid pRS415. From sequence analysis we found out the promoter is for fpr ENCODING nadph : ferredoxin oxidoreductase. We constructed on operon fusion of lacZ gene with fpr promoter to monitor the expression of the gene in the single-copy state. LacZ expression generators, menadione and plumbagin, also induced the expression of .betha.-galactosidase in the fusion strain. On the other hand, no significant induction was observed by treatment with hydrogen peroxide, ethanol, and heat shock. Induction of .betha.-galactosidase was significantly reduced by introducing a .DELTA. sox 8 :: cat of soxS3 :: Tn10 mutation into the fusion strain, indicating that fpr gene is a member of the soxRS regulon. The transcriptional start site was determined by primer extension analysis. Possible roles of fpr induction in superoxide stress were discussed.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.99.1-100
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• 2003

E. intermedium Blocontrol activity of a P. chlororaphis rhizobacteium O6, depends to the synthesis of extracellular secondary metabolites and exoenzymes, thought to antagonize the pathogenicity of a variety of phytopathogenic fungi. The production of secondary metabolites and exoenzymes in O6, depends essentially on the GacS-mediated signal transduction pathway, which activates largely unknown signal transduction pathway. To exploit the GacS-mediated signal transdcution pathway involved in activation of ph genes that are necessary for biosynthesis of phenazine from P. chlororaphis O6, we cloned and sequenced the phz operon, rpoS gene encoding stationary specific sigma factor, ppx gene encoding polyphosphatase, and lon gene encoding ion protease. Expression of each gene in wild type and GacS mutant were analyzed by RT-PCR. Transcripts from rpoS, phzI enconing acylhomoserine lactone (AHL) synthase, and ph structural genes in the GacS mutant were reduced in each of these growth phases compared to the wild type. The GacS or Lon mutant was found to be deficient in the production of phenzines, exoenzymes, and the acylhomoserine lactone. These mutants were not complemented by ph operon and addition of exogenous AHL. These results indicate that the GacS global regulatory systems controls phenazine production at multiple levels. Future research will focus to identifying the GacS-mediated regulatory cascade involving in production of phenazine in P. chlororaphis.

• Journal of Korean Biological Nursing Science
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• v.18 no.4
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• pp.305-317
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• 2016

Purpose: Recent studies demonstrated disruption of the circadian clock gene is associated with the development of obesity and metabolic syndrome. Obesity is often caused by the high calorie intake, In addition, the chronic stress tends to contribute to the increased risk for obesity. To evaluate the molecular mechanisms, we examined the expression of circadian clock genes in high fat diet-induced mice models with the chronic stress. Methods: C57BL/6J mice were fed with a 45% or 60% high fat diet for 8 weeks. Daily immobilization stress was applied to mice fed with a 45% high fat for 16 weeks. We compared body weight, food consumption, hormone levels and metabolic variables in blood. mRNA expression levels of metabolic and circadian clock genes in both fat and liver were determined by quantitative RT-PCR. Results: The higher fat content induced more severe hyperglycemia, hyperlipidemia and hyperinsulinemia, and these results correlated with their relevant gene expressions in fat and liver tissues. Chronic stress had only minimal effects on metabolic variables, but it altered the expression patterns of metabolic and circadian clock genes. Conclusion: These results suggest that the fat metabolism regulates the function of the circadian clock genes in peripheral tissues, and stress hormones may contribute to its regulation.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.53-57
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• 2011

The MuSI is known as a multiple stress resistant gene with several lines. A previous study using RT-PCR showed that the expression of MuSI gene in tobacco plant induced its tolerance to Cd stress. This study was conducted to examine the enhanced Cd tolerance of the MuSI transgenic tobacco plant through germination test and to understand the role of the involved antioxidant enzymes for the exhibited tolerance. Germination rate of MuSI transgenic tobacco was more than 10% higher than that of wild-type tobacco, and seedlings of MuSI transgenic tobacco grew up to 1.6 times larger and greener than seedlings of wild-type tobacco at 200 and 300 ${\mu}M$ Cd. From the third to the fifth day, CAT activities at 100 and 200 ${\mu}M$ Cd and APX activities at 100, 200 and 300 ${\mu}M$ Cd of MuSI transgenic tobacco were up to two times higher than those of wild-type tobacco. MuSI gene is shown to enhance the activities of antioxidant enzymes resulting in higher tolerance to oxidative stress compared with the control plant.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1416-1421
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• 2006

We identified a gene encoding the N-acetylmuramoyl L-alanine amidase (amiB) of Vibrio anguillarum, which catalyzes the degradation of peptidoglycan in bacteria. The entire open reading frame (ORF) of the amiB gene was composed of 1,722 nucleotides and 573 amino acids. The deduced amino acid sequence of AmiB showed a modular structure with two main domains; an N-terminal region exhibiting an Ami domain and three highly conserved, continuously repeating LysM domains in the C-terminal portion. An amiB mutant was constructed by homologous recombination to study the biochemical function of the AmiB protein in V. anguillarum. Transmission electron microscopy (TEM) revealed morphological differences, and that the mutant strain formed trimeric and tetrameric unseparated cells, suggesting that this enzyme is involved in the separation of daughter cells after cell division. Furthermore, inactivation of the amiB gene resulted in a marked increase of sensitivity to oxidative stress and organic acids.

• Biomedical Science Letters
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• v.17 no.3
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• pp.231-238
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• 2011

During pregnancy, stress induces maternal glucocorticoid secretion, which in turn is known to affect structural malformation, retardation of growth, reduced birth weight of the fetus. As Hox genes are master transcription factors which fulfill critical roles in embryonic development, we aimed to explore the possibility that alterations of the Hox gene expression might be involved in stress-induced malformation. The pregnant mice were injected with dexamethasone at a dose of 1 mg/kg or 10 mg/kg on day 7.5, 8.5 and 9.5 p.c. (post coitum), as well as saline as control. Embryos of E11.5 and E18.5 were obtained by sacrificing pregnant animals. Weight and crown-rump length (CRL) were measured. RT-PCR was performed to examine the Hox gene expression levels. Embryos given dexamethasone at day 7.5~9.5 p.c. had small CRL and weighed less both in E11.5 and E18.5. The percentage of embryos showing abnormalities was high in groups received high dose of dexamethasone. To define the molecular basis for abnormal embryonic development, we analyzed the Hox gene expression pattern and found that many Hox genes display altered expression. Effects of prenatal dexamethasone treatment on embryonic development might be associated with the aberrant Hox gene expression.