• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.355-356
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• 2000

Three 'stress probe' plasmids were constructed and characterized which utilize a green fluorescent protein (CFP) as a non-invasive reporter to elucidate Escherichia coli cellular stress responses in quiescent or 'resting' cells. Facile detection of cellular stress levels was achieved by fusion of three heat shock stress protein promoter elements, those of the heat shock transcription factor ${\sigma}^{32}$, pretense subunit ClpB, and chaperone DnaK, to the reporter gene $gfp_{uv}$. When perturbed by chemical or physical stress (such as heat shock, nutrient (amino acid) limitation, addition of IPTG, acetic acid, ethanol, phenol, antifoam, and salt (osmotic shock), the E. coli cells produced GFPuv which was easily detected from within the cells as emitted green fluorescence. A temporal and amplitudinal mapping of these responses was performed, demonstrating regions where quantitative delineation of cell stress was afforded.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1345-1353
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• 2007

The effect of salicylic acid(SA) on antioxidant system and protective mechanisms against UV-B induced oxidative stress was investigated in cucumber(Cucumis sativus L.) leaves. UV-B radiation and SA were applied separately or in combination to first leaves of cucumber seedlings, and dry matter accumulation, lipid peroxidation and activities of antioxidant enzymes were measured in both dose and time-dependant manner. UV-B exposure showed reduced levels of fresh weight and dry matter production, whereas SA treatment significantly increased them. SA noticeably recovered the UV-B induced inhibition of biomass production. UV-B stress also affected lipid peroxidation and antioxidant enzyme defense system. Malondialdehyde(MDA), a product of lipid peroxidation, was greatly increased under UV-B stress, showing a significant enhancement of a secondary metabolites, which may have antioxidative properties in cucumber leaves exposed to UV-B radiation. Combined application of UV-B and SA caused a moderate increase in lipid peroxidation. These results suggest that SA may mediate protection against oxidative stress. UV-B exposure significantly increased SOD, APX, and GR activity compared with untreated control plants. Those plants treated with 1.0 mM SA showed a similar pattern of changes in activities of antioxidant enzymes. SA-mediated induction of antioxidant enzyme activity may involve a protective accumulation of $H_2O_2$ against UV-B stress. Moreover, their activities were stimulated with a greater increase by UV-B+SA treatment. The UV-B+SA plants always presented higher values than UV-B and SA plants, considering the adverse effects of UV-B on the antioxidant cell system. ABA and JA, second messengers in signaling in response to stresses, showed similar mode of action in UV-B stress, supporting that they may be important in acquired stress tolerance. Based on these results, it can be suggested that SA may participates in the induction of protective mechanisms involved in tolerance to UV-B induced oxidative stress.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.168-179
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• 2015

We previously identified the rice gene, OsSAP, as an encoder of a highly conserved putative senescence-associated protein that was shown to have anti-apoptotic activity. To confirm the role of OsSAP in inducing abiotic stress tolerance in rice, we introduced OsSAP and AtBI-1, a plant homologue of Bax inhibitor-1, under the control of the CaMV 35S promoter into the rice genome through Agrobacterium-mediated transformation. The OsSAP transformants showed a similar chlorophyll index after salinity treatments with AtBI-1. Furthermore, we compared the effects of salinity stress on leaves and roots by examining the hormone levels of abscisic acid (ABA), jasmonic acid (JA), gibberellic acid (GA3), and zeatin in transformants compared to the control. With the exception of phytohormones, stress-induced changes in hormone levels putatively related to stress tolerance have not been investigated previously. Hormonal level analysis confirmed the lower rate of stress in the transformants compared to the control. The levels of ABA and JA in OsSAP and AtBI-1 transformants were similar, where stress rates increased after one week and decreased after a two week period of drought; there was a slightly higher accumulation compared to the control. However, a similar trend was not observed for the level of zeatin, as the decrease in the level of zeatin accumulation differed in both OsSAP and AtBI-1 transformants for all genotypes during the early period of salinity stress. The GA3 level was detected under normal conditions, but not under salinity stress.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.93-100
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• 2007

The effects of sudden changes of water temperature (WT) on the physiological response and hematological characteristics of the goldfish (Carassius auratus) were examined by manipulating WT in a flow through freshwater culture system with tanks. The WT was dropped from $15^{\circ}C$ to $10^{\circ}C$ within 1 hour and then returned to the original water temperature within 12 hours and maintained for 12 hours at the normal WT. The WT stress give continued for 3 days. Plasma levels of cortisol, glucose and lactic acid were higher in stress group than that of non-stressed group until 72 hours. However, The $Na^+,\;Cl^-$, osmolality and aspartate aminotransferase (AST) levels showed no significant differences in two groups. This results in stress group showed that goldfish exhibit "typical" physiological responses (in cortisol, glucose, lactic acid, hematocrit, red blood cell and hemoglobin) to the stress induced by WT changes.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1221-1223
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• 2010

본 논문에서는 한국인 아동의 우식치아로부터 S. mutans를 분리하고, acid stress하에서 분리한 S. mutans의 유전자의 발현의 변화를 분석하고자 하였다. 치아우식증의 주요한 요소로 작용하는 치태형성에 기여하는 glucan 및 fructan 합성에 관여하는 세포내 효소인 glucosyltransferase, glucosyltransferase, glucosyltransferase 및 fructosyltransferase의 발현량의 변화를 확인한 결과, lactic acid를 처리하지 않은 control의 경우보다 16배에서 3배까지 감소한 것을 확인할 수 있었다. Amino acid ABC transporter, adenylate kinase, fructokinase, 40k cell wall protein precursor에서는 모두 유전자의 발현량이 현저히 증가한 것을 볼 수 있었다. 이들 유전자는 acid stress에 관여하는 특이적 유전자로 추정된다.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.9-13
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• 1989

The effect of acetic acid concentration on the qualities of mayonnaise was studied. The rheological properties, emulsifying stability and color of the mayonnaise were determined by rotary viscometer, rotary shaker and centrifuge, and color and color difference meter, respectively. The rheological behavior of mayonnaise showed plastic behavior with yield stress and that of shear thinning. The yield stress and consistency index increased as the acetic acid concentration increased. The emulsion stability was lowest at 4% acetic acid concentration and highest at 1% acetic acid concentration. With the increase of the acetic acid concentration, lightness increased and yellowness decreased.

• KSBB Journal
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• v.8 no.5
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• pp.424-430
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• 1993

The anti-stress effect by the treatment of vitamin C was investigated in this study. The treatment of ascorbic acid in the presence of $Cu^{2+}$ion induced strong time- and dose-dependent degradation of hitamine, and also the addition of histamine accelerated time-dependent decomposition of ascorbic acid in vitro. The treatment of ascorbic acid in $ODS^{od}/_{od}$rats, which cannot synthesize ascorbic acid, significantly decreased the urinary histamine. The protreatment of ascorbic acid, dexamethasone and promethazine inhibited the lethal effect induced by immobilization stress, but that of dimethylsulfoxide did not. The addition of ascorbic and to a culture of spleen cells of $ODS^{od}/_{od}$rats significantly increased the Con A-dependent T lymphocyte proliferation.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.394-404
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• 2015

This study investigated the pharmacodynamics of betaine on the blood profile and short chain fatty acid levels in meat ducks exposed to heat wave. 400 heads of Cherry valley (Anasplatyrhynchos) meat ducks were completely randomized to 5 treatments (4 repetitions each), and were raised for 42 days. They were grouped into T1 (heat wave control group without betaine), T2 (betaine 400 ppm), T3 (betaine 800 ppm), T4 (betaine 1200 ppm), and T5 (normal control group without betaine). Compared to T1, the betaine addition groups showed higher body weight gain at shipment, with T3 showing the highest significant difference. For hematological indictors measured (red blood cells and platelets), the betaine addition groups showed significantly higher values than the heat wave control group. The pH of the former was lower but their electrolytes ($K^+$, $P^+$, and $Cl^-$) were significantly higher compared to the latter. For blood gas concentration, the former showed a significantly higher value than the latter. For the total short chain fatty acids, acetic acid, and propionic acid, the betaine addition groups and group fed broiler-high temperature diet showed higher values than the heat wave control group. On the other hand, the former showed significantly lower values in butyric acid, isobutyric acid, valeric acid, and isovaleric acid than the latter group. These results suggest that betaine has the pharmacodynamics that mediate heat stress, via the maintenance and control of the blood profile, osmotic pressure, gas concentration, and short chain fatty acid, of meat ducks under heat wave.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.718-724
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• 2008

Dissolved oxygen (DO) and shear stress have pronounced effects on hyaluronic acid (HA) production, yet various views persist about their effects on the molecular weight of HA. Accordingly, this study investigated the effects of DO and shear stress during HA fermentation. The results showed that both cell growth and HA synthesis were suppressed under anaerobic conditions, and the HA molecular mass was only $(1.22{\pm}0.02){\times}10^6 Da$. Under aerobic conditions, although the DO level produced no change in the biomass or HA yield, a high DO level favored the HA molecular mass, which reached a maximum value of $(2.19{\pm}0.05){\times}10^6 Da$ at 50% DO. Furthermore, a high shear stress delayed the rate of HA synthesis and decreased the HA molecular weight, yet had no clear effect on the HA yield. Therefore, a high DO concentration and mild shear environment would appear to be essential to enhance the HA molecular weight.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1681-1691
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• 2017

This study investigated the effect of proline addition on the salt tolerance of Tetragenococcus halophilus. Salt stress led to the accumulation of intracellular proline in T. halophilus. When 0.5 g/l proline was added to hyperhaline medium, the biomass increased 34.6% (12% NaCl) and 27.7% (18% NaCl) compared with the control (without proline addition), respectively. A metabolomic approach was employed to reveal the cellular metabolic responses and protective mechanisms of proline upon salt stress. The results showed that both the cellular membrane fatty acid composition and metabolite profiling responded by increasing unsaturated and cyclopropane fatty acid proportions, as well as accumulating some specific intracellular metabolites (environmental stress protector). Higher contents of intermediates involved in glycolysis, the tricarboxylic acid cycle, and the pentose phosphate pathway were observed in the cells supplemented with proline. In addition, addition of proline resulted in increased concentrations of many organic osmolytes, including glutamate, alanine, citrulline, N-acetyl-tryptophan, and mannitol, which may be beneficial for osmotic homeostasis. Taken together, results in this study suggested that proline plays a protective role in improving the salt tolerance of T. halophilus by regulating the related metabolic pathways.