• Journal of Veterinary Clinics
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• v.16 no.1
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• pp.108-117
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• 1999

Hepatic tumorigenesis was induced by ad libitum feeding of diethylnitrosamine (DEN) only. We could also observe hepatic tumor induction in 100% of DEN treated rats without any other cocarcinogen. The liver specific enzyme activities (AST, ALT, ALP, ${\gamma}$-GTP) were significantly increased (P<0.05) in all treated groups compared to control and induced apoptosis groups. In histopathological analysis, the altered foci, hyperplastic nodules, neoplastic nodules, adenomas and carcinomas were observed in liver tumors induced by administration of DEN in rats. Lipopolysaccharide-induced apoptosis in D-galactosamine sensitized mice was investigated in hepatocytes in vivo. Typical morphological changes of apoptosis were detectable in liver 12 hr and 24 hr after the injection of Lipopolysaccharide (5 $\mu\textrm{g}$) and D-galactosamine (20 mg) to mice. It was suggested that organ specific enzyme activities and morphological findings might be very useful for understanding the role of hepatic tumorigenesis including the apoptotic cell death.

• Journal of Microbiology and Biotechnology
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• v.21 no.4
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• pp.341-346
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• 2011

To study the effects of salinity-sodicity on bacterial population and enzyme activities, soil samples were collected from the Bay of Yellow Sea, Incheon, South Korea. In the soils nearest to the coastline, pH, electrical conductivity ($EC_e$), sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) were greater than the criteria of saline-sodic soil, and soils collected from sites 1.5-2 km away from the coastline were not substantially affected by the intrusion and spray of seawater. Halotolerant bacteria showed similar trends, whereas non-tolerant bacteria and enzymatic activities had opposite trends. Significant positive correlations were found between EC, exchangeable $Na^+$, and pH with SAR and ESP. In contrast, $EC_e$, SAR, ESP, and exchangeable $Na^+$ exhibited significant negative correlations with bacterial populations and enzyme activities. The results of this study indicate that the soil chemical variables related with salinity-sodicity are significantly related with the sampling distance from the coastline and are the key stress factors, which greatly affect microbial and biochemical properties.

• The Korean Journal of Food And Nutrition
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• v.21 no.3
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• pp.328-335
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• 2008

The principal objective of this study was to assess the effects of chitosan oligosaccharide supplementation on the improvement of blood glucose, lipid components and enzyme activities in the serum of streptozotocin(STZ, 55 mg/kg B.W., I.P. injection)-induced hyperglycemic rats fed on experimental diets for 5 weeks. The concentrations of blood glucose, total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, free cholesterol, cholesteryl ester ratio, triglycerides(TG) and phospholipids(PL) in serum were remarkably higher in the hyperglycemic group(group BSW) and STZ(I.P.)+chitosan oligosaccharide supplementation group(group ECW) than those in the control group(group BW, basal diet+water). However the concentrations of blood glucose, total cholesterol, atherosclerotic index, LDL, LDL-cholesterol, tree cholesterol, cholesteryl ester ratio, TG and PL in serum were lower in the ECW group than in the BSW group, whereas the ratio of HDL-cholesterol concentration to total cholesterol and HDL-cholesterol concentration in the ECW group were higher than in the BSW group. The activities of alkaline phosphatase(ALP) and aminotransferase(AST, ALT) in serum were lower in the ECW group than in the hyperglycemic BSW group. The results shown above suggested that chitosan oligosaccharide supplementation effectively improves blood glucose, lipid composition and enzyme activities in the sera of STZ-induced hyperglycemic rats.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.61-70
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• 1999

This study is concerned with assessment of diethylnitrosamine(DEN) induced liver cell carcinogenesis by measurement of changes preceding the development of neoplasms. Therefore, it was undertaken to investigate the changes of liver-specific enzyme activities in rats (Sprague-Dawley) by ad libitum feeding of DEN. And also, as another objective index in urine, the level of urinary biopterin was measured by high performance liquid chromatography(HPLC) method. The results were as follows ; 1. Minor behavioral change, brittleness of hair and decreased amount of water and diet intake were observed in rats 7 weeks after DEN administration. 2. The body and liver weights were significantly(p<0.05) decreased in rats 11 weeks after DEN administration. 3. The ratio of liver weight to body weight was rather stable and not significantly decreased in the all treatment groups. 4. The liver specific enzyme activities(AST, ALT,$\gamma$-GTP) were significantly(p<0.05) increased in all treatment groups compared to control group. 5. Compared to normal level, urine biopterin level was significantly (p<0.05) increased in all treatment groups(p<0.05). In conclusion, this result confirmed that the DEN was one of the potent hepatocarcinogens. In experimental model of rats exposed to DEN, the results indicated that values of liver specific enzyme activities(AST, ALT, $\gamma$-GTP) and urine biopterin level could be useful complementary tumor indices.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.233-240
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• 1996

In order to study effects of Korean ginseng (Panax ginseng C.A. Meyer) saponin fraction on polyamine metabolism in rat organs, Korean ginseng saponin fraction was administrated to rats for 1, 2, 3, 4, 6 and 12 months and brain, liver, prostate, spleen and testis were removed from these rats. Two enzyme activities were measured from those organs; ornithine decarboxylase (ODC), which is a regulatory enzyme of putrescence biosynthesis and S-adenosylmethionine decarboxylase (SAMDC), which is also a regulatory enzyme of spermidine and spermine biosynthesis. The amounts of polyamine were also determined. As for prostate and testis organs, Korean ginseng saponin fraction was innocuous for ODC and SAMDC activities from rats fed for 1 and 2 months. However, after 3 months, the stimulatory effect on the activities of two enzyme gradually increased in test groups and reached its maximum in 12 months. The contents of spermidine and spermlne of test groups in prostate and testis were also much higher than those of control groups. Another stimulatory effect on the activities of two enzymes was observed in liver and reached its maximum in 6 months. In the other organs such as brain and spleen, the enzymes were turned out to be not affected by feeding Korean ginseng saponin fraction. From the cumulative results, the stimulatory effect of Korean ginseng saponin fraction on polyamine metabolism was observed in prostate, testis and liver.

• The Korean Journal of Mycology
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• v.26 no.1 s.84
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• pp.119-126
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• 1998

Mitochondria were isolated from Lentinus edodes and properties of the mitochondrial NADH dehydrogenase were studied. Optimal pH, temperature, and thermal stability of the enzyme were estimated to be 7.6, $33^{\circ}C$, and stable for one hour at $50^{\circ}C$. The apparent $K_m$ for the NADH was 0.33 mM. This enzyme catalyzed to transfer electrons from NADH to ferricyanide, decylubiquinone, and 2,6-dichloro-phenol-indophenol. 0.5 mM antimycin A and 0.01 mM dibromothymoquinone strongly inhibited 87.8% and 76.5% of the enzyme activities. 0.01 mM oligomycin known as an inhibitor of ATPase also strongly inhibited 79.2% of activities. 0.5 mM 5,5'-dithiobis-(2-nitrobenzoic acid) and 1.0 mM N-ethylmaleimide known as a modifier of SH group inhibited 50.4% and 36.7% of activities. 1 mM ethyl 2,4-dihydroxy-6-methyl benzoate and 10 mM orcinol, which had been known as an antibiotics isolated from Umbilicaria vellea according to our previous work, stimulated 68.4% and 48.1% of the enzyme activities.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.64-71
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• 2020

A total of 262 bacterial strains were isolated from clay minerals, bentonite and zeolite, in Gyeongsangbukdo, Republic of Korea, and their hydrolytic enzyme activities were analyzed. Most of the isolated strains belonged to Micrococcales and Bacillales order. Of strains, 96 strains produced α-amylase activity, 42 strains showed cellulase activity, 111 strains had pectinase activity, and 70 strains showed protease activity. Among them, 177 isolates exhibited one or more of the hydrolytic enzyme activities and in particular Bacillus cereus MBLB1321, B. albus MBLB1326 and KIGAM017, B. mobilis MBLB1328, MBLB1329 and MBLB1330 showed all of the enzyme activities. These results demonstrate the diversity of functional Bacillus species in clay minerals as vital sources for the discovery of industrially valuable hydrolytic enzymes, which have a great commercial prospect in various bio-industrial applications.

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1157-1162
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• 2017

The goal of this study was to identify and characterize selected Trichoderma isolates by metabolic profiling and enzyme assay for evaluation of their potential as biocontrol agents against plant pathogens. Trichoderma isolates were obtained from the Rural Development Administration Genebank Information Center (Wanju, Republic of Korea). Eleven Trichoderma isolates were re-identified using ribosomal DNA internal transcribed spacer (ITS) regions. ITS sequence results showed new identification of Trichoderma isolates. In addition, metabolic profiling of the ethyl acetate extracts of the liquid cultures of five Trichoderma isolates that showed the best anti-Phytophthora activities was conducted using gas chromatography-mass spectrometry. Metabolic profiling revealed that Trichoderma isolates shared common metabolites with well-known antifungal activities. Enzyme assays indicated strong cell wall-degrading enzyme activities of Trichoderma isolates. Overall, our results indicated that the selected Trichoderma isolates have great potential for use as biocontrol agents against plant pathogens.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.417-420
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• 2002

A strong fibrin-specific fibrinolytic enzyme was produced from Bacillus subtilis KH-4 isolated from Deonjang, a Korean fermented soybean paste similar to Japanese miso. The addition of glucose as a carbon source resulted in the highest levels of caseinolytic and fibrinolytic activities. Likewise, the addition of yeast extract as the nitrogen source resulted in the highest caseinolytic and fibrinolytic activities (3473.2 unit and 47.4 munit, respectively), It was observed that out of all metal ion sources only calcium (chloride) enhanced caseinolytic and fibrinolytic activities, with increases of 4949.3 unit and 58.2 unit/mg, respectively. The optimal temperature for the production of the enzyme was found to be 4$0^{\circ}C$ in the optimal medium (glucose 20 g, yeast extract 5 g, CaCl$_2$l g, and NaCl 2 g). The maximum fibrinolytic activity was observed at the late stationary phase. B. subtilis KH-4 produced a fibrinolytic enzyme at 4$0^{\circ}C$, after 30 h growth, which increased up to 54 h and then remained constant. These results suggest that Deonjang has potential as a source of physiologically active anti-thromotic enzymes.

• YAKHAK HOEJI
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• v.49 no.1
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• pp.86-91
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• 2005

Flavonoids are class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including antiviral, antithrombotic, antiinflammatory, antihistaminic, antioxidant and free-radica 1 scavenging abilities. The antioxidant enzyme (AOE) system plays an important role in the defense against oxidative stress insults. To determine whether flavonoid, myricetin can exert antioxidative effects not only directly by modulating the AOE system but also scavenging free radical, we investigated the influence of the flavonoid myricetin on cell viability, different antioxidant enzyme activities, ROS level and the expression of different antioxidant emzyme in B16F10 murine melanoma cells. Myricetin in a concentration range from 6.25 to $50\;{\mu}M$ decreased superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme activities, but catalase (CAT) activity was increased. In the myricetin-treated group, ROS levels were decreased dose-dependently. Antioxidant enzyme expression was measured by RT-PCR. Myricetin treatment of B16F10 cells increased catalase expression. Expression levels of copper zinc superoxide dismutase (CuZn SOD) were not affected by exposure of myricetin. Manganese superoxide dismutase (Mn SOD) and GPx expression levels decreased slightly after myricetin treatment. In conclusion, the antioxidant capacity of myricetin was due to CAT and free-radical scavenging.