• Korean Journal of Microbiology
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• v.35 no.4
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• pp.315-321
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• 1999

This study has been performed to deveope a yeast strain having high ${\alpha}$-amylase production ability using nuclear transfer method. Hybrids formed between the strains of Saccharomyces fiburigera KCTC 7393 and Saccharomyces cerevisiae KCTC 7049 (tyr-, ura-)were obtained by nuclear transfer technique. Nuclei isolated from the wild type S. fiburigera strain were transfered into auxotrophic mutants S. cerevisiae and selected the hybrids showing an increased starch degrading capability were selected (MN-16). This transformant grew best and produced maximal ${\alpha}$-amylase activity on the medium containing 2% (V/V) soluble starch. ${\alpha}$-Amylase from MN-16 was purified electrophoretically homogenety and its properties were investigated. The enzyme was purified about 10.6 fold with an overall yield 9.7% from the culture medium by ammonium sulfate fractionation. DEAE-Sephacel column chromatography, and Sephacryl S-200 column chromatography. The purified enzyme showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight of the ${\alpha}$-amylase was estimated to be 53,000 daltons by SDS-PAGE and by gel permeation chromatography on Sephacryl S-200. The purified enzyme showed the maximum activity at pH 5.5 and 40${\circ}C$. The km value for soluble starch was 2.5㎎/㎖. The enzyme activity increased in the presence of $Ca^{2+}, Co^{2+}, EDTA, Mg^{2+}, Mn^{2+}, Zn^{2+}$, but inhibited by $Cu^{2+}, Fe^{2+}$, and $Ni^{2+}$

• Korean Journal of Environmental Agriculture
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• v.16 no.3
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• pp.245-248
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• 1997

The study was carried out to elucidate the changes of ${\alpha}-amylase$ activity and free proline content for zinc toxicity in two rice cultivars(Ilpumbyeo and Namchunbyeo) during germination and early growth stages. Plant height in all kinetin treatments was promoted but zinc 120ppm treatment was decreased. Soaking treatment of kinetin $10^{-3}M$ increased germination rate of both cultivars, Ilpumbyeo and Namchunbyeo by 95% and 96% as compared with zinc 120ppm. Chlorophyll content of Ilpumbyeo was higher than that of Namchunbyeo. Activity of ${\alpha}-amylase$ in kinetin $10^{-3}M$ of both rice cultivars was most highest in the 3days after treatment of zinc 120ppm. Free proline content in all rice cultivars of zinc 120ppm treatment was sharply increased at the 3days after treatment of zinc 120ppm. As a result, the effects of kinetin treatment were recognized to promote the plant height and germination rate under zinc toxicity(120ppm) during rice seed germination and early growth stages.

• Journal of Aquaculture
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• v.21 no.3
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• pp.190-195
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• 2008

We investigated the changes in growth, digestive enzymes activities, nucleic acids contents and RNA/DNA ratio of flounder Paralichthys olivaceus larvae (C for Paracyclopina nana, A for Artemia, and M for Mix of C and A) for 14 to 28 DAH. Body length of flounder larvae showed the best in the C trial at 28 DAH. The change of nucleic acids contents showed faster in C and M trials than A trial. And RNA/DNA ratio showed the significantly faster changes in C trial than A trial. High metamorphosis rates were also observed in C and M trial. $\alpha$-amylase activities increased gradually up to 28 DAH in all trials. Total alkaline protease (TAP) activities of A trial showed the highest value to 9 mU/larvae at 26 DAH. But others trials showed lower to $5{\sim}6$ mU/larva than A trial. TAP:$\alpha$-amylase activity ratio did not significantly changed to $0.025{\sim}0.053$ in A trial during the experiments. But, C and M trials tended to gradually decrease from $0.078{\sim}0.083$ (initial) to $0.013{\sim}0.018$ (final). Therefore, it shown the ratio gradually decreased of TAP:$\alpha$-amylase activity, stability of TAP activity, and rapid change of nucleic acids in trials grown positively. Thus, because P. nana could continuously supply the optimal nutrients for flounder larvae, we suggested the supplement of the copepod to an efficient feed of the flounder larvae.

• Korean Journal of Microbiology
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• v.40 no.3
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• pp.230-231
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• 2004

The mycelia of Sparassis crispa DSMZ 5201 were cultivated at $24^{\circ}C$ for 15 days in yeast-malt extract-glucose broth (pH 4.0) and the filtrate was used as crude enzyme solution to determined the extracellular enzyme activity. The specific activity of $\alpha$-amylase was 44.27 unit/protein. The specific activities of protease, CMCase, $\beta$-glucosidase, chitinase, exo-$\beta$-l,4-glucanase were relatively high. However, a very little activity of xylanase was found.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.378-383
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• 2005

This study was conducted in order to exam­ine relationships between the viviparous germination ability and the antioxidative system in rice seeds and seedlings. Enzyme activities was compared among the four varieties with different viviparous germination ability from the early or mid-late maturity group. $\alpha$-Amylase activities correlated with the viviparous germination rate (VGRs) and $\alpha$-amylase activity in seeds of 40 days after heading (DAH) was highest in Dongjinbyeo among mid­late maturing varieties (MLMVs) and in Daeseongbyeo among EMVs. $\alpha$-Amylase activity in dry mature seeds was also higher in varieties with higher VGR. Glucose contents in viviparously germinating seeds and mature dry, seeds were higher in varieties with higher VGRs. Cat-alase activities did not correlate with the VGRs in both maturity groups. However, peroxidase activities in viviparously germinating seeds were higher in varieties with higher VGRs.

• Microbiology and Biotechnology Letters
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• v.9 no.3
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• pp.145-152
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• 1981

Microorganisms from the waste water of starch industry, were isolated and a strain, Y-124, possessing a powerful enzymic activity was selected and identified as a member of the genus Bacillus. The ideal cultural condition for the formation of $\alpha$-amylase form Bacillus Y-124 and its preservation was investigated in connection with the biotechnological and industrial approach to the bulk enzyme production. High yield of $\alpha$-amylase was observed in medium containing casein as well as calcium pantothenate in this work. Calcium ions were found to have an effect in forming this particular enzyme. Ammonium phosphate dibasic was an important inorganic nitrogen source for the formation of $\alpha$-amylase. And preservation of this enzyme was greatly affected by calcium or sodium salts. The addition of calcium carbonate or sodium sulfate presented the most effective result for the prevention of its denaturation to various factors. The above data was obtained with crude enzyme preparation.

• Journal of Mushroom
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• v.8 no.3
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• pp.102-108
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• 2010

In this study, growth rates and enzyme activities of mushroom mycelium were investigated in each cereals. Cultivation on hulled barley resulted in slightly faster mycelial growth as compared to other substrates. Enzyme activities were measured in different periods. In result, ${\alpha}$-amylase activity was higher in Pleurotus ostreatus and Phellinus linteus cultured cereals, whereas ${\beta}$-amylase activity was higher in Pleurotus ostreatus and Fomitella fraxinea cultured. Protease level did not affect kinds of cereal except Phellinus linteus. The color values lightness decrease by Basidiomycetes cultivation and redness and yellowness increased.

• KSBB Journal
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• v.14 no.6
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• pp.713-717
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• 1999

We have isolated a dextranase and amylase constitutive and hyper-producing mutant, Lipomyces starkeyi JLC26, from Lipomyces starkeyi ATCC74054 after mutation using UV irradiation. After partial purification of dextranase and amylase (together DXAMase;both activities were always co-purified) by ammonium sulfate precipitation, CM-Sepharose column chromatography, the specific activities of amylase and dextranase were 5367 and 3045 unit/mg, respectively. The pH effects for activity and stabiligy of both enzymes were similar to each other: Optimum pH and temperature for activity sere at 5.5 and 37$^{\circ}C$ and optimum ranges for stability were at pH 2.5-5.5 and 4-55$^{\circ}C$, respectively. The reaction end products of dextranase and amylase activities were found to the typical for those of endo-dextranase and endo-amylase. When the carbohydrase and maltotriose were reacted, glucose, maltose, isomaltose, maltotriose, panose and ${\alpha}(1{\rightarrow}6)$glucosylmaltotriose were produced by disproportionation reaction.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.181-186
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• 2016

This study was designed to investigate the inhibitory effect of Gynura procumbens extract against carbohydrate digesting enzymes and its ability to ameliorate postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. G. procumbens extract showed prominent ${\alpha}$-glucosidase and ${\alpha}$-amylase inhibitory effects. The half-maximal inhibitory concentration ($IC_{50}$) of G. procumbens extract against ${\alpha}$-glucosidase and ${\alpha}$-amylase was $0.092{\pm}0.018$ and $0.084{\pm}0.027mg/mL$, respectively, suggesting that the ${\alpha}$-amylase inhibition activity of the G. procumbens extract was more effective than that of the positive control, acarbose ($IC_{50}=0.164mg/mL$). The increase in postprandial blood glucose levels was more significantly alleviated in the G. procumbens extract group than in the control group of STZ-induced diabetic mice. Moreover, the area under the curve significantly decreased with G. procumbens extract administration in STZ-induced diabetic mice. These results suggest that G. procumbens extract may help alleviate postprandial hyperglycemia by inhibiting carbohydrate digesting enzymes.

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1390-1401
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• 2023

In this study, a 12-week feeding experiment was conducted to characterize the effects of exogenous α-amylase on the growth, feed utilization, digestibility, plasma α-amylase activity, feed degradation rate, and fecal particle size of olive flounder (Paralichthys olivaceus). Diet was supplemented with 0 (AA₀; control), 100 (AA₁₀₀), 200 (AA₂₀₀), or 400 (AA₄₀₀) mg/kg of α-amylase, respectively. Fish (273.1 ± 2.3 g) were stocked into 12 tanks (25 fish/1,000-L tank) and 3 tanks were randomly selected for each diet group. As a result, α-amylase was found to have no significant effects (p ≥ 0.05) on the growth, feed utilization parameters, and whole-body proximate compositions. α-Amylase-treated fish exhibited only a significant increase in the apparent digestibility coefficient of carbohydrates compared to the controls. In addition, in vitro analyses revealed that α-amylase dose-dependently increased (p < 0.05) the feed degradation rate, while photographs of the intestinal content after 2, 4, and 8 h of feeding demonstrated an improved degradation rate in the α-amylase-treated groups. Plasma α-amylase content was higher in the AA₂₀₀ and AA₄₀₀ groups, whereas the control group produced significantly larger-sized fecal particles (90% size class) than these two groups. In the intestine, no changes were observed in the expression levels of the immune-related TNF-α, IL-1β, IL-2, immunoglobulin-M, HSP-70, lysozyme, and amylase alpha-2A. However, growth-related genes IGF-1, IGF-2, TGF-β3, and growth hormone genes were upregulated in muscle tissues. Collectively, exogenous α-amylase has positive roles in the modulation of the digestibility coefficient, blood α-amylase concentration, growth-related gene expression, and diet degradation for improved digestion in olive flounder.