• Asian-Australasian Journal of Animal Sciences
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• 제17권10호
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• pp.1411-1416
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• 2004

The objective of this work was to isolate a microorganism, able to produce high lactate dehydrogenase (LDH) activity, for use as a microbial feed additive. The LDH is an important enzyme for lactate conversion in the rumen, thereby possibly overcoming lactic acidosis owing to sudden increases of cereal in the diets of ruminants. In the present study, various bacterial strains were screened from a variety of environments. Among the isolated microorganisms, strain FFy 111-1 isolated from a Korean traditional fermented vegetable food called Kimchi showed the highest enzyme activity, along with retaining strong enzyme activity even in rumen fluid in vitro. Based on morphological and biochemical characteristics as well as compositions of cellular fatty acids plus API analyses, this strain was identified as Lactobacillus sp. The optimum temperature and pH for growth were found to be 30$^{\circ}C$ and pH 6.5, respectively. A maximum cell growth of 2.2 at $A_{650}$ together with LDH activity of 2.08 U per mL was achieved after 24 h of incubation. Initial characterization of FFy 111-1 suggested that it could be a potential candidate for use as a direct-fed microbial in the ruminant animals.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.445-448
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• 2002

The Pseudomonas fluorescens KCTC 1767, a selected and identified as potential candidate for stereo-specific resolution of rac-ketoprofen ethyl ester, was systematically investigated in order to induce the high level expression and detailed characterization of the expressing enzyme esterase. We cloned the esterase gene from chromosomal DNA of Pseudomonas fluorescens KCTC 1767 by PCR with two synthetic primers that desinged for simple purification. The recombinant esterase from Pseudomonas fluorescens KCTC 1767 exibited a high conversion rate and enantioselectivity to the (S)-ketoprofen ethyl ester as expected. The enzyme was easily purified to homogeniety by using a metal chelating affinity chromatography as a protein with poly histidine taq, and thus obtained 0.6 mg of protein from a 100 mL culture broth in a single step. The purified enzyme was steadily stable at the pH range from 7.0 to 10. The activity was also retained to be about 70% after the preincubation at $40^{\circ}C$ but over $50^{\circ}C$ lost the activity completely. The molecular mass of the esterase was estimated to be about 43 kDa on SDS-PAGE, and an identical result was also shown in gel filteration chromatography. The specific activity was calculated 27 mM/mg-protein/min by using the rac-ketoprofen ethly ester as a substrate.

• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.340-345
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• 1999

A novel simultaneous saccharification and fermentation (SSF) process from the microcrystalline cellulose to ethanol was developed by using $\delta$-integrated recombinant cellulolytic Saccharomyces cerevisiae L2612$L2612\deltaGC$, which can utilize cellulose as carbon and energy sources. The optimum amount of enzymes needed for the efficient conversion of cellulose to ethanol at $30^{\circ}C$ was determined with commercial cellulolytic enzymes. By fed-batch cultivation, the heterologous cellulolytic enzymes were accumulated up to 42.67% of the total cellulase and 29% of the $\beta$-glucosidase needed for the efficient SSF process. When this $\delta$-integrated recombinant yeast was applied to the successive SSF step for ethanol production, 20.35 g/l of ethanol was produced after 12 h from 50 g/l of microcrystalline cellulose. By using this novel SSF process, a considerable amount of commercial enzymes was reduced.

• KSBB Journal
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• 제29권1호
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• pp.1-8
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• 2014

Tyrosinases catalyze the hydroxylation of monophenolic compounds and the conversion of o-diphenols to oquinones. The enzymes are mainly involved in the modification of tyrosine into L-3,4-dihydroxyphenyl-alanine (L-DOPA) and DOPA/DOPAquinone-drived intermolecular cross-linking, which play the key roles of pigmentation to the cells. It is ubiquitously distributed in microorganisms, plants, and animals all around the nature world. They are classified as copper- containing dioxygen activating enzymes; two copper ions are coordinated with six histidine residues in their active sites and they are distinguished as met-, deoxy-, and oxy-form depending on their oxidative states. Natural extraction and recombinant protein approaches have been tried to obtain practical amounts of the enzymes for industrial application. Tyrosinases have been widely applied to industrial and biomedical usages such as detoxification of waste water containing phenolic compounds, L-DOPA as a drug of Parkinson's disease, biomaterials preparation based on the cross-linking ability and biosensors for the detection of phenolic compounds. Therefore, this review reports the mechanism of tyrosinase, biochemical and structural features and potential applications in industrial field.

• Macromolecular Research
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• 제14권5호
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• pp.524-529
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• 2006

New, thermally robust, arylenevinylene conjugated polymers, including poly(9,9-dioctylfluorenyl-2,7-vinylene) [poly(FV)] and poly[2-(3'-dimethyldodecylsilylphenyl)-1,4-phenylenevinylene] [poly(m-SiPhPV)], were synthesized and used for the fabrication of efficient photovoltaic cells. Bulk heterojunction photovoltaic cells fabricated by blending one of the polymers, [poly(FV)], [poly(m-SiPhPV)], and poly(FV-co-m-SiPhPV), with the fullerene derivative [6,6]-phenyl-$C_{61}$-butyric acid methyl ester (PCBM) were found to have a power conversion efficiency of up to 0.038%..

• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1291-1298
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• 2015

Five different polymer nanofibers, namely, polyaniline nanofiber (PANI), magnetically separable polyaniline nanofiber (PAMP), magnetically separable DEAE cellulose fiber (DEAE), magnetically separable CM cellulose fiber (CM), and polystyrene nanofiber (PSNF), have been used for the immobilization of lactase (E.C. 3.2.1.23). Except for CM and PSNF, three polymers showed great properties. The catalytic activities (k_cat) of the free, PANI, PAMP, and magnetic DEAE-cellulose were determined to be 4.0, 2.05, 0.59, and 0.042 mM/min·mg protein, respectively. The lactase immobilized on DEAE, PANI, and PAMP showed improved stability and recyclability. PANI- and PAMP-lactase showed only a 0-3% decrease in activity after 3 months of vigorous shaking conditions (200 rpm) and at room temperature (25℃). PANI-, PAMP-, and DEAE-lactase showed a high percentage of conversion (100%, 47%, and 12%) after a 1 h lactose hydrolysis reaction. The residual activities of PANI-, PAMP-, and DEAE-lactase after 10 times of recycling were 98%, 96%, and 97%, respectively.

• 한국가금학회지
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• 제42권3호
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• pp.197-204
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• 2015

본 연구는 천연항산화 생리활성 소재로서 가시오갈피를 육계에게 0(CON), 0.5(AS1) 및 1.0%(AS2) 수준으로 급여하여 생산성, 면역장기 무게, 혈액 생화학적 성상 및 친염증 사이토카인 mRNA 발현에 미치는 영향을 조사하였다. 전 사육기간에서 가시오갈피 급여에 따른 체중, 증체 및 사료섭취량은 유의적 차이를 보이지 않았으나, AS2구에서 사료요구율이 유의적으로(p<0.05) 저하되었다. 면역장기 무게를 관찰한 결과, 간, 비장, F-낭 및 흉선 무게는 가시오갈피 급여에 따른 영향이 없었다. 혈액 생화학적 성분에서 albumin, total protein, cholesterol, AST, ALT 등과 같은 대부분의 성분은 대조구와 처리구간 차이는 없었다. 그러나 triglycerides는 대조구에 비해 AS2구에서 현저히(p<0.05) 높았고, glucose 수준은 대조구에 비해 가시오갈피 급여구에서 현저히(p<0.05) 증가되었다. 친염증 사이토카인 mRNA 발현을 조사한 결과, 가시오갈피 급여에 따라 백혈구의 IFN-${\gamma}$ mRNA 발현이 현저히(p<0.05) 감소되었으며, IL1-${\beta}$, IL-6, TNF-${\alpha}$, iNOS 등은 유의적 차이는 없었지만, 감소되는 경향이 있었다. 비장에서 친염증 사이토카인 발현은 유의적 차이가 없었다. 간 조직에서는 0.5% 가시오갈피 급여에 따라 iNOS mRNA 발현이 유의적으로(p<0.05) 감소하였지만, 다른 친염증 사이토카인 발현은 유의적 차이는 없었다. 따라서 육계 생산성 및 친염증 사이토카인 발현에 미치는 영향 등을 고려할 경우, 0.5% 수준의 가시오갈피 급여가 가장 바람직한 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1650-1655
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• 2003

Crossbred gilts (n=54) of about $26.38{\pm}0.85kg$ body weight and 25 weeks of age were randomly divided into 18 groups of 3 animals each. Three dietary treatments viz., $T_1$, $T_2$ and $T_3$ were formulated. The treatment $T_1$ containing maize grain (35%) and wheat bran (47%) along with soybean meal and fish meals served as control diet. Rice bran (RB) was selected as a single source of fat (13.02%) and fibre (17.12%), which was gradually increased in diets $T_2$ (41%) and $T_3$ (82%) replacing maize grain and wheat bran of $T_1$ at 50% and 100% in the diets $T_2$ and $T_3$, respectively. The fat and fibre levels of the diets were thus 3.46 and 5.24, 9.31and 9.69 and 11.61and 13.26% in $T_1$, $T_2$ and $T_3$, respectively. All the diets, however, contained almost similar concentration of CP (18.35${\pm}0.29%$). Each dietary treatment was offered to six replicated groups of 3 piglets in following completely randomized design and feeding was continued for 112 days during the growing phase. Growth, feed utilization, reproductive performance, nutrient utilization and different blood biochemical parameters were studied. Growth rate, feed intake and feed conversion were lower (p<0.01) in $T_3$ in comparison to $T_1$ or $T_2$. Digestibility of all the nutrients except EE was reduced significantly (p<0.01) in $T_3$. Serum glucose level decreased (p<0.01), whereas the urea and cholesterol concentration in the blood increased (p<0.01) in $T_3$. The duration of estrus of pigs fed diet containing 82% RB ($T_3$) was highly variable within the group, but all the groups showed statistically similar duration of estrous. Feed cost per unit gain was found to be comparable between control ($T_1$) and $T_2$ group. The results indicated that RB can be included up to 41% in swine diets replacing 50% of maize and wheat bran. Higher concentrations of ether extract and fibre beyond 9.31 and 9.69% in diet had detrimental effect on growth, nutrient utilization and reproductive performance.

• 생명과학회지
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• 제28권3호
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• pp.351-356
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• 2018

L-세린 탈수화효소(LSD)는 L-serine을 피루브산과 암모니아로 전환하는 반응을 촉매하는 iron-sulfur 함유 효소이다. 세균성 아미노산 탈수화 효소 중에서, L-serine에 대한 이들 특정 효소만이 촉매 부위에서 iron-sulfur cluster를 이용하는 것으로 보고되고 있다. 또한, 세균성 LSD는 구조적 특성과 도메인의 배열에 따라 네 가지 유형으로 분류된다. 현재까지, 이 효소들은 소수의 균주로부터 얻어진 LSD 효소에 대해서만 연구되었지만, 다양한 세균성 LSD의 촉매 메커니즘을 이해하기 위해서는 더 많은 자세한 조사가 요구된다. 본 연구에서, Mycobacterium tuberculosis H37Rv로부터 유래된 유형 II LSD (MtLSD) 단백질을 효소 동력학적 방법을 이용하여 생화학적 및 촉매적 특성을 규명하기 위해 발현 및 정제되었다. MtLSD에 대한 L-serine의 포화 곡선은 알로스테릭 협동성(allosteric cooperativity)을 나타내는 전형적인 S자형(sigmoid)의 특성을 보였다. 이때의 $K_m$과 $k_{cat}$ 값은 각각 $59.35{\pm}1.23mM$과 $18.12{\pm}0.20s^{-1}$로 계산되었다. 또한, 고정된 L-serine 농도 하에서 D-serine의 농도 대비 초속도에 대한 그래프는 비선형 쌍곡선 감쇠 형태를 보였고, $k_{cat}$ 값의 변화 없이 $30.46{\pm}5.93mM$의 겉보기 $K_i$ 값으로 D-serine에 대한 경쟁적 억제(competitive inhibition)를 나타내었다. 이들 연구는 MtLSD의 촉매 특성 및 기질 특이성에 관한 통찰력 있는 생화학적 정보를 제공한다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.732-741
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• 2020

Objective: The study was conducted to investigate the effects of Broussonetia papyrifera L. (B. papyrifera) silage on growth performance, serum biochemical parameters, meat quality, and meat amino acids and fatty acids compositions in beef cattle. Methods: Sixty-four male Angus beef cattle were assigned to 4 groups with 4 pens in each group and 4 beef cattle in each pen, and fed with the total mixed ration supplemented with 0%, 5%, 10%, or 15% B. papyrifera silage for 100 days (control group, 5% group, 10% group and 15% group) separately. Results: Beef cattle had significantly higher final body weight (BW) in 15% group, higher average daily gain (ADG) and dry matter intake (DMI) in 5% group, 10% group and 15% group, and higher feed conversion ratio (FCR) in 10% group and 15% group. Significantly higher blood superoxide dismutase (SOD) concentration was noted in 15% group, higher blood total antioxidant capacity (TAC) in 10% group and 15% group, lower 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) in 15% group. Meat had lower pH in 15% group, higher Commission International DeI'Eclairage (CIE) L^⋆ in 5% group, 10% group, and 15% group, and lower drip loss in 15% group. Greater concentration of meat polyunsaturated fatty acids (PUFA) was observed in 10% group and 15% group, and docosahexaenoic acid (DHA) in 15% group. Conclusion: Diet with 15% B. papyrifera silage could improve performance and increase final BW, ADG, DMI, and FCR, enhance the antioxidant functions by decreasing blood 8-OHdG and MDA and increasing blood SOD and TAC, improve the meat quality by lowing pH and drip loss and increasing CIE L^⋆, increase the meat PUFA and DHA concentration. Polyphenols and flavonoids might be the main components responsible for the antioxidant activity and anti-biohydrogenation in the B. papyrifera silage. And B. papyrifera silage could be used as a new feedstuff in beef cattle nutrition.