• Animal Bioscience
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• v.36 no.10
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• pp.1488-1498
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• 2023

Objective: α_S1-Casein is more closely associated with milk allergic reaction than other milk protein components. microRNA (miRNA) is a class of small non-coding RNAs that modulate multiple biological progresses by the target gene. However, the post-transcriptional regulation of α_S1-casein expression by miRNA in ruminants remains unclear. This study aims to explore the regulatory roles of miR-380-3p on α_S1-casein synthesis in goat mammary epithelial cells (GMEC). Methods: α_S1-Casein gene and miR-380-3p expression was measured in dairy goat mammary gland by quantitative real-time polymerase chain reaction (qRT-PCR). miR-380-3p overexpression and knockdown were performed by miR-380-3p mimic or inhibitor in GMEC. The effect of miR-380-3p on α_S1-casein synthesis was detected by qRT-PCR, western blot, luciferase and chromatin immunoprecipitation assays in GMEC. Results: Compared with middle-lactation period, α_S1-casein gene expression is increased, while miR-380-3p expression is decreased during peak-lactation of dairy goats. miR-380-3p reduces α_S1-casein abundance by targeting the 3'-untranslated region (3'UTR) of α_S1-casein mRNA in GMEC. miR-380-3p enhances β-casein expression and signal transducer and activator of transcription 5a (STAT5a) activity. Moreover, miR-380-3p promotes β-casein abundance through target gene α_S1-casein, and activates β-casein transcription by enhancing the binding of STAT5 to β-casein gene promoter region. Conclusion: miR-380-3p decreases α_S1-casein expression and increases β-casein expression by targeting α_S1-casein in GMEC, which supplies a novel strategy for reducing milk allergic potential and building up milk quality in ruminants.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.238-243
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• 2005

This study was carried out to understand hyrolytic characteristics of $\beta-casein$ by enzyme in goat milk and to measure the inhibition effect of the ACE of the hydrolysate. In order to conduct the experiment, $\beta-casein$ of goat milk was separated using Mono S HR 5/5, a cation exchange column. The separated $\beta-casein$ was treated with trypsin of animal hydrolysis enzymes, in an effort to verify the characteristics of hydrolysis. The inhibition activity of ACE was measured and the results are as follows. By analyzing the hydrolysate separated from the trypsin-processed $\beta-casein$ of goat milk, the inhibition effect of the ACE was measured trypsin-hydrolyzed $\beta-casein$ demonstrated a $25.36\pm0.79\%$ of inhibition effect and the $IC_{50}$ of the hydrolysate from the trypsin-processed $\beta-casein$ reached $308.7\pm2.77({\mu}g/mL)$.

• Journal of Dairy Science and Biotechnology
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• v.18 no.1
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• pp.1-8
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• 2000

This experiment was carried out to study fractionation and physicochemical characteristics of caprine casein. Acid caseins obtained from caprine colostral and normal milk were analyzed by chymosin treatment and fractionated by DEAE-cellulose column chromatography with linear gradient and electrophoresis. Protein, fat and lactose of caprine normal milk were 2.70${\pm}$0.27%, 3.82${\pm}$0.51%, and 4.10${\pm}$0.29%, respectively. More non-protein nitrogen(NPN) was released by chymosin treatment from caprine colostral casein than normal casein. The electrophoretic pattern of caprine casein was not similar to that of bovine casein, Caprine normal casein was fractionated by DEAE-cellulose column chromatography with a 0.08${\sim}$0.18 M NaCl linear gradient into 5 pes with the proportion of 5.27%, 26.07%, 25.97%, 30.40% and 12.29%, respectively. In order to identify the pure fraction, the chymosin-treated caprine normal casein was fractionated by DEAE-cellulosecolumn chromatography with a 0.08${\sim}$0.18 M NaCl linear gradient into 6 peaks with the proportion of 17.06%, 9.10%, 17.85%, 20.11%, 27.03% and 8.85%, respectively.

• Journal of Nutrition and Health
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• v.26 no.3
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• pp.231-247
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• 1993

This study was designed to confirm the effect of dietary protein level and oral administration of tryptophan on brain serotonin metabolism. Two animal experiments were conducted. The objectives and results of research were as follows : In the first experiment, it was investigated whether administration of reserpine to Sprague-Dawley rats fed 6% or 20% casein diet induced decrease in serum tryptophan and large neutral amino acid(LNAA) concentrations, tryptophan/LNAA concentration ratio, brain tryptophan, serotonin and 5-hydroxyindoleacetic acid(5-HIAA) contents. Brain serotonin content of 6% casein diet group was lower than those of 20% casein diet group. Both 6% and 20% casein diet groups administered with reserpine to induce the analogous depression, showed the notable decrease in brain serotonin content when they were compared with 20% casein diet group not administered with reserpine. Serum tryptophan/LNAA ration and brain 5-HIAA content showed a tendency similar to the change of serotonin content, but the mean difference among all groups was not significant. From these results, it could be said that when the dietary protein level was low, brain serotonin content was decrease. The second experimnt was to see the change in serum tryptophan concentration and tryptophan/LNAA ratio and brain tryptophan, serotonin and 5-HIAA content when tryptophan was administered orally to the animals treated with reserpine. Serum tryptophan concentration tended to increase in both reserpine-treated 6% and 20% casein diet groups administered with tryptophan, especially in the 6% casein diet group. Serum tryptophan/LNAA concentration ratio tended to incrase in reserpine-tteated 6% casein diet group, while decrease in reserpine-treated 20% casein diet group. Brain tryptophan content was increased in both reserpine-treated 6% and 20% casein diet groups. However, brain serotonin content of reserpine-treated 6% casein diet group showed a tendency to decrease, while that of reserpine-treated 20% casein group increase. Consequently, the effect of tryptophan administration on increase of brain tryptophan and serotonin content in animals treated with reserpine was far more excellent in 20% casein diet groups. It was concluded that dietary protein intake and tryptophan administration increase brain serotonin level. Accordingly, it was possible to confirm that brain function, particularly in aspect of behavior related to the serotonin, was changed with manipulation of dietary composition.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.196-200
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• 1999

A recombinant human $\alpha_{s1}$-casein was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Three different leader sequences derived from the mating factor $\alpha$l (MF$\alpha$l), inulinase, and human $\alpha_{s1}$-casein were used to direct the secretion of human $\alpha_{s1}$-casein into the extracellular medium. Among the three leader sequences tested, the native leader sequence of human $\alpha_{s1}$-casein was found to be the most efficient in the secretory expression of human $\alpha_{s1}$-casein, which implies that the native leader sequence of human $\alpha_{s1}$-casein might be used very efficiently for the secretory production of other heterologous proteins in yeast. The recombinant human $\alpha_{s1}$-casein was proteolytically cleaved as the culture proceeded. Therefore, an attempt was made to produce human $\alpha_{s1}$-casein using a S. cerevisiae mutant in which the YAP3 gene encoding yeast aspartic protease 3 (YAP3) was disrupted. After 72 h of culture, most of the human $\alpha_{s1}$-casein secreted by the wild type was cleaved, whereas more than 70% of the human $\alpha_{s1}$-casein secreted by yap3-disruptant remained intact. The results suggest that YAP3 might be involved in the internal cleavage of human $\alpha_{s1}$-casein expressed in yeast

• Journal of Nutrition and Health
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• v.3 no.2
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• pp.81-85
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• 1970

These experiments were designed to study the influence of protein undernutrition during lactation period(3 wks) or after-weaning period(8 wks) on growth of organs, and on brain and liver composition of the experimental rats. The following experimental groups were studied. Group No. Rats Lactation(3 wks) (Diet of mother rat) After-weaning period(8wks) Rehabilitation Period(17wks) I 8 25% Casein diet 25% Casein diet 25% Casein diet II 8 12% Casein diet 25% Casein diet 25% Casein diet III 8 25% Casein diet 5% Casein diet 25% Casein diet IV 8 12% Casein diet 5% Casein diet 25% Casein diet After the perriod of rehabilitation(17 wks) with 25% casein diet, the following results were obtained. 1. Most of the organs except the spleen could not catch up with the normal group in their weights for the group of protein undernutrition during lactation(3 wks), even after 17 weeks of rehabilitation. For the group of protein undernutrition during after-weaning period(8 wks) brain, lung, heart, spleen and pancreas could catch up with the normal group after rehabilitation. According to this result it is assumed that the growth of brain, lung, heart and pancreas might be developed mostly during lactation and that the growth of liver and kidney might be developed after-weaning period continuously. 2. For the groups of protein underuntrition during lactation period or after-weaning period the amounts of total lipid, cholesterol and phospholipid of brain were lower than those of normal group. Especially, cholesterol level was significantly lower than normal group. And there was also a significant difference in the phospholipid level of the after-weaning(8 wks) deprivation group. 3. The groups of protein undernutrition during lactation or after-weaning period(8 wks) showed lower level of liver nitrogen and higher level of liver fat. Especially, protein undernutriton during lactation gave a greater influence on the lever of liver fat.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1976.04a
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• pp.182.5-183
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• 1976

Mucor-rennin(MR)과 Calf-rennin(CR)을 k-Ca-sein에 반응시켜 para-k-Casein과 macropeptide를 분리하였다. 분리한 Para-k-casein과 macropeptide에 대한 전기영동, 원소분석을 행하였다. MR로 분해하여 얻은 para-k-casein의 N-미단은 없고, Cpase를 반응시켰을 때 Paper chromatography 상에서 Phe, Leu를 확인할 수 있었다. Macropeptide의 N미단은 Edman법에 의하여 Met으로 확인되였다. 이 결과로부터 CR은 para-k-casein의 C미단 Phe과 macropeptide의 N미단 Met간의 결합 즉 Phe-Met결합을 가수분해한다고 생각할 수 있다. 그리고 CR을 k-casein에 작용시켜 얻은 기질특이성은 MR의 결과와 같았다.

• Journal of Nutrition and Health
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• v.16 no.4
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• pp.273-280
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• 1983

The effect of alteration of light-darkness cycle on the protein metabolism was studied in the rat. The light-darkness cycle was altered either every 3 or 9 days, and animals consumed diets containing 8 or 25% casein. The results were summarized as follows : 1) Food consumptions and body weight gains of the 25% casein groups were higher than those of the 8% casein groups, and, among the animals consumed 25% casein diet, the light-darkness cycle altered group had lower food consumption and body weight gain than the unaltered group. 2) Weights of liver and adrenal gland per l00g body weight were not different with the dietary protein levels, but, at the end of experimental period, the 8% casein diet group of which light-darkness cycle altered every 9 days had the smallest liver weight and the largest adrenal gland weight. 3) Liver nitrogen and plasma protein concentrations of the 25% casein groups were slightly higher than those of the 8% casein groups. 4) Percentages of nitrogen retention of the 25% casein groups at period III were slightly lower in the light-darknerr cycle altered animals than that of the unaltered group.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2006.05a
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• pp.269-271
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• 2006

Casein과 whey의 가수분해 물에 대한 항산화 능을 측정하기 위해 연구를 수행하였다. pH에 따른 Total antioxidant capacity(TAC)는 casein 및 whey 모두 pH 6.0 에서 보다 pH 7.4에서 더 높은 TAC 결과를 나타내었다. Casein이 whey보다 농도가 증가함에 따라 TAC 값이 증가하였으며 이는 배양시간이나 pH에 따른 TAC 측정에서와 같이 casein이 whey보다 더 높은 TAC 값을 나타내고 있으나, $2,000{\mu}g/mL$에서는 TAC 값이 감소하여 casein, whey 모두 유사한 TAC 값을 나타내었다. Trypsin에 의한 casein 및 whey의 가수분해는 반응 10분 이후부터는 NPN 량이 더 이상 증가하지 않았으며 casein보다 whey가 분해율이 낮았다. Trypsin처리한 casein과 whey의 TAC를 측정한 결과로서 trypsin 처리구가 무처리구에 비해 높은 TAC 결과를 나타내었다.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.778-786
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• 2017

In this study, analyzed the changes occurred after adding casein emulsions to water - dispersed polyurethane using polypropylene glycol (PPG). For this purpose, anionic water - dispersed polyurethane containing PPG, IPDI and DMPA and casein emulsion prepared by dissolving casein in distilled water using ammonia water were prepared. As a result of measuring the alkali resistance by using the prepared resin, there was no change in the physical properties. The tensile strength of the sample having a high casein content was measured to be $2.227kgf/mm^2$. Elongation was measured at 474% for samples containing less casein and The abrasion resistance was measured as 46.090 mg.loss of sample containing much casein as a result of the surface roughness measurement.