• Journal of Animal Science and Technology
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• 제44권6호
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• pp.801-808
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• 2002

상업적 단백질 분해 효소에 0.02% $CaCl_2$를 첨가하여 응유 활성화를 시킨 탈지유에 대한 분해 작용의 결과를 요약하면 다음과 같다. 다양한 효소별 가수분해 시간에 따른 가수분해도는 미생물 유래 효소와 trypsin은 pepsin과 papain W-40보다 높은 분해도를 나타냈다. 12% TCA 용액에 가용성인 NPN의 양은 trypsin이 가장 높은 분해도를 나타내었고 rennet과 pepsin이 가장 낮은 분해도를 보였다. 전기영동에 있어서 trypsin과 protease S는 $\alpha$- lactalbumin을 분해하였고 papain w-40은 $\beta$- lactoglobulin을 미약하게 분해하였으며 neutrase 1.5는 90분 이후부터 $\alpha$-lactalbumin과 $\beta$-lactoglobulin을 분해하였다. Rennet과 비교한 전기영동상에서는 rennet에 의해 분해 되지 않은 ${\alpha}_s$- casein과 $\beta$-casein을 trypsin과 protease S가 다량 분해하였고 $\kappa$-casein은 rennet에 비해 papain W-40이 상당 수준의 분해상을 나타내었다. 이상의 결과 가수분해도 및 NPN 양은 trypsin, neutrase 1.5 및 protease S가 다른 효소에 비해 높게 나타났으며, 전기영동상에서는 pepsin과 neutrase 1.5가 rennet과 유사한 경향을 나타내었다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권3호
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• pp.414-421
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• 2014

This study was conducted to determine the effects of saturated long-chain fatty acids (LCFA) on cell proliferation and triacylglycerol (TAG) content, as well as mRNA expression of ${\alpha}s1$-casein (CSN1S1) and genes associated with lipid and protein synthesis in bovine mammary epithelial cells (BMECs). Primary cells were isolated from the mammary glands of Holstein dairy cows, and were passaged twice. Then cells were cultured with different levels of palmitate or stearate (0, 200, 300, 400, 500, and 600 ${\mu}M$) for 48 h and fetal bovine serum in the culture solution was replaced with fatty acid-free BSA (1 g/L). The results showed that cell proliferation tended to be increased quadratically with increasing addition of stearate. Treatments with palmitate or stearate induced an increase in TAG contents at 0 to 600 ${\mu}M$ in a concentration-dependent manner, and the addition of 600 ${\mu}M$ was less effective in improving TAG accumulation. The expression of acetyl-coenzyme A carboxylase alpha, fatty acid synthase and fatty acid-binding protein 3 was inhibited when palmitate or stearate were added in culture medium, whereas cluster of differentiation 36 and CSN1S1 mRNA abundance was increased in a concentration-dependent manner. The mRNA expressions of peroxisome proliferator-activated receptor gamma, mammalian target of rapamycin and signal transducer and activator of transcription 5 with palmitate or stearate had no significant differences relative to the control. These results implied that certain concentrations of saturated LCFA could stimulate cell proliferation and the accumulation of TAG, whereas a reduction may occur with the addition of an overdose of saturated LCFA. Saturated LCFA could up-regulate CSN1S1 mRNA abundance, but further studies are necessary to elucidate the mechanism for regulating milk fat and protein synthesis.

• 한국축산식품학회지
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• 제33권2호
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• pp.198-204
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• 2013

This study aimed to apply the Parallux system to detect (fluoro)quinone antibiotics residues in raw bovine milk. The immunogen enabled the generation of a specific antiserum with a titer of 1/40,000. The $Parallax^{TM}$ kit using the antibody displayed $IC_{50}$ value of 10 to 150 ppb for (fluoro)quinolone antibiotics. $Parallax^{TM}$ kit was also sensitive for the detection of incurred (fluoro)quinolone at Korean Maximum Residual Levels in raw bovine milk as the result of dose response test. Cross reactivities of the antibody with the common (fluoro)quinolones were determined to be norfloxacin, 100%; enrofloxacin, 100%; ciprofloxacin, 100%; danofloxacin, 100%; nalidixic acid, 40%. Lower detection limit (LOD) values of the $Parallax^{TM}$ kit in raw bovine milk were determined to be norfloxacin, 4 ppb; enrofloxacin, 5 ppb; danofloxacin, 5 ppb; ciprofloxacin, 5 ppb and nalidixic acid, 10 ppb. The $Parallax^{TM}$ kit was run 8 times with five different concentrations of norfloxacin to determine the coefficient of variation (CV, %) of intra-assay, which was between 2.7% and 11.8%. To confirm the precision among kit batches for the inter-assay, five different batch kits were tested with 2 different concentration of norfloxacin. The CVs of the inter assay were 4.2% at 50 ppb, and 7.2% at 10 ppb norfloxacin, respectively.

• 한국동물위생학회지
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• 제44권3호
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• pp.133-140
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• 2021

This study was aimed to investigate the prevalence and antimicrobial resistance of Pseudomonas spp. isolated from bovine mastitis milk samples. A total of 50 (4.9%) Pseudomonas spp. was isolated from 1,023 samples, those collected between 2018 and 2021, derived from 110 dairy farms. The prevalence of the identified species of Pseudomonas isolates was as follows; P. aeruginosa (70.0%), P. fluorescens (14.0%), P. putida (10.0%), P. fragi (4.0%), and P. chlororaphis (2.0%). Most of somatic cell counts in the quarter milk carrying Pseudomonas spp. were less than 3,000,000 cell/ml (90.0%). The isolates of Pseudomonas spp. showed high susceptibility to cefepime (98.0%), ciprofloxacin (98.0%), ceftazidime (96.0%), and colistin (96.0%). The rate of antibiotic resistance in the isolates was highest to ceftiofur (92.0%), followed by the resistance rate to chloramphenicol (86.0%) and trimethoprim/sulphamethoxazole (80.0%). In addition, there is a remarkable difference in antimicrobial resistance pattern among Pseudomonas species. P. aeruginosa and P. putida showed a similar resistance pattern, whereas P. fluorescens showed exceptionally lower resistance to trimethoprim/sulphamethoxazole and chloramphenicol than that of the other species. This study showed that prevalence of Pseudomonas spp. other than P. aeruginosa were 30.0% in bovine mastitis milk, and the occurrence rate of antibiotic resistance were similar or higher level, compared with the previous reports on the mastitisderived Pseudomonas spp. isolated in Korea.

• 대한수의학회지
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• 제33권4호
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• pp.753-756
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• 1993

Clinical and pathohistological findings in 16 cattle with mesotheliosis were described : pearshaped abdominal outline, poor nutritional and growth condition, reduced milk yield, diarrhea, apathy, increased peritoneal fluid, dyspnea, multiple tumors to the visceral serosa of abdominal intestine, and papilliform growth of mesotheliomas. Asbestos plays an etiologic role in bovine mesotheliosis. A proposal is made to use bovine mesotheliosis as a screening monitor for the protection of man.

• 한국가축번식학회지
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• 제20권4호
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• pp.371-378
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• 1997

본 연구는 인체 락토페린(hLF)을 우유 중으로 생산하는 형질전환 젖소의 개발에 관한 것이다. 이를 위한 모델 시스템으로서 락토페린 cDNAdhk 소의 베타-카제인 프로모터를 이용하여 형질전환 생쥐를 개발하였다. 발현 벡터의 락토페린에 대한 발현효율을 증가시키기 위하여 2개의 재조합 인트론을 삽입하였다. 20계통의 형질전환 생지를 개발하였는데 유즙에서의 락토페린 발현량은 1~200$\mu\textrm{g}$/ml이었다. hLF RNA의 발현 양상을 유선조직을 포함하여 뇌, 신장, 간 조직 등에서 조사하였을 때, 오직 유선에서만 발현되었을 뿐 아니라 엑손/인트론 경계 부위에서 정확하게 splicing되었다. hLF를 생산하는 형질전환 젖소를 개발하기 위하여 위에서 기술한 DNA를 소의 수정란에 미세주입한 후, 외과적 또는 비외과적 방법으로 대리모에 이식하였다. 한편, DNA가 주입된 수정란의 상태가 임신율에 미치는 영향을 조사하였다. 수정란을 최우수, 우수, 보통 등 3등급으로 나누었을 때, 각각의 임신율은 38.9, 15.4, 14.3%로 나타났다. 현재까지 유전자가 주입된 수정란을 대리모에 이식하여 태어난 35마리의 송아지 중, 30마리는 형절전환되지 않았으며 나머지는 현재 분석 중에 있다. 이상의 결과로 본 연구자들은 DNA가 미세주입된 젖소 수정란의 배양과 이식에 필요한 제반 기술을 확립하였으며, 아울러 임신율에 영향을 주는 여러 인자들에 대한 연구도 함께 조사하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권9호
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• pp.1327-1333
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• 2007

Lactose synthase catalyses the formation of lactose which is the major osmole of bovine milk and regulates the milk volume. Alpha-lactalbumin (${\alpha}$-LA) is involved in the synthesis of lactose synthase in the mammary gland. Therefore ${\alpha}$-LA is regarded as a plausible candidate gene for the milk yield trait. To determine whether ${\alpha}$-LA is associated with milk performance traits, 1,028 Chinese Holstein cows were used to detect polymorphisms in the ${\alpha}$-LA by means of single-strand conformation polymorphism (SSCP). Two nucleotide transitions were identified in the 5'flanking region and intron 3 of ${\alpha}$-LA. Associations of such polymorphisms with five milk performance traits were analyzed using a general linear model procedure. No significant associations were observed between these polymorphisms and the five milk performance traits (p>0.05). RH mapping placed ${\alpha}$-LA on BTA5q21, linked most closely to markers U63110, CC537786 and L10347 (LOD>8.3), which is far distant from the region of the quantitative trait locus (QTL) on bovine chromosome 5 for variation in the milk yield trait. In summary, based on our findings, we eliminated these SNPs from having an effect on milk performance traits.

• Journal of Dairy Science and Biotechnology
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• 제21권2호
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• pp.138-147
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• 2003

We here analyzed and proposed the structures of the N-linked sugar chains of PAS-7 from bovine milk fat globule membrane. The N-linked sugar chains were liberated from PAS-7 by hydrazinolysis and, after modifying the reducing ends with 2-aminopyridine (PA), were separated into one neutral (7N,55%) and two acidic (7M mono-, 43%; 7D, di-, 2%) sugar chain roups. The latter were converted into neutral groups (7MN and 7DN) by sialidase digestion. The structure of each of these PA-neutral sugar chains was determined by sugar analysis, sequential exoglycosidase digestion, partial acetolysis, and 1H-NMR spectroscopy. The results show that the 10 sugar chains were of the biantennary complex type with and without fucose. The structure of 7N2A one of the major sugar chains, was proposed as; [structure: see text] A structural comparison between PAS-6 and -7 indicated that although they shared the same protein core, their sugar moiety was markedly different, involving the existence of a different pathway during the post-transcriptional modification.

• Asian-Australasian Journal of Animal Sciences
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• 제17권9호
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• pp.1232-1235
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• 2004

In order to investigate the effect of recombinant bovine somatotropin (rbST) on blood metabolites and milk yield of lactating buffaloes, 30 lactating buffaloes after acclimatization for 30 days were divided into 2 groups as control (n=10) and experimental (n=20). Animals were injected 250mg of rbST (Boostin-250) on 0, $14^{th}$ and $28^{th}$ day subcutaneously at ischiorectal fosse, where as control animals were given placebo of 2 ml normal saline. Fortnightly blood samples were collected from 15 days prior to 60 days post injection to estimate different blood metabolites. Daily milk yield was recorded and weekly average yield of each animal was calculated. From this study, it was found that blood metabolites such as glucose, triglycerides, total proteins, albumin, globulin and electrolytes like sodium and potassium were not altered by rbST injection. However, there was a significant (p<0.05) decrease in blood urea nitrogen (BUN) concentration in experimental group as compared to that of control group. The weekly average milk yield was significantly (p<0.001) higher (25%) in rbST injected group over the control group.

• 한국축산식품학회지
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• 제36권4호
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• pp.452-457
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• 2016

Lactoferrin is a glycoprotein with various biological effects, with antibacterial activity being one of the first effects reported. This glycoprotein suppresses bacterial growth through bacteriostatic or bactericidal action. It also stimulates the growth of certain kinds of bacteria such as lactic acid bacteria and bifidobacteria. In this study, Asn-Leu-Asn-Arg was selected and chemically synthesized based on the partial sequences of bovine lactoferrin tryptic fragments. Synthetic Asn-Leu-Asn-Arg suppressed the growth of Pseudomonas fluorescens, P. syringae and Escherichia coli. P. fluorescens is a major psychrotrophic bacteria found in raw and pasteurized milk, which decreases milk quality. P. syringae is a harmful infectious bacterium that damages plants. However, synthetic Asn-Leu-Asn-Arg did not inhibit the growth of Lactobacillus acidophilus. It is expected that this synthetic peptide would be the first peptide sequence from the bovine lactoferrin C-lobe that shows antibacterial activity.