• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.801-808
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• 2002

Proteolytic activities of some commercial milk clotting enzymes(rennet, trypsin, pepsin, papain W-40, neutrase 1.5 and protease S) in bovine skim milk containing 0.02% $CaCl_2$ were determined by measuring DH(Degree of Hydrolysis), NPN(Non Protein Nitrogen) and by comparing patterns of SDS-PAGE(Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis). The DH of microbial enzymes(neutrase 1.5 and protease S) and trypsin in bovine skim milk were higher than those of pepsin and papain W-40. The amounts of NPN in the milk treated with trypsin and the other animal enzymes(rennet and pepsin) showed the highest and lowest degrees of proteolysis, respectively. SDS-PAGE showed that trypsin and protease S hydrolyzed $\alpha$-lactalbumin and papain W-40 hydrolyzed $\beta$-lactoglobulin slightly, while neutrase 1.5 hydrolyzed both $\alpha$-lactalbumin and $\beta$-lactoglobulin after treating for 90 min. Trypsin and protease S easily hydrolyzed ${\alpha}_s$-casein and $\beta$-casein, which were not hydrolyzed by rennet. Papain W-40 hydrolyzed $\kappa$-casein more than rennet as shown in SDS-PAGE. Based on the results of the experiments, the DH and NPN of trypsin, neutrase 1.5 and protease S were shown to be higher than those of the other enzymes. The SDS-PAGE patterns of papain W-40 and neutrase 1.5 were similar with that of rennet.

• BMB Reports
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• v.31 no.4
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• pp.413-417
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• 1998

Transgenic mice containing a bovine ${\beta}-Casein/Human$ lysozyme fusion gene (pBZ) were generated in order to produce human lysozyme in their milk. The expression vector was a quadripartite fusion consisting of a 2 kb upstream DNA of the bovine ${\beta}-casein$ gene, human lysozyme gene, intron II of the rabbit ${\beta}-globin$ gene, and the polyadenylation/termination signals of SV40 DNA. Fertilized mouse zygotes were microinjected with pBZ, then transferred into the oviduct of foster mothers. Out of 20 mice born, 11 survived until postweaning and three were identified as positivetransgenic by Southern blot analysis (one male and two females). The founder mice were mated to BCFl mice to produce transgenic progeny. It was confirmed by RT-PCR and Northern blot analyses that the transgene was specifically expressed in the mammary gland of the founder mice. Furthermore, the artificial introns within the transgenic RNA was proven to be correctly spliced out as judged by RT-PCR analysis. These results indicated that transgenic mice generated in this study properly expressed the human lysozyme RNA in their mammary gland.

• BMB Reports
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• v.28 no.1
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• pp.57-61
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• 1995

The expression of a recombinant human lactoferrin is reported in mouse HC11 mammary epithelial cells. Expression of human lactoferrin (hLF) was achieved by placing its cDNA under the control of the bovine ${\beta}$-casein gene. To improve the hLF expression level in a cell culture system, two artificial introns were also introduced to construct expression vectors. One intron was a hybrid-splice signal consisting of bovine ${\beta}$-casein intron 1 and rabbit ${\beta}$-globin intron II. The other intron was a DNA fragment spanning intron 8 of the bovine ${\beta}$-casein gene. The hybrid intron moderately elevated hLF expression, whereas intron 8 alone did not express any detectable amount of hLF as judged by Northem and Western blot analyses. When the two introns were used together they contributed to a synergistic elevation of hLF expression. These data indicate that artificial introns on both sides of the hLF cDNA were necessary to increase expression of cDNA.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.92-98
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• 2001

Lactofenicin is an antibacterial peptide fragment (about 5 kD) derived from lactoferrin (80 kD) that displays the various biological functions. The production of a human lactoferricin (Lactoferricin H) in mouse HC11 mammary epithelial cells was achieved by placing its cDNA under the control of the bovine ${\beta}$-casein gene. To express lactoferricin H in this cell culture system, constructed a hybride-splice signal consisting of bovine ${\beta}$-casein intron I and rabbit ${\beta}$-globin intron II, and a DNA fragment spanning intron 8 of the bovine ${\beta}$-casein gene. Expression of lactofenicin H from this expression vector was identified by RT-PCR, northern and dot blot analysis. RT-PCR using total RNA of HC11 cells transfected with pBL1-cin expression vector yielded a product identified as having a size of the 150bp. Northern blot analysis was identified about 2.3 kb. In dot blot analysis, recombinant lactofenicin H was recognized with anti-human lactofrrnin polyclonal antibody.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2003.10a
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• pp.89-89
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• 2003

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.45-45
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• 2004

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.541-547
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• 1993

A phage clone containing the partial ${\alpha}_{S1}$-casein gene was isolated from a bovine genomic library by using mixed probes of ovine ${\alpha}_{S1}$-, ${\beta}$- and ${\kappa}$-casein cDNAs. Restriction enzyme mapping analysis for 14.6 kb revealed that the map was in conflict with the report of Meade et al. (1990), especially in the 3'-end fragment. Sequence analysis of 12.6 kb revealed a high AT/GC ratio (1.64); we have identified eight exon sequences according to the bovine ${\alpha}_{S1}$-casein cDNA sequence. The same exon/intron splice junction sequence was observed between these exons. We suggest that the bovine ${\alpha}_{S1}$-casein gene night contain a minimum of 18 exons and the full length is approximately 18-19 kb.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.201-211
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• 1989

This experiment was carried out to study the practical utility of Mucor rennet in making Blue cheese and to investigate the changes in the level of various nitrogen compounds. 1. The Mucor rennet cheese, the calf rennet cheese and the mixed rennet cheese did not show any significant difference in their yields. 2. The dry matter contents of Blue cheese was increased during the ripening and the levels of Mucor rennet did not have any influence in these respect. 3. The water soluble nitrogen contents of Blue cheese increased during ripening. On 0 day of ripening the Mucor rennet cheese contained water soluble nitrogen than the calf rennet cheese. On 40 days of ripening the mixed cheese contained less water soluble nitrogen than the calf rennet cheese. 4. Non protein nitrogen, peptone amino nitrogen, water soluble protein nitrogen, proteose nitrogen and peptone nitrogen appeared to contain similar levels of water soluble nitrogen. 5. The results of electrophoresis indicated a greater degredation on as-casein and ${\beta}$-casein in the Blue cheese made with Mucor rennet than in those made with calf rennet. On 60 days of ripening the mixed cheese more casein than did the Mucor rennet cheese. 6. The free amino acid contents of the Mucor rennet cheese was higher than the calf rennet cheese at 60 days of ripening.

• Journal of Dairy Science and Biotechnology
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• v.35 no.2
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• pp.105-111
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• 2017

There have been numerous reports indicating that milk proteins influence immune functions. Colostrum refers to the breast milk of mammals, secreted starting from the fourth or fifth day after delivery. It has abundant nutrition for the survival of newborn infants. Most importantly, it contains bioactive substances with growth-stimulating and antibiotic, functions. Thus, the colostrum has various physiological roles. This study measured the differences in the composition of colostrum derived from dairy cattle, hanwoo, porcine, and goat sources. The results showed that immunoglobulin, lactoferrin, lactoperoxidase, serum albumin, IgG heavy chain, and IgG light chain were significantly higher in the colostrum of dairy cattle, hanwoo, and goats, but low in porcine colostrum. There was no significant difference in ${\alpha}_{S2}$-casein, ${\alpha}_{S1}$-casein, ${\beta}$-casein, ${\kappa}$-casein, ${\beta}$-lactoglobulin, and ${\alpha}$-lactalbumin contents until seven days after birth. However, porcine colostrum showed high contents of all proteins from the first day to the second day after delivery.

• Reproductive and Developmental Biology
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• v.30 no.4
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• pp.293-299
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• 2006

In order to generate transgenic goats expressing human growth hormone (hGH) in their mammary glands, goat ${\beta}-Casein/hGH$ hybrid gene was introduced into goat zygotes by pronuclear microinjection. DNA-injected embryos were transferred to the oviduct of recipients at 2-cell stage or to the uterus at morula/blastocyst stage after cultivation in glutathione-supplemented mSOF medium in vitro. Pregnancy and survival rate were not significantly different between 2-cell embryos and morula/blastocysts transferred to oviduct and uterus, respectively. One transgenic female goat was generated from 153 embryos survived from DNA injection. Southern blot analysis revealed that the transgenic goat harbored single-copy transgene with a partial deletion in its sequences. Despite of the partial sequence deletion, the transgene was successfully expressed hGH at the level of $72.1{\pm}15.1{\mu}g/ml$ in milk throughout lactation period, suggesting that the sequence deletion had occurred in non-essential part of the transgene for the transgene expression. Unfortunately, however, the transgene was not transmitted to her offspring during three successive breeding seasons. These results demonstrated that goat ${\beta}-casein/hGH$ gene was integrated into the transgenic goat genome in a mosaic fashion with a partial sequence deletion, which could result in a low level expression of hGH and a failure of transgene transmission.