Maga E A, Anderson G B, Murray J D
Department of Animal Science, School of Veterinary Medicine, University of California, Davis 95616, USA.
J Dairy Sci. 1995 Dec;78(12):2645-52. doi: 10.3168/jds.S0022-0302(95)76894-1.
Transgenic mice were used as model systems to evaluate the impact of human lysozyme expression in the mammary gland. We previously generated two lines of transgenic mice that express human lysozyme mRNA in the mammary gland under the tissue-specific and developmentally correct control of the bovine gene promoter for alpha s1-casein. Concentrations of human lysozyme protein in milk of transgenic mice varied from .25 to .71 micrograms/microliters of milk. Human lysozyme secreted into mouse milk retained its antimicrobial activity, as determined by a denaturing polyacrylamide gel activity assay. The physical and functional properties of the milk were also altered, because mouse milk containing human lysozyme had a 35% decrease in rennet clotting time, a smaller median micelle size (157 nm vs. 172 nm), and a 2.5- to 3-fold greater gel strength than control milk. From these results, we conclude that the use of transgenic animals producing lysozyme in the milk is feasible and potentially useful to the dairy industry.
转基因小鼠被用作模型系统，以评估人溶菌酶在乳腺中表达的影响。我们之前培育了两系转基因小鼠，它们在牛αs1-酪蛋白基因启动子的组织特异性和发育正确的控制下，在乳腺中表达人溶菌酶mRNA。转基因小鼠乳汁中人溶菌酶蛋白的浓度在每微升乳汁0.25至0.71微克之间。通过变性聚丙烯酰胺凝胶活性测定法确定，分泌到小鼠乳汁中的人溶菌酶保留了其抗菌活性。乳汁的物理和功能特性也发生了改变，因为含有人溶菌酶的小鼠乳汁的凝乳酶凝结时间缩短了35%，胶粒中位尺寸更小（157纳米对172纳米），并且凝胶强度比对照乳汁大2.5至3倍。从这些结果中，我们得出结论，利用转基因动物在乳汁中产生溶菌酶对乳制品行业是可行的且可能有用。
