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《养殖与饲料.饲料世界》2005,(6):17-19
乳铁蛋白(Lactoferrin,LF)1960年首先由Groves从牛乳中分离获得,因与铁结合而呈红色,故称之为“红蛋白”。在发现之初,LF被认为是一种与铁的转运和存储有关的蛋白质,所以又称乳转铁蛋白。进一步研究表明,LF是一种分子量为70-80kD的糖蛋白,广泛存在于乳汁、唾液、泪液等外 相似文献
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工蜂监督是指工蜂通过识别蜂王和工蜂所产的卵,从而排除工蜂所产的卵,以此保证蜂王的后代为嫡系血亲,或者在一些行为中对工蜂和蜂王所产的卵进行区别性对待。现在流行的说法认为工蜂进行监督时是对卵产生的外激素进行识别。为证明工蜂可能通过识别两种卵的结构差异而进行监督,我们把蜂王和工蜂所产的单倍体和双倍体卵放在电子显微镜下进行观察对比。发现二者仅有非常微小的差异。因此排除了这种可能性。为进一步研究工蜂进行监督时的这种识别机制。我们对不同的卵进行了化学分析比较。发现蜂王所产的卵与工蜂所产的卵有一定的差异。如下:1.二者卵表面的化合物中含有碳氢化合物分子数量不同;2.蜂王卵上有一些特有的物质:如脂肪醇上的醋酸纤维,烯烃,特别是单核的甲基烯烃;这种差异可能就是工蜂能够识别二者所产卵的主要原因。 相似文献
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外源BT基因在棉花中的过量表达对根系分泌物中低分子量成分的影响 总被引:2,自引:0,他引:2
Most research in the past using genetically modified crops (GM crops) has focused on the ecological safety of foreign gene (i.e., the gene flow), gene products (for example, Bt (Bacillus thuringiensis) protein), and the safety of transgenic food for humans. In this study, changes in both the species and amounts of low-molecular-weight components in cotton (Gossypium hirsutum L.) root exudates after foreign Bt gene overexpression were investigated under different nutritional conditions. Transgenic cotton containing Bt (Bt-cotton), supplemented with all the mineral nutrients, secreted more organic acids than the wild-type cotton (WT). When nitrogen was removed from the full-nutrient solution, the amount of organic acids secretion of Bt-cotton was lesser than that of WT. The roots of the transgenic cotton secreted lesser amounts of amino acids and soluble sugars than the WT roots in the full-nutrient solution. Deficiencies of P and K caused a large increase in the total amino acid and soluble sugar secretions of both Bt-cotton and WT, with larger increases observed in Bt-cotton. Because transferring the foreign Bt gene into cotton can result in alterations in the components of the root exudates, with the effect varying depending on the nutritional status, the cultivation of genetically modified crops, such as Bt-cotton, in soil environments should be more carefully assessed, and the possible effects as a result of the alterations in the root exudate components should be considered. 相似文献
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溶菌酶(Lysozyme,EC3.2,17)是一种选择性的微生物细胞壁水解酶。1922年Fleming发现,在人的唾液和眼泪中存在溶解细菌细胞壁的酶,故命名为溶菌酶。此后在人和动物的多种组织、分泌液及某些植物和微生物中也发现了溶菌酶。其广泛存在于家禽和鸟类的蛋清中和哺乳动物的泪液、唾液、 相似文献