果蝇衰老和生殖对饲喂甲硫氨酸效应研究
毕业论文关键词：甲硫氨酸；黑腹果蝇；寿命；繁殖能力
Effects of Different Concentrations of Methionine on the
Growth and Reproductive in Drosophila
Abstract: Objective of this paper is to study different concentrations acid methionine on the lifespan and reproductive capacity of Drosophila. Method: While setting the control group that is not added methionine, three different concentrations of methionine are added in the mediums(high concentration group:0.1%, middle concentration: 0.01%, lower concentration: 0.001%), besides, we also set the control group. We record the number of surviving flies in different mediums containing different concentrations of methionine. At the same time, we use the method of ether anestesia to collect unmated Drosophila melanogaster to select flies in the similar size and appearance, what’s more, half of them are females. Besides, different concentrations of methionine are added into defferent mediums. And we measure effects of different concentrations of methionine on reproductive capacity of Drosophila. Results: In low concentration, Drosophlia can survive the longest and the fecundity are similar with the control group. With the concentration increasing, the lifespan of Drosophila becomes shorter and shorter, besides, the fecundity have also been reduced. Conclusion: Low concentration of methionine extends the life of Drosophila to some extent. On the contrary, high concentration of methionine decreases the reproductive capacity of Drosophila.
Key words: methionine; Drosophila melanogaster; lifespan; reproductive capacity
目 录
摘要 1
引言 2
1.实验材料和仪器 3
1.1主要实验试剂 3
1.2主要实验器材 3
1.3果蝇品系 3
1.4果蝇培养基的配方 3
2.实验方法 3
2.1果蝇培养基的制备 3
2.2培养基的处理及分装 4
2.3果蝇的收集及处理 4
2.4果蝇转瓶及麻醉 5
2.5果蝇的培养 5
3.实验的观察和数据统计 5
3.1果蝇寿命的实验 5
3.2果蝇生殖能力的实验 5
3.3数据处理 6
4.结果 6
4.1在热胁迫下果蝇寿命 6
4.2常温下甲硫氨酸对果蝇生长发育的影响实验 8
5.讨论 8
参考文献 10
致谢 11
果蝇衰老和生殖对饲喂甲硫氨酸的效应研究 引言
甲硫氨酸是人体内的一种必需氨基酸,参与了蛋白质的合成。因为它不能在机体自身中生成，所以必须从外部获得。当机体内缺乏甲硫氨酸时就会导致体内蛋白质合成受阻，进而对机体造成损害[1]。体内的氧自由基造成的膜脂质过度氧化能够导致机体的多种损害。脂质过氧化物会严重损害初级溶酶体膜和次级溶酶体膜，从而使溶酶体中的酸性磷酸酶释放，酸性磷酸酶具有水解功能，能够损害细胞和线粒体膜等多种重要细胞器，而甲硫氨酸就是通过多种途径抗击这些损害。甲硫氨酸是一种含硫的必需氨基酸，生物体必须将D-型甲硫氨酸转化为L-型才能被机体所利用，这与生物体内各种含硫化合物的代谢过程密切相关。它在生物体内从ATP接受腺苷基变成S-腺苷酰甲硫氨酸再进行甲基转移。同型半胱氨酸失去了甲基在由胱硫醚变成了半胱氨酸。当机体内缺乏甲硫氨酸时，会引起食欲不振、体重减轻或生长缓慢、肝脏铁堆积和肾脏肿大等现象，最终会导致肝坏死或肝脏的纤文化[2,3]。甲硫氨酸是必需氨基酸，其重要功能在很早之前就已经引起人们的重视，但有关甲硫氨酸对果蝇的寿命与生殖的影响尚未见报道。
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