A biochemical study of the growth of Drosophila melanogaster
A biochemical study of the growth of Drosophila melanogaster
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果蝇生长的生化研究
DOI：
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发表时间：
1966
期刊：
影响因子：
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通讯作者：
F. W. Robertson
中科院分区：
文献类型：
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作者：
R. Church;F. W. Robertson
1.对一株野生黑腹果蝇从孵化到成虫的生长过程进行了研究。湿重和干重、蛋白质和蛋白质组分、脂类、RNA和DNA已连续测定。2.所有的估计都是在规定的培养基中轴向生长的动物上进行的。当幼虫可以自由地在洞里钻洞时，这种培养基能允许生长，其生长速度与在活酵母培养基上一样快。3.不溶性蛋白质和甲壳素氮在蚕蛹后期达到最大值，占总氮的70%左右，此时可溶性氮含量最低。氨基酸组分在三龄初达到最大值。4.水分含量在一龄末下降到活重的70-75%，二龄时达到最大值，预蛹时急剧下降到66%左右。5.在幼虫的生长过程中，总脂在体重中所占的比例越来越大，从幼虫的6%左右增加到化蛹时的15%左右。6.在幼虫整个生命周期中，RNA的增长曲线遵循干重和蛋白质的增长曲线。在前两个龄期，RNA与蛋白质的比率下降。7.DNA含量的增加遵循与RNA类似的路径。RNA/DNA比率在卵孵化后24小时达到最大值，到84小时下降到该值的一半左右，此后基本保持不变。8.不同发育阶段幼虫体内蛋白质、RNA和DNA的增长速率存在显著差异。对于蛋白质来说，这种比率很高，而且一直在增加，直到大约36小时后，在幼虫剩余的生命中，它迅速下降。这两种核酸的增长速度在三龄早期降到最低，大约在临界大小的时候，然后在想象盘的增殖过程中增加，最后在幼虫生命结束时下降。8.将这些数据与其他果蝇品系和其他种类昆虫的证据进行了比较。在后一种情况下，到目前为止，所有的双翅目昆虫在生长过程中核酸的增加都遵循着类似的趋势。9.通过脉冲标记和蔗糖梯度分析，跟踪了从卵到成虫发育过程中的RNA合成。发育不同阶段，快速标记的高分子物质的数量不同，这在新孵化的幼虫和中三龄幼虫中最为明显，此时总RNA的合成速度较快。
1. The growth of a wild strain of Drosophila melanogaster has been studied from the time of hatching from the egg to the adult. Wet and dry weights, protein and protein fractions, lipids, RNA and DNA have been determined at successive intervals. 2. All estimates have been carried out on animals grown axenically on defined medium. The medium has been shown to permit growth which is as fast as on live yeast medium when the larvae can burrow freely. 3. Insoluble protein and chitin nitrogen reach a maximum of about 70% total nitrogen in the late pupa, at which time the soluble nitrogen reaches its lowest level. The amino acid fraction reaches a maximum in the early third instar. 4. The water content declines from 70–75% of the live weight at the end of the first instar, rises to a maximum during the second instar and declines sharply to about 66% at the prepupal stage. 5. Total lipids represent an increasing proportion of body weight during larval growth, increasing from about 6% in young larvae to about 15% at pupation. 6. The curve of RNA increase follows the dry weight and protein curves during larval life. The ratio of RNA to protein declines during the first two instars. 7. The increase in DNA content follows a path similar to that of RNA. The RNA/DNA ratio reaches a maximum 24 hours after hatching from the egg, declines to about half this value by 84 hours, and remains more or less constant thereafter. 8. The rates of increase of protein, RNA and DNA during successive periods of larval life show striking differences. For protein the rate is high and increasing until about 36 hours after which it declines rapidly during the rest of larval life. For both nucleic acids the rate of increase falls to a minimum in the early third instar, about the time of the critical size, then increases during proliferation of the imaginal discs and finally declines at the end of larval life. 8. The data are compared with evidence from other strains of Drosophila and from other species of insect. In the latter case, it appears that all the Diptera, so far examined, follow a similar trend in the increase of the nucleic acids during growth. 9. RNA synthesis has been followed during development from egg to adult with the aid of pulse-labeling and sucrose gradient analysis. Developmental stages differ in the amount of rapidly labeled high molecular weight material which is most evident in newly hatched larvae and in mid-third instar larvae, at times when the rate of synthesis of total RNA is high.