鳙鱼ARISTICHTHYS NOBILIS早期发育的一些生物化学上的变化

SOME BIOCHEMICAL CHANGES DURING THE EARLY DEVELOPMENT OF ARISTICHTHYS NOBILIS

本实验第一部分对鳙鱼卵及胚胎在不同的发育时期蛋白质合成的速度进行了研究,实验采用微量克氏定氮法,对鳙卵从未受精卵到受精卵、尾芽期和出膜期,共测定了十三个不同的发育时期。实验结果表明了在鱼的不同胚胎发育时期蛋白质合成速度有着明显的差异。 实验的第二部分对鳙鱼胚胎发育过程氨基酸组成和氨基酸含量进行了测定,其结果显示出鳙鱼卵和胚胎的各发育时期氨基酸的组分十分相似,但氨基酸的含量在各个时期是有差异的。

The first part of this investigation deals with the rates of protein synthesis during the different early developmental stages of the egg of Aristichtys nobilis by means of microanalysis, using the Kjeldahl nitrogen determination method. It comprised thirteen different development at stages, from the unfertilized egg to the tail-bud with the outgrowth-of-membrane stages, namely, the entire unfertilized egg, fertilized egg, cleavages up to 64-cell, late blastula, mid-gastrula, neurula and tail-bud with outgrowth-of-membrane stages. It is found that the rates of protein synthesis during the different embryonic stages of the fish was markedly variable. Although the total amount of protein was gradually increasing throughout the entire period, but there was an obvious high peak at the blastula and a marked low one at the neurula. By the tail-bud stage it went back quantitatively to the mid-gastrula condition at which the rate of protein synthesis reached its highest rate. The second part of the experiment deals with the combination of amino acids and also their quantily. It comprised eight developmental tages, namely, early blastula, mid-blastula, early gastrula, mid-gastrula, late neurula and somite stages. The qualitative calculations of amino acids wore determined by means of a high-speed automatic amino acid analyzer (Japan made 835-50). Data were taken from the homogeneous supernatant fluid. The results showed that the component of amino acid were quite similar at all the stages of the egg and the embryo. They are Tau. Asp. Thr. Glu. Gly. Ala. Val. He. Leu, Tyr. Phe, Lys, His Arg. Pro, Cys. Met, and Ser, among which Cys, and Met. varied considerably. Cys. appeared at the cleavage and early gastula stages only. Met. appeared at the early gastrula but disappeared at gastrula. For the rest of the following stages, with the quantitative analysis, Glu, appeared to be highest. and Pro. the lowest in amount at all the stages of the egg and the embryo studied.