Biochemical Studies on the Cyst Formation of Marine Phytoflagellates

用富含ESM的海水进行实验室培养，测定了安提瓜(Hada)Ono、链状亚历山大藻(Alexandrium catenella(Whedon Et Kofoid)Balech)和锥状斯氏藻(Scrippsiella trochoei(Stein)Loeblich III)在生长过程中核苷酸及相关化合物的变化。结果表明，这些植物鞭毛虫细胞内核苷酸及相关化合物的总含量在迟滞期和对数早期显著增加，之后显著下降，在稳定期基本保持不变。在稳定期，链霉菌和锥状链霉菌包囊中的核苷酸及相关化合物含量均高于营养细胞。Cntiqua在对数生长期细胞内GTP/ATP比值低于其他生长期。在整个培养过程中，锥状链霉菌的GTP/ATP比值均远大于链球菌。在锥虫包囊中，GTP/ATP比值高于营养细胞。接种到新的培养基中后，能荷值[EC=(ATP1/2ADP)/(ATPADP AMP)]显著降低。在对数阶段维持在0.6左右，停止生长后缓慢下降到0.5左右。链霉菌和锥状链霉菌接种后EC值显著升高。卡氏不动杆菌和锥形链球菌包囊的EC值低于营养细胞。这些结果可能是由于胞囊的代谢活性低于营养细胞所致。

The variations of nucleotides and related compounds in chattonella antiqua (Hada) Ono, Alexandrium catenella (Whedon et Kofoid) Balech and Scrippsiella trochoidea (Stein) Loeblich III were determined during growth in laboratory culture using ESM-enriched seawater. The results clearly showed that total cellular contents of nucleotides and related compounds of these phytoflagellates increased greatly during lag and early log phases, after which they decreased markedly and became approximately constant during the stationary phase. The nucleotides and related compounds in cysts of both A.catenella and S.trochoidea were higher than those of vegetative cells during the stationary phase. The intracellular GTP/ATP ratios in C.cntiqua during the log phase were lower than that of other phases of growth. The GTP/ATP ratios of S.trochoidea were much greater than that of A.catenella through the all stages of the culture. In the cyst of S.trochoidea, the GTP/ATP ratio was higher than that in vegetative cell. The value of energy charge [EC=(ATP+1/2ADP)/(ATP+ADP+AMP)] of C.antiqua decreased notably after inoculation into a new culture medium. It was maintained at the value of about 0.6 during the log phase, and after cessation of growth it declined slowly to a value of about 0.5. In A.catenella and S.trochoidea, the EC values increased remarkably after the inoculation. The EC values in cysts of A.catenella and S.trochoidea were lower than those in vegetative cells. These results may depend on the lower metabolic activity in cyst than that in vegetative cell.