Biochemical Studies on the Cyst Formation of Marine Phytoflagellates

在实验室培养条件下，研究了富含ESM的海水对古查顿藻（Chattonella antiqua（Hada）Ono）、链状亚历山大藻（Alexandiumcatenella（WhedonetKofoid）Balech）和锥状斯氏藻（Scrippsiella trochoidea（Stein）Loeblich III）生长过程中核苷酸及相关化合物的影响。结果清楚地表明，这些植物鞭毛虫的核苷酸和相关化合物的总细胞含量在滞后期和对数早期大大增加，之后，他们显着下降，并在稳定期变得几乎恒定。在静止期，链状放线菌和锥状放线菌孢囊内的核苷酸及相关化合物含量均高于营养细胞。在对数生长期，栉孔扇贝胞内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比值均远大于链状链霉菌。锥状链霉菌孢囊内GTP/ATP比值高于营养细胞。接种到新培养基中后，能荷值[EC=（ATP+1/2ADP）/（ATP+ADP+AMP）]显著降低。在对数生长期，它保持在约0.6的值，在停止生长后，它缓慢下降到约0.5的值。在链状链霉菌和锥状链霉菌中，接种后EC值显著增加。链状链藻和锥状链藻孢囊的EC值低于营养细胞。这些结果可能与孢囊内代谢活性低于营养细胞有关。

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.