Biochemical Studies on the Cyst Formation of Marine Phytoflagellates

利用富含esm的海水进行实验室培养，测定了古查托纳菌（Hada） Ono、卡特纳亚历山大菌（Whedon et Kofoid） Balech和trochoidea Scrippsiella (Stein) Loeblich III的核苷酸及相关化合物的变化。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早期对数期显著增加，之后它们显著下降，并在固定期趋于稳定。在固定期，链状假单胞菌和trochoidea假单胞菌囊内的核苷酸和相关化合物含量均高于营养细胞。原木期胞内GTP/ATP比值低于其他生长时期。在培养的各个阶段，trochoidea的GTP/ATP比值都远远大于catenella。在棘球蚴囊中，GTP/ATP比值高于营养细胞。接种新培养基后，古参的能量荷值[EC=(ATP+1/2ADP)/(ATP+ADP+AMP)]显著降低。在对数阶段，它保持在0.6左右，停止生长后，它缓慢下降到0.5左右。在接种后，catenella和trochoidea的EC值显著增加。链状芽孢杆菌和trochoidea芽孢杆菌包囊的EC值低于营养细胞。这些结果可能与囊肿的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.