Fertilization and Development of the Lancelets

在合作研究组中，我们主要负责采集成熟文昌鱼，进行实验室饲养，并为不同的研究目的提供精子、卵子、各期胚胎及组织等材料。在1995年和1996年的文昌鱼产卵季节，我们几乎每天采集成鱼5 kg，提供足够的实验材料供观察和分析。卵没有明显的卵质分离。当两个卵裂球中的一个在2-细胞期分离时，胚胎表现出调节性发育。本研究对文昌鱼与早期胚胎发生相关的同源异型基因LIM、肌肉蛋白肌钙蛋白T和与胚胎发育相关的肌钙蛋白样蛋白酶的同源基因进行了克隆。LIM同源框基因的分离目前正在进行中，通过确定PCR产物的核苷酸序列，然后筛选cDNA文库，肌钙蛋白T目前正在筛选cDNA文库，但我们没有孵化酶的克隆。希望我们能在改造后的克隆成功，在未来的时间可能出现的问题。本文研究了离子通道拮抗剂对文昌鱼精子活力和去质膜精子活力的影响。结果表明，其受精、发育和精子活力与海洋无脊椎动物相似。研究了文昌鱼rRNA基因重复单位的遗传多样性。我们检测了18 S rDNA和5.8S rDNA之间的间隔区长度的变化。

In the collaboration research group, we are mainly in charge of collecting mature amphioxus, keeping and feeding them in the lab and supplying the materials such as sperm, eggs, embryos from various stages and tissues etc.for deferent purposes of research. During the amphioxus spawning seasons in 1995 and 1996, we collected 5 kg of the adult amphioxus each season and supplied enough experimental materials for observation and analysis almost everyday.Embryogenesis of amphioxus was observed and recorded. The eggs do not show conspicuous ooplasmic segregation. The embryos showed regulative development when one of two blastomers were isolated at the 2-cell stage. We had some trials to clone the amphioxus gene homolog of the homeotic gene LIM,which is related to eary embryogenesis, troponin T which is muscle protein and astacin-like protease which is related to haching embryo. Isolation of LIM homeobox gene is now under way by determining nucleotide sequence of the PCR products, followed by screening of the cDNA library, and troponin T is now screening of the cDNA library, but we have no clone of the hatching enzyme. It is hoped that we succeed in the cloning after reformation of the possible problems in the next time. The effects of ion channel antagonists on the motility of amphioxus sperm and motility of the sperm of which the plasma membrane was removed using detergent were investigated. Obtained resutls suggest that fertilization, development and sperm motility are similar to that of marine invertebrates. Genetical variety of rRNA gene (rDNA) repeated units was studied in amphioxus. We detected the variety of the length of the internal spacer region between 18S rDNA and 5.8S rDNA.