Microbial control of growth, differentiation, metamorphosis and settlement of marine organisms.

在这项研究中，我们试图弄清变态和定居的机制，并寻找和分离参与这些现象的微藻和细菌，并鉴定它们的生物活性物质。研究结果如下：1.内分泌系统II在控制鱼类生长发育中起着至关重要的作用。在中上层卵子物种卵黄吸收的最后阶段，甲状腺和脑垂体腺发生分化。肾间组织的出现晚于两个腺体，大约在牙鲆孵化后2周左右。免疫组织化学技术显示GH和PRL的产生早于组织学可检测到的垂体腺。组织中TH含量在受精时处于较高水平，此后随着胚胎发育而显著降低。随着法律规定后的生长和发育，它们逐渐增加，在比目鱼的变态过程中明显增加。在一些比目鱼中，皮质醇和…的组织浓度More o表现出明显的激增，但时间明显早于TH。这些激素水平的动态变化似乎与身体结构、行为和生态变化密切相关。调查了多种海洋微生物对比目鱼(Paralichthys Obivaceus)幼体的定居作用。海洋不动杆菌SS6-2和雷氏不动杆菌A86具有良好的沉降性。活性物质主要存在于丙酮或乙醇不溶组分中。二甲基磺基丙酸酯(DMSP)是海水中含量最丰富的挥发性硫化物--二甲基硫(DMS)的前体。各种海洋大型藻类(特别是红藻门)和微藻(特别是浮游藻门和高藻门)都含有DMSP。‘DMSP对几种鱼类的生长、摄食和推进力均有促进作用。隐藻体内甲硫氨酸生物合成DMSP的途径甲硫氨酸首先被甲硫氨酸脱羧酶脱羧，这需要吡哆醇磷酸盐。我们现在正在努力提纯这种酶。采用聚乙二醇法，将含有新霉素磷酸转移酶II(NPTII)基因和β-葡萄糖苷酶(GUS)基因的线性化表达载体pBI121转化无细胞壁突变株。这个转换过程非常简单。获得了卡那霉素抗性转化细胞。从转化子中提取的DNA斑点表明，除了GUS基因外，PNT II基因已经整合。我们现在正在尝试制造转基因的孔雀石榴叶状体，它可以产生金枪鱼的生长激素。较少

In this study we attempted to make clear a mechanism of metamorphosis and settlement, and to search and isolate microalgae and bacteria participating in these phenomena, and to identify' their bioactive substances. The results obtained are as follows ;1. The endocine system ii of fundamental importance in controlling development and growth of fishes. Thyroid and pituitary glands differentiate during the final phase of yolk absorption in pelagic -egg species. Interrenal tissues appear later than both glands, around 2 weeks after hatching in Japanese flounder. Immumehistochemical techniques revealed production of GH and PRL prior to the time when the pituitary is histologically detectable. Tissue TH concentrations were at higher levels at fertilization, thereafter markedly reduced with embryonic development. They gradually increased with postlawal growth and development, and appreciably increased during metamorphosis in flatfishes. In some flatfishes, tissue concentration of cortisol als … More o exhibited a prominent surge, but the timing was significantly earlier than that of TH. These hormone level dynamics appeared to be intimately related to body structual, behavioral and ecological changes.2. Many marine microorganisms which stimulate settlement of flounder (Paralichthys obivaceus) larvae were surveyed. Marine Acinetobacter SS6-2 and Raphidophyta Chattonella antiqua a86 were effective on the settlement. The active substances were found in acetone or ethanol insoluble fraction.3. Dimethylsulfoniopropionate (DMSP) is the precursor of dimethylsulfide (DMS) which is the most abundant volatile sulfur compound in seawater. Various species of marine macroalgae (especially Rhodopohyta) and microalgae (especially Dinophyta and Haptophyta) contain DMSP. ' DMSP has promoting effect on growth, feeding and thrust power of several fishes. The biosynthetic pathway of DMSP from methionine in Crypthecodinium cohnii (Dinophyta). Methionine is first decarboxylated by methionine decarboxylase which requires pyridoxyal phsphate. We are now trying to purify this enzyme.4. Polyethyleneglycol method was applied to tranformation of the linearized plasmid pBI121 which contains the neomycin phosophotransferease II (NPTII) gene and beta-gluconidase (GUS) gene into the cell wall-less mutant of Chiamydomonas reinhardtii. This transformation procedure is very simple. Cells tranformed to kanamycin resistance were obtained. Southem blots of DNA from the transformant demonstrate the integration of the PNT II gene but GUS gene. We are now trying to make transgenic thalli of Ulva pertusa which can produce the growth hormone of tuna. Less