Hagedorn Mary, Carter Virginia L, Ly Steven, Andrell Raymond M, Yancey Paul H, Leong Jo-Ann C, Kleinhans Frederick W
Department of Reproductive Sciences, Smithsonian National Zoological Park, Washington, DC 20008, USA.
Physiol Biochem Zool. 2010 Jan-Feb;83(1):157-66. doi: 10.1086/648484.
Coral species throughout the world are facing severe local and global environmental pressures. Because of the pressing conservation need, we are studying the reproduction, physiology, and cryobiology of coral larvae with the future goal of cryopreserving and maintaining these organisms in a genome resource bank. Effective cryopreservation involves several steps, including the loading and unloading of cells with cryoprotectant and the avoidance of osmotic shock. In this study, during the time course of coral larvae development of the mushroom coral Fungia scutaria, we examined several physiologic factors, including internal osmolality, percent osmotically active water, formation of mucus cells, and intracellular organic osmolytes. The osmotically inactive components of the cell, V(b), declined 33% during development from the oocyte to day 5. In contrast, measurements of the internal osmolality of coral larvae indicated that the internal osmolality was increasing from day 1 to day 5, probably as a result of the development of mucus cells that bind ions. Because of this, we conclude that coral larvae are osmoconformers with an internal osmolality of about 1,000 mOsm. Glycine betaine, comprising more than 90% of the organic osmolytes, was found to be the major organic osmolyte in the larvae. Glycerol was found in only small quantities in larvae that had been infected with zooxanthellae, suggesting that this solute did not play a significant role in the osmotic balance of this larval coral. We were interested in changes in cellular characteristics and osmolytes that might suggest solutes to test as cryoprotectants in order to assist in the successful cryopreservation of the larvae. More importantly, these data begin to reveal the basic physiological events that underlie the move from autonomous living to symbiosis.
世界各地的珊瑚物种都面临着严峻的局部和全球环境压力。鉴于迫切的保护需求，我们正在研究珊瑚幼虫的繁殖、生理学和低温生物学，未来目标是在基因组资源库中对这些生物进行冷冻保存和维持。有效的冷冻保存涉及几个步骤，包括用冷冻保护剂加载和卸载细胞以及避免渗透压休克。在本研究中，在蘑菇珊瑚盾形陀螺珊瑚幼虫发育的时间进程中，我们检测了几个生理因素，包括内部渗透压、渗透活性水百分比、黏液细胞的形成以及细胞内有机渗透剂。细胞的非渗透活性成分V(b)在从卵母细胞到第5天的发育过程中下降了33%。相比之下，对珊瑚幼虫内部渗透压的测量表明，从第1天到第5天内部渗透压在增加，这可能是由于结合离子的黏液细胞发育的结果。因此，我们得出结论，珊瑚幼虫是渗透顺应者，内部渗透压约为1000毫渗摩尔。甘氨酸甜菜碱占有机渗透剂的90%以上，被发现是幼虫中的主要有机渗透剂。在感染了虫黄藻的幼虫中仅发现少量甘油，这表明这种溶质在这种幼虫珊瑚的渗透平衡中没有发挥重要作用。我们对细胞特征和渗透剂的变化感兴趣，这些变化可能暗示可作为冷冻保护剂进行测试的溶质，以协助成功冷冻保存幼虫。更重要的是，这些数据开始揭示从自主生活到共生转变所依据的基本生理事件。
