SYMPOSIUM: Amphibian Metamorphosis: An Integrative Approach:American Society of Zoologists Meeting in Washington, D.C., January 1996

小行星9529567 本次研讨会汇集了生态学、内分泌学、发育生物学和分子生物学方面的专家，讨论两栖动物变态的综合研究。变态是所描述的最显著的生物过程之一。在两栖动物的变态过程中，一种动物（蝌蚪）实际上变成了另一种动物（成年青蛙）。除了明显的外部变化，如尾巴的吸收，四肢的生长和陆地生命的开始，还有许多其他不太明显的变化。蝌蚪是典型的素食主义者，而成年人以昆虫或小动物为食，因此肠道的结构和所有的酶在变态时发生变化;免疫系统被破坏并重建以适应青蛙;鳃被吸收并被肺取代;血红蛋白的结构（携氧分子）发生变化;眼睛的结构和功能从水下看东西转变为更适合在空气中看东西;皮肤腺（产生粘液、重要的抗生素和毒素）发育;生殖器官发育;等等。所有结构和功能的变化都受激素的调节。虽然甲状腺激素是刺激这些变化的主要激素，但其他激素如催乳素和应激激素皮质酮也调节发育。所有这些激素都通过调节基因来发挥作用，关闭“蝌蚪基因”，打开“青蛙基因”。此外，这些激素还受到外部因素的控制，如温度，食物水平，水质，捕食者的存在和人口密度。由于这些复杂的相互作用，跨层次的组织，环境-生物基因，变态是一个很好的综合研究过程。两栖动物可以作为研究环境变化如何影响生理过程以及研究基因调控的模型。两栖动物的变态是理解所有脊椎动物（包括人类）发育和基因作用的重要模型，因为变态时的发育过程可以直接观察到（不像其他动物的胚胎发育通常发生在卵内或母体内）。此外，了解生理和基因表达对环境变化的反应变化对于了解动物如何适应环境变化至关重要。这一认识将导致更好地利用两栖动物作为环境退化的指标，这是迫切考虑到最近全球两栖动物种群下降的证据。

9529567 Hayes This symposium brings together experts in ecology, endocrinology, developmental biology, and molecular biology to address integrative studies on amphibian metamorphosis. Metamorphosis is one of the most remarkable biological processes described. During amphibian metamorphosis, one animal (the tadpole) virtually transforms into another (an adult frog). In addition to the obvious external changes, such as the resorption of the tail, the growth of limbs, and the beginning of terrestrial life, there are many other less obvious changes. Tadpoles are typically vegetarian whereas adults feed on insects or small animals, thus the structure of the gut and all of its enzymes change at metamorphosis; the immune system is destroyed and rebuilt to suit the frog; the gills resorb and are replaced by lungs; the structure of hemoglobin (the oxygen carrying molecule) changes; the structure and function of the eye transform from one that sees underwater to one better suited for seeing in air; the skin glands (which produce mucous, important antibiotics, and toxins) develop; the reproductive organs develop; etc. All of the changes in structures and functions are regulated by hormones. Although, thyroid hormone is the principal hormone stimulating these changes, other hormones such as prolactin and the stress hormone, corticosterone, modulate development. All of these hormones function by regulating genes, turning off the "tadpole genes" and turning on the "frog genes". In addition, these hormones are controlled by external factors such as temperature, food level, water quality, the presence of predators, and population density. Because of these complex interactions across levels of organization, environment-organism gene, metamorphosis is an excellent process for integrative studies. Amphibians can be used as a model to examine how environmental changes affect physiological processes as well as to examine gene regulation. Amphibian metamorphosis is a vital model for understanding development an d the role of genes in all vertebrates (including humans), because the developmental processes at metamorphosis can be observed directly (unlike embryonic development in other animals that typically occurs inside an egg or inside the mother). In addition, understanding changes in physiology and gene expression in response to environmental changes is vital in understanding how animals adapt to changes in environment. This understanding will result in better utilization of amphibians as indicators of environmental degradation, which is urgent given evidence for the recent global decline in amphibian populations.