An integrated approach to stress in fish: behaviour, molecular biology and physiology

我的研究项目的长期目标集中在整合鱼类的生理和行为，以及了解鱼类的气体转移和酸碱调节策略。虽然这两个目标表面上看起来完全不同，但实际上它们是由应激反应、皮质醇、酸碱和离子调节、碳酸酐酶（CA）和二氧化碳排泄等统一主题联系在一起的。在整合生理和行为方面，我们使用虹鳟鱼的社会等级来研究社会地位的生理原因和后果。基于这一领域的最新进展，我们关注了低社会地位的直接生理成本，包括生长抑郁、低氧耐受性降低以及慢性社会压力对急性应激反应的影响，我现在建议确定社会诱导的生长抑郁的生理机制，并研究低社会地位对离子调节和酸碱平衡的影响。这项工作的目的是提高我们对支撑行为的生理机制的理解，但所获得的信息在应用环境中也很重要，例如预测污染物对鱼类种群的影响，或为水产养殖设计有效的畜牧业实践。关于了解鱼类气体传递和酸碱调节策略的长期目标，我的目标是建立在我们最近在鉴定鱼类CAs的分子结构和功能方面的进展。CA是一种几乎无处不在的酶，它催化二氧化碳反应，因此有助于从二氧化碳排泄和酸碱平衡到新陈代谢的生理过程。我建议探索从肺鱼中克隆的一组CA异构体的生理作用，以研究酸碱干扰对CA表达的调节，并在斑马鱼中鉴定缺氧诱导的CA异构体。通过对鱼类CA同工异构体及其功能的新认识，本研究将增加我们对鱼类气体传递和酸碱调节的认识，以及对脊椎动物CA基因家族进化的认识。

The long-term objectives of my research program focus on integrating physiology and behaviour in fish, and on understanding piscine strategies for gas transfer and acid-base regulation.  While these two objectives appear superficially to be quite disparate, they are in fact linked by such unifying themes as stress responses, cortisol, acid-base and ionic regulation, the enzyme carbonic anhydrase (CA), and CO2 excretion.      In terms of integrating physiology and behaviour, we use social hierarchies in rainbow trout to examine the physiological causes and consequences of social status.  Building on recent progress in this area, in which we have focused on the immediate physiological costs of low social status, including growth depression, reduced tolerance of low O2 and the impact of chronic social stress on acute stress responses, I now propose to identify the physiological mechanisms underlying socially-induced growth depression and investigate the impact of low social status on ionic regulation and acid-base balance.  The aim of this work is to improve our understanding of the physiological mechanisms underpinning behaviour, but the information gained can also be important in an applied setting, for example in predicting the impact of pollutants on fish populations, or in designing effective animal husbandry practices for aquaculture.    With respect to the long-term goal of understanding strategies for gas transfer and acid-base regulation in fish, I aim to build on our recent progress in identifying the molecular structure and function of fish CAs.  CA is a near-ubiquitous enzyme that catalyzes CO2 reactions and hence contributes to physiological processes ranging from CO2 excretion and acid-base balance to metabolism.  I propose to explore the physiological roles of a group of CA isoforms that we cloned from lungfish, to examine the regulation of CA expression during acid-base disturbances, and to identify hypoxia-inducible CA isoforms in zebrafish.  By generating new information on CA isoforms in fish and their functions, this work will increase our understanding both of gas transfer and acid-base regulation in fish, and of the evolution of the CA gene family in vertebrates.