Adaptive Plasticity of Fish Locomotory Muscle

鱼类的运动肌具有非凡的能力来改变它们的生化、生理和性能特征，以响应个体发育、生理和环境的影响。索梅罗博士和他的同事们将通过实验修改白色和红色肌肉的生化特性，以便在生化状态和运动能力之间建立更清晰的联系。他们将通过改变饮食方案来改变肌肉的生化状态，然后定量测定酶活性和游泳成绩。他们将确定转录和翻译活性以及蛋白质周转的变化如何确定ATP生成酶的最终浓度。他们将以不同的强度让鱼游泳，并测量酶在细胞内的定位--分区--如何变化。同时还将测量影响酶区划的pH值和效应物。身体大小会影响肌肉中ATP生成酶的水平和调节机制，并将进行评估。将使用量化RNA浓度和测量蛋白质合成和蛋白质降解的技术来研究导致这些大小依赖(“比例”)变化的调控机制。深海鱼类将保留在实验室中，以确定这些鱼类的代谢率和游泳能力大幅下降的程度，一方面是内在的、基于遗传的因素，另一方面是饮食因素。他们将试图在这些深海生物形式中将肌肉的生化健壮性(例如，酶水平和RNA浓度)提高到可能的最高水平，以确定它们最终的活动和增长潜力。目标是了解鱼类运动能力变化的生化和生理基础。

The locomotory muscles of fishes have an extraordinary ability to alter their biochemical, physiological, and performance characteristics in response to ontogenetic, physiological, and environmental influences. Dr. Somero and his colleagues will experimentally modify the biochemical properties of white- and red muscles to establish clearer links between biochemical status and locomotory capacity. They will vary muscle biochemical state through altered dietary regimen and, then, quantitate enzymatic activities and swimming performance. They will determine how variations in transcriptional and translational activity and in protein turnover establish final concentrations of ATP generating enzymes. They will swim fishes at different intensities and measure how the intracellular localization--the compartmentalization-- of enzymes varies. Measurements of pH and of effectors that influence enzyme compartmentalization will be made concomitantly. Body size influences the levels of ATP generating enzymes in muscle and the regulatory mechanisms and will be evaluated. The regulatory mechanisms responsible for these size-dependent ("scaling") changes will be studied using techniques to quantify RNA concentrations and to measure protein synthesis and protein degradation. Deep-sea fish will be maintained in the laboratory to determine the extent to which the greatly reduced metabolic rates and swimming capabilites of these fishes are due to intrinsic, genetically-based factors, on the one hand, and dietary factors, on the other. They will attempt to bring the muscle biochemical robustness (e.g., enzyme levels and RNA concentrations) to the highest possible levels in these deep-living forms to establish their ultimate potential for activity and growth. The goal is an understanding of the biochemical and physiological basis for variations in locomotor capacity in fish.