Ecological and Evolutionary Physiology of the Stress Response and Stress Proteins

生态和进化生理学的一个主要问题是复杂生物体的特性、生物体利用不同环境的能力和物种在时间上的持久性之间的关系。本研究旨在研究果蝇热休克蛋白Hsp70以解决这一问题。在对热或其他胁迫的反应中，几乎所有的生物都表达热休克蛋白（Hsps），这是一种高度保守的蛋白，通过充当分子伴侣来促进应激耐受性。一项由美国国家科学基金会（NSF）先前奖励支持的研究已经证实，通过实验操纵果蝇的hsp70基因拷贝数，足以引起耐热性的变化。本研究将以这一发现为基础，探讨在少数其他系统中可能同时解决的三个相关问题：(1)Hsp70功能的生理机制；即热应力如何破坏功能，以及Hsp70如何防止热损伤或帮助恢复。这个问题将在果蝇的幼虫肠道中进行研究，果蝇的幼虫肠道特别容易受到热损伤。(2) Hsp70表达的适应度结果，将通过比较不同Hsp70表达的果蝇菌株在自然热应激下的存活率和后代产量来检验。(3) Hsp70基因变异的进化基础，将通过测定自然种群和实验种群中Hsp70基因的表达、拷贝数和温度阈值来检验Hsp70基因变异的进化基础。为了实现这些目标，拟议的研究将检查果蝇的基因工程和自然变异。该研究的预期结果具有巨大的潜力，可以整合分子、遗传、功能和进化的观点，以促进对适应的理解。

Feder 9723298 A major issue in ecological and evolutionary physiology is the relationship among the traits of complex organisms, organisms' ability to exploit diverse environments, and species' persistence in time. The proposed investigation examines the heat-shock protein Hsp70 in Drosophila to address this issue. In response to heat or other stresses, nearly all organisms express heat-shock proteins (Hsps), highly-conserved proteins that contribute to stress tolerance by functioning as molecular chaperones. Research supported by a previous NSF award has established that experimental manipulation of copy number of the hsp70 gene of Drosophila, which encodes Hsp70, is sufficient to cause changes in thermotolerance. The proposed research will build upon this finding to examine three related issues whose simultaneous resolution is possible in few other systems: (1) The physiological mechanism of Hsp70 function; i.e., how thermal stress disrupts function and how Hsp70 protects against heat damage or aids recovery from it. This issue will be examined in the larval gut of Drosophila, which is especially susceptible to heat damage. (2) The fitness consequences of Hsp70 expression, which will be examined by comparing survival and offspring production when Drosophila strains differing in Hsp70 expression are exposed to natural thermal stress. (3) The evolutionary basis for variation in Hsp70, which will be examined by measuring Hsp70 expression, hsp70 copy number, and the temperature threshold for Hsp70 expression in natural and experimental populations. To accomplish these goals, the proposed research will examine genetically engineered and natural variation in Drosophila. The projected outcome of the proposed research has immense potential to integrate molecular, genetic, functional, and evolutionary perspectives to advance understanding of adaptation.