BackgroundAnimal responses to thermal stimuli involve intricate contributions of genetics, neurobiology and physiology, with temperature variation providing a pervasive environmental factor for natural selection. Thermal behavior thus exemplifies a dynamic trait that requires non-trivial phenotypic summaries to appropriately capture the trait in response to a changing environment. To characterize the deterministic and plastic components of thermal responses, we developed a novel micro-droplet assay of nematode behavior that permits information-dense summaries of dynamic behavioral phenotypes as reaction norms in response to increasing temperature (thermal tolerance curves, TTC).ResultsWe found that C. elegans TTCs shift predictably with rearing conditions and developmental stage, with significant differences between distinct wildtype genetic backgrounds. Moreover, after screening TTCs for 58 C. elegans genetic mutant strains, we determined that genes affecting thermosensation, including cmk-1 and tax-4, potentially play important roles in the behavioral control of locomotion at high temperature, implicating neural decision-making in TTC shape rather than just generalized physiological limits. However, expression of the transient receptor potential ion channel TRPA-1 in the nervous system is not sufficient to rescue rearing-dependent plasticity in TTCs conferred by normal expression of this gene, indicating instead a role for intestinal signaling involving TRPA-1 in the adaptive plasticity of thermal performance.ConclusionsThese results implicate nervous system and non-nervous system contributions to behavior, in addition to basic cellular physiology, as key mediators of evolutionary responses to selection from temperature variation in nature.

中文翻译：

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秀丽隐杆线虫行为热耐受的神经遗传可塑性

背景动物对热刺激的反应涉及遗传学、神经生物学和生理学的复杂贡献，温度变化为自然选择提供了普遍的环境因素。因此，热行为体现了一种动态特征，需要非平凡的表型摘要来适当地捕捉特征以响应不断变化的环境。为了表征热响应的确定性和可塑性成分，我们开发了一种线虫行为的新型微液滴测定法，允许将动态行为表型的信息密集摘要作为响应于温度升高的反应规范（热耐受曲线，TTC）。结果我们发现秀丽隐杆线虫 TTC 随饲养条件和发育阶段而发生可预测的变化，不同的野生型遗传背景之间存在显着差异。此外，在筛选 58 C. elegans 遗传突变株的 TTC 后，我们确定影响热感觉的基因，包括 cmk-1 和 tax-4，可能在高温下运动的行为控制中发挥重要作用，暗示神经决策TTC 形状而不仅仅是广义的生理限制。然而，神经系统中瞬时受体电位离子通道 TRPA-1 的表达不足以挽救 TTC 中由该基因正常表达赋予的饲养依赖性可塑性，相反表明涉及 TRPA-1 的肠道信号传导在适应性热性能的可塑性。结论这些结果暗示神经系统和非神经系统对行为的贡献，