Starvation-induced social behavior in C. elegans

描述（由申请人提供）：有些动物生活在一起，在稳定的群体，而其他人喜欢一个孤独的生活方式。但即使是最不合群的生物，在某些环境条件下也可能表现出聚集在一起的倾向。它们可能在不同的情况下和出于各种原因这样做，但所有这些都可以从统一的进化角度来考虑。例如，评估环境并预测未来环境将如何变化的能力对于动物生存和最大化适应性至关重要。一 一种获得更完整的环境表示的方法是整合其他人传达的信息。遗传上易处理的线虫秀丽隐杆线虫（Caushabditis elegans）的整个神经由302个神经元组成，是探索动物在社会背景下决策的神经发生机制的一个有吸引力的系统。 本文的研究对象是最近发现的C. elegans L1幼虫饥饿诱导的聚集，这导致提高生存。初步结果表明，聚集需要至少两个功能性化学感觉神经元，称为ASE和ASH，并且可能由蠕虫衍生的化学信号介导。我们确定了一种产生聚集信号所必需的酶--醇脱氢酶SODH-1。提高饥饿存活率的幼虫在集群点的功能重要性的聚集C。优雅健身 概括地说，这个项目的目标是了解个体的神经元，遗传和分子机制如何促成一个新兴的群体行为，聚集。在个体水平上，我们想知道蠕虫的交换信号是什么，蠕虫中的哪些神经元对这些信号做出反应，以及这些神经元中激活了哪些信号通路。这些问题将通过LC-MS和NMR化学分析和传统分子遗传学的工具进行实验解决。在种群水平上，我们想知道动物是如何聚集在一起并聚集在一起的，是什么决定了这些聚集体的大小和形状，更重要的是，这种行为对蠕虫的适应性有什么好处。为此，我们将使用主动步行者模型计算探索聚合，增强以评估聚合对信息准确性和适应性的贡献。数学建模将与蠕虫行为的实验定量跟踪密切相关。该提案的具体目标是-目标1：确定饥饿诱导的L1聚集的神经元和遗传机制。目的2：描述介导L1相互作用的信号。目标3：建立一个L1聚合和适应度的数学模型。而在C.虽然线虫可能是物种特异性的，但社会互动在做出关键决策中的作用是一个更广泛的问题。了解社会背景下决策过程的深层进化根源，在人类社会中最终导致有害或有益的社会行为，可能有助于改善我们的生活方式和心理健康。

DESCRIPTION (provided by applicant): Some animals live together in stable groups while others prefer a solitary life style. But even the most asocial creatures may show a propensity to come together and aggregate under some environmental conditions. They may do so in different circumstances and for various reasons, yet all of them can be considered from a unifying evolutionary perspective. For instance, the ability to assess the environment and predict how it is going to change in the future is critical for animal survival and maximizing fitness. One way to obtain a more complete representation of the environment is to integrate information communicated by others. The genetically tractable nematode Caenorhabditis elegans, whose entire nervous consists of 302 neurons, is an attractive system for exploring neurogenetic mechanisms of animal decision-making in social contexts. The subject of this proposal is a recently discovered collective behavior of C. elegans L1 larvae-starvation- induced aggregation, which leads to improved survival. Preliminary results show that the aggregation requires at least two functional chemosensory neurons, called ASE and ASH, and is likely mediated by worm-derived chemical signals. We identified an enzyme essential for producing the aggregation signal-the alcohol dehy- drogenase SODH-1. Improved starvation survival of the larvae in clumps points to the functional importance of the aggregation for C. elegans fitness. Broadly, the goal of this project is to understand how neuronal, genetic, and molecular mechanisms in an individual contribute to an emergent population behavior, aggregation. At the individual level we want to know what signals the worm's exchange, what neurons in the worm respond to these signals, and what signaling pathways are activated in these neurons. These questions will be addressed experimentally with the tools of LC-MS and NMR chemical analysis and traditional molecular genetics. At the population level we want to know how animals come together and stay in clumps, what determines size and shape of these aggregates, and more importantly, what fitness benefits this behavior has for the worms. To this end we will computationally explore the aggregation using the active walker model, augmented to evaluate the contribution of aggregation to information accuracy and fitness. Mathematical modeling will be closely paralleled with experimental quantitative tracking of worm behavior. Specific aims of the proposal are - Aim 1: Determine neuronal and genetic mechanisms of starvation-induced L1 aggregation. Aim 2: Characterize the signals that mediate the L1 inter- actions. Aim 3: Develop a mathematical model for L1 aggregation and fitness. While the exact molecular mechanisms that operate in C. elegans may be species-specific, the role of social interactions in making critical decisions is a far broader question. Understanding the deep evolutionary roots of decision-making processes in social contexts, which in human society eventually lead to harmful or beneficial social behaviors, may help to improve our life style and mental health.