Starvation-induced social behavior in C. elegans

描述(申请人提供)：一些动物群居在一起，而另一些动物喜欢独居生活。但即使是最不合群的生物也可能在某些环境条件下表现出聚集和聚集的倾向。它们可能在不同的情况下，出于不同的原因这样做，但它们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健康至关重要。一 获得更完整的环境表示的方法是整合其他人交流的信息。秀丽线虫是一种遗传易驯化的线虫，其整个神经由302个神经元组成，是探索社会背景下动物决策的神经遗传学机制的一个有吸引力的系统。这项建议的主题是最近发现的线虫L1幼虫的集体行为-饥饿诱导聚集，从而提高存活率。初步结果表明，这种聚集至少需要两个功能良好的化学感觉神经元，称为ASE和ASH，可能是由蠕虫衍生的化学信号介导的。我们鉴定了一种产生聚集信号所必需的酶--乙醇脱氢酶SODH-1。丛生幼虫饥饿存活率的提高表明聚集对线虫适合度的功能重要性。从广义上讲，这个项目的目标是了解个体中的神经元、遗传和分子机制如何促成一种新的群体行为--聚集。在个体层面上，我们想知道蠕虫交换的信号是什么，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。这些问题将用LC-MS和核磁共振化学分析和传统分子遗传学的工具进行实验研究。在种群水平上，我们想知道动物是如何聚集在一起并呆在一起的，是什么决定了这些聚集体的大小和形状，更重要的是，这种行为对蠕虫的健康有什么好处。为此，我们将使用主动步行者模型对聚合进行计算探索，并对该模型进行扩展，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。目标2：描述调节L1相互作用的信号。目的3：建立L1聚集和适应度的数学模型。虽然在线虫体内运作的确切分子机制可能是特定于物种的，但社会互动在做出关键决定方面的作用是一个更广泛的问题。了解决策过程在社会背景下的深层进化根源，人类社会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.