Evolutionary origins of coordination: Physiological and molecular studies on sponges

神经系统是如何进化的是进化生物学中一个经久不衰的问题。海绵是Porifera的成员，Porifera是最早的动物谱系之一；它们是滤食性动物，是仅有的两种缺乏神经系统的多细胞动物之一，但它们的基因组中有许多神经元型基因，并且海绵对环境刺激有一系列协调的行为。我和我的学生研究海绵如何协调行为，以了解感觉组织和协调系统如何产生神经元和神经系统。在这个节目中，我们解决三个问题：(1)“神经”分子是否在海绵组织中表达和使用感觉作用？(2)海绵的感觉协调是否使用了新的机制？(3)可能影响早期感觉系统进化的物理参数是什么？通过实验室和实地实验，我们将研究海绵中存在的基因、细胞和分子，它们共同作用产生全身行为。1)使用一种可以在实验室培养的海绵——它对刺激的反应是以一种看起来像打喷嚏的典型方式收缩——我们将使用药理学研究来测试信号是如何在组织中传播的。我们将探讨引起宫缩的触发因素和防止不必要的宫缩的触发因素，以实现协调的行为。我们还将绘制海绵组织图，以更好地了解哪些部分参与发送和接收导致收缩的信号。有可能动物进化出了非常不同的、不相关的协调身体的方法。我们将探索海绵体内的两个新的感觉系统，以更好地了解它们是否相当新颖，或者它们是否也保留了与动物树共享的根。其中一个系统是位于钙质海绵中的光感受器或海绵眼。另一种是海绵“鼻子”或组织瓣，覆盖吸入口，防止不需要的颗粒进入。我们将把这些结构中表达的基因和分子与其他动物感觉器官中的基因和分子进行比较。3)海绵如何反应，用什么细胞、组织和分子，需要了解海绵对什么做出反应。在第三条途径中，我们将研究海绵在其自然栖息地中对环境参数的反应范围。我们将测试食物、氧气、水流、光线或温度的变化是否会刺激未受干扰的海绵在其栖息地拍摄的收缩。我们还将测试特定参数对槽内海绵的影响。工作将主要在阿尔伯塔大学和西海岸海洋站班菲尔德海洋科学中心完成。

How nervous systems evolved is one of the enduring questions of evolutionary biology. Sponges are members of the Porifera, one of the earliest lineages of animals; they are filter feeders and are one of only two groups of multicellular animals that lack a nervous system, yet their genomes have many neuronal-type genes, and sponges have a range of coordinated behaviours in response to environmental stimuli. My students and I study how sponges coordinate behaviour to understand how sensory tissues and coordination systems may have given rise to neurons and nervous systems. In this program we address three questions: (1) Are `neural' molecules expressed and used in a sensory role in sponge tissues? (2) Are novel mechanisms used in sensory-coordination in sponges? and (3) What are the physical parameters that may have influenced early sensory system evolution? Using lab and field experiments we will study the genes, cells and molecules that exist in sponges and which work together to generate whole-body behaviours. 1) Using a sponge that can be grown in the lab - and which responds to stimuli by contracting in a stereotypical way that looks like a sneeze - we will use pharmacological studies to test how signals propagate across tissues. We will explore the triggers that cause contractions and those that prevent unwanted contractions to allow a coordinated behaviour. We will also map the sponge's tissues to better understand which parts are involved in sending and receiving the signals that cause contractions. 2) It is possible that animals evolved very different, unrelated, methods of coordinating their bodies. We will explore two new sensory systems in the sponge body to better understand whether these are quite novel, or whether they also retain roots shared with the animal tree. One such system is a photoreceptor or sponge eye, in a calcarous sponge. The other is a sponge 'nose' or flap of tissue that covers the inhalent openings preventing entry of unwanted particles. We will compare genes and molecules expressed in these structures with those in sensory organs in other animals. 3) How sponges respond and with what cells, tissues, and molecules, requires understanding what sponges respond to. In a third avenue we will investigate the range of environmental parameters that sponges respond to in their natural habitats. We will test whether presence or absence of food, oxygen, flow, light, or changes in temperature stimulate contractions in undisturbed sponges filmed in their habitat. We will also test the effect of specific parameters on sponges in tanks. Work will mostly be done at the University of Alberta, and at the west coast marine station, the Bamfield Marine Sciences Centre.