Evolutionary origins of coordination: Physiological and molecular studies on sponges (Porifera)

海绵是现存最原始的动物Porifera的成员。海绵是滤食性动物，是唯一一组没有神经系统的多细胞动物，但它们有各种各样的缓慢行为，使它们能够防止堵塞过滤器。海绵的第一个基因组现在是可用的，其中有许多我们在其他动物的神经系统中看到的分子。我和我的学生们研究海绵前神经系统，以了解第一个神经系统是如何进化的。我们对海绵如何感知环境的变化以及它们如何协调全身反应感兴趣。该提案将研究a)参与海绵细胞间信号传递的分子，以及细胞上可接收信号的受体；B)海绵在过滤系统中定位感觉细胞的分子机制；c)引导海绵体形成的流体流动物理参数。将海绵中发现的基因与有神经系统的动物的基因进行比较，突显出即使没有传统神经，动物的信号传导方式也存在显著的相似性。我们提出的研究计划侧重于确定细胞之间发生信号传导的区域（是否存在“原突触”？），并最终确定在发育中和成年海绵中产生感觉和信号传递的新细胞的位置。

Sponges are members of the Porifera, the most primitive extant animals. Sponges are filter feeders and are the only group of multicellular animals without a nervous system, yet they have various types of slow behaviour that allow them to prevent clogging the filter. The first genome of a sponge is now available, and in it are many molecules that we see in nervous systems in other animals. My students and I study the sponge pre-nervous systems to understand how the first nervous systems might have evolved. We are interested in how sponges sense changes in their environment and how they coordinate whole body responses. This proposal will investigate a) the molecules involved in signaling between cells in the sponge, and the receptors available to receive signals on cells; b) the molecular mechanisms that sponges use to position sensory cells in the filtration system; and c) the physical parameters of fluid flow that guide the formation of the sponge body. Comparing genes found in sponges with those in animals that have nervous systems has highlighted remarkable similarities in the way signaling works in animals even without conventional nerves. Our proposed research program focuses on identifying the regions where signaling occurs between cells (is there a ‘proto-synapse’?) and ultimately determining where new cells involved in sensation and transmission of signals are produced in developing and in adult sponges.