Meeting Abstract

48.6  Tuesday, Jan. 5  Neurotransmitter functions in the placozoan Trichoplax adherens HEYLAND, Andreas*; GOODALL, Sophie; SOHN, Dosung; LEYS, Sally; MOROZ L., Leonid; University of Guelph, Department of Integrative Biology; University of Guelph, Department of Integrative Biology; The Whitney Laboratory for Marine Biosciences, University of Florida; The Whitney Laboratory for Marine Biosciences, University of Florida; University of Alberta, Biological Sciences aheyland@uoguelph.ca

Trichoplax adhaerens is an enigmatic disk-like animal consisting of only four morphologically identifiable cell types arranged into 3 layers – surface, middle and lower. The animal lacks anterior-posterior polarity, but shows distinct dorsal-ventral surfaces through intriguing righting behavior, and the presence of gland cells with digestive function in the ventral epithelium. In the absence of sufficient morphological characters its phylogenetic placement has long been controversial and recent molecular data have not been able to resolve the issue. The recently released genome reveals several genes coding for neurotransmitter synthesis enzymes and neuroendocrine signaling molecules. Thus the study of placozoans may provide insights into the early evolution of the nervous system. Using electron and light microscopy we characterized cell types by morphology, and we used histochemical markers for tubulin, actin and neuron-associated genes to identify cells with neuron-like properties. We also used cell cycle markers to identify regions of active cell division to identify the progenitors for each cell type. Studies to assess the involvement of specific cells in coordinating behaviours in the whole animal are in progress and will provide a better insight into how this basal animal functions.