Ionotropic Receptor and Neuropeptide Expression in Chemosensory Appendages of the Berghia nudibranch

Presenter

Gianna Francesca Misuraca

Campus

UMass Amherst

Sponsor

Paul Katz, Department of Biology, UMass Amherst

Schedule

Session 4, 2:30 PM - 3:15 PM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board A18, Campus Center Auditorium, Row 1 (A1-A20) [Poster Location Map]

Abstract

The molecular basis of chemosensation is relatively unknown in molluscs compared to other taxa. It was recently shown that the chemosensory ionotropic receptors (IRs) of insects are ancient across protostomes. Neuropeptides also play roles in the sensory periphery across invertebrates. We investigated the intersection of these molecular systems in the chemosensory appendages of the nudibranch mollusc Berghia stephanieae. We predicted that the rhinophores (distance chemosensation) and oral tentacles (contact chemosensation) would exhibit different patterns of gene expression. Two putative chemosensory IRs as well as the molluscan neuropeptides APGWamide and FCAP (feeding circuit activating peptide) were identified from brain transcriptomes. In-situ hybridization chain reaction (HCR) for the four genes showed that in the rhinophore, APGWamide-expressing cells were the most abundant, with IR-D restricted to cells only at the base of the appendage. FCAP and IR25A showed significant coexpression in an intermediate number of rhinophore cells. In the oral tentacle, there were fewer IR25A, FCAP, and APGWamide expressing cells, and more IR-D expressing cells than in the rhinophore. In conclusion, labeling with a mere four molecular markers revealed complex, differential patterns of expression between the rhinophores and oral tentacles of Berghia. Each appendage likely contains an even wider diversity of sensory neuron types that will be revealed as we use additional receptor and peptide markers. This diversity of cell types suggests a similar diversity in function.

Keywords

Chemosensation, Neuropeptides, Sea slugs, HCR, Ionotropic receptors

Research Area

Biological Organisms

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