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Restricted Access Thesis
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Central Pattern Generators (CPGs), networks of neurons that control rhythmic motor outputs such as breathing and walking, can be modulated to yield different motor outputs for the same muscular system. The lobster, Homarus americanus, has a neurogenic heart controlled by the cardiac ganglion (CG), a prime model for studying CPGs. When a lobster heart is perfused with the neuropeptide Allatostatin-C (AST-C ), contraction amplitude either increases or decreases depending upon the lobster. It was hypothesized that the lobsters’ differential responses to AST-C are due to differential expression and/or distribution of AST-C receptors in the CG, and that these receptors are well conserved in decapods. This study aims to characterize AST-C peptides and receptors within crustaceans. RNA sequencing of H. americanus pooled nervous system tissues produced a transcriptome database that was mined for AST-C peptides and receptors. Three isoforms of AST-C peptide and AST-C receptors were identified from the transcriptome. Phylogenetic analyses of AST-C peptides and receptors showed that both are well conserved for most crustaceans. These putative receptors were confirmed in lobster tissues using RT-PCR tissue profiling techniques for CG, heart muscle, brain, eyestalk, and midgut of the lobster. Results indicate that AST-C peptides and receptors are endogenous to the lobster. The receptors were sequenced from lobster brain tissue using RT-PCR. AST-C receptor sequences from RT-PCR were 100% identical to the AST-C receptor sequences identified via transcriptomics, though RT-PCR sequencing did not sequence any entire AST-C receptor.
Available for download on Saturday, September 25, 2021