Graduation Date
Spring 2024
Document Type
Thesis
Program
Master of Science degree with a major in Biology
Committee Chair Name
Karen Kiemnec-Tyburczy
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
John Reiss
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Sharyn Marks
Third Committee Member Affiliation
HSU Faculty or Staff
Fourth Committee Member Name
Amy Sprowles
Fourth Committee Member Affiliation
HSU Faculty or Staff
Keywords
Olfaction, Plethodontid, Salamander, Life stage, Desmognathus
Subject Categories
Biology
Abstract
The olfactory system of extant amphibians changes as the animal transitions from a fully aquatic to a terrestrial lifestyle at metamorphosis. Cellular morphology of the nose and expression patterns of olfactory genes in the nasal cavity have been examined for a variety of frogs and salamanders, but among plethodontid salamanders, molecular data are available only for Plethodon shermani. Using standard histology and micro-CT reconstruction, I investigated the structure of the olfactory organs of larvae, juveniles, and adults of six plethodontid species, with terrestrial, streamside, semiaquatic, and aquatic adults. The overall structure of the olfactory cavity was generally similar across species, but in Desmognathus aureatus, there was a great change in shape of the organ before and after metamorphosis, with a reduction of the epithelium not reported in other plethodontids. At the molecular level, I used in situ hybridization to localize the expression of three G proteins (Gαolf, Gαo and Gαi2) and one cation channel (TRPC2). The expression of all the olfactory components did not vary between the juvenile and the adult life stages in terrestrial plethodontids. Generally, the main olfactory cavity expressed Gαolf, the vomeronasal organ (VNO) expressed TRPC2, and Gαo was expressed in the whole iii cavity. Expression of Gαolf in the VNO is absent in larvae but occurs in adults of some species. In direct-developing species, TRPC2 is restricted to the VNO, while some biphasic species express it in the whole cavity. Thus, TRPC2 appears to have a crucial role in chemoreception in all life stages and species.
Citation Style
MLA
Recommended Citation
Lanzilli, Giuseppina S., "Comparing alternative developmental modes: Structure and gene expression in the olfactory system of Plethodontid salamanders" (2024). Cal Poly Humboldt theses and projects. 722.
https://digitalcommons.humboldt.edu/etd/722
Collaboration
1