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Environmental Rearing Conditions Produce Forebrain Differences In Wild Chinook Salmon Oncorhynchus Tshawytscha, R. L. Kihslinger, Sean C. Lema, G. A. Nevitt
Environmental Rearing Conditions Produce Forebrain Differences In Wild Chinook Salmon Oncorhynchus Tshawytscha, R. L. Kihslinger, Sean C. Lema, G. A. Nevitt
Biological Sciences
Recent studies suggest that hatchery-reared fish can have smaller brain-to-body size ratios than wild fish. It is unclear, however, whether these differences are due to artificial selection or instead reflect differences in rearing environment during development. Here we explore how rearing conditions influence the development of two forebrain structures, the olfactory bulb and the telencephalon, in juvenile Chinook salmon (Oncorhynchus tshawytscha) spawned from wild-caught adults. First, we compared the sizes of the olfactory bulb and telencephalon between salmon reared in a wild stream vs. a conventional hatchery. We next compared the sizes of forebrain structures between fish reared …
Evidence That Thyroid Hormone Induces Olfactory Cellular Proliferation In Salmon During A Sensitive Period For Imprinting, Sean C. Lema, Gabrielle A. Nevitt
Evidence That Thyroid Hormone Induces Olfactory Cellular Proliferation In Salmon During A Sensitive Period For Imprinting, Sean C. Lema, Gabrielle A. Nevitt
Biological Sciences
Salmon have long been known to imprint and home to natal stream odors, yet the mechanisms driving olfactory imprinting remain obscure. The timing of imprinting is associated with elevations in plasma thyroid hormone levels, with possible effects on growth and proliferation of the peripheral olfactory system. Here, we begin to test this idea by determining whether experimentally elevated plasma levels of 3,5,3′-triiodothyronine (T3) influence cell proliferation as detected by the 5-bromo-2′-deoxyuridine (BrdU) cell birth-dating technique in the olfactory epithelium of juvenile coho salmon (Oncorhynchus kisutch). We also explore how natural fluctuations in thyroxine (T4) …
Phenotype Management: A New Approach To Habitat Restoration, Jason V. Watters, Sean C. Lema, Gabrielle A. Nevitt
Phenotype Management: A New Approach To Habitat Restoration, Jason V. Watters, Sean C. Lema, Gabrielle A. Nevitt
Biological Sciences
The goal of habitat restoration is to provide environmental conditions that promote the maintenance and growth of target populations. But rarely is it considered how the allocation of resources influences the diversity of phenotypes in these populations. Here we present a framework for considering how habitat restoration can shape the development and expression of phenotypes. We call this approach phenotype management as it entails restoring the resources in a habitat to manage phenotypic diversity. Phenotype management is achieved by manipulating the spatial and temporal distribution of resources to alter the degree of competition among individuals. Differences in competition, in turn, …
Re-Evaluating Nadph-Diaphorase Histochemistry As An Indicator Of Nitric Oxide Synthase: An Examination Of The Olfactory System Of Coho Salmon (Oncorhynchus Kisutch), Sean C. Lema, Gabrielle A. Nevitt
Re-Evaluating Nadph-Diaphorase Histochemistry As An Indicator Of Nitric Oxide Synthase: An Examination Of The Olfactory System Of Coho Salmon (Oncorhynchus Kisutch), Sean C. Lema, Gabrielle A. Nevitt
Biological Sciences
The NADPH-diaphorase (NADPH-d) histochemical technique is commonly used to localize the nitric oxide (NO)-producing enzyme NO synthase (NOS) in neural tissues. In the olfactory tissues of vertebrates, however, NADPH-d staining can be present without the detection of NOS by other methods. We used pharmacological controls to determine whether NADPH-d staining was indicative of NOS in olfactory tissues from coho salmon (Oncorhynchus kisutch). We also compared NADPH-d staining with immunoreactivity to NOS. NADPH-d staining localized to the olfactory epithelium and to the glomerular layer of the olfactory bulb. Two NOS inhibitors, L-N-nitroarginine and L-N-methyl-L-arginine, failed …