| Summary: | This thesis explores the feasibility of using melanophore-based
biosensors from Oreochromis niloticus. Melanophores are one type of
pigmented cell of the scales and fins of fish that respond in a motile fashion to a
diverse range of stimuli. Fish scales were employed as the first step in
determining the utility of melanophores as biosensors. Responsiveness of
melanophores in scales was quantitated with several bioactive agents.
Experiments with depolarizing potassium ion, guanethidine, yohimbine (an
adrenergic antagonist), and capsaicin (a sensory stimulant) provided evidence
that melanophores are under nervous regulation.
Conditions were developed to allow simplification of intact scale
preparations, entailing epidermal removal and dennervation of scales. This
simplification resulted in increased sensitivity and responsiveness to a larger
array of bioactive agents, including a cyclic AMP analog. The simplified
preparation was successfully tested for its ability to function as a biosensor
using pharmaceutical eye drops; the response observed was determined to be due to naphazoline, an adrenergic agonist. Methods were developed that enabled culturing of chromatophores independent from scales. Cultured chromatophores were found to be responsive to bioactive agents with a comparable degree of sensitivity as simplified scale preparations. Attempts were undertaken to develop co-cultures of chromatophores with other cell types and with further development melanophore-based biosensors can be exploited. === Graduation date: 1997
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