In temperate ecosystems, most benthic communities exhibit between-year variability in the seasonal appearance and abundance of their opportunistic members. It seems likely that the life-history strategies of these organisms directly regulates their growth and reproduction. This may result form annual differences in the availability of dietary micronutrients. Opportunistic, deposit-feeding polychaetes face a unique nutritional constraint: their small body size limits the amount of assimilated materials they can store. They are dependent on the immediate availabilities of their dietary requirements to fuel their growth and reproduction. Although growth and reproduction in opportunists in stimulated by food supply, little is known about the dietary components that regulate how much and how fast an opportunist can grow. This project will assess the potential for two micronutrients (vitamin D and the carotenoid, B-Carotene) to stimulate somatic cell divisions at the gene transcription level in the polycheate worm, Streblospio benedicti. The C-myc protooncogne will be used to assay tissue responses to dietary composition immediately (0-24h) after feeding. Quantifying c- myc mRNA transcript levels will provide an instantaneous snapshot of cell division activity in a tissue sample. Relating tissue responses to a life-history pattern of rapid growth and reproduction will primarily focus on evaluating the potential for vitamin D or B-carotene to initiate and maintain mitotic cycling independent of dietary composition.
