Meeting Abstract
68.1 Sunday, Jan. 6 The effect of dietary copper on coelomocyte populations in the sea urchin Lytechinus variegates POWELL, M/L*; GHANTA, V; JENNINGS, N; GARRIS, H; NELSON, A; LAWRENCE, A/L; WATTS, S/A; Univ. of Ala., B’ham; Univ. of Ala., B’ham; Univ. of Ala., B’ham; Univ. of Ala., B’ham; Univ. of Ala., B’ham; Texas A&M, Port Aransas; Univ. of Ala., B’ham mpowell@uab.edu
The innate immune system of sea urchins is composed in part of coelomocytes circulating free in the coelom. These cells respond to pathogens and environmental stress through changes in cell number and type. It is not known how dietary nutrients affect the sea urchin immune system. Copper(Cu) is an essential micronutrient in the diets of most animals. It is a component of many enzymes involved in energy production and in the protection of cells from free radical induced change. Excess levels in the diet can be toxic, however, the effect of sublethal levels is more difficult to quantify. L. variegates were fed formulated feeds with 6, 50, or 159 ppm Cu (levels based on established dietary levels for other marine invertebrates, supplemented as CuSO4) or the standard EPA maintenance diet of organic lettuce and carrots for 16 weeks. Coelomic fluid (100 ul) was removed and mixed 1:1 (V:V) with 10% EDTA in sterile artificial seawater. Total cell number and type of coelomocytes were determined by differential cell counts (n=8 individuals per treatment). The total number of coelomocytes was significantly lower for L. variegates fed lettuce and carrots (4.33×106 cells/mL) when compared to all of the Cu diets (p = 0.023). Total coelomocytes were significantly lower (p = 0.049) in the 159 ppm Cu diet (5.29×106 cells/mL) compared to the 6 ppm Cu diet (6.56×106 cells/mL). The consequence of lower numbers of coelomocytes is not clear; however, we hypothesize that decreased coelomocyte numbers may result in a reduced ability to respond to environmental pathogens or stress. Supported in part by the Mississippi-Alabama Sea Grant Consortium and NSF ADVANCE.
