| Two amylase genes, A and B, from the oyster Crassostrea gigas were characterized. Using PCR-RFLP, 6 and 4 alleles, respectively, were described for the amylase genes A and B. The roles of A and B amylase genes were investigated experimentally. They are expressed during larval and adult stages, and A transcripts are more abundant than B. The A transcript increases significantly with temperature, in high trophic conditions. However, A and B transcript levels do not change when food quantity increases although amylase activity augments. The level of B is correlated with dietary starch quantities, whereas the amount of A appears to remain constant ; simultaneously amylase activity decreases and the KM increases. These results suggest that expression of B is... |
