Crustin expression following bacterial injection and temperature change in the shore crab, Carcinus maenas

SummaryThe expression of carcinin, a crustin-type antimicrobial protein, in the crab, Carcinus maenas, was studied following in vivo challenge with Planococcus citreus, a Gram-positive bacterium known to be killed by the encoded protein. Real-time PCR analyses reveal that injection of P. citreus failed to elicit any significant changes in expression at 0–24 h post-injection although there was a small, but significant, down-regulation at 84 h in crabs held at 15 °C but not those at 5 or 20 °C. By contrast, un-injected crabs held at various temperatures between 5 and 20 °C, showed significantly up-regulated expression at 5 and at 20 but not 10 °C compared with controls at 15 °C. Thus expression of carcinin seems to be affected by temperature, especially when the animal is close to the edges of its physiologically tolerated thermal range.