Phenoloxidase Is an Important Component of the Defense against Aeromonas hydrophila Infection in a Crustacean, Pacifastacus leniusculus

作者：Haipeng Liu, Pikul Jiravanichpaisal, Lage Cerenius, Bok Luel Lee, Irene Söderhäll, Kenneth Söderhäll · 发表于：Journal of Biological Chemistry · 年份：2007 · DOI：10.1074/jbc.m706113200 · 被引用次数：248 · 研究领域：Invertebrate Immune Response Mechanisms、Aquaculture disease management and microbiota、Insect symbiosis and bacterial influences

The melanization cascade, in which phenoloxidase is the terminal enzyme, appears to play a key role in recognition of and defense against microbial infections in invertebrates. Here, we show that phenoloxidase activity and melanization are important for the immune defense toward a highly pathogenic bacterium, Aeromonas hydrophila, in the freshwater crayfish, Pacifastacus leniusculus. RNA interference-mediated depletion of crayfish prophenoloxidase leads to increased bacterial growth, lower phagocytosis, lower phenoloxidase activity, lower nodule formation, and higher mortality when infected with this bacterium. In contrast, if RNA interference of pacifastin, an inhibitor of the crayfish prophenoloxidase activation cascade, is performed, it results in lower bacterial growth, increased phagocytosis, increased nodule formation, higher phenoloxidase activity, and delayed mortality. Our data therefore suggest that phenoloxidase is required in crayfish defense against an infection by A. hydrophila, a highly virulent and pathogenic bacterium to crayfish.