title: Phenoloxidase is an important component of the defense against Aeromonas hydrophila Infection in a crustacean, Pacifastacus leniusculus.
abstract: 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.
authors.affiliation: Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.
authors.forename: Haipeng
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden; Molecular Aquatic Biology and Genetic Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 73/1 Rama VI Road, Rajdhevee, Bangkok 10400, Thailand.
authors.forename: Pikul
authors.initials: P
authors.lastname: Jiravanichpaisal
authors.affiliation: Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.
authors.forename: Lage
authors.initials: L
authors.lastname: Cerenius
authors.affiliation: National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Kumjeong Ku, Busan 609-735, Korea.
authors.forename: Bok Luel
authors.initials: BL
authors.lastname: Lee
authors.affiliation: Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.
authors.forename: Irene
authors.initials: I
authors.lastname: Söderhäll
authors.affiliation: Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden. Electronic address: Kenneth.Soderhall@ebc.uu.se.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Söderhäll
mesh_terms: D016980:Aeromonas hydrophila / Q000378:metabolism*; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D003400:Astacoidea; D003445:Crustacea / Q000378:metabolism* / Q000382:microbiology; D016905:Gram-Negative Bacterial Infections / Q000378:metabolism*; D008954:Models, Biological; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D010587:Phagocytosis; D011506:Proteins / Q000737:chemistry; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000737:chemistry; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D011506:Proteins; D012330:RNA, Double-Stranded; C106709:pacifastin; D014442:Monophenol Monooxygenase