Phenoloxidase is an important component of the defense against Aeromonas hydrophila Infection in a crustacean, Pacifastacus leniusculus.
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.
Liu
Haipeng
H
Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.
Jiravanichpaisal
Pikul
P
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.
Cerenius
Lage
L
Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.
Lee
Bok Luel
BL
National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Kumjeong Ku, Busan 609-735, Korea.
Söderhäll
Irene
I
Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden.
Söderhäll
Kenneth
K
Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden. Electronic address: Kenneth.Soderhall@ebc.uu.se.
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
D000890:Anti-Infective Agents; D011506:Proteins; D012330:RNA, Double-Stranded; C106709:pacifastin; D014442:Monophenol Monooxygenase