title: Immune responses of prophenoloxidase and cytosolic manganese superoxide dismutase in the freshwater crayfish Cherax quadricarinatus against a virus and bacterium.
abstract: Prophenoloxidase (proPO) and cytosolic manganese superoxide dismutase (cytMnSOD) play crucial roles in crustacean innate immunity. In the present study, both of the above genes were cloned from hemocytes of the red claw crayfish Cherax quadricarinatus. A phylogenetic analysis of the amino acid sequences showed that C. quadricarinatus proPO and cytMnSOD were more closely related to the proPO and cytMnSOD of other crayfish than to those of penaeids, crabs, lobsters, or freshwater prawns. A tissue distribution analysis revealed that proPO was primarily expressed in hemocytes, gills, and the heart, while cytMnSOD was detected in all tissues examined. All of the crayfish artificially infected with white spot syndrome virus (WSSV) died within 4 days. According to a non-lethal dose, there was no mortality in crayfish when infected deliberately with Aeromonas hydrophila. Total hemocyte counts (THCs) had significantly decreased in crayfish at 48 and 72 h after infection with WSSV compared to the control group. In contrast, THCs of crayfish after A. hydrophila challenge had recovered by 48 and 72 h from a lower level at 24 h. There were similar responses in enzyme activities toward WSSV and A. hydrophila infection. Phenoloxidase (PO) and superoxide dismutase (SOD) activities per hemocyte significantly increased from 48 to 72 h compared to the control group. After WSSV challenge, expressions of proPO and cytMnSOD transcripts in hemocytes significantly decreased at 12h, then had respectively recovered and increased at 24 h. At 48-72 h, transcript levels were finally downregulated. No significant differences in the expression profiles of proPO and cytMnSOD were observed between the A. hydrophila-infected and control groups, besides the significant upregulation at 24h post-infection. These results implicate proPO and cytMnSOD in the immune response, and they presented similar expression patterns, although different defense mechanisms may exist for crayfish induced by WSSV and A. hydrophila.
authors.affiliation: Department of Marine Biotechnology, National Kaohsiung Marine University, Kaohsiung 81157, Taiwan, ROC.
authors.forename: Yan-Ting
authors.initials: YT
authors.lastname: Liu
authors.forename: Chin-I
authors.initials: CI
authors.lastname: Chang
authors.forename: Jinn-Rong
authors.initials: JR
authors.lastname: Hseu
authors.forename: Kuan-Fu
authors.initials: KF
authors.lastname: Liu
authors.forename: Jyh-Ming
authors.initials: JM
authors.lastname: Tsai
mesh_terms: D016980:Aeromonas hydrophila / Q000276:immunology* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D001483:Base Sequence; D004156:Catechol Oxidase / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology / Q000276:immunology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004792:Enzyme Precursors / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D005618:Fresh Water; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism; D054884:Host-Pathogen Interactions / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013482:Superoxide Dismutase / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016019:Survival Analysis; D013997:Time Factors; D046848:White spot syndrome virus 1 / Q000276:immunology* / Q000502:physiology
chemical_list: D018076:DNA, Complementary; D004792:Enzyme Precursors; C038451:pro-phenoloxidase; D004156:Catechol Oxidase; D013482:Superoxide Dismutase