title: Early transcriptional response to the parasitic dinoflagellate Hematodinium in hepatopancreas of Portunus trituberculatus.
abstract: The swimming crab Portunus trituberculatus supports a large proportion of crab aquaculture in China. In the last decade, the sustainable culture of this crab was threatened by the parasitic dinoflagellate Hematodinuim, resulting in massive mortality (up to 95%) in severely impacted culture ponds. Previous studies of Hematodinium were mainly focused on histology, molecular characterization, epizootiology, etc., with limited studies conducted to explore this specific host-parasite interaction. Thus, to give a primary insight into the anti-parasitic immune response at the critical stage of infection, the expression levels of 8 immune-related genes together with enzyme activities of phenoloxidase (PO), alkaline phosphatase (AKP), and acid phosphatase (ACP), were evaluated in hepatopancreas during 3-192h (h) post inoculation. Hematoxylin-eosin (H&E) staining showed noticeable pathological changes in hepatopancreas. The enzyme activities of PO, AKP, and ACP were significantly induced after inoculation. The changes of the prophenoloxidase (proPO) transcripts and the constantly enhanced PO activity reflected the critical function of the proPO system in resisting against the parasites. The decreased expression levels of LGBP and PPAF implied an immunosuppressive mechanism of the parasites against the host proPO system. And the significant variations in transcriptional levels of two important proteinase inhibitors (serpin, α2m) and three P. trituberculatus clip-domain serine proteinases (PTcSPs) suggested that the parasites could affect proteinase cascade reactions associated with immune response by destroying the balance between serine proteinases and the inhibitors. Moreover, the results indicated that the hepatopancreas of P. trituberculatus was significantly affected by invasion of the parasite, and hepatopancreas played important roles in the crustacean innate immunity against the parasitic infection.
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Shuqun
authors.initials: S
authors.lastname: Song
authors.affiliation: Key Lab of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: cwli@qdio.ac.cn.
authors.forename: Caiwen
authors.initials: C
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003386:Brachyura / Q000469:parasitology*; D004141:Dinoflagellida / Q000276:immunology*; D020869:Gene Expression Profiling; D017125:Genes, Protozoan; D043143:Hepatopancreas / Q000276:immunology / Q000469:parasitology*; D006790:Host-Parasite Interactions / Q000502:physiology*; D016133:Polymerase Chain Reaction
keywords: Crustacean; Enzyme activity; Histopathology; Innate immunity; Parasite; Transcription