title: Superoxide dismutase expression and H2O2 production by hemocytes of the trematode intermediate host Lymnaea stagnalis (Gastropoda).
abstract: Snail hemocytes mobilise ROS-generating enzymes during oxidative burst similar to those of mammalian leukocytes. We report herein the identification of an inducible Cu/Zn superoxide dismutase, which converts O2- to H2O2, in hemocytes of the pond snail Lymnaea stagnalis. The deduced amino acid sequence with all characteristic residues (His44,46,61,69,78 and 118, Asp81, Cys55/144, Arg141 and the Greek Key loop region Glu119-Leu/Val142) includes an open reading frame of 155 AA. Changes in Cu/ZnSOD gene expression induced by stimulation with Zymosan or trematode larvae were examined in a time course. Activated hemocytes significantly up-regulate Cu/ZnSOD expression during 2-48 h upon stimulation with the maximal induction at 45 min during phagocytosis and at 12 h during encapsulations. This increase in Cu/ZnSOD expression paralleled the increasing production of hydrogen peroxide by hemocytes. Thus, intracellular or extracellular targets elicit an induced expression of Cu/ZnSOD and the generation of elevated amounts of hydrogen peroxide by L. stagnalis hemocytes, reflecting a significant activation of their host defense function.
authors.affiliation: Institute for Tropical Medicine, Tuebingen D-72074, Germany. ulrike.zelck@uni-tuebingen.de
authors.forename: U E
authors.initials: UE
authors.lastname: Zelck
authors.forename: B
authors.initials: B
authors.lastname: Janje
authors.forename: O
authors.initials: O
authors.lastname: Schneider
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D006434:Hemocytes / Q000201:enzymology* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D015151:Immunoblotting; D008195:Lymnaea / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000469:parasitology; D008969:Molecular Sequence Data; D010587:Phagocytosis / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012550:Schistosoma mansoni; D012555:Schistosomiasis mansoni / Q000201:enzymology / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D015054:Zymosan / Q000378:metabolism
chemical_list: D015054:Zymosan; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase