title: Production of reactive oxygen species by hemocytes from the cattle tick Boophilus microplus.
abstract: We have investigated the phagocytic activity and the production of reactive oxygen species (ROS) by hemocytes from the cattle tick Boophilus microplus. Two main types of hemocytes were detected in tick hemolymph: plasmatocytes and granulocytes. The plasmocytes were the most abundant cells, being responsible for the in vivo phagocytosis of yeast. ROS production was evaluated by luminol-amplified luminescence and phenol red oxidation. The luminescence increased when hemocytes were incubated with bacteria, zymosan, or phorbol 12-miristate 13-acetate (PMA). The luminescence was inhibited by superoxide dismutase and catalase, which are antioxidant enzymes that remove superoxide and hydrogen peroxide, respectively. The phenol red oxidation assay also showed an increase in the level of hydrogen peroxide produced by hemocytes stimulated with bacteria and PMA. Taken all together, our data indicate that tick hemocytes are able to produce ROS during the phagocytic process similarly to vertebrate phagocytes.
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil.
authors.forename: L S
authors.initials: LS
authors.lastname: Pereira
authors.forename: P L
authors.initials: PL
authors.lastname: Oliveira
authors.forename: C
authors.initials: C
authors.lastname: Barja-Fidalgo
authors.forename: S
authors.initials: S
authors.lastname: Daffre
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D002417:Cattle; D005260:Female; D006434:Hemocytes / Q000145:classification / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D026863:Ixodidae / Q000378:metabolism*; D010587:Phagocytosis; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
chemical_list: D017382:Reactive Oxygen Species; D015054:Zymosan; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D013755:Tetradecanoylphorbol Acetate