Demonstration of nitric oxide synthase activity in crustacean hemocytes and anti-microbial activity of hemocyte-derived nitric oxide

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 2006-05, Vol.144 (1), p.11-17
• Main Authors: Yeh, Feng-Ching, Wu, Su-Hua, Lai, Chi-Yung, Lee, Chi-Ying
• Format: Article
• Language: English
• Subjects: Animals; Anti-Infective Agents - pharmacology; Astacoidea - enzymology; Bactericidal activity; Calcium - metabolism; Cambaridae; Cell Adhesion - drug effects; Colony-Forming Units Assay; Crustacean; Enzyme Inhibitors - pharmacology; Hemocyte; Hemocytes - enzymology; Lipopolysaccharide; Lipopolysaccharides - pharmacology; Nitric oxide; Nitric Oxide - pharmacology; Nitric Oxide Donors - pharmacology; Nitric oxide synthase; Nitric Oxide Synthase - antagonists & inhibitors; Nitric Oxide Synthase - metabolism; Nitroprusside - pharmacology; omega-N-Methylarginine - pharmacology; Procambarus clarkii; Staphylococcus aureus; Staphylococcus aureus - drug effects; Staphylococcus aureus - growth & development
• ISSN: 1096-4959; 1879-1107
• DOI: 10.1016/j.cbpb.2006.01.007

We determined the biochemical characteristics of nitric oxide synthase (NOS) in hemocytes of the crayfish Procambarus clarkii and investigated the roles of hemocyte-derived NO in host defense. Biochemical analysis indicated the presence of a Ca 2+-independent NOS activity, which was elevated by lipopolysaccharide (LPS) treatment. When bacteria ( Staphylococcus aureus) and hemocytes were co-incubated, adhesion of bacteria to hemocytes was observed. NO donor sodium nitroprusside (SNP) significantly increased the numbers of hemocytes to which bacteria adhered. Similarly, LPS elicited bacterial adhesion and the LPS-induced adhesion was prevented by NOS inhibitor N G-monomethyl- l-arginine ( l-NMMA). Finally, plate count assay demonstrated that addition of LPS to the hemocytes/bacteria co-incubation resulted in a significant decrease in bacterial colony forming unit (CFU), and that l-NMMA reversed the decreasing effect of LPS on CFU. The combined results demonstrate the presence of a Ca 2+-independent LPS-inducible NOS activity in crayfish hemocytes and suggest that hemocyte-derived NO is involved in promoting bacterial adhesion to hemocytes and enhancing bactericidal activity of hemocytes.