Nitric oxide cellular actions

H. Ohshima, Y. Yoshie, S. Auriol and I. Gilibert, Antioxidant and pro-oxidant actions of flavonoids effects on DNA damage induced by nitric oxide, per-oxynitrite and nitroxyl anion, Free Radic. Biol. Med., 25 (1998) 1057-1065. M.K. Johnson and G. Loo, Effects of egpigallocatechin gallate and quercetin on oxidative damage to cellular DNA, Mutat. Res., 459 (2000) 211-218. 

Other possible modes of action may centre on stimulation of T cells (this occurred with the live aroA mutant of A. salmonicida Marsden et al., 1996), which introduces the role of cellular and innate rather than humoral immunity as the mode of action. For this, examples include A. hydrophila LPS (Baba et al., 1988) and E. tarda ECPs (Lee et al., 2010). Of course, there could be involvement of humoral, cell-mediated and innate immune parameters as stated for the i.p. administration of a live auxotrophic aroA mutant of A. hydrophila with effectiveness against furunculosis in rainbow trout (Vivas et al, 2004). Other possibilities include the evidence that one commercial formalized whole cell V. anguillarum vaccine induces Mx gene (these are inducible by Type I interferons and have a role in antiviral activity) expression in Atlantic salmon after administration intraperitoneally (Acosta et al., 2004). In another example, vaccination with P. damselae subsp. piscicida cells were found to enhance the nitric oxide response, i.e. the production of reactive nitrogen intermediates with their antimicrobial activities, to infection with the pathogen, and is correlated with the level of protection (Acosta et al., 2005). There was inhibition of F columnare adhesion to the skin of immersion vaccinated eel (Mano et al., 1996). Finally, mention will be made of a possible mechanism of protection of V. anguillarum vaccines that may well involve the inhibition of bacterial attachment by unknown factors in the skin mucus (Kawai and Kusuda, 1995). 

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