Quinone mediated electron transport system in the filarial parasite Setaria digitata.

Setaria digitata, a cattle filarial parasite, is known to have peculiarities such as hydrogen peroxide (H2O2) production, cyanide insensitivity, absence of cytochromes and presence of quinones. Estimation of mitochondrial H2O2 with different substrates and inhibitors showed that salicylhydroxamic acid (SHAM), the alternative oxidase inhibitor, inhibited the H2O2 production maximally. Based on the inhibitory studies with rotenone, antimycin A, o-hydroxydiphenyl, SHAM and 2 thenoyltrifluoroacetone, a mechanism for the electron transport is proposed. Quinone Q8 seems to have a central role, hence inhibitors at the level of quinones might prove to be effective in designing drugs for filariasis.