Oxidative phosphorylation biocides

Mechanistic studies have shown that TBT and certain other forms of trialkyltin have two distinct modes of toxic action in vertebrates. On the one hand they act as inhibitors of oxidative phosphorylation in mitochondria (Aldridge and Street 1964). Inhibition is associated with repression of ATP synthesis, disturbance of ion transport across the mitochondrial membrane, and swelling of the membrane. Oxidative phosphorylation is a vital process in animals and plants, and so trialkyltin compounds act as wide-ranging biocides. Another mode of action involves the inhibition of forms of cytochrome P450, which was referred to earlier in connection with metabolism. This has been demonstrated in mammals, aquatic invertebrates and fish (Morcillo et al. 2004, Oberdorster 2002). TBTO has been shown to inhibit P450 activity in cells from various tissues of mammals, including liver, kidney, and small intestine mucosa, both in vivo and in vitro (Rosenberg and Drummond 1983, Environmental Health Criteria 116). 

Triphenyl- and tributyltin compounds have strongly biocidal properties and are employed in some agricultural fungicides and wood preservatives42. Other possible applications include disinfectants for use in hospitals and for the eradication of snails that transmit bilharzia. However, these compounds are potentially hazardous because of the ease with which they inhibit oxidative phosphorylation in man. Oral administration of diethyltin diiodide as a treatment for boils led to many deaths43. ... 

The results on Table 2 shows a Methylene Bisthiocyanate based biocide. The mechanism of action of this biocide is to block the transfer of electrons from primary cytochrome dehydrogenase, and thereby cause an uncoupling of oxidative phosphorylation . Here the Total ATP results initially increase on treatment with the biocide a small increase in Free ATP is also evident along with a reduction in viable counts. With time there is a reduction in Total and Free ATP along with a further reduction in the plate count results. 

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