Losses of diesel oil by volatilisation and effects of diesel oil on seed germination and seedling growth.

For phytoremediation to be effective, seeds must germinate and subsequently grow, or seedlings must become established, in contaminated soil. In this study, the effect of diesel oil on the viability of seeds of white clover and ryegrass together with long term abiotic diesel oil loss were investigated. Losses of diesel by volatilisation were found to be as high as 58% over 360 days suggesting that volatilisation (abiotic loss) may be a significant method of contaminant removal that may have been previously underestimated or overlooked in short term studies. White clover and ryegrass seeds were able to germinate in the presence of volatile diesel components and following 24 weeks immersion in diesel oil, which suggested that properties of their seed coats prevented diesel oil causing damage to the seeds.

Ferritin-dependent lipid peroxidation by stimulated neutrophils: inhibition by myeloperoxidase-derived hypochlorous acid but not by endogenous lactoferrin.

Human neutrophils stimulated with phorbol myristate acetate or formylmethionylleucylphenylalanine caused superoxide-dependent release of iron from feritin, measured as the formation of a ferrous-ferrozine complex. The stimulated cells also caused ferritin-dependent peroxidation of phospholipid liposomes. Peroxidation was inhibited by lactoferrin, but only at concentrations considerably in excess of what could be achieved by release of endogenous lactoferrin. Peroxidation was enhanced by catalase and methionine, especially when stimulants that release myeloperoxidase were used. Peroxidation was inhibited by added myeloperoxidase. These results are explained by myeloperoxidase catalysing the formation of hypochlorous acid (HOCl) and the HOCl reacting with the lipid to inhibit peroxidation. Thus, neutrophils are able to use ferritin to promote lipid peroxidation. This may be limited under some conditions by iron binding to lactoferrin or transferrin, and more generally by reactions of the lipid with myeloperoxidase-derived HOCl. However, the latter reactions themselves may be harmful.