Uptake,transformation and fixation of Se(VI) by a mixed selenium-tolerant ecosystem

The uptake, transformation and fate of Se, added as selenate to a mixed microbial ecosystem containing Se-tolerant bacteria and cyanobacteria, has been studied in simulated laboratory ponds. There was evidence of concerted activities of the microbial community in the system. Motile bacteria were responsible for transport into a surface mat and the combined actions of the microbial consortium provide chemical conditions under which the Se could be reduced to the elemental form and physically entrained in the mat. Strong qualitative indications of the formation of volatile alkylselenium compounds were also observed. The removal of Se from the water column was rapid and essentially quantitative. The advantages of such biological ecosystems for remediation of Se-contaminated aquatic ecosystems are discussed.     

In situ and in vitro antioxidant activity of sweetpotato anthocyanins

Anthocyanins from a variety of fruits and vegetables have been shown to possess potent antioxidant activity in vitro, but scavenging of free radicals by anthocyanins has only been demonstrated in situ in the leaves of certain plants. We report on a new sweetpotato that exhibits mottled purple flesh attributable to high concentrations of anthocyanins. By perfusing transverse sweetpotato sections with the reactive oxygen species H(2)O(2), followed by the H(2)O(2) sensitive fluorochrome scopletin, we show that anthocyanins act as antioxidants in situ within the sweetpotato storage roots. We also demonstrate in vitro antioxidant activity by sweetpotato anthocyanins, where an additive effect with hydroxycinnamic acids is observed. Anthocyanic foods have been shown to offer protection against a variety of degenerative disease processes. Given that sweetpotato can be eaten several hundred grams at a time and as a staple, these data are consistent with the possibility of superior health protection by anthocyanic varieties of sweetpotato in comparison to most common fruits and vegetables.