Dimethylselenide and Dimethyltelluride Formation by a Strain of Penicillium

Abstract

A strain of Penicillium which produced dimethylselenide from inorganic selenium compounds was isolated from raw sewage. Sulfate and methionine enhanced growth of the fungus and its production of dimethylselenide in media containing selenite. In solutions containing selenate, methionine inhibited dimethylselenide formation while stimulating proliferation of the fungus. Dimethylselenide was also generated from inorganic selenide. Alkylation did not appear to be a significant mechanism of selenium detoxication by this organism. Dimethyltelluride was also produced by the organism from several tellurium compounds, but this product was synthesized only in the presence of both tellurium and selenium. The yields of dimethylselenide and dimethyltelluride varied with the relative concentrations of selenium and tellurium in the medium.

Bioreduction of selenite and tellurite by Phanerochaete chrysosporium

“…The particles with higher proportion of Se showed similar morphology to that of the Se nanospheres (Figures 7.5D and 4F), whereas particles with higher proportion of Te had a similar structure to that of the Te 0 needle-like particles. Fleming and Alexander (1972) reported for the first time the concurrent interaction of SeO3 2and TeO3 2with Fusarium, but there was no indication of Se-Te precipitate formation.…”

“…In the presence of both SeO3 2and TeO3 2-, a light garlic-like odor was perceived, suggesting that methylated forms of either Se or Te are being produced. Fleming and Alexander (1972) found that Penicillium was able to produce dimethyltelluride in the presence of both Se and Te, characterized by a strong-garlic-like odor. In the absence of Se, Penicillium did not generate Te volatilization, suggesting that Se was involved in the activation of the methylation process in Penicillium, allowing then the formation of Te methylated forms (Fleming and Alexander, 1972).…”

“…There has been some research on the metabolism of Se in filamentous fungi, including uptake and volatilization (Barkes and Fleming, 1974;Fleming and Alexander, 1972;Tweedie and Segel, 1970;Ramadan et al, 1988); however, the information is still scarce. The limited knowledge regarding Se-fungi interactions hampers the full exploitation of fungi in Se remediation technologies and as nSe 0 producing agents.…”

Gas chromatography

“…Umilin and coworkers (867) measured the temperature dependence of vapor pressure of bis-arenyl-7r-complexes of vanadium and successfully eluted various ethylbenzoyl-molybdedenum organometallics gas chromatographically (866). Tin (584), selenium and tellurium (262), chromium (467), and thallium (695) organometallic compounds are among those which have now been evaluated gas chromatographically, and research on the elution of nitrogen oxides (76, 334) and organophosphates, and other phosphorus esters was active (399,771).…”

Περιεκτικοτητα Σεληνιου Στα Τροφιμα Και Βιολογικα Δειγματα Και Η Σχεση Τους Με Τον Καρκινο

“…Οι πρώτες μελέτες βιοδιαθεσιμότητας των μορφών Se ήταν εκεί νες του Schwarz και των συνεργατών του [96,97] [75,99] .…”