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Biomedical subjects

M Alexander

Publications and source records attributed to M Alexander.

At least 361 records · Page 20Linked to original sources
PubMed1974

Evolution of dimethylselenide from soils.

Alcohols, carbonyl compounds, and fatty acids were formed in two glucose-amended soils incubated under argon, but dimethylselenide was evolved under argon only from one, a selenium-rich clay, after the addition of selenite and glucose. Substantial quantities of dimethylselenide were released from the four soils tested when they were incubated with glucose and selenite in air. No dimethylselenide was produced in the selenium-rich clay soil in air if it received glucose but no selenite.

Air↗
PubMed1973

Effect of phosphate and other anions on trimethylarsine formation by Candida humicola.

Phosphate inhibited the formation of trimethylarsine from arsenite, arsenate, and monomethylarsonate, but not from dimethylarsinate, by growing cultures of Candida humicola. Phosphite suppressed trimethylarsine production by growing cultures from monomethylarsonate but not from arsenate and dimethylarsinate, and hypophosphite caused a temporary inhibition of both proliferation and the conversion of these three arsenic sources to trimethylarsine. Resting cells of C. humicola derived from cultures grown in arsenic-free media generated the volatile arsenical only after a lag phase. High antimonate concentrations reduced the rate of conversion of arsenate to trimethylarsine by resting cells, but nitrate was without effect.

Antimony↗
PubMed1973

Microbial formation of nitrosamines in vitro.

Mortierella parvispora and an unidentified bacterium converted trimethylamine to dimethylamine, and the bacterium (but not the fungus) formed dimethylnitrosamine in the presence of nitrite. Dimethylnitrosamine also appeared in cell suspensions of Escherichia coli and Streptococcus epidermidis and in hyphal mats of Aspergillus oryzae incubated with dimethylamine and nitrate. Suspensions of a number of microorganisms produced N-nitrosodiphenylamine from diphenylamine and nitrite at pH 7.5, and soluble enzymes catalyzing the N-nitrosation of diphenylamine were obtained from two of these organisms. In the presence of these enzymes, several dialkylamines were converted to the corresponding N-nitroso compounds.

Aspergillus↗