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Biomedical subjects

E J DaSilva

Publications and source records attributed to E J DaSilva.

5 recordsLinked to original sources
PubMed1978

Effects of some inorganic elements on nitrogen-fixation in blue-green algae and some ecological aspects of pollution.

Nitrogen-fixation by two species of Nostoc, one of them a lichen phycobiont, was generally stimulated by low concentrations of arsenic, cadmium, nickel, lead, palladium, and zinc. Higher concentrations (0.025 to 0.125 ppm) of arsenic, nickel, and palladium were also stimulatory; however, higher concentrations of cadmium, lead, and zinc tended to inhibit fixation. With the exception of palladium and zinc at low concentrations these six tested elements tended to inhibit nitrogen-fixation in Chlorogloea fritschii and Westiellopsis sp.

Arsenic↗
PubMed1975

Effect of pesticides on blue-green algae and nitrogen-fixation.

The effects of the pesticides, amitrol, a derivative of amitrol (viz. 3,5-diamino-1,2,4-triazole), diquat, paraquat, linuron, MCPA, malathion, and monuron, were studied on the nitrogen-fixing algae, Anabaena cylindrica, Aulosira sp., Calothrix elenkenii. Chlorogloeae frischii, Cylindrospermum muscicola, Nostoc sp. from Collema tenax, Nostoc muscorum Tolypothrix tenuis, and Westiellopsis sp. In general, two types of response were discernible; an initial period of depression succeeded by an increased activity and an initial period of depression followed by a distinct decrease on prolonged incubation. The results indicate that some pesticidal compounds can severely limit the nitrogen-fixing capacities of blue-green algae, thereby affecting the overall nitrogen economy of soils in general.

Culture Media↗