Biomedical subjects

N N Amerkhanova

Publications and source records attributed to N N Amerkhanova.

3 recordsLinked to original sources

PubMed1982

[Bacterial reductive transformation of aromatic nitro compounds].

The transformation of 2,4,6-trinitrotoluene (TNT) and other aromatic nitro compounds by bacteria was studied in the course of their growth in a medium containing glucose. Various bacteria were found, for the first time, to be capable of growth in the presence of 200 mg/l of TNT and of transformation of the compound with a higher or lesser activity. The results indicate that Gram-negative bacteria play a key role in TNT transformation under natural conditions. The nitro group reduction is the principal step in the bacterial action on the studied compounds. It is noteworthy that there is no correlation between the degree of nitro reduction and the susceptibility of the bacteria to the toxic effect of benzoic acid, phenol and benzene nitro derivatives.

Alcaligenes↗

PubMedDate not supplied

[2,4,6-trinitrotoluene as a nutritional source for bacteria].

2,4,6-Trinitrotoluene (TNT) is one of the most stable toxic substances belonging to nitroaryls which is introduced into water reservoirs with industrial wastes. Its metabolism by microorganisms was studied in this work. The nitrogen of TNT is less accessible for Pseudomonas denitrificans than for Escherichia coli. In the latter case, TNT can be compared with ammonium sulphate. As a source of carbon, TNT is not utilized at all by E. coli and is hardly accessible for Ps. denitrificans. The data obtained in this work are valuable for intensifying the decomposition of TNT in natural and waste waters. This process can be stimulated in the conditions of biological purification of waters by combining waste waters containing TNT with other industrial waters containing accessible organic substances.

Carbon↗

PubMedDate not supplied

[Characteristics of nitroreduction as the key stage in the microbial destruction of aromatic nitro compounds].

The reduction of nitrogroups of 2,4,6-trinitrotoluene (TNT) and other nitroaromatic compounds under the influence of Pseudomonas denitrificans and Escherichia coli enzymes was investigated. Quantitative measurements of the immediate stable products of TNT reduction showed that its reducing attack increased with bacterial age. However, preferential reduction of the nitrogroup in position 2 was typical of bacterial cells of any age, being maintained at pH 5.5 to 7.8. The bacterial reduction in vitro was NAD(P)H- (or NAD(P)H-generating systems) dependent. The nitroreduction was stimulated by only FAD and Mn2+ and Mg2+ out of flavins and metal ions tested. The lack of substrate specificity in the nitroreductases under study is indicated by the reducing capacity (in descending order) of nitroderivatives of benzene, toluene, benzoate, and phenol.

Escherichia coli↗