Biodegradation of 4-nitrophenol by indigenous microbial populations in Everglades soils

The Everglades in South Florida are a unique ecological system. As a result of the widespread use of pesticides and herbicides in agricultural areas upstream from these wetlands, there is a serious potential for pollution problems in the Everglades. The purpose of this study was to evaluate the ability of indigenous microbial populations to degrade xenobiotic organic compounds introduced by agricultural and other activities. Such biodegradation may facilitate the remediation of contaminated soils and water in the Everglades. The model compound selected in this study is 4-nitrophenol, a chemical commonly used in the manufacture of pesticides. The mineralization of 4-nitrophenol at various concentrations was studied in soils collected from the Everglades. At concentrations of 10 and 100 microg/g soil, considerable mineralization occurred within a week. At a higher concentration, i.e., 10 mg/g soil, however, no mineralization of 4-nitrophenol occurred over a 4-month period; such a high concentration apparently produced an inhibitory effect. The rate and extent of 4-nitrophenol mineralization was enhanced on inoculation with previously isolated nitrophenol-degrading microorganisms. The maximum mineralization extent measured, however, was less than 30% suggesting conversion to biomass and/or unidentified intermediate products. These results indicate the potential for natural mechanisms to mitigate the adverse effects of xenobiotic pollutants in a complex system such as the Everglades.     

Structure of the thymus gland of the rat in the prenatal and early postnatal periods of development after exposure to tetracycline during the period of fetogenesis

Structure of the thymus in Wistar rats has been studied during antenatal and early postnatal periods of ontogenesis by means of histological, morphometric and electron microscopic methods. Theraputic doses of tetracycline hydrochloride have been administered during fetogenesis (15-20 days of pregnancy). An accelerated formation of the thymic structures, cellular blasttransformation in the thymic cortex and movement of lymphocytes from the cortex into medulla and increased secretory activity of epithelioreticulocytes have been revealed. The data obtained are considered as a display of the organ's immune response to tetracycline administration.     

Use of DNA polymorphism detected by M13 phage DNA in population studies]

Hypervariable "minisatellite" regions detected in human genome by wild-type phage M13 DNA were found to have high polymorphism and somatic stability. Analysis of individual specific patterns of hybridization of 44 human DNAs from the Kirov province is presented. Molecular weight of fragments varied from 2 to 6 kb. Mean frequency of a fragment in the population under study is p = 0.294 +/- 0.158. The mean number of fragments per individual is 11.6 +/- 1.8. Comparison between the Kirov population and that of Krasnodar studied earlier was carried out. The mean genetic distance between Kirov and Krasnodar populations calculated according to Nei is 0.2082. The possibility of using in population-genetic studies of hypervariable DNA markers having fingerprint type of hybridization is discussed.     

Evaluation of the sanative action of rifampicin on the meningococcal carrier state]

The results of the epidemiological control experiment on the efficacy of rifampicin in sanation of meningococci carriers are presented. The preliminary study of rifampicin sensitivity of 41 freshly isolated nasopharyngeal meningococcal strains showed that the MIC of the drug for 63 per cent of the isolates was 0.04--0.1 gamma/ml. Sanation was performed for 2 days; 1.2 g of the drug was used during the treatment course. The results of examination of 91 meningococci carriers showed that 4 days after the sanation the specific weight of the persons isolating no meningococci was reliably higher in the experimental group than that in the control group. The coefficient of rifampicin efficiency was 70.8 per cent. 10 days after sanation the difference in the level of the carriers isolating no meningococci in the experimental and the control groups was statistically insignificant. Therefore, the carriers treated with the drug received temporary protection from the causative agent at an average for 1 week. Later on they could become carriers again. As a result of sanation no changes in the meningococcal sensitivity to rifampicin was observed.     

Changes in the functional activity of macrophages, their morphology and metabolism under the influence of several biologically active substances]

The functional activites of peritoneal macrophages, their morphology and metabolism under the effects of some metabolic inhibitors and various biological ngents were studied. A correlation between functions of macrophages (speading on glass, pinoctosis of virus particles), changes in their metabolism (RNA and protein synthesis; specific activity ofcreatinkinase and catepsin), properties of the macrophages plasma membrane, and the number of lysosomes, was found.     

Template Properties of 5-Methyl-2'-Deoxycytidine and 5-Hydroxymethyl-2'-Deoxycytidine in Reactions with Human Translesion and Reparative DNA Polymerases

Molecular Biology - 5-Methyl-2'-deoxycytidine (mC) and the product of its controlled oxidation, 5-hydroxymethyl-2'-cytidine (hmC), play a key role in the epigenetic regulation of gene...