RESUMEN
To design a reasonable and effective remediation scheme for soil in contaminated sites, it is necessary to understand the microbial communities in the soil. Samples were collected at different depths (0 cm to 400 cm) in four locations: one that was persistently contaminated and near an oil well, one that was historically contaminated in the middle of the site, one in a mud pit, and one in farmland. High-throughput sequencing of the V4 region of 16S rRNA in these samples was performed. In addition to physico-chemical properties of the soil, the α-diversity, species composition, and differences in species between groups of microorganisms were analyzed, and a principal coordinate analysis and canonical correlation analysis were conducted. Results showed that oil and salt contents in soils were the dominant factors affecting microbial community structure. Hydrocarbon-degrading microorganisms were abundant in oil-contaminated soils, whereas halophilic hydrocarbon-degrading microorganisms were present in soils with high salt contents. Therefore, hydrocarbon-degrading microorganisms might be useful in remediation of oil-contaminated sites.
Asunto(s)
Bacterias/clasificación , Contaminación por Petróleo , Microbiología del Suelo , Contaminantes del Suelo , Biodegradación Ambiental , ARN Ribosómico 16S/genética , SueloRESUMEN
Whole-cell patch-clamp technique was used to investigate the effect of ginsenoside Rb(3) (Rb(3)), an active constituent of Panax ginseng, on glycine receptor activity in immature hippocampal neurons, which were dissociated acutely from hippocampal CA(1) area in Sprague-Dawley rats aging 10-14 days using the method of enzyme digestion with mechanical dissociation. As a result, glycine elicited an inward current (I(gly)) in a concentration-dependent manner in approximately 86% of those isolated neurons tested. This current was strychnine-sensitive. Rb(3) itself did not elicit any membrane currents. However, coapplication of Rb(3) inhibited peak current of I(gly). This depressant effect of Rb(3) varied with its concentrations. At a concentration of 0.1 micromol/L, ginsenoside Rb(3) had the most significant inhibition, with a net reduction of 31% in average. Moreover, the inhibition of I(gly) by Rb(3) did not depend on the membrane potential. Rb(3) (0.1 micromol/L) presented inhibitory effect on I(gly) mainly at higher glycine concentrations (>100 micromol/L), and decreased maximal glycine efficacy. This effect was the same as that of a non-competitive antagonist of glycine receptors. Finally, we found that Rb(3) prolonged the time constant of activation of I(gly). It is therefore suggested that ginsenoside Rb(3), possibly as a non-competitive antagonist, could inhibit strychnine-sensitive glycine current at a dose-dependent manner in acutely dissociated hippocampal CA(1) neurons of young rats, and decrease of affinity of glycine to receptors and delay of receptor activation may be involved in this inhibition. Inhibitory effect of ginsenoside Rb(3) on I(gly) is possibly one of the bases of many pharmacological actions of Panax ginseng.