Environmental transport of endogenous dairy manure estrogens

Although estrogens originating from dairy manure applied to agricultural soils as a fertilizer can potentially contaminate surface water and groundwater, the variables that control transport are poorly understood. Our objective was to assess the potential for off-site movement of endogenous dairy cattle estrogens when manure is applied on fields at agronomically relevant fertilization rates. Estrone (E1), 17α-estradiol (α-E2), and 17β-estradiol (β-E2) were used in laboratory sorption, desorption, and transformation incubations with both manure and an agriculturally relevant soil. Sorption on manure containing 44% organic carbon exceeded sorption on soil containing 0.8% organic carbon by 20 to 150 times, following the pattern of β-E2 > α-E2 > E1. Approximately 20% of E1 and 17% of α-E2 were desorbed from manure, whereas only about 4% of β-E2 was desorbed. Thirty to seventy percent of α-E2 and β-E2 were converted to E1 in soil and manure, making it imperative that transformation reactions be considered when predicting transport and potential biological effects in the environment. Overall results indicate that high organic carbon concentrations and relatively low amounts of desorption inhibit the potential for off-site transport of endogenous dairy manure estrogens.     

Effect of alkyl hydroxybenzenes on the properties of dioxygenases

The aim of the present work was to investigate the influence of alkylhydroxybenzenes (AHBs) and tyrosol, which belong to cell differentiation factors d(1) group of autoregulators on properties of biodegradation enzymes, catechol 1,2-dioxygenase (Cat 1,2-DO) and methylcatechol 1,2-dioxygenase (MCat 1,2-DO) of Rhodococcus opacus 6a. AHBs were found to have a greater effect on MCat 1,2-DO than on Cat 1,2-DO. It was expressed by more pronounced changes in the activity of MCat 1,2-DO with unsubstituted catechol at different AHB concentrations and by increasing thermostability of MCat 1,2-DO compared to Cat 1,2-DO under the protective action of AHBs. The compound C(7)-AHB shifted the maximum of dioxygenase activities towards higher temperatures and increased their operation optimum. AHBs changed the specificity constant of dioxygenases by decreasing/increasing the K(m)/V(max) value. For example, the increase in the V(max) value of 3,6-dichlorocatechol oxidation by Cat 1,2-DO in the presence of C(7)-AHB was 300-fold higher compared to the same reaction without AHB. The influence of cell differentiation factors on the properties of dimeric enzymes has been shown for the first time. It gives an idea of how the specificity of enzymes can be changed in vivo when strains contact new substrates. The work has shown the possibility of modification of the properties of dimeric enzymes towards the extension of enzyme activity with difficulty converted substrates or in more extreme conditions, which may be important for biotechnological processes.     

Benzoate degradation by Rhodococcus opacus 1CP after dormancy: Characterization of dioxygenases involved in the process

The process of benzoate degradation by strain Rhodococcus opacus 1CP after a five-year dormancy was investigated and its peculiarities were revealed. The strain was shown to be capable of growth on benzoate at a concentration of up to 10 g L^?1. The substrate specificity of benzoate dioxygenase (BDO) during the culture growth on a medium with a low (200–250 mg L^?1) and high (4 g L^?1) concentration of benzoate was assessed. BDO of R. opacus 1CP was shown to be an extremely narrow specificity enzyme. Out of 31 substituted benzoates, only with one, 3-chlorobenzoate, its activity was higher than 9% of that of benzoate. Two dioxygenases, catechol 1,2-dioxygenase (Cat 1,2-DO) and protocatechuate 3,4-dioxygenase (PCA 3,4-DO), were identified in a cell-free extract, purified and characterized. The substrate specificity of Cat 1,2-DO isolated from cells of strain 1CP after the dormancy was found to differ significantly from that of Cat 1,2-DO isolated earlier from cells of this strain grown on benzoate. By its substrate specificity, the described Cat 1,2-DO was close to the Cat 1,2-DO from strain 1CP grown on 4-methylbenzoate. Neither activity nor inhibition by protocatechuate was observed during the reaction of Cat 1,2-DO with catechol, and catechol had no inhibitory effect on the reaction of PCA 3,4-DO with protocatechuate.     

Variability of enzyme system of Nocardioform bacteria as a basis of their metabolic activity

The present review describes some aspects of organization of biodegradative pathways of Nocardioform microorganisms, first of all, with respect to their ability to degrade aromatic compounds, mostly methylbenzoate, chlorosubstituted phenols, and chlorinated biphenyls and the intermediates of their transformation: 4-chlorobenzoate and para-hydroxybenzoate. Various enzyme systems induced during degradation processes are defined. The ability of microorganisms to induce a few key enzymes under the influence of xenobiotics is described. This ability may increase the biodegradative potential of strains allowing them to survive in the changing environment or demonstrate to some extent the unspecific response of microorganisms to the effect of toxicants. Nocardioform microorganisms responsible for degradation of such persistent compounds as polychlorinated biphenyls, polyaromatic hydrocarbons, chlorinated benzoates and phenols and other xenobiotics are characterized. The possibility of using Nocardioform microorganisms in some aspects of biotechnology due to their ability to produce some compounds important for industry is also estimated.     

Optimization of fuel briquette production from cassava peels,plantain peels and corn cobs

Journal of Material Cycles and Waste Management - Mechanical properties enable to handle storage and transport of fuel briquette. Binder is key element of these mechanical properties. Biobinder is...     

Soil organic matter and biological activity under long-term contamination with copper

Environmental Geochemistry and Health - Organic matter (OM) and enzymes activity can act as indicators of the time and level of soil contamination with heavy metal. The goal of this study is...     

Sustainability of agricultural and wild cereals to aerotechnogenic exposure

In recent decades, the problem of the constantly increasin level of anthropogenic load on the environment is becoming more and more acute. Some of the most dangerous pollutants entering the environment from industrial emissions are heavy metals. These pollutants are not susceptible to biodegradation over time, which leads to their accumulation in the environment in dangerous concentrations. The purpose of this work is to study the sustainability of cultivated and wild plants of the Poaceae family to aerotechnogenic pollution in the soil. The content of heavy metals in couch grass (Elytrigia repens (L.) Nevski), meadow bluegrass (Poa pratensis L.) and soft wheat (Triticum aestivum) plants grown in the impact zone of Novocherkassk Power Station has been analyzed. Contamination of cultivated and wild cereals with Pb, Zn, Ni and Cd has been established. It has been shown that the accumulation of heavy metals is individual for each plant species. An average and close correlation have been established between the total HM content and the content of their mobile forms in the soil and their content in plants. For the plants studied, the translocation factor (TF) and the distribution coefficient (DC) of HM have been calculated. The TF is formed by the ratio of the concentration of an element in the root plant dry weight to the content of its mobile compounds in the soil. The DC value makes it possible to estimate the capacity of the aboveground parts of plants to absorb and accumulate elements under soil pollution conditions and is determined as the ratio of the metal content in the aboveground biomass to its concentration in the roots. TF and DC values have shown a significant accumulation of elements by plants from the soil, as well as their translocation from the root system to the aboveground part. It has been revealed that even within the same Poaceae family, cultural species are more sensitive to man-made pollution than wild-growing ones.

     

Improved xenobiotic-degrading activity of Rhodococcus opacus strain 1cp after dormancy

The goals of the present work were as follows: to obtain the dormant forms of R. opacus 1cp; to study the phenotypic variability during their germination; to compare phenotypic variants during the growth on selective and elective media; and to reveal changes in the ability of the strain to destruct xenobiotics that had not been degradable before dormancy. It was shown that Rhodococcus opacus 1cp (the strain degrading chlorinated phenols) became able to utilize a broader spectrum of xenobiotics after storage in the dormant state. Germination of the dormant forms of R. opacus 1cp on an agarized medium was followed by emergence and development of phenotypic variants that could grow on 4-chlorophenol and 2,4,6-trichlorophenol without adaptation. The cells of R. opacus 1cp phenotypic variants also utilized all of the tested chlorinated phenols: 2,3-, 2,5-, and 2,6-dichloro-, 2,3,4- and 2,4,5-trichloro-, pentachlorophenol, and 1,2,4,5-tetrachlorobenzene in concentrations up to 60 mg/L, though at the lower rates than 4-CP and 2,4,6-TCP. The improved degradation of chlorinated phenols by R. opacus strain 1cp exposed to the growth arrest conditions demonstrates the significance of dormancy for further manifestation of the adaptive potential of populations. A new principle of selection of variants with improved biodegradative properties was proposed. It embraces introduction of the dormancy stage into the cell life cycle with subsequent direct inoculation of morphologically different colonies into the media with different toxicants, including those previously not degraded by the strain.     

Interactive effects of cadmium and hypoxia on metabolic responses and bacterial loads of eastern oysters Crassostrea virginica Gmelin

Pollution by toxic metals including cadmium (Cd) and hypoxia are important stressors in estuaries and coastal waters which may interactively affect sessile benthic organisms, such as oysters. We studied metabolic responses to prolonged hypoxic acclimation (2 weeks at 5% O₂) in control and Cd-exposed (30 d at 50 μg L⁻¹ Cd) oysters Crassostrea virginica, and analyzed the effects of these stressors on abundance of Vibrio spp. in oysters. Hypoxia-acclimated oysters retained normal standard metabolic rates (SMR) at 5% O₂, in contrast to a decline of SMR observed during acute hypoxia. However, oysters spent more time actively ventilating in hypoxia than normoxia resulting in enhanced Cd uptake and 2.7-fold higher tissue Cd burdens in hypoxia. Cd exposure led to a significant decrease in tissue glycogen stores, increase in free glucose levels and elevated activity of glycolytic enzymes (hexokinase and aldolase) indicating a greater dependence on carbohydrate catabolism. A compensatory increase in activities of two key mitochondrial enzymes (citrate synthase and cytochrome c oxidase) was found during prolonged hypoxia in control oysters but suppressed in Cd-exposed ones. Cd exposure also resulted in a significant increase in abundance of Vibrio parahaemolyticus and Vibrio vulnificus levels during normoxia and hypoxia, respectively. Overall, Cd- and hypoxia-induced changes in metabolic profile, Cd accumulation and bacterial flora of oysters indicate that these stressors can synergistically impact energy homeostasis, performance and survival of oysters in polluted estuaries and have significant consequences for transfer of Cd and bacterial pathogens to the higher levels of the food chain.