Brodersenphelps9601

Human activities have greatly altered terrestrial carbon (C) dynamics associated with vegetation cover and land use changes, thereby influencing the C sink in downstream ecosystems. However, the transport and preservation of organic C from soils that experience serious erosion in the karst area are scarce, particularly at catchment scales. In this study, chemical characteristics of organic matter (OM) isolated from the topsoil, overlying water, and lake sediments, as well as subsequent source identification, were inferred from the molecular, spectroscopic, and carbon isotopic (δ13C) signatures in a typical karst catchment, Southwestern China. The results indicated that the elemental compositions of the calcareous soil and paddy soil significantly differed from the yellow soil. High similarities existed in the fluorescence spectra of humic substances (HS) extracted from the front two soil types with those of lake sediments, indicating the homogeneous nature of OM molecular structure. The C/N ratios of six dissolved OM fractions and sedimentary HS along with δ13C values consistently reflected the primary terrestrial source. It was estimated to account for 60% of total organic C in sedimentary OM by end-member mixing modeling in accordance with soil erosion intensity and large recharge coefficient of this catchment. The evolution of soil loss and lake productivity can be well deduced from sediment records of organic C content, C/N ratio, and the specific information of HS. This research highlighted that the composition, source, and fate of OM in the karst lake was mainly dominated by the terrestrial C flux, rather than in-lake production. Furthermore, soil type and erosion intensity have significant effects on the nature of eroded OM and ultimate preservation.The present study was carried out to clarify the effect of different doses of melatonin on some reproductive hormones, serum total antioxidant, histopathological examination, lipid peroxidation, and antioxidant parameters in liver, kidney, heart, and testis tissues in induced-hyperthyroidism (HT) male rat model. A total of 75 mature male Wistar rats were equally allocated into five groups; control groups were daily I/P injected with distilled water containing 4 M ammonium hydroxide in methanol and 1% absolute ethanol; on hyperthyroidism model group, rats received daily I/P injection of L-thyroxine (0.2 mg/kg body weight). In melatonin-treated groups, rats were injected with the same dose of L-thyroxine followed by I/P injection of melatonin (1, 5, or 10 mg/kg, respectively) for 21 days. The hyperthyroidism group showed significant increase in serum thyroxine (T4), triiodothyronine (T3), and testosterone levels and a significant decrease in the levels of thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and serum total antioxidants capacity, with a significant decrease in superoxide dismutase (SOD) activity and glutathione reductase (GSH) content with a significant increase in malondialdehyde (MDA) concentration in all examined tissues. While, melatonin co-treatment to HT groups partially counteracted the effect of hyperthyroidism by decreasing serum T4 and T3 levels and increasing serum TSH. In addition, melatonin could decrease serum levels of FSH, LH, and testosterone, as well as it could increase serum total antioxidants capacity, SOD activity, and GSH content and decreased MDA concentration in all examined tissues. Additionally, melatonin could amend the histopathological alterations in the examined tissues of hyperthyroid rats but not the testicular tissue. It is concluded that melatonin has a protective role against the hyperthyroidism-induced oxidative damage but cannot ameliorate the reproductive disorders in male rat model.Toxicity due to heavy metals (HM), specifically mercury (Hg), arsenic (As), lead (Pb), and cadmium (Cd) remains a challenge to scientists till date. This review gives insights into natural antidotes for the management and prevention of HM toxicity. Various databases such as PubMed, Embase, and Science Direct were searched for available facts on natural antidotes and their commercial products against HM toxicity till date. Toxicity owing to such metals needs prevention rather than therapy. find more Natural antidotes, fruits and vegetables, rich in antioxidant are the answers to such toxicities. Synthetic chelators impart a major drawback of removing essential metals required for normal body function, along with the toxic one. Natural antioxidants are bestowed with scavenging and chelation properties and can be alternative for synthetic chelating agents. Natural compounds are abundantly available, economic, and have minimal side effects when compared with classical chelators. Prevention is better than cure and thus adding plentiful vegetables and fruits to our diet can combat HM toxicity-related illness. Graphical abstract.Dissimilatory nitrate reduction to ammonium (DNRA) is an important process of nitrate reduction in the environment. The distribution of DNRA bacteria and the relationships with environmental factors in multistage constructed wetland were investigated in this study. The quantitative real-time polymerase chain reaction analysis showed that the abundance of DNRA bacteria at all sites ranged from 2.10 × 1010 to 1.10 × 1011 copies/g of dry sediments. The Anaeromyxobacter (belong to Deltaproteobacteria) was the most abundant DNRA bacteria at all sites. The Geobater known as DNRA bacteria was also identified in this study. The abundances of DNRA bacteria, denitrifying bacteria, and anammox bacteria were conspicuously negatively correlated with Eh and positively correlated with the NO3--N removal efficency by statistical analysis.Soil contamination caused by long-term application of metsulfuron-methyl and tribenuron-methyl has become an issue of increasing concern. In our previous study, strain Chenggangzhangella methanolivorans CHL1, capable of efficiently degrading sulfonylurea herbicides, was isolated. Here, the bioremediation potential of strain CHL1 was assessed for soil polluted with metsulfuron-methyl or tribenuron-methyl in a pot experiment. The growth parameters of waxy maize were measured on day 21 of the pot experiment. Additionally, the residues of metsulfuron-methyl and tribenuron-methyl in soils were analyzed, and the soil microbial community was investigated using a phospholipid fatty acids (PLFAs) method on days 1, 7, 14, and 21. The results indicated that strain CHL1 greatly accelerated the degradation of metsulfuron-methyl and tribenuron-methyl in soils. The degradation rates in the treatments inoculated with strain CHL1were all more than 91% after 7 days, significantly higher than the 25-36% degradation measured in non-inoculated treatments.