Effects of soil properties on heavy metal bioavailability and accumulation in crop grains under different farmland use patterns.

Mining activities have increased the accumulation of heavy metals in farmland soil and in food crops. To identify the key soil properties influencing heavy metal bioavailability and accumulation in food crops, 81 crop samples and 81 corresponding agricultural soil samples were collected from rape, wheat, and paddy fields. Heavy metal (copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), iron (Fe), and manganese (Mn)) concentrations in soils and rape, wheat, rice grains were determined using inductively coupled plasma atomic emission spectroscopy, and soil physicochemical properties (pH, organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium (AK)) were analyzed. Soil extractable metals were extracted using various single extractants (DTPA, EDTA, NH4OAc, NH4NO3, and HCl). The average concentrations of Cu, Zn, Pb, Cd, and Mn in the soil samples all exceeded the local geochemical background value (background values of Cu, Zn, Pb, Cd, and Mn are 43.0, 81.0, 28.5, 0.196, and 616 mg/kg, respectively), and Cd over-standard rate was the highest, at 98%. Furthermore, soil total Cd concentrations (0.1-24.8 mg/kg) of more than 86% of the samples exceeded the soil pollution risk screening value (GB 15618-2018). The sources of Cu, Zn, Pb, Cd, and Mn in soils were mainly associated with mining activities. The key factors influencing heavy metal bioavailability were associated with the types of extractants (complexing agents or neutral salt extractants) and the metals. Cd and Pb concentrations in most wheat and rice grain samples exceeded the maximum allowable Cd and Pb levels in food, respectively, and Cd concentrations in approximately 10% of the rice grain samples exceeded 1.0 mg/kg. Furthermore, rice and wheat grains exhibited higher Cd accumulation capacity than rape grains, and despite the high soil Cd concentrations in the rape fields, the rape grains were safe for consumption. High soil pH and AK restricted Cd and Cu accumulation in wheat grains, respectively. Soil properties seemed to influence heavy metal accumulation in rice grains the most.

Interactions between heavy metals and other mineral elements from soil to medicinal plant Fengdan (Paeonia ostii) in a copper mining area, China.

In order to analyze the interaction relationship between heavy metals and other mineral elements during the processes of absorption and translocation by plant grown on heavy metal-contaminated area, the concentrations of Cu, Zn, Mn, Cd, Pb, Ca, Mg, Fe, and K in the medicinal plant Paeonia ostii T. Hong et J. X. Zhang and its rhizospheric soil were determined, which grow around an abandoned copper tailings reservoir in Tongling City, China. Geo-accumulation index (Igeo) calculation indicated that Cu and Pb are the main pollution elements in the rhizospheric soil. Moreover, the Cu and Pb concentrations in the cortex moutan of P. ostii exceeded the maximum permissible limits for food product safety. The bioaccumulation factor values of the tested metals in plant roots were found < 0.50, with the exception of Ca (maximum 5.99). The translocation factor values of detected heavy metals Cd and Pb were more than 1.00, which indicated that P. ostii could be considered a potential accumulator plant for Cd and Pb. Significant positive correlations including Cu-Cd, Cu-Zn, Cu-Pb, Cd-Zn, Cd-Fe, Cd-Fe, Zn-Pb, Pb-Fe, Mn-Fe, and Ca-Mg in the cortex moutan and Cu-Zn, Cu-Fe, Zn-Mg, Zn-Fe, and Mn-K in the leaves were observed (P < 0.05). Significant positive correlation between Cu, Zn, Mg, and Fe was also confirmed in the processes of absorption and translocation from the soil to plant (P < 0.05), which evidenced that synergistic element interactions of the essential elements Cu, Zn, Mg, and Fe are a result of the similarity in their ionic radii and octahedral coordination geometry.

Comparative Genomics Uncovers the Genetic Diversity and Synthetic Biology of Secondary Metabolite Production of Trametes.

The carbohydrate-active enzyme (CAZyme) genes of Trametes contribute to polysaccharide degradation. However, the comprehensive analysis of the composition of CAZymes and the biosynthetic gene clusters (BGCs) of Trametes remain unclear. Here, we conducted comparative analysis, detected the CAZyme genes, and predicted the BGCs for nine Trametes strains. Among the 82,053 homologous clusters obtained for Trametes, we identified 8518 core genes, 60,441 accessory genes, and 13,094 specific genes. A large proportion of CAZyme genes were cataloged into glycoside hydrolases, glycosyltransferases, and carbohydrate esterases. The predicted BGCs of Trametes were divided into six strategies, and the nine Trametes strains harbored 47.78 BGCs on average. Our study revealed that Trametes exhibits an open pan-genome structure. These findings provide insights into the genetic diversity and explored the synthetic biology of secondary metabolite production for Trametes.

Pterostilbene Attenuates Experimental Atherosclerosis through Restoring Catalase-Mediated Redox Balance in Vascular Smooth Muscle Cells.

Atherosclerosis, the major risk of cardiovascular events, is a chronic vascular inflammatory disease. Pterostilbene is a naturally occurring dimethylated analogue of resveratrol and has recently been demonstrated to be beneficial against cardiovascular diseases. However, the underlying mechanisms of pterostilbene on atherosclerosis remain elusive. Experimental atherosclerosis was induced by a high-fat diet (HFD) in apolipoprotein E knockout (ApoE-/-) mice. Pterostilbene was administered intragastrically for 16 weeks. We found that pterostilbene significantly attenuated thoracic and abdominal atherosclerotic plaque formation in HFD-fed ApoE-/-mice, accompanied by modulated lipid profiles and reduced production of proinflammatory cytokines (including IL-6, IFN-γ, and TNF-α). In addition, pterostilbene restored vascular redox balance in thoracic and abdominal aorta, evidenced by enhanced catalase (CAT) expression and activities, and decreased malondialdehyde and H2O2 production. Notably, pterostilbene specifically induced CAT expression and activities in the vascular smooth muscle cells (VSMCs) of thoracic and abdominal aorta. In vitro, pterostilbene markedly promoted the expression and activity of CAT and decreased ox-low-density lipoprotein (LDL)-mediated VSMC proliferation and intracellular H2O2 production, which was abolished by CAT siRNA knockdown or inhibition. Pterostilbene-induced CAT expression was associated with inhibition of Akt, PRAS40, and GSK-3ß signaling activation and upregulation of PTEN. Our data clearly demonstrated that pterostilbene exerted an antiatherosclerotic effect by inducing CAT and modulating the VSMC function.

Ecological and health risks of heavy metal on farmland soils of mining areas around Tongling City, Anhui, China.

To investigate and assess heavy metal contamination on the farmland soils of a typical mining city, the concentrations of Cu, Cd, Zn, Pb, As, and Cr were analyzed from four mining areas (Tongguan District (TGD), Shunan Town (SAT), Tianmen Town (TMT), and Zhongmin Town (ZMT)) and two control areas (Xilian Township (XLT), Donglian Township (DLT)) in Tongling City, China. The total metal concentrations in the soils were in the following order: Cd ˂ As ≤ Pb ˂ Cu ˂ Cr ≤ Zn. Total metal concentrations in the soils of mining areas were significantly higher than those of the control areas (P < 0.05). According to the Chinese Environmental Quality Standard for Soils (GB 15618-1995) and geo-accumulation index (Igeo), Cd and As pollution in the farmland soils of the mining areas was the most severe, followed by Cu. The Igeo values of soil heavy metals of TGD and SAT were the most highest, followed by those of TMT and ZMT. The health risk quotient (HQ) of heavy metals in the soils showed as follows: HQAs ˃ HQPb ˃ HQCr ˃ HQCd ˃ HQCu ˃ HQZn, and the total average daily exposed dose (non-carcinogenic risk) of As was the highest except that of Cd. The contribution rate of carcinogenic risk index (CR) to total carcinogenic risk index (TCR) of As and Cd in the topsoil for adults was 99.91% and 0.09% respectively, and the value for children was 99.87% and 0.13%. The CR and TCR of As in the farmland of mining areas were greater than 10-4, which showed the carcinogenic risk is an intolerable range for both adults and children. According to the results of the present study, it can help the local people know the pollution of heavy metals in farmland and adopt the best suitable agriculture practices.

Assessment of trace metal bioavailability in garden soils and health risks via consumption of vegetables in the vicinity of Tongling mining area, China.

Environmental pollution due to mining activities has been reported in many countries. In this study, 283 vegetable and 44 corresponding garden soil samples were collected in the vicinity of the Tongling mining area, China. The aim was to evaluate the bioavailability of trace metals (Cu, Zn, Pb and Cd) to vegetables by comparing different methods (trace metals in DTPA, EDTA, HCl, NH(4)NO(3), NH(4)OAC aqueous solutions and total metals in garden soils), and assess the potential health risks of trace metals to the local population via vegetable consumption. The results showed that the mean values of total Cu and Cd in the soil samples exceeded the Grade II national standard in China. Average concentrations of Cd and Pb in some vegetable samples were higher than the maximum permissible concentration in China. The transfer factors for trace metals in different vegetables showed a trend of Cd>Zn>Cu> Pb. Asteraceae vegetables had stronger metal uptake than Liliaceae. The total target hazard quotient (THQ) value was greater than 1, suggesting that trace metals in vegetables could present some potential health risks. The effectiveness of the studied methods for estimating soil metal bioavailability was generally dependent on the particular metal and vegetable species. Overall, 1.0M NH(4)OAC provided the best estimate of Cd and Zn bioavailability in multi-elemental contaminated soils. None of the studied soil metal extraction methods appeared suitable for measuring Cu or Pb bioavailability, especially for Pb, which showed almost no correlation between metal concentration in soil and vegetables.