Abstract:The purpose of this study was to assess heavy metal contamination and health risks for residents in the vicinity of a tailing pond in Guangdong, southern China. Water, soil, rice, and vegetable samples were collected from the area in the vicinity of the tailing pond. Results showed that surface water was just polluted by Ni and As, while groundwater was not contaminated by heavy metals. The concentrations of Pb, Zn, Cu, Cd, Ni, and As in the paddy soil exceeded the standard values but not those of Cr. In vegetable soils, the concentration of heavy metals was above the standard values except for Ni and As. Soil heavy metal concentrations generally decreased with increasing distance from the polluting source. Leafy vegetables were contaminated by Pb, Cr, Cd, and Ni, while the non-leafy vegetables were contaminated only by Cr. There was a significant difference in heavy metal concentrations between leafy vegetables and non-leafy vegetables. Almost all the rice was polluted by heavy metals. Diet was the most significant contributor to non-carcinogenic risk, which was significantly higher than the safe level of 1. The total cancer risk was also beyond the safe range (10 −6 -10 −4 ). Results revealed that there is a risk of potential health problems to residents in the vicinity of the tailing pond.

No abstract

Plant male gametogenesis is a coordinated effort involving both reproductive tissues and sporophytic tissues, in which lipid metabolism plays an essential role. Although GDSL esterases/lipases have been well known as key enzymes for many plant developmental processes and stress responses, their functions in reproductive development remain unclear. Here, we report the identification of a rice male sterile 2 (rms2) mutant in rice (Oryza sativa), which is completely male sterile due to the defects in tapetum degradation, cuticle formation in sporophytic tissues, and impaired exine and central vacuole development in pollen grains. RMS2 was map-based cloned as an endoplasmic reticulum-localized GDSL lipase gene, which is predominantly transcribed during early anther development. In rms2, a three-nucleotides deletion and one base substitution (TTGT to A) occurred within the GDSL domain, which reduced the lipid hydrolase activity of the resulting protein and led to significant changes in the content of 16 lipid components and numerous other metabolites as revealed by a comparative metabolic analysis. Furthermore, RMS2 is directly targeted by male fertility regulators Undeveloped Tapetum 1 (UDT1) and Persistent Tapetal Cell 1 (PTC1) both in vitro and in vivo, suggesting that RMS2 may serve as a key node in the rice male fertility regulatory network. These findings shed light on the function of GDSLs in reproductive development and provide a promising gene resource for hybrid rice breeding.

In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.

No abstract