Concentrations of copper, zinc and manganese in Tree Sparrow (Passer montanus) at Jixi, Heilongjiang Province, China

Concentrations of copper （Cu）, zinc （Zn） and manganese （Mn） were measured in four tissues of Tree Sparrow （Passer montanus） from three sites in Heilongjiang province, China, during four seasons. Among the four measured tissues （primary feathers, liver, heart, and pectoral muscle）, the highest concentrations were found in feathers （Zn） or liver （Cu and Mn）, and the lowest concentrations were in muscle, except Cu. For Mn, mean concentrations of the birds from the three study sites were, in decreasing order： Didao mining area （DMA） 〉 urban district of Jixi （UDJ） 〉 Phoenix Mountain national nature reserve （PMR, the reference site）, but not for Zn and Cu. There were significant differences between metal concentrations at the three sites, but differences were not significant for Mn （in muscle and feathers） and Cu （in feathers）. For most elements, the mean concentrations were greatest in summer.

Compositional Shifts in Ammonia-Oxidizing Microorganism Communities of Eight Geographically Different Paddy Soils —Biogeographical Distribution of Ammonia-Oxidizing Microorganisms

Soil nitrification is mediated by ammonia-oxidizing archaea (AOA) and bacteria (AOB), which occupy different specialized ecological niches. However, little is known about the diversification of AOA and AOB communities in a large geographical scale. Here, eight paddy soils collected from different geographic regions in China were selected to investigate the spatial distribution of AOA and AOB, and their potential nitrification activity (PNA). The result showed that the abundance of AOA was predominant over AOB, indicating that the rice fields favor the growth of AOA. PNA highly varied from 0.43 to 3.57 μg NOX-N·g·dry·soil·h-1, and was positively related with soil NH3 content, the abundance of AOA community, and negatively related with the diversity of AOB community (P amoA genes revealed remarkable differences in the compositions of AOA and AOB community. Phylogenetic analyses of amoA genes showed that Nitrosospiracluster-3-like and Nitrosomonas cluster 7-like AOB extensively dominated the AOB communities, and 54d9-like AOA within the soil group 1.1b predominated in AOA communities in paddy soils. Redundancy analysis suggested that the spatial variations of AOA community structure were influenced by soil TN content (P < 0.01), while no significant correlation between AOB community structure and soil properties was found. Findings highlight that ammonia oxidizers exhibit spatial variations in complex paddy fields due to the joint influence of soil variables associated with N availability.

The Influence of SelW on GSH and GPx after Post-Transcriptional Gene Silencing in Mouse Skeletal Muscle Cells

The expression of Selenoprotein W(SelW)in C2C12 skeletal muscle cells was specifically decreased to examine its influence on the amount of glutathione(GSH)and the activity of glutathione peroxidase(GPx).SelW knock-down was performed by RNA interference(RNAi)in cultured muscle cells and verified by Real-time PCR and Western blotting.In addition,cell viability,GSH content and GPx activity were assayed.The results showed that the mRNA level and protein expression of SelW were decreased successfully by 71.9%and 68.8%relative to control values,cell viability decreased by 21.5%,GSH increased by 29.76%,and GPx increased by 47.58%.WST assay showed that compared with blank control,the value of positive group dropped 21.5%;In GSH and GPx assay,compared with blank control the positive group increased29.76%and 47.58%separately.In conclusion,SelW knock-down by RNAi caused significant cytotoxity in skeletal muscle cells and led to compensatory increases in GSH content and GPx activity.These findings are consistent with the suggestions from bioinformatics indicating an antioxidative role for SelW in skeletal muscle cells.