[Pb, Zn accumulation and nutrient uptake of 15 plant species grown in abandoned mine tailings].

Vegetation restoration field test was carried out in the abandoned lead-zinc tailings for 3 years. The study showed that accumulation of lead (Pb), zinc (Zn) and nutrient uptake differed with plant species and organs, heavy metals, and planting time. Pb was mainly accumulated in tree roots, and its content distribution in tree organs was generally in the order of roots > leaves > stems. But Zn concentrations in leaves of several tree species were higher than those in roots and stems. Within the tested 15 species, Cercis Canadensis had the highest concentrations of Pb and Zn in roots (1 803 and 2120 mg x kg(-1), respectively). Rhus chinensis had the highest Pb concentration in stems and leaves (280 and 546 mg x kg(-1), respectively) and Zn concentration (1 507 mg x kg(-1)) in leaves. Zn concentration in stems and leaves of Salix matsudana (729 and 1 153 mg x kg(-1), respectively) were the highest. Among the tested 15 species, TF values for Pb of Liquidambar formosana, Medicago sativa, and for Zn of Salix matsudana, Rhus chinensis, Medicago sativa were higher than 1. BCF values for Pb were all lower than 0.17, while that for Zn were all lower than 0.44. The N contents in nitrogen-fixing plants, P contents in Rhus typhina and Ailanthus altissima, and K content in Nerium indicum were significantly higher than those in other plants. With the increase of planting time, concentrations of heavy metal in plant body increased significantly; however the inverse trend were observed in nutritional element content. The species have higher metal accumulation capacity, such as Rhus chinensis, Salix matsudana and those nitrogen-fixing plants have higher tolerance to metal contamination and nutrient deficiency, such as Amorpha fruticosa, Medicago sativa, Lespedeza cuneata, and Alnus cremastogyne, they were suitable as the phytostabilizers in abandoned mine tailings.

Natural selection on EPAS1 (HIF2alpha) associated with low hemoglobin concentration in Tibetan highlanders.

By impairing both function and survival, the severe reduction in oxygen availability associated with high-altitude environments is likely to act as an agent of natural selection. We used genomic and candidate gene approaches to search for evidence of such genetic selection. First, a genome-wide allelic differentiation scan (GWADS) comparing indigenous highlanders of the Tibetan Plateau (3,200-3,500 m) with closely related lowland Han revealed a genome-wide significant divergence across eight SNPs located near EPAS1. This gene encodes the transcription factor HIF2alpha, which stimulates production of red blood cells and thus increases the concentration of hemoglobin in blood. Second, in a separate cohort of Tibetans residing at 4,200 m, we identified 31 EPAS1 SNPs in high linkage disequilibrium that correlated significantly with hemoglobin concentration. The sex-adjusted hemoglobin concentration was, on average, 0.8 g/dL lower in the major allele homozygotes compared with the heterozygotes. These findings were replicated in a third cohort of Tibetans residing at 4,300 m. The alleles associating with lower hemoglobin concentrations were correlated with the signal from the GWADS study and were observed at greatly elevated frequencies in the Tibetan cohorts compared with the Han. High hemoglobin concentrations are a cardinal feature of chronic mountain sickness offering one plausible mechanism for selection. Alternatively, as EPAS1 is pleiotropic in its effects, selection may have operated on some other aspect of the phenotype. Whichever of these explanations is correct, the evidence for genetic selection at the EPAS1 locus from the GWADS study is supported by the replicated studies associating function with the allelic variants.

[Investigation of single nucleotide polymorphisms in the promoter region of mannan-binding lectin gene in Bais, Uars and Lahus ethnics from China].

AIM: To investigate the single nucleotide polymorphisms(SNP) in the promoter region of mannan-binding lectin (MBL) gene in Bais, Uars and Lahus ethnics. METHODS: 71, 73 and 94 blood samples were obtained from Bais, Uars and Lahus subjects, respectively from Yunnan province. Genomic DNA was isolated from leucocytes. Polymorphism alleles -550(G/C, named H/L alleles), -220(G/C, X/Y alleles) and +4(C/T, P/Q alleles) in the promoter region of MBL gene were detected by sequence-specific primer-PCR and molecular beacon real-time PCR, and the frequencies of haplotypes and genotypes were analyzed. RESULTS: The frequencies of genotypes in Bais, Uars and Lahus ethnics were as follows: LYP/LYP 4(5.6%), 4(5.5%)and 2(2.1%); HYP/LYQ 6(8.5%), 11(15.1%) and 12(12.8%); LYP/LYQ 21(29.6%), 14(19.2%) and 51(54.3%); LXP/LXP 1(1.4%), 2(2.7%)and 0,LYQ/LYQ 10(14.1%); 14(19.2%), 7(7.4%), LXP/LYQ 10(14.1%), 13(17.8%) and 15(16.0%); HYP/LYP 4(5.6%), 3(4.1%) and 4(4.3%); HYP/LXP 3(4.2%), 1(1.4%) and 0; HYP/HYP 12(16.9%), 11(15.1%) and 3(3.2%). CONCLUSION: The distribution of alleles L/H is statistically different among Uars, Bais and Larhus(P<0.01), while X/Y and P/Q are not statistically significant(P>0.05). All studied haplotypes and genotypes are statistically different among the 3 ethnics(P<0.01). Genotypes LYP/LYQ and LXP/LYQ are common in all the 3 ethnics.