[Association between single nucleotide polymorphism in promoter region of SIRT1 gene and senile degenerative heart valvular disease]

Objective: To investigate the correlation between single nucleotide polymorphisms (SNPs) of SIRT1 gene promoter sequence and senile degenerative heart valvular disease (SDHVD). Methods: A total of 236 SDHVD patients and 285 healthy controls who visited the Affiliated Hospital of Jining Medical University between February 2012 and October 2016 were enrolled. SNPs of SIRT1 gene promoter were detected by Sanger sequencing. Typing and correlation were analyzed by χ(2) test and Logistic regression analysis. Haplotype and linkage disequilibrium were analyzed by Haploview4.2 software and SHEsis online software. The effect of SNPs on the binding of transcription factors to SIRT1 gene promoter was analyzed by electrophoretic mobility shift assay(EMSA). The transcription factors affected by SNPs were predicted by Transfac online software. Results: The frequency distribution of GG genotype of rs3740051 in the SDHVD group was significantly higher than that in the control group (χ(2)=4.855, P=0.028). There was a correlation between GG genotype of the rs3740051 and SDHVD. After adjusting for age, the risk of SDHVD in the carrier of GG genotype was 3.079 times higher than that of AA genotype(OR=3.079, 95%CI: 1.156-8.201, P=0.024). The five SNPs (rs3740051, rs932658, rs35995735, rs3740053 and rs2394443) showed strong linkage disequilibrium(D'>0.8). The haplotype analysis of the five SNPs (haplotype frequency<0 was ignored in the analysis) showed that 11 haplotypes (P<0.05) were formed, and the frequency of *A**C, AA**C, *AG*C, AAG*C, AA*AC, *AGAC and AAGAC in SDHVD group were significantly higher than that in control group (P<0.05, OR>1, 95%CI does not contains 1). EMSA showed that the color of the binding bands incubated by wild type probe and nucleoprotein was darker than that incubated by DNA sequence variation probe and nucleoprotein. Conclusion: The GG genotype of rs3740051 is associated with SDHVD and may be a risk genotype for SDHVD. The haplotype AC (across rs932658 and rs2394443) may be a dangerous haplotype of SDHVD. rs3740051 may affect the occurrence and development of SDHVD by interfering with the binding of FOXC protein to SIRT1 gene promoter.

[Effects of fire intensity on leaf functional traits and functional diversity of Larix gmelinii community]

Fire is an important ecological factor in boreal coniferous forest, which directly affects plant taxonomic and functional diversity and consequently forest succession. We analyzed the changes of soil nutrient contents, leaf functional traits, taxonomic and functional diversity of a Larix gmelinii community under different fire intensity levels (low, medium, heavy). The forest stand had been naturally recovered for 12 years in Yakeshi area. The results showed that fire significantly reduced soil total nitrogen content, but did not affect soil total phosphorus content. Low and medium fire intensities could maintain higher species diversity and functional diversity of the community. Medium fire disturbance significantly increased species diversity of the community, with maximum species richness index, Shannon index, Simpson index and Pielou evenness index. Fire disturbance reduced functional richness and functional divergence of the community, which were the largest in medium and low fire intensity respectively (except unburned). Functional evenness and Rao qua-dratic entropy index increased after forest fire disturbance, and the largest was in the low intensity burned area. With the increases of fire intensity, leaf dry matter content, leaf tissue density and leaf total phosphorus content showed a significantly increased trend, while specific leaf area, leaf water content, leaf total nitrogen content and leaf N:P showed the trend unburned ＞ medium fire ＞ low fire ＞ heavy fire, leaf thickness increased first and then decreased. Fire intensity had significant effects on leaf functional traits and functional diversity of forest community. Moderate fire distur-bance could promote forest restoration.

Genetic diversity in the northernmost Oryza rufipogon populations estimated by SSR markers

To estimate genetic diversity of the residual northern populations of Oryza rufipogon, a total of 232 individuals from six populations were analyzed using microsatellites (SSRs). The O. rufipogon populations with different status included three from Dongxiang (Jiangxi Province) and three from Chaling (Hunan Province) in China. The 23 rice SSR primer pairs selected from the RiceGenes Database detected a total of 115 alleles, indicating that all the SSR loci were polymorphic in this study. The total gene diversity was 0.919 in the six O. rufipogon populations, and the Donxiang populations showed higher diversity than the Chaling populations. More significant genetic differentiation and less gene flow were found among the Dongxiang populations than those from Chaling. The two putative introgressed populations showed relatively high genetic variation. One in situ conserved population from Dongxiang had the lowest level of genetic diversity. The re-introduced population from Chaling restored about 90% of the genetic variation, compared with the original source population. It is concluded from these results that a relatively high level of genetic variation resided in the northern O. rufipogon populations and continued efforts of conservation of these populations are needed; and that the conservation of some Chaling and Dongxiang populations has been effective in preventing gene flow from cultivated rice. Introgression of cultivated rice demonstrated significant impacts on genetic variability of the O. rufipogon populations, and should be carefully considered in conserving this wild rice. This study also suggested that re-introduction to its original habitats is an effective approach to restore O. rufipogon populations.