Genetic consequences of group living in Mongolian gerbils

Social behavior can shape the local population genetic structure of mammals. Group living can increase pairwise genetic relatedness of mammals at a local level but differentiate the genetic structure at a population level through offspring philopatry and nonrandom mating. Our study aimed to test the hypothesis that social groups of Mongolian gerbils (Meriones unguiculatus) would consist of genetically related individuals due to offspring philopatry and would have distinct genetic structures because of restricted gene flow among social groups and nonrandom mating. We genotyped 327 wild gerbils, live captured from 28 social groups in Inner Mongolia, China, using nine microsatellite loci. The within-group pairwise genetic relatedness coefficient averaged 0.28 ± 0.14 (standard deviation), whereas the average pairwise genetic relatedness coefficient of the whole gerbil population was 0.0 ± 0.2. Additionally, the value of the global F statistic (F(st)) was 0.21, suggesting a substantial genetic differentiation among social groups of Mongolian gerbils. The Bayesian clustering divided the 327 gerbils into 23 distinct genetic clusters. Therefore, our results show that high within-group genetic relatedness and among-group genetic differentiation are the genetic consequences of group living in social mammals because of restricted gene flow, female philopatry, and nonrandom mating within social groups.     

A simultaneous extraction method for metabolome and lipidome and its application in cry1Ac and sck-transgenic rice leaf treated with insecticide based on LC–MS analysis

Abiotic stress caused by insecticide treatment is an interesting and challenging topic in plant research. Here a simultaneous extraction method with methyl tert-butyl ether for metabolomics and lipidomics analysis by using rapid resolution liquid chromatography quadrupole time-of-flight mass spectrometry was developed and validated. The extraction efficiency of lipidome and metabolome based on the current developed method showed an obvious improvement compared with literatures. About 300 metabolites were identified in rice leaf. Method validation was performed and analytical properties including the linearity (R², 0.991–1.000), repeatability (over 87 % peaks with CV < 20 % accounting for over 92 % of total response) and recovery (74.4–119.6 %) were satisfactory. The method was then applied to investigate time-course changes caused by insecticide treatment in transgenic rice with cry1Ac and sck genes and its wild counterpart. Antioxidants including ferulic acid and sinapic acid were down-regulated at 24 h after insecticide treatment. Signaling metabolites including salicylic acid and nicotinamide adenine dinucleotide were significantly up-regulated at 12–24 h after treatment in transgenic rice. More flavonoids were significantly changed in transgenic plants. Results indicated that gene transformation affected the metabolic response of rice to insecticide stress.     

Study of polar metabolites in tobacco from different geographical origins by using capillary electrophoresis–mass spectrometry

Many metabolites in plant are highly polar and ionic. Their analysis using gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry can be problematic. Therefore a capillary electrophoresis–mass spectrometry (CE–MS) method with charge-driven separation characteristic was developed to investigate polar metabolites in tobacco. To obtain as many features as possible, extraction of polar metabolites was optimized by the design of experiments and evaluated by univariate statistics. Method validation was carried out to evaluate the analytical characteristics including calibration curve, precision, sample stability and extraction reproducibility. The developed method was successfully applied in studying 30 tobacco leaves obtained from Yunnan and Guizhou provinces in China. A total of 154 polar metabolites were identified based on available database. Multivariate pattern recognition clearly revealed the metabolic differences between the two geographic areas and 43 significantly different metabolites were defined by the non-parametric hypothesis test (Mann–Whitney U test) and false discovery rate. Some key metabolites involved in photosynthesis such as ribulose 1,5-disphosphate, fructose 1,6-diphosphate, glycine, betaine, GABA and serine were found to be susceptible to environmental conditions. This study shows that the metabolic profiling based on CE–MS can clearly discriminate tobacco leaves of different geographical origins and understand the relationship between plant metabolites and their geographical origins.     

Assignments of human integrin α1I domain in the apo and Mg2+ bound states

The α1β1 integrin receptor binds to its main extracellular ligand, collagen, through an inserted domain in its α-subunit called the αI domain (αI). αI contains a metal binding site that allows collagen to coordinate to the domain through a divalent metal ion. Here we report the backbone assignments of the apo and Mg²⁺ bound state of the isolated human α1I and the chemical shift changes resulting from metal coordination.     

Effect of Mixed Transplantation of Autologous and Allogeneic Microskin Grafts on Wound Healing in a Rat Model of Acute Skin Defect

The treatment of extensive thermal injuries with insufficient autologous skin remains a great challenge to burn surgeons. In this study, we investigated the influence of the ratio of autologous and allogeneic tissue in mixed microskin grafts on wound healing in order to develop an effective method for using limited donor skin to cover a large open wound. Four different mixtures were tested: autologous microskin at an area expansion ratio of 10∶1 with allogeneic microskin at an area expansion ratio of 10∶1 or 10∶3 and autologous microskin at an expansion ratio of 20∶1 with allogeneic microskin at an expansion ratio of 20∶3 or 20∶6. Wound healing, wound contraction, and integrin β1 expression were measured. Mixed microskin grafting facilitated wound healing substantially. The mixture of autologous microskin at an expansion ratio of 10∶1 with the same amount of allogeneic microskin achieved the most satisfactory wound healing among the 4 tested mixtures. Histological examination revealed the presence of obviously thickened epidermis and ectopic integrin β1 expression. Keratinocytes expressing integrin β1 were scattered in the suprabasal layer. Higher levels of integrin β1 expression were associated with faster wound healing, implying that ectopic expression of integrin β1 in keratinocytes may play a pivotal role in wound healing. In conclusion, this study proves that this new skin grafting technique may improve wound healing.     

Association Between a Single Nucleotide Polymorphism in the TP53 Region and Risk of Ovarian Cancer

TP53 is known as a tumor suppressor gene involved in cell cycle regulation. Many previous epidemiological and clinical studies have evaluated the effects of rs1042522 polymorphism on risk of ovarian cancer. But the results are conflicting and heterogeneous. The primary objective of this study was to examine whether rs1042522 polymorphism is associated with ovarian cancer risk. We performed a comprehensive meta-analysis of 19 case–control studies that analyzed rs1042522 polymorphism in ovarian cancer risk. Odds ratios (ORs) were calculated using distinct genetic models. Heterogeneity between studies was detected by the χ²-based Q test. Additional analyses such as sensitivity analyses and publication bias were also performed. The rs1042522 polymorphism was not overall associated with ovarian cancer risk. But there was a borderline association in the heterozygote model (OR = 1.09, 95 % CI 0.99–1.21). Similar effects were observed in the subgroup of Caucasian population (the heterozygote model: OR = 1.11, 95 % CI 1.00–1.24). No significant heterogeneity and publication bias were revealed in this meta-analysis. This study provides statistical evidence that TP53 rs1042522 polymorphism may play a role in modulating risk of ovarian cancer. This observation requires further analysis of a larger study size.     

基于历史参照系的三江源区径流调节功能及变化评估

以20世纪70年代植被类型图作为参照生态系统,采用径流量和径流系数作为径流调节功能的表征指标,建立了基于历史参照系的三江源区径流调节功能评估模型,以参照系径流系数与实际径流系数的比值作为径流系数质量指数,分析了2000-2017年三江源区生态系统径流调节功能参照值、现状值及变化量的时空变化规律。结果表明：2000-2017年,三江源区多年平均径流量为495.15亿m³,地表径流量为96.64亿m³,参照系条件下多年平均径流量为468.37亿m³,地表径流量为68.60亿m³。相比参照系,三江源区生态系统的径流蓄纳能力降低,总径流量和地表径流量均明显增加。空间上,基于参照系和实际生态系统的多年平均径流量表现为东南高西北低的空间分布特征,地表径流量则呈西部高东部低的空间分布特征。从时间变化看,实际径流和参照系径流的差别率在4%-9%之间,实际地表径流和参照系地表径流的差别率在22%-58%之间。径流系数质量指数得分显示,2000-2017年,三江源区径流系数质量指数平均得分为98.63,地表径流系数质量指数平均得分为96.98,两者均呈现先降低后增加的趋势,地表径流系数质量指数变化更为明显。2000-2017年,各县（镇）径流系数和地表径流系数质量指数得分具有较大差别,但各县（镇）得分变化均不明显,变化率分别在-1.95%-0.71%和-0.35%-1.90%之间。通过建立基于历史生态系统的评估参照系,定量评估了三江源区参照系和实际条件下的径流变化过程,实现了不同时间、不同区域生态系统径流调节功能的可比较,可对量化生态系统恢复进程提供支撑。