高粱抗蚜研究进展

高粱(Sorghum bicolour)是世界上最重要的粮食、饲料、酿造和能源作物之一, 也是C₄植物研究的模式植物。蚜虫是农业生产上的重要害虫, 几乎危害所有的栽培作物。危害高粱的蚜虫主要包括高粱蚜(Melanaphis sacchari)、麦二叉蚜(Schizaphis graminum)和玉米蚜(Rhopalosiphum maidis)。高粱的抗蚜资源尚不丰富且缺乏深入系统的研究。目前研究较多的是麦二叉蚜的抗性遗传方面, 已定位20个抗性QTLs, 单一QTL对抗性差异贡献率最高可达80.3%, 对高粱蚜和玉米蚜的研究尚需进一步加强。高粱的理化特性与其抗蚜性能相关, 故可与育种实践相结合。高粱和蚜虫(Acyrthosiphon pisum)的全基因组测序工作已经完成, 这将有助于蚜虫-植物间的相互作用关系及植物对蚜虫的抗性机制研究。目前已克隆到2个抗蚜基因, 且多个抗蚜基因(位点)已被定位在染色体上。该文重点综述了上述研究成果并对高粱抗蚜的研究前景进行了展望。     

Risk factors for multiple myeloma: A hospital-based case-control study in Northwest China

BackgroundThe distinctive racial/ethnic and geographic distribution of multiple myeloma (MM) suggests that both family history and environmental factors may contribute to its development.MethodsA hospital-based case–control study consisting of 220 confirmed MM cases and 220 individually matched patient controls, by sex, age and hospital was carried out at 5 major hospitals in Northwest China. A questionnaire was used to obtain information on demographics, family history, and the frequency of food items consumed.ResultsBased on multivariate analysis, a significant association between the risk of MM and family history of cancers in first degree relatives was observed (OR = 4.03, 95% CI: 2.50–6.52). Fried food, cured/smoked food, black tea, and fish were not significantly associated with the risk of MM. Intake of shallot and garlic (OR = 0.60, 95% CI: 0.43–0.85), soy food (OR = 0.52, 95% CI: 0.36–0.75) and green tea (OR = 0.38, 95% CI: 0.27–0.53) was significantly associated with a reduced risk of MM. In contrast, intake of brined vegetables and pickle was significantly associated with an increased risk (OR = 2.03, 95% CI: 1.41–2.93). A more than multiplicative interaction on the decreased risk of MM was found between shallot/garlic and soy food.ConclusionOur study in Northwest China found an increased risk of MM with a family history of cancer, a diet characterized by low consumption of garlic, green tea and soy foods, and high consumption of pickled vegetables. The effect of green tea in reducing the risk of MM is an interesting new finding which should be further confirmed.     

Spatial and temporal determinants of genetic structure in Gentianella bohemica

The biennial plant Gentianella bohemica is a subendemic of the Bohemian Massif, where it occurs in seminatural grasslands. It has become rare in recent decades as a result of profound changes in land use. Using amplified fragment length polymorphisms (AFLP) fingerprint data, we investigated the genetic structure within and among populations of G. bohemica in Bavaria, the Czech Republic, and the Austrian border region. The aim of our study was (1) to analyze the genetic structure among populations and to discuss these findings in the context of present and historical patterns of connectivity and isolation of populations, (2) to analyze genetic structure among consecutive generations (cohorts of two consecutive years), and (3) to investigate relationships between intrapopulational diversity and effective population size (N(e)) as well as plant traits. (1) The German populations were strongly isolated from each other (pairwise F(ST)= 0.29-0.60) and from all other populations (F(ST)= 0.24-0.49). We found a pattern of near panmixis among the latter (F(ST)= 0.15-0.35) with geographical distance explaining only 8% of the genetic variance. These results were congruent with a principal coordinate analysis (PCoA) and analysis using STRUCTURE to identify genetically coherent groups. These findings are in line with the strong physical barrier and historical constraints, resulting in separation of the German populations from the others. (2) We found pronounced genetic differences between consecutive cohorts of the German populations (pairwise F(ST)= 0.23 and 0.31), which can be explained by local population history (land use, disturbance). (3) Genetic diversity within populations (Shannon index, H(Sh)) was significantly correlated with N(e) (R(S)= 0.733) and reflected a loss of diversity due to several demographic bottlenecks. Overall, we found that the genetic structure in G. bohemica is strongly influenced by historical periods of high connectivity and isolation as well as by marked demographic fluctuations in declining populations.     

Association between the polymorphisms of glutathione S-transferase genes and rheumatoid arthritis: A meta-analysis

The glutathione S-transferases (GSTs) are a family of phase II xenobiotic metabolizing enzymes known to be involved in the detoxification and elimination of reactive oxygen species (ROS), thus defending tissues against oxidative stress. Recently, several studies have examined the potential contributions of GSTM1 and GSTT1 gene polymorphisms toward susceptibility to rheumatoid arthritis (RA), but these studies have produced diverse results. To verify the association between GSTM1 and GSTT1 gene polymorphisms and susceptibility to RA, we conducted a meta-analysis of all relevant reports cited in MEDLINE/PubMed before April 2012. A meta-analysis on the association between the GSTM1 polymorphism and RA was performed for 4636 patients with RA and 3916 controls from 8 published studies. In addition, a total of 5 studies involving 3174 RA patients and 2958 controls were considered in the meta-analysis of the association between the GSTT1 polymorphism and RA. No significant association was found between the GSTM1 null genotype and RA susceptibility in all subjects; however, a significant increased risk was found in East Asians. The GSTT1 null genotype was not associated with susceptibility to RA in any study subject. No apparent effect of smoking was found in stratified analysis. The results of our meta-analysis indicated that the GSTM1 null genotype is significantly associated with RA in East Asians alone, indicating that GSTM1 is another non-human leukocyte antigen (non-HLA) susceptibility gene for RA in East Asian populations.     

Accurate Determination of Coulombic Efficiency for Lithium Metal Anodes and Lithium Metal Batteries

Lithium (Li) metal is an ideal anode material for high energy density batteries. However, the low Coulombic efficiency (CE) and the formation of dendrites during repeated plating and stripping processes have hindered its applications in rechargeable Li metal batteries. The accurate measurement of Li CE is a critical factor to predict the cycle life of Li metal batteries, but the measurement of Li CE is affected by various factors that often lead to conflicting values reported in the literature. Here, several parameters that affect the measurement of Li CE are investigated and a more accurate method of determining Li CE is proposed. It is also found that the capacity used for cycling greatly affects the stabilization cycles and the average CE. A higher cycling capacity leads to faster stabilization of Li anode and a higher average CE. With a proper operating protocol, the average Li CE can be increased from 99.0% to 99.5% at a high capacity of 6 mA h cm^?2 (which is suitable for practical applications) when a high‐concentration ether‐based electrolyte is used.     

渭河丰、枯水期底栖动物群落特征及综合健康评价

以渭河为研究范例,分别于丰水期(2011年10月)和枯水期(2012年4月)对渭河全流域范围内45个样点的底栖动物群落进行跟踪调查,并在此基础上应用丰、枯水期底栖动物生物完整性评价指数(B-IBI)对渭河流域水生态系统进行综合健康评价。结果表明,渭河流域底栖动物群落结构具有明显的空间异质性,枯水期底栖动物群落结构单一,物种数量、生物量和香农多样性明显少于丰水期,但单位密度差异不显著。综合健康评价结果表明,渭河上游、洛河中上游地区的健康状况较好,而渭河中下游、泾河全流域及洛河下游地区的健康状况较差。相关分析显示,渭河全流域范围内丰水期和枯水期底栖动物群落的B-IBI得分呈现明显的正相关性,表明在不同水文过程时期,渭河全流域大尺度范围内底栖动物群落的生物完整性特征较为一致。在河流丰、枯水期,底栖动物群落结构的变化趋势并对比分析了渭河流域不同区域水生态系统健康水平差异的原因。     

MsSAMS,a cold stress-responsive gene,provides resistance to environmental stress in T2-generation transgenic plants

The SAMS (S-adenosylmethionine synthetase) gene is known to play an important role in the mechanism of cold resistance, as overexpression of this gene results in phenotypic changes in T₁-generation transgenic plants. Accordingly, this study was conducted to test the expression of the MsSAMS gene in T₂-generation transgenic plants and to investigate the resistance of these plants and the function of the transgene in response to various environmental stresses. For the morphological analysis of T₂-generation transgenic plants overexpressing the MsSAMS gene, observations using scanning electron microscopy (SEM) were performed. T₂-generation transgenic plants were obtained by planting a total of 5 lines, and their characteristics were tested by comparisons with those of the control. SEM revealed that the thickest leaves were produced by the T6 transgenic line—161.24?±?8.05 µm. The number of stomata ranged from 20.00?±?2.65 to 34.00?±?1.00 in the T₂-generation transgenic plants, but the control had more stomata. Resistance to various factors, such as low temperature, drought, and oxidative stress, in the T₂-generation transgenic plants was also confirmed. Under cold-stress conditions, the T6 transgenic line presented the lowest value (22.73%) of ion leakage, and under drought-stress conditions, compared with the control, the transgenic lines presented lower ion leakage after being treated with various concentrations of mannitol. Even under oxidative-stress conditions, the T₂-generation transgenic plants presented ion leakage levels that were 32.91?±?4.24 to 48.33?±?3.54% lower than those of the control after treatment with various concentrations of methyl viologen. Regarding SAMS enzyme activity, as the duration of cold treatment increased, the activity in the transgenic plants tended to decrease and then increase. During 48 h of cold treatment, the control showed a decrease in SAM content, while the T₂-generation transgenic plants presented an increase in SAM content, from 13.58?±?1.04 to 22.75?±?1.95 mg protein/g FW. The results suggest that the MsSAMS gene may be important to the mechanisms of resistance to oxidative and drought stresses in addition to its previously known association with cold resistance. Based on these results, it was suggested that the MsSAMS gene, whose expression is induced by cold stress, can serve as a marker of various responses to environmental stresses, because resistance to cold damage and various environmental stresses are stably inherited in the T₂ generation.