SNP deserts of Asian cultivated rice: genomic regions under domestication

When performing a genome‐wide comparison between indica (93‐11) and japonica (Nipponbare), we find 8% of the genome, which have an extremely low SNP rate (< 1 SNP/kb). Inside these ‘SNP deserts’, experimentally confirmed genes show increased K_a/K_s that indicate adaptive selection. To further elucidate this connection, we survey the level and pattern of genetic variation in both cultivated and wild rice groups, using 155 noncoding regions located within SNP deserts. The results suggest that cultivated rice has greatly reduced genetic variation within SNP deserts as compared to either the nondesert or corresponding genomic regions in wild rice. Consistent with this reduction in genetic variation, we find a biased distribution of derived allele frequency in the cultivated group, indicative of positive selection. Furthermore, over half of the confirmed, domestication‐related genes are found within SNP deserts, also suggesting that SNP deserts are strongly related to domestication, and might be the key sites in the process of domestication.     

Doxy对大鼠动脉内膜损伤后MMP-1表达影响的研究

目的:观察动脉内膜损伤后基质金属蛋白酶-1(MMP-1)的表达变化,探讨Doxy和MM-1对动脉内膜损伤后再狭窄的影响.方法:建立大鼠颈总动脉损伤模型,治疗组用多西环素30mg·kg-1·d-1干预,免疫组化测定损伤动脉中MMP-1的表达,弹力纠维染色观察损伤动脉内膜面积、管腔面积的情况.结果:①MMP-1阳性指数于损伤后3d表达最高,以后逐渐减少,28d时达最低值,Doxy治疗组MMP-1表达的阳性指数3d,7d,14d均低于手术组(P＜0.01),而28d则与手术组无明显差别(P＞0.05).②内膜面积自术后7 d开始增加,28d后达最高值,管腔面积自术后7 d开始减少,28d后达最低值.Doxy治疗组14 d及28 d内膜面积明显小于手术组,管腔面积明显大于手术组,具有显著差异(P＜0.01).结论:动脉内膜损伤后MMP-1强烈表达,Doxy可以显著降低血管损伤后前2周MMP-1的表达,提示它可能防治动脉内膜损伤后再狭窄而不需长期给药.     

独行菜种子转录组的高通量测序及分析

独行菜种子为我国传统常用中药,从中已提取出多种药用活性成分,但目前尚不清楚其次级代谢过程中这些活性物质合成的遗传基础。采用Illumina Hiseq^TM 2000高通量测序平台对独行菜种子转录组进行测序,经de novo组装后获得40 303条unigene。进一步利用六大公共数据库进行同源比对,注释了27 935条unigene。研究发现,534个基因参与了独行菜次生物质的合成和代谢,其中在芥子苷、黄酮类和芪类化合物生物合成途径中的unigene分别有4个、19个和69个,在苯丙氨酸代谢途径中的unigene有92个。这些基因可能参与独行菜种子药性活性物质的生物合成,并分析获得了参与上述合成代谢途径的13个关键基因的同源序列。另外,从转录组序列中搜索到6 304个SSR位点,分布于5 306条unigene中,出现频率为15.64%。研究结果不仅为挖掘独行菜种子药用次生代谢物生物合成关键基因提供了基础数据信息,而且为独行菜遗传多样性研究和分子标记开发奠定了分子基础。     

Differentiation of Eembryonic sStem cells into cCorneal eEpithelium

Embryonic stem (ES) cell lines were first generated from mouse blastocysts by culturing inner cell mass (ICM) from pre-implantation embryos on feeder lay-ers[1,2]. ES cells have an extensive capacity to preserve their pluripotent nature of self renewing even after genetic manipulation, selection and cryopreservasion in vitro. Many experiments have demonstrated that ES cells have an ability to differentiate into various kinds of cells and tissues naturally originated from all three embryonic…     

变色栓菌产锰过氧化物酶的条件优化

研究了多种培养基组分及培养条件对变色栓菌产锰过氧化物酶(MnP)的影响.当培养基中果糖浓度为20g/L,酒石酸铵浓度为10mmoL/L,吐温80浓度为1.0g/L,MgSO4·7H2O为0.43g/L,最终pH为4.5,500mL三角瓶装液量为100mL,接种量为10片(φ8mm)菌苔,培养温度为30℃,转速为280r/min时,MnP的活力有了很大程度的提高,最高酶活力可达2,270U/L.     

二化螟与作物的相互关系及其影响因素

二化螟Chilosuppressalis(Walker)与作物在漫长的进化史中相互作用和影响,了解二化螟与其寄主的相互作用机制及其影响因素是防治二化螟的重要前提。二化螟在对寄主的选择中有明显的选择行为,而主要寄主之一的水稻由于品种、耕作制度的变更也给二化螟带来了很大的影响;微观技术的介入使得二化螟与作物相互关系的研究进入了新的发展时期。文章从宏观和微观2个角度对二化螟与作物的相互作用及其影响因素进行了探讨,并且对它们的相互作用及其影响因素需深入研究的方向提出了建议。     

ATP-binding cassette (ABC) transporters in normal and pathological lung

ATP-binding cassette (ABC) transporters are a family of transmembrane proteins that can transport a wide variety of substrates across biological membranes in an energy-dependent manner. Many ABC transporters such as P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP) are highly expressed in bronchial epithelium. This review aims to give new insights in the possible functions of ABC molecules in the lung in view of their expression in different cell types. Furthermore, their role in protection against noxious compounds, e.g. air pollutants and cigarette smoke components, will be discussed as well as the (mal)function in normal and pathological lung. Several pulmonary drugs are substrates for ABC transporters and therefore, the delivery of these drugs to the site of action may be highly dependent on the presence and activity of many ABC transporters in several cell types. Three ABC transporters are known to play an important role in lung functioning. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene can cause cystic fibrosis, and mutations in ABCA1 and ABCA3 are responsible for respectively Tangier disease and fatal surfactant deficiency. The role of altered function of ABC transporters in highly prevalent pulmonary diseases such as asthma or chronic obstructive pulmonary disease (COPD) have hardly been investigated so far. We especially focused on polymorphisms, knock-out mice models and in vitro results of pulmonary research. Insight in the function of ABC transporters in the lung may open new ways to facilitate treatment of lung diseases.     

Modeling Sorption of Cd,Hg and Pb in Soils by the NICA-Donnan Model

Metal adsorption is an important process at the soil-solution interface that controls metal bioavailability and toxicity. In this study, batch adsorption experiments were conducted to investigate the binding of Cd, Hg and Pb in soils collected from around metal smelters in Quebec and Ontario, Canada. It was found that soil organic matter enhanced the retention of Cd, Hg and Pb. Assuming that the surfaces of soil particles behaved similarly to organic matter, we used the Non-Ideal Competitive Adsorption (NICA)-Donnan model to derive the parameters for surface complexation of the three metals. The shape of the Cd, Hg and Pb adsorption isotherms are briefly discussed with respect to the results of the experimental measurements and the model predictions. The average values of the NICA-Donnan model parameters could be used to give reasonable predictions of metal sorption in the soils of this study.     

Programmed Cell Death in Relation to Petal Senescence in Ornamental Plants

Cell death is a common event in all types of plant organisms. Understanding the phenomenon of programmed cell death (PCD) is an important area of research for plant scientists because of its role in senescence and the post-harvest quality of ornamentals, fruits, and vegetables. In the present paper, PCD in relation to petal senescence in ornamental plants is reviewed. Morphological, anatomical, physiological,and biochemical changes that are related to PCD in petals, such as water content, sink-source relationships,hormones, genes, and signal transduction pathways, are discussed, Several approaches to improving the quality of post-harvest ornamentals are reviewed and some prospects for future research are given.     

痢疾杆菌酸抗性系统相关基因缺失突变体的构建

依赖于谷氨酸脱羧酶的酸抗性系统对痢疾杆菌在宿主细胞内的生存和繁殖至关重要,hdeA、hdeB、yhiE和yhiF是其中几个重要的酸抗性基因。借助Red系统的重组功能,PCR扩增两翼与目的基因上下游同源的抗性基因片段,电击转化痢疾杆菌2457T,对筛选到的阳性转化子再导入编码FLP位点特异性重组酶的质粒pCP20以去除抗性基因。结果成功的敲除了hdeA、hdeB、yhiE和yhiF等4个酸抗性系统相关基因,为深入研究痢疾杆菌酸抗性基因的调控网络奠定了基础.