金花茶遗传多样性的ISSR分析

采用ISSR分子标记对金花茶的4个自然分布居群的126份样品的遗传多样性水平进行了研究。用12条引物,共检测到105个清晰的扩增位点,其中多态性位点79个,多态位点百分率(PPB)为75．24％。采用POPGENE软件进行分析,结果表明：居群总的Nei’s基因多样性指数为0．2302,Shannon信息多态性指数为0．3502,金花茶总的遗传多样性水平较高。但金花茶居群内的遗传多样性相对较低。基因分化系数为0．5752,遗传变异主要存在于居群间。用NTSYS软件对样品进行UPGMA聚类分析,结果4个居群的样品各自聚在一起,而金花茶两间断分布区区内的居群又各自聚在一起。金花茶4个居群间的遗传距离与地理距离呈显著的正相关(r=0．68261,P=1．0000)。     

Genomic compositions and phylogenetic analysis of Shigella boydii subgroup

The living conditions of bacteria are various and complex. Even for those closely related strains, there are significant differences in their biological charac-teristics and genomic compositions. Therefore, the information obtained from single strain geno…     

Closing the carbon budget of estuarine wetlands with tower-based measurements and MODIS time series

Compared to other ecosystems, estuarine ecosystems have distinct carbon flux dynamics – the lateral carbon flux incurred by tidal activities, and methane generation under the anaerobic conditions of wetland soils. The conventional estimation of gross primary production (GPP) based on the light use efficiency (LUE) model used for non‐wetland terrestrial ecosystems, therefore, cannot be applied directly to estuarine wetland ecosystems. In this paper, we estimated the 2005's annual carbon budget of an estuarine wetland on Chongming Island, Shanghai, and partitioned the losses of carbon due to lateral tidal dynamics and anaerobic methane production using an innovative technique. The average GPP calculated from eddy covariance between March and November was 261.79 μmol m^?2 day^?1, whereas that from the LUE model was 58.84 μmol m^?2 day^?1. The correlation coefficient between GPP simulated from the LUE model and that calculated from flux tower data was low in the growing season (R²=0.55). We hypothesized that tidal activities and uncounted methane release were responsible for the difference, which can be predicted from measurements of remote sensing products such as land surface water index (LSWI), evapotranspiration (ET), and tide height (TH). We developed an integrated GPP model by combining the LUE model and an autoregression model to estimate carbon budget. The average GPP from the modified model increased to 263.38 μmol m^?2 day^?1, and R² for the correlation between the simulated and calculated data increased to 0.88, demonstrating the potential of our technique for GPP estimation and quantification of seasonal variation in estuarine ecosystems. The approach developed in this study has great potential for correcting unavoidable errors when estimating carbon budget of coastal wetlands. Furthermore, global warming is expected to accelerate sea level rise, which may enhance the effect of tidal activities and increase the difficulty in estimating coastal carbon budgets using conventional methods.     

蝮蛇咬伤患者肌酸激酶和肌钙蛋白I的变化与心功能相关性研究

目的 探讨蝮蛇咬伤患者心肌酶学(CK-MB、CK)和肌钙蛋白I(cTnI)变化与心功能的相关性.方法 将106例蝮蛇咬伤患者按病情程度分为轻、重、危重型3组,对3组患者的心肌肌钙蛋白I及心肌酶学、左室Tei指数进行测定并进行比较分析.结果 危重型组患者的CK、CK-MB、Tei指数、cTnI阳性率均高于轻、重型组,差异有显著性(P<0.05).cTnI呈阳性患者的左室Tei指数与CK、CK-MB相关系数为0.311、0.266.结论 cTnI对蝮蛇咬伤患者心肌损伤的敏感性及特异性均高于CK和CK-MB.蝮蛇咬伤中毒患者心肌酶学升高可以判断骨髂肌损伤程度,只有极少数危型蝮蛇咬伤患者合并有心肌损伤,左室Tei指数测定也证实蝮蛇咬伤cTnI呈阳性者均有心功能受损.     

Phylogeny and biogeography of Alyssum (Brassicaceae) based on nuclear ribosomal ITS DNA sequences

The genus Alyssum consists of about 195 species native to Europe, Asia and northern Africa. All species were assigned to six sections. Previous molecular phylogeny studies indicate that Alyssum is polyphyletic. However, the divergence time and dispersal of the genus are not well studied. In this study, the phylogenetic relationships within the genus Alyssum were studied with nrDNA ITS sequences obtained from five sections. The divergence time was estimated by fossil calibration and the biogeography was examined by spread analysis. The phylogeny indicated two main lineages: lineage 1 includes the section of Alyssum, Gamosepalum and Psilonema; lineage 2 includes the section of Odontarrhena, Meniocus and Clypeola. The phylogenetic relationship was not congruent with the previous sectional classifications. The age of Alyssum was dated to the upper Miocene. Molecular data suggested the diversification of Alyssum in Mediterranean areas and wide-ranging distribution such as North Africa, eastward into Central Asia and immigration into North America. Climatic aridification and arid/semiarid areas established in the Pliocene/Pleistocene could have provided favourable conditions for the migration and diversification of Alyssum.     

硫化氢在急性百草枯中毒致大鼠肺损伤中的作用

目的阐明百草枯中毒致大鼠肺损伤时机体内源性H2S的变化,探讨硫化氢在急性百草枯中毒致大鼠肺损伤中的作用。方法按时间点将50只大鼠分为5组,同时染毒;选择对应时间点50只大鼠为对照组。分组检测肺组织中内源性H2S的含量,并及时处死大鼠,行肺组织损伤病理学评分。另外取大鼠40只分为4组,即空白对照组、染毒组、染毒+外源性H2S组、外源性H2S组,于12h后,检测肺组织中内源性H2S的含量,并及时处死大鼠,行肺组织损伤病理学评分。结果百草枯中毒致大鼠肺损伤在不同时间范围内,机体内源性H2S的含量差异有显著统计学意义(P0.01);与染毒组比较,染毒组+外源性H2S组肺损伤程度评分显著降低,差异具有显著统计学意义(P0.01)。结论百草枯致大鼠肺损伤过程中,内源性H2S的含量与肺损伤程度呈负相关;外源性H2S通过增加体内肺组织H2S的含量,抑制百草枯致肺损伤。。     

嗜极性木聚糖酶

木聚糖酶内切水解木聚糖主链的1,4-β-D-糖苷键,木聚糖是植物细胞壁中一种主要的多糖。自然界中木聚糖是多种糖类的复合体,这就使得木聚糖酶呈现多态性和多域性,由此需将繁多的木聚糖酶进行归类。木聚糖酶的催化反应属于双置换机制。在已研究的真菌或细菌性木聚糖酶中,大多数在温和的条件下表现出最佳活性,但有很多在极端环境下生长的生物体,为了适应极端环境而产生嗜极性的酶,其中嗜酸的、嗜碱的、嗜热的木聚糖酶,现在已有广泛的研究。对嗜极性木聚糖酶的研究进展作了论述。