Contribution to determination of extracellular DNA origin in the biofilm matrix

This study is focused on the analysis of extracellular DNA (eDNA) from a biofilm matrix formed by Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica. The presence of eDNA in the biofilm of all the studied strains was confirmed by confocal laser scanning microscopy using fluorescent dyes with high affinity to nucleic acid. The protocol for eDNA isolation from the biofilm matrix was established, and subsequent characterization of the eDNA was performed. The purified eDNA obtained from the biofilm matrix of all three microorganisms was compared to the genomic DNA (gDNA) isolated from relevant planktonic grown cells. The process of eDNA isolation consisted of biofilm cultivation, its collection, sonication, membrane filtration, dialysis, lyophilisation, and extraction of DNA separated from the biofilm matrix with cetyltrimethylammonium bromide. An amplified fragment length polymorphism (AFLP) was used for comparing eDNA and gDNA. AFLP profiles showed a significant similarity between eDNA and gDNA at the strain level. The highest similarity, with a profile concordance rate of 94.7% per strain, was observed for S. aureus, L. monocytogenes, and S. enterica exhibited lower profiles similarity (78% and 60%, respectively). The obtained results support the hypothesis that the eDNA of studied bacterial species has its origin in the gDNA.     

日本血吸虫中间宿主湖北钉螺遗传变异的空间相关分析

目的 探讨湖北钉螺的空间遗传结构.方法 采用扩增片段长度多态性（AFLP）分子标记技术对10省或自治区（云南、四川、广西、福建、湖南、湖北、江西、安徽、江苏和浙江）25个钉螺种群基因组DNA进行扩增,分析钉螺种群间的遗传距离与地理距离的相关性.结果 25个钉螺种群间的遗传距离D和Nei无偏遗传距离,都与其地理距离存在明显的正相关性（P＜0.001）,相关系数分别为0.523 4和0.562 2;湖北钉螺指名亚种种群间的遗传距离与地理距离也存在正相关（P＜0.001）,遗传距离D的相关系数为0.527 6,Nei无偏遗传距离的为0.577 0;无论是肋壳钉螺还是光壳钉螺,钉螺种群间的遗传距离都与地理距离存在正相关（P＜0.001）,肋壳钉螺种群间的遗传距离D和Nei无偏遗传距离与地理距离的相关系数分别为0.361 2和0.391 6,光壳钉螺的相关系数分别为0.753 5和0.750 0.结论 在我国大陆广泛分布的湖北钉螺种群间具有明显的空间遗传结构.     

华细辛AFLP反应体系的建立和优化

目的 建立优化的华细辛Asarum sieboldii AFLP反应体系,为华细辛遗传多样性的研究提供技术支持.方法 以华细辛叶片为材料,对基因组DNA提取、酶切连接、PCR扩增等操作过程中各关键因素进行分析,筛选最适条件,建立完善的AFLP反应体系.结果 建立了优化的华细辛AFLP分析体系:在基因组DNA提取时,提取液中添加巯基乙醇、样品温浴时间为30 min;Trul Ⅰ和PstⅠ的酶切时间分别为3 h;在扩增反应中,Mg2+终浓度为1.5 mmol/L、Taq DNA聚合酶用量为0.2 μL.结论 本反应体系可获得良好的AFLP分析结果,可用于华细辛遗传多样性研究.     

Effects of a complex mixture of therapeutic drugs on unicellular algae Pseudokirchneriella subcapitata

Pharmaceutically-active compounds are regularly and widely released into the aquatic environment in an unaltered form or as metabolites. So far, little is known about their potential detrimental effects on algae populations which can ultimately impact nutrient cycling and oxygen balance. For our analysis, the common microalga Pseudokirchneriella subcapitata (P. subcapitata) was exposed to a mixture of 13 drugs found in Italian wastewaters and rivers. Traces of pharmaceuticals investigated were detected in treated algal cells, except for cyclophosphamide and ranitidine, indicating that these algae are able to absorb pharmaceutical pollutants from the environment. The effects of the treatment were investigated by Amplified Fragment Length Polymorphism (AFLP) assessment of DNA damage and 2-DE proteomic analysis. While no genotoxic effect was detected, proteomic analysis showed that algae are sensitive to the presence of drugs and that, in particular, the chloroplast is affected.     

人工肝支持系统成功抢救妊娠急性脂肪肝合并多器官衰竭患者1例报道

目的 分析妊娠急性脂肪肝患者的病例特点、抢救措施及预后,提高对此病的认识及早期诊治水平.方法 回顾性分析1例妊娠急性脂肪肝合并多器官衰竭患者病情演变以及抢救治疗情况,并结合相关文献分析讨论.结果 患者以妊娠晚期出现重度黄疸伴消化道症状起病,常规保肝、退黄等治疗未能逆转病情,并迅速出现肺、肝、肾等多器官衰竭以及DIC等严重并发症,经积极终止妊娠、辅助呼吸及人工肝支持系统等综合抢救最终病情缓解,并经肝组织病理检查明确诊断.结论 妊娠急性脂肪肝病情凶险,极易并发多器官衰竭,早期诊断,多学科、全方位综合救治是提高本病成功抢救的关键.     

Amplified fragment length polymorphism (AFLP) analysis is useful for distinguishing Leishmania species of visceral and cutaneous forms

The Leishmania strains belonging to cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) have been reported to possess close homology in genome profiles. To confirm this on genetic basis an attempt was made to differentiate Leishmania major; Leishmania tropica and Leishmania donovani genetically for the first time using amplified fragment length polymorphism (AFLP)—a high throughput DNA fingerprinting technique. The objective of this research work was to identify DNA markers of CL and VL. Ten combinations of selective primers detect a total of 1487 informative AFLP marker. Percentage of polymorphism was 45.12%. Three hundred and thirty-seven unique AFLP markers were also identified in three species of Leishmania. A clear distinction was revealed between L. major and L. donovani. It was inferred by AFLP analysis that a higher rate of polymorphisms occurred among Leishmania species which indicate the distinguished pattern of the disease cause by Leishmania, i.e. VL and CL. Analysis based on polymorphic AFLP markers revealed considerably high genetic variation among the genome of these species which was sufficient to distinguish between CL and VL.     

Molecular epidemiology of environmental Cryptococcus species isolates based on amplified fragment length polymorphism

Objective

Cryptococcosis is a major opportunistic fungal infection caused by members of the genus Cryptococcus, mainly those belonging to the Cryptococcus neoformans/Cryptococcus gattii species complexes. Here, we report a comprehensive molecular epidemiological study of the environmental distribution of Cryptococcus isolates in Shiraz, Iran with review of litreature.

奈瑟氏淋球菌DNA的AFLP指纹图谱

目的 :评价扩增片段长度技术 (AFLP)分析对淋球菌分离株进行基因分型的能力。方法 :2 6株淋球菌分离株基因以EcoRI和MesI酶切及AFLP分析。结果 :同一地区的淋球菌分离株之间存在相当大的DNA多态性。性伙伴之间分离的淋球菌菌株同源性大于 95 % ,无性关系患者中分离的淋球菌菌株同源性为 70 %～ 95 % ,而不同地点分离株、WHO参考株均不能和本地区分离株聚类。结论 :AFLP是鉴别淋球菌临床分离株有用而敏感的分子技术 ,有助于了解菌株来源、菌株间的克隆相关性及抗生素耐药性的传播