A fluorescent amplified fragment length polymorphism study of Salmonella enterica serovar Sofia, the major Salmonella serovar isolated from chickens in Australia

Fluorescent amplified fragment length polymorphism (FAFLP) analysis was performed on 68 isolates of Salmonella enterica subsp. salamae serovar Sofia (S. Sofia). Fifty eight isolates were obtained over a period of approximately 15 years from a range of human, chicken industry and environmental sources throughout Australia. A further ten isolates were identified from human and poultry sources in Israel from 1972 to 1987. Analysis of FAFLP profiles for fragments between 50 to 500 base pairs in length indicated distinct clusters of isolates. All but seven isolates clustered into four groups of >90% similarity and all isolates displayed at least 70% similarity with each other. No cluster could be attributed to a particular geographical, temporal or source-of-isolation origin. It is concluded that S. Sofia is genetically variable with certain clones persisting over time but no group appears unique to Australia.     

The giant B chromosome of the cyprinid fish Alburnus alburnus harbours a retrotransposon-derived repetitive DNA sequence

The cyprinid fish Alburnus alburnus possesses one of the largest supernumerary chromosomes in all vertebrates. In the present study, amplified fragment length polymorphism analyses (AFLP) and fluorescence in-situ hybridization (FISH) were performed in order to characterize these extraordinary chromosomes in detail. Sequence analysis of the B chromosome-specific DNA revealed a strong homology to a Drosophila Gypsy/Ty3 retrotransposon and also to a medaka (Oryzias latipes) one. The sequence is highly abundant on the B chromosome but undetectable in the normal A chromosome complement. It is also absent from the B chromosome of the closely related species, Rutilus rutilus, suggesting a specific spreading of the mobile element during evolution of the giant supernumerary chromosome within A. alburnus. Meitotic chromosomes were in-situ hybridized with the B chromosome-specific probe, documenting that the additional chromosome behaves as an autopaired ring chromosome in diakineses. Our results suggest that the supernumerary chromosome of A. alburnus is not derived from the normal chromosome complement but has evolved independently.     

Genotypic diversity and antibiotic susceptibility of Acinetobacter baumannii isolates in a Bulgarian hospital

A set of 18 Acinetobacter baumannii isolates, collected prospectively in a Bulgarian hospital during episodes of increased A. baumannii occurrence during 2000-2002, was investigated for genotypic diversity and antibiotic susceptibility. Four genotypes were identified by amplified fragment length polymorphism genomic fingerprinting, one of which (type 1) accounted for 13 isolates, indicating that a specific strain was predominant. The single isolate allocated to type 2 was identified to European clone I. All isolates were resistant to multiple antibiotics, but most retained susceptibility to tobramycin and colistin, and all except one were susceptible to imipenem.     

Nosocomial Legionella pneumophila serogroup 5 outbreak associated with persistent colonization of a hospital water system

An outbreak of infections caused by Legionella pneumophila serogroup 5 was detected in a university hospital, and nosocomial reservoirs of the legionella epidemic were examined. Clinical isolates from two patients who had been affected by the L. pneumophila serogroup 5 outbreak, and from another patient with a legionella infection caused by the same serogroup 3 years later, were compared to L. pneumophila serogroup 5 isolates from the hospital water supply by two molecular methods, amplified fragment length polymorphism (AFLP) analysis and random amplified polymorphic DNA analysis (RAPD). Genotyping confirmed the epidemiological linkage of the first two patients, and linked their infections with the hospital water supply. The third clinical strain, which was also linked to the hospital water, was very similar to the epidemic strain. Even though the water distribution system was sanitized (superheat and flush sanitation), the epidemic strain was shown to be persisting in the hospital water outlets several years after its initial discovery.     

AFLP分析唐古特大黄、掌叶大黄和药用大黄的亲缘关系研究

目的研究《中国药典》2005年版收载蓼科大黄属3种大黄(唐古特大黄、掌叶大黄和药用大黄)的亲缘关系。方法对3种大黄44份样品进行AFLP分析,同时利用NTSYSpc-2.11F软件分析其亲缘关系。结果8对选择性扩增引物中,扩增得到1 255条稳定清晰的条带,其中多态性条带1 209条,多态性带占总带数的96.2%。将44份大黄样品分为2组2个亚组。四川若尔盖唐古特大黄聚为第一组,第二组分为两个亚组,分别为药用大黄和掌叶大黄。另外,大黄的AFLP分子标记谱带显示,3种大黄和不同来源的大黄样品间除了具有共有带外,还有一些特异带,说明种间甚至不同来源的样品间有一定程度的特异性。结论《中国药典》规定的3种正品大黄中,药用大黄和掌叶大黄亲缘关系较唐古特大黄近,表明利用AFLP技术分析3种大黄的亲缘关系可行。     

短柄乌头遗传多样性的AFLP分析

目的对濒危药用植物短柄乌头Aconitum brachypodum遗传多样性进行研究。方法选用3对引物对短柄乌头4个自然居群105个样品进行了AFLP分析,利用POPGENE32、MEGA4、NTSYS等生物统计软件进行相关参数计算和聚类分析。结果在短柄乌头物种居群间的遗传多样性水平上,多态位点百分率为80.57%,Nei’s基因多样性指数(He)为0.322 9±0.179 8,Shannon’s信息指数(I)为0.472 0±0.251 7。在其居群内,多态位点百分率为12%,He为0.115 4±0.044,I为0.168 0±0.065 3。Nei’s基因分化系数(Gst)为0.864 2。聚类分析表明,禄劝居群和东川居群聚为一支,丽江居群和会泽居群聚为一支。结论短柄乌头物种居群间的遗传多样性丰富,居群内的多样性偏低。居群间存在显著的遗传分化。AFLP对短柄乌头的遗传多样性分析对其保护提供依据。     

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.     

Prevalence and diversity of filamentous fungi in the airways of cystic fibrosis patients – A Dutch,multicentre study

Background

Progressive lung injury in Cystic Fibrosis (CF) patients can lead to chronic colonization with bacteria and fungi. Fungal colonization is obtained from the environment which necessitates locally performed epidemiology studies. We prospectively analyzed respiratory samples of CF patients during a 3-year period, using a uniform fungal culture protocol, focusing on filamentous fungi and azole resistance in Aspergillus fumigatus.