RESUMO
This study reports the identification of ionising radiation tolerant bacteria from a high elevation arid region of central Tibet. Nineteen isolates were isolated from soil exposed to ionising radiation at doses from 0 to 15 kGy. Isolates were phylogenetically characterised using 16S rRNA gene sequences. Most isolates comprised taxa from the Actinobacteria, Cyanobacteria, Firmicutes and proteobacteria and these survived doses up to 5 kGy. The Firmicutes and Deinococci also survived doses up to 10 kGy, and the highest dose of 15 kGy was survived only by the Deinococci. No altitude-related pattern was discernible within the range 4638-5240 m, instead culturable bacterial estimates for irradiated soil were strongly influenced by the abundance of Deinococci. We conclude that the relatively high UV exposure in Tibet has contributed to the high diversity of radiation tolerant soil bacteria. In addition, the strong association between desiccation-tolerance and radiation tolerance pathways suggests the arid environment may also have selected in favour of radiation tolerant taxa.
RESUMO
A culture-independent multidomain survey of biodiversity in microbialite structures within the cold alkaline Pavilion Lake (British Columbia, Canada) revealed a largely homogenous community at depths from 10 to 30 m. Real-time quantitative PCR was used to demonstrate that bacteria comprised approximately 80%-95% of recoverable phylotypes. Archaeal phylotypes accounted for <5% of the community in microbialites exposed to the water column, while structures in sediment contact supported 4- to 5-fold higher archaeal abundance. Eukaryal phylotypes were rare and indicated common aquatic diatoms that were concluded not to be part of the microbialite community. Phylogenetic analysis of rRNA genes from clone libraries (N = 491) revealed that alphaproteobacterial phylotypes were most abundant. Cyanobacterial phylotypes were highly diverse but resolved into 4 dominant genera: Acaryochloris, Leptolyngbya, Microcoleus, and Pseudanabaena. Interestingly, microbialite cyanobacteria generally affiliated phylogenetically with aquatic and coral cyanobacterial groups rather than those from stromatolites. Other commonly encountered bacterial phylotypes were from members of the Acidobacteria, with relatively low abundance of the Betaproteobacteria, Chloroflexi, Nitrospirae, and Planctomycetes. Archaeal diversity (N = 53) was largely accounted for by Euryarchaeota, with most phylotypes affiliated with freshwater methanogenic taxa.
Assuntos
Archaea/classificação , Bactérias/classificação , Biodiversidade , Lagos/microbiologia , Filogenia , Archaea/genética , Bactérias/genética , Sequência de Bases , Colúmbia Britânica , Temperatura Baixa , Cianobactérias/classificação , Cianobactérias/genética , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , Euryarchaeota/classificação , Euryarchaeota/genética , Genes de RNAr , Concentração de Íons de Hidrogênio , Lagos/química , Dados de Sequência Molecular , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Pancreatic mucinous cystic neoplasms (PMCN) predominantly affect women in the reproductive age, are located in the body and tail of the pancreas, and share morphological features with similar tumors of the ovary. We report the detection of human papillomavirus (HPV) using several different PCR protocols in a borderline PMCN from a female patient. Type-specific PCR demonstrated the HPV to be type 16. If confirmed by others, this group of neoplasms might become preventable by HPV vaccination.
RESUMO
Human papillomavirus was successfully detected by polymerase chain reaction (PCR) in menstrual blood or vaginal discharge collected in sanitary napkins in 100% of 17 women having koilocytosis, cervical intraepithelial neoplasia, or squamous carcinoma. We advocate this form of cervical cancer screening because of its high sensitivity and acceptance by patients.
