RESUMO
So far, little is known about the diversity of the radiation-resistant microbes of the hyperarid Taklimakan Desert. In this study, ionizing radiation (IR)-resistant bacteria from two sites in Xinjiang were investigated. After exposing the arid (water content of 0.8 ± 0.3%) and non-arid (water content of 21.3 ± 0.9%) sediment samples to IR of 3000 Gy using a (60)Co source, a total of 52 γ-radiation-resistant bacteria were isolated from the desert sample. The 16S rRNA genes of all isolates were sequenced. The phylogenetic tree places these isolates into five groups: Cytophaga-Flavobacterium-Bacteroides, Proteobacteria, Deinococcus-Thermus, Firmicutes, and Actinobacteria. Interestingly, this is the first report of radiation-resistant bacteria belonging to the genera Knoellia, Lysobacter, Nocardioides, Paracoccus, Pontibacter, Rufibacter and Microvirga. The 16s rRNA genes of four isolates showed low sequence similarities to those of the published species. Phenotypic analysis showed that all bacteria in this study are able to produce catalase, suggesting that these bacteria possess reactive oxygen species (ROS)-scavenging enzymes. These radiation-resistant bacteria also displayed diverse metabolic properties. Moreover, their radiation resistances were found to differ. The diversity of the radiation-resistant bacteria in the desert provides further ecological support for the hypothesis that the ionizing-radiation resistance phenotype is a consequence of the evolution of ROS-scavenging systems that protect cells against oxidative damage caused by desiccation.
Assuntos
Bactérias/classificação , Bactérias/efeitos da radiação , Clima Desértico , Raios gama , Tolerância a Radiação , Microbiologia do Solo , Actinobacteria/classificação , Actinobacteria/genética , Bactérias/genética , Bactérias/isolamento & purificação , Catalase/metabolismo , China , Variação Genética , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/isolamento & purificação , Bactérias Gram-Positivas/efeitos da radiação , Fenótipo , Filogenia , Proteobactérias/classificação , Proteobactérias/genética , RNA Ribossômico 16S/genética , Espécies Reativas de Oxigênio/metabolismoRESUMO
OBJECTIVE: To investigate the application of Koyanagi technique for repairing proximal hypospadias with penoscrotal transposition. METHODS: Koyanagi procedure was used for repairing proximal hypospadias with penoscrotal transposition in 26 boys (mean age 4.2 years) between July 2005 and June 2010. RESULTS: Primary healing was achieved in 22 cases. Three patients suffered from urinary fistula and the external urethral orifice in one patient was retracted to penis coronary sulcus, who were re-operated successfully. Two cases showed slight penile ventral curvature. Slight stricture of the urethral external orifice was noted in one case, which relieved after one to two times of urethral sounding every week for eight months. 20 patients were followed up for 6-36 months (mean 10.5 months) with good cosmetic result and normal urethra function. The penoscrotal transposition was also corrected. CONCLUSIONS: The original Koyanagi procedure might be one of the simple and effective method for repairing proximal hypospadias with penoscrotal transposition.