RESUMEN
A novel actinomycete, designated strain A31(T), was isolated from the surface of weathered biotite in Susong, Anhui Province, China. The organism grew optimally at 30 °C, at pH 8.0 and with 1% (w/v) NaCl. Strain A31(T) had A3α as the cell-wall peptidoglycan type and galactose, mannose and rhamnose as whole-cell sugars. Anteiso-C(15â:â0) and anteiso-C(17â:â0) were the major cellular fatty acids and MK-9(H2) was the predominant respiratory quinone. In addition, the total polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylmonomethylethanolamine and four glycolipids. The genomic DNA G+C content of strain A31(T) was 70.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain A31(T) was related most closely to Sinomonas albida LC13(T) (98.3% similarity), Sinomonas atrocyanea DSM 20127(T) (98.2%), Sinomonas soli CW 59(T) (98.1%), Sinomonas flava CW 108(T) (97.8%), 'Sinomonas mesophila' MPKL 26 (97.3%), Sinomonas echigonensis LC10(T) (97.1%) and ' Sinomonas notoginsengisoli ' SYP-B575 (96.7%). DNA-DNA hybridization studies with the new isolate showed relatedness values of 16.0-56.6% with its six closest neighbours. Based on phenotypic, chemotaxonomic and phylogenetic analysis, strain A31(T) represents a novel species of the genus Sinomonas , for which the name Sinomonas susongensis sp. nov. is proposed. The type strain is A31(T) (â=âDSM 28245(T)â=âCCTCC AB 2014068(T)).
Asunto(s)
Silicatos de Aluminio , Compuestos Ferrosos , Micrococcaceae/clasificación , Filogenia , Microbiología del Suelo , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Glucolípidos/química , Micrococcaceae/genética , Micrococcaceae/aislamiento & purificación , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Peptidoglicano/química , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMEN
A natural consortium of two bacterial strains ( Sphingopyxis sp. OB-3 and Comamonas sp. 7D-2) was capable of utilizing bromoxynil octanoate as the sole source of carbon for its growth. Strain OB-3 was able to convert bromoxynil octanoate to bromoxynil but could not use the eight-carbon side chain as its sole carbon source. Strain 7D-2 could not degrade bromoxynil octanoate, although it was able to mineralize bromoxynil. An esterase (BroH) that is involved in the conversion of bromoxynil octanoate into bromoxynil and is essential for the mineralization of bromoxynil octanoate by the consortium was isolated from strain OB-3 and molecularly characterized. BroH encodes 304 amino acids and resembles α/ß-hydrolase fold proteins. Recombinant BroH was overexpressed in Escherichia coli BL21 (DE3) and purified by Ni-NTA affinity chromatography. BroH was able to transform p-nitrophenyl esters (C2-C14) and showed the highest activity toward p-nitrophenyl caproate (C6) on the basis of the catalytic efficiency value (Vmax/Km). Additionally, BroH activity decreased when the aliphatic chain length increased. The optimal temperature and pH for BroH activity was found to be 35 °C and 7.5, respectively. On the basis of a phylogenetic analysis, BroH belongs to subfamily V of bacterial lipolytic enzymes.
