Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in ...Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water(DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phy-logenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4 strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.展开更多
Hypersaline environments are colonized by communities of microorganisms, which developed adaptations from halotolerant to extreme halophilic lifestyles. Twenty-four halophilic archaeal strains were isolated from three...Hypersaline environments are colonized by communities of microorganisms, which developed adaptations from halotolerant to extreme halophilic lifestyles. Twenty-four halophilic archaeal strains were isolated from three Algerian hypersaline sites, including the solar salterns in Ichekaben and two natural salt lakes at Ouargla and Oran. Almost full-length 16S rRNA genes were amplified using archaeal-specific primers, sequenced and phylogenetically analyzed. Three isolates from the salt lake of Ouargla were affiliated to Halorubrum sp., while six isolates from Ichekaben were Natrinema sp.. The remaining strains belonged to the genus Haloarcula, which was identified in the three Algerian sites. A phylogenetic tree of Haloarcula sp. including the two copies of the 16S rRNA gene, showed that two strains group with Haloarcula hispanica, while the other 13 cluster with OHF-1/OHF-2 isolated from French commercial salt. Both Natrinema sp. and Haloarcula sp. were persistent at Ichekaben. For the six Natrinema sp. isolates, this observation correlates with their capacity to produce antimicrobial compounds, and a DNA fragment closely related to the halocin C8 gene was amplified for five strains.展开更多
文摘Among the 116 actinomycetes collected from marine sediments of the Yellow Sea,56 grew slowly and appeared after 2?3 weeks of incubation.Among the 56 strains,only 3 required seawater(SW) for growth,and 21 grew well in the medium prepared with SW rather than distilled water(DW),while the remaining 32 grew well either with SW or with DW.Six representatives with different morphological characteristics,including 1 SW-requiring strain and 5 well-growing with SW strains,were selected for phy-logenetic analysis based on 16S rRNA gene.Two strains belong to Micrococcaceae and Nocardiopsaceae respectively.The other 4 strains belong to the family of Streptomycetaceae.In the analyzed 6 strains,one was related to Nocardiopsis spp.and the other three were related to Streptomyces spp.,representing new taxa.Bioactivity testing of fermentation products from 3 SW-requiring strains and 21 well-growing with SW strains revealed that 17 strains possessed remarkable activities against gram-positive pathogen or/and tumor cells,suggesting that they were prolific resources for natural drug discovery.
文摘Hypersaline environments are colonized by communities of microorganisms, which developed adaptations from halotolerant to extreme halophilic lifestyles. Twenty-four halophilic archaeal strains were isolated from three Algerian hypersaline sites, including the solar salterns in Ichekaben and two natural salt lakes at Ouargla and Oran. Almost full-length 16S rRNA genes were amplified using archaeal-specific primers, sequenced and phylogenetically analyzed. Three isolates from the salt lake of Ouargla were affiliated to Halorubrum sp., while six isolates from Ichekaben were Natrinema sp.. The remaining strains belonged to the genus Haloarcula, which was identified in the three Algerian sites. A phylogenetic tree of Haloarcula sp. including the two copies of the 16S rRNA gene, showed that two strains group with Haloarcula hispanica, while the other 13 cluster with OHF-1/OHF-2 isolated from French commercial salt. Both Natrinema sp. and Haloarcula sp. were persistent at Ichekaben. For the six Natrinema sp. isolates, this observation correlates with their capacity to produce antimicrobial compounds, and a DNA fragment closely related to the halocin C8 gene was amplified for five strains.
