title: Oligotrophy is Helpful for the Isolation of Bioactive Actinomycetes.
abstract: It is necessary to develop new methods for the isolation of unknown actinomycetes from soils. To evaluate the effects of oligotrophic medium on the isolation of soil actinomycetes and develop a new isolation method, the Gause's synthetic medium was diluted to one tenth the recommended concentration in the present study. Soil dilution plate technique was used to isolate actinomycetes from the soil samples. Oligotrophy decreased actinomycete and streptomycete counts, as well as the number of antagonistic actinomycete species. Oligotrophy also decreased the number of actinomycete species in five samples. Some actinomycete species were cultured only on the oligotrophic medium, whereas other species could not be cultured. Oligotrophy decreased actinomycete counts more significantly for soils with organic matter content >40 g/kg. We used 16S rRNA sequence analysis to identify 22 actinomycete species that were only cultured on the oligotrophic medium. Oligotrophic medium was helpful for the isolation of Streptomyces spp., Micromonospora spp. and Streptosporangium spp. Slightly more than 80 % of the identified actinomycete species were biologically active. Therefore, we could draw a conclusion that oligotrophic medium could be helpful for the discovery of new antibiotic producers and the exploitation and utilization of new, biologically active compounds.
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi China.
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Wang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi China.
authors.forename: Quan-Hong
authors.initials: QH
authors.lastname: Xue
authors.affiliation: College of Life Science, Northwest A&F University, Yangling, Shaanxi China.
authors.forename: Yun-Yan
authors.initials: YY
authors.lastname: Ma
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wei
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Life Science, Northwest A&F University, Yangling, Shaanxi China.
authors.forename: Fei
authors.initials: F
authors.lastname: He
keywords: 16S rRNA; Antagonistic actinomycetes; Gause’s synthetic medium; Taibai mountain