Taxonomic Identification Of Actinoplanes Lutulentus And Micromonospora Jinlongensis And Preliminary Activity Study Of Isolated Strains

Actinomycetes are a very important microbial source to produce natural active compounds. In the past, most (about70%) of antibiotics were isolated from Streptomyces, so it is more difficult to find new active substances from Streptomyces which are easier to be separated. Actinomycetes of different taxa often have different metabolic pathways. Rare actinomycetes become a good source to produce new antibiotics, In the research, we isolated actinomycetes from four soil samples with seleetive isolation methods to rare actinomycete, then did the research including new species identification and activity study of fermentation products. The results were as follows:(1) A total of85actinomycetes were isolated from four soil samples collected from different regions of our country, and grown on various agar media including mainly HV, Gauze’s medium no.1and modified Gause II medium, supplemented with inhibitor combination including cycloheximide (50mg1-1) and nalidixic acid (20mg1-1) and with potassium dichromate (50mg1-1). Actinomycetes were isolated twice from every soil sample.(2) The plate method and cross method were used respectively to determine antibacterial activity of extract of fermentation broth of85actinomycetes strains, including two kinds of bacteria and ten kinds of pathogenic fungi of our laboratory. The results showed that11strains were equally most effective against Bacillus subtilis and Micrococcus luteus, and the inhibition zone diameters were above15mm, of which6strains proved to have the highest antagonistic activity and the inhibition zone diameters were above20mm. The experiment showed that19strains had significant inhibitory effect on at least two kinds of the pathogenic fungi and5of them had a significant inhibitory effect on at least five kinds of the pathogenic fungi, of which the strain GHH20and GSL8were effective against the ten pathogenic fungi. These research were the foundation for the subsequent separation of active compounds.(3) The strains GRX6and GRX11were characterized using a polyphasic approach, including morphological characteristic, physiological and biochemical characteristics, analysis of chemotaxonomy,16S rRNA sequenees, G+C contents and DNA-DNA homologies ete. Their taxonomic status were finally determined based on their phenotypic, genetic and phylogenetic characteristics. Strains GRX6was identified as a novel species of the genus Actinoplanes, for which the name Actinoplanes lutulentus sp. nov. was proposed. The type strain of Actinoplanes lutulentus is strain NEAU-GRX6T (=CGMCC4.7090T=DSM45883T). The GenBank accession number for the16S rRNA gene sequence of strain NEAU-GRX6T is KC134255. The paper was published in IJSEM2014,64:1782-1788. Strain GRX11was a novel species of the genus of Micromonospora, for which the name Micromonospora jinlongensis sp. nov. was proposed. The type strain is NEAU-GRX11T (=CGMCC4.7103T=DSM45876T). The GenBank accession numbers for the16S rRNA gene and gyrB gene of strain NEAU-GRX11T are KC134254and KF318646, respectively. The article was published in Anton Leeuw Int J G2014105307-315.