Dissertation > Medicine, health > Pharmacy > Drug basic science

Polyphasic taxonomic study of bacteria virginiamycin new class of antibiotic X-435-C X-435 and co-cultured microorganisms in screening the application of physiologically active substances

Author ZhaoHongJuan
Tutor ZhangYueQin
School Peking Union Medical College , China
Course Microbial and Biochemical Pharmacy
Keywords virginiamycin-producing organism Ribotyping 16S rRNA DNA-DNA hybridization Streptomyces beijingensis sp. nov. dominant strains coculture Type III soil extract-requiring strains micro colony
Type PhD thesis
Year 2000
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In this study the polyphasic taxonomy of new virginiamycin-like compound X-435-C producing-organism X-435 using phenotypic, genotypic and phylogenetic information will be discussed.The strain X-435 is a gram-positive, aerobic, non-fast-acid, virginiamycin-producing organism isolated from the soil sample in Beijing. It belongs to the genus Streptomyces according to the information on cellular chemical composition( cell wall type I, phospholipids type II, MK-9(H4,6,8) and G+C content(71%), morphology of mycelia and spore chains. Nonfragmenting and branching hyphae are present. Aerial mycelia are abundant on most media. X-435 has moderate spore-chains in length. Compared with all of the reported virginiamycin-producing organisms, X-435 is similar to IFO13455(S.graminofaciens), IFO13074(S.pristinaespiralis). They are all included in grey series. Study on the charateristics of morphology indicates that X-435, IFO13455 and IFO13074 all produce warty spores and their spore-chains is irregular spiral; but the type of their spirals and spores is different. The spores of X-435 are cylinder, the other two are elliptic cylinder or spheric. As for the cultural properties, there is some great difference in pigment production, color of substrate and aerial mycelia.There is no great difference in their physiological and biochemical characteristics except that strain X-435 can hydrolyse cellulose and does not use raffinose as the sole carbon and energy source while IFO13074, IFO13455 can’ t hydrolyse cellulose and can use raffinose.Ribotyping is used in this study to analyse the rRNA restriction pattern of strains X-435 and IFO13455, IFO13074 using DIG-labeled rRNA probe. X-435 is different from the other two according to the band pattern of hybridization. So it is proposed that X-435 is different from all of the other reported virginiamycin-producing microorganisms.To define the taxonomic position of X-435, 16S rRNA sequencing is analysed. After sequence comparison of 16S rRNA with all of the accessed streptomyces in GenBank and RDP, 30 strains which show more than 96% 16S rRNA/rDNA sequence similarity versus X-435 are selected to establish phylogenetic dendrogram. According to this dendrogram, strains IFO12836(S.ambofaciens) and IFO12749(S.caelestis) are proposed to be the

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