| In the first chapter of this thesis, isolation methods of actinomycetes have been introduced and the current methods applied to polyphasic taxonomy for actinomycetes have been presented.In the second chapter of this research . Three strains of streptomyces-phages (HPA1, HPA2, HPA3) were isolated from soil samples collected from Baoding . China. To study them can be used them to isolate actinomycetes by knowing their characteristics.Their morphology and stability were studied. The morphologies of their plaques are different in nutrient agar medium. The plaque's size of HPA1 is medium and transparent. The plaque of HPA2 has transparent center with obscure edge .which is bigger than others and similar as solar halo. The last type of PHA3 is small and like pin prick. The result of electronic microscope showed that external forms of their heads are all circular shape, but the sizes and length of their tails are varied. HPA1 has long tail .and HPA3 has short tail, while HPA2 has no tail . Their host range is narrow. They are unable to infect Streptosporangium strains and other actinomycetes, expect some streptomyces species. Among the three streptomyces-phages (HPA1. HPA2. HPA3) . HPA2 is more tolerate to temperature than others. When temperature reached 60?. 21?. of HPA2 were still survived. HPA1 and HPA3 are sensitive to chloroform, while HPA2 is resistant to chloroform. In addition, they are all sensitive to ultraviolet ray. When they were expose to ultraviolet ray for 5 minutes, their rates of Plaque-forming were outstandingly decreased. They all have obvious resistance to potassium dichromate and actidione.In the third chapter of this thesis, three strains of streptomyces-phages (HPA1. HPA2. HPA3) were used to selective isolate actinomyces from 6 soil samples collected from different regions of Yunnan. The result of study showed the number of Actinomyces in the isolating plates added into streptomyces-phages (HPA1. HPA2. HPA3) was lager than those non-added into them. The test indicates that it is possibleAbstractto isolate new typies of actinomyces by using streptomyces-phage and some common Streptomyces were inhabited by using this method. It is useful for the study of microbe resource and mocrobe diversity .The last chart of this research, polyphasic taxonomy methods were used for systematics of five strains of actinomycetes isolated with the methods above.By morphological studies, strain Y70011, Y70012 were spesical, which had leather-like colnes had some unconspicuous difference.They could produce many crystal.Strain Y70013 beared column spores which had smooth surface. Strain Y70014 could beared oval spores which had thorn surface. Strain Y700I5 could beared sporangia.The result of chemotaxonomy showed: strain Y70011, Y700I2, Y70013 and Y70014 contain LL-DAP in their cell wall. The type of major phospholipids are P II. their main menaquinones were MK-9(H4.). MK-9(H6) and MK-9(H8). Strain Y70015 contains meso-diaminopimelic acid in its cell wall. The type of major phospholipids are PIV. their main menaquinones were MK-9(H2.)- MK.-9(H1).DNA G+Cmol% and 16S rDNA sequence analysis were determined. DNA G+C% of strains matched to their genera. The phylogenetic relationship of five strains were revealed by phylogenetic analysis. It can be determined that Y70011. Y70012. Y70013 and Y70014 belong to Streptomycetes and Y70015 belong to Sterptospomngium. The sequence homology of strain Y70011 with the most similar type strain Streptomycetes cyaneus was 97.762%. The sequence homology of strain Y70012 with the most similar type strain Streptomycetes cyanem was 97.629%.Strain Y70011 and strain Y70012 most like new species of Streptomycete. but the sequence homology between them was 99.929%. Whether they were same specie . DNA-DNA homology analysis would be still used. The sequence homology of strain Y70014 with the most similar type strain Streptomycetes avermitilis was 97.323%. It most like a new specie of Streptomvceles. The sequence homology of strain...
|
PDF Full Text Request