Jiang, Yi (2009) Systematic Research on Actinomycetes Selected According to Biological Activities. (PhD/ Doctoral thesis), Christian-Albrechts-Universität Kiel, Kiel, Germany, 142 pp.

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Abstract

Summary Actinomycetes (Actinobacteria) are the group of bacteria producing most of the bioactive metabolites. Approx. 100 out of 150 antibiotics used in human therapy and agriculture are produced by actinomycetes. Finding novel leader compounds from actinomycetes is still one of the promising approaches to develop new pharmaceuticals. The aim of this study was to find new species and genera of actinomycetes as the basis for the discovery of new leader compounds for pharmaceuticals. Unique and extreme habitats as a source for Actinomycetes combined with variation in sample treatment and isolation media have been shown to yield a great diversity of Actinomycetes including a number of new species and genera. 990 soil and sediment samples were collected from primeval tropical rain forest, secondary forests, mangroves, saline and alkaline soil and lakes in five Provinces, P. R. China and Baltic Sea. 4127 strains of actinomycetes were isolated by using various pretreatment procedures and different media. In total, 230 strains were selected for taxonomic research, among these 26 strains with anti-cancer activities, 22 with PKS genes, 32 with enzymes inhibition, 14 from salt and alkaline environments, 136 rare actinomycetes. On the basis of partial sequences of the 16S rRNA gene, these 230 strains were identified at the genus level and found to belong to 40 genera. A selection of 62 strains was further characterized by almost complete sequences and by polyphasic taxonomic procedures. Eight new species were published previously. Two new genera, Actinomycetospora chaingmaiensis sp.nov. and gen. nov. and Planosporangium flavogriseum sp. nov. and gen. nov. and two new species, Streptomyces hainanensis sp. nov. and Promicromonospora flava sp. nov., were described in this thesis. In order to find un-known actinomycetes for providing the new sources for discovery of new leader compounds. First, test samples should be collected from primeval and special or extreme habitats; second, Actinomycetes should be isolated by using new, specific and variable procedures; third, Isolates are characterized by using fast identifying methods, especially a part of sequencing of 16S rRNA genes.

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