| Summary: | 碩士 === 東吳大學 === 微生物學系 === 95 === Purple non-sulfur bacteria are a group of extraordinary metabolic
diverse bacteria. They can grow with photoautotroph, photoheterotroph, chemoheterotroph or chemoautotroph. Under various conditions, they can enjoy exceptional flexibility within each of these modes of metabolism. Due to the special physical characteristics properties, they had attracted scientist’s attention in resent years. These bacterias are widely distributed in nature such as lakes, water ponds, seas, or farm, etc. We isolated 39 strains bacteria from different aqueous phase of northern Taiwan. We discussed the diversity of their morphology and genetic diversity of their 16S-23S ribosomal intergenic spacer region(ISR) . First, dependent on cell shapes, we classed these strains into seven types: coccus, oval, ring, horse's hoof, and three size rods. Colors of their cell suspension are brown, pink, purple and red-brown, etc. Their cultural characteristics almost are circular forms , convex elevation and entire margins. Then, according to above characteristics, we classed 39 strains in to twenty-six clusters. Taking 16S rRNA sequence of these 26 representatives to blast with DataBank , the similarity all are larger than 99%，which reveals they were related to Rhodobacter sphaeroides, Rhodovulum sulfidophilum and Rhodopseudomonas sp. and revealed there were highly diversity of their morphology . In other hand, the16S-23S ISR of 39 strains were amplified by PCR and digested with PvuII, AluI, HaeIII, resulting in 22 RFLP profiles. This results showed that 39 purple nonsulfur bacterias could be classed into 22 groups. 16S-23S ISR-RFLP revealed that there was a genotype diversity within Rba. sphaeroides and Rhodovulum sp. strain MB263,which there were different 7 and 2 RFLP profiles respectively. This result showed that there was genotype diversity of 16S-23S ISR with both species ,or may that there was not enough database of 16S rRNA sequence in GenBank to blast accurately to the species. Hence, analysis of 16S-23S ISR-RFLP was more accurate than analysis of 16S rRNA sequences for identification of purple non-sulfur bacteria. By this method, 16S-23S ISR-RFLP, we can set up a characterization system of purple non-sulfur bacteria.
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