Isolation And Identification Of Myxobacteria

In this thesis,186 samples collected from Dalian and Wuhan and 30 samples collected from Baiyangdian swamp were isolated and identified, and the species diversity of Myxobacteria in different samples were also studied.Using the rabbit dung, the filter paper and the YWCX to induce the fruiting bodies, Myxobacteria strains were isolated from soil samples collected from Dalian and Wuhan. By compared with the three methods, the result showed that the isolation rates of Myxococcus and Cystobacter were higher than others with the three methods. The best effect one for Myxococcus was rabbit dung inducing method, and the filter paper inducing method was fit for Cystobacter. The isolation methods of samples collected from Baiyangdian swamp were complicated. Wet soil samples were treated using the inducing method, soil samples using the inducing method and dilution method, water samples using the filtrate method and the rabbit dung inducing method, and float grass samples using the filter paper inducing method. We obtained 234 Myxobacteria strains from 216 samples.These 234 Myxobacteria strains were primarily identified to genus level by their morphology, and they belonged to 8 generas:Myxococcus, Cystobacter, Archangium, Nannocystis, Haploangium, Angiococcus, Stigmatella and Corallococcus. The study of physiological and biochemical characteristics of 23 tested strains helped to the identification of these strains. According to 16S rDNA sequences and phylogeny analysis,6 tested strains belonged to Myxococcus. It came to the same results with morphorlogical identified conclusion.Analysing biodiversity of Myxobacteria strains in 216 samples, the result showed that myxobacteria in samples from Dalian have a better diversity than those from Baiyangdian swamp. Myxobacteria in samples with plants have a more advantage in quantity and diversity than those in samples without plants. Myxobacteria have a large quantity and a good diversity in nutritious soil samples. For samples from Baiyangdian swamp, Myxobacteria in soil samples have a better quantity and diversity than those in water samples.