Studies On The Molecular Classification And Preservation Of Myxobacteria

In this research some myxobacteria strains which had been conserved were chosen to be studied by the analysis on completed sequences of 16S rDNA, so that the Phylogenetic taxonomy analysis studies were carried out on them, and then they were studied by the analysis on DNA G+C mol% and DNA-DNA hybridization.Througth studying the completed sequences of 16S rDNA of 30 myxobacteria strains, the results indicated that the 30 strains belonging to Bacteria, Proteobacteria, Delta-proteobacteria, Myxococcales, Cystobacterineae. Strain 92054 belongs to genus Corallococcus, strain 91081 belongs to genus Melittangium and the other 28 strains belong to genus Myxococcus.Strain 92054 is similar to Corallococcus coralloides DSM 2259T and their sequence similarity is 99.79%.Strain 91081 is similar to Melittangium lichenicola DSM 2275T and their sequence similarity is 99.80%.Based on the sequence of 16S rDNA, the 28strains of Myxococcus were distributed into 3 groups.22 strains such as strain WH114s-1 are similar to Myxococcus fulvus ATCC 25199T and the sequence similarity of the 5 strains of all the 22 strains such as strain WH114s-1 and strain 90032 are about 100%, the sequence similarity of 15 of all the 22 strains such as strain92101 and strain91066 are more than 99%; Strain 90012 and strain 92041are similar to Mx. flavescens NBRC 100081T and their sequence similarities are 100%, strain 94009 is similar to Mx. flavescens NBRC 100081T with the similarity over 99%; Strain 92086, strain 92122 and strain 91040 are similar to Mx. virescens DSM 2260T and their sequence similarities are 100%,99.93%,97.79% respectively.To confirm the relationship of the 28 strains of Myxococcus,10 strains were studied by the DNA-DNA hybridization. The final results show: each DNA-DNA similarity between the 5 strains92101、92103、92109、94102、91066 and the strain WH114s-1 are about 86%,83%,72%,95% and 94%,so they are belonging to the same species of Myxococcus; DNA-DNA similarity between strain 94009 and strain 92041 are about 75%, so they are belonging to the same species of Myxococcus, DNA-DNA similarity between strain 90012 and strain 94009 are only about 15%, so they are not belonging to the same species of Myxococcus. DNA-DNA similarity between strain 92006 and strain 90012 are about 80%, so they are belonging to the same species of Myxococcus. To identify the species of the strains of myxobacteria or whether it was belong to a new species of Myxococcus, studying by the DNA-DNA hybridization between the tested strains and the standard strains should be used.DNA G+Cmol% of the most strains was between 68% and 72%, which are consist to the crosponding genus respectively.In addition, physiological and biochemical characteristics of 8 strains which were chosen concerning experienments were similar to each other, but there were something different exist, too. So physiological and biochemical characteristics have some value to identify the species of the strains of myxobacteria.160 myxobacteria strains which are preserved by using the VY/2 slant preservation method were used in the study of the preservation duration of the method. The results show that the preservation duration of the method which is different in different genus could be best in a year.