Analysis Of 16S RDNA Sequences And Biochemical Characteristics Of Enterococcus Isolated From The Silkworm, Bombyx Mori

asdfgFive Enterococcus strains, namely C1,FD,GC,F1-4 and A20, were isolated from the midgut of the silkworm. Among them, F1-4 could inhibit the spore germination of Nosema bombycis. The biochemical characteristics and 16S rDNA sequences analyses of all isolates were studied in this paper, and the sequence similarity was compared between the 16S rDNA and the species-specific probes of Enterococci. The aim of this study was to obtain some basic information for further studies on the diversity of Enterococcus and utilize the characteristics of Enterococcus effectively for biological control of pebrine.qwerThe genomic DNA of isolates was extracted by CTAB method, and universal primers of Enterococci were used to amplify the sequences of 16S rDNA, and then the results of PCR were sequenced. The 16S rDNA sequences of isolates were compared with the related genus or species in GenBank by BLAST software. 32 sequences of 16S rDNA of Enterococcus were taken from GenBank for phylogenetic analysis. Alignment of the 16S rDNA sequences was done by CLUSTAL X (1.8) package. Escherichia coli as an extra group, evolutionary distances were calculated by using Kuimura2-Parameter Distance model of MEGA software package version 2 and phylogenetic tree was constructed by Neighber-Joining Method. 1 000 samples were chosen randomly to calculate the bootstrap value for evaluating the confidence level of phylogenetic tree. The results of phylogenetic analysis of isolates indicated that the 16S rDNA were highly homologous to the sequence of Enterococcus mundtii AJ301836. The investigation of sequences of the species-specific probes for Enterococcus spp. revealed that the 16S rDNA sequences of isolates included the same sequence as the species-specific probe of Enterococcus mundtii Biochemical characteristics of all isolates except for A20 coincided with that of Enterococcus mundtii. It was concluded that Enterococcus mundtii existed in the midgut of the silkworm. It was the firt time that Enterococcus mundtii was detected in the silkworm midgut.