Diversity Of Bacteria Isolated From Periplaneta Americana Adult Gut

The insect is one of the largest groups in the animal kingdom which has over 1 million kinds of existing. Insect resources in China is quite rich, accounts for about 10% of the total number of the insects. Symbiotic insects may be a new wide sources of natural products and important source of new bioactive natural products, but the research of insect gut microbes was owed system and in-depth, scattering in only a few insect species, such as scorpions, bees. Detailed research mainly concentrated in the termite, the key crop pests, and so on, but Periplaneta americana gut microbes research rarely reported.This research mainly uses the numerical taxonomy, BOX-PCR, PCR-RFLP and phylogenetic analysis of 16S rRNA gene sequences and culture-independent method to study diversity of endophytic bacteria in the sample. The results show that the Periplaneta americana adult gut has relatively abundant bacterial diversity. The main results were as follows:Numerical taxonomy analysis results show that the 32 representative strains can be divided into 12 phenotypic group on the 82% similarity level, while group of 11 is one of the biggest groups, which has 14 strains of bacteria and representative strains SCAU13, SCAU78, SCAU23, SCAU75, SCAU9, SCAU92 composed separate groups, respectively.In the PCR-RFLP analysis, HaeⅢ has eight types of enzyme map and Hinfl has 7 types of enzyme map and TaqⅠ has 3 types of enzyme map and MspⅠ has 2 types of enzyme map types after four kinds of restriction enzymes (HaeⅢ, Hinfl, TaqⅠ, MspⅠ) processing, so we can say that HaeⅢ is more effect in the study of bacterial diversity.In BOX-PCR analysis, all the strains gathered at 72% similarity level and could be divided into 10 groups at 86% of similar level. In 10 genetic group, the largest group was group II which including a total of 23 strains, followed by group IV, composed of 7 strains.With sequencing comparison,32 isolates represented 20 species, belonging to 15 genera of 10 families in four phylogenetic groups (Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria). The most abundant and diverse isolates were within the Proteobacteria (15 strains,46.9%) and the Bacteroidetes (10 strains,31.3%).In free culture analysis, similarity comparison analysis shows that the 26 OTU belonging to 13 genera of 8 families in four phylogenetic groups (Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria). The most strains belong to the Proteobacteria (56.9%) and Bacteroidetes (21.4%), followed by Firmicutes (18.8%) and unclassified bacteria (1.6%).To sum up the results from the two methods, the bacteria in Periplaneta americana intestine belonging to 18 genera and some uncultured species. Overall, the study results presented above demonstrated that there are abundant bacteria diversity in the Periplaneta americana adult gut.