Effect of fluoride on gut microflora of silkworm (Bombyx mori)

Abstract:

Abstract:［Objective］ We examined the effect of fluoride on gut microflora of silkworm.［Methods］ After DNA extraction and PCR amplification，clone libraries of 16S rRNA gene fragment were constructed． Amplified ribosomal DNA restriction analysis (ARDRA) was performed by digestion of the 16S rRNA gene，and each unique restriction fragment polymorphism pattern was designated as an operational taxonomic unit (OTU)．A total of 14 OTUs were identified from intestinal samples of both T6 and 734. Phylogenetic trees of bacterial 16S rRNA nucleotide sequences were constructed and analyzed． Furthermore，the dominant bacteria were studied by the nested polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DDGE) technology.［Results］After fluorosis，the flora of Enterococcus and Bacillus reduced． However，the flora of Staphylococcus increased.［Conclusion］Fluoride can destroy the balance of microflora in the gut of silkworm by changing the bacteria diversity and proportion，which has bigger effect to 734 than T6.

Key words:Keywords: Bombyx mori，fluoride，intestinal microflora，clone library，nested PCR-DGGE