Potential of symbionts in controlling arthropod-borne diseases

In addition to the analysis of the prokaryotic 16S ribosomal RNA gene (rDNA) conducted last year, we analyzed the eukaryotic flora that coexists with ticks. We have developed a method to suppress the amplification of tick-derived DNA by adding artificial nucleic acids (Locked Nucleic Acid (LNA) and Peptide Nucleic Acid (PNA)) specific to the tick 18S rDNA sequence to the PCR reaction solution. We also investigated a method for analyzing eukaryotic flora using primers specific to metazoans. When tested using three domestic ticks, almost all of the detected sequences were derived from ticks by the general PCR method, but the PCR method using PNA most effectively reduced the sequences derived from ticks. Various eukaryotes were detected. Even when a primer specific to metazoans was used, a decrease in tick-derived sequences was confirmed, but the result was that fungi were preferentially detected. Furthermore, when the PCR method using PNA was applied to 95 Japanese ticks of 18 species in 4 genera, pathogenic protozoans of the phylum Apicomplexa were detected in 42 individuals, and Gregarina, an arthropod symbiotic, further classified into the same phylum. Was detected in 17 individuals. In addition, a large number of reported protist and unclassified protist sequences were detected in soil and freshwater. In addition to the above, the entire genome sequences of tick symbiotic microorganisms (Spiroplasma bacterium and Rickettsiella bacterium) that have been successfully isolated and cultured have been decoded. In particular, the bacterium of the genus Rickettsiella is phylogenetically very closely related to the bacterium of the genus Coxiella analyzed last year, and we proceeded with the analysis of genes involved in vitamin metabolism. In addition, genes involved in tick antioxidants were knocked down by RNA technology to evaluate their effect on the bacterial flora. As a result of the analysis, no clear change in the microbial flora before and after the knockdown could be observed.

Dimensions project details

Measurement of Transmission

Apr 2019 — Mar 2022

$158,000

Japan
Sudan

Anopheles stephensi