Analysis of DNA from Wolbachia infected Folsomia candida (Collembola: Isotomidae): evidence for a nucleolytic activity

Folsomia candida (Collembola: Isotomidae), a springtail that occurs commonly in soils throughout the world, is widely used in soil pollution and ecotoxicological studies. F. candida typically reproduces by parthenogenesis, which is widely believed to result from Wolbachia infection.  Wolbachia is a cytoplasmically transmitted alpha-proteobacterium that induces diverse reproductive alterations in its invertebrate hosts. In efforts to study Wolbachia, we observed that recovery of high quality DNA from springtails can be difficult, and that DNA prepared under typical extraction conditions contained a nuclease that inhibits amplification of DNA with Wolbachia primers.  We developed a biochemical assay showing that the activity degrades exogenous bacteriophage lambda DNA in biochemical reactions. The activity requires magnesium, has a broad pH optimum, is maximal at 45 °C, and is active on native polyacrylamide gels containing DNA stained with pyronin Y.  Efforts are underway to sequence peptides from the nuclease, and evaluate whether the activity is encoded by the Wolbachia or host genome.