Midichlorian symbionts from ticks
Whilst screening for pathogens in Italian Ixodes ticks about a decade ago, we discovered a unique bacterial 16S rRNA sequence from within the alphaproteobacterial order Rickettsiales. We later characterised the bacterium associated with this sequence using electron microscopy, in situ hybridisation, and by examining its prevalence in ticks across Europe. In Ixodes ricinus, the bacterium appears to be facultative mutualist, that is notable in its capacity to invade the mitochondria of its host. We named the bacterium Midichloria mitochondrii. In 2013, we sequenced its genome, and detected some genes that have interesting implications for the origins of eukaryotes. Most recently, we have blocked the amplification of M. mitochondrii in metabarcoding studies of Australian ticks in order to screen for candidate pathogens that may be associated with putative tick-borne illnesses.