All in the Fam­ily – An­other Up­date

by Elio

TEM of 'Can­di­da­tus Midichlo­ria mito­chondrii' in­side a mi­to­chon­drion. Court­esy of L. Sac­chi, Uni­ver­sity of Pavia, Italy.

One of the most cu­ri­ous phe­nom­ena we have re­ported here is that of bac­te­ria liv­ing in­side the mi­to­chon­dria of a tick. The name given to these bac­te­ria is Midichlo­ria mi­to­chon­drii (the genus name al­lud­ing to the midi-chlo­ri­ans in Star Wars). This sur­pris­ing find­ing was con­fined to a sin­gle species of hard ticks (Ixo­di­dae). A new re­port tells us that seven other species of re­lated ticks also dis­play this in­trigu­ing en­dosym­bio­sis. PCR analy­sis and some elec­tron mi­croscopy nailed down the pres­ence of the bac­te­ria, all closely re­lated to the orig­i­nal M. mi­to­chon­drii and mem­bers of the Rick­ettsiales – those mas­ters of host cell pen­e­tra­tion. So, the har­bor­ing of a bac­terium by an ex-bac­terium (the mi­to­chon­drion) may be more wide­spread than pre­vi­ously thought.

In a pre­vi­ous post, we dis­cussed a re­search re­port that pointed out how sim­i­lar the strat­egy used by these rick­ettsiae-like bac­te­ria to in­vade mi­to­chon­dria is to that of Bdellovib­rio prey­ing on free-liv­ing bac­te­ria.