Sassera, Davide

Publications (13)

“ Candidatus Midichloria” Endosymbionts Bloom after the Blood Meal of the Host, the Hard Tick Ixodes ricinus

Sassera et al. (2008). Applied and Environmental Microbiology 74 (19)
Names (1)
Ca. Midichloria
Applied Microbiology and Biotechnology Biotechnology Ecology Food Science
ABSTRACT “ Candidatus Midichloria mitochondrii,” an intracellular symbiont of the tick Ixodes ricinus , is the only described organism able to invade the mitochondria of any multicellular organism. We used quantitative PCR to examine cycles of bacterial growth and death throughout the host's development and found that they correspond with the phases of engorgement and molt, respectively.

‘Candidatus Midichloria mitochondrii’, an endosymbiont of the tick Ixodes ricinus with a unique intramitochondrial lifestyle

Sassera et al. (2006). International Journal of Systematic and Evolutionary Microbiology 56 (11)
Names (2)
Ca. Midichloria Ca. Midichloria mitochondrii
Ecology, Evolution, Behavior and Systematics General Medicine Microbiology
An intracellular bacterium with the unique ability to enter mitochondria exists in the European vector of Lyme disease, the hard tick Ixodes ricinus. Previous phylogenetic analyses based on 16S rRNA gene sequences suggested that the bacterium formed a divergent lineage within the Rickettsiales (Alphaproteobacteria). Here, we present additional phylogenetic evidence, based on the gyrB gene sequence, that confirms the phylogenetic position of the bacterium. Based on these data, as well as electron microscopy (EM), in situ hybridization and other observations, we propose the name ‘Candidatus Midichloria mitochondrii’ for this bacterium. The symbiont appears to be ubiquitous in females of I. ricinus across the tick's distribution, while lower prevalence is observed in males (44 %). Based on EM and in situ hybridization studies, the presence of ‘Candidatus M. mitochondrii’ in females appears to be restricted to ovarian cells. The bacterium was found to be localized both in the cytoplasm and in the intermembrane space of the mitochondria of ovarian cells. ‘Candidatus M. mitochondrii’ is the first bacterium to be identified that resides within animal mitochondria.