0000000000725459
AUTHOR
Davide Sassera
Phylogenomic evidence for the presence of a flagellum and cbb(3) oxidase in the free-living mitochondrial ancestor.
The initiation of the intracellular symbiosis that would give rise to mitochondria and eukaryotes was a major event in the history of life on earth. Hypotheses to explain eukaryogenesis fall into two broad and competing categories: those proposing that the host was a phagocytotic proto-eukaryote that preyed upon the free-living mitochondrial ancestor (hereafter FMA), and those proposing that the host was an archaebacterium that engaged in syntrophy with the FMA. Of key importance to these hypotheses are whether the FMA was motile or nonmotile, and the atmospheric conditions under which the FMA thrived. Reconstructions of the FMA based on genome content of Rickettsiales representatives-gener…
Description of Klebsiella spallanzanii sp. nov. and of Klebsiella pasteurii sp. nov
AbstractKlebsiella oxytocacauses opportunistic human infections and post-antibiotic haemorrhagic diarrhoea. ThisEnterobacteriaceaespecies is genetically heterogeneous and is currently subdivided into seven phylogroups (Ko1 to Ko4, Ko6 to Ko8). Here we investigated the taxonomic status of phylogroups Ko3 and Ko4. Genomic sequence-based phylogenetic analyses demonstrate that Ko3 and Ko4 formed well-defined sequence clusters related to, but distinct from,Klebsiella michiganensis(Ko1),Klebsiella oxytoca(Ko2),K. huaxiensis(Ko8) andK. grimontii(Ko6). The average nucleotide identity of Ko3 and Ko4 were 90.7% withK. huaxiensisand 95.5% withK. grimontii, respectively. In addition, three strains ofK.…