title: Ultrastructural and molecular identification of a new Rickettsia endosymbiont in the springtail Onychiurus sinensis (Hexapoda, Collembola).
abstract: In this paper we provide microscopic and molecular evidence for the presence of an endosymbiontic bacterium in male and female gonads of the soil arthropod Onychiurus sinensis. The sequence of the gene encoding for the 16S rRNA shows that the bacterium is a member of the genus Rickettsia, and some anomalies presumably associated with the presence of these microorganisms have been detected. Although the Rickettsia found in O. sinensis has the smallest genetic divergence with Rickettsia bellii, the phylogenetic analysis fails to find support for a sister-group relationship between these two species, rather suggesting that most Rickettsia species/strains isolated in various arthropods have rapidly evolved and diversified in what appears to be a sudden burst of evolution.
authors.affiliation: Dipartimento di Biologia Evolutiva, Università di Siena, Italy. frati@unisi.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Frati
authors.forename: Ilaria
authors.initials: I
authors.lastname: Negri
authors.forename: Pietro Paolo
authors.initials: PP
authors.lastname: Fanciulli
authors.forename: Marco
authors.initials: M
authors.lastname: Pellecchia
authors.forename: Romano
authors.initials: R
authors.lastname: Dallai
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D006066:Gonads / Q000382:microbiology* / Q000648:ultrastructure; D007313:Insecta / Q000382:microbiology*; D016013:Likelihood Functions; D008297:Male; D046529:Microscopy, Electron, Transmission; D010802:Phylogeny; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012281:Rickettsia / Q000235:genetics* / Q000302:isolation & purification / Q000648:ultrastructure*; D012282:Rickettsia Infections / Q000235:genetics / Q000382:microbiology* / Q000473:pathology; D012987:Soil; D013559:Symbiosis
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012987:Soil