title: Symbiotic bacteria associated with stomach discs of human lice.
abstract: The symbiotic bacteria associated with the stomach disc, a large aggregate of bacteriocytes on the ventral side of the midgut, of human body and head lice were characterized. Molecular phylogenetic analysis of 16S rRNA gene sequences showed that the symbionts formed a distinct and well-defined clade in the Gammaproteobacteria. The sequences exhibited AT-biased nucleotide composition and accelerated molecular evolution. In situ hybridization revealed that in nymphs and adult males, the symbiont was localized in the stomach disc, while in adult females, the symbiont was not in the stomach disc but in the lateral oviducts and the posterior pole of the oocytes due to female-specific symbiont migration. We propose the designation "Candidatus Riesia pediculicola" for the louse symbionts.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8566, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Sasaki-Fukatsu
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Koga
authors.forename: Naruo
authors.initials: N
authors.lastname: Nikoh
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yoshizawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Kasai
authors.forename: Minoru
authors.initials: M
authors.lastname: Mihara
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Tomita
authors.forename: Takema
authors.initials: T
authors.lastname: Fukatsu
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D020563:Gammaproteobacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D009758:Nymph; D010374:Pediculus / Q000254:growth & development / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013270:Stomach / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S