title: A study on the presence of flagella in the order Rickettsiales: the case of 'Candidatus Midichloria mitochondrii'.
abstract: According to Bergey's Manual of Systematic Bacteriology, the Rickettsiales are '…bacteria with typical gram-negative cell walls and no flagella'. The recently sequenced genome of 'Candidatus Midichloria mitochondrii', a divergent lineage within the order Rickettsiales capable of invading mitochondria in ixodid ticks, revealed the presence of 26 putative flagellar genes. Open questions in relation to this observation are whether these genes are expressed and whether they possess the domains expected for the flagellar function. Here we show that: (a) the putative flagellar proteins of 'Ca. M. mitochondrii' actually possess the conserved domains and structural features required for their function in a model bacterium; (b) the seven flagellar genes of 'Ca. M. mitochondrii' that have been tested are expressed at the RNA level; and (c) the putative flagellar cap gene of this bacterium (FliD) is expressed at the protein level, and can be stained within the bacterium and at its surface. Beside the specific questions that we have addressed that relate to the first evidence, to our knowledge, for a flagellar apparatus in a member of the order Rickettsiales, we present here novel tools (recombinant protein and antibodies) that will facilitate the study of 'Ca. M. mitochondrii'.
authors.affiliation: Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, via Celoria 10, Milan, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Mariconti
authors.affiliation: Dipartimento di Medicina Sperimentale e Sanità Pubblica, Università di Camerino, via Gentile III da Varano, Camerino, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Epis
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Università di Pavia, via Ferrata 9, Pavia, Italy.
authors.forename: Luciano
authors.initials: L
authors.lastname: Sacchi
authors.affiliation: Dipartimento di Biologia e Biotecnologie, Università di Pavia, via Ferrata 9, Pavia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Biggiogera
authors.affiliation: Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, via Celoria 10, Milan, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Sassera
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Strada Campeggi 59/61, Pavia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Genchi
authors.affiliation: Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, via Celoria 10, Milan, Italy.
authors.forename: Eric
authors.initials: E
authors.lastname: Alberti
authors.affiliation: Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, via Celoria 10, Milan, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Montagna
authors.affiliation: Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, via Celoria 10, Milan, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Bandi
authors.affiliation: Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, via Celoria 10, Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Bazzocchi
mesh_terms: D020561:Alphaproteobacteria / Q000502:physiology*; D000818:Animals; D005407:Flagella / Q000502:physiology*; D005408:Flagellin / Q000096:biosynthesis* / Q000235:genetics*; D020869:Gene Expression Profiling; D008928:Mitochondria / Q000382:microbiology; D013987:Ticks / Q000382:microbiology
chemical_list: D005408:Flagellin