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"Candidatus Midichloria" endosymbionts bloom after the blood meal of the host, the hard tick Ixodes ricinus.

Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Università degli Studi di Milano, Milan, Italy.
Applied and Environmental Microbiology (Impact Factor: 3.95). 09/2008; 74(19):6138-40. DOI: 10.1128/AEM.00248-08
Source: PubMed

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.

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Available from: Sara Epis, Jan 08, 2014
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    • "However, the available data regarding the localization of the M. mitochondrii population in the organs of immature stages of I. ricinus suggests the presence only in the primordia of the genital apparatus (Epis et al., 2013). Additionally the amount of M. mitochondrii found in larvae is known to be lower than the load of nymphs or adult females (Sassera et al., 2008). An alternative hypothesis could be that larvae can transmit M. mitochondrii but in quantity that are insufficient to be detected by our method. "
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    ABSTRACT: Midichloria mitochondrii is the most prevalent symbiont of the hard tick Ixodes ricinus, present in 100% of eggs and adult females of wild ticks. This bacterium is intracellular, and is the only known symbiont able to invade the mitochondria of the host cells. However, the role that M. mitochondrii plays in the host metabolism has yet to be elucidated. Multiple lines of evidence indicate the possibility of transmission of this bacterium to the vertebrate host during the tick blood meal. In order to investigate the role of M. mitochondrii in the biology of the tick host, we performed an antibiotic treatment on Ixodes ricinus individuals, with the aim of reducing/eliminating the symbiont, and to potentially observe the dynamic of bacterial infection in the tick host. We microinjected engorged adult females of I. ricinus with tetracycline, and we allowed the resulting larvae to feed on gerbils treated with the same antibiotic. The amount of M. mitochondrii was evaluated at different stages of the experiment using molecular techniques. In addition we evaluated the presence/absence of the symbiont DNA in the blood of gerbils used for the larval feeding. The performed treatments did not allow to eliminate the symbiont population from the host tick, however it allowed to reduce the multiplication that occurs after the larval blood meal. These results open the way for future experiments, using different antibiotic molecules, different administration methods and antibiotic administration on subsequent tick stages, to fulfill the goal of eliminating M. mitochondrii from the host I. ricinus, a major step in our understanding of the impact of this bacterium on ticks. Copyright © 2015 Elsevier GmbH. All rights reserved.
    Ticks and Tick-borne Diseases 05/2015; 6(5). DOI:10.1016/j.ttbdis.2015.05.011 · 2.88 Impact Factor
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    • "For example, Ixodes scapularis Say and Ixodes pacificus Cooley & Kohls each harbor genetically distinguishable Spotted Fever Group Rickettsia endosymbionts (Benson et al. 2004, Moreno et al. 2006, Steiner et al. 2008, Phan et al. 2011). The Ixodes ricinus (L.) endosymbiont Candidatus Midichloria mitochondrii has a unique localization to the mitochondria of I. ricinus ovarian cells (Beninati et al. 2004, Lo et al. 2006, Sassera et al. 2008). Dermacentor ticks (Niebylski et al. 1997a, Sun et al. 2000, Scoles 2004, Goethert and Telford 2005) and Amblyomma maculatum Koch (Scoles 2004) carry Francisella-like endosymbionts, and each species of tick has an endosymbiont with a distinct sequence. "
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    ABSTRACT: Many organisms, such as insects, filarial nematodes, and ticks, contain heritable bacterial endosymbionts that are often closely related to transmissible tickborne pathogens. These intracellular bacteria are sometimes unique to the host species, presumably due to isolation and genetic drift. We used a polymerase chain reaction/electrospray ionization-mass spectrometry assay designed to detect a wide range of vectorborne microorganisms to characterize endosymbiont genetic signatures from Amblyomma americanum (L.), Amblyomma maculatum Koch, Dermacentor andersoni Stiles, Dermacentor occidentalis Marx, Dermacentor variabilis (Say), Ixodes scapularis Say, Ixodes pacificus Cooley & Kohls, Ixodes ricinus (L.), and Rhipicephalus sanguineus (Latreille) ticks collected at various sites and of different stages and both sexes. The assay combines the abilities to simultaneously detect pathogens and closely related endosymbionts and to identify tick species via characterization of their respective unique endosymbionts in a single test.
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    • "om two adult females . Samples were treated with DNase I RNase free ( New England Biolabs ) for DNA contamination removal and quantified by spectrophotometry ; 500 ng each RNA was retrotranscribed to cDNA by using the QuantiTect Reverse Transcription kit ( Qiagen ) . The amplification of ' Ca . M . mitochondrii ' gyrB was performed as described by Sassera et al . ( 2008 ) to confirm the presence of the symbionts and the correct cDNA synthesis . Based on the available gene sequences , primers for the amplification of fragments of ' Ca . M . mitochondrii ' fliC , fliD , flgL , flgK , flgE , motA and fliG genes were designed . Primers are given in Table 1 . The expression of these genes in different tick "
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    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'.
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