CiteULike: di carpi endosymbiont

Infection and co-infection rates of Anaplasma phagocytophilum variants, Babesia spp., Borrelia burgdorferi, and the rickettsial endosymbiont in Ixodes scapularis (Acari: Ixodidae) from sites in Indiana, Maine, Pennsylvania, and Wisconsin.

FE Steiner — 2008-05-09T15:55:46-00:00

Journal of medical entomology, Vol. 45, No. 2. (March 2008), pp. 289-297.

In total, 394 questing adult blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), collected at four sites were analyzed by polymerase chain reaction (PCR) for five microbial species: Anaplasma phagocytophilum, Babesia microti, Babesia odocoilei, Borrelia burgdorferi, and the rickettsial I. scapularis endosymbiont. Identities of genetic variants of A. phagocytophilum were determined by sequencing a portion of the 16S DNA. In 55% of infected ticks (193/351), a single agent was detected. In 45% (158/351), two or more agents were detected; 37% harbored two agents and 8% harbored three agents. One male tick, collected from Ft. McCoy, WI, harbored all four microbial genera The highest rates of co-infection were by the Ixodes endosymbiont and B. burgdorferi (95/351). Two species of Babesia co-occurred within a single tick population in Wells National Estuarine Research Reserve, Wells, ME, whereas only B. odocoilei was found in other tick populations. Only A. phagocytophilum human anaplasmosis variant was detected in questing ticks from Tippecanoe River State Park, IN; from Wells; and Ft. McCoy, whereas a single infected tick from Presque Isle, PA, was infected by AP-Variant 1. Partially engorged ticks from deer in Tippecanoe River State Park were all infected with AP-Variant 1. Frequency of infections with each agent varied among populations. Rates and types of co-infections were not significantly different from random except for the Ixodes endosymbiont and B. burgdorferi in male ticks, which co-occurred less frequently than expected. Thus, I. scapularis hosts an array of pathogenic and symbiotic agents and potential evidence of interactions among microbial species was observed.

Symbiotic bacteria in oocyte and ovarian cell mitochondria of the tick Ixodes ricinus: biology and phylogenetic position

Rymaszewska — 2007-03-27T18:16:15-00:00

Parasitology Research, Vol. 100, No. 5. (April 2007), pp. 917-920.

Midichloria mitochondrii is widespread in hard ticks (Ixodidae) and resides in the mitochondria of phylogenetically diverse species.

S Epis — 2008-04-29T20:21:24-00:00

Parasitology, Vol. 135, No. 4. (April 2008), pp. 485-494.

The hard tick Ixodes ricinus (Ixodidae) is the sole animal thus far shown to harbour an intra-mitochondrial bacterium, which has recently been named Midichloria mitochondrii. The objectives of this work were (i) to screen ixodid ticks for Midichloria-related bacteria and (ii) to determine whether these bacteria exploit the intra-mitochondrial niche in other tick species. Our main goal was to discover further models of this peculiar form of symbiosis. We have thus performed a PCR screening for Midichloria-related bacteria in samples of ixodid ticks collected in Italy, North America and Iceland. A total of 7 newly examined species from 5 genera were found positive for bacteria closely related to M. mitochondrii. Samples of the tick species Rhipicephalus bursa, found positive in the PCR screening, were analysed with transmission electron microscopy, which revealed the presence of bacteria both in the cytoplasm and in the mitochondria of the oocytes. There is thus evidence that bacteria invade mitochondria in at least 2 tick species. Phylogenetic analysis on the bacterial 16S rRNA gene sequences generated from positive specimens revealed that the bacteria form a monophyletic group within the order Rickettsiales. The phylogeny of Midichloria symbionts and related bacteria does not appear completely congruent with the phylogeny of the hosts.

A novel alpha-Proteobacterium resides in the mitochondria of ovarian cells of the tick Ixodes ricinus.

T Beninati — 2008-04-29T20:12:05-00:00

Applied and environmental microbiology, Vol. 70, No. 5. (May 2004), pp. 2596-2602.

An intracellular bacterium from Ixodes ricinus ticks collected in Italy was characterized by electron microscopy (EM), PCR sequencing of the 16S rRNA gene, molecular phylogenetic analysis, and in situ hybridization (ISH). This bacterium was shown by EM to be present in the cytoplasm, as well as in the mitochondria of ovarian cells. When universal 16S rRNA bacterial primers were used, PCR amplification of ovarian DNA followed by cloning and sequencing resulted in the same sequence being found in each sample. Phylogenetic analysis of this sequence showed that the bacterium from which it was derived, tentatively designated IricES1, is part of a novel clade in the alpha subdivision of the Proteobacterium: ISH and PCR assays of various tissues performed with oligonucleotides specific for the IricES1 16S rRNA showed that IricES1 is restricted to ovarian cells. Based on the results obtained, we inferred that the bacteria seen by EM in ovarian cells are a single type of bacteria, corresponding to IricES1. PCR screening of 166 ticks from various parts of Italy and one site in England showed that IricES1 was present in 96% of adult females and 44% of nymphs (unsexed). No adult males were found to be infected. Despite the apparent parasitism of host mitochondria by IricES1, the available information suggests that the bacterium has an obligate relationship with its host, although this must be confirmed.

Diversity of Ixodes ricinus tick-associated bacterial communities from different forests.

Leo van Overbeek — 2008-04-17T15:12:03-00:00

FEMS microbiology ecology (18 March 2008)

Nymphal Ixodes ricinus ticks (n=180) were collected from three different areas in the Netherlands to investigate the effect of forest composition on tick-associated microbial communities. Sampled habitats differed in thickness of leaf litter and humus layers and vegetation associations and were located near Amsterdam (Beech-Oak), Ede (Birch-Oak) and Veldhoven (Birch-Oak). Analysis of nine 16S rRNA gene clone libraries made from individual ticks showed nearest matches with presumed pathogens Candidatus Neoehrlichia mikurensis and Rickettsia australis and arthropod endosymbionts Wolbachia pipientis and Candidatus Midichloria mitochondrii. Total bacterial species diversity (Shannon index) and Borrelia species infections were determined in I. ricinus by, respectively, PCR-denaturing gradient gel-electrophoresis and PCR-reverse line blot with probes specific for Borrelia burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii, Borrelia valaisiana, Borrelia lusitaniae and Borrelia ruski. Bacterial diversity differed significantly per area and was lowest in Ede. In contrast, Borrelia species-infected ticks were more abundant in Ede, Candidatus Neoehrlichia mikurensis-infected ticks in Ede and Veldhoven, and R. australis-infected ticks in Amsterdam. Borrelia afzelii was the most common Borrelia species found in all three areas. Bacterial tick diversity was influenced by local differences in forest structure, which is proposed to modulate animal populations that are commonly parasitized by I. ricinus.