“Candidatus Trichorickettsia mobilis”, a Rickettsiales bacterium, can be transiently transferred from the unicellular eukaryote Paramecium to the planarian Dugesia japonica

Modeo, Letizia; Salvetti, Alessandra; Rossi, Leonardo; Castelli, Michele; Szokoli, Franziska; Krenek, Sascha; Serra, Valentina; Sabaneyeva, Elena; G, Di Giuseppe; Si, Fokin; Verni, Franco; Petroni, Giulio

doi:10.7717/peerj.8977

Cited by 10 publications

(5 citation statements)

References 104 publications

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“…Further remarks. Cryptic species; the closest related species is Paramecium multimicronucleatum ; may be discriminated from the latter by FISH; reported endosymbionts: “ Candidatus Trichorickettsia mobilis” [ 75 ].…”

Section: Discussionmentioning

confidence: 99%

Cryptic Diversity in Paramecium multimicronucleatum Revealed with a Polyphasic Approach

et al. 2022

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Paramecium (Ciliophora) systematics is well studied, and about twenty morphological species have been described. The morphological species may include several genetic species. However, molecular phylogenetic analyses revealed that the species diversity within Paramecium could be even higher and has raised a problem of cryptic species whose statuses remain uncertain. In the present study, we provide the morphological and molecular characterization of two novel Paramecium species. While Paramecium lynni n. sp., although morphologically similar to P. multimicronucleatum, is phylogenetically well separated from all other Paramecium species, Paramecium fokini n. sp. appears to be a cryptic sister species to P. multimicronucleatum. The latter two species can be distinguished only by molecular methods. The number and structure of micronuclei, traditionally utilized to discriminate species in Paramecium, vary not only between but also within each of the three studied species and, thus, cannot be considered a reliable feature for species identification. The geographic distribution of the P. multimicronucleatum and P. fokini n. sp. strains do not show defined patterns, still leaving space for a role of the geographic factor in initial speciation in Paramecium. Future findings of new Paramecium species can be predicted from the molecular data, while morphological characteristics appear to be unstable and overlapping at least in some species.

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Section: Discussionmentioning

confidence: 99%

Cryptic Diversity in Paramecium multimicronucleatum Revealed with a Polyphasic Approach

et al. 2022

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“…may have been maintained and have diverged inside diverse arthropod species through vertical transmissions (transovarial and trans-stadial). However, co-speciation between Rickettsia and arthropod species appears to be ruled out by the incongruence of phylogenetic trees 31 , 46 . Moreover, some Rickettsia spp.…”

Section: Discussionmentioning

confidence: 99%

Genomic evolution and adaptation of arthropod-associated Rickettsia

Karkouri

Ghigo

Raoult

et al. 2022

Sci Rep

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Rickettsia species are endosymbionts hosted by arthropods and are known to cause mild to fatal diseases in humans. Here, we analyse the evolution and diversity of 34 Rickettsia species using a pangenomic meta-analysis (80 genomes/41 plasmids). Phylogenomic trees showed that Rickettsia spp. diverged into two Spotted Fever groups, a Typhus group, a Canadensis group and a Bellii group, and may have inherited their plasmids from an ancestral plasmid that persisted in some strains or may have been lost by others. The results suggested that the ancestors of Rickettsia spp. might have infected Acari and/or Insecta and probably diverged by persisting inside and/or switching hosts. Pangenomic analysis revealed that the Rickettsia genus evolved through a strong interplay between genome degradation/reduction and/or expansion leading to possible distinct adaptive trajectories. The genus mainly shared evolutionary relationships with α-proteobacteria, and also with γ/β/δ-proteobacteria, cytophagia, actinobacteria, cyanobacteria, chlamydiia and viruses, suggesting lateral exchanges of several critical genes. These evolutionary processes have probably been orchestrated by an abundance of mobile genetic elements, especially in the Spotted Fever and Bellii groups. In this study, we provided a global evolutionary genomic view of the intracellular Rickettsia that may help our understanding of their diversity, adaptation and fitness.

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“…However, most of the bacteria seemed to remain intact, which is in good agreement with the recent finding that Ca. T. mobilis can survive in the planarian enterocytes for 7 days (Modeo et al, 2020). We suppose that egress of Ca.…”

Section: The Nature Of the Endosymbiont-containing Vacuoles In Ampicimentioning

confidence: 99%

A Robust Symbiotic Relationship Between the Ciliate Paramecium multimicronucleatum and the Bacterium Ca. Trichorickettsia Mobilis

Mironov

Sabaneyeva

2020

Front. Microbiol.

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Close reciprocal interactions in symbiotic systems have suggested the holobiont concept, in which the host and its microbiota are considered as a single entity. Ciliates are known for their ability to form symbiotic associations with prokaryotes. Relationships between the partners in such systems vary from mutualism to parasitism and differ significantly in their robustness. We assessed the viability of the ciliate Paramecium multimicronucleatum and its ability to maintain its intranuclear endosymbiont Ca. Trichorickettsia mobilis (Rickettsiaceae) after treatment with antibiotics characterized by different mode of action, such as ampicillin, streptomycin, chloramphenicol, tetracycline. The presence of endosymbionts in the host cell was determined by means of living cell observations made using differential interference contrast or fluorescence in situ hybridization with the species-specific oligonucleotide probe (FISH). Administration of antibiotics traditionally used in treatments of rickettsioses, tetracycline and chloramphenicol, depending on the concentration used and the ciliate strain treated, either caused death of both, infected and control cells, or did not affect the ability of the host to maintain the intranuclear endosymbiont. The surviving cells always manifested motile bacteria in the macronucleus. Streptomycin treatment never led to the loss of endosymbionts in any of the four infected strains, and nearly all ciliates remained viable. Ampicillin treatment never caused host cell death, but resulted in formation of filamentous and immobile oval bacterial forms. Under repeated ampicillin treatments, a part of endosymbionts was registered in the host cytoplasm, as evidenced both by FISH and transmission electron microscopy. Endosymbionts located in the host cytoplasm were enclosed in vacuoles, apparently, corresponding to autophagosomes. Nevertheless, the bacteria seemed to persist in this compartment and might cause relapse of the infection. Although the antibiotic sensitivity profile of Trichorickettsia seems to resemble that of other representatives of Rickettsiaceae, causative agents of severe diseases in humans, neither of the antibiotic treatments used in this study resulted in an aposymbiotic cell line, apparently, due to the protists’ sensitivity to tetracyclines, the drugs of preference in rickettsiosis treatment. The observed robustness of this symbiotic system makes it a good model for further elaboration of the holobiont concept.

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“Candidatus Trichorickettsia mobilis”, a Rickettsiales bacterium, can be transiently transferred from the unicellular eukaryote Paramecium to the planarian Dugesia japonica

Cited by 10 publications

References 104 publications

Cryptic Diversity in Paramecium multimicronucleatum Revealed with a Polyphasic Approach

Cryptic Diversity in Paramecium multimicronucleatum Revealed with a Polyphasic Approach

Genomic evolution and adaptation of arthropod-associated Rickettsia

A Robust Symbiotic Relationship Between the Ciliate Paramecium multimicronucleatum and the Bacterium Ca. Trichorickettsia Mobilis

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