CHLAREAS Chlamydia Research Association

Vandœuvre-lès-Nancy, France

CHLAREAS Chlamydia Research Association

Vandœuvre-lès-Nancy, France

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Corsaro D.,CHLAREAS Chlamydia Research Association | Corsaro D.,University of Neuchatel | Walochnik J.,Medical University of Vienna | Venditti D.,CHLAREAS Chlamydia Research Association | And 4 more authors.
Parasitology Research | Year: 2014

Molecular phylogenies based on the small subunit ribosomal RNA gene (SSU or 18S ribosomal DNA (rDNA)) revealed recently the existence of a relatively large and widespread group of eukaryotes, branching at the base of the fungal tree. This group, comprising almost exclusively environmental clones, includes the endoparasitic chytrid Rozella as the unique known representative. Rozella emerged as the first fungal lineage in molecular phylogenies and as the sister group of the Microsporidia. Here we report rDNA molecular phylogenetic analyses of two endonuclear parasites of free-living naked amoebae having microsporidia-like ultrastructural features but belonging to the rozellids. Similar to microsporidia, these endoparasites form unflagellated walled spores and grow inside the host cells as unwalled nonphagotrophic meronts. Our endonuclear parasites are microsporidia-like rozellids, for which we propose the name Paramicrosporidium, appearing to be the until now lacking morphological missing link between Fungi and Microsporidia. These features contrast with the recent description of the rozellids as an intermediate wall-less lineage of organisms between protists and true Fungi. We thus reconsider the rozellid clade as the most basal fungal lineage, naming it Rozellomycota. © 2014 Springer-Verlag.


Corsaro D.,CHLAREAS Chlamydia Research Association | Corsaro D.,University of Neuchatel | Walochnik J.,Medical University of Vienna | Venditti D.,CHLAREAS Chlamydia Research Association | And 2 more authors.
Acta Protozoologica | Year: 2013

A thermophilic strain of Naegleria clarki, isolated from a pond, has previously been investigated for its peculiarity to host a cytoplasmic symbiont, which causes a loss of the ability to form cysts. This endosymbiont, called Pcb, was itself infected by a phage, and exhibited chlamydia-like features resembling to another symbiont of Naegleria previously described as Protochlamydia naegleriophila. We report in this study, the results of amoeba host range and 16S rDNA molecular phylogeny of this strain, showing that Pcb is a new strain of the Naegleria endosymbiont chlamydial species Protochlamydia naegleriophila (Chlamydiae: Parachlamydiaceae).


Corsaro D.,CHLAREAS Chlamydia Research Association | Walochnik J.,Medical University of Vienna | Kohsler M.,Medical University of Vienna | Rott M.B.,Federal University of Rio Grande do Sul
Parasitology Research | Year: 2015

Acanthamoeba species are ubiquitous amoebae able to cause important infections in humans and other vertebrates. The full/near-full sequences (>2000 bp) of the small subunit ribosomal RNA gene (SSU rDNA or 18S rDNA) are used to cluster Acanthamoeba as genotypes, labeled T1 to T20. Genotype T15 remains an exception, being described only partially on a 1500-bp fragment. Strains are thus usually identified based on their 18S identity matches with reference strains, often using shorter (<500 bp) diagnostic fragments of the gene. Nevertheless, short fragments (<1000 bp) have been used to propose genotypes. This has been criticized, and doubts arise therefore on possible confusion leading to classify distinct partial sequences with a same label(s). We demonstrate herein that several partial sequences misassigned either to T16 or to T4, actually belong to at least two separate and distinct genotypes. We obtained the full 18S rDNA of a strain previously typed as T16 on the basis of a small fragment and demonstrated that it actually belongs to the recently described T19. We propose the name Acanthamoeba micheli sp. nov., for this strain. Furthermore, partial molecular phylogenies were performed to show that several other misassigned T16 partial sequences belong to a new genotype. This latter includes also misassigned T4 partial sequences, only recently available as full sequences and labeled as T20. We thus reassign these partial sequences to the genotype T20. Longer sequences, ideally at least 90 % of the total gene length, should be obtained from strains to ensure reliable diagnostic and phylogenetic results. © 2015, Springer-Verlag Berlin Heidelberg.


PubMed | Central Institute of the Federal Armed Forces Medical Services, Leibniz Institute for Baltic Sea Research, CHLAREAS Chlamydia Research Association and Medical University of Vienna
Type: | Journal: Parasitology research | Year: 2016

The genus Sappinia comprises free-living amoebae occurring worldwide in a variety of habitats such as soils, plant matter and freshwater ponds, but also animal faeces, and includes at present three species, S. pedata, S. diploidea and S. platani. The genus is potentially pathogenic, as indicated by the identification of S. pedata in a case of human amoebic encephalitis. Electron microscopy studies on some strains already revealed intracellular bacteria in Sappinia. In the current study, we performed 16S ribosomal RNA gene (rDNA) analysis of these bacterial endosymbionts. We first inferred relationships among Sappinia strains on the basis of 18S rDNA, demonstrating that S. pedata emerged as sister to a larger clade including S. diploidea, S. platani and a few S. diploidea-like strains. Thus, bacterial 16S rDNA was searched for in representative strains of each Sappinia species/subgroup. We found that Sappinia strains were associated to distinct species of Flavobacterium or Pedobacter (phylum Bacteroidetes). These appear to be distributed following the amoebal host subgroups, and are not directly related to other Bacteroidetes species known as interacting with free-living amoebae. While all the endosymbionts close relatives are known to grow on agar, bacteriological media inoculated with amoebal extracts remained negative. Overall, results indicate that the recovered bacteria are likely specific obligate endosymbionts of Sappinia species. Further studies, including additional amoebal strains and deep morphological and molecular analyses, will be necessary to confirm this hypothesis.


Corsaro D.,CHLAREAS Chlamydia Research Association | Corsaro D.,University of Neuchatel | Work T.M.,U.S. Geological Survey
Diseases of Aquatic Organisms | Year: 2012

The blue-striped snapper Lutjanus kasmira (Perciformes, Lutjanidae) are cosmopolitan in the Indo-Pacific but were introduced into Oahu, Hawaii, USA, in the 1950s and have since colonized most of the archipelago. Studies of microparasites in blue-striped snappers from Hawaii revealed chlamydia-like organisms (CLO) infecting the spleen and kidney, characterized by intracellular basophilic granular inclusions containing Gram-negative and Gimenez-positive bacteria similar in appearance to epitheliocysts when seen under light microscopy. We provide molecular evidence that CLO are a new member of Chlamydiae, i.e. Candidatus Renichlamydia lutjani, that represents the first reported case of chlamydial infection in organs other than the gill in fishes. © Inter-Research 2012.


Corsaro D.,University of Neuchatel | Corsaro D.,CHLAREAS Chlamydia Research Association | Venditti D.,CHLAREAS Chlamydia Research Association
Acta Protozoologica | Year: 2011

Strains of the genus Acanthamoeba are usually assigned to sequence types or genotypes according to pair-wise similarity valuesof the nuclear gene for the small subunit of ribosomal RNA. This classification system was established by comparing full or nearly full genesequences, > 2000 bp. For practical reasons, diagnostic fragments of smaller lengths have been identified and used for rapid and economicidentification of large number of strains. While the use of these small fragments in diagnostics applications remains valid when and onlyif the reference full sequence-type is available, we contest their use to identify and describe new genotypes. We report herein the case ofa new genotype described on the basis of solely a small partial sequence and discuss the poor reliability of this fragment to correctly inferphylogenetic relationships, and its limits in the description of new genotypes of Acanthamoeba.


Corsaro D.,CHLAREAS Chlamydia Research Association | Corsaro D.,University of Neuchatel | Venditti D.,CHLAREAS Chlamydia Research Association
Acta Protozoologica | Year: 2013

Some amoebae were recovered from freshwater samples on agar plates. Due to a fungal contamination tightly associated with these amoebae, it was impossible to correctly characterize them on a morphological base, but sequences of the small subunit ribosomal RNA gene (SSU rDNA) were successfully obtained from three strains. Phylogenetic analysis performed on these SSU rDNA allowed to identify these amoebae as members of a new lineage, related to the Dermamoebida, which includes also several other environmental SSU sequences.


PubMed | CHLAREAS Chlamydia Research Association
Type: Journal Article | Journal: Parasitology research | Year: 2014

Recent studies showed that the huge diversity branching at or near the phylogenetic root of the fungal kingdom, mostly constituted by uncultured environmental clones, is actually characterized by intracellular predators/parasites of various eukaryotes. These form three related lineages: the Aphelidea, endoparasites of algae; the Rozellomycota, with Rozella species mainly endoparasites of water moulds, and Paramicrosporidium species endonuclear parasites of amoebae; and the Microsporidia, mainly endoparasites of animals. Increasing evidence suggests the emergence of Microsporidia from within Rozellomycota; however, their fungal or protistan nature is still unclear. Here, we report the molecular phylogeny based on the small subunit ribosomal RNA (SSU rDNA) gene, of an additional endoparasite of amoebae, corresponding to the old enigmatic chytrid Nucleophaga amoebae described in the nineteenth century. Our results show that Nucleophaga, possessing a morphotype intermediate between Rozella and Paramicrosporidium, emerges as a unique lineage within the Rozellomycota. The recovery and characterization of new members of Rozellomycota are of high value for the understanding of the early evolutionary history of the Fungi and related lineages.


PubMed | CHLAREAS Chlamydia Research Association
Type: Journal Article | Journal: Folia microbiologica | Year: 2015

Chlamydiae are intracellular bacterial parasites of eukaryotes, ranging from amoebae to humans. They comprise many novel members and are investigated as emerging pathogens. Environmental studies highlighted similarities between the ecologies of chlamydiae and legionellae, both groups being important agents of respiratory infections. Herein, we analyzed nasal samples from healthy persons, searching for the presence of amoebae, chlamydiae and legionellae. From a total of 25 samples, we recovered by PCR eight samples positive to chlamydiae and six samples positive to legionellae. Among these samples, four were positive to both organisms. The sequencing of 16S rDNAs allowed to identify (i) among Chlamydiae: Parachlamydia acanthamoebae, Chlamydophila psittaci, Chlamydophila felis, and members of Rhabdochlamydiaceae, Simkaniaceae and E6 lineage and (ii) among Legionellaceae: Legionella longbeachae, Legionella bozemanii and Legionella impletisoli. Unexpectedly, we also recovered Diplorickettsia sp. Amoebae collected from nasal mucosae, Acanthamoeba and Vermamoeba, were endosymbiont-free, and chlamydiae revealed refractory to amoeba coculture. This study shows common exposure to chlamydiae and legionellae and suggests open air activities like gardening as a probable additional source of infection.


PubMed | CHLAREAS Chlamydia Research Association
Type: Journal Article | Journal: Parasitology research | Year: 2015

Acanthamoeba species are ubiquitous amoebae able to cause important infections in humans and other vertebrates. The full/near-full sequences (>2000bp) of the small subunit ribosomal RNA gene (SSU rDNA or 18S rDNA) are used to cluster Acanthamoeba as genotypes, labeled T1 to T20. Genotype T15 remains an exception, being described only partially on a 1500-bp fragment. Strains are thus usually identified based on their 18S identity matches with reference strains, often using shorter (<500bp) diagnostic fragments of the gene. Nevertheless, short fragments (<1000bp) have been used to propose genotypes. This has been criticized, and doubts arise therefore on possible confusion leading to classify distinct partial sequences with a same label(s). We demonstrate herein that several partial sequences misassigned either to T16 or to T4, actually belong to at least two separate and distinct genotypes. We obtained the full 18S rDNA of a strain previously typed as T16 on the basis of a small fragment and demonstrated that it actually belongs to the recently described T19. We propose the name Acanthamoeba micheli sp. nov., for this strain. Furthermore, partial molecular phylogenies were performed to show that several other misassigned T16 partial sequences belong to a new genotype. This latter includes also misassigned T4 partial sequences, only recently available as full sequences and labeled as T20. We thus reassign these partial sequences to the genotype T20. Longer sequences, ideally at least 90% of the total gene length, should be obtained from strains to ensure reliable diagnostic and phylogenetic results.

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