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Microb Ecol ; 77(4): 1092-1106, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30627761


We characterized a novel Holospora-like bacterium (HLB) (Alphaproteobacteria, Holosporales) living in the macronucleus of the brackish water ciliate Frontonia salmastra. This bacterium was morphologically and ultrastructurally investigated, and its life cycle and infection capabilities were described. We also obtained its 16S rRNA gene sequence and performed in situ hybridization experiments with a specifically-designed probe. A new taxon, "Candidatus Hafkinia simulans", was established for this HLB. The phylogeny of the family Holosporaceae based on 16S rRNA gene sequences was inferred, adding to the already available data both the sequence of the novel bacterium and those of other Holospora and HLB species recently characterized. Our phylogenetic analysis provided molecular support for the monophyly of HLBs and placed the new endosymbiont as the sister genus of Holospora. Additionally, the host ciliate F. salmastra, recorded in Europe for the first time, was concurrently described through a multidisciplinary study. Frontonia salmastra's phylogenetic position in the subclass Peniculia and the genus Frontonia was assessed according to 18S rRNA gene sequencing. Comments on the biodiversity of this genus were added according to past and recent literature.

Holosporaceae/fisiologia , Peniculina/microbiologia , Simbiose , Holosporaceae/classificação , Holosporaceae/genética , Holosporaceae/ultraestrutura , Itália , Macronúcleo/microbiologia , Microscopia Eletrônica de Transmissão , Peniculina/fisiologia , Filogenia , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , RNA Ribossômico 18S/análise , Análise de Sequência de DNA
J Eukaryot Microbiol ; 47(4): 419-29, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11140457


Peniculine ciliates have been recognized as a distinct higher taxon of ciliates for almost 50 years. However, phylogenetic relationships within the Subclass Peniculia are still unsettled. To contribute to our understanding of their phylogeny and provide evidence for the position of Urocentrum turbo, we sequenced its small subunit (SS) rRNA gene and the SSrRNA genes from Lembadion bullinum, Frontonia sp., Paramecium caudatum, Paramecium multimicronucleatum, Paramecium putrinum, and Paramecium woodruffi. Urocentrum turbo was the only one of these species not to exhibit a shortened Helix E10_1, which we conclude characterizes the "higher" peniculines. Except for U. turbo, the peniculines are strongly supported as a monophyletic clade with Lembadion, Frontonia, and Paramecium species forming separate and strongly supported clades by bootstrap analysis using distance matrix, maximum parsimony, and maximum likelihood methods. Urocentrum turbo is associated with different lineages, depending upon the analysis used. The Paramecium species form at least four clades with the Paramecium aurelia subgroup being the most derived. We conclude that the Subclass Peniculia should be divided into two orders, the Order Urocentrida and Order Peniculida, with the latter order having two suborders, the Suborder Frontoniina and Peniculina. We place U. turbo with the peniculines because of shared morphological and stomatogenetic features.

Peniculina/classificação , Peniculina/genética , Filogenia , Animais , Sequência de Bases , DNA Ribossômico/análise , Genes de RNAr , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Paramecium/classificação , Paramecium/genética , Peniculina/química , RNA Ribossômico/genética , Análise de Sequência de DNA