Holospora-like bacteria "Candidatus Gortzia yakutica" and Preeria caryophila: Ultrastructure, promiscuity, and biogeography of the symbionts

Sergei I Fokin; Natalia A Lebedeva; Alexey Potekhin; Leandro Gammuto; Giulio Petroni; Valentina Serra

doi:10.1016/j.ejop.2023.125998

Holospora-like bacteria "Candidatus Gortzia yakutica" and Preeria caryophila: Ultrastructure, promiscuity, and biogeography of the symbionts

Eur J Protistol. 2023 Aug:90:125998. doi: 10.1016/j.ejop.2023.125998. Epub 2023 Jun 10.

Authors

Sergei I Fokin¹, Natalia A Lebedeva², Alexey Potekhin³, Leandro Gammuto¹, Giulio Petroni⁴, Valentina Serra¹

Affiliations

¹ Department of Biology, University of Pisa, Italy.
² Centre of Core Facilities "Culture Collections of Microorganisms", Saint Petersburg State University, Russia.
³ Laboratory of Cellular and Molecular Protistology, Zoological Institute of Russian Academy of Sciences, Saint Petersburg, Russia; Research Department for Limnology, University of Innsbruck, Mondsee, Austria.
⁴ Department of Biology, University of Pisa, Italy; CIME, Centro Interdipartimentale di Microscopia Elettronica, Università di Pisa, Pisa, Italy; CISUP, Centro per l'Integrazione della Strumentazione dell'Università di Pisa, Pisa, Italy.

PMID: 37356197
DOI: 10.1016/j.ejop.2023.125998

Abstract

Two already known representatives of Holospora-like bacteria, "Candidatus Gortzia yakutica" from Paramecium putrinum and Preeria caryophila, originally retrieved from the Paramecium aurelia complex, were found in new hosts: Paramecium nephridiatum and Paramecium polycaryum, respectively. In the present study, these bacteria were investigated using morphological and molecular methods. For "Ca. G. yakutica", the first details of the electron microscopic structure in the main and new hosts were provided. Regarding Pr. caryophila, the ultrastructural description of this species was implemented by several features previously unknown, such as the so called "membrane cluster" dividing periplasm from cytoplasm and fine composition of infectious forms before and during its releasing from the infected macronucleus. The new combinations of these Holospora-like bacteria with ciliate hosts were discussed from biogeographical and ecological points of view. Host specificity of symbionts as a general paradigm was critically reviewed as well.

Keywords: Ciliates; Host specificity; Molecular markers; Phylogeny; Symbiosis; Ultrastructure.

MeSH terms

Bacteria
Holosporaceae*
Macronucleus
Paramecium* / microbiology
Phylogeny
Symbiosis