title: Chlamydial seasonal dynamics and isolation of 'Candidatus Neptunochlamydia vexilliferae' from a Tyrrhenian coastal lake.
abstract: The Chlamydiae are a phylum of obligate intracellular bacteria comprising important human and animal pathogens, yet their occurrence in the environment, their phylogenetic diversity and their host range has been largely underestimated. We investigated the seasonality of environmental chlamydiae in a Tyrrhenian coastal lake. By catalysed reporter deposition fluorescence in situ hybridization, we quantified the small planktonic cells and detected a peak in the abundance of environmental chlamydiae in early autumn with up to 5.9 × 10(4) cells ml(-1) . Super-resolution microscopy improved the visualization and quantification of these bacteria and enabled the detection of pleomorphic chlamydial cells in their protist host directly in an environmental sample. To isolate environmental chlamydiae together with their host, we applied a high-throughput limited dilution approach and successfully recovered a Vexillifera sp., strain harbouring chlamydiae (93% 16S rRNA sequence identity to Simkania negevensis), tentatively named 'Candidatus Neptunochlamydia vexilliferae'. Transmission electron microscopy in combination with fluorescence in situ hybridization was used to prove the intracellular location of these bacteria representing the first strain of marine chlamydiae stably maintained alongside with their host in a laboratory culture. Taken together, this study contributes to a better understanding of the distribution and diversity of environmental chlamydiae in previously neglected marine environments.
authors.affiliation: Water Research Institute, IRSA-CNR, via Salaria km 29,300, 00015 Monterotondo, Roma, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Pizzetti
authors.affiliation: University of Vienna, Department of Microbiology and Ecosystem Science, Althanstrasse 14, A-1090, Vienna, Austria.
authors.forename: Frederik
authors.initials: F
authors.lastname: Schulz
authors.affiliation: University of South Bohemia, Faculty of Science, Branišovská 31, 370 05, České Budějovice, Czech Republic.|Masaryk University, Department of Botany and Zoology, Faculty of Science, Kotlářská 2, 61137, Brno, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Tyml
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, D-28359, Bremen, Germany.
authors.forename: Bernhard M
authors.initials: BM
authors.lastname: Fuchs
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, D-28359, Bremen, Germany.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Amann
authors.affiliation: University of Vienna, Department of Microbiology and Ecosystem Science, Althanstrasse 14, A-1090, Vienna, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Horn
authors.affiliation: Water Research Institute, IRSA-CNR, via Salaria km 29,300, 00015 Monterotondo, Roma, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Fazi
mesh_terms: D002695:Chlamydiales / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017404:In Situ Hybridization, Fluorescence; D062312:Islands; D060106:Lakes / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012621:Seasons
chemical_list: D012336:RNA, Ribosomal, 16S