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.
- MeSH
- Chlamydiales klasifikace genetika izolace a purifikace MeSH
- fylogeneze MeSH
- hybridizace in situ fluorescenční MeSH
- jezera mikrobiologie MeSH
- ostrovy MeSH
- RNA ribozomální 16S genetika MeSH
- roční období MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- ostrovy MeSH
Amoebae play an important ecological role as predators in microbial communities. They also serve as niche for bacterial replication, harbor endosymbiotic bacteria and have contributed to the evolution of major human pathogens. Despite their high diversity, marine amoebae and their association with bacteria are poorly understood. Here we describe the isolation and characterization of two novel marine amoebae together with their bacterial endosymbionts, tentatively named 'Candidatus Occultobacter vannellae' and 'Candidatus Nucleophilum amoebae'. While one amoeba strain is related to Vannella, a genus common in marine habitats, the other represents a novel lineage in the Amoebozoa. The endosymbionts showed only low similarity to known bacteria (85-88% 16S rRNA sequence similarity) but together with other uncultured marine bacteria form a sister clade to the Coxiellaceae. Using fluorescence in situ hybridization and transmission electron microscopy, identity and intracellular location of both symbionts were confirmed; one was replicating in host-derived vacuoles, whereas the other was located in the perinuclear space of its amoeba host. This study sheds for the first time light on a so far neglected group of protists and their bacterial symbionts. The newly isolated strains represent easily maintainable model systems and pave the way for further studies on marine associations between amoebae and bacterial symbionts.
- MeSH
- Amoeba klasifikace mikrobiologie MeSH
- buněčné jádro mikrobiologie MeSH
- cytoplazma mikrobiologie MeSH
- druhová specificita MeSH
- Gammaproteobacteria klasifikace izolace a purifikace fyziologie MeSH
- symbióza fyziologie MeSH
- vodní organismy klasifikace izolace a purifikace mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
