Saccamoeba lacustris, sp. nov. (Amoebozoa: Lobosea: Hartmannellidae), a new lobose amoeba, parasitized by the novel chlamydia ‘Candidatus Metachlamydia lacustris’ (Chlamydiae: Parachlamydiaceae) (original) (raw)
Related papers
Saccamoeba limax amoebae isolated from an aquatic biotope were found to harbor two different endocytic bacteria. By means of electron microscopy it could be shown that the first one was a rod-shaped Gram-negative bacterium considered as an endosymbiont. The second one developed elementary bod-ies (EBs) and reticulate stages (RBs) which are characteristic of Chlamydia-like bacteria, such as Parachlamydi-aceae, which are known to replicate within free-living amoebae (FLA). Cocul-tivation assays with various FLA re-vealed a high degree of host specificity.
2020
SummaryAmoebae interact with bacteria in diverse and multifaceted ways. Amoeba predation can serve as a selective pressure for the development of bacterial virulence traits. Bacteria may also adapt to life inside amoebae, resulting in symbiotic relationships (pathogenic or mutualistic). Indeed, particular lineages of obligate bacterial endosymbionts have been found in different amoebae. Here, we screened an extensive collection of Dictyostelium discoideum wild isolates for the presence of such bacterial symbionts using PCR primers that identify these endosymbionts. This is the first report of obligate symbionts in this highly-studied amoeba species. They are surprisingly common, identified in 42% of screened isolates (N=730). Members of the Chlamydiae phylum are particularly prevalent, occurring in 27% of the host strains. They are novel and phylogenetically distinct. We also found Amoebophilus symbionts in 8% of screened isolates (N=730). Antibiotic-cured amoebae behave similarly t...
Vannellalike amoebae, which were isolated from Elo dea sp. purchased through a mailorder company, were found to harbor two strains of endocytic bacteria. Al though the original host culture died out because of a massive infection, a Saccamoeba strain grown from the same sample proved susceptible to the endocytobionts and served as a wet nurse for the studies described herein. Electron microscopy showed that the first en docytobiont was a Chlamydialike bacterium because it produced elementary and reticulate bodies character istic of Chlamydiales. The second endocytobiont also exhibited dimorphic Gramnegative stages with round to oval shapes that were different from the shapes of the first endocytobiont. In addition, the Chlamydialike bacterium was found to harbor bacteriophages that we have tentatively named NeoPh3. Cocultivation assays with various freeliving amoebae showed that the en docytobionts exhibited a high degree of host specificity. Only amoebae of the genus Sa...