Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1999 Aug;1(4):357-67.
doi: 10.1046/j.1462-2920.1999.00045.x.

Novel bacterial endosymbionts of Acanthamoeba spp. related to the Paramecium caudatum symbiont Caedibacter caryophilus

M Horn  1 , T R Fritsche, R K Gautom, K H Schleifer, M Wagner
Affiliations

Novel bacterial endosymbionts of Acanthamoeba spp. related to the Paramecium caudatum symbiont Caedibacter caryophilus

M Horn et al. Environ Microbiol. 1999 Aug.

Abstract

Acanthamoebae are increasingly being recognized as hosts for obligate bacterial endosymbionts, most of which are presently uncharacterized. In this study, the phylogeny of three Gram-negative, rod-shaped endosymbionts and their Acanthamoeba host cells was analysed by the rRNA approach. Comparative analyses of 16S rDNA sequences retrieved from amoebic cell lysates revealed that the endosymbionts of Acanthamoeba polyphaga HN-3, Acanthamoeba sp. UWC9 and Acanthamoeba sp. UWE39 are related to the Paramecium caudatum endosymbionts Caedibacter caryophilus, Holospora elegans and Holospora obtusa. With overall 16S rRNA sequence similarities to their closest relative, C. caryophilus, of between 87% and 93%, these endosymbionts represent three distinct new species. In situ hybridization with fluorescently labelled endosymbiont-specific 16S rRNA-targeted probes demonstrated that the retrieved 16S rDNA sequences originated from the endosymbionts and confirmed their intracellular localization. We propose to classify provisionally the endosymbiont of Acanthamoeba polyphaga HN-3 as 'Candidatus Caedibacter acanthamoebae', the endosymbiont of Acanthamoeba sp. strain UWC9 as 'Candidatus Paracaedibacter acanthamoebae' and the endosymbiont of Acanthamoeba sp. strain UWE39 as 'Candidatus Paracaedibacter symbiosus'. The phylogeny of the Acanthamoeba host cells was analysed by comparative sequence analyses of their 18S rRNA. Although Acanthamoeba polyphaga HN-3 clearly groups together with most of the known Acanthamoeba isolates (18S rRNA sequence type 4), Acanthamoeba sp. UWC9 and UWE39 exhibit <92% 18S rRNA sequence similarity to each other and to other Acanthamoeba isolates. Therefore, we propose two new sequence types (T13 and T14) within the genus Acanthamoeba containing, respectively, Acanthamoeba sp. UWC9 and Acanthamoeba sp. UWE39.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

MeSH terms

LinkOut - more resources