Protistology 10 (1) 13–25 (2016) |
Diversity of symbiotic consortia of prokaryotes in the cells of pelomyxids (Archamoeba, Pelomyxidae) |
1 Core Facility Centre “Culturing of microorganisms”, St. Petersburg State University, Botanycheskaya str., St. Petersburg, 198504, Russia
Summary The family Pelomyxidae includes archamoebae of the genera Mastigella and Pelomyxa. In contrast to other archamoebae, they always contain prokaryotic cytobionts in their cytoplasm. According to the morphological analysis of the cytobionts in 11 pelomyxid species, we classified them into 4 basic types, namely: “Af”, “Lt”, “S3” and “S4”. Being specific for each host species, these cytobionts form constant consortia which can be of two kinds: binary and ternary. Only “Af” cytobionts are common for all pelomyxids. These are slim rod-shaped Grampositive bacteria autofluorescing in UV. They have electron-dense cytoplasm and distinctive pointed cell ends. We found population of pelomyxae P. belevskii (Lt-) that have only “Af” cytobionts in the cytoplasm. Since these bacteria are found in all studied representatives of Pelomyxidae – both in Mastigella and Pelomyxa – this may indicate the early origin of such symbiosis, presumably associated with the separation of the group from the common stem of archamoebae. The presence of at least two shared cytobionts (“Af” and “Lt”) in the prokaryotic consortia of Mastigella and Pelomyxa serves as an additional evidence in favour of possible phylogenetic proximity of these two archamoebal groups.
Key words: archamoebae, cytobionts, Mastigella, Pelomyxa, prokaryotic consortia, phylogeny
Address for correspondence: Alexey Y. Kostygov. Angliyskiy prosp. 32, 190121 St. Petersburg, Russia; e-mail: kostygov@gmail.com |
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