Diversity and Evolution of Paramoeba spp. and their Kinetoplastid Endosymbionts

Abstract

Members of the genus Paramoeba (including Neoparamoeba) (Amoebozoa) are single-celled eukaryotes of economic and ecological importance because of their association with disease in a variety of marine animals including fish, sea urchins, and lobster. Interestingly, they harbor a eukaryotic endosymbiont of kinetoplastid ancestry, Perkinsela sp. To investigate the complex relationship between Paramoeba spp. and Perkinsela sp., as well as the relationships between different Paramoeba species, molecular data was obtained for four novel isolates. We also acquired new data from the urchin pathogen P. invadens. Comprehensive molecular phylogenetic analyses were carried out using 33 newly obtained 18S rDNA sequences from the host amoebae and 16 new 18S rDNA sequences from their corresponding Perkinsela sp., together with all publicly available 18S molecular data. Intra-isolate 18S rDNA nucleotide diversity was found to be surprisingly high within the various species of Paramoeba, but relatively low within their Perkinsela sp. endosymbionts. 18S rDNA phylogenies and ParaFit co-evolution analysis revealed a high degree of congruence between the Paramoeba and Perkinsela sp. tree topologies, strongly suggesting that a single endosymbiotic event occurred in the common ancestor of known Paramoeba species, and that the endosymbionts have been inherited vertically ever since.

Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes

“…chaetognathi (Grassi 1881) and J. pigmentifera (Grassi 1881) are not triangular but monopodial in locomotion which may be a consequence of their parasitic life style. No molecular data on this genus are available, so it is left among the Dactylopodida provisionally, basing on the presence of a kinetoplastid intracellular symbiont (PLO), which appeares to have originated only once in the evolution of paramoebids (Sibbald et al 2017). 23 This genus may be a junior synonym of Vannella, being a life form of some Vannella species.…”

“…No molecular data on this genus are available, so it is left among the Dactylopodida provisionally, basing on the presence of a kinetoplastid intracellular symbiont (PLO), which appeares to have originated only once in the evolution of paramoebids (Sibbald et al. ). …”

A diversity of amoebae colonise the gills of farmed Atlantic salmon (Salmo salar) with amoebic gill disease (AGD)

“…group. The most recent phylogenetic models were used as the backbone to the analysis, which included those of Tyml and Dyková (2017) for Tubulinea, Sibbald et al, (2017), Kudryavtsev and Gladkikh, (2017) and Udalov et al, (2016) The sequence datasets were aligned in MAFFT v. 7 (Katoh et al, 2017) using the G-INS-I algorithm for the Tubulinea dataset, and the E-INS-I algorithm for the Discosea dataset. The alignments were trimmed using trimAl v.12 (Capella-Gutiérrez et al, 2009) with -gt 0.3 -st 0.001 restrictions for both the Tubulinea and Discosea analysis.…”

Genome sequencing reveals metabolic and cellular interdependence in an amoeba-kinetoplastid symbiosis

“…While molecular data suggest an ancient co-evolutionary relationship between Paramoeba / Neoparamoeba hosts and their Perkinsela sp. endosymbionts 15 – 17 , precisely when, how, and why the latter came to reside within the former is a long-standing mystery. Because the endosymbiont is non-photosynthetic—and thus unlike the algae involved in the spread of plastids (chloroplasts) by ‘secondary’ endosymbiosis 18 —it provides no obvious energetic benefit to its amoeba host.…”