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Paramecium bursaria—A Complex of Five Cryptic Species: Mitochondrial DNA COI Haplotype Variation and Biogeographic Distribution

by Magdalena Greczek-Stachura, Maria Rautian and Sebastian Tarcz

Diversity 2021, 13(11), 589; https://doi.org/10.3390/d13110589 - 18 Nov 2021

Cited by 13 | Viewed by 3550

Abstract

Ciliates are a diverse protistan group and many consist of cryptic species complexes whose members may be restricted to particular biogeographic locations. Mitochondrial genes, characterized by a high resolution for closely related species, were applied to identify new species and to distinguish closely related morphospecies. In the current study, we analyzed 132 sequences of COI mtDNA fragments obtained from P. bursaria species collected worldwide. The results allowed, for the first time, to generate a network of COI haplotypes and demonstrate the relationships between P. bursaria strains, as well as to confirm the existence of five reproductively isolated haplogroups. The P. bursaria haplogroups identified in the present study correspond to previously reported syngens (R1, R2, R3, R4, and R5), thus we decided to propose the following binominal names for each of them: P. primabursaria, P. bibursaria, P. tribursaria, P. tetrabursaria, and P. pentabursaria, respectively. The phylogeographic distribution of P. bursaria species showed that P. primabursaria and P. bibursaria were strictly Eurasian, except for two South Australian P. bibursaria strains. P. tribursaria was found mainly in Eastern Asia, in two stands in Europe and in North America. In turn, P. tetrabursaria was restricted to the USA territory, whereas P. pentabursaria was found in two European localities. Full article

(This article belongs to the Special Issue Cryptic Biodiversity in Freshwater Ecosystems)

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14 pages, 886 KiB

Open AccessReview

Mimiviridae: An Expanding Family of Highly Diverse Large dsDNA Viruses Infecting a Wide Phylogenetic Range of Aquatic Eukaryotes

by Jean-Michel Claverie and Chantal Abergel

Viruses 2018, 10(9), 506; https://doi.org/10.3390/v10090506 - 18 Sep 2018

Cited by 57 | Viewed by 7804

Abstract

Since 1998, when Jim van Etten’s team initiated its characterization, Paramecium bursaria Chlorella virus 1 (PBCV-1) had been the largest known DNA virus, both in terms of particle size and genome complexity. In 2003, the Acanthamoeba-infecting Mimivirus unexpectedly superseded PBCV-1, opening the era of giant viruses, i.e., with virions large enough to be visible by light microscopy and genomes encoding more proteins than many bacteria. During the following 15 years, the isolation of many Mimivirus relatives has made Mimiviridae one of the largest and most diverse families of eukaryotic viruses, most of which have been isolated from aquatic environments. Metagenomic studies of various ecosystems (including soils) suggest that many more remain to be isolated. As Mimiviridae members are found to infect an increasing range of phytoplankton species, their taxonomic position compared to the traditional Phycodnaviridae (i.e., etymologically “algal viruses”) became a source of confusion in the literature. Following a quick historical review of the key discoveries that established the Mimiviridae family, we describe its current taxonomic structure and propose a set of operational criteria to help in the classification of future isolates. Full article

(This article belongs to the Special Issue Algae Virus)

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