Biology of Euplotes focardii, an Antarctic ciliate

Valbonesi, Alessandro; Luporini, Pierangelo

doi:10.1007/bf00233140

Cited by 36 publications

(46 citation statements)

References 8 publications

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“…The genetic procedure conventionally adopted to distinguish between these morphologically alike homo-and heterotypic pairs is the Mendelian analysis of the mating-type inheritance. However, this procedure has disadvantages in the case of polar ciliates because their generation times are at least four-fold those of temperate water ciliates and the so-called period of sexual immaturity of their life cycle (during which cells are unable to conjugate) can extend over several months (18). Therefore, to unequivocally identify homo-and heterotypic pairs as well as to distinguish between heterotypic pairs with or without cross-fertilization, we used the SSU-rRNA gene sequences (which had previously been determined in relation to the phylogenetic analysis) as cell-specific, biparentally inheritable nuclear signatures.…”

Section: Resultsmentioning

confidence: 99%

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Giuseppe

Erra

Dini

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Wild-type strains of the protozoan ciliate Euplotes collected from different locations on the coasts of Antarctica, Tierra del Fuego and the Arctic were taxonomically identified as the morpho-species Euplotes nobilii, based on morphometric and phylogenetic analyses. Subsequent studies of their sexual interactions revealed that mating combinations of Antarctic and Arctic strains form stable pairs of conjugant cells. These conjugant pairs were isolated and shown to complete mutual gene exchange and cross-fertilization. The biological significance of this finding was further substantiated by demonstrating that close homology exists among the threedimensional structures determined by NMR of the water-borne signaling pheromones that are constitutively secreted into the extracellular space by these interbreeding strains, in which these molecules trigger the switch between the growth stage and the sexual stage of the life cycle. The fact that Antarctic and Arctic E. nobilii populations share the same gene pool and belong to the same biological species provides new support to the biogeographic model of global distribution of eukaryotic microorganisms, which had so far been based exclusively on studies of morphological and phylogenetic taxonomy.ciliate mating types and sexual interactions | microbial ecology | NMR structures | polar biology | signaling by water-borne pheromones

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Section: Resultsmentioning

confidence: 99%

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Giuseppe

Erra

Dini

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…Cell cultures E. focardii cultures of the strains TN1 and TN15, and of their offspring, were used (Valbonesi and Luporini, 1993); they represent type-species material chosen from among a number of wild-type strains isolated from sediment and seawater samples collected in Antarctica (Terranova Bay coastal waters). They were cultivated in a cold room at 4 -C, using the green alga Dunaliella tertiolecta as food.…”

Section: Methodsmentioning

confidence: 99%

Ribosomal cold-adaptation: Characterization of the genes encoding the acidic ribosomal P0 and P2 proteins from the Antarctic ciliate Euplotes focardii

Pucciarelli

Marziale

Giuseppe

et al. 2005

Gene

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“…suggesting that this enzyme system is under a strainspecific genetic control. In support of this assumption there is the unusual asymmetric mating process exploited by E. focardii (Valbonesi & Luporini, 1993); in this process, only one member of a mating pair survives and it apparently preserves its genome separated from that of the partner.…”

Section: Resultsmentioning

confidence: 76%

Isozyme characterization of three Antarctic species of the hypotrich ciliateEuplotes

Valbonesi

Luporini

1993

Bolletino di zoologia

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Wild strains of Euplotes euryhalinus, E. focardii, and E. nobilii, three Antarctic species originally described on morphological grounds, were analyzed for five enzyme systems (i.e., amylases, acid phosphatases, tetrazolium oxydases, malic dehydrogenases, and malic enzyme) of proven diagnostic value for the systematics of Euplotes species. The electrophoretic patterns were all effective for discriminating strains of one species from those of another; in particular those of amylases, acid phospatases, and tetrazolium oxidases showed sharp inter-species differences and no appreciable intraspecies variations. These results provided further evidence of the species status of Euplotes euryhalinus, E. focardii, and E. nobilii.

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Biology of Euplotes focardii, an Antarctic ciliate

Cited by 36 publications

References 8 publications

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Antarctic and Arctic populations of the ciliate Euplotes nobilii show common pheromone-mediated cell-cell signaling and cross-mating

Ribosomal cold-adaptation: Characterization of the genes encoding the acidic ribosomal P0 and P2 proteins from the Antarctic ciliate Euplotes focardii

Isozyme characterization of three Antarctic species of the hypotrich ciliateEuplotes

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