Molecular characterization of carotenogenic yeasts from aquatic environments in Patagonia, Argentina |
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Authors: | Diego Libkind Silvia Brizzio Alejandra Ruffini Mário Gadanho Maria van Broock José Paulo Sampaio |
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Institution: | Universidad Nacional del Comahue, Centro Regional Universitario Bariloche (CRUB)--CONICET (Consejo Nacional de Investigaciones Científicas y Tecnológicas), Bariloche, Río Negro, Argentina. libkind@crub.uncoma.edu.ar |
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Abstract: | Fifteen aquatic environments (lakes, lagoons and rivers) of glacial origin in the northern Andean Patagonia (Argentina) were
surveyed for the occurrence of red yeasts. Subsurface water samples were filtered and used for colony counting and yeast isolation.
A preliminary quantitative analysis indicated that total yeast counts ranged between 0 and 250 cells l−1. A polyphasic approach including physiological and molecular methods was used for the identification of 64 carotenogenic
yeast strains. The molecular characterisation of the isolates was based on the mini/microsatellite-primed PCR technique (MSP-PCR)
employing the (GTG)5 and the M13 primers. Comparison of representative fingerprints of each group with those of the type strains of pigmented
yeasts allowed the expeditious identification of 87.5% isolates. The sequence analysis of the D1/D2 domains of the 26S rDNA
was employed to confirm identifications and in the characterization of the unidentified MSP-PCR groups. Teleomorphic yeast
species were detected by performing sexual compatibility assays. The isolates corresponded to 6 genera and 15 yeast species,
including four new yeast species of the genera Cryptococcus (1), Rhodotorula (1) and Sporobolomyces (2). Rhodotorula mucilaginosa was found in the majority of the samples and represented ca. 50% of the total number of isolates. However, this yeast was
not detected in aquatic environments with very low anthropic influence. Other frequent yeast isolates were teleomorphic yeast
species of Rhodosporidium babjevae, R. kratochvilovae and Sporidiobolus salmonicolor. This study represents the first report on red yeast occurrence and biodiversity in northwestern Patagonia.
This revised version was published online in June 2006 with corrections to the Cover Date. |
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Keywords: | Aquatic environments Carotenogenic yeasts MSP-PCR fingerprinting Patagonia 26S rDNA sequence |
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