National University of Comahue

About: National University of Comahue is a education organization based out in Neuquén, Argentina. It is known for research contribution in the topics: Population & Species richness. The organization has 2242 authors who have published 4498 publications receiving 87157 citations. The organization is also known as: UNCOMA & UNCo.

The use of killer biotyping in an ecological survey of yeast in an old patagonian winery

Abstract: An ecological study of Saccharomyces cerevisiae strains in spontaneous alcoholic fermentation has been made in the same winery on two consecutive years (1993 and 1994) with Merlot type musts, and with Malbec type must on a third year (1998). Saccharomyces cerevisiae strains associated with winery surfaces were also analysed. Differential killer sensitivity patterns related to a killer reference panel of 10 killer yeasts belonging to nine species of four genera were used as a quick and simple procedure to discriminate between indigenous S. cerevisiae isolates at the strain level. Although a great diversity of wild strains was observed, two main indigenous S. cerevisiae strains, designated as S. cerevisiae 9 and S. cerevisiae 13, took over the Merlot type fermentation in both years. These strains also appeared in Malbec must fermentation during the year 1998 and they were again found on the winery surface the next year. These results show that some few and stable indigenous S. cerevisiae strains remained in the environmental winery over the considered period of time (1993–1999) and they represent an additional evidence of the taking over of musts by local strains of S. cerevisiae.

Biological weighting function for the mortality of Boeckella gracilipes (Copepoda, Crustacea) derived from experiments with natural solar radiation.

Abstract: We performed in situ experiments during the austral summer of 1998 to quantify the mortality of the freshwater copepod Boeckella gracilipes as a function of the UV dose. The copepods were exposed to solar radiation at the water-surface for ∼24–34 h. Long-pass cut-off filters (Schott) were used in the exposure experiments. UV radiation and PAR were measured with an IL-1700 (International Light Inc.) and a PUV-500 radiometer (Biospherical Instruments Inc.). A biological weighting function for UV-induced mortality was calculated by fitting a model based on a logistic curve. Our results show that UV damage in this species is strongly wavelength- and dose-dependent. B. gracilipes was highly vulnerable to both UV-B (290–320 nm) and UV-A radiation (< 360 nm). The shape of the BWF obtained for B. gracilipes resembles more closely the action spectra (AS)† for UV-induced erythema, than the AS for naked DNA.

Studies on the heterogeneity of the carotenogenic yeast Rhodotorula mucilaginosa from Patagonia, Argentina.

Abstract: The yeast species Rhodotorula mucilaginosa is considered to be ubiquitous due to its world-wide distribution in terrestrial, freshwater and marine habitats, and to its ability to colonize a large variety of substrates. In this paper we assess the phenotypic and genetic variability of environmental isolates of R. mucilaginosa collected from natural and artificial environments in Patagonia, Argentina. A total of 97 strains were studied and sorted into three groups based on MSP-PCR fingerprinting results: A, which comprised 90% of the strains, including the type strain; and B and C which included 2 and 8% of the strains, respectively. The D1D2 sequencing did not differentiate any of the 3 groups, while ITS sequencing validated the existence of group C. This group was composed of Patagonian isolates of diverse origin. DNA-DNA reassociation studies confirmed the existence of significant genetic differences between group C and the type strain. In this study, which is the first on the intraspecific variability of a large set of R. mucilaginosa isolates, a considerable phenotypic and genetic heterogeneity was observed, however such differences were not enough to refute co-specificity. The study of Patagonian isolates allowed the detection of a genetically distinct group of R. mucilaginosa strains. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

(Un)Coupled thrust belt-foreland deformation in the northern Patagonian Andes: new insights from the Esquel-Gastre sector (41°30’–43° S)

Abstract: The Patagonian Andes represent a unique natural laboratory to study surface deformation in relation to deep slab dynamics. In the sector comprised between latitudes 41°30’ and 43°S, new apatite (U-Th)/He ages indicate a markedly different unroofing pattern between the ‘broken foreland’ area (characterized by Late Cretaceous to Paleogene exhumation) and the adjacent Andean sector to the west, which is dominated by Miocene-Pliocene exhumation. These unroofing stages can be confidently ascribed to inversion tectonics involving reverse fault-related uplift and concomitant erosion. Late Cretaceous-Paleogene shortening and exhumation are well known to have affected also the thrust belt sector of the study area during a prolonged stage of flat-slab subduction. Therefore, the different ages of near-surface unroofing documented in this study suggest coupling of the deformation between the thrust belt and its foreland during periods of flat-slab subduction (e.g. during Late Cretaceous-Paleogene times), and dominant uncoupling during periods of steep-slab subduction and rollback, even when these are associated with high convergence rates (i.e. > 4 cm/year), as those documented in Miocene times for the Patagonian Andes.