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.

Predation on snakes of Argentina: Effects of coloration and ring pattern on coral and false coral snakes

Abstract: The occurrence of coral snake coloration among unrelated venomous and non‐venomous snake species has often been explained in terms of warning coloration and mimicry. In Argentina, no field tests have been conducted to confirm this mimetic association between one venomous coral species (Micrurus phyrrocryptus, Elapidae) and two non‐venomous snake species with a similar color pattern (Lystrophis pulcher and Oxyrhopus rhombifer, Colubridae). The aims of this work were to test for the possible aposematic or cryptic function of the ring pattern and coloration of coral snakes and false coral snakes from central Argentina, and to analyse whether the pattern is effective throughout the year. Predation on snakes was estimated by using non‐toxic plasticine replicas of ringed venomous and non‐venomous snakes and unbanded green snakes placed along transects in their natural habitat during the dry and rainy season. Ringed color pattern was attacked by predators despite the background color. One of the replica types wa...

Cholinesterase activities in developing amphibian embryos following exposure to the insecticides dieldrin and malathion.

Abstract: The exposure of toad (Bufo arenarum) embryos to dieldrin2 and malathion3 produced an inhibition of acetyl (AChE) and butyryl (ChE) cholinesterase. Dieldrin treatment induced hyperactivity in the swimming larvae; malathion showed no detectable behavioral effects.In vivo adsorption of dieldrin by the oocyte produced delayed toxicity in the embryo.In vitro inhibition of AChE was not significant; 47.3 mg/L of malathion in the medium interrupted embryogenesis, but 0.47 mg/L permitted the embryo to complete their development without the appearance of any observable malformations.

Population structure, distribution and harvesting of southern geoduck, Panopea abbreviata, in San Matías Gulf (Patagonia, Argentina)

Abstract: Southern geoduck is the most long-lived bivalve species exploited in the South Atlantic and is harvested by divers in San Matias Gulf. Except preliminary data on growth and a gametogenic cycle study, there is no basic information that can be used to manage this resource in terms of population structure, harvesting, mortality and inter-population comparisons of growth. Our aim was to analyze the spatial distribution from survey data, population structure, growth and mortality of several beds along a latitudinal gradient based on age determination from thin sections of valves. We also described the spatial allocation of the fleet’s fishing effort, and its sources of variability from data collected on board. Three geoduck beds were located and sampled along the coast: El Sotano, Punta Colorada and Puerto Lobos. Geoduck ages ranged between 2 and 86 years old. Growth patterns showed significant differences in the asymptotic size between El Sotano (109.4 mm) and Puerto Lobos (98.06 mm). The maximum age decreased from north to south. Natural mortality was estimated for each bed according to a catch curve ( M = 0.105 – 0.177 yr -1 ), with a method based on mean age ( M = 0.212 – 0.233 yr -1 ) and a method based on maximum longevity recorded ( M = 0.062 – 0.13 yr -1 ). Population features were integrated into the harvest analysis to generate a preliminary management proposal that includes subdivision of the coastal zone, limited entry, harvest rate and individual vessel quotas.

ENSO as a forewarning tool of regional fire occurrence in northern Patagonia, Argentina

Abstract: Composite series of ENSO indices recorded over 36 months preceding major fire years in four National Parks in northern Patagonia were compared with series of these indices for individual years over the period 1950–1996 by means of an additive temporal phase coherence index. Logistic regressions of the dichotomous variable high vs low regional fire occurrence against the coherence index gained highest significant classificatory power using an index based on SST anomaly data between January of year –3 to August of year –1. Thus, warnings of extreme fire seasons could be declared as early as 3 months before the full fire season starts (i.e. early September). A regional fire season readiness index is proposed based on the periodicity of the Southern Oscillation, strong links with climate at particular regions of the globe, and empirically derived climatic controls on fine fuel buildup and coarse fuel desiccation. This long-range alerting tool could help decision-makers prepare preventative measures to mitigate the effects of large, high intensity wildfire seasons. However, it should be used with caution given that differences in timing in the onset of ENSO events and instability in teleconnection patterns could change climatic sequences, differentially affecting fire susceptibility.

UVB Photoprotective Role of Mycosporines in Yeast: Photostability and Antioxidant Activity of Mycosporine-Glutaminol-Glucoside

Abstract: Several yeast species are able to synthesize and accumulate UV-radiation-absorbing mycosporine metabolites that are of unclear physiological function. In this work we analyzed the relationship between mycosporine-glutaminol glucoside (MGG) production, cell survival after UVB irradiation, and formation of cyclobutane pyrimidine dimers (CPDs). We also assessed the photostability and singlet oxygen quenching activity of MGG. A set of nine isolates of the basidiomycetous yeast Cryptococcus steppossus cultured in both dark and light conditions was used for the studies. Survival of the UVB-irradiated isolates and MGG concentration had a linear relationship when the concentration was over 2.5 mg g−1. CPD accumulation and MGG accumulation were inversely related. MGG in aqueous solution was photostable with a photodecomposition quantum yield of 1.16 × 10−5. MGG quenching of singlet oxygen was also observed, and the rate constant for the process in D2O was 5.9 × 107 M−1 s−1. Our results support the idea th...