Centro Científico Tecnológico Salta - Jujuy

Lignocellulosic fungi are highly versatile organisms with valuable applications in bioremediation processes, including the biodegradation of agro-industrial effluents. In this work, the use of a native strain of the white-rot fungus, Pycnoporus aff. sanguineus, in the bioremediation of the sugar industry waste called vinasse was studied, originating from the San Martín del Tabacal Sugar Mill, located in the north of the Salta province, Argentina. We studied, under controlled laboratory conditions, the bioremediation process of three concentrations of vinasse (5, 10, and 25% in distilled water) with a native isolated strain. The results showed biomass growth at all three tested concentrations, with a maximum at the highest vinasse concentration (25%), while the percentages of color and Chemical Oxygen Demand (COD) removal indicated that the most efficient treatment was with 10% vinasse. The results obtained are promising for the treatment of effluents from the sugar industry using white-rot fungi, considering the valuable subproducts of Pycnoporus spp. biomass.

Lithraea molleoides -Anacardiaceae- and Schinopsis haenkeana -Anacardiaceae- are native tree species of great importance in the Chaco Serrano, a region poorly studied in relation to the possible effects that climate change (CC) could have on its extension. Species distribution models are one of the most used tools for tree species conservation in the context of the global climate change. These type of models allow to study the potential distribution of species under current and hypothetical future conditions and the effectiveness of protected areas in representing species. Using modeling techniques we studied the potential distribution of both species for current and hypothetical future climatic conditions (period 2041-2060). Also, we used geographic information systems to determine the potential protected area. The models had a high concordance with the known distribution for both species and showed a potential distribution area of 1124737 km2 for L. molleoides, and 158491 km2 for S. haenkeana. Under climate change scenarios, L. molleoides showed a reduction of 18% in the potential distribution, while S. haenkeana showed an increase of 14% in the potential distribution. For both species, the representation in protected areas of categories I to IV of the International Union for Conservation of Nature was less than 10% of the potential distribution area. Thus, we suggest increasing the protected area considering the potential distribution under future climatic warming scenarios, and to implement conservation strategies integrating the sustainable use of the forest.

The maintenance of the secretory response requires a continuous replenishment of releasable vesicles. It was proposed that the immediately releasable pool (IRP) is important in chromaffin cell secretion during action potentials applied at basal physiological frequencies, because of the proximity of IRP vesicles to voltage-dependent Ca2+ channels. However, previous reports showed that IRP replenishment after depletion is too slow to manage such a situation. In this work, we used patch-clamp measurements of membrane capacitance, confocal imaging of F-actin distribution, and cytosolic Ca2+ measurements with Fura-2 to re-analyze this problem in primary cultures of mouse chromaffin cells. We provide evidence that IRP replenishment has one slow (time constant between 5 and 10s) and one rapid component (time constant between 0.5 and 1.5s) linked to a dynamin-dependent fast endocytosis. Both, the fast endocytosis and the rapid replenishment component were eliminated when 500nM Ca2+ was added to the internal solution during patch-clamp experiments, but they became dominant and accelerated when the cytosolic Ca2+ buffer capacity was increased. In addition, both rapid replenishment and fast endocytosis were retarded when cortical F-actin cytoskeleton was disrupted with cytochalasin D. Finally, in permeabilized chromaffin cells stained with rhodamine-phalloidin, the cortical F-actin density was reduced when the Ca2+ concentration was increased in a range of 10-1000nM. We conclude that low cytosolic Ca2+ concentrations, which favor cortical F-actin stabilization, allow the activation of a fast endocytosis mechanism linked to a rapid replenishment component of IRP.

Precios y crisis en una economa rioplatense.

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Transitional spaces (TS) are characterized by possession of high gradients of luminances between inside and out, which places a great demand on the users’ visual system's function. A satisfactory descriptive indicator of this kind of situation could be a ‘modelling factor’ (MF), defined from cylindrical illuminance and horizontal illuminance measures. It would provide information on the depth and dimensionality of objects present in the scene, also taking into account a region's overabundance of daylight. A public building was selected as a case study, and solar light behaviour, including its interaction with the space, was monitored. Measurements were taken during an entire year at the start of each season (2008) under clear skies, at the beginning and at the end of each working day. Another measurement was taken in winter (2009) under overcast skies at 13:00, so as to obtain a comparative parameter. It was found that unfavourable conditions were produced in all seasons for about 2 hours, except at 09:15 in winter. All the data collected in the control situation were within the optimum modelling range, with values ranging between 0.3 and 0.4. The MF allows the integration of most relevant factors intervening in TS and emerges as a good descriptor for TS.