Docosahexaenoic acid promotes photoreceptor differentiation without altering Crx expression

PURPOSE: The precise molecular cues required for photoreceptor development are still unknown. Pax6 and Crx are essential during early retinal development and for photoreceptor differentiation, respectively. The lipid molecule docosahexaenoic acid (DHA) has also been shown to promote photoreceptor differentiation. Pax6 expression during the early steps in photoreceptor development and whether the mutual contribution of Crx and DHA enhances photoreceptor differentiation were investigated. METHODS: Neuroblast proliferation, Crx, and Pax6 expression were investigated in rat retinas in vivo and in neuronal cultures with or without DHA. BrdU incorporation, nestin and opsin expression, apical differentiation, and axonal outgrowth were determined by phase microscopy and immunochemistry. RESULTS: Pax6 expression occurred in all proliferating retinal neuroblasts in vivo; however, after their last mitotic division, photoreceptors stopped expressing Pax6 and started expressing Crx. In vitro, photoreceptor progenitors also showed a switch from Pax6 to Crx expression immediately after they exited the cell cycle and started differentiation. In contrast, those progenitors differentiating into amacrine neurons continued expressing Pax6 and did not express Crx. Most postmitotic photoreceptors expressing Crx showed little axon development and few of them expressed opsin. The addition of DHA dramatically increased differentiation in Crx-positive photoreceptors, enhancing opsin expression, apical differentiation, and axonal outgrowth, without affecting Crx expression. CONCLUSIONS: The results suggest that Pax6 and Crx expression are mutually exclusive during photoreceptor differentiation. Onset of Crx expression may provide a permissive stage that is essential to initiate photoreceptor differentiation, but additional support of DHA, among other environmental signals, is necessary to accomplish further differentiation.Fil: Garelli, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Rotstein, Nora Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Politi, Luis Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

Nesting habitat of the Tucuman Parrot Amazona tucumana in an old-growth cloud-forest of Argentina

Tucuman Parrot Amazona tucumana breeds in the cloud-forest of south-eastern Bolivia and north-western Argentina (or Southern Yungas forest). We studied the nesting requirements of the Tucuman Parrot and assessed cavity availability, reuse, and spatial pattern of nests in El Rey National Park-one of the last mature, undisturbed areas of the Southern Yungas forest. We recorded 44 nesting attempts in seven tree species, with most nests (95%) being located in live canopy trees > 60 cm DBH. Most parrot nest-cavities occurred in Blepharocalix salicifolius (60%) and cavities in this species were selected significantly more than expected based on availability. Nests were shallower and higher than nests of other Amazona species. For all years combined, mean nest density of Tucuman Parrot was 0.24 ± 0.04 nest ha-1 and the distance to the nearest active nest was significantly greater than the distance between all trees used as nests. Nesting pairs of Tucuman Parrot were separated by 144.1 ± 152.8 m, while potential nest-trees were 66.0 ± 55.4 m apart. Density of suitable cavities for nesting was 4.6 cavities ha-1. Approximately 16 suitable cavities were available for each breeding pair (0.24 breeding pair ha-1 and four suitable cavities ha-1) and 5% of the suitable cavities available were occupied, suggesting that suitable cavities are not a limiting resource. However, due to the territorial behaviour of breeding pairs, some of these cavities are unavailable to other breeding pairs. The spatial requirements of Tucuman Parrot for nesting could limit management actions intended to increase the density of nesting pairs.Fil: Rivera, Luis. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Cátedra de Desarrollo Sustentable y Biodiversidad; ArgentinaFil: Politi, Natalia. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Cátedra de Desarrollo Sustentable y Biodiversidad; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bucher, Enrique Hugo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Zoología Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effect of GDNF on neuroblast proliferation and photoreceptor survival: additive protection with docosahexaenoic acid

Purpose. In a previous study, it was reported that docosahexaenoic acid (DHA) is essential to postpone apoptosis and to promote differentiation of rat retina photoreceptors in vitro. In the current study, the protective effects of GDNF on photoreceptor cells during development in vitro and its action when combined with DHA were investigated. Methods. Rat retina neuronal cultures were incubated in a chemically defined medium, either without photoreceptor survival factors or supplemented with GDNF, DHA, or GDNF plus DHA. Evolution of survival, apoptosis, opsin expression, mitochondrial functioning, and cell proliferation were investigated at different times of development in vitro. Results. Incubation with GDNF selectively increased the number of surviving photoreceptors, reduced their apoptosis, and augmented opsin expression. Proliferative cell nuclei antigen (PCNA) determination and addition of [3H]-thymidine or bromodeoxyuridine showed that GDNF promoted neuroblast proliferation during the first hours of development in vitro. The combined addition of GDNF and DHA enhanced opsin expression and photoreceptor survival in an additive manner. The advance of photoreceptor apoptosis in cultures without trophic factors correlated with an increased impairment in mitochondrial functionality. Addition of GDNF and DHA significantly diminished the loss of mitochondrial activity. Conclusions. These results show that GDNF stimulated the cell cycle progression, leading to neuroblast proliferation at early stages of development, and delayed the onset of apoptosis later on, improving differentiation and acting as a trophic factor for photoreceptors. The combination of GDNF with DHA had an additive effect both on photoreceptor survival and on opsin expression. Preservation of mitochondrial function may be involved in the antiapoptotic effect of both factors.Instituto Multidisciplinario de Biología Celula

Effect of GDNF on neuroblast proliferation and photoreceptor survival: additive protection with docosahexaenoic acid

Purpose. In a previous study, it was reported that docosahexaenoic acid (DHA) is essential to postpone apoptosis and to promote differentiation of rat retina photoreceptors in vitro. In the current study, the protective effects of GDNF on photoreceptor cells during development in vitro and its action when combined with DHA were investigated. Methods. Rat retina neuronal cultures were incubated in a chemically defined medium, either without photoreceptor survival factors or supplemented with GDNF, DHA, or GDNF plus DHA. Evolution of survival, apoptosis, opsin expression, mitochondrial functioning, and cell proliferation were investigated at different times of development in vitro. Results. Incubation with GDNF selectively increased the number of surviving photoreceptors, reduced their apoptosis, and augmented opsin expression. Proliferative cell nuclei antigen (PCNA) determination and addition of [3H]-thymidine or bromodeoxyuridine showed that GDNF promoted neuroblast proliferation during the first hours of development in vitro. The combined addition of GDNF and DHA enhanced opsin expression and photoreceptor survival in an additive manner. The advance of photoreceptor apoptosis in cultures without trophic factors correlated with an increased impairment in mitochondrial functionality. Addition of GDNF and DHA significantly diminished the loss of mitochondrial activity. Conclusions. These results show that GDNF stimulated the cell cycle progression, leading to neuroblast proliferation at early stages of development, and delayed the onset of apoptosis later on, improving differentiation and acting as a trophic factor for photoreceptors. The combination of GDNF with DHA had an additive effect both on photoreceptor survival and on opsin expression. Preservation of mitochondrial function may be involved in the antiapoptotic effect of both factors.Instituto Multidisciplinario de Biología Celula

Effect of GDNF on neuroblast proliferation and photoreceptor survival: additive protection with docosahexaenoic acid

Purpose. In a previous study, it was reported that docosahexaenoic acid (DHA) is essential to postpone apoptosis and to promote differentiation of rat retina photoreceptors in vitro. In the current study, the protective effects of GDNF on photoreceptor cells during development in vitro and its action when combined with DHA were investigated. Methods. Rat retina neuronal cultures were incubated in a chemically defined medium, either without photoreceptor survival factors or supplemented with GDNF, DHA, or GDNF plus DHA. Evolution of survival, apoptosis, opsin expression, mitochondrial functioning, and cell proliferation were investigated at different times of development in vitro. Results. Incubation with GDNF selectively increased the number of surviving photoreceptors, reduced their apoptosis, and augmented opsin expression. Proliferative cell nuclei antigen (PCNA) determination and addition of [3H]-thymidine or bromodeoxyuridine showed that GDNF promoted neuroblast proliferation during the first hours of development in vitro. The combined addition of GDNF and DHA enhanced opsin expression and photoreceptor survival in an additive manner. The advance of photoreceptor apoptosis in cultures without trophic factors correlated with an increased impairment in mitochondrial functionality. Addition of GDNF and DHA significantly diminished the loss of mitochondrial activity. Conclusions. These results show that GDNF stimulated the cell cycle progression, leading to neuroblast proliferation at early stages of development, and delayed the onset of apoptosis later on, improving differentiation and acting as a trophic factor for photoreceptors. The combination of GDNF with DHA had an additive effect both on photoreceptor survival and on opsin expression. Preservation of mitochondrial function may be involved in the antiapoptotic effect of both factors.Instituto Multidisciplinario de Biología Celula

Retinoic acid promotes apoptosis and differentiation in photoreceptors by activating the p38 MAP kinase pathway

Purpose Retinoic acid (RA) has a critical role during development of the retina, controlling cell fate and differentiation. We here investigated RA effects on photoreceptor differentiation and apoptosis and the intracellular pathways involved in these effects. Methods Rat retinal neuronal cultures were supplemented with RA and with or without docosahexaenoic acid (DHA), a photoreceptor trophic factor. Photoreceptor apoptosis and differentiation were evaluated at different times of development. The effect of the pan caspase inhibitor Z-VAD-FMK on apoptosis and differentiation was determined. RA activation of p38 MAP kinase was determined by evaluating phosphorylated (P)-p38 levels in cultures with or without RA and the effect of pre-treatment with SB203580, a p38 specific inhibitor. Results RA addition at day 0, when cells were still proliferating, selectively increased apoptosis in photoreceptors, whereas addition at day 2 no longer caused cell death. DHA and Z-VAD-FMK prevented this early apoptosis. RA stimulated opsin and peripherin expression and neurite outgrowth regardless of time of development. RA addition rapidly increased P-p38 levels, whereas p38 inhibition decreased RA-induced differentiation and apoptosis, without affecting neurite outgrowth. Conclusions Our results show that RA stimulated differentiation and induced an early apoptosis in photoreceptors, which were rescued by DHA addition. Noteworthy, activation of the p38 intracellular pathway was required for RA effects on both differentiation and apoptosis. This suggests that RA induction of differentiation during early development must be counterbalanced by survival factors, such as DHA, to prevent photoreceptor death and this interplay might help to establish the final number of photoreceptors.Fil: de Genaro, Pablo Adrian. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.bioquimicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; ArgentinaFil: Simón, Maria Victoria. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.bioquimicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; ArgentinaFil: Rotstein, Nora Patricia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.bioquimicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; ArgentinaFil: Politi, Luis Enrique. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.bioquimicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; Argentin

Ecology and conservation of the Alder Amazon (Amazona tucumana)

El Loro Alisero (Amazona tucumana) es endémico de las selvas subtropicales de montaña del noroeste de Argentina y sur de Bolivia (Yungas Australes). En este trabajo se recopila información publicada y novedosa sobre aspectos ecológicos y de conservación del Loro Alisero. Se registró al Loro Alisero consumiendo semillas, frutos y flores de 18 especies nativas y 5 exóticas. Se identificaron nidos en 10 especies de árboles distribuidos entre los 1470-2200 msnm y se encontró una alta variabilidad en la densidad de nidos. Se detectaron seis dormideros que albergan la totalidad o una buena parte de las poblaciones de un área, por lo que una buena estrategia de monitoreo de sus poblaciones sería realizar conteos en ellos todos los años, de manera de tener una estimación de las tendencias poblacionales a largo plazo. Fueron registrados 7650 individuos en 26 sitios en Argentina y Bolivia. Es probable que el tamaño poblacional actual sea menor que el anterior a la década de 1980, cuando las capturas para el comercio internacional de mascotas alcanzó su máximo. Los resultados obtenidos sugieren que el Loro Alisero cumple con los criterios para ser categorizado como Vulnerable según la Lista Roja de la UICN. Dado sus requerimientos específicos de reproducción y alimentación es necesario elaborar pautas de manejo forestal y crear áreas protegidas que aseguren la conservación de la especie.The Alder Amazon (Amazona tucumana) is an endemic parrot from the subtropical montane forests of northwestern Argentina and southern Bolivia (Austral Yungas). We collected published and novel information on the species biology, ecology, and conservation. We recorded Alder Amazon feeding on seeds, fruits, and flowers of 18 native and 5 alien species. We identified nests in 10 tree species along an elevation gradient between 1470-2200 masl and we found a high variability in nest density. We found six roosts harbouring whole or most of the populations of an area; therefore, to monitor population trends it would be a good strategy to conduct roost counts yearly. We recorded 7650 individuals in 26 sites in Argentina and Bolivia. The current population size is probably lower than the level before the 1980's when captures for the international pet trade attained a maximum. Our data suggest that Alder Amazon meets the criteria to be categorized as Vulnerable under the Red List of IUCN. Due to the specific reproductive and feeding requirements it is necessary to delineate forest management guidelines and create protected areas that can assure the species conservation.Fil: Rivera, Luis Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Cátedra de Desarrollo Sustentable y Biodiversidad; Argentina. Fundación para la Conservación y Estudio de la Biodiversidad; ArgentinaFil: Politi, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Cátedra de Desarrollo Sustentable y Biodiversidad; Argentina. Fundación para la Conservación y Estudio de la Biodiversidad; ArgentinaFil: Bucher, Enrique Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Zoología Aplicada; Argentin

Retina stem cells, hopes and obstacles

Retinal degeneration is a major contributor to visual dysfunction worldwide. Although it comprises several eye diseases, loss of retinal pigment epithelial (RPE) and photoreceptor cells are the major contributors to their pathogenesis. Early therapies included diverse treatments, such as provision of anti-vascular endothelial growth factor and many survival and trophic factors that, in some cases, slow down the progression of the degeneration, but do not effectively prevent it. The finding of stem cells (SC) in the eye has led to the proposal of cell replacement strategies for retina degeneration. Therapies using different types of SC, such as retinal progenitor cells (RPCs), embryonic SC, pluripotent SCs (PSCs), induced PSCs (iPSCs), and mesenchymal stromal cells, capable of self-renewal and of differentiating into multiple cell types, have gained ample support. Numerous preclinical studies have assessed transplantation of SC in animal models, with encouraging results. The aim of this work is to revise the different preclinical and clinical approaches, analyzing the SC type used, their efficacy, safety, cell attachment and integration, absence of tumor formation and immunorejection, in order to establish which were the most relevant and successful. In addition, we examine the questions and concerns still open in the field. The data demonstrate the existence of two main approaches, aimed at replacing either RPE cells or photoreceptors. Emerging evidence suggests that RPCs and iPSC are the best candidates, presenting no ethical concerns and a low risk of immunorejection. Clinical trials have already supported the safety and efficacy of SC treatments. Serious concerns are pending, such as the risk of tumor formation, lack of attachment or integration of transplanted cells into host retinas, immunorejection, cell death, and also ethical. However, the amazing progress in the field in the last few years makes it possible to envisage safe and effective treatments to restore vision loss in a near future.Fil: German, Olga Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Vallese Maurizi, Harmonie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Soto, Tamara Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Rotstein, Nora Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Politi, Luis Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

A Defective Crosstalk Between Neurons and Müller Glial Cells in the rd1 Retina Impairs the Regenerative Potential of Glial Stem Cells

Müller glial cells (MGC) are stem cells in the retina. Although their regenerative capacity is very low in mammals, the use of MGC as stem cells to regenerate photoreceptors (PHRs) during retina degenerations, such as in retinitis pigmentosa, is being intensely studied. Changes affecting PHRs in diseased retinas have been thoroughly investigated; however, whether MGC are also affected is still unclear. We here investigated whether MGC in retinal degeneration 1 (rd1) mouse, an animal model of retinitis pigmentosa, have impaired stem cell properties or structure. rd1 MGC showed an altered morphology, both in culture and in the whole retina. Using mixed neuron-glial cultures obtained from newborn mice retinas, we determined that proliferation was significantly lower in rd1 than in wild type (wt) MGC. Levels of stem cell markers, such as Nestin and Sox2, were also markedly reduced in rd1 MGC compared to wt MGC in neuron-glial cultures and in retina cryosections, even before the onset of PHR degeneration. We then investigated whether neuron-glial crosstalk was involved in these changes. Noteworthy, Nestin expression was restored in rd1 MGC in co-culture with wt neurons. Conversely, Nestin expression decreased in wt MGC in co-culture with rd1 neurons, as occurred in rd1 MGC in rd1 neuron-glial mixed cultures. These results imply that MGC proliferation and stem cell markers are reduced in rd1 retinas and might be restored by their interaction with "healthy" PHRs, suggesting that alterations in rd1 PHRs lead to a disruption in neuron-glial crosstalk affecting the regenerative potential of MGC.Fil: Volonté, Yanel Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Vallese Maurizi, Harmonie Agostina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Dibo, Marcos Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Ayala Peña, Victoria Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Garelli, Andres. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Zanetti, Samanta Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Turpaud Barrera, Axel Hector Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Craft, Cheryl Mae. University Of Southern California; Estados UnidosFil: Rotstein, Nora Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Politi, Luis Enrique. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: German, Olga Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

EVALITA Evaluation of NLP and Speech Tools for Italian - December 17th, 2020

Welcome to EVALITA 2020! EVALITA is the evaluation campaign of Natural Language Processing and Speech Tools for Italian. EVALITA is an initiative of the Italian Association for Computational Linguistics (AILC, http://www.ai-lc.it) and it is endorsed by the Italian Association for Artificial Intelligence (AIxIA, http://www.aixia.it) and the Italian Association for Speech Sciences (AISV, http://www.aisv.it)