Reseña de "Tercera persona. Política de la vida y filosofía de lo impersonal"

Reseña de "Tercera persona. Política de la vida y filosofía de lo impersonal", de Roberto Espósito, Amorrortu Editores, Buenos Aires, 2007, 224 pp

Notes on the natural history and distribution of the Ochre-flanked Eugralla (Eugralla paradoxa) in Argentina.

El Churrín Grande (Eugralla paradoxa) abarca en Argentina una estrecha franja de aproximadamente 300 km de largo y 30 km de ancho sobre la frontera con Chile, en el sudoeste de las provincias de Neuquén y Río Negro, y en el noroeste de Chubut. Aunque fue considerado restringido a la selva valdiviana está presente en localidades alejadas de los sectores más húmedos del bosque, aparentemente más relacionado con arbustales muy cerrados cercanos a pequeños arroyos (cualquiera sea su composición florística) y pasos cordilleranos inferiores a los 1000 m s.n.m. que la conecten con núcleos de dispersión de la región valdiviana chilena, que con las precipitaciones y el bosque higrófilo climáxico argentinos. Considerado hasta ahora raro en Argentina, el Churrín Grande llega a ser común en algunos sitios de los Parques Nacionales Lago Puelo y Nahuel Huapi y áreas cercanas; su aparente expansión geográfica en Argentina pareciera deberse a la aparición de nuevos hábitats secundarios como los densos arbustales de rosa mosqueta (Rosa rubiginosa). Describimos e ilustramos con sonogramas seis tipos de vocalizaciones: tres llamados de contacto, dos voces de proclamación y un llamado de alarma.The Ochre-flanked Eugralla (Eugralla paradoxa) is distributed in Argentina along a narrow band approximately 300 km long and 30 km wide in south-west Neuquén and Río Negro, and in north-west Chubut, against the Chilean border. Although it has been considered restricted to the Valdivian Forest, it is present in localities far from the most humid forest sectors; presumably more related with dense shrubby habitats in close proximity to small streams (irrespective of their floristic com- position) and Andean passes below 1000 m a.s.l. connected to the Chilean Valdivian Forest, than with rainfall and humid climax forests in Argentina. Up to now considered rare in Argentina, the Ochre-flanked Eugralla is common at sites in Lago Puelo and Nahuel Huapi national parks, and nearby areas. Its appar- ent geographic expansion in Argentina seems to be related to the occurrence of new secondary habitats, such as dense thickets of the exotic sweet briar (Rosa rubiginosa). We describe and illustrate with sono- grams six vocal types: three contact calls, two territorial voices, and one alarm call.Fil: Vidoz, Félix. Administración de Parques Nacionales. Parque Nacional Lago Puelo; ArgentinaFil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentin

Two new records of Polystichum (Dryopteridaceae) for the Argentine Flora

En este trabajo, dos nuevos taxones de Polystichum se registran para la flora de helechos deArgentina: P. subintegerrimum (Hook. & Arn.) R. Rodr. hallado en la región de los Bosques Patagónicos yP. platylepis Fée colectado en Misiones; hasta ahora, ambas especies eran consideradas endémicas deChile y Brasil, respectivamente. Se describen e ilustran ambas especies.In this paper, two new records for the Argentina fern-flora are reported: P. subintegerrimum (Hook. & Arn.) R. Rodr. found in the Patagonian Forests and P. platylepis Fée collected in Misiones; both have been considered endemic for Chile and Brazil, respectively. The species are described and illustrated.Fil: Morero, Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas; ArgentinaFil: Giorgis, Melisa Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Condack, Joao P. S.. Universidade Federal do Rio de Janeiro; BrasilFil: Vidoz, Félix F.. Parque Nacional Lago Puelo; ArgentinaFil: Barboza, Gloria Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas; Argentin

nifH pyrosequencing reveals the potential for location-specific soil chemistry to influence N2-fixing community dynamics

A dataset of 87 020 nifH reads and 16 782 unique nifH protein sequences obtained over 2 years from four locations across a gradient of agricultural soil types in Argentina were analysed to provide a detailed and comprehensive picture of the diversity, abundance and responses of the N2-fixing community in relation to differences in soil chemistry and agricultural practices. Phylogenetic analysis revealed an expected high proportion of Alphaproteobacteria, Betaproteobacteria and Deltaproteobacteria, mainly relatives to Bradyrhizobium and Methylosinus/Methylocystis, but a surprising paucity of Gammaproteobacteria. Analysis of variance and stepwise regression modelling suggested location and treatment-specific influences of soil type on diazotrophic community composition and organic carbon concentrations on nifH diversity. nifH gene abundance, determined by quantitative real-time polymerase chain reaction, was higher in agricultural soils than in non-agricultural soils, and was influenced by soil chemistry under intensive crop rotation but not under monoculture. At some locations, sustainable increased crop yields might be possible through the management of soil chemistry to improve the abundance and diversity of N2-fixing bacteriaFil: Collavino, Mónica Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Tripp, H. James. University of California. Department of Ocean Sciences; Estados UnidosFil: Frank, Ildiko E.. University of California. Department of Ocean Sciences; Estados UnidosFil: Vidoz, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); ArgentinaFil: Calderoli, Priscila Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Donato, Mariano Humberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Laboratorio de Sistemática y Biología Evolutiva; ArgentinaFil: Zehr, Jonathan P.. University of California. Department of Ocean Sciences; Estados UnidosFil: Aguilar, Orlando Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Biotecnología y Biología Molecular; Argentin

Increased chromosomal radiosensitivity in asymptomatic carriers of a heterozygous BRCA1 mutation

Background: Breast cancer risk increases drastically in individuals carrying a germline BRCA1 mutation. The exposure to ionizing radiation for diagnostic or therapeutic purposes of BRCA1 mutation carriers is counterintuitive, since BRCA1 is active in the DNA damage response pathway. The aim of this study was to investigate whether healthy BRCA1 mutations carriers demonstrate an increased radiosensitivity compared with healthy individuals. Methods: We defined a novel radiosensitivity indicator (RIND) based on two endpoints measured by the G2 micronucleus assay, reflecting defects in DNA repair and G2 arrest capacity after exposure to doses of 2 or 4 Gy. We investigated if a correlation between the RIND score and nonsense-mediated decay (NMD) could be established. Results: We found significantly increased radiosensitivity in the cohort of healthy BRCA1 mutation carriers compared with healthy controls. In addition, our analysis showed a significantly different distribution over the RIND scores (p = 0.034, Fisher’s exact test) for healthy BRCA1 mutation carriers compared with non-carriers: 72 % of mutation carriers showed a radiosensitive phenotype (RIND score 1–4), whereas 72 % of the healthy volunteers showed no radiosensitivity (RIND score 0). Furthermore, 28 % of BRCA1 mutation carriers had a RIND score of 3 or 4 (not observed in control subjects). The radiosensitive phenotype was similar for relatives within several families, but not for unrelated individuals carrying the same mutation. The median RIND score was higher in patients with a mutation leading to a premature termination codon (PTC) located in the central part of the gene than in patients with a germline mutation in the 5′ end of the gene. Conclusions: We show that BRCA1 mutations are associated with a radiosensitive phenotype related to a compromised DNA repair and G2 arrest capacity after exposure to either 2 or 4 Gy. Our study confirms that haploinsufficiency is the mechanism involved in radiosensitivity in patients with a PTC allele, but it suggests that further research is needed to evaluate alternative mechanisms for mutations not subjected to NMD

Internal aeration and respiration of submerged tomato hypocotyls is enhanced by ethylene‐mediated aerenchyma formation and hypertrophy

With the impending threat that climate change is imposing on all terrestrial ecosystems, plants ability to adjust to changing environments is, more than ever, a very desirable trait. Tomato (Solanum lycopersicum L.) plants display a number of responses that allow them to survive under different abiotic stresses such as flooding. We focused on understanding the mechanism that facilitates oxygen diffusion to submerged tissues and the impact it has on sustaining respiration levels. We observed that, as flooding stress progresses, stems increase their diameter and internal porosity. Ethylene triggers stem hypertrophy by inducing cell wall loosening genes, and aerenchyma formation seems to involve programmed cell death mediated by oxygen peroxide. We finally assessed whether these changes in stem morphology and anatomy are indeed effective to restore oxygen levels in submerged organs. We found that aerenchyma formation and hypertrophy not only increase oxygen diffusion towards the base of the plant but also result in an augmented respiration rate. We consider that this response is crucial to maintain adventitious root development under such conditions and, therefore, making it possible for the plant to survive when the original roots die.Fil: Mignolli, Francesco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Todaro, Juan Santiago. Universidad Nacional del Nordeste. Facultad de Medicina; ArgentinaFil: Vidoz, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Adventitious root formation in flooded tomato plants: insights on auxin and ethylene interaction

Soil flooding, which results in a decline in the availability of oxygen for the submerged organs, negatively affects the growth and productivity of most crops. Although tomato (Solanum lycopersicum) is known for its sensitivity to waterlogging, its ability to produce adventitious roots (ARs) increases plant survival when oxygen decreases in the root zone. Ethylene entrapment by water may represent the first warning signal to the plant of waterlogging. Treatment with both the ethylene-biosynthesis inhibitor aminoethoxyvinylglycine (AVG) and 1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, resulted in a reduction of AR formation in waterlogged plants. Ethylene perceived by the Never Ripe receptor stimulated auxin transport. In a process requiring the Diageotropica gene, auxin accumulation in the stem triggers additional ethylene synthesis, which further stimulated a flux of auxin towards the flooded parts of the plant. Auxin accumulating in the base of the plant induces preformed root initials to grow. This response of tomato plants results in a new root system capable of replacing the original one when it has been damaged by submergence

Gibberellins modulate auxin responses during tomato (Solanum lycopersicum L.) fruit development

In tomato, auxin and gibberellins (GAs) interact with each other to drive fruit growth and development. While the role of auxin in directing GA biosynthesis and signal is already known, very little information has been obtained about GA-mediated control of auxin signalling and response. Interestingly, we show that gibberellic acid (GA 3 ) is able to modify the expression of several auxin signalling genes in the partial auxin-insensitive diageotropica (dgt) mutant, suggesting that GAs may override the control of DGT on auxin signal. Procera (pro) mutation, which confers a constitutively active GA signal, enhances the effects of exogenous auxin, indicating that PRO may act as a negative effector of auxin responses in fruits. Indeed, transcript modulation of some auxin/indole acetic acid and auxin response factor genes in auxin-treated dgt/pro fruits suggests that PRO controls their expression possibly bypassing DGT. It was also shown that GA biosynthesis, in response to auxin treatment, is largely controlled by DGT. It is therefore conceivable that the DGT-mediated increase of active GAs in auxin-treated or pollinated fruits would promote PRO degradation, which in turn activates part of the auxin signalling cascade.Fil: Mignolli, Francesco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Vidoz, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Picciarelli, Piero. Università degli Studi di Pisa; ItaliaFil: Mariotti, Lorenzo. Università degli Studi di Pisa; Itali

Plant regeneration of Lotononis bainesii Baker (Fabaceae) through cotyledon and leaf culture

Lotononis bainesii Baker is a promising perennial forage legume for subtropical regions. The development of tissue culture methods for in vitro plant regeneration is useful, for example, for the propagation of selected plants and germplasm conservation. In addition, it could also facilitate crop improvement methods. For this last purpose, we performed experiments to develop a tissue culture protocol for different genotypes within a cultivar and from different explants of L. bainesii. Plant regeneration was obtained for over 50% of L. bainesii cv. INIA Glencoe genotypes evaluated via cotyledon culture and 90% of genotypes evaluated by leaflet culture in a medium composed of Murashige and Skoog medium (MS) + 4.5 μM thidiazuron (TDZ). Bud elongation and rooting were obtained upon transfer onto MS + 0.044 µM 6-benzyladenine (BA) + 0.049 µM indolebutyric acid (IBA). Although immature leaflet culture resulted in a higher number of responsive genotypes than cotyledon culture, plants regenerated from cotyledons exhibited a higher survival rate when transferred to ex vitro conditions. Culture medium supplementation with either Picloram (PIC) or 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in friable callus, that did not grow when subcultured. Immature leaflet insertion areas (petiole tip area where the three leaflets are attached) from expanding leaves and pieces of immature leaflets were the most efficient explants for shoot bud induction. A recommended protocol for L. bainesii plant regeneration would be placing immature leaflet explants on MS + 4.5 μM TDZ for 30 days; followed by transfer onto MS + 0.044 µM BA + 0.049 µM IBA for bud elongation and rooting.Key words: Explant type, forage legume, organogenesis, plant regeneration, shoot bud, thidiazuron

Distribution and natural history notes on Tachymenis chilensis chilensis (Schlegel, 1837) (Reptilia: Serpentes: Dipsadidae) in Argentina

We revisit the distribution and natural history data of Tachymenis chilensis chilensis (Schlegel, 1837) in Argentina based on compiled and novel records, extending its northern and southern distribution from the previously known localities in Argentina. We recorded two prey items in Argentinean populations: Rhinella rubropunctata, reported for the first time, and Liolaemus pictus. Tachymenis c. chilensis is mainly found in forested habitats, generally near wetlands with abundant populations of amphibians. The latitudinal range occupied by T. c. chilensis in Argentina is similar to that in Chile, but its northern distribution limit reaches the lowest latitudes in Chile. This is probably due to the higher humidity levels in the western slopes of the Andes and the barrier effect of the highest mountain ranges in this area.Fil: Giraudo, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Vidoz, Félix. Administración de Parques Nacionales; ArgentinaFil: Arzamendia, Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Nenda, Santiago Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin