Phosphorylation and Transport in the Na-K-2Cl Cotransporters, NKCC1 and NKCC2A, Compared in HEK-293 Cells

Na-K-2Cl cotransporters help determine cell composition and volume. NKCC1 is widely distributed whilst NKCC2 is only found in the kidney where it plays a vital role reabsorbing 20% of filtered NaCl. NKCC2 regulation is poorly understood because of its restricted distribution and difficulties with its expression in mammalian cell cultures. Here we compare phosphorylation of the N-termini of the cotransporters, measured with phospho-specific antibodies, with bumetanide-sensitive transport of K+ (86Rb+) (activity) in HEK-293 cells stably expressing fNKCC1 or fNKCC2A which were cloned from ferret kidney. Activities of transfected transporters were distinguished from those of endogenous ones by working at 37°C. fNKCC1 and fNKCC2A activities were highest after pre-incubation of cells in hypotonic low-[Cl−] media to reduce cell [Cl−] and volume during flux measurement. Phosphorylation of both transporters more than doubled. Pre-incubation with ouabain also strongly stimulated fNKCC1 and fNKCC2A and substantially increased phosphorylation, whereas pre-incubation in Na+-free media maximally stimulated fNKCC1 and doubled its phosphorylation, but inhibited fNKCC2A, with a small increase in its phosphorylation. Kinase inhibitors halved phosphorylation and activity of both transporters whereas inhibition of phosphatases with calyculin A strongly increased phosphorylation of both transporters but only slightly stimulated fNKCC1 and inhibited fNCCC2A. Thus kinase inhibition reduced phosphorylation and transport, and transport stimulation was only seen when phosphorylation increased, but transport did not always increase with phosphorylation. This suggests phosphorylation of the N-termini determines the transporters' potential capacity to move ions, but final activity also depends on other factors. Transport cannot be reliably inferred solely using phospho-specific antibodies on whole-cell lysates

Fruit development of two high oleic safflower (Carthamus tinctorius L.) cultivars

The purpose of this study was to describe fruit development in two high oleic safflower (Carthamus tinctorius L.) cultivars during four growing seasons. Pericarp histogenesis, and dynamics of pericarp and seed dry weight and fruit water content were studied. The dynamics of the pericarp and seed growth was similar between cultivars and years. The pericarp completed its growth before the seed. Pericarp potential size was already set at anthesis as no cell division was observed at this time. Maximum pericarp dry weight was achieved 8 days after anthesis, when cell wall lignification concluded. At this time, twinned prismatic simetric crystals had decreased in number and size respect to those observed at anthesis. Physiological maturity (maximum seed dry weight) was achieved between 17 and 25 days after anthesis. Similar pericarp growth rate and duration between cultivars and years were associated to similar maximum pericarp dry weight (17 mg), except in 2012. In this year, the higher maximum pericarp dry weight (20 mg) was only associated to a higher fruit volume (50 µL). Maximum seed dry weight (22 mg) was lower in CW88 OL than in CW99 OL, except in 2012. However, seed growth rate and time of physiological maturity were similar between cultivars. Fruit water content at physiological maturity (39%) was similar between cultivars. The recommended moisture (10-13%) at harvesting was achieved around 33 days after anthesis. The timing of the different morphological and histological events of safflower fruit development presented in this work sets a not-yet-existent conceptual framework, and constitutes an important tool for the interpretation and comparison of the effects of genotype, environment or agricultural management practices on crop yield and fruit quality.El objetivo de este trabajo fue describir el desarrollo del fruto de dos cultivares de cártamo (Carthamus tinctorius L.) alto oleico durante cuatro estaciones de crecimiento. Se estudió la histogénesis del pericarpio, y la dinámica del peso seco del pericarpio y de la semilla y del contenido de agua del fruto. La dinámica del crecimiento del pericarpio y de la semilla fue similar entre cultivares y años. El pericarpio completó su crecimiento antes que la semilla. El tamaño potencial del pericarpio ya estaba fijado en antesis ya que en ese momento no se observaron divisiones celulares. El máximo peso seco del pericarpio se alcanzó 8 días después de la antesis, momento en el que concluyó la lignificación de sus células. Al mismo tiempo, los pares de cristales prismáticos y simétricos habían disminuido en número y tamaño respecto de los observados en antesis. La madurez fisiológica (máximo peso seco de la semilla) se alcanzó entre los 17 y 25 días después de la antesis. La duración y tasa de crecimiento del pericarpio similares entre cultivares y años estuvieron asociadas a un similar máximo peso seco del pericarpio (17 mg), excepto en 2012. En este año, el mayor máximo peso seco del pericarpio (20 mg) estuvo únicamente asociado al mayor volumen del fruto (50 µL). El máximo peso seco de la semilla (22 mg) fue menor en CW88 OL respecto de CW99 OL, excepto en 2012. Sin embargo, la tasa de crecimiento de la semilla y el tiempo en que se alcanzó la madurez fisiológica fueron similares entre cultivares. El contenido de agua del fruto en madurez fisiológica (39%) fue similar entre cultivares. El porcentaje de humedad del fruto recomendado para la cosecha (10-13%) se alcanzó alrededor de los 33 días después de la antesis. El momento en que ocurren los diferentes eventos morfológicos e histológicos del desarrollo del fruto de cártamo presentados en este trabajo establece un marco conceptual inexistente, y constituye una herramienta importante para la interpretación y comparación del efecto del genotipo, el medio ambiente o las prácticas de manejo del cultivo sobre el rendimiento y la calidad del fruto de cártamo

Arid and Semiarid Rangelands of Argentina

Two thirds of continental Argentina are arid and semiarid rangelands. These rangelands include five phytogeographic regions: (1) Puna, (2) Chaco Occidental, (3) Monte, (4) Caldenal, and (5) Patagonia. This review includes and begins with a brief overview of the climate, soil, and vegetation characteristics of each region. After that, the major causes of degradation or desertification of these territories are indicated, together with the previous and current impacts on the water resources; the physicochemical and biological soil characteristics, and vegetation structure; productive activities; economy; and society. Fortunately, in contrast with various other arid and semiarid regions in the world, a threshold of losses of renewable natural resources has not yet been reached as a result of such degradation or desertification of the study ecological systems. Beyond this threshold, reestablishment of benefits which could have been obtained from rational (not abusive) utilization of those resources will be impossible. Our aim is an improved land use that allows sustainable production, the magnitude of which will depend upon its previous degree of degradation or desertification.Fil: Busso, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Fernandez, Osvaldo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Agronomía; Argentin