Variaciones estacionales en el crecimiento de larvas de anchoíta (Engraulis anchoita) en la zona costera argentina

Age and growth rates of the anchovy larvae (Engraulis anchoita) in Argentine waters were estimated by analysing daily growth increments in sagittal otoliths under light microscope. The samples were collected during 2000 on the Argentine coastal shelf using a Bongo net. A total of 251 larvae were analysed (size range 3.5 to 12.2 mm standard length). Length-at-age and standard length-otolith radius relationships were best described by linear models. We put forward the hypothesis of differential larval growth in anchovy in relation to seasonality. Mean growth rates at four days before capture were determined by back-calculation and analysed in relation to temperature. The growth rate values obtained from the linear growth models were 0.51 mm day-1 (spring), 0.41 mm day-1 (summer) and 0.42 mm day-1 (autumn). Significant variations were detected between spring and summer and between spring and autumn. These variations do not seem to be associated with a thermal influence.Se determinó la edad y el crecimiento de larvas de anchoíta (Engraulis anchoita) mediante el conteo y medición de los incrementos diarios de los otolitos sagitta. Las larvas fueron capturadas en la Plataforma Costera Argentina durante el año 2000 por medio de una red Bongo. Se analizaron un total de 251 larvas entre 3.5 a 12.2 mm. Las relaciones talla-edad y talla -radio del otolito se representaron mediante modelos lineales para cada estación del año (primavera-verano-otoño). La mayor tasa de crecimiento, calculada como la pendiente de los modelos talla -edad, se registró en primavera (0.51 mm dia-1) la menor en verano (0.41 mm dia-1), mientras que otoño presentó una tasa de crecimiento intermedia (0.42 mm dia-1). Si bien no se encontraron diferencias significativas en las tasas de crecimiento entre verano y otoño, sí las hubo entre primavera y verano y entre primavera y otoño. Se calculó una tasa de crecimiento larvaria 4 días antes de la captura mediante retrocálculo y se la relacionó con la temperatura. Las variaciones en el crecimiento no parecen relacionarse con la influencia térmica

Parental effects and reproductive potential of fish and marine invertebrates: Cross-generational impact of environmental experiences

The reproductive success of aquatic animals depends on a complex web of relationships between the environment, the attributes of the reproductive individuals and human-induced selection. All of them are manifested directly or indirectly through parental effects, which can also compensate for certain external impacts. Parental effects refer to the influence that the phenotype and environmental conditions in which individuals develop exert on the phenotype of their offspring, and they can even have transgenerational impact. This paper describes the different types of parental effects and reviews the published literature to analyze the causes of their variation and their impact on reproductive resilience and population dynamics.Versión del edito

Nanostructured Systems Containing Rutin: In Vitro Antioxidant Activity and Photostability Studies

The improvement of the rutin photostability and its prolonged in vitro antioxidant activity were studied by means of its association with nanostructured aqueous dispersions. Rutin-loaded nanocapsules and rutin-loaded nanoemulsion showed mean particle size of 124.30 ± 2.06 and 124.17 ± 1.79, respectively, polydispersity index below 0.20, negative zeta potential, and encapsulation efficiency close to 100%. The in vitro antioxidant activity was evaluated by the formation of free radical ·OH after the exposure of hydrogen peroxide to a UV irradiation system. Rutin-loaded nanostructures showed lower rutin decay rates [(6.1 ± 0.6) 10−3 and (5.1 ± 0.4) 10−3 for nanocapsules and nanoemulsion, respectively] compared to the ethanolic solution [(35.0 ± 3.7) 10−3 min−1] and exposed solution [(40.1 ± 1.7) 10−3 min−1] as well as compared to exposed nanostructured dispersions [(19.5 ± 0.5) 10−3 and (26.6 ± 2.6) 10−3, for nanocapsules and nanoemulsion, respectively]. The presence of the polymeric layer in nanocapsules was fundamental to obtain a prolonged antioxidant activity, even if the mathematical modeling of the in vitro release profiles showed high adsorption of rutin to the particle/droplet surface for both formulations. Rutin-loaded nanostructures represent alternatives to the development of innovative nanomedicines

Perilipin 2 (PLIN2)-Deficiency Does Not Increase Cholesterol-Induced Toxicity in Macrophages

Interventions on macrophages/foam cells to redirect intracellular cholesterol towards efflux pathways could become a very valuable addition to our therapeutic arsenal against atherosclerosis. However, certain manipulations of the cholesteryl ester cycle, such as the inhibition of ACAT1, an ER-resident enzyme that re-esterifies cholesterol, are not well tolerated. Previously we showed that targeting perilipin-2 (PLIN2), a major lipid droplet (LD)-associated protein in macrophages, prevents foam cell formation and protects against atherosclerosis. Here we have assessed the tolerance of PLIN2-deficient bone marrow derived macrophages (BMM) to several lipid loading conditions similar to the found during atherosclerosis development, including exposure to modified low-density lipoprotein (mLDL) and 7-ketocholesterol (7-KC), a free cholesterol (FC) metabolite, in media with or without cholesterol acceptors. BMM isolated from mice that do or do not express PLIN2 were tested for apoptosis (TUNEL and cleaved caspase-3), ER stress (CHOP induction and XBP-1 splicing), and inflammation (TNF-α and IL-6 mRNA levels). Like in other cell types, PLIN2 deficiency impairs LD buildup in BMM. However, while most stress parameters were elevated in macrophages under ACAT inhibition and 7-KC loading, PLIN2 inactivation was well tolerated. The data support the safety of targeting PLIN2 to prevent foam cell formation and atherosclerosis

Ecología reproductiva y pesquerías en el contexto iberoamericano

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Effect of cholesterol on the dipole potential of lipid membranes

The membrane dipole potential, ψd, is an electrical potential difference with a value typically in the range 150 – 350 mV (positive in the membrane interior) which is located in the lipid headgroup region of the membrane, between the linkage of the hydrocarbon chains to the phospholipid glycerol backbone and the adjacent aqueous solution. At its physiological level in animal plasma membranes (up to 50 mol%), cholesterol makes a significant contribution to ψd of approximately 65 mV; the rest arising from other lipid components of the membrane, in particular phospholipids. Via its effect on ψd, cholesterol may modulate the activity of membrane proteins. This could occur through preferential stabilization of protein conformational states. Based on its effect on ψd, cholesterol would be expected to favour protein conformations associated with a small local hydrophobic membrane thickness. Via its membrane condensing effect, which also produces an increase in ψd, cholesterol could further modulate interactions of polybasic cytoplasmic extensions of membrane proteins, in particular P-type ATPases, with anionic lipid headgroups on the membrane surface, thus leading to enhanced conformational stabilization effects and changes to ion pumping activity.Australian Research Counci