Leaf rolling as indicator of water stress in Cistus incanus from different provenances

Leaf movements such as leaf rolling affect plant physiological performance by reducing light capture. The relationship between leaf rolling and physiological traits under imposed water stress conditions was analyzed in two population of Cistus incanus. We tested the hypothesis that leaf rolling reflected physiological changes occurring during water stress irrespective of the different acclimation in order to cope with water stress. On the whole, our results confirmed our hypothesis since leaf rolling significantly reflected physiological activity changes. Moreover, leaf rolling might be involved in protecting the PSII complex under water stress during the progressive inhibition of photosynthetic metabolism. Thus, leaf rolling could be part of C. incanus adaptive strategy to cope with water stress by sustaining leaf turgor. As such, leaf rolling may be used as a morphological index to evaluate the progressive inhibition of photosynthesis irrespective of the different acclimation to cope with water stress

evergreen species response to mediterranean climate stress factors

Abstract: Recent climatic projections predict a decline in rainfall mainly during the summer period and an increase in air temperature for the Mediterranean basin, resulting in extended periods of soil water deficit. Mediterranean evergreen species attain drought resistance through different traits or combination of traits. The main objective of this research is to analyze the response of the evergreen species co-occurring in the Mediterranean maquis to variations in water availability and air temperature during the year. The results show that leaf structural traits significantly affect physiological traits as confirmed by the Partial Least Squares Regression analysis (PLS). In particular, the considered species have a similar leaf respiration (RL) trend during the year with the lowest rates in winter (mean 0.95 ± 0.44 µmol m-2 s-1) and the highest in drought (mean 3.05 ± 0.96 µmol m-2 s-1). Nevertheless, a different RL effect on gross photosynthesis (PG) during drought was observed. C. incanus, E. multiflora, R. officinalis and S. aspera have the highest RL/PG ratio (mean 0.54 ± 0.08), while Q. ilex, P. latifolia, P. lentiscus, A. unedo and E. arborea have the lowest (mean 0.22 ± 0.07). RL/PG ratio variations depend on the sensitivity of both the two parameters to drought. Considering the increase of the length and intensity of drought in the Mediterranean basin, and that the photosynthesis of Mediterranean evergreen species is frequently limited by sub-optimal conditions (i.e., water deficit, high light intensity and high air temperature), it is important to improve knowledge on RL, since it has a critical function in modulating carbon balance of Mediterranean species

photochemical performance of carpobrotus edulis in response to various substrate salt concentrations

Abstract Substrate salinity is one of the main abiotic factors limiting plant establishment, growth and distribution in coastal habitats. Nevertheless, few studies have investigated the interaction between salt concentration and duration of exposure on the physiology and growth of Carpobrotus edulis, an important invasive plant species growing in coastal dune habitats. In this study, four salinity treatment cycles of different length (three, six, twelve and twenty-four days) at salinity of 0 M, 0.1 M, 0.2 M and 0.3 M were imposed. A significant response in plant growth was elicited after 24 days of treatment. The main shoot length (MSL) and stem biomass (SBMS) increased by 11% and 4%, respectively at 0.1 M and by 25% and 6% at 0.2 M compared with the control. At 0.3 M MSL did not significantly differ from the control while SBMS was 18% lower. Moreover, C. edulis showed a high photoprotection mechanism efficiency resulting in a high carotenoid to chlorophyll ratio increase which was two, three and four times higher than the control at 0.1 M, 0.2 M and 0.3 M, respectively. Photochemically, the quantum yield of photosynthesis (ΦPSII) was 17%, 50% and 52% lower than the control at 0.1 M, 0.2 M and 0.3 M. The ΦPSII decrease was associated with a low leaf nitrogen content (NL) decrease (16%, 21% lower than the control at 0.1 M and 0.2 M, respectively). By contrast, NL had the highest decrease (41% lower than the control) at 0.3 M, which constrains the growth capacity. Overall, C. edulis was able to modulate its response to salinity. The salt stimulated shoot elongation at low or moderate salt concentrations could confer a competitive advantage making C. edulis even more efficient in establishing within the areas which it colonizes. Since the expansion of C. edulis may be enhanced by the forecasted increase in soil salinity, it will be of paramount importance to apply effective management practices in areas invaded by C. edulis to limit its expansion and preserve the native plant biodiversity

Regulation of leptin expression by 17beta-estradiol in human placental cells involves membrane associated estrogen receptor alpha

The placenta produces a wide number of molecules that play essential roles in the establishment and maintenance of pregnancy. In this context, leptin has emerged as an important player in reproduction. The synthesis of leptin in normal trophoblastic cells is regulated by different endogenous biochemical agents, but the regulation of placental leptin expression is still poorly understood. We have previously reported that 17β-estradiol (E 2) up-regulates placental leptin expression. To improve the understanding of estrogen receptor mechanisms in regulating leptin gene expression, in the current study we examined the effect of membrane-constrained E 2 conjugate, E-BSA, on leptin expression in human placental cells. We have found that leptin expression was induced by E-BSA both in BeWo cells and human placental explants, suggesting that E 2 also exerts its effects through membrane receptors. Moreover E-BSA rapidly activated different MAPKs and AKT pathways, and these pathways were involved in E 2 induced placental leptin expression. On the other hand we demonstrated the presence of ERα associated to the plasma membrane of BeWo cells. We showed that E 2 genomic and nongenomic actions could be mediated by ERα. Supporting this idea, the downregulation of ERα level through a specific siRNA, decreased E-BSA effects on leptin expression. Taken together, these results provide new evidence of the mechanisms whereby E 2 regulates leptin expression in placenta and support the importance of leptin in placental physiology.Fil: Gambino, Yésica Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Pérez Pérez, Antonio. Hospital Universitario Virgen Macarena; EspañaFil: Dueñas, José L.. Hospital Universitario Virgen Macarena; EspañaFil: Calvo, Juan Carlos. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sánchez Margalet, Víctor. Hospital Universitario Virgen Macarena; EspañaFil: Varone, Cecilia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin

A menthol-enhanced “cooling” energy gel does not influence laboratory time trial performance in trained runners

l-menthol (menthol) is an organic compound derived from peppermint which imparts a refreshing mint flavor and aroma to oral hygiene products, chewing gum, and topical analgesics. Menthol has been identified as a non-thermal sensory cooling strategy for athletes when ingested or mouth-rinsed during exercise in hot environments. Therefore, sports nutrition products delivering a controlled concentration of menthol could be beneficial for athletes exercising in the heat. We sought to test the performance and perceptual outcomes of a novel menthol energy gel during treadmill running in the heat (33 °C, 49% RH). Fourteen trained runners (mean ± SD; age: 31 ± 6 years, VO2max: 56.5 ± 10.1 mL·kg−1·min−1, BMI: 23.2 ± 2.4 kg/m2; six female) participated in a randomized, crossover, double-blind, and placebo-controlled study. A menthol-enhanced energy gel (0.5% concentration; MEN) or flavor-matched placebo (PLA) was ingested 5 min before and again at 20 and 40 min of a 40 min treadmill exercise preload at 60% VO2max, followed by a 20 min self-paced time trial. The total distance, vertical distance, perceptual measures (thermal comfort, thermal sensation, rating of perceived exertion, and affect), and cognitive performance via computerized neurocognitive assessment were measured. No difference between 20 min self-paced time trial total distance (MEN: 4.22 ± 0.54 km, PLA: 4.22 ± 0.55 km, p = 0.867), vertical distance (MEN: 49.2 ± 24.6 m, PLA: 44.4 ± 11.4 m, p = 0.516), or any perceptual measures was observed (all p > 0.05). Cognitive performance was not different between the trials (all p > 0.05). These results suggest that a menthol energy gel is not superior to a non-menthol gel in terms of performance or perception during treadmill running in the heat. More research is needed to confirm whether these findings translate to ecologically valid settings, including outdoor exercise in ambient heat and during competition

Leptin and Gestational Diabetes Mellitus

Emerging research has highlighted the importance of leptin in fetal growth and development, independent of its essential role in the regulation of feeding and energy metabolism. Leptin is now considered an important signaling molecule of the reproductive system, since it regulates the production of gonadotropins, the blastocyst formation and implantation, the normal placentation, as well as the feto-placental communication. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes like proliferation, protein synthesis, invasion, and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including gestational diabetes mellitus (GDM). Due to the relevant incidence of the GDM and the importance of leptin, we decided to review the latest information available about leptin action in normal and GDM pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction and pregnancy

Left ventricular surgical restoration for anteroseptal scars: Volume versus shape

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