Puccinellia festucaeformis (Host) Parl.: Germinazione e crescita iniziale in funzione della salinità del substrato

Abstract

Puccinellia festucaeformis (Host) Parl.: germination and early growth on different salt substrates. Germination behaviour of Puccinellia festucaeformis seeds and early growth of seedlings at different experimental conditions was analysed. The following growth substrates were utilized: NaCl, KCl, KNO₃, MgCl₂, MgSO₄, Na₂SO₄, NaNO₃, CaCl₂ at the decreasing concentrations of 0.50, 0.25, 0.12, 0.06M. Caryopses were allowed to imbibe and grow at alternating temperatures (10°-20°C or 20°-30°C) in the dark for 3 days. Seedling were grown for 15 days, at controlled light and temperature conditions, in the same nutrient substrates as those used for the germination experiments.

The germination experiments showed a high tolerance to salts up to 0.25M solution and for the whole range of MgSO₄ concentrations. High growth temperatures increased the depressive effects of salt concentrations. Seedling growth was highly reduced when salt concentration was higher than 0.12M. High salt tolerance - maximum shoot and root growth - was showed by seedling allowed to grow on 0.50M MgSO₄.

Germination and growth condition of Puccinellia festucaeformis is discussed in relation to the ecological features of this species and to its possible importance as bioindicator of MgSO₄ rich natural substrates.     

Resumen del consenso FESNAD-SEEDO: recomendaciones nutricionales basadas en la evidencia para la prevención y el tratamiento del sobrepeso y la obesidad en adultos

This paper is a summary of the Spanish Federation of Nutrition, Food and Dietetics Associations (FESNAD) and the Spanish Association for the Study of Obesity (SEEDO) consensus document on the role of diet in prevention and treatment of overweight and obesity.To prepare this document, and in order to achieve the maximum evidence level possible, a systematic review was made of all medical literature published between January 1, 1996 and January 31, 2011 (15 years). The obtained findings were catalogued by evidence level following the Scottish Intercollegiate Guidelines Network system, and recommendations were produced based on data collected.As a result, 65 evidences and 31 recommendations applicable to obese adults without any other pathological process were produced.Evidences and resulting recommendations are provided, and the most significant findings are discussed.This consensus document is intended to provide healthcare professionals with a reference tool that may help them design dietary strategies for prevention and treatment of overweight and obesity.     

La douleur, la souffrance et le corps: enjeux pour la médecine

Pain is an unpleasant sensory, emotional and subjective experience that does not necessarily correlate directly with tissue damage. It allows us to avoid stimuli that cause bodily harm, yet its meaning extends beyond the ability to detect such stimuli: the definition of pain has epistemological and ethical significance. We always risk reducing pain to mere nociception by neglecting the multifactorial experience of consciousness or, on the other hand, overemphasizing, by neglecting the physical dimension, the suffering experienced. This problem creates a major barrier to understanding pain and has important consequences in medical practice, which we analyze in several areas: the relevance of the clinic in modern medicine, pathology (through the issues raised by fibromyalgia), neuroscience and brain imaging, and treatment (through a look at the placebo effect).     

Chimiothérapie anticancéreuse chez le mâle: risques pour la descendance

Up to now, studies concerning the progeny of males undergoing chemotherapy have been difficult to interpret because of their heterogeneity and conflicting nature. Morever, the long term follow up of children has not been carried out. Experimental studies carried out with the cytostatic drug cyclophosphamide have shown that if mating of male rats takes place during the treatment, the frequency of post-implantation losses and fetal malformations increases. If this mating takes place after a recovery period of one to two seminiferous cycles, there is no malformation but only neonatal deaths, and behavioral disorders in adult progeny including diminished learning capacity. These abnormalities are inherited and can present the characteristics of dominant autosomic syndromes. Biochemical analyses of the brains of the first and second generation offspring from treated males show a decrease in two biochemical substrates of memory: hippocampal choline acetyltransferase and fronto-parietal cortex norepinephrine. Abnormalities can also present complex genetic rearrangements revealed in the third generation by, amongst other things, increases in weight gain. Finally, the experimental results suggest that genetic repair may be possible with time. These data and the uncertainty concerning the consequences of chemotherapy in males should systematically lead to:

- the cryopreservation of sperm before any mutagenic treatment;

- a minimum of two years contraception from the end of treatment;

- the long term follow up of children born from treated fathers.

     

Why are antlion larvae rare under the leaf litter? Testing the hypothesis of improper trap maintenance¿Por qué las larvas del león de las hormigas son tan raras bajo la hojarasca? Probando la hipótesis del mantenimiento inadecuado de las trampas

1. Understanding why animals avoid some locations is needed to improve the theory of habitat selection. This is key in semi-sedentary organisms, such as antlion larvae, because once established they rarely move, and their performance largely depends on local environmental conditions.
2. Antlion larvae are sit-and-wait predators that build conical pitfall traps in sandy soils to capture passing prey. They clean constantly their traps, expelling soil, prey carcasses and debris out of the pit to maintain their trapping success. Therefore, we propose that they avoid soils with leaf litter because leaves hinder the maintenance of their pits; a hypothesis that has not yet been tested.
3. We first demonstrated that antlion larvae (Myrmeleon inmaculatus) are rare from soils with leaf litter in a tropical semi-deciduous forest in Mexico. We then experimentally tested the effect of leaf litter on pit maintenance by adding debris in 90 antlion traps, 45 of which were covered with a leaf, and 45 remained uncovered. Two hours after adding the debris, we recorded its location and quantified the variation in depth and diameter of the pits.
4. Larvae in uncovered traps were twice as effective at cleaning up the debris than larvae in covered traps. Furthermore, in just 2 h, covered traps were on average 21% shallower than control traps, probably because unsuccessful attempts to clean debris caused sand slides to fill the pit partially.
5. Leaf litter seems to hinder the proper maintenance of antlion traps, explaining at least partially, why these animals are rare under leaf litter.

     

Hypothèse : le modèle du lieu de rencontre pour la maladie des prions

Prions are responsible for spongiform diseases such as scrapie and bovine spongiform encephalopathy. It is now generally accepted that the disease mechanism involves the conversion from the normal form, PrP^C, to the pathogenic form, PrP^Sc, and that this isoform is infectious. In the case of scrapie, 15 different forms of the disease have been described and some of these different phenotypes can be conferred by infectious prions that are themselves encoded by normal genes. We propose here that a prion with an altered structure has a correspondingly altered preference for lipids; this altered preference creates a proteolipid domain containing different lipids and other factors such as chaperonins and enzymes responsible for post-translational modifications. Normal prions associated with this abnormal domain adopt the conformation dictated by its lipidic composition (and by the other factors present) and so acquire the lipidic preference of the original pathogenic prions. These transformed prions could then create new proteolipid domains. This process may be considered as semi-conservative replication in which prion and lipids are analogous to the Watson and Crick strands and the proteolipid domain to the double helix itself.