Discovery of an ebolavirus-like filovirus in europe

Filoviruses, amongst the most lethal of primate pathogens, have only been reported as natural infections in sub-Saharan Africa and the Philippines. Infections of bats with the ebolaviruses and marburgviruses do not appear to be associated with disease. Here we report identification in dead insectivorous bats of a genetically distinct filovirus, provisionally named Lloviu virus, after the site of detection, Cueva del Lloviu, in Spain.     

Antidepressant-like effect of a Ginkgo biloba extract (EGb761) in the mouse forced swimming test: role of oxidative stress

EGb761 is a well-defined mixture of active compounds extracted from Ginkgo biloba leaves. This extract is used clinically due to its neuroprotective effects, exerted probably via its potent antioxidant or free radical scavenger action. Previous studies suggest that oxidative stress, via free radical production, may play an important role in depression and animal models for depression-like behavior. Preclinical studies have suggested that antioxidants may have antidepressants properties. The aim of this study was to investigate the antidepressant-like of EGb761 due to its antioxidant role against oxidative stress induced in the forced swimming test, the most widely used preclinical model for assessing antidepressant-like behavior. Male BALB/c mice were pretreated with EGb761 (10 mg/kg, ip) daily for 17 days followed by the forced swimming test and spontaneous locomotor activity. Animals were sacrificed to evaluate lipid peroxidation, different antioxidant enzyme activities, serotonin and dopamine content in midbrain, hippocampus and prefrontal cortex. EGb761 significantly decreased the immobility time (39%) in the forced swimming test. This antidepressant-like effect of EGb761 was associated with a reduction in lipid peroxidation and superoxide radical production (indicated by a downregulation of Mn-superoxide dismutase activity), both of which are indicators of oxidative stress. The protective effect of EGb761 is not related to excitatory or inhibitory effects in locomotor activity, and was also associated with the modulation of serotonergic and dopaminergic neurotransmission. It is suggested that EGb761 produces an antidepressant-like effect, and that an antioxidant effect against oxidative stress may be partly responsible for its observed neuroprotective effects.     

Cognitive impairment and the risk of falling in the elderly

Risk of fall is significantly increased in old people with cognitive decline due to specific associations between gait parameters and cognition. This association has recently been demonstrated, there being increasing evidence that cognitive domains such as attention, executive function and types of memory are critical for the correct regulation of gait. Gait disturbances can appear as early predictors of dementia in elderly patients. In the assessment of the fall risk, the use of dual tasks is novel, simple and relevant, especially in cognitive decline. Evidence for interventions in this population is limited, with vitamin D and physical exercise being the most encouraging, for decreasing the risk of fall in dementia.     

Age at menarche in urban Argentinian girls: association with biological and socioeconomic factors

Age at menarche is regarded as a sensitive indicator of physical, biological, and psychosocial environment. The aim of this study was to determine the age at menarche and its association with biological and socioeconomic factors in girls from Santa Rosa (La Pampa, Argentina). An observational cross-sectional study was carried out on 1,221 schoolgirls aged 9-15 years. Menarche data were obtained by the status-quo method. Height, sitting height, weight, arm circumference, tricipital and subscapular skinfolds were measured. We also calculated body mass index, measures of body composition and proportions, and fat distribution. To assess socioeconomic factors, parents completed a self-administered questionnaire about their occupation and education, family size, household, and other family characteristics. The median age at menarche - estimated by the logit method--was 12.84 years (95% CI: 12.71, 12.97). Compared with their premenarcheal age peers, postmenarcheal girls had greater anthropometric dimensions through age 12. After this age, only height was higher in the latter group. Data were processed by fitting two logistic regressions, both including age. The first model included anthropometric variables and birth weight, while the second model included the socioeconomic variables. The significant variables derived from each model were incorporated into a new regression: height, sitting height ratio (first model), and maternal education (second model). These three variables remained significantly associated with menarche. The results suggest a relationship between linear growth and menarche and agree with those found in other populations where the advancement of menarche is associated with improved living conditions. In relatively uniform urban contexts, maternal education may be a good proxy for the standard of living.     

Revision of the orchid bee subgenus Euglossella (Hymenoptera, Apidae), Part I, The decorata species group

Euglossella, one of the most distinctive subgenera of orchid bees of the genus Euglossa, is composed of two characteristic assemblages of species, one of them comprising bees bearing the strongly metallic integument trademark of the genus (viridis species group), and the other consisting of bees with a brown integument shaded with metallic iridescence (decorata species group). Here we provide the first of two parts of a revision of Euglossella, providing diagnostic definitions for the subgenus, the decorata species group, and all the species included therein. Six species are included in the decorata group, one new: Euglossa (Euglossella) aurantia, sp. n.; Euglossa (Euglossella) apiformis Schrottky, resurrected status; Euglossa (Euglossella) decorata Smith, revised status; Euglossa (Euglossella) singularis Mocsáry, revised status; Euglossa (Euglossella) cosmodora Hinojosa-Díaz and Engel; and Euglossa (Euglossella) perpulchra Moure and Schlindwein. Euglossa meliponoides Ducke and Euglossa urarina Hinojosa-Díaz and Engel are newly synonymized under Euglossa decorata, Euglossa decorata ruficauda Cockerell is synonymized under Euglossa singularis, and a neotype is designated for Euglossa apiformis.     

Müller glial cell-provided cellular light guidance through the vital guinea-pig retina

In vertebrate eyes, images are projected onto an inverted retina where light passes all retinal layers on its way to the photoreceptor cells. Light scattering within this tissue should impair vision. We show that radial glial (Müller) cells in the living retina minimize intraretinal light scatter and conserve the diameter of a beam that hits a single Müller cell endfoot. Thus, light arrives at individual photoreceptors with high intensity. This leads to an optimized signal/noise ratio, which increases visual sensitivity and contrast. Moreover, we show that the ratio between Müller cells and cones-responsible for acute vision-is roughly 1. This suggests that high spatiotemporal resolution may be achieved by each cone receiving its part of the image via its individual Müller cell-light guide.     

Nitric oxide signaling: classical, less classical, and nonclassical mechanisms

Although nitric oxide (NO) was identified more than 150 years ago and its effects were clinically tested in the form of nitroglycerine, it was not until the decades of 1970-1990 that it was described as a gaseous signal transducer. Since then, a canonical pathway linked to cyclic GMP (cGMP) as its quintessential effector has been established, but other modes of action have emerged and are now part of the common body of knowledge within the field. Classical (or canonical) signaling involves the selective activation of soluble guanylate cyclase, the generation of cGMP, and the activation of specific kinases (cGMP-dependent protein kinases) by this cyclic nucleotide. Nonclassical signaling alludes to the formation of NO-induced posttranslational modifications (PTMs), especially S-nitrosylation, S-glutathionylation, and tyrosine nitration. These PTMs are governed by specific biochemical mechanisms as well as by enzymatic systems. In addition, a less classical but equally important pathway is related to the interaction between NO and mitochondrial cytochrome c oxidase, which might have important implications for cell respiration and intermediary metabolism. Cross talk trespassing these necessarily artificial conceptual boundaries is progressively being identified and hence an integrated systems biology approach to the comprehension of NO function will probably emerge in the near future.     

A Hierarchical Approach to Cooperativity in Macromolecular and Self-Assembling Binding Systems

The study of complex macromolecular binding systems reveals that a high number of states and processes are involved in their mechanism of action, as has become more apparent with the sophistication of the experimental techniques used. The resulting information is often difficult to interpret because of the complexity of the scheme (large size and profuse interactions, including cooperative and self-assembling interactions) and the lack of transparency that this complexity introduces into the interpretation of the indexes traditionally used to describe the binding properties. In particular, cooperative behaviour can be attributed to very different causes, such as direct chemical modification of the binding sites, conformational changes in the whole structure of the macromolecule, aggregation processes between different subunits, etc. In this paper, we propose a novel approach for the analysis of the binding properties of complex macromolecular and self-assembling systems. To quantify the binding behaviour, we use the global association quotient defined as K _c = [occupied sites]/([free sites] L), L being the free ligand concentration. K _c can be easily related to other measures of cooperativity (such as the Hill number or the Scatchard plot) and to the free energies involved in the binding processes at each ligand concentration. In a previous work, it was shown that K_c could be decomposed as an average of equilibrium constants in two ways: intrinsic constants for Adair binding systems and elementary constants for the general case. In this study, we show that these two decompositions are particular cases of a more general expression, where the average is over partial association quotients, associated with subsystems from which the system is composed. We also show that if the system is split into different subsystems according to a binding hierarchy that starts from the lower, microscopic level and ends at the higher, aggregation level, the global association quotient can be decomposed following the hierarchical levels of macromolecular organisation. In this process, the partial association quotients of one level are expressed, in a recursive way, as a function of the partial quotients of the level that is immediately below, until the microscopic level is reached. As a result, the binding properties of very complex macromolecular systems can be analysed in detail, making the mechanistic explanation of their behaviour transparent. In addition, our approach provides a model-independent interpretation of the intrinsic equilibrium constants in terms of the elementary ones.