Muscarinic acetylcholine receptors mediate oligodendrocyte progenitor survival through Src-like tyrosine kinases and PI3K/Akt pathways

The function of muscarinic acetylcholine receptors expressed in oligodendrocytes and in myelin has remained largely undetermined. Here we present evidence that incubation of oligodendrocyte progenitors, deprived of growth factor, with the acetylcholine analog carbachol significantly reduced cell death by apoptosis and blocked caspase-3 cleavage. This protective effect was reversed by atropine, a muscarinic acetylcholine receptor antagonist, as well as by specific inhibitors of intracellular signaling molecules, including phosphatidylinositol 3-kinase (Wortmannin and LY294002), Akt (Akt inhibitor III) and Src-like tyrosine kinases (PP2), but not by the mitogen-activated protein kinase kinase inhibitor, PD98059. Activation of Akt by carbachol was antagonized by atropine and inhibited by LY294002 and PP2. The Src-like tyrosine kinase inhibitor, PP2, also reduced carbachol stimulation of extracellular signal-regulated kinases 1/2 and cAMP-response element binding protein in a dose-dependent manner. Furthermore, carbachol increased tyrosine-phosphorylation of Fyn, a member of the Src-like tyrosine kinases. These results indicate that muscarinic acetylcholine receptors play an important role in oligodendrocyte progenitor survival through transduction pathways involving activation of Src-like tyrosine kinases and phosphatidylinositol 3-kinase/Akt.     

Fermentation behaviour and volatile compound production by agave and grape must yeasts in high sugar Agave tequilana and grape must fermentations

Few studies have been performed on the characterization of yeasts involved in the production of agave distilled beverages and their individual fermentation properties. In this study, a comparison and evaluation of yeasts of different origins in the tequila and wine industries were carried out for technological traits. Fermentations were carried out in high (300 g l⁻¹) and low (30 g l⁻¹) sugar concentrations of Agave tequilana juice, in musts obtained from Fiano (white) and Aglianico (red) grapes and in YPD medium (with 270 g l⁻¹ of glucose added) as a control. Grape yeasts exhibited a reduced performance in high-sugar agave fermentation, while both agave and grape yeasts showed similar fermentation behaviour in grape musts. Production levels of volatile compounds by grape and agave yeasts differed in both fermentations.     

Endophytic Bacteria Improve Seedling Growth of Sunflower Under Water Stress, Produce Salicylic Acid, and Inhibit Growth of Pathogenic Fungi

Endophytic bacterial strains SF2 (99.9% homology with Achromobacter xylosoxidans), and SF3 and SF4 (99.9% homology with Bacillus pumilus) isolated from sunflower grown under irrigation or drought were selected on the basis of plant growth-promoting bacteria (PGPB) characteristics. Aims of the study were to examine effects of inoculation with SF2, SF3, and SF4 on sunflower cultivated under water stress, to evaluate salicylic acid (SA) production by these strains in control medium or at Ψa = ?2.03 MPa, and to analyze effects of exogenously applied SA, jasmonic acid (JA), bacterial pellets, and bacterial supernatants on growth of pathogenic fungi Alternaria sp., Sclerotinia sp., and Verticillum sp. Growth response to bacterial inoculation was studied in two inbred lines (water stress-sensitive B59 and water stress-tolerant B71) and commercial hybrid Paraiso 24. Under both water stress and normal conditions, plant growth following inoculation was more strongly enhanced for Paraiso 24 and B71 than for B59. All three strains produced SA in control medium; levels for SF3 and SF4 were higher than for SF2. SA production was dramatically higher at Ψa = ?2.03 MPa. Exogenously applied SA or JA caused a significant reduction of growth for Sclerotinia and a lesser reduction for Alternaria and Verticillum. Fungal growth was more strongly inhibited by bacterial pellets than by bacterial supernatants. Our findings indicate that these endophytic bacteria enhance growth of sunflower seedlings under water stress, produce SA, and inhibit growth of pathogenic fungi. These characteristics are useful for formulation of inoculants to improve growth and yield of sunflower crops.     

Short-Term Evaluation of the Impact of a Fortified Food Aid Program on the Micronutrient Nutritional Status of Argentinian Pregnant Women

We studied the impact of a food supplementation program (Plan Más Vida (PMV)) on the micronutrient nutritional condition of pregnant women from low-income families 1 year after its implementation. The food program provided supplementary diet (wheat and maize—fortified flour, rice or sugar, and fortified soup). We performed a prospective, nonexperimental, cross-sectional study in the province of Buenos Aires, Argentina, evaluating pregnant women at baseline (n?=?164) and 1 year after PMV implementation (n?=?108). Biochemical tests (hemogram, ferritin, vitamin A, zinc, and folic acid), anthropometric assessments (weight and height), and dietary surveys (24 h recall) were performed at the two study points. One year after PMV implementation, no significant changes in anthropometric values were observed. Folic acid deficiency and the risk of vitamin A deficiency (retinol, 20–30 μg/dl) decreased significantly (35.8 to 6.1 % and 64 to 41 %, respectively; p?<?0.000). Anemia and prevalence of iron and zinc deficiency values did not change. Diet survey results showed that although nutrient intake increased significantly, it was still below recommendations. Implementation of the PMV and of the government nutritional strategies had a high impact on the prevalence of folic acid deficiency. We also observed a decrease in the risk of vitamin A deficiency, and no impact on iron and zinc nutritional status. Adherence to the specific fortified food (soup) was not good and intra-family dilution and distribution of food was high.     

Inhibition pattern of sulfamide-related compounds in binding to carbonic anhydrase isoforms I,II, VII,XII and XIV

A set of sulfamides and sulfamates were synthesized and tested against several isoforms of carbonic anhydrase: CA I, CA II, CA VII, CA XII and CA XIV. The biological assays showed a broad range of inhibitory activity, and interesting results were found for several compounds in terms of activity (K_i <1 μm) and selectivity: some aromatic sulfamides are active against CA I, CA II and/or CA VII; while they are less active in CA XII and CA XIV. On the other hand, bulky sulfamides are selective to CA VII. To understand the origin of the different inhibitory activity against each isozyme we used molecular modeling techniques such as docking and molecular dynamic simulations.     

Caenorhabditis elegans Neuromuscular Junction: GABA Receptors and Ivermectin Action

The prevalence of human and animal helminth infections remains staggeringly high, thus urging the need for concerted efforts towards this area of research. GABA receptors, encoded by the unc-49 gene, mediate body muscle inhibition in Caenorhabditis elegans and parasitic nematodes and are targets of anthelmintic drugs. Thus, the characterization of nematode GABA receptors provides a foundation for rational anti-parasitic drug design. We therefore explored UNC-49 channels from C. elegans muscle cultured cells of the first larval stage at the electrophysiological and behavioral levels. Whole-cell recordings reveal that GABA, muscimol and the anthelmintic piperazine elicit macroscopic currents from UNC-49 receptors that decay in their sustained presence, indicating full desensitization. Single-channel recordings show that all drugs elicit openings of ∼2.5 pA (+100 mV), which appear either as brief isolated events or in short bursts. The comparison of the lowest concentration required for detectable channel opening, the frequency of openings and the amplitude of macroscopic currents suggest that piperazine is the least efficacious of the three drugs. Macroscopic and single-channel GABA-activated currents are profoundly and apparently irreversibly inhibited by ivermectin. To gain further insight into ivermectin action at C. elegans muscle, we analyzed its effect on single-channel activity of the levamisol-sensitive nicotinic receptor (L-AChR), the excitatory receptor involved in neuromuscular transmission. Ivermectin produces a profound inhibition of the frequency of channel opening without significant changes in channel properties. By revealing that ivermectin inhibits C. elegans muscle GABA and L-AChR receptors, our study adds two receptors to the already known ivermectin targets, thus contributing to the elucidation of its pleiotropic effects. Behavioral assays in worms show that ivermectin potentiates piperazine-induced paralysis, thus suggesting that their combination is a good strategy to overcome the increasing resistance of parasites, an issue of global concern for human and animal health.     

Unusual dengue virus 3 epidemic in Nicaragua, 2009

The four dengue virus serotypes (DENV1-4) cause the most prevalent mosquito-borne viral disease affecting humans worldwide. In 2009, Nicaragua experienced the largest dengue epidemic in over a decade, marked by unusual clinical presentation, as observed in two prospective studies of pediatric dengue in Managua. From August 2009-January 2010, 212 dengue cases were confirmed among 396 study participants at the National Pediatric Reference Hospital. In our parallel community-based cohort study, 170 dengue cases were recorded in 2009-10, compared to 13-65 cases in 2004-9. In both studies, significantly more patients experienced "compensated shock" (poor capillary refill plus cold extremities, tachycardia, tachypnea, and/or weak pulse) in 2009-10 than in previous years (42.5% [90/212] vs. 24.7% [82/332] in the hospital study (p<0.001) and 17% [29/170] vs. 2.2% [4/181] in the cohort study (p<0.001). Signs of poor peripheral perfusion presented significantly earlier (1-2 days) in 2009-10 than in previous years according to Kaplan-Meier survival analysis. In the hospital study, 19.8% of subjects were transferred to intensive care, compared to 7.1% in previous years - similar to the cohort study. DENV-3 predominated in 2008-9, 2009-10, and 2010-11, and full-length sequencing revealed no major genetic changes from 2008-9 to 2010-11. In 2008-9 and 2010-11, typical dengue was observed; only in 2009-10 was unusual presentation noted. Multivariate analysis revealed only "2009-10" as a significant risk factor for Dengue Fever with Compensated Shock. Interestingly, circulation of pandemic influenza A-H1N1 2009 in Managua was shifted such that it overlapped with the dengue epidemic. We hypothesize that prior influenza A H1N1 2009 infection may have modulated subsequent DENV infection, and initial results of an ongoing study suggest increased risk of shock among children with anti-H1N1-2009 antibodies. This study demonstrates that parameters other than serotype, viral genomic sequence, immune status, and sequence of serotypes can play a role in modulating dengue disease outcome.     

Cell replacement therapies for nervous system regeneration

The adult brain was thought to be a slowly decaying organ, a sophisticated but flawed machine condemned to inevitable decline. Today we know that the brain is more plastic than previously assumed, as most prominently demonstrated by the constitutive birth of new neurons that occurs in selected regions of the adult brain, even in humans. However, the overall modest capacity for endogenous repair of the central nervous system (CNS) has sparked interest in understanding the barriers to neuronal regeneration and in developing novel approaches to enable neuronal and circuit repair for therapeutic benefit in neurodegenerative disorders and traumatic injuries. Scientists recently assembled in Baeza, a picturesque town in the south of Spain, to discuss aspects of CNS regeneration. The picture that emerged shows how an integrated view of developmental and adult neurogenesis may inform the manipulation of neural progenitors, differentiated cells, and pluripotent stem cells for therapeutic benefit and foster new understanding of the inner limits of brain plasticity.     

Resveratrol Induces Apoptosis-Like Death and Prevents In Vitro and In Vivo Virulence of Entamoeba histolytica

Entamoeba histolytica causes amoebiasis, an infection that kills 100,000 individuals each year. Metronidazole and its derivatives are currently used against this protozoan, but these drugs present adverse effects on human health. Here, we investigated the effect of resveratrol (a natural compound) on E. histolytica trophozoites viability, as well as its influence on the parasite virulence. Trophozoites growth was arrested by 72 μM resveratrol and the IC₅₀ was determined as 220 μM at 48 h. Cells appeared smaller, rounded and in clusters, with debris-containing vacuoles and with abnormally condensed chromatin. Resveratrol triggered reactive oxygen species production. It caused lipid peroxidation and produced phosphatidylserine externalization and DNA fragmentation this latter evidenced by TUNEL assays. It also provoked an increase of intracellular Ca²⁺ concentration, activated calpain and decreased superoxide dismutase activity, indicating that an apoptosis-like event occurred; however, autophagy was not detected. Cytopathic activity, phagocytosis, encystment and in vivo virulence were diminished dramatically by pre-incubation of trophozoites with resveratrol, evidencing that resveratrol attenuated the trophozoite virulence in vitro. Interestingly, after the inoculation of virulent trophozoites, animals treated with the drug did not develop or developed very small abscesses. Our findings propose that resveratrol could be an alternative to contend amoebiasis.