Synthetic derivatives of the alpha- and beta-amyrin triterpenes and their antinociceptive properties

Fifteen different derivatives of an alpha- and beta-amyrin mixture were synthesized by acylation with appropriate anhydride or acid chlorides and oxidation in the presence of tert-butyl chromate or PCC. The molecular structures of the obtained compounds were confirmed by means of IR and (1)H NMR spectra. The compounds were screened for antinociceptive activity using the acetic acid pain model. The 3-O-acyl derivatives alpha- and beta-amyrin propionate 4, alpha- and beta-amyrin hexanoate 6, and alpha- and beta-amyrin octanoate 7 were found to be the most active compounds of the series. In addition, we also have found that alpha- and beta-amyrin octanoate 7 was able to reduce acetic acid-induced abdominal constriction when administered by oral route. Furthermore, this compound reduced the nociceptive response induced by intraplantar injection of formalin.     

A new hadrosaurid dentary from the latest Maastrichtian of the Pyrenees (north Spain) and the high diversity of the duck-billed dinosaurs of the Ibero-Armorican Realm at the very end of the Cretaceous

In the latest Maastrichtian, the European hadrosauroid fauna was more diverse than those of North America and Asia. The European record of hadrosaurid dentaries is an example of this diversity, and most of the sites with mandibular remains are located in the Ibero-Armorican Realm. Within the Iberian Peninsula, most of the remains are located in the Tremp Basin (South Central Pyrenees). Two of the three valid hadrosaurid taxa defined in this basin are from the Blasi sites (Arén, Huesca province): Arenysaurus ardevoli (Blasi-3) and Blasisaurus canudoi (Blasi-1). A new locality in Blasi (Blasi 3.4) has provided a new dentary from an indeterminate euhadrosaurid. This dentary presents some characters intermediate between Arenysaurus and Blasisaurus, some characters similar to Pararhabdodon isonensis (from the nearby province of Lleida), and some characters of its own. Nevertheless, due to its fragmentary character, without dentition or its edentulous anterior part, it cannot be determined above the level of Euhadrosauria. It thus represents a fourth Iberian euhadrosaurian taxon in the Ibero-Armorican Realm, different from Arenysaurus, Blasisaurus and Pararhabdodon, increasing the diversity of hadrosauroids in this realm at the very end of the Cretaceous.     

Interaction of a peptide corresponding to the loop domain of the S2 SARS-CoV virus protein with model membranes

The severe acute respiratory syndrome coronavirus (SARS-CoV) envelope spike (S) glycoprotein is responsible for the fusion between the membranes of the virus and the target cell. In the case of the S2 domain of protein S, it has been found a highly hydrophobic and interfacial domain flanked by the heptad repeat 1 and 2 regions; significantly, different peptides pertaining to this domain have shown a significant leakage effect and an important plaque formation inhibition, which, similarly to HIV-1 gp41, support the role of this region in the fusion process. Therefore, we have carried out a study of the binding and interaction with model membranes of a peptide corresponding to segment 1073–1095 of the SARS-CoV S glycoprotein, peptide SARS_L in the presence of different membrane model systems, as well as the structural changes taking place in both the lipid and the peptide induced by the binding of the peptide to the membrane. Our results show that SARS_L strongly partitions into phospholipid membranes and organizes differently in lipid environments, displaying membrane activity modulated by the lipid composition of the membrane. These data would support its role in SARS-CoV mediated membrane fusion and suggest that the region where this peptide resides could be involved in the merging of the viral and target cell membranes.     

The effectiveness of post-contact defenses in a prey with no pre-contact detection

Most empirical and theoretical papers on prey–predator interactions are for animals with long-range detection, animals that can detect and react to predators long before these touch the prey. Heavy-bodied and chemically defended harvestmen (Arachnida, Opiliones) are an exception to this general pattern and rely on contact to detect arthropod predators. We examined the interactions between the Brazilian wandering spider Ctenus ornatus with harvestmen (Mischonyx cuspidatus) or control prey (Gryllus sp. and M. cuspidatus immature, both with soft integuments). Considering a prey–predator system in which fleeing from or reacting to a predator at a distance is not possible, we predicted both a high survival value of near-range defense mechanisms and that mortality would be higher in the absence of such defense mechanisms. We also expected the predator to behave differently when interacting with harvestmen or with a control prey without such defense mechanisms. Our results from laboratory experiments partially matched our predictions: First of all, histological sections showed that the integument of adult harvestmen is thicker than that of immature harvestmen and that of crickets. Adult harvestmen were less preyed upon than the control prey; the heavy armature increases the survival rate but the secretions from the scent glands do not. The predator did behave differently when attacking harvestmen compared to crickets. Despite the large size difference between predator and harvestmen, the protection provided by the armature allowed some of the harvestmen to survive encounters without pre-contact detection, thus greatly reducing the reliance on long-range detection to survive encounters with predators. Harvestmen call for theoretical and empirical work on prey–predator interactions that take into account the possibility that prey may not detect the predator before contact is established.     

Synthesis of Fucosyl-N-Acetylglucosamine Disaccharides by Transfucosylation Using α-l-Fucosidases from Lactobacillus casei

AlfB and AlfC α-l-fucosidases from Lactobacillus casei were used in transglycosylation reactions, and they showed high efficiency in synthesizing fucosyldisaccharides. AlfB and AlfC activities exclusively produced fucosyl-α-1,3-N-acetylglucosamine and fucosyl-α-1,6-N-acetylglucosamine, respectively. The reaction kinetics showed that AlfB can convert 23% p-nitrophenyl-α-l-fucopyranoside into fucosyl-α-1,3-N-acetylglucosamine and AlfC at up to 56% into fucosyl-α-1,6-N-acetylglucosamine.     

nAChR‐induced octopamine release mediates the effect of nicotine on a startle response in Drosophila melanogaster

Biogenic amines (BAs) play a central role in the generation of complex behaviors in vertebrates and invertebrates, including the fly Drosophila melanogaster. The comparative advantages of Drosophila as a genetic model to study the contribution of BAs to behaviors stumble upon the difficulty to access the fly brain to ask relevant physiological questions. For instance, it is not known whether the activation of nicotinic acetylcholine receptors (nAChRs) induces the release of BAs in fly brain, a phenomenon associated to several behaviors in vertebrates. Here, we describe a new preparation to study the efflux of BAs in the adult fly brain by in vitro chronoamperometry. Using this preparation we show that nAChR agonists including nicotine induce a fast, transient, dose‐dependent efflux of endogenous BAs, an effect mediated by α‐bungarotoxin‐sensitive nAChRs. By using different genetic tools we demonstrate that the BA whose efflux is induced by nAChR activation is octopamine (Oct). Furthermore, we show that the impairment of a mechanically induced startle response after nicotine exposure is not observed in flies deficient in Oct transmission. Thus, our data show that the efflux of BAs in Drosophila brain is increased by nAChR activation as in vertebrates, and that then AChR‐induced Oct release could have implications in a nicotine‐induced behavioral response.     

5′‐ectonucleotidase mediates multiple‐drug resistance in glioblastoma multiforme cells

Glioblastoma multiforme (GBM) cells are characterised by their extreme chemoresistance. The activity of multiple‐drug resistance (MDR) transporters that extrude antitumor drugs from cells plays the most important role in this phenomenon. To date, the mechanism controlling the expression and activity of MDR transporters is poorly understood. Activity of the enzyme ecto‐5′‐nucleotidase (CD73) in tumor cells, which hydrolyses AMP to adenosine, has been linked to immunosuppression and prometastatic effects in breast cancer and to the proliferation of glioma cells. In this study, we identify a high expression of CD73 in surgically resected samples of human GBM. In primary cultures of GBM, inhibition of CD73 activity or knocking down its expression by siRNA reversed the MDR phenotype and cell viability was decreased up to 60% on exposure to the antitumoral drug vincristine. This GBM chemosensitization was caused by a decrease in the expression and activity of the multiple drug associated protein 1 (Mrp1), the most important transporter conferring multiple drug resistance in these cells. Using pharmacological modulators, we have recognized the adenosine A₃ receptor subtype in mediation of the chemoresistant phenotype in these cells. In conclusion, we have determined that the activity of CD73 to trigger adenosine signaling sustains chemoresistant phenotype in GBM cells. J. Cell. Physiol. 228: 602–608, 2013. © 2012 Wiley Periodicals, Inc.     

The altitudinal limit of Leptohyphes Eaton, 1882 and Lachlania Hagen, 1868 (Ephemeroptera: Leptohyphidae,Oligoneuriidae) in Ecuadorian Andes streams: searching for mechanisms

We explored mechanisms determining the upper altitudinal limit of ephemeropterans from two different genera: Leptohyphes Eaton, 1882 Eaton, A.E. (1882), ?An Announcement of New Genera of the Ephemeridae?, The Entomologist's Monthly Magazine, 18, 207–208. [Google Scholar] (Leptohyphidae) and Lachlania Hagen, 1868 Hagen, H.A. (1868), ?On Lachlania Abnormis: A New Genus and Species from Cuba Belonging to the Ephemerina?, Proceedings of the Boston Society of Natural History, 11, 372–375. [Google Scholar] (Oligoneuriidae). For this, we (1) surveyed the two taxa in 165 stream sites along a wide altitudinal gradient; (2) sampled benthic fauna at short altitudinal intervals along a stream, from 2780 to 3150 m above sea level; (3) collected adults at the lowest and highest sites; and (4) transplanted nymphs from the lowest to the highest study site in our stream to determine survival over time. Densities of the two taxa declined gradually with altitude and both disappeared between 2950 and 3080 m a.s.l. The upper altitudinal limit in the stream seemed to be most closely related to mean oxygen saturation, temperature, and current velocity. Adults were collected where the nymphs were found, but not at the upstream site where the nymphs were absent, implying limited upstream dispersal of adults and some of the altitudinal constraint lying at the adult stage. Short-term survival of transplanted nymphs was lower than that of controls, suggesting that the distribution was limited at the juvenile stage, and that at least some of the altitudinal constraint is related to the abiotic stream environment.     

Dysregulated molecular pathways in amyotrophic lateral sclerosis–frontotemporal dementia spectrum disorder

Frontotemporal dementia (FTD), the second most common form of dementia in people under 65 years of age, is characterized by progressive atrophy of the frontal and/or temporal lobes. FTD overlaps extensively with the motor neuron disease amyotrophic lateral sclerosis (ALS), especially at the genetic level. Both FTD and ALS can be caused by many mutations in the same set of genes; the most prevalent of these mutations is a GGGGCC repeat expansion in the first intron of C9ORF72. As shown by recent intensive studies, some key cellular pathways are dysregulated in the ALS‐FTD spectrum disorder, including autophagy, nucleocytoplasmic transport, DNA damage repair, pre‐mRNA splicing, stress granule dynamics, and others. These exciting advances reveal the complexity of the pathogenic mechanisms of FTD and ALS and suggest promising molecular targets for future therapeutic interventions in these devastating disorders.     

Cell Adhesion and Proliferation on Sulfonated and Non-Modified Chitosan Films

Three types of chitosan-based films have been prepared and evaluated: a non-modified chitosan film bearing cationizable aliphatic amines and two films made of N-sulfopropyl chitosan derivatives bearing both aliphatic amines and negative sulfonate groups at different ratios. Cell adhesion and proliferation on chitosan films of C2C12 pre-myoblastic cells and B16 cells as tumoral model have been tested. A differential cell behavior has been observed on chitosan films due to their different surface modification. B16 cells have shown lower vinculin expression when cultured on sulfonated chitosan films. This study shows how the interaction among cells and material surface can be modulated by physicochemical characteristics of the biomaterial surface, altering tumoral cell adhesion and proliferation processes.