The role of the TrkB-T1 receptor in the neurotrophin-4/5 antagonism of brain-derived neurotrophic factor on corticostriatal synaptic transmission

This manuscript reviews the function and fundamental characteristics of the neurotrophins and their receptors to introduce the reader to the differential effects exhibited by the neurotrophins;brain-derived neurotrophic factor and neurotrophin 4/5 when acted together after sequential presentation.The neurotrophin 4/5 exhibits an inhibitory action on the modulatory effect of brain-derived neurotrophic factor in corticostriatal synapses when they are administered sequentially(brain-derived neurotrophic factor to neurotrophin 4/5).This inhibitory effect has not been previously documented and is relevant for these neurotrophins as both of them stimulate the TrkB receptor.The additive effect of these neurotrophins is also discussed and occurs when neurotrophin 4/5 exposure is followed by brain-derived neurotrophic factor in a mouse model of striatal degeneration.Occlusive and additive effects of both neurotrophins are accompanied by changes in the expression of the TrkB receptor isoforms,specifically TrkB-T1 and TrkB-FL,as well as differences in phosphorylation levels of the TrkB receptor.The results of the experiments described raise several questions to inquire about the role that TrkB-T1 receptor plays in striatal physiology,as well as the functional relevance of the interaction of brain-derived neurotrophic factor and neurotrophin 4/5 in the brain and more specifically at the striatal circuits in normal as well as pathological conditions.

Ayahuasca:Uses,Phytochemical and Biological Activities

Ayahuasca(caapi,yajé),is a psychoactive brew from the Amazon Basin region of South America traditionally considered a“master plant.”It is prepared as a decoction from Banisteriopsis caapi and Psychotria viridis,which it is thought that it stimulates creative thinking and visual creativity.Native healers of the Orinoco and Amazon basins have used traditionally ayahuasca as a healing tool for multiple purposes,particularly to treat psychological disorders in the patients,with some beneficial effects experimentally and clinically validated.Recently,several syncretic religions,as the“Uniao de Vegetal”(UDV)group in Brazil,have been spread around the world.The use of ayahuasca has been popularized by internet and smart-shops,bringing the psychoactive substance to new highs,emerging new“ayahuasqueros.”Ayahuasca has alkaloids asβ-carbolines and dimethyltryptamines,which inhibit the monoamine oxidase and active the 5-HT_(2A)(5-hydroxytryptamine)receptor,respectively,resulting in hallucinations in the users.Ayahuasca induces a psychedelic change in the anteroposterior coupling of the electrophysiological brain oscillations in humans.Traditional ayahuasca beverage is generating pharmacological,commercial and spiritual interest among the scientific community,government people,and different populations worldwide.The goal of this article is to report about the uses,chemistry and biological activities of ayahuasca.

Ecological-Genetic Studies and Conservation of Endemic <i>Quercus sideroxyla</i>(Trel.) in Central Mexico

This study examines the distribution, ecology and genetic diversity of Quercus sideroxyla Humb. Bonpl, with an emphasis on its conservation on the Natural Protected Area of Sierra Fría in North Central Mexico. Twenty-nine locations were selected, and in each location, one plot of 1500 m2 was established. At every location, we obtained an abundance of Q. sideroxyla and a basal area for each individual tree, including geographical and climatological data. We used the Outlying Mean Index (OMI) to examine whether environmental conditions had a distributional effect on Q. sideroxyla populations and to obtain the static size population structure of the species. For the genetic analysis, we collected 18 adult individuals from each population, four polymorphic loci were used to estimate genetic diversity. Q. sideroxyla abundance was associated with narrow environmental conditions, especially when considering the topographical and meteorological environmental variables. The allelic richness value was 84 alleles (21 privatealleles), and the expected mean heterozygosity was 0.855 ± 0.009. The high vulnerability of the species to changes in the land use at the local scale and to global climatic changes increases the species’ susceptibility to local disappearance.

SAP Expression in Candida albicans Strains Isolated from Mexican Patients with Vaginal Candidosis

To determine the frequency and expression of the ten SAP (secreted aspartyl protease) genes in a group of Candida albicans strains isolated from Mexican women suffering from vaginal candidosis, a group of 264 women (age 18 - 57 years) with vaginal infections, predisposed by diabetes mellitus or contraceptive consumption, were evaluated. C. albicans was identified using PCR to amplify the rRNA internal transcribed spacer regions ITS1 and ITS2. The presence of the SAP genes was determined using conventional PCR, and their expression levels were determined using real-time PCR after the C. albicans strains had been grown in reconstituted human vaginal epithelium (RHVE). C. albicans was identified in the samples from 50 women (18.9%). The genotyping frequencies of the SAP genes were as follows: SAP1, 94%;SAP2, 98%;SAP3, 80%;SAP4, 100%;SAP5, 100%;SAP6, 100%;SAP7, 63%;SAP8, 96%;SAP9, 70%;and SAP10, 88%. The most frequently expressed genes in the strains harboring all of the genes were SAP1, 90%;SAP2, 90%;SAP3, 90%;SAP4, 100%;SAP5, 90%;SAP6, 90%;SAP7, 100%;SAP8, 90%;SAP9, 100%;and SAP10, 100%. SAP genes were expressed in the RHVE, suggesting that the Sap proteins play an important role in the pathogenesis of infection.

Virulence Markers in Staphylococcus aureus Strains Isolated from Hemodialysis Catheters of Mexican Patients

Methicillin-resistant Staphylococcus aureus is an increasingly important cause of nosocomial bacterial infections worldwide. S. aureus is responsible for several pathologies, including skin infections, endocarditis, meningitis, deep-tissue ulcers, and sepsis. S. aureus biofilm formation on catheters and other medical devices is a major post-operative concern, because biofilms are often the source of persistent and difficult to treat bacterial infections. While catheter-related S. aureus infections have been reported, the strains responsible for these infections have not been genetically characterized. We genetically characterized S. aureus strains isolated from hemodialysis catheters in Mexican patients. The frequency of 35 genes coding for adhesins, toxins, and other virulence-associated products in the 55 isolated S. aureus strains was determined using PCR, while real-time PCR was used to examine the level of gene expression. Of the 55 S. aureus strains isolated from 109 patients, 45 (81.8%) were determined to be methicillin-resistant. The icaA, rbf, sarA, and agr genes are involved in biofilm formation and bacterial dispersion and were detected in 96.3%, 40.0%, 74.5%, and 100% of S. aureus strains, respectively, and 70.9% of the strains formed a detectable biofilm. Interestingly, 67.2% of the strains contained the icaA, agr, spa, clfA, sdrC, sdrD, sdrE, seg, seh, and sei genes, suggesting that this gene combination is important for successful catheter colonization. The results of this study provide significant insight into the virulence gene make-up of catheter-colonizing S. aureus strains, and will assist in developing a more targeted treatment approach for persistent S. aureus biofilm contamination of medical devices.