RESUMEN
The dopaminergic mesolimbic system plays a key role in mediating the reinforcing properties of ethanol and other drugs of abuse. Ethanol reinforcement and high alcohol drinking behaviour have been suggested to involve the ethanol-induced activation of endogenous opioid systems. Ethanol may alter opioidergic transmission at different levels, including opioid peptide biosynthesis and release, as well as binding to opioid receptors. The aim of this work was to investigate the effects of different ethanol doses on methionine-enkephalin (Met-enk) release from the rat nucleus accumbens (NAcc). Ethanol effects were also studied on Met-enk content in the NAcc, prefrontal cortex (PFC) and caudate-putamen (CP). Met-enk release was studied by microdialysis in Wistar anesthetized rats and peptide concentrations were quantitated by radioimmunoassay. Ethanol was administered by intraperitoneal injection after a 2-h basal release period. Ethanol doses of 0.5, 1 and 2.5 g/kg induced a 2.7-, 4.9- and 3.4-fold increase in Met-enk release from the NAcc. However, ethanol responses followed different kinetics, with earliest effects observed with the highest ethanol dose. In comparison, a 2.5-fold increase in peptide release was produced by 100 mM KCl. Ethanol, at a dose of 2.5 g/kg, induced a significant 66.7% decrease in Met-enk content in the NAcc, as well as a 76.4% reduction in peptide levels in the CP. Lower ethanol doses did not alter Met-enk content in these regions. On the other hand, an ethanol dose of 0.5 g/kg produced a non-significant decrease in Met-enk levels in the PFC. Our results suggest that ethanol-induced changes in enkephalin expression and release in regions of the mesocorticolimbic and nigrostriatal pathways could be involved in ethanol central effects. Released enkephalins by ethanol may modulate the dopaminergic activity of mesolimbic neurons and play a critical role in ethanol reinforcement mechanisms.
Asunto(s)
Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encefalina Metionina/metabolismo , Etanol/administración & dosificación , Neuronas/efectos de los fármacos , Análisis de Varianza , Animales , Dopamina/metabolismo , Relación Dosis-Respuesta a Droga , Inyecciones Intraperitoneales , Masculino , Microdiálisis , Neuronas/metabolismo , Radioinmunoensayo , Ratas , Ratas WistarRESUMEN
Mezcal is an alcoholic beverage obtained from the distillation of fermented juices of cooked Agave spp. plant stalks (agave must), and each region in Mexico with denomination of origin uses defined Agave species to prepare mezcal with unique organoleptic characteristics. During fermentation to produce mezcal in the state of Tamaulipas, not only alcohol-producing yeasts are involved, but also a lactic acid bacterial community that has not been characterized yet. In order to address this lack of knowledge on this traditional Mexican beverage, we performed a DGGE-16S rRNA analysis of the lactic acid bacterial diversity and metabolite accumulation during the fermentation of a typical agave must that is rustically produced in San Carlos County (Tamaulipas, Mexico). The analysis of metabolite production indicated a short but important malolactic fermentation stage not previously described for mezcal. The denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA genes showed a distinctive lactic acid bacterial community composed mainly of Pediococcus parvulus, Lactobacillus brevis, Lactobacillus composti, Lactobacillus parabuchneri, and Lactobacillus plantarum. Some atypical genera such as Weissella and Bacillus were also found in the residual must. Our results suggest that the lactic acid bacteria could strongly be implicated in the organoleptic attributes of this traditional Mexican distilled beverage.
Asunto(s)
Agave/microbiología , Bebidas Alcohólicas/microbiología , Bacillus/aislamiento & purificación , Ácido Láctico/metabolismo , Lactobacillales/aislamiento & purificación , Bacillus/clasificación , Bacillus/genética , Bacillus/metabolismo , Secuencia de Bases , Dermatoglifia del ADN , ADN Ribosómico/análisis , Electroforesis en Gel de Gradiente Desnaturalizante , Fermentación , Microbiología de Alimentos , Lactobacillales/clasificación , Lactobacillales/genética , Lactobacillales/metabolismo , Lactobacillus/clasificación , Lactobacillus/genética , Lactobacillus/aislamiento & purificación , Lactobacillus/metabolismo , Levilactobacillus brevis/clasificación , Levilactobacillus brevis/genética , Levilactobacillus brevis/aislamiento & purificación , Levilactobacillus brevis/metabolismo , Lactobacillus plantarum/clasificación , Lactobacillus plantarum/genética , Lactobacillus plantarum/aislamiento & purificación , Lactobacillus plantarum/metabolismo , México , Pediococcus/clasificación , Pediococcus/genética , Pediococcus/aislamiento & purificación , Pediococcus/metabolismo , Filogenia , Reacción en Cadena de la Polimerasa , ARN Bacteriano/genética , ARN Ribosómico 16S/análisis , Weissella/clasificación , Weissella/genética , Weissella/aislamiento & purificación , Weissella/metabolismoRESUMEN
Native strains of Trichoderma isolated from sorghum and common bean crop soils were investigated to assess their biocontrol potential over the phytopathogenic fungus Macrophomina phaseolina, isolated from diseased plants. The Trichoderma strains were characterized with a polyphasic approach, which combined the analysis of their morphological characteristics, enzymatic activity, macro- and microculture test results, rDNA restriction patterns (AFLP), ITS1-5.8S-ITS2 rDNA sequences, and protein profiles. The integration of these data sets can be used to select new isolates as biological control agents against native fungal phytopathogens. In general, we observed a positive correlation between the secretion of beta-1,3-glucanase and N-acetylhexosaminidase, and the biocontrol capacities of all the Trichoderma isolates. Strains with the best hyperparasitic behavior against M. phaseolina isolated from diseased bean and sorghum were Trichoderma sp. (TCBG-2) and Trichoderma koningiopsis (TCBG-8), respectively.