RESUMEN
BACKGROUND AND PURPOSE: Caffeine (a non-selective adenosine receptor antagonist) prevents memory deficits in aging and Alzheimer's disease, an effect mimicked by adenosine A2 A receptor, but not A1 receptor, antagonists. Hence, we investigated the effects of adenosine receptor agonists and antagonists on memory performance and scopolamine-induced memory impairment in mice. EXPERIMENTAL APPROACH: We determined whether A2 A receptors are necessary for the emergence of memory impairments induced by scopolamine and whether A2 A receptor activation triggers memory deficits in naïve mice, using three tests to assess short-term memory, namely the object recognition task, inhibitory avoidance and modified Y-maze. KEY RESULTS: Scopolamine (1.0 mg·kg(-1) , i.p.) impaired short-term memory performance in all three tests and this scopolamine-induced amnesia was prevented by the A2 A receptor antagonist (SCH 58261, 0.1-1.0 mg·kg(-1) , i.p.) and by the A1 receptor antagonist (DPCPX, 0.2-5.0 mg·kg(-1) , i.p.), except in the modified Y-maze where only SCH58261 was effective. Both antagonists were devoid of effects on memory or locomotion in naïve rats. Notably, the activation of A2 A receptors with CGS 21680 (0.1-0.5 mg·kg(-1) , i.p.) before the training session was sufficient to trigger memory impairment in the three tests in naïve mice, and this effect was prevented by SCH 58261 (1.0 mg·kg(-1) , i.p.). Furthermore, i.c.v. administration of CGS 21680 (50 nmol) also impaired recognition memory in the object recognition task. CONCLUSIONS AND IMPLICATIONS: These results show that A2 A receptors are necessary and sufficient to trigger memory impairment and further suggest that A1 receptors might also be selectively engaged to control the cholinergic-driven memory impairment.
Asunto(s)
Trastornos de la Memoria/fisiopatología , Memoria a Corto Plazo/fisiología , Agonistas del Receptor Purinérgico P1/farmacología , Antagonistas de Receptores Purinérgicos P1/farmacología , Receptor de Adenosina A2A/fisiología , Adenosina/administración & dosificación , Adenosina/análogos & derivados , Adenosina/antagonistas & inhibidores , Adenosina/farmacología , Animales , Reacción de Prevención/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Infusiones Intraventriculares , Locomoción/efectos de los fármacos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Trastornos de la Memoria/inducido químicamente , Memoria a Corto Plazo/efectos de los fármacos , Ratones , Fenetilaminas/administración & dosificación , Fenetilaminas/antagonistas & inhibidores , Fenetilaminas/farmacología , Pirimidinas/farmacología , Receptor de Adenosina A1/fisiología , Reconocimiento en Psicología/efectos de los fármacos , Escopolamina/antagonistas & inhibidores , Escopolamina/farmacología , Triazoles/farmacología , Xantinas/farmacologíaRESUMEN
Butadiene is marketed containing p-tertbutylcatechol (p-TBC), a polymerization inhibitor that should be removed before butadiene utilization in synthetic rubber production. p-TBC can be removed from butadiene by washing with sodium hydroxide (NaOH) solution, producing a wastewater with pH 14, which contains high amounts of p-TBC, a toxic chemical compound. The aim of this work was to develop a treatment process that could reduce the content of p-TBC from the wastewater. Since p-TBC is very soluble in basic, but not in neutral and acid solutions, acidification tests were performed with phosphoric acid (H3PO4) to precipitate p-TBC. Reaction between NaOH and H3PO4 can result in crystallization of large amounts of salt without p-TBC precipitation. Under selected acidifying conditions p-TBC precipitates and the wastewater COD is highly reduced (> 90/o). Chromatographic determinations showed that the precipitated p-TBC could be recovered with 99% purity.
Asunto(s)
Butadienos/química , Catecoles/aislamiento & purificación , Elastómeros/química , Residuos Industriales , Catecoles/análisis , Catecoles/química , Precipitación Química , Concentración de Iones de Hidrógeno , Ácidos Fosfóricos/química , Hidróxido de Sodio/químicaRESUMEN
Use of a continuous microflow submerged microcoil (CSMC) apparatus was compared with the capillary tube (CT) method for measuring the thermal inactivation kinetics of Pseudomonas fluorescens at 61 degrees C for 3 to 29 s. Inocula were continuously pumped through a microbore (< or = 0.0762 cm inside diameter) thin-walled stainless steel capillary tube submerged in a heated oil bath. The heating time was set by changing the flow rate, tube dimensions, or both. With the use of microthermo-couples, the time for the inocula to reach within 1 degree C of the set temperature was <3 s, and shorter than that with capillary tubes or vials. Inactivation curves (61 degrees C) for P. fluorescens prepared by the CSMC method were not different from curves prepared by the CT method, as determined by analysis of variance (P > 0.05). Inactivation of Bacillus cereus spores (105 degrees C) and native microflora found in raw milk (72 degrees C) over heating times of 3 to 42 s were determined by CSMC. CSMC can measure thermal inactivation kinetics of microorganisms efficiently and simply at high temperatures and in short times. Survivors can be enumerated in 1-ml volumes of heat-treated samples, making it useful for determining inactivation kinetics of low numbers of microorganisms, such as those found in high-quality raw milk. Inactivation kinetics were generally more accurately described by the Weibull function (R2 > or = 0.97) than the linear kinetic model.
Asunto(s)
Bacillus cereus/fisiología , Manipulación de Alimentos/instrumentación , Manipulación de Alimentos/métodos , Microbiología de Alimentos , Leche/microbiología , Pseudomonas fluorescens/fisiología , Animales , Bacillus cereus/crecimiento & desarrollo , Calor , Cinética , Pseudomonas fluorescens/crecimiento & desarrollo , Esporas Bacterianas/crecimiento & desarrolloRESUMEN
Postpasteurization addition of CO2 inhibits growth of certain microorganisms in dairy products, but few workers have investigated the effect of CO2 on the thermal inactivation of microorganisms during pasteurization. Concentrations of CO2 ranging from 44 to 58 mM added to raw whole milk significantly (P < 0.05) reduced the number of surviving standard plate count (SPC) organisms in milk heated over the range of 67 to 93 degrees C. A decrease in thermal survival rates (D-values) for Pseudomonas fluorescens R1-232 and Bacillus cereus ATCC 14579 spores in milk was positively correlated with CO2 concentrations (1 to 36 mM). D(50 degrees C)-values for P. fluorescens significantly decreased (P < 0.05) in a linear fashion from 14.4 to 7.2 min. D(89 degrees C)-values for B. cereus spores were significantly (P < 0.05) decreased from 5.56 min in control milk to 5.29 min in milk containing 33 mM CO2. The Weibull function was used as a model to describe the thermal inactivation of P. fluorescens, B. cereus spores, and SPC organisms in raw milk. Nonlinear parameters for the Weibull function were estimated, and survival data fitted to this model had higher R2 values than when fitted to the linear model, further providing support that the thermal inactivation of bacteria does not always follow first-order reaction rate kinetics. These results suggest that CO2 could be used as a processing aid to enhance microbial inactivation during pasteurization.
Asunto(s)
Bacillus cereus/efectos de los fármacos , Dióxido de Carbono/farmacología , Manipulación de Alimentos/métodos , Calor , Leche/microbiología , Pseudomonas fluorescens/efectos de los fármacos , Animales , Bacillus cereus/crecimiento & desarrollo , Microbiología de Alimentos , Cinética , Pseudomonas fluorescens/crecimiento & desarrollo , Esporas BacterianasRESUMEN
Four maternal systems are known to pattern the early Drosophila embryo. The key component of the anterior system is the homeodomain protein Bicoid (Bcd). Bcd needs the contribution of another anterior morphogen, Hunchback (Hb), to function properly: Bcd and Hb synergize to organize anterior development. A molecular mechanism for this synergy has been proposed to involve specific interactions of Bcd and Hb with TATA-binding protein-associated factors (TAFIIs) that are components of the general transcription machinery. Bcd contains three putative activation domains: a glutamine-rich region, which interacts in vitro with TAFII110; an alanine-rich domain, which targets TAFII60; and a C-terminal acidic region, which has an unknown role. We have generated flies carrying bcd transgenes lacking one or several of these domains to test their function in vivo. Surprisingly, a bcd transgene that lacks all three putative activation domains is able to rescue the bcdE1 null phenotype to viability. Moreover, the development of these embryos is not affected by the presence of dominant negative mutations in TAFII110 or TAFII60. This means that the interactions observed in vitro between Bcd and TAFII60 or TAFII110 aid transcriptional activation but are dispensable for normal development.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila , Drosophila/embriología , Proteínas de Homeodominio/metabolismo , Factores Asociados con la Proteína de Unión a TATA , Transactivadores/metabolismo , Factor de Transcripción TFIID , Factores de Transcripción/metabolismo , Animales , Animales Modificados Genéticamente , Tipificación del Cuerpo , Proteínas de Unión al ADN/química , Embrión no Mamífero/fisiología , Femenino , Eliminación de Gen , Impresión Genómica , Proteínas de Homeodominio/química , Proteínas de Homeodominio/genética , Homocigoto , Técnicas In Vitro , Proteínas de Insectos/metabolismo , Recombinación Genética , Transactivadores/química , Transactivadores/genética , Transcripción GenéticaRESUMEN
Mutants from Schizosaccharomyces pombe deficient in the regulation of thiamine-repressible acid phosphatase have been isolated. Mutants expressing derepressed levels of the enzyme in the presence and absence of thiamine map in three genes, tnr1, tnr2 and tnr3. mRNA levels of the pho4 gene (coding for thiamine repressible acid phosphatase) and another thiamine-regulatable gene, thi3 (coding for a thiamine biosynthetic enzyme and corresponding to nmt1) are constitutively synthesized in the mutants. The mutants also exhibit constitutive thiamine transport which is thiamine repressible in wild type. The tnr3 mutants reveal a 10-20-fold higher intracellular thiamine level than tnr1 and tnr2 mutants and wild type. Mutants expressing repressed levels of thiamine-repressible acid phosphatase map in gene thi1. No or little amounts of pho4- and nmt1-specific mRNA can be detected. These mutants are impaired in thiamine uptake and are thiamine auxotrophic due to the inability to synthesize the thiazole moiety of the thiamine molecule. All tested tnr and thi1 alleles are recessive, and thi1 mutations are epistatic over tnr mutations. We assume that the thi1 and tnr genes are involved in thiamine-mediated transcription control.