Vascular O-GlcNAcylation augments reactivity to constrictor stimuli by prolonging phosphorylated levels of the myosin light chain

O-GlcNAcylation is a modification that alters the function of numerous proteins. We hypothesized that augmented O-GlcNAcylation levels enhance myosin light chain kinase (MLCK) and reduce myosin light chain phosphatase (MLCP) activity, leading to increased vascular contractile responsiveness. The vascular responses were measured by isometric force displacement. Thoracic aorta and vascular smooth muscle cells (VSMCs) from rats were incubated with vehicle or with PugNAc, which increases O-GlcNAcylation. In addition, we determined whether proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation. PugNAc enhanced phenylephrine (PE) responses in rat aortas (maximal effect, 14.2±2 vs 7.9±1 mN for vehicle, n=7). Treatment with an MLCP inhibitor (calyculin A) augmented vascular responses to PE (13.4±2 mN) and abolished the differences in PE-response between the groups. The effect of PugNAc was not observed when vessels were preincubated with ML-9, an MLCK inhibitor (7.3±2 vs 7.5±2 mN for vehicle, n=5). Furthermore, our data showed that differences in the PE-induced contractile response between the groups were abolished by the activator of AMP-activated protein kinase (AICAR; 6.1±2 vs 7.4±2 mN for vehicle, n=5). PugNAc increased phosphorylation of myosin phosphatase target subunit 1 (MYPT-1) and protein kinase C-potentiated inhibitor protein of 17 kDa (CPI-17), which are involved in RhoA/Rho-kinase-mediated inhibition of myosin phosphatase activity. PugNAc incubation produced a time-dependent increase in vascular phosphorylation of myosin light chain and decreased phosphorylation levels of AMP-activated protein kinase, which decreased the affinity of MLCK for Ca2+/calmodulin. Our data suggest that proteins that play an important role in the regulation of MLCK and MLCP activity are directly affected by O-GlcNAcylation, favoring vascular contraction.

Aceptabilidad de sopas deshidratadas de leguminosas adicionadas de realzadores del sabor (UMAMI) / Acceptability of dehydrated legume soups with the addition of flavor enhancers (UMAMI)

The enhancer effect of glutamate monosodium (MSG) flavor was evaluated and its synergistic action with 5'-ribonucleotides: ionone rib nucleotides 5'-monophosphate (IMP) and guano sine monophosphate (GMP) in dehydrated soups consisting of lentils and peas. Four formulations were developed for both soups: the first was the target with the original level of MSG, the following had different concentrations and mixtures of these enhancers (6 percent MSG; 6 percent MSG and 0.26 percent IMP; 0.6 MSG and 0.12 percent IMP-GMP). A five-.point Graphic Hedonic Scale test was used, where 1 represented the most upset face and 5 represented the happiest face. The most accepted soup was selected by thirty elderly adults. The lentils soup with 0,6 MSG and 0J2 percent IMP-GMP and the pea's soup with 6 percent MSG and 0.26 percent IMP obtained the greatest level of acceptance. So, the effectiveness of the synergistic action between the MSG and 5'-ribonucleotides was demonstrated, because they can improve the acceptance of the evaluated formulation.

Se evaluó el efecto realzador del sabor del glutamato monosódico (GMS) y su acción sinergista con 5'-ribonucleótidos: inosinato monofosfato (IMP) y guanilato monofosfato (GMP), cuando se adicionaron a sopas deshidratadas de lentejas y arvejas. Se elaboraron 4 formulaciones para cada sopa, la primera formulación correspondió al control con su nivel de GMS original, las siguientes formulaciones contaron con distintas concentraciones y mezclas de estos realzadores (6 por ciento GMS; 6 por ciento GMS mas 0,26 por ciento IMP y 0,6 GMS mas 0,12 por ciento IMP-GMP). Se utilizó la evaluación sensorial de Escala Hedónica Gráfica, con una escala de 1 al 5, donde 1: representa "la carita más disgustada" y 5: "la más feliz". Treinta adultos mayores determinaron la formulación más aceptada. La sopa de lentejas con 6 por ciento de GMS mas 0,12 por ciento de IMP-GMP fue la que tuvo mayor aceptación, mientras que para la sopa de arvejas fue aquella que contenía 6 por ciento de GMS más 0,26 por ciento de IMP. Por tanto, se pudo demostrar la efectividad de la acción sinergista entre el GMS y los 5'-ribonucleótidos, al mejorar las aceptación de las formulaciones evaluadas.

Efecto sinergistico y cuantificación de los 5-ribonucleótidos en una sopa de pollo / Synergistic effect and quantification of 5´-ribonucleótidos in the chicken soup

La normativa nacional e internacional permite adicionar a las mezclas deshidratadas para caldos y sopas resaltadores del sabor tales como glutamato monosódico (GMS) y los ácidos inosínico y guanílico o sus sales fosfatadas (IMF y GMF, respectivamente), solos o combinados para lograr un efecto sinergístico. Los objetivos de este estudio fueron: 1) determinar mediante un panel sensorial, el efecto sinergístico en el sabor de una sopa de pollo deshidratada cuando se usa mezcla de resaltadores y 2) cuantificar los 5-ribonucleótidos en dicha matriz. La intensidad del sabor a pollo se determinó empleando un panel de 6 personas previamente entrenadas. Los 5-ribonucleótidos se cuantificaron empleando HPLC. Los resultados con el panel entrenado comprobaron que la combinación utilizada de GMS, IMF y GMF potencia significativamente (p<0,05) el sabor de la sopa de pollo deshidratada. El análisis químico de los 5´-ribonucleótidos reflejó un porcentaje de recuperación de 93,6 por ciento para GMF y 90,5 por ciento para IMF

Proteins released from vaccinia cores are probably not involved in protein synthesis inhibition in vitro

It is known that vaccinia core proteins are released into the supernatant fraction when cores are incubated under appropriate conditions. When prepared in the absence of viral transcription this fraction inhibits in vitro protein synthesis. We show here that after incubation, the cores loose the capability to inhibit protein synthesis. Furthermore, we show that no inhibition of translation is observed with supernatant fractions prepared from transcribing cores. SDS-PAGE analysis of the supernatantt fraction of cores obtained in the presence and absence of viral transcription indicated that their protein composiition is similar and approximately 17 peptides are released from the cores and that 4 are phosphorylated. We conclude that the proteins associated with vaccinia cores and released in the presence of ribonucleotides are not involved in protein synthesis inhibition