Total chemical synthesis of sumoylated histone H4 reveals negative biochemical crosstalk with histone ubiquitylation.

An efficient total chemical synthesis of site-specifically sumoylated histone H4 was undertaken to generate homogenously modified mononucleosomes. These were tested as substrates in biochemical assays with the histone H2B-specific ubiquitin ligases Rad6 and Bre1, which revealed the strong inhibition of H2B ubiquitylation by SUMO. This novel negative biochemical crosstalk between SUMO and ubiquitin was also confirmed to exist in human cells.

Determinants of adenine-mutagenesis in diversity-generating retroelements.

Diversity-generating retroelements (DGRs) vary protein sequences to the greatest extent known in the natural world. These elements are encoded by constituents of the human microbiome and the microbial 'dark matter'. Variation occurs through adenine-mutagenesis, in which genetic information in RNA is reverse transcribed faithfully to cDNA for all template bases but adenine. We investigated the determinants of adenine-mutagenesis in the prototypical Bordetella bacteriophage DGR through an in vitro system composed of the reverse transcriptase bRT, Avd protein, and a specific RNA. We found that the catalytic efficiency for correct incorporation during reverse transcription by the bRT-Avd complex was strikingly low for all template bases, with the lowest occurring for adenine. Misincorporation across a template adenine was only somewhat lower in efficiency than correct incorporation. We found that the C6, but not the N1 or C2, purine substituent was a key determinant of adenine-mutagenesis. bRT-Avd was insensitive to the C6 amine of adenine but recognized the C6 carbonyl of guanine. We also identified two bRT amino acids predicted to nonspecifically contact incoming dNTPs, R74 and I181, as promoters of adenine-mutagenesis. Our results suggest that the overall low catalytic efficiency of bRT-Avd is intimately tied to its ability to carry out adenine-mutagenesis.

Polyphenolic content and bactericidal effect of Mexican Citrus limetta and Citrus reticulata.

In this study, total phenolics, total flavonoids, hesperidin and ascorbic acid contents in bagasse, juice and seed of mexican sweet lime (Citrus limetta) and mandarine (Citrus reticulata) were determined at two commercial maturity stages (maturation index), as well as their bactericidal effect on Escherichia coli and Staphylococcus aureus. The results showed that bagasses had the highest total phenolics, total flavonoids, and hesperidin content for both, C. limetta, and C. reticulata; highest ascorbic acid contents were found in C. limetta juice (3.36 ± 0.25 mg g-1 DW) and C. reticulata bagasse (3.83 ± 0.37 mg g-1 DW). All tested extracts showed bacterial growth inhibition at 50 and 800 µg mL-1. Bagasse extracts of both fruits showed the highest inhibitions (>90%) on tested bacteria. Total phenolics, total flavonoids, and hesperidin contents, as well as bactericidal effect increased with maturity. Results indicated that both Mexican citric fruits (C. limetta and C. reticulata) were good sources of antioxidant and bactericidal agents.

Procedimientos actuales para la extracción y purificación de flavonoides cítricos / Current procedures for extraction and purification of citrus flavonoides

En la industria alimenticia, los agentes microbicidas son usados para preservar la calidad y seguridad de los alimentos procesados. Los flavonoides encontrados en extractos cítricos han mostrado capacidad de inhibición del crecimiento celular de un gran grupo de microorganismos infecciosos, por lo tanto, éstos compuestos pueden ser útiles como agentes antivirales, antifúngicos y antibacteriales. Los flavonoides que se pueden encontrar principalmente en varias de las especies cítricas son hesperetina, hesperidina, luteolina, naringenina, naringina, narirutina, neohesperidina, nobiletina y tangeretina. A continuación se resumen los procesos utilizados recientemente para extraer, purificar y analizar los flavonoides principales en frutas cítricas. Ya optimizado el medio de cultivo se procedió a realizar una cinética confirmatoria con base a las condiciones encontradas pero evaluando el crecimiento celular por conteo en cámara de Neubauer y la producción de etanol mediante método enzimático (Procedimiento de ensayo K-ETOH, Megazyme) para confirmar los valores.

In the food industry, antimicrobial agents are used for preserving the quality and safety of processed food. Flavonoids found in citrus extracts inhibit cell growth of a large group of infectious microorganisms, therefore, these compounds may be useful as antiviral, antifungal and antibacterial agents. Hesperetin, hesperidin, luteolin, naringenin, naringin, narirutin, neohesperidin, nobiletin and tangeretin are some of the main flavonoids found in various citrus fruits. The processes used in recent years to extract, purify and analyze typical flavonoids from citrus species are reviewed.

Factores de riesgo para mortalidad por neumonia adquirida en la comunidad en niños hospitalizados menores de cinco años. Instituto Nacional de Salud del Niño / Risk factors for mortality from community-acquired pneumonia in hospitalized children under five. National Institute of Child Health

Introducción: La neumonía adquirida en la comunidad (NAC) constituye la primera causa de mortalidad en niños menores de cinco años a nivel mundial. En nuestro país, a pesar de su gran prevalencia se dispone de poca información respecto a los factores de riesgo para mortalidad en dicha población. Objetivo: Determinar los factores de riesgo para mortalidad en pacientes menores de cinco años con neumonía adquirida en la comunidad, hospitalizados en el Instituto Nacional de Salud del Niño (INSN), Lima-Perú. Material y métodos: Estudio de casos y controles. Se evaluaron 197 historias (63 casos y 134 controles) de pacientes menores de 5 años ingresados con diagnóstico de ingreso de NAC al INSN. Las características epidemiológicas, y clínicas de cada paciente, así como los resultados de exámenes auxiliares fueron evaluados mediante estadística descriptiva y análisis bivariado. Aquellos factores que alcanzaron significancia estadística en este último fueron evaluados mediante regresión logística. Resultados: Mediante el análisis bivariado se encontró significancia estadística respecto a la edad de los pacientes (p <0,001), el antecedente de bajo peso al nacer (p=0,04; OR: 2,79), la falta de alimentación durante el tiempo de enfermedad (p<0,001; OR: 6,2), la saturación de oxígeno (p=0,01; OR: 2,52) Y la severidad de la neumonía (p<0,001). En el análisis multivariado se encontró significancia estadística respecto a la falta de alimentación durante el tiempo de enfermedad (p=0, 008; OR: 4,92) Y la severidad del cuadro, encontrándose dentro de esta última que la categoría de neumonía "Muy severa" es la más relacionada a la mortalidad (p<0,001; OR: 87,17).Conclusiones: La falta de alimentación durante el tiempo de enfermedad y el diagnóstico de ingreso de neumonía muy severa, definida de acuerdo a los parámetros de la OMS, constituyen factores de riesgo para mortalidad por NAC en pacientes menores de 5 años

Introduction: Community-acquired pneumonia (CAP) is the wortdwide leading cause of mortality in children under 5 years old. In our country, des pite its high prevalence there is little information regarding risk factors for mortality in this population. Objective: T o determine risk factors for mortality in patients less than 5 years old with community-acquired pneumonia hospitalized at the Instituto Nacional de Salud del Nino (INSN), Lima-Peru. Materials and Methods: Case-control study. 197 medical historys were evaluated (63 cases and 134 controls) of patients younger than 5 years old hospitalized with admission diagnosis of CAP at the INSN. The epidemiological and clinical data and auxiliary test results were evaluated by descriptive statistics and bivariate analysis. Those factors that were statistically significant in the latter were evaluated using logistic regression. Results: By using bivariate analysis statistical significance was found regarding the age of the patients (p <0.001), history of low birth weight (p = 0.04, OR: 2.79), lack of feeding during the time of iIIness (p <0.001, OR: 6.2), oxygen saturation (p=0, 01; OR: 2, 52) and severity of pneumonia (p <0.001). In multivariate analysis, statistical significance was found regarding the lack of feeding during the time of illness (p = 0.008, OR: 4.92) and the severity of the disease, the latter being found within the category of "very severe" pneumonia, as the most related to mortality (p <0.001, OR: 87.17). Conclusions: The lack of feeding during the time of iIIness and admission diagnosis of very severe pneumonia, defined according to WHO standards, are risk factors for mortality in CAP in patients under 5 years old