Bases estructurales del mecanismo de reconocimiento y fosfotransferencia en los sistemas de señalización de dos componentes

Póster original presentado XXVII Congreso de la SEBBM, Sociedad Española de Bioquímica y Biología Molecular, celebrado en Lleida, 12-15 de septiembre, 2004.Los sistemas de dos componentes son el mecanismo principal de transducción de señal en microorganismos. Un sistema paradigmático se compone de dos proteínas: una histidina quinasa (HK) y un regulador de la respuesta (RR). El mecanismo de transducción de señal implica al menos tres reacciones (ver esquema): 1) Autofosforilación: la llegada de un estímulo al dominio extracelular sensor de la HK, induce la fosforilación en un residuo de His conservado en el dominio de dimerización (DHp) por parte del dominio de unión de ATP (CA). 2) Fosfotransferencia: este grupo fosforilo es transferido desde la His a un residuo de Asp del dominio regulador del correspondiente RR. 3) Defosforilación: el RR pierde el grupo fosforilo espontáneamente o mediado por la HK. El estado de fosforilación del dominio regulador en RR regula la actividad de su dominio efector, que es habitualmente un factor de transcripción.Financiado por la ayuda BIO2002-03709 del Ministerio de Ciencia y Tecnología. P. casino es becaria FPI del Ministerio de ciencia y TecnologíaPeer reviewe

Biological treatment of solid wastes from the tobacco industry for enzyme production

Aiming at the production of enzymes using solid wastes from the tobacco industry, the solid fermentation kinetics of Aspergillus niger and Aspergillus terreus using waste of dark tobacco and Virginia tobacco as substrate were characterized. The efficiency of the fermentation process was evaluated by determining the enzymatic activity of the three enzymes that constitute the cellulose enzymatic system (CMCase, PFase and Xylanase). The results obtained led to the establishment of the best initial conditions of fermentation and the selection of the most efficient microorganism for enzyme production. The best results were obtained with Aspergillus terreus for both tobacco residues. In the case of black tobacco, the best incubation temperature was 31 ºC for the enzymes CMCase and Xylanase and 36 ºC for the PFase and initial pH 5.5 for the three enzymes. For the Virginia tobacco, the best incubation temperature and initial pH are the same for the three enzymes, 36 ºC and 5.5 respectively. The biological activity of the fermented tobacco residues was evaluated being the highest rate of inhibition of microbial growth – 72% - obtained with the residue of Virginia tobacco treated with Aspergillus niger

Estrogens promote misfolded proinsulin degradation to protect insulin production and delay diabetes

Summary: Conjugated estrogens (CE) delay the onset of type 2 diabetes (T2D) in postmenopausal women, but the mechanism is unclear. In T2D, the endoplasmic reticulum (ER) fails to promote proinsulin folding and, in failing to do so, promotes ER stress and β cell dysfunction. We show that CE prevent insulin-deficient diabetes in male and in female Akita mice using a model of misfolded proinsulin. CE stabilize the ER-associated protein degradation (ERAD) system and promote misfolded proinsulin proteasomal degradation. This involves activation of nuclear and membrane estrogen receptor-α (ERα), promoting transcriptional repression and proteasomal degradation of the ubiquitin-conjugating enzyme and ERAD degrader, UBC6e. The selective ERα modulator bazedoxifene mimics CE protection of β cells in females but not in males. : Estrogens prevent diabetes in women, but the mechanism is poorly understood. Xu et al. report that estrogens activate the endoplasmic-reticulum-associated protein degradation pathway, which promotes misfolded proinsulin degradation, suppresses endoplasmic reticulum stress, and protects insulin secretion in mice and in human pancreatic β cells. Keywords: estrogens, beta cell, islet, endoplasmic reticulum stress, proinsulin misfolding, diabetes, bazedoxifene, sex dimorphism, ERAD, SER

The use of a silicone-based biomembrane for microaerobic H2S removal from biogas

A lab-scale bio-membrane unit was developed to improve H2S removal from biogas through microaeration. Biomembrane separated biogas from air and consisted of a silicone tube covered by microaerobic biofilm. This setup allowed efficient H2S removal while minimizing biogas contamination with oxygen and nitrogen. The transport and removal of H2S, N-2, O-2, CH4 and CO2 through bare membrane, wet membrane and biomembrane was investigated. Membrane allowed the transfer of gases through it as long as there was enough driving force to induce it. H2S concentration in biogas decreased much faster with the biomembrane. The permeation of gases through the membranes decreased in order: H2S > CO2 > CH4 > O-2 > N-2. H2S removal efficiency of more than 99% was observed during the continuous experiment. Light yellow deposits on the membrane indicated the possible elemental sulfur formation due to biological oxidation of H2S. Thiobacillus thioparus was detected by FISH and PCR-DGGE

Patrones de producción y consumo responsable: La carrera por el logro de los Objetivos de Desarrollo Sostenible (ODS) en mercados emergentes

Since the end of the 20th century, the role of private multinational enterprises (MNEs) has been recognized as critical in implementing increased sustainable production and consumption atterns. Particularly after the creation of the Sustainable Development Goals (SDGs) and the Agenda 2030, this role has increased. In this sense, this paper aims to analyze the measures and actions taken by companies in their contribution to the achievement of the SDG 12. Through the identification of more than 52 metrics in sustainability reports of 854 firms, findings suggest that direct greenhouse gas emissions and indirect greenhouse gas emissions are the most often reported corporate metrics to measure their impact on specific SDGs. This reveals the importance of sustainability actions in emerging market firms as a mechanism to gain legitimacy when operating in foreign markets and as an opportunity to create more sustainable production models.Desde finales del siglo XX, se ha reconocido que el papel de las empresas multinacionales (EMN) privadas es fundamental en el proceso de implementación de patrones de producción y consumo más sostenibles. Especialmente, tras la creación de los Objetivos de Desarrollo Sostenible (ODS) y la Agenda 2030, este papel ha aumentado. En este sentido, este trabajo tiene como objetivo analizar las medidas y acciones tomadas por las empresas en su contribución al logro del ODS 12. Mediante la identificación de más de 52 métricas en los informes de sostenibilidad de 854 empresas, los hallazgos sugieren que las emisiones directas de gases de efecto invernadero y las emisiones indirectas de gases de efecto invernadero son las métricas corporativas con más información para medir su impacto en ODS específicos. Esto revela la importancia de las acciones de sostenibilidad en las empresas de mercados emergentes como mecanismo para ganar legitimidad al operar en mercados externos y como oportunidad para la creación de modelos de producción más sostenibles

Mechanism of the negative inotropic effect of naringin in mouse heart [Mecanismo del efecto inotrópico negativo de la naringina en el corazón de ratón]

Abstract Resumen Context: Naringin (NRG) is the major flavonoid (flavanone glycoside) in grapefruit juice. Its biological activity has been only partially characterized and little is known about the mechanism of the negative inotropic action of this flavonoid. Aims: To evaluate the effects of NRG on the surface electrogram (ECG) and the force of contraction (FC) of mice hearts as well as on the sodium (INa), calcium (ICaL) and Na + -Ca 2+ exchange (INaCaX) currents of enzymatically isolated mouse ventricular cardiomyocytes. Methods: ECG and FC were recorded on mouse hearts perfused in a Langendorff column. Ventricular cardiomyocytes were enzimatically dissociated and ionic currents recorded with the patch-clamp technique. Results: NRG increased RR interval and shortened corrected QT only at high concentrations (30-100 µM). However, at a fixed heart rate, it decreased FC with an IC50 of 0.4 µM. NRG reduced INa with an IC50 of 0.07 µM but with a maximal inhibition of 60 %. NRG also depressed ICaL with an IC50 of 0.013 µM and increased its fast inactivation time constant. The effects on ICaL were not voltage-dependent. INaCaX was not affected by NRG. Conclusions: Our results indicate that NRG exerts a negative inotropic effect in mice hearts that could be explained by a decrease in INa and ICaL. These actions should be taken into account when considering this molecule either as a dietetic supplement or as a template to develop therapeutic agents for human diseases. Contexto: La naringina (NRG) es el principal flavonoide (glicósido de flavanona) en el jugo de toronja. Su actividad biológica ha sido solo parcialmente caracterizada y poco se conoce acerca del mecanismo de la acción inotrópica negativa de este flavonoide. Objetivos: Evaluar los efectos de la NRG sobre el electrograma de superficie (ECG) y la fuerza de contracción (FC) de corazones de ratón, así como sobre las corrientes de sodio (INa), calcio (ICaL) y del intercambiador Na + -Ca 2+ (INaCaX) en cardiomiocitos ventriculares de ratón, aislados enzimáticamente. Métodos: El ECG y la FC se registraron en corazones de ratón perfundidos en una columna de Langendorff. Los cardiomiocitos ventriculares se disociaron enzimáticamente y las corrientes iónicas se registraron con la técnica de patch-clamp. Resultados: La NRG incrementó el intervalo RR intervalo y acortó el QT solo a altas concentraciones (30-100 µM). No obstante, a frecuencia cardíaca fija, disminuyó la FC con un IC50 de 0.4 µM. La NRG redujo INa con un IC50 de 0.07 µM pero con una máxima inhibición de 60 %. La NRG también redujo ICaL con un IC50 de 0.013 µM e incrementó su constante de inactivación rápida. Los efectos sobre ICaL no fueron dependientes del potencial. La INaCaX no fue afectada por la NRG. Conclusiones: Nuestros resultados indican que la NRG ejerce un efecto inotrópico negativo en corazones de ratón que puede ser explicado por una reducción en INa e ICaL. Esas acciones deben ser tomadas en cuenta al considerar a esta molécula como suplemento dietético o como plantilla para desarrollar nuevos agentes terapéuticos para tratar las enfermedades en humanos

Chemistry of a Nitrosyl Ligand ¿:¿-Bridging a Ditungsten Center: rearrangement and N–O Bond cleavage reactions

The novel nitrosyl-bridged complex [W2Cp2(μ-PtBu2)(μ-κ:η-NO)(CO)(NO)](BAr4) [Ar = 3,5-C6H3(CF3)2] was prepared in a multistep procedure starting from the hydride [W2Cp2(μ-H)(μ-PtBu2)(CO)4] and involving the new complexes [W2Cp2(μ-PtBu2)(CO)4](BF4), [W2Cp2(μ-PtBu2)(CO)2(NO)2](BAr4), and [W2(μ-κ:η5-C5H4)Cp(μ-PtBu2)(CO)(NO)2] as intermediates, which follow from reactions with HBF4·OEt2, NO, and Me3NO·2H2O, respectively. The nitrosyl-bridged cation easily added chloride upon reaction with [N(PPh3)2]Cl, with concomitant NO rearrangement into the terminal coordination mode, to give [W2ClCp2(μ-PtBu2)(CO)(NO)2], and underwent N–O and W–W bond cleavages upon the addition of CNtBu to give the mononuclear phosphinoimido complex [WCp(NPtBu2)(CNtBu)2](BAr4). Another N–O bond cleavage was induced upon photochemical decarbonylation at 243 K, which gave the oxo- and phosphinito-bridged nitrido complex [W2Cp2(N)(μ-O)(μ-OPtBu2)(NO)](BAr4), likely resulting from a N–O bond cleavage step following decarbonylation

Joint effect of physical activity and sedentary behaviour on cardiovascular risk factors in Chilean adults

Background: To investigate the associations between combined categories of moderate-to-vigorous physical activity (MVPA) and sedentary behaviour (SB) with markers of adiposity and cardiovascular risk in adults. Methods: Overall, 5040 participants (mean age 46.4 years and 59.3% women) from the cross-sectional Chilean National Health Survey 2009–2010 were included in this study. MVPA and SB were measured using the Global Physical Activity questionnaire. Four categories were computed using MVPA- and SB-specific cut-offs (‘High-SB & Active’, ‘Low-SB & Active’, ‘High-SB & Inactive’ and ‘Low-SB & Inactive’). Results: Compared to the reference group (‘High-SB & Inactive’), those in ‘High-SB & Active’ and ‘Low-SB & Active’ were less likely to have an obese BMI (OR: 0.67 [0.54; 0.85], P = 0.0001 and 0.74 [0.59; 0.92] P = 0.0007, respectively) and less likely to have metabolic syndrome (OR: 0.63 [0.49; 0.82], P < 0.0001 and 0.72 [0.57; 0.91], P = 0.007), central obesity (OR: 0.79 [0.65; 0.96], P = 0.016 and 0.71 [0.59; 0.84], P < 0.0001), diabetes (OR: 0.45 [0.35; 0.59], P < 0.0001 and 0.44 [0.34; 0.56], P < 0.0001) and hypertension (OR: 0.52 [0.43; 0.63], P < 0.0001 and 0.60 [0.50; 0.72], P < 0.0001), respectively. Conclusions: Being physically active and spending less time in SBs was associated with lower adiposity and improvements in cardiovascular risk factors

Genome-Wide Evaluation of Histone Methylation Changes Associated with Leaf Senescence in Arabidopsis

Leaf senescence is the orderly dismantling of older tissue that allows recycling of nutrients to developing portions of the plant and is accompanied by major changes in gene expression. Histone modifications correlate to levels of gene expression, and this study utilizes ChIP-seq to classify activating H3K4me3 and silencing H3K27me3 marks on a genome-wide scale for soil-grown mature and naturally senescent Arabidopsis leaves. ChIPnorm was used to normalize data sets and identify genomic regions with significant differences in the two histone methylation patterns, and the differences were correlated to changes in gene expression. Genes that showed an increase in the H3K4me3 mark in older leaves were senescence up-regulated, while genes that showed a decrease in the H3K4me3 mark in the older leaves were senescence down-regulated. For the H3K27me3 modification, genes that lost the H3K27me3 mark in older tissue were senescence up-regulated. Only a small number of genes gained the H3K27me3 mark, and these were senescence down-regulated. Approximately 50% of senescence up-regulated genes lacked the H3K4me3 mark in both mature and senescent leaf tissue. Two of these genes, SAG12 and At1g73220, display strong senescence up-regulation without the activating H3K4me3 histone modification. This study provides an initial epigenetic framework for the developmental transition into senescence

Monocyte populations as markers of response to adalimumab plus MTX in rheumatoid arthritis

INTRODUCTION: The treatment of rheumatoid arthritis (RA) patients with anti-tumor necrosis factor alpha (TNFα) biological drugs has dramatically improved the prognosis of these patients. However, a third of the treated patients do not respond to this therapy. Thus, the search for biomarkers of clinical response to these agents is currently highly active. Our aim is to analyze the number and distribution of circulating monocytes, and of their CD14(+high)CD16(-), CD14(+high)CD16(+ )and CD14(+low)CD16(+ )subsets in methotrexate (MTX) non-responder patients with RA, and to determine their value in predicting the clinical response to adalimumab plus MTX treatment. METHODS: This prospective work investigated the number of circulating monocytes, and of their CD14(+high)CD16(-), CD14(+high)CD16(+ )and CD14(+low)CD16(+ )subsets, in 35 MTX non-responder patients with RA before and after three and six months of anti-TNFα treatment using multiparametric flow cytometry. The number of circulating monocytes in an age- and sex-matched healthy population was monitored as a control. RESULTS: Non-responder patients with RA show an increased number of monocytes and of their CD14(+high)CD16(-), CD14(+high)CD16(+ )and CD14(+low)CD16(+ )subsets after three months of adalimumab plus MTX treatment that remained significantly increased at six months. In contrast, significant normalization of the numbers of circulating monocytes was found in responders at three months of adalimumab plus MTX treatment that lasts up to six months. CX3CR1 expression is increased in monocytes in non-responders. At three months of anti-TNFα treatment the number of circulating monocytes and their subsets was associated with at least 80% sensitivity, 84% specificity and an 86% positive predictive value (PPV) in terms of discriminating between eventual early responders and non-responders. CONCLUSIONS: The absolute number of circulating monocytes and of their CD14(+high)CD16(-), CD14(+high)CD16(+ )and CD14(+low)CD16(+ )subsets at three months of adalimumab plus MTX treatment, have a predictive value (with high specificity and sensitivity) in terms of the clinical response after six months of anti-TNFα treatment in patients with RA