Producción de fructanos utilizando extractos enzimáticos de Gluconacetobacter diazotrophicus

Los fructanos poseen un particular interés industrial por sus excelentes propiedades biológicas. Son considerados compuestos prebióticos reconocidos por la FDA (Food and Drug Administration – U.S), son utilizados como componentes de alimentos funcionales. Dentro de sus propiedades biológicas se puede destacar que son edulcorantes de bajas calorías, estimulan el crecimiento de bifidobacterias, también contribuyen a la prevención del cáncer de colon y a la reducción de los niveles séricos de colesterol, fosfolipidos y triglicéridos. La producción comercial de fructanos a partir de sacarosa involucra enzimas de origen bacteriano o fungico. El requerimiento de enzimas más eficientes con una alta actividad y estabilidad enzimática, ha atrapado el interés de los biotecnólogos y microbiólogos. Gluconacetobacter diazotrophicus secreta, constitutivamente una levansacarasa (LsdA) que hidroliza la sacarosa produciendo glucosa libre y fructanos de bajo peso molecular (FOS) y alto peso molecular (levanos). En este trabajo hemos discutido la capacidad de diferentes sobrenadantes derivados del crecimiento de G. diazotrophicus de producir fructanos por medio de incubaciones, estudiando diferentes condiciones de incubación. G. diazotrophicus PAL 5 fue crecido a 30 °C, en medio LGI suplementado con 1,5 g/l de extracto de levadura y 1,5 g/l de triptona utilizando sacarosa o glicerol como fuente de carbono. Luego de 10 días de crecimiento, los cultivos fueron centrifugados a 16000g durante 30 minutos. Los sobrenadantes obtenidos fueron incubados con una solución de sacarosa en buffer acético/acetato 0,1 M, pH 5,2. Las condiciones estudiadas fueron: 1- relación enzima/sustrato; 2- temperatura de incubación (30, 40 y 50 °C); 3- concentración de sacarosa en la mezcla de incubación (100, 300 y 700 g/l). La producción de fructanos fue seguida durante 7 días. Los levanos fueron cuantificados por la precipitación de estos polisacáridos adicionando 2 volúmenes de etanol obteniendo peso seco del precipitado. Por su parte los FOS fueron testeados por cromatografía en capa delgada (TLC). La glucosa remanente fue cuantificada por un kit enzimático comercial. Los sobrenadantes derivados de medios con sacarosa muestran una actividad enzimática LsdA menor que los sobrenadantes derivados de medios con glicerol, sin embargo la producción de levanos con sobrenadantes de medios con sacarosa es mayor que los sobrenadantes de medios con glicerol. La producción de levanos fue observada en todas las condiciones testeadas incrementándose con el tiempo de incubación y con la temperatura. La producción de FOS fue detectada en todas las condiciones, después de las 24 horas de incubación, produciéndose principalmente 1-kestosa. Bajas concentraciones de sacarosa en la mezcla de incubación favorecen la hidrólisis de sacarosa. La alta concentración de sacarosa en la mezcla de incubación favorece la producción de fructanos de bajo peso molecular.Centro de Investigación y Desarrollo en Fermentaciones Industriale

Difference in the expression of IL-9 and IL-17 correlates with different histological pattern of vascular wall injury in giant cell arteritis

OBJECTIVE: GCA is a large- and medium-vessel arteritis characterized by a range of histological patterns of vascular wall injury. The aim of this study was to immunologically characterize the various histological patterns of GCA. METHODS: Thirty-five consecutive patients with biopsy-proven GCA and 15 normal controls were studied. IL-8, IL-9, IL-9R, IL-17, IL-4, TGF-β and thymic stromal lymphopoietin expression was evaluated by RT-PCR and immunohistochemistry on artery biopsy specimens. Confocal microscopy was used to characterize the phenotypes of IL-9-producing and IL-9R-expressing cells. Five additional patients who had received prednisone when the temporal artery biopsy was performed were also enrolled to evaluate the effect of glucocorticoids on IL-9 and IL-17 expression. RESULTS: IL-17 overexpression was observed mainly in arteries with transmural inflammation and vasa vasorum vasculitis. IL-9 overexpression and Th9 polarization predominated in arteries with transmural inflammation and small-vessel vasculitis. The tissue expression of both IL-9 and IL-17 was correlated with the intensity of the systemic inflammatory response. IL-4, TGF-β and thymic stromal lymphopoietin, which are involved in the differentiation of Th9 cells, were overexpressed in arteries with transmural inflammation and small-vessel vasculitis. IL-9R was also overexpressed in GCA arteries with transmural inflammation and was accompanied by increased expression of IL-8. CONCLUSION: Herein we provide the first evidence that distinct populations of potentially autoreactive T cells, expressing different cytokines (Th17 vs Th9), characterize patients with particular histological subsets of GCA and may thus contribute to the heterogeneity of tissue lesions observed in these patients

Falta de respuesta a la inoculación de Poroto Alubia con cepas de Rhizobium phaseoli en el Noroeste Argentino

p.263-270El poroto tipo alubia es uno de los cultivos de secano más importantes del Noroeste Argentino. En este cultivo no es usual la práctica de la inoculación. Debido a este hecho es que se realizó el siguiente estudio para evaluar el comportamiento de 4 cepas de Rhizobium phaseoli frente a esta leguminosa. Además se evaluó la competencia por los sitios de infección nodular entre las cepas introducidas y las autóctonas. Las experiencias se realizaron en 2 etapas: a) en cámara de clima controlado y b) a campo (Cerrillos, Salta). El ensayo a) mostró que las Cepas F 45, F 48 y 492 establecen una eficiente simbiosis. La cepa 4012, si bien fue infectiva, fue ineficiente en la fijación de nitrógeno. Las cepas F 48 y F 45 formaron los mayores porcentajes de nodulos y este valor varió con la presencia de nitrato de potasio en las jarras. En el ensayo a campo no se obtuvo respuesta a la inoculación y la nodulación obtenida fue muy baja. Las cepas introducidas formaron más del 80 por ciento de los nodulos frente a las cepas autóctonas, siendo la F 45 la más competitiva por los sitios de infección

Increased expression of interleukin-22 in patients with giant cell arteritis

GCA is characterized by arterial remodelling driven by inflammation. IL-22 is an attractive cytokine which acts at the crosstalk between immune and stromal cells. We hypothesized that IL-22 might be induced in GCA and might be involved in disease pathogenesis

Ascitis quilosa y síndrome de maltrato infantil

La ascitis quilosa (AQ) es una entidad rara asociada a patología del sistema linfático. El primer caso pediátrico fue reportado por Morton en 1.683 en un paciente con tuberculosis. Puede producirse por una malformación linfática congénita, una obstrucción o trauma. La etiología traumática, incluido el síndrome de maltrato infantil (SMI) representa alrededor del 20% (2). Se debe a la disrupción de los linfáticos mesentéricos con acumulación de fluído quiloso en la cavidad peritoneal. Su manejo es controvertido en razón de la experiencia limitada. En éste artículo presentamos un niño con AQ y antecedentes de maltrato que evolucionó favorablemente con soporte nutricional parenteral asociado a octreotido de somatostatina

A consolidated analysis of the physiologic and molecular responses induced under acid stress in the legume-symbiont model-soil bacterium <i>Sinorhizobium meliloti</i>

Abiotic stresses in general and extracellular acidity in particular disturb and limit nitrogen-fixing symbioses between rhizobia and their host legumes. Except for valuable molecular-biological studies on different rhizobia, no consolidated models have been formulated to describe the central physiologic changes that occur in acid-stressed bacteria. We present here an integrated analysis entailing the main cultural, metabolic, and molecular responses of the model bacterium Sinorhizobium meliloti growing under controlled acid stress in a chemostat. A stepwise extracellular acidification of the culture medium had indicated that S. meliloti stopped growing at ca. pH 6.0-6.1. Under such stress the rhizobia increased the O2 consumption per cell by more than 5-fold. This phenotype, together with an increase in the transcripts for several membrane cytochromes, entails a higher aerobic-respiration rate in the acid-stressed rhizobia. Multivariate analysis of global metabolome data served to unequivocally correlate specific-metabolite profiles with the extracellular pH, showing that at low pH the pentose-phosphate pathway exhibited increases in several transcripts, enzymes, and metabolites. Further analyses should be focused on the time course of the observed changes, its associated intracellular signaling, and on the comparison with the changes that operate during the sub lethal acid-adaptive response (ATR) in rhizobia.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Fermentaciones IndustrialesInstituto de Biotecnologia y Biologia Molecula

Analysis of the common genetic component of large-vessel vasculitides through a meta-Immunochip strategy.

Giant cell arteritis (GCA) and Takayasu’s arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P = 7.54E-07; ORGCA = 1.19, ORTAK = 1.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA = 5.52E-04, ORGCA = 1.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus

[Disease activity assessment in large vessel vasculitis]

Disease activity assessment in large vessel vasculitis (LVV) is often challenging for physicians. In this study, we compared the assessment of disease activity based on inflammatory markers, clinical indices (Indian Takayasu Activity Score [ITAS] and the Kerr/National Institute of Health indices [Kerr/NIH]), and 18F-Fluorodesossiglucose (FGD) vascular uptake at positron emission tomography (Pet). We found that Pet results did not statistically correlate with the clinical indices ITAS and Kerr/NIH, because FDG uptake was increased (grade&gt;2 on a 0-3 scale in at least one evaluated vascular segment) in many patients with inactive disease according to clinical and laboratory parameters (i.e., negative ITAS and Kerr/NIH indices as well as normal erythrocyte sedimentation rate (ESR) and C-reactive protein (PCR)). Similarly, interleukin- 6 and its soluble receptor did not statistically correlate with disease activity. In contrast, clinical indices showed a significant correlation between each other and with inflammatory markers (VES and PCR). These data suggest that while clinical indices and inflammatory markers may be useful to assess disease activity, Pet may be more sensitive

Evidence of association of the NLRP1 gene with giant cell arteritis

Recent studies have focused attention on the involvement of NLRP1 to confer susceptibility for extended autoimmune/inflammatory disorders, being considered a common risk factor in autoimmunity. NLRP1 provides a scaffold for the assembly of the inflammasome that activates caspases 1 and 5, required for processing and activation of the proinflammatory cytokines interleukin 1β (IL-1β), IL-18 and IL-33 and promoting inflammation

Corrigendum: Analysis of the common genetic component of large-vessel vasculitides through a meta-Immunochip strategy.

Giant cell arteritis (GCA) and Takayasu's arteritis (TAK) are major forms of large-vessel vasculitis (LVV) that share clinical features. To evaluate their genetic similarities, we analysed Immunochip genotyping data from 1,434 LVV patients and 3,814 unaffected controls. Genetic pleiotropy was also estimated. The HLA region harboured the main disease-specific associations. GCA was mostly associated with class II genes (HLA-DRB1/HLA-DQA1) whereas TAK was mostly associated with class I genes (HLA-B/MICA). Both the statistical significance and effect size of the HLA signals were considerably reduced in the cross-disease meta-analysis in comparison with the analysis of GCA and TAK separately. Consequently, no significant genetic correlation between these two diseases was observed when HLA variants were tested. Outside the HLA region, only one polymorphism located nearby the IL12B gene surpassed the study-wide significance threshold in the meta-analysis of the discovery datasets (rs755374, P\u2009=\u20097.54E-07; ORGCA\u2009=\u20091.19, ORTAK\u2009=\u20091.50). This marker was confirmed as novel GCA risk factor using four additional cohorts (PGCA\u2009=\u20095.52E-04, ORGCA\u2009=\u20091.16). Taken together, our results provide evidence of strong genetic differences between GCA and TAK in the HLA. Outside this region, common susceptibility factors were suggested, especially within the IL12B locus