Dynamic recruitment of Ets1 to both nucleosome-occupied and -depleted enhancer regions mediates a transcriptional program switch during early T-cell differentiation.

Ets1 is a sequence-specific transcription factor that plays an important role during hematopoiesis, and is essential for the transition of CD4(-)/CD8(-) double negative (DN) to CD4(+)/CD8(+) double positive (DP) thymocytes. Using genome-wide and functional approaches, we investigated the binding properties, transcriptional role and chromatin environment of Ets1 during this transition. We found that while Ets1 binding at distal sites was associated with active genes at both DN and DP stages, its enhancer activity was attained at the DP stage, as reflected by levels of the core transcriptional hallmarks H3K4me1/3, RNA Polymerase II and eRNA. This dual, stage-specific ability reflected a switch from non-T hematopoietic toward T-cell specific gene expression programs during the DN-to-DP transition, as indicated by transcriptome analyses of Ets1(-/-) thymic cells. Coincidentally, Ets1 associates more specifically with Runx1 in DN and with TCF1 in DP cells. We also provide evidence that Ets1 predominantly binds distal nucleosome-occupied regions in DN and nucleosome-depleted regions in DP. Finally and importantly, we demonstrate that Ets1 induces chromatin remodeling by displacing H3K4me1-marked nucleosomes. Our results thus provide an original model whereby the ability of a transcription factor to bind nucleosomal DNA changes during differentiation with consequences on its cognate enhancer activity.

IL-12 Signaling Contributes to the Reprogramming of Neonatal CD8+ T Cells.

Neonates are highly susceptible to intracellular pathogens, leading to high morbidity and mortality rates. CD8+ T lymphocytes are responsible for the elimination of infected cells. Understanding the response of these cells to normal and high stimulatory conditions is important to propose better treatments and vaccine formulations for neonates. We have previously shown that human neonatal CD8+ T cells overexpress innate inflammatory genes and have a low expression of cytotoxic and cell signaling genes. To investigate the activation potential of these cells, we evaluated the transcriptome of human neonatal and adult naïve CD8+ T cells after TCR/CD28 signals ± IL-12. We found that in neonatal cells, IL-12 signals contribute to the adult-like expression of genes associated with cell-signaling, T-cell cytokines, metabolism, and cell division. Additionally, IL-12 signals contributed to the downregulation of the neutrophil signature transcription factor CEBPE and other immaturity related genes. To validate the transcriptome results, we evaluated the expression of a series of genes by RT-qPCR and the promoter methylation status on independent samples. We found that in agreement with the transcriptome, IL-12 signals contributed to the chromatin closure of neutrophil-like genes and the opening of cytotoxicity genes, suggesting that IL-12 signals contribute to the epigenetic reprogramming of neonatal lymphocytes. Furthermore, high expression of some inflammatory genes was observed in naïve and stimulated neonatal cells, in agreement with the high inflammatory profile of neonates to infections. Altogether our results point to an important contribution of IL-12 signals to the reprogramming of the neonatal CD8+ T cells.

Cooperation between T cell receptor and Toll-like receptor 5 signaling for CD4+ T cell activation.

CD4+ T cells recognize antigens through their T cell receptors (TCRs); however, additional signals involving costimulatory receptors, for example, CD28, are required for proper T cell activation. Alternative costimulatory receptors have been proposed, including members of the Toll-like receptor (TLR) family, such as TLR5 and TLR2. To understand the molecular mechanism underlying a potential costimulatory role for TLR5, we generated detailed molecular maps and logical models for the TCR and TLR5 signaling pathways and a merged model for cross-interactions between the two pathways. Furthermore, we validated the resulting model by analyzing how T cells responded to the activation of these pathways alone or in combination, in terms of the activation of the transcriptional regulators CREB, AP-1 (c-Jun), and NF-κB (p65). Our merged model accurately predicted the experimental results, showing that the activation of TLR5 can play a similar role to that of CD28 activation with respect to AP-1, CREB, and NF-κB activation, thereby providing insights regarding the cross-regulation of these pathways in CD4+ T cells.

The role of biotechnology in art preservation.

Biotechnology has played a key role in medicine, agriculture and industry for over 30 years and has advanced our understanding of the biological sciences. Furthermore, the tools of biotechnology have a great and largely untapped potential for the preservation and restoration of our cultural heritage. It is possible that these tools are not often applied in this context because of the inherent separation of the worlds of art and science; however, it is encouraging to see that during the past six years important biotechnological applications to artwork preservation have emerged and advances in biotechnology predict further innovation. In this article we describe and reflect upon a unique example of a group of scientists and art restoration technicians working together to study and treat of a piece of colonial art, and review some of the new applications in biotechnology for the preservation of mankind's cultural heritage. We predict an expansion in this field and the further development of biotechnological techniques, which will open up new opportunities to both biologists and artwork preservers.

Biodistribution of liposome-entrapped human gamma-globulin.

The present study was aimed at the preparation and performance evaluation of Intacglobin-loaded liposomes for selective drug presentation to the lungs. Egg phosphatidylcholine- and cholesterol-based liposomes (1:1 and 1:0.25 mol/mol) were prepared by a dehydration-rehydration procedure. A tissue distribution study after single intranasal administration of 0.5 microCi 125I-Intacglobin-loaded liposomes was conducted in Balb/c mice. The efficiencies of drug entrapment (30%) and the average diameters did not differ significantly between the two liposome formulations. However, liposomes composed of an increased cholesterol amount showed a lower in vitro drug release rate. The airway penetration efficiency of the liposomal formulation was determined by the cumulative percentage of the dose reaching the lungs (AUC) and its sojourn time therein, and were 1.7- and 2.2-times higher compared with the plain 125I- Intacglobin solution-based formulation, respectively. A significantly greater (p<0.001) drug localization index after 24 h was found at the lungs in comparison with the other tissues (p<0.01), although similar values were detected between groups following administration of either liposomes or control solutions, despite the formulations attributes. In conclusion, it is suggested that longer Intacglobin exposure at the pulmonary region is observed after administration of the liposomal formulation. The results open future perspectives in assessing local passive immunization for the treatment of respiratory infectious diseases.

IDENTIFICACIÓN DEL AGENTE CAUSAL DE UNA BACTERIOSIS EN ÑAME (Dioscorea alata L.) / ISOLATION AND IDENTIFICATION OF A PHYTOPATHOGENIC BACTERIA FROM WATER YAM (Dioscorea alata L.) / IDENTIFICAÇÃO DO AGENTE CAUSAL DE UMA BACTERIOSE NO INHAME (Dioscorea alata L.)

El ñame (Dioscorea alata L.), ampliamente usado como fuente de calorías en África, Asia y el Caribe, es una planta herbácea y trepadora que se reproduce generalmente de forma vegetativa y produce un tubérculo comestible de gran tamaño con alto contenido de almidón. Varios microorganismos fitopatógenos, incluyendo virus, hongos y bacterias, afectan al cultivo. Plantas enfermas de la zona de Guarataro, estado Bolívar, Venezuela, fueron colectadas en el 2003, año en que hubo ~80% de pérdidas en la producción de ñame de la zona a causa de una enfermedad desconocida. Hojas colectadas de plantas enfermas con lesiones acuosas y necróticas fueron esterilizadas superficialmente y transferidas a solución salina para permitir la difusión de bacterias desde los bordes del tejido y ser luego sembradas en medio LB agar. Como controles se emplearon agua y medio LB. Colonias amarillas, brillantes y lisas, fueron visibles a las 24-48h de incubación a 30ºC. Varios aislados fueron inoculados en las pruebas de hipersensibilidad en tabaco y de patogenicidad en plántulas de ñame cultivadas in vitro. Varios grados de respuesta de hipersensibilidad en tabaco fueron observados. Las plántulas de ñame inoculadas mostraron lesiones acuosas en la lámina foliar, las cuales no se observaron en los controles. Aislados bacterianos fueron observados mediante microscopía de luz, revelando bacterias bacilares Gram negativas. Varios flagelos peritricos fueron observados por microscopía electrónica. Los resultados de las pruebas bioquímicas y fisiológicas indicaron que los aislados corresponden a Pantoea agglomerans (Enterobacteriacea). Se discuten diferentes metodologías para la identificación de bacterias.

Water yam (Dioscorea alata L.), a staple crop in Africa, Asia and the Caribbean, is a herbaceous twining vine plant generally reproduced by vegetative sections and highly affected by several phytopathogenic organisms including virus, fungi and bacteria. Diseased plants were collected from Guarataro, Bolívar State, Venezuela, in 2003. That year an unknown disease led to ~80% loss of water yam production. The leaves from diseased plants have watery or necrotic lesions on the leaf lamina. Pieces of necrotic tissue were surface sterilized, then transferred to saline solution and the bacteria allowed to diffuse into the solution from the edge of the dissected tissue. The bacteria were isolated on LB agar media. Yellow, shining, smooth colonies with regular margins were visible within 24-48h of incubation at 30ºC. Several isolates were inoculated on tobacco plants. Water and LB media were used as negative controls. Several degrees of hypersensitivity response resulted from the inoculation of tobacco. However, inoculation of in vitro water yam plants showed watering lesions on the leaf lamina inoculated with bacteria cultures and no lesions on water and media inoculated leaves. Bacterial cells observed by light microscopy showed Gram-negative regular rods. Several peritricous flagella were observed under EM. Data from biochemical and physiological tests indicated that the isolates belong to the Enterobacteriaceas family specifically to Pantoea agglomerans. Different methodologies for bacterial identification are discussed.

O inhame (Dioscorea alata L.), amplamente usado como fonte de calorias na África, Ásia e no Caribe, é uma planta herbácea e trepadeira que se reproduz geralmente de forma vegetativa e produz um tubérculo comestível de grande tamanho com alto conteúdo de amido. Vários microorganismos fitopatógenos, incluindo vírus, fungos e bactérias, afetam ao cultivo. Plantas enfermas da zona de Guarataro, estado Bolívar, Venezuela, foram coletadas em 2003, ano em que houve ~80% de perdas na produção de inhame dessa zona a causa de uma enfermidade desconhecida. Folhas coletadas de plantas enfermas com lesões aquosas e necróticas foram esterilizadas superficialmente e transferidas a uma solução salina para permitir a difusão de bactérias desde as bordas do tecido e ser logo plantadas em meio LBA. Como controles foram empregados água e meio LBA. Colônias amarelas, brilhantes e lisas, foram visíveis às 24-48h de incubação a 30ºC. Vários isolados foram inoculados nas provas de hipersensibilidade em tabaco e de patogenicidade em plântulas de inhame cultivadas in vitro. Vários graus de resposta de hipersensibilidade em tabaco foram observados. As de plântulas de inhame inoculadas mostraram lesões aquosas na lâmina foliar, as quais não se observaram nos controles. Isolados bacterianos foram observados mediante microscopia de luz, revelando bactérias bacilares Gram negativas. Vários flagelos perítricos foram observados por microscopia eletrônica. Os resultados das provas bioquímicas e fisiológicas indicaram que os isolados correspondem a Pantoea agglomerans (Enterobacteriacea). Discutem-se diferentes metodologias para a identificação de.