Regulated spatial organization and sensitivity of cytosolic protein oxidation in Caenorhabditis elegans

Cells adjust their behavior in response to redox events by regulating protein activity through the reversible formation of disulfide bridges between cysteine thiols. However, the spatial and temporal control of these modifications remains poorly understood in multicellular organisms. Here, we measured the protein thiol-disulfide balance in live C. elegans using a genetically-encoded redox sensor and found that it is specific to tissues and patterned spatially within a tissue. Insulin signaling regulates the sensor's oxidation at both of these levels. Unexpectedly, we found that isogenic individuals exhibit large differences in the sensor's thiol-disulfide balance. This variation contrasts with the general view that glutathione acts as the main cellular redox buffer. Indeed, our work suggests that glutathione converts small changes in its oxidation level into large changes in its redox potential. We therefore propose that glutathione facilitates the sensitive control of the thioldisulfide balance of target proteins in response to cellular redox events

Simulación de actividades en red local

El presente trabajo es continuidad del Modelado de Actividades en Redes Locales presentado en WICC2007 y se inscribe dentro del proyecto que intenta desarrollar las bases teóricas de un simulador de la actividad de la red de computadoras de la UNLAM. El propósito es doble; por un lado se trata de elaborar una herramienta para evaluar en forma simulada el desempeño de la red ante un eventual aumento del tráfico de tramas y conocer así probables situaciones de congestionamiento y por el otro , se pretende diseñar una herramienta propia que sirva de apoyo didáctico para la enseñanza de conocimientos sobre re des de computadoras. La simulación prevista considera cada trama desde que es emitida por una estación de trabajo hasta que arriba a su destino. Para ello se identificaron como relevantes la s actividades de emisión de tramas y de procesamiento en el switch. A su vez la longitud, el origen, el destino y la prioridad de proceso resultan los atributos principales a simular en cada trama. Obtenidos desde un tráfico real, los patrones de comportamiento estadístico de estos atributos y de las acti vidades señaladas, se podrán utilizar como regla probabilística , y por medio de técnicas de Monte Carlo obtener un tráfico simulado a través de la red. El realizarlo implica resolver ciertas dificultades , pues la simulación debe actuar siguiendo un reloj con el que se actualiza el sistema cuando una trama es emitida, cuando e ntra al switch o cuando sale de él. Por lo tanto resulta necesario extraer, desde datos reales, el comportamiento probabilístico de lo s tiempos entre emisión de tramas y de los tiempos de proceso en el switch En el trabajo anterior se confirmó la hipó tesis de que la emisión de tramas hacia la red es un proceso aleatorio de carácter Poisson – exponencial. En la continuidad de la tarea, se trata ahora de establecer los patrones estadísticos de los atributos señalados de las tramas y de la actividad de procesamiento en el switch . De acuerdo al cronograma fijado para el proyecto se ha trabajado en los aspectos que se detallan a continuación.Eje: Arquitectura, Redes y Sistemas OperativosRed de Universidades con Carreras en Informática (RedUNCI

Simulación de actividades en red local

El presente trabajo es continuidad del Modelado de Actividades en Redes Locales presentado en WICC2007 y se inscribe dentro del proyecto que intenta desarrollar las bases teóricas de un simulador de la actividad de la red de computadoras de la UNLAM. El propósito es doble; por un lado se trata de elaborar una herramienta para evaluar en forma simulada el desempeño de la red ante un eventual aumento del tráfico de tramas y conocer así probables situaciones de congestionamiento y por el otro , se pretende diseñar una herramienta propia que sirva de apoyo didáctico para la enseñanza de conocimientos sobre re des de computadoras. La simulación prevista considera cada trama desde que es emitida por una estación de trabajo hasta que arriba a su destino. Para ello se identificaron como relevantes la s actividades de emisión de tramas y de procesamiento en el switch. A su vez la longitud, el origen, el destino y la prioridad de proceso resultan los atributos principales a simular en cada trama. Obtenidos desde un tráfico real, los patrones de comportamiento estadístico de estos atributos y de las acti vidades señaladas, se podrán utilizar como regla probabilística , y por medio de técnicas de Monte Carlo obtener un tráfico simulado a través de la red. El realizarlo implica resolver ciertas dificultades , pues la simulación debe actuar siguiendo un reloj con el que se actualiza el sistema cuando una trama es emitida, cuando e ntra al switch o cuando sale de él. Por lo tanto resulta necesario extraer, desde datos reales, el comportamiento probabilístico de lo s tiempos entre emisión de tramas y de los tiempos de proceso en el switch En el trabajo anterior se confirmó la hipó tesis de que la emisión de tramas hacia la red es un proceso aleatorio de carácter Poisson – exponencial. En la continuidad de la tarea, se trata ahora de establecer los patrones estadísticos de los atributos señalados de las tramas y de la actividad de procesamiento en el switch . De acuerdo al cronograma fijado para el proyecto se ha trabajado en los aspectos que se detallan a continuación.Eje: Arquitectura, Redes y Sistemas OperativosRed de Universidades con Carreras en Informática (RedUNCI

A computational modeling for real ecosystems based on P systems

In this paper, a P systems based general framework for modeling ecosystems dynamics is presented. Particularly, ecosystems are specified by means of multienvironment P systems composed of a finite number of environments, each of them having an extended P system with active membranes. The semantics is of a probabilistic type and it is implemented by assigning each rule of the system a probabilistic constant which depends on the environment and the run time. As a case study, two real ecosystems are described: scavenger birds in the Catalan Pyrenees and the zebra mussel (Dreissena Polymorpha) in Ribarroja reservoir (Spain).Ministerio de Ciencia e Innovación TIN2009–13192Junta de Andalucía P08–TIC-0420

Posible rol de la gallareta chica (Fulica leucoptera) en la contaminación de aguas superficiales con quistes de Giardia sp. (Orden Diplomonadida, fam.Hexamitidae)

Giardia sp. is a genus of endoparasite protozoo of the small intestine, responsible for infections generally asymptomatic, especially in children. They can cause acute, sub acute, and chronic diarrheas and duodenal irritation with increment of the mucus and deficiencies in the absorption of liposolubles vitamins. Giardia sp. can inhibit the activity of the pancreatic lipasa causing mal absorption of fats. Their cysts remain viable more than two weeks in humid areas and the way of infection is by ingestion of water or polluted foods with cysts. Studies carried out in the Canadian goose (Branta canadensis) determined the presence of cysts of Giardia sp. in the faecal pellets of these birds, and considering their migratory nature the possible dissemination of the parasite has special interest. Giardia sp.has been also identified in feces of other aquatic birds that are considered reservoirs. The small gallareta (Fulica leucoptera) possesses a wide and profuse distribution in Argentina. It occupies a similar ecological niche of that of the Canadian goose, so their possible participation in the contamination of the superficial waters with cysts of Giardia sp. can be considere. With the purpose of testing this possibility, were captured some gallaretas in the complex Nordelta-Tigre (Bs. As., Argentina), taking samples of faecal pellets and duodenal content. The carried out studies did not showed Giardia sp. Anyway, it should be taken in to consideration the small size of the sample and it restricted geographical representation before possible epidemic inferences. The results provide original information on the rol of the wild aquatic birds as possible agents of dispersion of parasitosis whit importance in public health.Giardia sp. is a genus of endoparasite protozoo of the small intestine, responsible for infections generally asymptomatic, especially in children. They can cause acute, sub acute, and chronic diarrheas and duodenal irritation with increment of the mucus and deficiencies in the absorption of liposolubles vitamins. Giardia sp. can inhibit the activity of the pancreatic lipasa causing mal absorption of fats. Their cysts remain viable more than two weeks in humid areas and the way of infection is by ingestion of water or polluted foods with cysts. Studies carried out in the Canadian goose (Branta canadensis) determined the presence of cysts of Giardia sp. in the faecal pellets of these birds, and considering their migratory nature the possible dissemination of the parasite has special interest. Giardia sp.has been also identified in feces of other aquatic birds that are considered reservoirs. The small gallareta (Fulica leucoptera) possesses a wide and profuse distribution in Argentina. It occupies a similar ecological niche of that of the Canadian goose, so their possible participation in the contamination of the superficial waters with cysts of Giardia sp. can be considere. With the purpose of testing this possibility, were captured some gallaretas in the complex Nordelta-Tigre (Bs. As., Argentina), taking samples of faecal pellets and duodenal content. The carried out studies did not showed Giardia sp. Anyway, it should be taken in to consideration the small size of the sample and it restricted geographical representation before possible epidemic inferences. The results provide original information on the rol of the wild aquatic birds as possible agents of dispersion of parasitosis whit importance in public health

Posible rol de la gallareta chica (<i>Fulica leucoptera</i>) en la contaminación de aguas superficiales con quistes de <i>Giardia</i> sp. (Orden Diplomonadida, fam. Hexamitidae)

Giardia sp. is a genus of endoparasite protozoo of the small intestine, responsible for infections generally asymptomatic, especially in children. They can cause acute, sub acute, and chronic diarrheas and duodenal irritation with increment of the mucus and deficiencies in the absorption of liposolubles vitamins. Giardia sp. can inhibit the activity of the pancreatic lipasa causing mal absorption of fats. Their cysts remain viable more than two weeks in humid areas and the way of infection is by ingestion of water or polluted foods with cysts. Studies carried out in the Canadian goose (Branta canadensis) determined the presence of cysts of Giardia sp. in the faecal pellets of these birds, and considering their migratory nature the possible dissemination of the parasite has special interest. Giardia sp.has been also identified in feces of other aquatic birds that are considered reservoirs. The small gallareta (Fulica leucoptera) possesses a wide and profuse distribution in Argentina. It occupies a similar ecological niche of that of the Canadian goose, so their possible participation in the contamination of the superficial waters with cysts of Giardia sp. can be considere. With the purpose of testing this possibility, were captured some gallaretas in the complex Nordelta-Tigre (Bs. As., Argentina), taking samples of faecal pellets and duodenal content. The carried out studies did not showed Giardia sp. Anyway, it should be taken in to consideration the small size of the sample and it restricted geographical representation before possible epidemic inferences. The results provide original information on the rol of the wild aquatic birds as possible agents of dispersion of parasitosis whit importance in public health.Instituto de Limnología "Dr. Raúl A. Ringuelet

Posible rol de la gallareta chica (<i>Fulica leucoptera</i>) en la contaminación de aguas superficiales con quistes de <i>Giardia</i> sp. (Orden Diplomonadida, fam. Hexamitidae)

Giardia sp. is a genus of endoparasite protozoo of the small intestine, responsible for infections generally asymptomatic, especially in children. They can cause acute, sub acute, and chronic diarrheas and duodenal irritation with increment of the mucus and deficiencies in the absorption of liposolubles vitamins. Giardia sp. can inhibit the activity of the pancreatic lipasa causing mal absorption of fats. Their cysts remain viable more than two weeks in humid areas and the way of infection is by ingestion of water or polluted foods with cysts. Studies carried out in the Canadian goose (Branta canadensis) determined the presence of cysts of Giardia sp. in the faecal pellets of these birds, and considering their migratory nature the possible dissemination of the parasite has special interest. Giardia sp.has been also identified in feces of other aquatic birds that are considered reservoirs. The small gallareta (Fulica leucoptera) possesses a wide and profuse distribution in Argentina. It occupies a similar ecological niche of that of the Canadian goose, so their possible participation in the contamination of the superficial waters with cysts of Giardia sp. can be considere. With the purpose of testing this possibility, were captured some gallaretas in the complex Nordelta-Tigre (Bs. As., Argentina), taking samples of faecal pellets and duodenal content. The carried out studies did not showed Giardia sp. Anyway, it should be taken in to consideration the small size of the sample and it restricted geographical representation before possible epidemic inferences. The results provide original information on the rol of the wild aquatic birds as possible agents of dispersion of parasitosis whit importance in public health.Instituto de Limnología "Dr. Raúl A. Ringuelet

Posible rol de la gallareta chica (<i>Fulica leucoptera</i>) en la contaminación de aguas superficiales con quistes de <i>Giardia</i> sp. (Orden Diplomonadida, fam. Hexamitidae)

Giardia sp. is a genus of endoparasite protozoo of the small intestine, responsible for infections generally asymptomatic, especially in children. They can cause acute, sub acute, and chronic diarrheas and duodenal irritation with increment of the mucus and deficiencies in the absorption of liposolubles vitamins. Giardia sp. can inhibit the activity of the pancreatic lipasa causing mal absorption of fats. Their cysts remain viable more than two weeks in humid areas and the way of infection is by ingestion of water or polluted foods with cysts. Studies carried out in the Canadian goose (Branta canadensis) determined the presence of cysts of Giardia sp. in the faecal pellets of these birds, and considering their migratory nature the possible dissemination of the parasite has special interest. Giardia sp.has been also identified in feces of other aquatic birds that are considered reservoirs. The small gallareta (Fulica leucoptera) possesses a wide and profuse distribution in Argentina. It occupies a similar ecological niche of that of the Canadian goose, so their possible participation in the contamination of the superficial waters with cysts of Giardia sp. can be considere. With the purpose of testing this possibility, were captured some gallaretas in the complex Nordelta-Tigre (Bs. As., Argentina), taking samples of faecal pellets and duodenal content. The carried out studies did not showed Giardia sp. Anyway, it should be taken in to consideration the small size of the sample and it restricted geographical representation before possible epidemic inferences. The results provide original information on the rol of the wild aquatic birds as possible agents of dispersion of parasitosis whit importance in public health.Instituto de Limnología "Dr. Raúl A. Ringuelet

Deterministic and stochastic P systems for modelling cellular processes

This paper presents two approaches based on metabolic and stochastic P systems, together with their associated analysis methods, for modelling biological sys- tems and illustrates their use through two case studies.Kingdom's Engineering and Physical Sciences Research Council EP/ E017215/1Biotechnology and Biological Sciences Research Council/United Kingdom BB/D019613/1Biotechnology and Biological Sciences Research Council/United Kingdom BB/F01855X/

Modelling the fraction of Lyman Break Galaxies with strong Lyman alpha emission at 5 < z < 7

We present theoretical results for the expected fraction of Lyman Break Galaxies (LBGs) to be detected as strong Lyman alpha emitters (LAEs) in the redshift range 5 < z < 7. We base our analysis on the 2-billion particle SPH simulation MareNostrum High-z Universe. We approximate galaxies as static dusty slabs with an additional clumpy dust distribution affecting stellar populations younger than 25 Myr. The model for the Lyman alpha escape fraction is based on the results of our Monte-Carlo radiative transfer code (CLARA) for a slab configuration. We also fix the transmission of Lyman alpha photons through the intergalactic medium to a constant value of 50% at all redshifts. From the results of this model we calculate xLya, the fraction of Lyman Break Galaxies with Lyman alpha equivalent width (EW) larger than 50 Angstrom. We find a remarkable agreement with observational data at 4.5 < z < 6. For bright (-22 < MUV < -20.5) and faint (-20.5 < MUV < -18.5) galaxies our model predicts xLya = 0.02 \pm 0.01 and xLya = 0.47 \pm 0.01 while observers report xLya = 0.08 \pm 0.02 and xLya = 0.47 \pm 0.16, respectively. Additional evolution of the extinction model at redshift z \sim 7, that decreases the intensity of transmitted Lyman alpha radiation by a factor of f_T = 0.4 as to match the LAE luminosity function at z \sim 6.5, naturally provides a good match for the recently reported xLya fractions at z > 6.3. Exploring different toy models for the Lyman alpha escape fraction, we show that a decreasing Lyman alpha escape fraction with increasing UV galaxy luminosity is a key element in our model to explain the of larger xLya fractions for fainter LBGs.Comment: 7 pages, 3 figures. Accepted for publication in MNRA