Cambio conceptual, filosofla del lenguaje y subjetividad.

Sin resume

Tres procesos judiciales: hacia una estética del acontecimiento

The problem of drawing a significant analogy between three events at first sight hardly comparable is described, namely, the trials of Socrates, Galileo, and Joseph K. Some main interpretations are analyzed but all of them are found nor really satisfactory. An alternative approach is then introduced -an «esthetic of the event»- which discloses a deep analogy between the three trials. So it is argued, first, that in the background of all the three events a crisis of the articulation between the world image, the form of life, and meaning was developing. And, secondly, it is also argued that the three trials are archetypical modes of the clash between the individual and Power.Se formula el problema de trazar una analogía entre tres acontecimientos en principio difícilmente comparables entre sí: los procesos de Sócrates, Galileo y Josef K. Se analizan las principales interpretaciones que se han dado de cada uno de ellos y se concluye que son insatisfactorias. Se propone un enfoque alternativo -una estética del acontecimiento-, el cual pone de manifiesto una analogía profunda entre los tres procesos. Se argumenta, en primer lugar, que los tres procesos han tenido como trasfondo una crisis de la articulación entre la imagen del mundo, la forma de vida y el sentido. Y, en segundo lugar, que los tres son modos arquetípicos de enfrentamiento entre el Poder y el individuo

Hacia un modelo de cambio conceptual: espacios controversiales y refocalización

A model of the dynamics of conceptual change in science and philosophy is proposed. It is assumed that even in revolutionary conceptual changes there is a web of continuities and discontinuities operating at the same time. Similarities and differences of this view both with the classical and the Kuhnian views of conceptual change are pointed out. Finally, after introducing a new unit of analysis –controversial spaces– conceptual change is construed as a process of refocusing and restructuring of such spaces

Coupling between transcription termination and RNA polymerase inchworming

AbstractAdvancement of RNA polymerase of E. coli occurs in alternating laps of monotonic and inchworm-like movement. Cycles of inchworming are encoded in DNA and involve straining and relaxation of the ternary complex accompanied by characteristic leaping of DNA and RNA footprints. We demonstrate that the oligo(T) tract that constitutes a normal part of transcription terminators acts as an inchworming signal so that the leap coincides with the termination event. Prevention of leaping with a roadblock of cleavage-defective EcoRI protein results in suppression of RNA chain release at a termination site. The results indicate that straining and relaxation of RNA polymerase are steps in the termination mechanism

Revoluciones científicas: una paradoja cognitiva

El problema que me propongo abordar lo planteé por primera vez hace bastante tiempo y en relación con el cual hice en su momento algunos trabajos, en particular un articulo que salió hace varios años en Crítica (Nudler, 1976). Ahora, impulsado por nuevos e importantes trabajos que se conocieron desde entonces en las áreas de filosofía de la mente y psicología cognitiva, he decidido reformular mi enfoque de la cuestión

Cambio conceptual, filosofla del lenguaje y subjetividad.

Sin resume

H2S, a Bacterial Defense Mechanism against the Host Immune Response

The biological mediator hydrogen sulfide (H2S) is produced by bacteria and has been shown to be cytoprotective against oxidative stress and to increase the sensitivity of various bacteria to a range of antibiotic drugs. Here we evaluated whether bacterial H2S provides resistance against the immune response, using two bacterial species that are common sources of nosocomial infections, Escherichia coli and Staphylococcus aureus. Elevations in H2S levels increased the resistance of both species to immune-mediated killing. Clearances of infections with wild-type and genetically H2S-deficient E. coli and S. aureus were compared in vitro and in mouse models of abdominal sepsis and burn wound infection. Also, inhibitors of H2S- producing enzymes were used to assess bacterial killing by leukocytes. We found that inhibition of bacterial H2S production can increase the susceptibility of both bacterial species to rapid killing by immune cells and can improve bacterial clearance after severe burn, an injury that increases susceptibility to opportunistic infections. These findings support the role of H2S as a bacterial defense mechanism against the host response and implicate bacterial H2S inhibition as a potential therapeutic intervention in the prevention or treatment of infections

Bacterial Nitric Oxide Extends the Lifespan of C. elegans

SummaryNitric oxide (NO) is an important signaling molecule in multicellular organisms. Most animals produce NO from L-arginine via a family of dedicated enzymes known as NO synthases (NOSes). A rare exception is the roundworm Caenorhabditis elegans, which lacks its own NOS. However, in its natural environment, C. elegans feeds on Bacilli that possess functional NOS. Here, we demonstrate that bacterially derived NO enhances C. elegans longevity and stress resistance via a defined group of genes that function under the dual control of HSF-1 and DAF-16 transcription factors. Our work provides an example of interspecies signaling by a small molecule and illustrates the lifelong value of commensal bacteria to their host