La nueva pintura del emperador

El texto repasa la conocida "Ley de Ripolin" que Le Corbusier expone en su famoso texto L'art décoratif d'aujourd'hui, en el que el arquitecto suizo aspira a encontrar respuesta a la pregunta fundamental: ¿dónde está la arquitectura? A partir de una brillante reflexión sobre el papel de las paredes blancas en la arquitectura moderna, Wigley rescata el carácter textil y en consecuencia "superficial" de la condición moderna de la arquitectura. De este modo se muestra cómo la arquitectura de Le Corbusier enlaza con los argumentos de Loos y Semper, y más aun se ve con claridad la auténtica condición de la arquitectura como fenómeno visual que a su vez se localiza en el espacio de la comunicación. Como Wigley apunta, es necesario explorar con mucho detalle la fina capa blanca y para eso es preciso ahondar con mucha más profundidad en la superficie

The Bacterial Clients of Modern Architecture

The human is an unstable idea; simultaneously an all-powerful creature – capable of transforming the whole ecology of the planet – yet extremely fragile, a murky ghost. Contemporary research into our microbiome portrays the human itself as a mobile ecology constructed by the endless flux of interactions between thousands of different species of bacteria – some of which are millions of years old and others joined us just a few months ago. This challenges conventional understandings of architecture. What does it mean to house the human when we no longer think that the human organism is securely contained within its skin? What is the role of architecture when the humans occupying it are understood to be suspended in clouds of bacteria shared, generated and mobilized by other macro-organisms (pets, plants, insects…) and the building itself; when the human is not a clearly defined organism or in any sense independent; when the architectural client is a massive set of ever-changing trans-species alliances that make the apparent complexity of even the largest of cities seem quaintly uncomplicated. What kind of care do architects offer if we think of ourselves as alliances between bacteria within the apparent limits of the body and throughout the spaces we occupy? What faces 21st century architects in comparison to 20th century architects

“And” Anarchitectures

Architecture and Philosophy are so deeply entangled with each other that the “and” between them at once splits and rejoins a single common fabric. This enigmatic joint, and the mutual jealousies, clum-siness, and blindness it puts in motion, has a very long history. The in-terdependency it shapes made possible the emergence of both discourses in Ancient Greece. Architecture appeared as an exemplary theoretical art, yet already subordinated to the discourse of Philosophy that is co-vertly dependent on it. This essay explores the anarchitectural ecology that made both discourses possible, along with the implications for con-temporary theory, and possible unexpected architectures

La policía de la moda

Se presenta en castellano el texto del profesor Wigley que originalmente constituye el segundo capítulo de su conocido White Walls, Designer Dresses. The Fashioning of Modern Architecture. El texto profundiza con brillantez en la compleja relación entre moda y arquitectura moderna. Parte de la convicción de que "el discurso contemporáneo sobre la arquitectura continúa organizado alrededor de los continuos ataques a la moda". Para mostrar esta realidad repasa la actitud defensiva y en ocasiones de "perro guardian" de algunos de sus principales representantes teóricos: desde Le Corbusier y sus escritos sobre las paredes blancas, hasta Giedion, cuya posición es rastreada con minuciosidad a lo largo de sus principales escritos, hasta Tafuri, que en su influyente Teoría e Historia de la Arquitectura presenta una similar actitud hacia la moda. Wigley concluye mostrando cómo estos rechazos de la moda son en definitiva una prueba de su vigencia como disciplina y explica que, en consecuencia, "ningún discurso puede aislarse de la moda sin más"

Structures of RecBCD in complex with phage-encoded inhibitor proteins reveal distinctive strategies for evasion of a bacterial immunity hub

Following infection of bacterial cells, bacteriophage modulate double-stranded DNA break repair pathways to protect themselves from host immunity systems and prioritise their own recombinases. Here, we present biochemical and structural analysis of two phage proteins, gp5.9 and Abc2, which target the DNA break resection complex RecBCD. These exemplify two contrasting mechanisms for control of DNA break repair in which the RecBCD complex is either inhibited or co-opted for the benefit of the invading phage. Gp5.9 completely inhibits RecBCD by preventing it from binding to DNA. The RecBCD-gp5.9 structure shows that gp5.9 acts by substrate mimicry, binding predominantly to the RecB arm domain and competing sterically for the DNA binding site. Gp5.9 adopts a parallel coiled-coil architecture that is unprecedented for a natural DNA mimic protein. In contrast, binding of Abc2 does not substantially affect the biochemical activities of isolated RecBCD. The RecBCD-Abc2 structure shows that Abc2 binds to the Chi-recognition domains of the RecC subunit in a position that might enable it to mediate the loading of phage recombinases onto its single-stranded DNA products

Insights into Chi recognition from the structure of an AddAB-type helicase–nuclease complex

Homologous recombination DNA repair requires double-strand break resection by helicase–nuclease enzymes. The crystal structure of bacterial AddAB in complex with DNA substrates shows that it employs an inactive helicase site to recognize ‘Chi' recombination hotspot sequences that regulate resection

Chi hotspots trigger a conformational change in the helicase-like domain of AddAB to activate homologous recombination

In bacteria, the repair of double-stranded DNA breaks is modulated by Chi sequences. These are recognised by helicase-nuclease complexes that process DNA ends for homologous recombination. Chi activates recombination by changing the biochemical properties of the helicase-nuclease, transforming it from a destructive exonuclease into a recombination-promoting repair enzyme. This transition is thought to be controlled by the Chi-dependent opening of a molecular latch, which enables part of the DNA substrate to evade degradation beyond Chi. Here, we show that disruption of the latch improves Chi recognition efficiency and stabilizes the interaction of AddAB with Chi, even in mutants that are impaired for Chi binding. Chi recognition elicits a structural change in AddAB that maps to a region of AddB which resembles a helicase domain, and which harbours both the Chi recognition locus and the latch. Mutation of the latch potentiates the change and moderately reduces the duration of a translocation pause at Chi. However, this mutant displays properties of Chi-modified AddAB even in the complete absence of bona fide hotspot sequences. The results are used to develop a model for AddAB regulation in which allosteric communication between Chi binding and latch opening ensures quality control during recombination hotspot recognition

Using the past to constrain the future: how the palaeorecord can improve estimates of global warming

Climate sensitivity is defined as the change in global mean equilibrium temperature after a doubling of atmospheric CO2 concentration and provides a simple measure of global warming. An early estimate of climate sensitivity, 1.5-4.5{\deg}C, has changed little subsequently, including the latest assessment by the Intergovernmental Panel on Climate Change. The persistence of such large uncertainties in this simple measure casts doubt on our understanding of the mechanisms of climate change and our ability to predict the response of the climate system to future perturbations. This has motivated continued attempts to constrain the range with climate data, alone or in conjunction with models. The majority of studies use data from the instrumental period (post-1850) but recent work has made use of information about the large climate changes experienced in the geological past. In this review, we first outline approaches that estimate climate sensitivity using instrumental climate observations and then summarise attempts to use the record of climate change on geological timescales. We examine the limitations of these studies and suggest ways in which the power of the palaeoclimate record could be better used to reduce uncertainties in our predictions of climate sensitivity.Comment: The final, definitive version of this paper has been published in Progress in Physical Geography, 31(5), 2007 by SAGE Publications Ltd, All rights reserved. \c{opyright} 2007 Edwards, Crucifix and Harriso

Engineering a reagentless biosensor for single-stranded DNA to measure real-time helicase activity in Bacillus

Single-stranded DNA-binding protein(SSB)is a well characterized ubiquitous and essential bacterial protein involved in almost all aspects of DNA metabolism. Using the Bacillus subtilis SSB we have generated areagentless SSB biosensor that can be used as a helicase probe in B. subtilis and closely related gram positive bacteria. We have demonstrated the utility of the probe in a DNA unwinding reaction using a helicase from Bacillus and for the first time,characterized the B. subtilis SSB's DNA binding mode switching and stoichiometry.The importance of SSB in DNA metabolism is not limited to simply binding and protecting ssDNA during DNA replication, as previously thought. It interacts with an array of partner proteins to coordinate many different aspects of DNA metabolism. In most cases its interactions with partner proteins is species-specific and for this reason, knowing how to produce and use cognate reagentless SSB biosensors indifferent bacteria is critical.Here we explain how to produce a B. subtilis SSB probe that exhibits 9-fold fluorescence increase upon binding to single stranded DNA and can be used in all related grampositive firmicutes which employ drastically different DNA replication and repair systems than the widely studied Escherichiacoli. The materials to produce the B. subtilis SSB probe a recommercially available, so the methodology described here is widely available unlike previously published methods for the E. coli SSB