Arqueología del futuro

A través de la historia aparecen muchas y variadas manifestaciones de cambio, necesarias para afrontar el futuro2 de la humanidad; también de la arquitectura. Estas manifestaciones, alternativas, teorías y proyectos, a menudo denostados por la crítica o dejados de lado por las teorías históricas de carácter generalista, destacan por su capacidad de convertirse en herramientas críticas frente al orden establecido, promoviendo así nuevos imaginarios colectivos. En el contexto temporal que transcurre desde finales de la década de los años cincuenta hasta mediados de los setenta, esa “búsqueda del futuro” no sólo se encuentra totalmente aceptada y popularizada, sino que llega a convertirse en un acto necesario, legitimado por la incorporación de la futurología como ciencia de estudio fundamental. Este contexto resulta el marco idóneo para la aparición de una serie de predicciones arquitectónicas encaminadas a dibujar nuevos caminos posibles para el futuro de la arquitectura, o lo que es lo mismo, para una arquitectura del futuro: “Où vivrons-nous demain ?” (1963) y “Les cités de l'avenir” (1966) del historiador francés Michel Ragon, el número “AD 2000+” (1967) de la revista Architectural Design y “The Future of the Future” (1969) del artista inglés John McHale, “Architecture: action and plan” (1967) y “Experimental Architecture” (1970) de Peter Cook, “Megastructure. Urban futures of the recent past” del crítico inglés Reyner Banham, “Architecture 2000” (1971) del norteamericano Charles Jencks, “Stadstrukturen für morgen” (1971) del suizo Justus Dahinden, “Arthropods: new design futures” (1972) del editor norteamericano Jim Burns y la sección “Cosmorama” (1965-1973) de la revista inglesa Architectural Design, pueden considerarse como las más destacadas. A pesar de lo heterogéneo de sus autores y enfoques, todas ellas gravitan en torno a cuatro alternativas para una redefinición del futuro de la arquitectura: - La incorporación de la arquitectura al heterogéneo espectro formal derivado de la explosión de las artes visuales y la exuberancia y proliferación de los objetos de consumo a través de un CAMBIO DE ESCALA. - La generación de nuevas relaciones que experimenten en torno a los límites entre natural y artificial, o PERVERSIONES NATURALES. - La apertura de un nuevo camino, HACIA UNA ARQUITECTURA VIRTUAL, que experimente con una construcción de ambientes auspiciada por los avances tecnológicos derivados del control perceptivo. - LA MOVILIDAD COMO OPCIÓN DE FUTURO, una respuesta a la aparición de una nueva sociedad en continuo cambio, abogando por estructuras más flexibles en todos los campos del ámbito arquitectónico, de lo urbano a lo doméstico. ABSTRACT of humanity, and of architecture too. Those signs, alternatives, theories and projects, that were often neglected by the critics or left aside by historical theories of general-interest, have an outstanding capacity to become critical tools with regards to the established order, and to promote new collective imagery. Within the timeframe that lasts between late fifties and midseventies, that "quest for the future" is not only accepted and made popular, but it even becomes an act of necessity that is legitimized by the incorporation of futurology as a key scientific field of study. This timeframe provides the most suitable context for the appearance of a series of architectonical predictions that are aimed to define new potential paths for the future architecture to follow, in other words, an architecture of the future: "Où vivrons-nous demain?" (1963) y "Les cités de l'avenir" (1966) from French historian Michel Ragon, issue number "AD 2000+" (1967) of Architectural Design magazine and "The Future of the Future" (1969) from English artist John McHale, "Architecture: action and plan" (1967) and "Experimental Architecture" (1970) from Peter Cook, "Megastructure. Urban futures of the recent past" from English critic Reyner Banham, "Architecture 2000" (1971) from North-American Charles Jencks, "Stadstrukturen für morgen" (1971) from Swiss Justus Dahinden, "Arthropods: new design futures" (1972) from North-American editor Jim Burns and the section "Cosmorama" (1965-73) from English magazine Architectural Design, can be considered as the most prominent architectonical predictions of that time. Despite the heterogeneity of authors and approaches, all of them are built around four alternatives that are aimed to re-define the future of architecture: - The incorporation of architecture to the heterogeneous formal spectrum of visual arts and the exuberance and the proliferation of objects of massive consumerism through an operation of CHANGE IN SCALE. - The production of new relationships aimed to experiment around the limits between natural and artificial, in other words, NATURAL PERVERSIONS. - A new road TOWARDS VIRTUAL ARCHITECTURE, to enable experiences with ambiance construction that are favored by technological advances derived from the control of perception. - MOVILITY AS AN OPTION FOR THE FUTURE, a response to the appearance of a new ever changing society, a bet on more flexible structures in all areas of architecture, from urban to domestic scale.

El muro como referencia arquitectónica

Esta investigación parte del interés particular por la manifestación arquitectónica, paisajística o urbanística de aquellos muros construidos que se han erigido para limitar, planteando un enfoque del muro en una vertiente conceptual. Se propone la formulación de distintas interpretaciones para un mismo elemento físico, logrando una propuesta arquitectónica de identificación para diferentes casos de estudio que consideramos paradigmáticos en su concepto. La hipótesis plantea la posibilidad de identificar un muro con la autonomía o identidad conceptual que le hace capaz de condicionar o dirigir la conformación de una obra de arquitectura, sirviendo como instrumento arquitectónico para las acciones de articulación, implantación, referenciación o conformación. El desarrollo de la investigación muestra la aptitud de individualizar el muro como elemento excepcional en el cumplimiento de la síntesis de distintas variables de proyecto. Se elaboran cinco conceptos diferentes del elemento en la función que cumple en el espacio que se basan en una definición compuesta de dos propiedades determinantes que se identifican con la categoría de la “justificación conceptual” combinando, además, valores de las categorías “Relación con el lugar”, “Función estética”, “Función de programa” y “Generación”. Se propone la identificación del muro que presenta las cualidades que lo hacen actuar de forma articuladora en el espacio y que, al cumplir esa función, condiciona y determina parte de la obra de arquitectura en que se encuentra. El muro articulador se entiende como un elemento que soluciona formal y espacialmente distintas situaciones de programa; no responde a un esquema formal predeterminado, sino que lo crea, en la unión coherente entre opuestos: ámbitos opuestos, esquemas formales opuestos, etc. Proponemos la identificación del muro que presenta determinadas cualidades que lo hacen actuar de forma implantadora en el espacio y que, al cumplir esa función, condiciona y determina parte de la obra en que se encuentra. Se considera el muro implantador como el punto de partida del proyecto en que se ha utilizado y como el elemento elegido para hacer la síntesis entre las variables del proyecto - sitio, función constructiva y estructural, estableciendo una regla formal y espacial coherente. Proponemos la identificación del muro referenciador, elemento que se destaca en la edificación como entidad elegida para hacer la síntesis entre las distintas variables del proyecto: significado, función estética y sitio. El muro referenciador se percibe como una entidad autónoma, particular al carácter o programa de la obra y al sitio en que se erige. Se considera el muro-recinto como el punto de partida del proyecto en que se ha utilizado, así como un elemento fundamental que se destaca en el conjunto de la obra - sea por su vertiente constructiva o de tratamiento estético – como entidad elegida para hacer la síntesis entre las variables del proyecto: forma y programa. Al utilizar un esquema formal predeterminado, permite generar espacio coherente con las demandas de un programa específico, entendiéndose como un elemento arquitectónico particular a la obra. Proponemos la identificación del muro habitable como el elemento que presenta las cualidades que lo hacen pasible de generar espacio en su interior, siendo un instrumento útil para cumplir con la variable del proyecto del programa. El concepto de muro habitable, como contrapunto a los otros cuatro tipos, se manifiesta como una entidad más elemental que traduce un instrumento de trabajo todavía más manejable que los restantes muros estudiados. De hecho, su utilización es incluso posible en aquellos muros que ya presentan el concepto de muro articulador, implantador, referenciador o muro-recinto. ABSTRACT This research is based on a particular interest in the architectural, landscape or urban manifestations of those walls that have been erected to limit, considering a conceptual approach. It suggests the formulation of diverse interpretations for the same physical element to achieve an architectural proposal of identification for different case studies that we consider paradigmatic in its concept. The hypothesis considers the possibility to identify a wall with the autonomy or conceptual identity that makes it able to influence or direct the form of an architecture work, serving as an instrument for the actions of articulation, emplacement, referencing or conformation. The development of the research shows the ability to individualize the wall as an outstanding element in the synthesis of different variables of architectural design. It elaborates five different concepts of the wall function in space, based on a definition with two determinant properties which combine values of the categories "Relation with the context", "Aesthetic function", "Program function" and "Generation". We propose the identification of the wall that has the qualities that make it act in an articulating way in space, conditioning and determining part of the architectural work. The “articulating wall” is understood as an element that formally and spatially solves different situations of functional program; it does not respond to a previous formal scheme, it creates it instead, through the coherent combination between opposites: opposing fields, opposing formal schemes, etc. We identify as well the wall that has the qualities that make it able to emplace on site, conditioning and determining part of the architecture work. The “wall that emplaces” is considered the starting point of the architectural design and the chosen element to make the synthesis between the architectural design variables - site, constructive function and structural function - establishing a formal and spatial coherent rule. We propose the identification of the “referencing wall”, element that stands out in the building as an entity chosen to make the synthesis between the project variables: meaning, aesthetic function and site. The referencing wall is perceived as an autonomous entity, particular to the character or the functional program and the site on which it sits. We consider the “precinct wall” as the departure point of the architectural design where it is used as well as a fundamental element that stands out in the whole of the architecture work - either by its constructive aspect or esthetic treatment - as the chosen entity to synthetize form and pro-gram. Since it uses a predetermined formal scheme it will allow to generate consistent space with-in the demands of a specific program, being understood as an element particular to the architectural work. As a fifth concept we identify the “inhabitable wall” as the element that has the qualities that make it predisposed to generate space inside its nucleus, being a useful instrument to comply with the variable of program in the architectural design. The concept of inhabitable wall, as a counterpoint to the other four types, manifests itself as a more elemental entity that translates itself as a more manageable working tool. In fact, its use is even possible in those walls that al-ready present the concept of articulating wall, emplacing wall, referencing wall or precinct wall.

Gestión intelectual de las prácticas comunicativas en arquitectura : S, M, L, XL, el gran evento = The intellectual management of communication practices in architecture : S, M, L, XL, the big event

La tesis doctoral se centra en la posibilidad de entender que la práctica de arquitectura puede encontrar en las prácticas comunicativas un apoyo instrumental, que sobrepasa cualquier simplificación clásica del uso de los medios como una mera aplicación superficial, post-producida o sencillamente promocional. A partir de esta premisa se exponen casos del último cuarto del siglo XX y se detecta que amenazas como el riesgo de la banalización, la posible saturación de la imagen pública o la previsible asociación incorrecta con otros individuos en presentaciones grupales o por temáticas, han podido influir en un crecimiento notable de la adquisición de control, por parte de los arquitectos, en sus oportunidades mediáticas. Esto es, como si la arquitectura hubiera empezado a superar y optimizar algo inevitable, que las fórmulas expositivas y las publicaciones, o más bien del exponer(se) y publicar(se), son herramientas disponibles para activar algún tipo de gestión intelectual de la comunicación e información circulante sobre si misma. Esta práctica de “autoedición” se analiza en un periodo concreto de la trayectoria de OMA -Office for Metropolitan Architecture-, estudio considerado pionero en el uso eficiente, oportunista y personalizado de los medios. Así, la segunda parte de la tesis se ocupa del análisis de su conocida monografía S,M,L,XL (1995), un volumen que contó con gran participación por parte de sus protagonistas durante la edición, y de cuyo proceso de producción apenas se había investigado. Esta publicación señaló un punto de inflexión en su género alterando todo formato y restricciones anteriores, y se ha convertido en un volumen emblemático para la disciplina que ninguna réplica posterior ha podido superar. Aquí se presenta a su vez como el desencadenante de la construcción de un “gran evento” que concluye en la transformación de la identidad de OMA en 10 años, paradójicamente entre el nacimiento de la Fundación Groszstadt y el arranque de la actividad de AMO, dos entidades paralelas clave anexas a OMA. Este planteamiento deviene de cómo la investigación desvela que S,M,L,XL es una pieza más, central pero no independiente, dentro de una suma de acciones e individuos, así como otras publicaciones, exposiciones, eventos y también artículos ensayados y proyectos, en particular Bigness, Generic City, Euralille y los concursos de 1989. Son significativos aspectos como la apertura a una autoría múltiple, encabezada por Rem Koolhaas y el diseñador gráfico Bruce Mau, acompañados en los agradecimientos de la editora Jennifer Sigler y cerca de una centena de nombres, cuyas aportaciones no necesariamente se basan en la construcción de fragmentos del libro. La supresión de ciertos límites permite superar también las tareas inicialmente relevantes en la edición de una publicación. Un objetivo general de la tesis es también la reflexión sobre relaciones anteriormente cuestionadas, como la establecida entre la arquitectura y los mercados o la economía. Tomando como punto de partida la idea de “design intelligence” sugerida por Michael Speaks (2001), se extrae de sus argumentos que lo esencial es el hallazgo de la singularidad o inteligencia propia de cada estudio de arquitectura o diseño. Asimismo se explora si en la construcción de ese tipo de fórmulas magistrales se alojaban también combinaciones de interés y productivas entre asuntos como la eficiencia y la creatividad, o la organización y las ideas. En esta dinámica de relaciones bidireccionales, y en ese presente de exceso de información, se fundamenta la propuesta de una equivalencia más evidenciada entre la “socialización” del trabajo del arquitecto, al compartirlo públicamente e introducir nuevas conversaciones, y la relación inversa a partir del trabajo sobre la “socialización” misma. Como si la consciencia sobre el uso de los medios pudiera ser efectivamente instrumental, y contribuir al desarrollo de la práctica de arquitectura, desde una perspectiva idealmente comprometida e intelectual. ABSTRACT The dissertation argues the possibility to understand that the practice of architecture can find an instrumental support in the practices of communication, overcoming any classical simplification of the use of media, generally reduced to superficial treatments or promotional efforts. Thus some cases of the last decades of the 20th century are presented. Some threats detected, such as the risk of triviality, the saturation of the public image or the foreseeable wrong association among individuals when they are introduced as part of thematic groups, might have encouraged a noticeable increase of command taken by architects when there is chance to intervene in a media environment. In other words, it can be argued that architecture has started to overcome and optimize the inevitable, the fact that exhibition formulas and publications, or simply the practice of (self)exhibition or (self)publication, are tools at our disposal for the activation of any kind of intellectual management of communication and circulating information about itself. This practice of “self-edition” is analyzed in a specific timeframe of OMA’s trajectory, an office that is considered as a ground-breaking actor in the efficient and opportunistic use of media. Then the second part of the thesis dissects their monograph S,M,L,XL (1995), a volume in which its main characters were deeply involved in terms of edition and design, a process barely analyzed up to now. This publication marked a turning point in its own genre, disrupting old formats and traditional restrictions. It became such an emblematic volume for the discipline that none of the following attempts of replica has ever been able to improve this precedent. Here, the book is also presented as the element that triggers the construction of a “big event” that concludes in the transformation of OMA identity in 10 years. Paradoxically, between the birth of the Groszstadt Foundation and the early steps of AMO, both two entities parallel and connected to OMA. This positions emerge from how the research unveils that S,M,L,XL is one more piece, a key one but not an unrelated element, within a sum of actions and individuals, as well as other publications, exhibitions, articles and projects, in particular Bigness, Generic City, Euralille and the competitions of 1989. Among the remarkable innovations of the monograph, there is an outstanding openness to a regime of multiple authorship, headed by Rem Koolhaas and the graphic designer Bruce Mau, who share the acknowledgements page with the editor, Jennifer Sigler, and almost 100 people, not necessarily responsible for specific fragments of the book. In this respect, the dissolution of certain limits made possible that the expected tasks in the edition of a publication could be trespassed. A general goal of the thesis is also to open a debate on typically questioned relations, particularly between architecture and markets or economy. Using the idea of “design intelligence”, outlined by Michael Speaks in 2001, the thesis pulls out its essence, basically the interest in detecting the singularity, or particular intelligence of every office of architecture and design. Then it explores if in the construction of this kind of ingenious formulas one could find interesting and useful combinations among issues like efficiency and creativity, or organization and ideas. This dynamic of bidirectional relations, rescued urgently at this present moment of excess of information, is based on the proposal for a more evident equivalence between the “socialization” of the work in architecture, anytime it is shared in public, and the opposite concept, the work on the proper act of “socialization” itself. As if a new awareness of the capacities of the use of media could turn it into an instrumental force, capable of contributing to the development of the practice of architecture, from an ideally committed and intelectual perspective.

Casas de la oligarquía castellana en la Granada del siglo XVI : tipologías, adaptación y contexto urbano, fundamentos para su recuperación

El tema de estudio de esta tesis es el análisis morfológico y cronológico de diez ejemplares emblemáticos de la arquitectura doméstica señorial de la Granada del siglo XVI, analizados en comparación con otros casos de referencia construidos en el mismo período en la propia ciudad, conservados y desaparecidos. También se han tenido en cuenta las principales manifestaciones arquitectónicas de los mayores focos urbanos contemporáneos en el reino de Castilla. El trabajo se ha desarrollado partiendo de la realización de una planimetría precisa y completa de las diez casas documentadas, uniendo al trabajo in situ sobre los datos materiales el estudio de las fuentes de archivo y de la bibliografía especializada existente sobre la materia. El análisis formal de las unidades domésticas ha sido enfocado al estudio tipológico de lo construido, haciendo especial hincapié en las pervivencias andalusíes sobre las cuales los nuevos moradores edificaron o adaptaron sus casas solariegas. En apoyo a las hipótesis presentadas se aporta la documentación arqueológica derivada de las excavaciones realizadas en los solares de las viviendas objeto de análisis, además de los planos de los estados previos a las recientes reformas sufridas por muchos de estos edificios. El análisis comparativo con algunos edificios contemporáneos en los que se ha documentado y estudiado cronológicamente su evolución histórica, ha permitido afianzar las hipótesis de datación y de reconstrucción de la distribución espacial de las fábricas originarias de la época tratada. Los objetivos de la investigación han sido orientados a poner de manifiesto la delicada y compleja transición de la medina nazarí a la ciudad cristiana, tratando también ciertas características multiculturales propias de las técnicas constructivas y de sociedad de la época. Los resultados de este estudio multidisciplinar se han registrado en un mapa de datos creado con el Sistema de Información Geográfico, en el que se han incluido tanto los datos cronológicos como formales, individualizando los ambientes que constituyen las pervivencias medievales y los que se han construido después, aportando sus distintas dataciones. Se ha querido dar respuesta a varios interrogativos: ¿Cómo se adapta la arquitectura castellana al tejido urbano andalusí? ¿Reaprovecha las preexistencias o las elimina en cada momento? ¿De qué modo la ciudad ha ido modificándose hasta configurarse como una ciudad moderna? ¿Cuánto se ha mantenido este patrimonio de casas? ¿Cómo se debería conservar? Se ha tratado de resolver estas cuestiones formulando síntesis gráficas en las que se puede comprender la evolución histórica de las viviendas acontecida a lo largo del siglo XVI, junto con sus transformaciones recientes provocadas por las intervenciones contemporáneas. Asimismo se aporta el estudio de las principales características de las intervenciones acometidas sobre este patrimonio único de viviendas, que por su propia naturaleza es altamente perecedero y necesita que se formulen criterios eficaces y correctos para su mayor conservación. El punto de partida de este trabajo no ha sido solamente el análisis de campo sino también la recopilación y ordenación de los datos procedentes de la bibliografía existente para formular discursos coherentes y precisos sobre la evolución de este tipo de viviendas históricas, cuyos valores son tan expuestos a graves deterioros que su catalogación, documentación y valoración se hacen imprescindibles. Pese a que las diez viviendas incluidas en los capítulos de estudio detallado estén catalogadas en los Planes Especiales de Protección (Albaicín, 1990 y Centro, 2002), sus caracteres formales y sus elementos estructurales y decorativos de valor histórico han sufrido un evidente proceso de expolio o destrucción, hecho grave que esta Tesis quiere reflejar de cara a la deseable futura puesta en valor real de estos edificios así como, indirectamente, de sus ámbitos urbanísticos de pertenencia. ABSTRACT The purpose of this thesis is to study the morphological and chronological characteristics of ten emblematic mansions belonging to the architectural period of the 16th Century in Granada, Spain. These houses are compared with other similar outstanding constructions of the same period that are located in the city, which have either been preserved or disappeared. Also, this study has taken into account the main architectural expressions of greater contemporary urban areas of the Kingdom of Castile. The work carried out began, first of all, by drawing a precise and thorough planimetry of the ten surveyed houses, together with in situ tasks based on physical data, a study of archival data, and the specialized existing bibliography on the subject. The formal analysis of the home units is focused as a typological study of erected buildings, with a special attention on Al Andalus remains over which the new householders constructed or adapted their mansions. The hypotheses brought forward have been supported by the archaeological documentation that had been elaborated during the excavation works of the houses concerned in this study. Moreover, the drawings of the states of the sites, previously to the most recent renovation works many of these buildings have undergone, have been presented. The comparative analysis made with some contemporary buildings, which have been chronologically documented and studied in their historical evolution, has confirmed the dating hypotheses, and that of the reconstruction of the spatial distribution of the original factories the period discussed. The aims of this research have been oriented to bring to light the delicate and complex transition of the town, from the Nasrid period to Christian times. The research has also dealt with some special multicultural characteristics of the constructive techniques, as well as of the society of that period. The results of this multidisciplinary study have been registered on a data map created with the Geographical Information System, which includes both the chronological and formal data. The Medieval settings, and those of later constructions, have been individualised and dated. Several questions have been answered: how the Castilian architecture adapts to the Al Andalus urban design? Have the pre-existing structures been reused or eliminated at each stage? How has the town evolved until becoming a modern city? To which degree this heritage of houses has remained? How should it been preserved? These questions have been approached by means of graphical syntheses in an attempt to bring an understanding of the historical evolution of the houses throughout the 16th Century. But also, this work shows the more recent transformations these structures suffered over the contemporary period. Moreover, there is a study of the main characteristics of interventions over this unique patrimony of housing which by nature is perishable and needs a formulation of correct and efficient criteria for better conservation. The starting point of this work has not only been that of field analysis, but also the gathering and ordering of the existing bibliographical data, in order to formulate coherent and precise statements on the evolution of this type of historical housing. Its treasures are so exposed to severe deterioration that their cataloguing, documentation and appreciation are becoming crucial. Despite the fact that the ten houses considered in the chapters of this detailed study are listed in the special protection plans (Planes Especiales de Protección, Albaicín plan of 1990 and the town centre plan of 2002) their formal characteristics, as well as structural and decorative historical value, have suffered gradual plunders or destruction. This thesis tries to reflect how serious is that matter and the need in the future to give this heritage and the surrounding urban environment, a real value.

Carolyn Banner

Carolyn had a Bachelor of Science in Education degree from Langston University and a Master of Science degree in Early Childhood Development from the University of Minnesota. In 1959 Carolyn came to Lincoln as acting principal of the laboratory Elementary School and Supervisor of Elementary Student Teaching. She nurtured and taught hundreds of Lincoln’s students to be the finest, most qualified teachers in the country. Once retired she was able to enjoy the many awards that she received through out her years. The awards she received were citations, and honors: AAUW Woman of Achievement Award, and the MUATE Outstanding Teacher Educator Award. She was elected the first Black President of AAUW in 1965. She was appointed to the Mayor’s Census and Redistricting Committee in 1981. On June 21st, 1985 Mayor George Hartsfield declared that day as “Carolyn Banner Day” in Jefferson City. Carolyn Banner retired from Lincoln University in July 1985.

NADH-quinone oxidoreductase: PSST subunit couples electron transfer from iron–sulfur cluster N2 to quinone

The proton-translocating NADH-quinone oxidoreductase (EC 1.6.99.3) is the largest and least understood enzyme complex of the respiratory chain. The mammalian mitochondrial enzyme (also called complex I) contains more than 40 subunits, whereas its structurally simpler bacterial counterpart (NDH-1) in Paracoccus denitrificans and Thermus thermophilus HB-8 consists of 14 subunits. A major unsolved question is the location and mechanism of the terminal electron transfer step from iron–sulfur cluster N2 to quinone. Potent inhibitors acting at this key region are candidate photoaffinity probes to dissect NADH-quinone oxidoreductases. Complex I and NDH-1 are very sensitive to inhibition by a variety of structurally diverse toxicants, including rotenone, piericidin A, bullatacin, and pyridaben. We designed (trifluoromethyl)diazirinyl[3H]pyridaben ([3H]TDP) as our photoaffinity ligand because it combines outstanding inhibitor potency, a suitable photoreactive group, and tritium at high specific activity. Photoaffinity labeling of mitochondrial electron transport particles was specific and saturable. Isolation, protein sequencing, and immunoprecipitation identified the high-affinity specifically labeled 23-kDa subunit as PSST of complex I. Immunoprecipitation of labeled membranes of P. denitrificans and T. thermophilus established photoaffinity labeling of the equivalent bacterial NQO6. Competitive binding and enzyme inhibition studies showed that photoaffinity labeling of the specific high-affinity binding site of PSST is exceptionally sensitive to each of the high-potency inhibitors mentioned above. These findings establish that the homologous PSST of mitochondria and NQO6 of bacteria have a conserved inhibitor-binding site and that this subunit plays a key role in electron transfer by functionally coupling iron–sulfur cluster N2 to quinone.

Fipronil insecticide: Novel photochemical desulfinylation with retention of neurotoxicity

Fipronil is an outstanding new insecticide for crop protection with good selectivity between insects and mammals. The insecticidal action involves blocking the γ-aminobutyric acid-gated chloride channel with much greater sensitivity of this target in insects than in mammals. Fipronil contains a trifluoromethylsulfinyl moiety that is unique among the agrochemicals and therefore presumably important in its outstanding performance. We find that this substituent unexpectedly undergoes a novel and facile photoextrusion reaction on plants upon exposure to sunlight, yielding the corresponding trifluoromethylpyrazole, i.e., the desulfinyl derivative. The persistence of this photoproduct and its high neuroactivity, resulting from blocking the γ-aminobutyric acid-gated chloride channel, suggest that it may be a significant contributor to the effectiveness of fipronil. In addition, desulfinylfipronil is not a metabolite in mammals, so the safety evaluations must take into account not only the parent compound but also this completely new environmental product.

Rapid chemical kinetic techniques for investigations of neurotransmitter receptors expressed in Xenopus oocytes

Xenopus laevis oocytes have been used extensively during the past decade to express and study neurotransmitter receptors of various origins and subunit composition and also to express and study receptors altered by site-specific mutations. Interpretations of the effects of structural differences on receptor mechanisms were, however, hampered by a lack of rapid chemical reaction techniques suitable for use with oocytes. Here we describe flow and photolysis techniques, with 2-ms and 100-μs time resolution, respectively, for studying neurotransmitter receptors in giant (≈20-μm diameter) patches of oocyte membranes, using muscle and neuronal acetylcholine receptors as examples. With these techniques, we find that the muscle receptor in BC3H1 cells and the same receptor expressed in oocytes have comparable kinetic properties. This finding is in contrast to previous studies and raises questions regarding the interpretations of the many studies of receptors expressed in oocytes in which an insufficient time resolution was available. The results obtained indicate that the rapid reaction techniques described here, in conjunction with the oocyte expression system, will be useful in answering many outstanding questions regarding the structure and function of diverse neurotransmitter receptors.

Stomatal plugs of Drimys winteri (Winteraceae) protect leaves from mist but not drought

Two outstanding features of the flowering plant family Winteraceae are the occlusion of their stomatal pores by cutin plugs and the absence of water-conducting xylem vessels. An adaptive relationship between these two unusual features has been suggested whereby stomatal plugs restrict gas exchange to compensate for the presumed poor conductivity of their vesselless wood. This hypothesized connection fueled evolutionary arguments that the vesselless condition is ancestral in angiosperms. Here we show that in Drimys winteri, a tree common to wet forests, these stomatal occlusions pose only a small fixed resistance to water loss. In addition, they modify the humidity response of guard cells such that under high evaporative demand, leaves with plugs lose water at a faster rate than leaves from which the plugs have been experimentally removed. Instead of being adaptations for drought, we present evidence that these cuticular structures function to maintain photosynthetic activity under conditions of excess water on the leaf surface. Stomatal plugs decrease leaf wettability by preventing the formation of a continuous water film that would impede diffusion of CO2 into the leaf. Misting of leaves had no effect on photosynthetic rate of leaves with plugs, but resulted in a marked decrease (≈40%) in leaves from which the plugs had been removed. These findings do not support a functional association between stomatal plugs and hydraulic competence and provide a new perspective on debates surrounding the evolution of vessels in angiosperms.

Molecular mechanisms underlying differential odor responses of a mouse olfactory receptor

The prevailing paradigm for G protein-coupled receptors is that each receptor is narrowly tuned to its ligand and closely related agonists. An outstanding problem is whether this paradigm applies to olfactory receptor (ORs), which is the largest gene family in the genome, in which each of 1,000 different G protein-coupled receptors is believed to interact with a range of different odor molecules from the many thousands that comprise “odor space.” Insights into how these interactions occur are essential for understanding the sense of smell. Key questions are: (i) Is there a binding pocket? (ii) Which amino acid residues in the binding pocket contribute to peak affinities? (iii) How do affinities change with changes in agonist structure? To approach these questions, we have combined single-cell PCR results [Malnic, B., Hirono, J., Sato, T. & Buck, L. B. (1999) Cell 96, 713–723] and well-established molecular dynamics methods to model the structure of a specific OR (OR S25) and its interactions with 24 odor compounds. This receptor structure not only points to a likely odor-binding site but also independently predicts the two compounds that experimentally best activate OR S25. The results provide a mechanistic model for olfactory transduction at the molecular level and show how the basic G protein-coupled receptor template is adapted for encoding the enormous odor space. This combined approach can significantly enhance the identification of ligands for the many members of the OR family and also may shed light on other protein families that exhibit broad specificities, such as chemokine receptors and P450 oxidases.

Genetics and the origin of bird species

External (environmental) factors affecting the speciation of birds are better known than the internal (genetic) factors. The opposite is true for several groups of invertebrates, Drosophila being the outstanding example. Ideas about the genetics of speciation in general trace back to Dobzhansky who worked with Drosophila. These ideas are an insufficient guide for reconstructing speciation in birds for two main reasons. First, speciation in birds proceeds with the evolution of behavioral barriers to interbreeding; postmating isolation usually evolves much later, perhaps after gene exchange has all but ceased. As a consequence of the slow evolution of postmating isolating factors the scope for reinforcement of premating isolation is small, whereas the opportunity for introgressive hybridization to influence the evolution of diverging species is large. Second, premating isolation may arise from nongenetic, cultural causes; isolation may be affected partly by song, a trait that is culturally inherited through an imprinting-like process in many, but not all, groups of birds. Thus the genetic basis to the origin of bird species is to be sought in the inheritance of adult traits that are subject to natural and sexual selection. Some of the factors involved in premating isolation (plumage, morphology, and behavior) are under single-gene control, most are under polygenic control. The genetic basis of the origin of postmating isolating factors affecting the early development of embryos (viability) and reproductive physiology (sterility) is almost completely unknown. Bird speciation is facilitated by small population size, involves few genetic changes, and occurs relatively rapidly.