The role of the secondary cell wall in plant resistance to pathogens

Plant resistance to pathogens relies on a complex network of constitutive and inducible defensive barriers. The plant cell wall is one of the barriers that pathogens need to overcome to successfully colonize plant tissues. The traditional view of the plant cell wall as a passive barrier has evolved to a concept that considers the wall as a dynamic structure that regulates both constitutive and inducible defense mechanisms, and as a source of signaling molecules that trigger immune responses. The secondary cell walls of plants also represent a carbon-neutral feedstock (lignocellulosic biomass) for the production of biofuels and biomaterials. Therefore, engineering plants with improved secondary cell wall characteristics is an interesting strategy to ease the processing of lignocellulosic biomass in the biorefinery. However, modification of the integrity of the cell wall by impairment of proteins required for its biosynthesis or remodeling may impact the plants resistance to pathogens. This review summarizes our understanding of the role of the plant cell wall in pathogen resistance with a focus on the contribution of lignin to this biological process.

Functional characterization of YODA, a mitogen-activated protein kinase kinase kinase (MAP3K) that regulates a novel innate immunity pathway in Arabidopsis thaliana

Las cascadas de señalización mediadas por proteína quinasas activadas por mitógeno (MAP quinasas) son capaces de integrar y transducir señales ambientales en respuestas celulares. Entre estas señales se encuentran los PAMPs/MAMPs (Pathogen/Microbe-Associated Molecular Patterns), que son moléculas de patógenos o microorganismos, o los DAMPs (Damaged-Associated Molecular Patterns), que son moléculas derivadas de las plantas producidas en respuesta a daño celular. Tras el reconocimiento de los PAMPs/DAMPs por receptores de membrana denominados PRRs (Pattern Recognition Receptors), como los receptores con dominio quinasa (RLKs) o los receptores sin dominio quinasa (RLPs), se activan respuestas moleculares, incluidas cascadas de MAP quinasas, que regulan la puesta en marcha de la inmunidad activada por PAMPs (PTI). Esta Tesis describe la caracterización funcional de la MAP quinasa quinasa quinasa (MAP3K) YODA (YDA), que actúa como un regulador clave de la PTI en Arabidopsis. Se ha descrito previamente que YDA controla varios procesos de desarrollo, como la regulación del patrón estomático, la elongación del zigoto y la arquitectura floral. Hemos caracterizado un alelo mutante hipomórfico de YDA (elk2 o yda11) que presenta una elevada susceptibilidad a patógenos biótrofos y necrótrofos. Notablemente, plantas que expresan una forma constitutivamente activa de YDA (CA-YDA), con una deleción en el dominio N-terminal, presentan una resistencia de amplio espectro frente a diferentes tipos de patógenos, incluyendo hongos, oomicetos y bacterias, lo que indica que YDA juega un papel importante en la regulación de la resistencia de las plantas a patógenos. Nuestros datos indican que esta función es independiente de las respuestas inmunes mediadas por los receptores previamente caracterizados FLS2 y CERK1, que reconocen los PAMPs flg22 y quitina, respectivamente, y que están implicados en la resistencia de Arabidopsis frente a bacterias y hongos. Hemos demostrado que YDA controla la resistencia frente al hongo necrótrofo Plectosphaerella cucumerina y el patrón estomático mediante su interacción genética con la RLK ERECTA (ER), un PRR implicado en la regulación de estos procesos. Por el contrario, la interacción genética entre ER y YDA en la regulación de otros procesos de desarrollo es aditiva en lugar de epistática. Análisis genéticos indicaron que MPK3, una MAP quinasa que funciona aguas abajo de YDA en el desarrollo estomático, es un componente de la ruta de señalización mediada por YDA para la resistencia frente a P. cucumerina, lo que sugiere que el desarrollo de las plantas y la PTI comparten el módulo de transducción de MAP quinasas asociado a YDA. Nuestros experimentos han revelado que la resistencia mediada por YDA es independiente de las rutas de señalización reguladas por las hormonas de defensa ácido salicílico, ácido jasmónico, ácido abscísico o etileno, y también es independiente de la ruta de metabolitos secundarios derivados del triptófano, que están implicados en inmunidad vegetal. Además, hemos demostrado que respuestas asociadas a PTI, como el aumento en la concentración de calcio citoplásmico, la producción de especies reactivas de oxígeno, la fosforilación de MAP quinasas y la expresión de genes de defensa, no están afectadas en el mutante yda11. La expresión constitutiva de la proteína CA-YDA en plantas de Arabidopsis no provoca un aumento de las respuestas PTI, lo que sugiere la existencia de mecanismos de resistencia adicionales regulados por YDA que son diferentes de los regulados por FLS2 y CERK1. En línea con estos resultados, nuestros datos transcriptómicos revelan una sobre-representación en plantas CA-YDA de genes de defensa que codifican, por ejemplo, péptidos antimicrobianos o reguladores de muerte celular, o proteínas implicadas en la biogénesis de la pared celular, lo que sugiere una conexión potencial entre la composición e integridad de la pared celular y la resistencia de amplio espectro mediada por YDA. Además, análisis de fosfoproteómica indican la fosforilación diferencial de proteínas relacionadas con la pared celular en plantas CA-YDA en comparación con plantas silvestres. El posible papel de la ruta ER-YDA en la regulación de la integridad de la pared celular está apoyado por análisis bioquímicos y glicómicos de las paredes celulares de plantas er, yda11 y CA-YDA, que revelaron cambios significativos en la composición de la pared celular de estos genotipos en comparación con la de plantas silvestres. En resumen, nuestros datos indican que ER y YDA forman parte de una nueva ruta de inmunidad que regula la integridad de la pared celular y respuestas defensivas, confiriendo una resistencia de amplio espectro frente a patógenos. ABSTRACT Plant mitogen-activated protein kinase (MAPK) cascades transduce environmental signals and developmental cues into cellular responses. Among these signals are the pathogen- or microbe-associated molecular patterns (PAMPs or MAMPs) and the damage-associated molecular patterns (DAMPs). These PAMPs/DAMPs, upon recognition by plant pattern recognition receptors (PRRs), such as Receptor-Like Kinases (RLKs) and Receptor-Like Proteins (RLPs), activate molecular responses, including MAPK cascades, which regulate the onset of PAMP-triggered immunity (PTI). This Thesis describes the functional characterization of the MAPK kinase kinase (MAP3K) YODA (YDA) as a key regulator of Arabidopsis PTI. YDA has been previously described to control several developmental processes, such as stomatal patterning, zygote elongation and inflorescence architecture. We characterized a hypomorphic, non-embryo lethal mutant allele of YDA (elk2 or yda11) that was found to be highly susceptible to biotrophic and necrotrophic pathogens. Remarkably, plants expressing a constitutive active form of YDA (CA-YDA), with a deletion in the N-terminal domain, showed broad-spectrum resistance to different types of pathogens, including fungi, oomycetes and bacteria, indicating that YDA plays a relevant function in plant resistance to pathogens. Our data indicated that this function is independent of the immune responses regulated by the well characterized FLS2 and CERK1 RLKs, which are the PRRs recognizing flg22 and chitin PAMPs, respectively, and are required for Arabidopsis resistance to bacteria and fungi. We demonstrate that YDA controls resistance to the necrotrophic fungus Plectosphaerella cucumerina and stomatal patterning by genetically interacting with ERECTA (ER) RLK, a PRR involved in regulating these processes. In contrast, the genetic interaction between ER and YDA in the regulation of other ER-associated developmental processes was additive, rather than epistatic. Genetic analyses indicated that MPK3, a MAP kinase that functions downstream of YDA in stomatal development, also regulates plant resistance to P. cucumerina in a YDA-dependent manner, suggesting that the YDA-associated MAPK transduction module is shared in plant development and PTI. Our experiments revealed that YDA-mediated resistance was independent of signalling pathways regulated by defensive hormones like salicylic acid, jasmonic acid, abscisic acid or ethylene, and of the tryptophan-derived metabolites pathway, which are involved in plant immunity. In addition, we showed that PAMP-mediated PTI responses, such as the increase of cytoplasmic Ca2+ concentration, reactive oxygen species (ROS) burst, MAPK phosphorylation, and expression of defense-related genes are not impaired in the yda11 mutant. Furthermore, the expression of CA-YDA protein does not result in enhanced PTI responses, further suggesting the existence of additional mechanisms of resistance regulated by YDA that differ from those regulated by the PTI receptors FLS2 and CERK1. In line with these observations, our transcriptomic data revealed the over-representation in CA-YDA plants of defensive genes, such as those encoding antimicrobial peptides and cell death regulators, and genes encoding cell wall-related proteins, suggesting a potential link between plant cell wall composition and integrity and broad spectrum resistance mediated by YDA. In addition, phosphoproteomic data revealed an over-representation of genes encoding wall-related proteins in CA-YDA plants in comparison with wild-type plants. The putative role of the ER-YDA pathway in regulating cell wall integrity was further supported by biochemical and glycomics analyses of er, yda11 and CA-YDA cell walls, which revealed significant changes in the cell wall composition of these genotypes compared with that of wild-type plants. In summary, our data indicate that ER and YDA are components of a novel immune pathway that regulates cell wall integrity and defensive responses, which confer broad-spectrum resistance to pathogens.

Functional response of Ulmus minor Mill. to drought, flooding and dutch elm disease

Ulmus minor es una especie arbórea originaria de Europa cuyas poblaciones han sido diezmadas por el hongo patógeno causante de la enfermedad de la grafiosis. La conservación de los olmos exige plantearse su propagación a través de plantaciones y conocer mejor su ecología y biología. Ulmus minor es un árbol de ribera, pero frecuentemente se encuentra alejado del cauce de arroyos y ríos, donde la capa freática sufre fuertes oscilaciones. Por ello, nuestra hipótesis general es que esta especie es moderadamente resistente tanto a la inundación como a la sequía. El principal objetivo de esta tesis doctoral es entender desde un punto de vista funcional la respuesta de U. minor a la inundación, la sequía y la infección por O. novo-ulmi; los factores que posiblemente más influyen en la distribución actual de U. minor. Con este objetivo se persigue dar continuidad a los esfuerzos de conservación de esta especie que desde hace años se dedican en varios centros de investigación a nivel mundial, ya que, entender mejor los mecanismos que contribuyen a la resistencia de U. minor ante la inoculación con O. novo-ulmi y factores de estrés abiótico ayudará en la selección y propagación de genotipos resistentes a la grafiosis. Se han planteado tres experimentos en este sentido. Primero, se ha comparado la tolerancia de brinzales de U. minor y U. laevis – otro olmo ibérico – a una inmersión controlada con el fin de evaluar su tolerancia a la inundación y comprender los mecanismos de aclimatación. Segundo, se ha comparado la tolerancia de brinzales de U. minor y Quercus ilex – una especie típica de ambientes Mediterránea secos – a la falta de agua en el suelo con el fin de evaluar el grado de tolerancia y los mecanismos de aclimatación a la sequía. El hecho de comparar dos especies contrastadas responde al interés en entender mejor cuales son los procesos que conducen a la muerte de una planta en condiciones de sequía – asunto sobre el que hay una interesante discusión desde hace algunos años. En tercer lugar, con el fin de entender mejor la resistencia de algunos genotipos de U. minor a la grafiosis, se han estudiado las diferencias fisiológicas y químicas constitutivas e inducidas por O. novo-ulmi entre clones de U. minor seleccionados a priori por su variable grado de resistencia a esta enfermedad. En el primer experimento se observó que los brinzales de U. minor sobrevivieron 60 días inmersos en una piscina con agua no estancada hasta una altura de 2-3 cm por encima del cuello de la raíz. A los 60 días, los brinzales de U. laevis se sacaron de la piscina y, a lo largo de las siguientes semanas, fueron capaces de recuperar las funciones fisiológicas que habían sido alteradas anteriormente. La conductividad hidráulica de las raíces y la tasa de asimilación de CO2 neta disminuyeron en ambas especies. Por el contrario, la tasa de respiración de hojas, tallos y raíces aumentó en las primeras semanas de la inundación, posiblemente en relación al aumento de energía necesario para desarrollar mecanismos de aclimatación a la inundación, como la hipertrofia de las lenticelas que se observó en ambas especies. Por ello, el desequilibrio del balance de carbono de la planta podría ser un factor relevante en la mortalidad de las plantas ante inundaciones prolongadas. Las plantas de U. minor (cultivadas en envases de 16 litros a media sombra) sobrevivieron por un prolongado periodo de tiempo en verano sin riego; la mitad de las plantas murieron tras 90 días sin riego. El cierre de los estomas y la pérdida de hojas contribuyeron a ralentizar las pérdidas de agua y tolerar la sequía en U. minor. Las obvias diferencias en tolerancia a la sequía con respecto a Q. ilex se reflejaron en la distinta capacidad para ralentizar la aparición del estrés hídrico tras dejar de regar y para transportar agua en condiciones de elevada tensión en el xilema. Más relevante es que las plantas con evidentes síntomas de decaimiento previo a su muerte exhibieron pérdidas de conductividad hidráulica en las raíces del 80% en ambas especies, mientras que las reservas de carbohidratos apenas variaron y lo hicieron de forma desigual en ambas especies. Árboles de U. minor de 5 y 6 años de edad (plantados en eras con riego mantenido) exhibieron una respuesta a la inoculación con O. novo-ulmi consistente con ensayos previos de resistencia. La conductividad hidráulica del tallo, el potencial hídrico foliar y la tasa de asimilación de CO2 neta disminuyeron significativamente en relación a árboles inoculados con agua, pero solo en los clones susceptibles. Este hecho enlaza con el perfil químico “más defensivo” de los clones resistentes, es decir, con los mayores niveles de suberina, ácidos grasos y compuestos fenólicos en estos clones que en los susceptibles. Ello podría restringir la propagación del hongo en el árbol y preservar el comportamiento fisiológico de los clones resistentes al inocularlos con el patógeno. Los datos indican una respuesta fisiológica común de U. minor a la inundación, la sequía y la infección por O. novo-ulmi: pérdida de conductividad hidráulica, estrés hídrico y pérdida de ganancia neta de carbono. Pese a ello, U. minor desarrolla varios mecanismos que le confieren una capacidad moderada para vivir en suelos temporalmente anegados o secos. Por otro lado, el perfil químico es un factor relevante en la resistencia de ciertos genotipos a la grafiosis. Futuros estudios deberían examinar como este perfil químico y la resistencia a la grafiosis se ven alteradas por el estrés abiótico. ABSTRACT Ulmus minor is a native European elm species whose populations have been decimated by the Dutch elm disease (DED). An active conservation of this species requires large-scale plantations and a better understanding of its biology and ecology. U. minor generally grows close to water channels. However, of the Iberian riparian tree species, U. minor is the one that spread farther away from rivers and streams. For these reasons, we hypothesize that this species is moderately tolerant to both flooding and drought stresses. The main aim of the present PhD thesis is to better understand the functional response of U. minor to the abiotic stresses – flooding and drought – and the biotic stress – DED – that can be most influential on its distribution. The overarching goal is to aid in the conservation of this emblematic species through a better understanding of the mechanisms that contribute to resistance to abiotic and biotic stresses; an information that can help in the selection of resistant genotypes and their expansion in large-scale plantations. To this end, three experiments were set up. First, we compared the tolerance to experimental immersion between seedlings of U. minor and U. laevis – another European riparian elm species – in order to assess their degree of tolerance and understand the mechanisms of acclimation to this stress. Second, we investigated the tolerance to drought of U. minor seedlings in comparison with Quercus ilex (an oak species typical of dry Mediterranean habitats). Besides assessing and understanding U. minor tolerance to drought at the seedling stage, the aim was to shed light into the functional alterations that trigger drought-induced plant mortality – a matter of controversy in the last years. Third, we studied constitutive and induced physiological and biochemical differences among clones of variable DED resistance, before and following inoculation with Ophiostoma novo-ulmi. The goal is to shed light into the factors of DED resistance that is evident in some genotypes of U. minor, but not others. Potted seedlings of U. minor survived for 60 days immersed in a pool with running water to approximately 2-3 cm above the stem collar. By this time, U. minor seedlings died, whereas U. laevis seedlings moved out of the pool were able to recover most physiological functions that had been altered by flooding. For example, root hydraulic conductivity and leaf photosynthetic CO2 uptake decreased in both species; while respiration initially increased with flooding in leaves, stems and roots possibly to respond to energy demands associated to mechanisms of acclimation to soil oxygen deficiency; as example, a remarkable hypertrophy of lenticels was soon observed in flooded seedlings of both species. Therefore, the inability to maintain a positive carbon balance somehow compromises seedling survival under flooding, earlier in U. minor than U. laevis, partly explaining their differential habitats. Potted seedlings of U. minor survived for a remarkable long time without irrigation – half of plants dying only after 90 days of no irrigation in conditions of high vapour pressure deficit typical of summer. Some mechanisms that contributed to tolerate drought were leaf shedding and stomata closure, which reduced water loss and the risk of xylem cavitation. Obviously, U. minor was less tolerant to drought than Q. ilex, differences in drought tolerance resulting mostly from the distinct capacity to postpone water stress and conduct water under high xylem tension among species. More relevant was that plants of both species exhibited similar symptoms of root hydraulic failure (i.e. approximately 80% loss of hydraulic conductivity), but a slight and variable depletion of non-structural carbohydrate reserves preceding dieback. Five- and six-year-old trees of U. minor (planted in the field with supplementary watering) belonging to clones of contrasted susceptibility to DED exhibited a different physiological response to inoculation with O. novo-ulmi. Stem hydraulic conductivity, leaf water potential and photosynthetic CO2 uptake decreased significantly relative to control trees inoculated with water only in DED susceptible clones. This is consistent with the “more defensive” chemical profile observed in resistant clones, i.e. with higher levels of saturated hydrocarbons (suberin and fatty acids) and phenolic compounds than in susceptible clones. These compounds could restrict the spread of O. novo-ulmi and contribute to preserving the near-normal physiological function of resistant trees when exposed to the pathogen. These results evidence common physiological responses of U. minor to flooding, drought and pathogen infection leading to xylem water disruption, leaf water stress and reduced net carbon gain. Still, seedlings of U. minor develop various mechanisms of acclimation to abiotic stresses that can play a role in surviving moderate periods of flood and drought. The chemical profile appears to be an important factor for the resistance of some genotypes of U. minor to DED. How abiotic stresses such as flooding and drought affect the capacity of resistant U. minor clones to face O. novo-ulmi is a key question that must be contemplated in future research.

De la isla de Menorca a las costas sur y este de Inglaterra: análisis del prototipo de torre Martello = From the island of Minorca to the south and east coasts of England: analysis of the prototype of the Martello tower

Esta tesis doctoral desarrolla una investigación original sobre las torres defensivas de Menorca y las torres Martello de las costas sur y este de Inglaterra. Con respecto a las torres menorquinas, se distinguen las de Alcaufar y Punta Prima, construidas por ingenieros militares españoles, en 1786; de las levantadas por el ejército británico durante su último periodo de dominación de la isla, entre 1798 y 1802. Estos ingenieros reales británicos construyen las torres Martello en las costas inglesas, entre 1805 y 1812; y otras, semejantes a ellas, en el resto de su Imperio, hasta mediados del siglo XIX. La falta de estudios que relacionen las torres defensivas de Menorca y las Martello inglesas dentro del marco disciplinario de la construcción, ha constituido la justificación de esta investigación. La hipótesis de trabajo plantea un objetivo principal: el estudio y análisis comparativo entre ellas, que se desarrolla en varios niveles de análisis: morfológico, físico-constructivo, de visibilidades; pero también territorial, histórico y poliorcético. Esta tesis cuestiona, en consecuencia, la idea tradicionalmente aceptada de que las torres Martello tomaran la torre de Mortella, en Córcega, o cualquiera de las denominadas torres "preMartello", como referencia para crear su prototipo. La metodología empleada combina los trabajos de gabinete con una intensa labor de campo, en la que se documentaron cincuenta y siete torres, catorce en Menorca y cuarenta y tres en Inglaterra. Se han redactado sus correspondientes fichas de datos, que incluyen aspectos generales - morfológicos y constructivos -, así como documentación fotográfica. Se han elaborado los levantamientos morfológicos de siete de estas torres, aquellas que por sus particularidades constructivas, o bien representan un determinado tipo de torre, o bien se distinguen del resto. Del mismo modo, se han desarrollado los levantamientos físico-constructivos y la caracterización de materiales de las cuatro torres más relevantes para este estudio: las menorquinas Alcaufar y Punta Prima, y las torres 24 y C, que ejemplifican, respectivamente, las levantadas en las costas sur y este de Inglaterra. El sistemático método de trabajo llevado a cabo ha favorecido la investigación y ha ayudado a obtener conclusiones que verifican la hipótesis planteada en la tesis y cumplen los objetivos establecidos al comienzo de la misma. ABSTRACT This doctoral thesis develops an original research on the defensive towers of Minorca, and the Martello towers on the south and east coasts of England. Regarding the Minorcan towers, Alcaufar and Punta Prima, built by the Spanish military engineers in 1786, must be distinguished from those erected by the British Army during its last period of domination of the island between 1798 and 1802. These Royal Engineers build the Martello towers on the English coasts between 1805 and 1812; and others, similar to them, in the rest of their Empire until the middle of the 19th century. The lack of studies linking these Minorcan and English towers, within the disciplinary framework of construction, has been the justification for this research. The hypothesis poses a main goal: the study and comparative analysis of them, which takes place at several levels of analysis: morphological, constructive, of visibilities; but also territorial, historical and poliorcetic. Consequently, this thesis questions the traditionally accepted notion that the Martello towers took the Corsican Mortella Tower, or any of the so-called “preMartello” towers as a reference to create their prototype. The methodology combines the cabinet works with significant fieldwork, in which fifty seven towers were documented, fourteen in Minorca and forty three in England. The corresponding data sheets were drafted including general aspects - morphological and constructive-, and photographic documentation. Morphological survey plans were developed for seven of these towers due to their construction peculiarities, which either denote a specific type of tower or makes it stand out from the rest. Likewise, constructive survey plans and material characterisation sheets of the four more relevant towers in this study were developed: the Minorcan Alcaufar and Punta Prima, and towers 24 and C, both respectively exemplifying those built on the south and east coasts of England. The systematic method of work encouraged the research and helped to draw conclusions that both confirm the hypothesis raised in the thesis and meet the objectives established at the beginning of it.

El Prado, de territorio a escenario : la construcción del espacio en un lugar tangible y su significado

"Si el hombre es el cuidador de las palabras y sólo de ellas emerge el sentido de las cosas, la arquitectura tiene un cometido preciso: hacer de las condiciones ya dadas de cada lugar palabras que signifiquen las cualidades de la existencia, y que desvelen la riqueza y contenidos que en ellas se contienen potencialmente" Ignasi Solá Morales. Lugar: permanencia o producción, 1992. Esta tesis surge tanto del afán por comprender la identidad de uno de los espacios más representativos de mi ciudad, asumido familiarmente pero que plantea muchas dudas respecto a su caracterización, como de la preocupación personal respecto a la aparente hegemonía del modelo urbano de la "ciudad genérica", crudamente expuesto por Rem Koolhaas a finales del siglo XX, que pone en crisis la ciudad histórica. El territorio, espacio físico concreto, y la memoria asociada a este, obliterados, son considerados como punto de partida para confrontarlos con la proclamación del nuevo modelo de "ciudad genérica", de raíz eminentemente económica y tecnológica. La realidad tangible de un espacio, aparentemente forjado en base a los valores denostados por el nuevo modelo propuesto, se estudia desde las premisas opuestas. La idea del no-lugar, teorizado por Marc Augé y tomado como modelo por Koolhaas, supone éste emancipado tanto de las preexistencias históricas como de su ubicación física concreta, planteando un tipo de espacio de representación al margen del territorio y la memoria. Sin pretender adoptar una postura resistente u opuesta, sino antitética y complementaria, se toman aquí las premisas de Koolhaas para contrastarlas con una porción del territorio a medio camino entre la arquitectura y la ciudad, a fin de desarrollar una reflexión que sirva de complemento y contrapeso al paradigma espacial que la “ciudad genérica” implica y cuya inmediatez y supuesta anomia parecen anular cualquier intención interpretativa al neutralizar los centros históricos y proclamar el agotamiento de la historia. El planteamiento de una teoría dicotómica frente al espacio y las teorías arquitectónicas asociadas a este ya fue formulado por Colin Rowe y Fred Koetter a finales de los años setenta del siglo pasado. Se plantea aquí la idea de una “ciudad tangible” como opuesta a la idea de la "ciudad genérica" enunciada por Koolhaas. Tomando el territorio y la memoria como referencia principal en un lugar concreto y huyendo de la premisa de la inmediatez del instante y el "presente perpetuo" proclamado por Koolhaas, del que según él seríamos prisioneros, se establece una distancia respecto al objeto de análisis que desarrolla el estudio en la dirección opuesta al supuesto origen del mismo, planteando la posibilidad de reactivar una reflexión en torno al territorio y la memoria en el seno del proceso global de habitación para poner de manifiesto determinados mecanismos de configuración de un espacio de representación al margen de la urgencia del presente, reactivando la memoria y su relación con el territorio como punto de partida. Desde de la reconstrucción hipotética del territorio, partiendo de la propia presencia física del mismo, su orografía, la paleo-biología, las analogías etológicas, los restos arqueológicos, la antropología o la historia, se reivindica la reflexión arquitectónica como disciplina diversa y privilegiada en cuanto al análisis espacial, tratando de discernir el proceso mediante el cual el Prado pasó de territorio a escenario. La organización cronológica del estudio y la incorporación de muy diversas fuentes, en su mayoría directas, pretende poner de manifiesto la condición transitiva del espacio de representación y contrastar el pasado remoto del lugar y su construcción con el momento actual, inevitablemente encarnado por el punto de vista desde el cual se desarrolla la tesis. El Prado parece albergar, agazapado en su nombre, la raíz de un origen remoto y olvidado. Si como enunciaba Ignasi Solá-Morales la función de la arquitectura es hacer aflorar los significados inherentes al lugar, esta tesis se plantea como una recuperación de la idea del vínculo entre el territorio y la memoria como fuente fundamental en la definición de un espacio de representación específico. El escrutinio del pasado constituye un acto eminentemente contemporáneo, pues el punto de vista y la distancia, inevitablemente condicionados por el presente, determinan la mirada. El culto contemporáneo a la inmediatez y la proclamación de la superación de los procesos históricos han relegado el pasado, en cierto grado, a depósito de restos o referente a superar, obviando su ineluctable condición de origen o momento anterior condicionante. Partiendo de la reconstrucción del lugar sobre el cual se halla el Prado ubicado y reconsiderando, según las premisas desarrolladas por la moderna historiografía, fundamentalmente desarrolladas por la Escuela francesa de los Annales, la cotidianeidad y lo anónimo como fuente de la que dimanan muchos de los actuales significados de nuestros espacios de representación, tomando como punto de partida un lugar remoto y olvidado, se estudia como se fue consolidando el Prado hasta devenir un lugar insigne de referencia asociado a los poderes fácticos y el espacio áulico de la capital de las Españas en el siglo XVII. El proceso mediante el cual el Prado pasó de territorio a escenario implica la recuperación de la memoria de un espacio agropecuario anónimo y el análisis de cómo, poco a poco, se fue depositando sobre el mismo el acervo de los diversos pobladores de la región que con sus particularidades culturales y sociales fueron condicionando, en mayor o menor grado, un lugar cuyo origen se extiende retrospectivamente hasta hace más de dos mil años, cuando se considera que pudo darse la primera habitación a partir de la cual, de manera ininterrumpida, el Prado ha venido siendo parte de lo que devino, más tarde, Madrid. La llegada de nuevos agentes, vinculados con estructuras de poder y territoriales que trascendían la inmediatez del territorio sobre el que se comenzó a erigir dicho lugar, sirven para repasar los diferentes depósitos ideológicos y culturales que han ido conformando el mismo, reivindicando la diversidad y lo heterogéneo del espacio de representación frente a la idea homogeneizadora que el modelo genérico implica. La constitución del Prado como un espacio de referencia asociado al paganismo arcaico a partir de la praxis espacial cotidiana, su relación con las estructuras defensivas de Al-Andalus y la atalaya Omeya, la apropiación del los primitivos santuarios por parte la iglesia, su relación con un determinado tipo de espiritualidad y las órdenes religiosas más poderosas de la época, la preferencia de Carlos V por Madrid y sus vínculos con la cultura europea del momento, o la definitiva metamorfosis del lugar a partir del siglo XVI y el advenimiento de un nuevo paganismo emblemático y estetizado, culminan con el advenimiento de lo económico como representación del poder en el seno de la corte y la erección del Palacio del Buen Retiro como manifestación tangible de la definitiva exaltación del Prado a espacio de representación áulico. Decía T.S. Elliot que la pugna por el espacio de la memoria constituye el principal rasgo del clasicismo, y el Prado, ciertamente, participa de ese carácter al que está profundamente asociado en la conciencia espacial de los madrileños como lugar de referencia. Acaso la obliteración del territorio y la memoria, propuestas en la “ciudad genérica” también tengan algo que ver con ello. ABSTRACT "If man is the caretaker of words and only they provide the sense of things, the architecture has a precise mission: to make out from the given conditions of each place words that mean the qualities of existence, and which unveil the wealth and content they potentially contain " Ignasi Solá Morales. Place: permanence or production, 1992. This thesis arises from both the desire to understand the identity of one of the most representative spaces of my city, assumed in a familiar way but that raises many doubts about its characterization, and from a personal concern about the apparent hegemony of the urban model of the "generic city " so crudely exposed by Rem Koolhaas in the late twentieth century that puts a strain on the historic city. The obliteration of the territory, specific physical space, and its associated memory, are considered as a starting point to confront them with the proclamation of the new model of "generic city" raised from eminently economic and technological roots. The tangible reality of a space, apparently forged based on the values reviled by the proposed new model, is studied from opposite premises. The idea of non-place, theorized by Marc Augé and modeled by Koolhaas, implies the emancipation from both historical preexistences and physical location, posing a type of space representation outside the territory and memory. Without wishing to establish a confrontational or opposite position, but an antithetical and complementary stance, the premises of Koolhaas are here taken to contrast them with a portion of territory halfway between architecture and the city, to develop a study that will complement and counterbalance the spatial paradigm that the "generic city" means and whose alleged immediacy and anomie appear to nullify any interpretative intention by neutralizing the historic centers and proclaiming the exhaustion of history. The approach of a dichotomous theory versus space and architectural theories associated with this were already formulated by Colin Rowe and Fred Koetter during the late seventies of last century. The idea of a "tangible city" as opposed to the idea of the "generic city" enunciated by Koolhaas arises here. Taking the territory and memory as the main reference in a particular place and trying to avoid the premise of the immediacy of the moment and the "perpetual present" proclaimed by Koolhaas, of which he pleas we would be prisoners, a distance is established from the object of analysis developing the study in the opposite direction to the alleged origin of it, raising the possibility of reactivating a reflection on the territory and memory within the overall process of inhabiting to reveal certain representational space configuration mechanisms outside the urgency of the present, reviving the memory and its relationship with the territory as a starting point. From the hypothetical reconstruction of the territory, starting from its physical presence, geography, paleo-biology, ethological analogies, archaeological remains, anthropology or history, architecture is claimed as a diverse as privileged discipline for spatial analysis, trying to discern the process by which the Prado moved from territory to stage. The chronological organization of the study and incorporating a variety of sources, most direct, aims to highlight the transitive condition of representational space and contrast the remote past of the place and its construction with the current moment, inevitably played by the view point from which the thesis develops. The Prado seems to harbor, in its name, the root of a remote and forgotten origin. If, as Ignasi Sola-Morales said, the aim of architecture is to bring out the meanings inherent in the site, this thesis is presented as a recovery of the idea of the link between the territory and memory as a key source in defining a specific space of representation. The scrutiny of the past is an eminently contemporary act, for the view and distance inevitably conditioned by the present, determine the way we look. The contemporary cult of immediacy and the proclamation of overcoming historical processes have relegated the past, to some extent, to remains deposit or a reference to overcome, ignoring its ineluctable condition as origin or previous constraint. From rebuilding the site on which the Prado is located and reconsidering everyday life and the anonymous as a source of many arising current meanings of our space of representation, according to the premises developed by modern historiography mainly developed by the French school of Annales, trying to recover the remote and forgotten is attempted, the thesis studies how el Prado was consolidated to become the most significant place of Madrid, deeply associated with the power in the capital of Spain during the XVII century. The process by which the Prado evolved from territory to stage involves the recovery of the memory of an anonymous agricultural space and the analysis of how, little by little, the influence of the various inhabitants of the region with their own and how their cultural and social peculiarities was deposited through time on the common ground and how that determined, to a greater or lesser degree, a place whose origin retrospectively extends over more than two thousand years ago, when we can consider the first inhabiting from which, without interruption, the Prado has come to be part of what became, later, Madrid. The arrival of new players, linked to power structures and territorial issues which transcended the immediacy of the territory on which the place begun to be a characteristic space, serve to review the different ideological and cultural deposits that have shaped the place, claiming diversity and heterogeneous space of representation before the homogenizing idea which the generic model implies. The constitution of the Prado as a benchmark associated with the archaic paganism developed from the ancient everyday spatial praxis, its relationship with the defensive structures of Al-Andalus and the Umayyad watchtower, the appropriation of the early sanctuaries by the roman church, its relationship with a certain type of spirituality and the most powerful religious orders of the time, the preference of Carlos V towards Madrid and its links with the European culture of the moment and the final metamorphosis of the place during the sixteenth century, end at the moment on which the advent of the economic as a representation of power within the court and the erection of the Palacio del Buen Retiro, as a tangible manifestation of the ultimate exaltation of courtly Prado space representation, happened in the mid XVII century. T. S. Elliot said that the struggle for memory space is the main feature of classicism, and the Prado certainly shares part of that character deeply associated in the mental spatial structure of the locals as a landmark. Perhaps the obliteration of territory and memory proposed in the "generic city" might also have something to do with that.

La construcción del espacio litoral : el caso de la costa de Cartagena

El litoral ha constituido a lo largo de la historia una importante fuente de recursos económicos además de un punto estratégico para la defensa del territorio. El comercio, la pesca o la industria de la sal han propiciado la formación de poblaciones y ciudades al borde del mar. La costa funcionó como un ámbito defensivo, peligroso e insalubre durante siglos donde el mar modulaba el frente costero sin grandes interacciones con un entorno prácticamente deshabitado. A mediados del siglo XIX, las innovaciones técnicas y la pacificación definitiva del Mediterráneo permiten poner en valor sus características naturales y de oportunidad. Sin perder del todo su valor defensivo, el litoral resurge como recurso productivo y como lugar de ocio y disfrute de la población. El valor estratégico de la costa quedará también reflejado en el marco normativo. El derecho civil moderno recuperará el concepto de Dominio público Marítimo Terrestre a través de la Ley de Aguas de 1866 que regulará también los usos y las limitaciones en la propiedad privada litoral. Desde ese momento, las transformaciones económicas, sociales, jurídicas y ambientales van a provocar un cambio significativo en la relación entre la sociedad y la costa que dará paso a la construcción del espacio litoral que hemos heredado. Desde la triple perspectiva del litoral como sistema físico ambiental, sistema económico, productivo y cultural, y sistema administrativo y legal, el principal objetivo de la tesis será reconstruir el proceso de transformación del litoral consecuencia de la evolución en la forma de producción del espacio, de área defensiva a recurso productivo, y desde mediados del siglo XIX hasta principios del siglo XXI. Sin embargo, la construcción del litoral no ha sido homogénea ni constante a lo largo del tiempo. Ha estado sujeta a los distintos vaivenes económicos y sociales pero también a los cambios en el modelo territorial definido por el marco legal vigente, así como a los reajustes del propio sistema físico. Como instrumento sociopolítico, el marco legal regula las presiones del sistema económico sobre el medio, apostando por una visión frente a otra, y posibilitando el grado de transformación final. Así, el conocimiento sobre el territorio en el que se interviene y la definición del modelo de litoral por parte de los poderes públicos irán configurando el espacio físico, económico y social desarrollado en la costa. Para la reconstrucción del proceso de construcción del litoral, la tesis define cuatro fases diferentes y aplica las hipótesis y la metodología a la costa de Cartagena. Se presenta gráficamente la evolución en los tres sistemas en cada una de las fases, y se recompone el relato histórico a través de los hitos más relevantes para el proceso. En cada una de las fases, el nuevo modelo intentará dar respuesta a todo aquello que no funcionó o se quedó a medias en el periodo anterior. Las crisis económicas provocan la ralentización de la actividad productiva y, consecuentemente, de las transformaciones en el territorio. Servirán para establecer, en principio, un cambio de paradigma en la lectura y gestión del litoral que acabará traduciéndose en un nuevo texto legislativo en materia de costas (1969, 1988 y 2013). La reforma de la normativa responde a una nueva forma de entender, ordenar, gestionar e intervenir en el territorio, donde se modulan las pautas pero también la intensidad en la intervención. Pero nace condicionada por el litoral heredado: los derechos generados durante la vigencia del marco legal anterior; el modelo económico y sus presiones y expectativas sobre el litoral; y el medio físico en el que se acumulan los procesos de degradación no resueltos y los nuevos riesgos. Así, las conclusiones de la tesis ponen de manifiesto la necesidad de una visión compleja e integral sobre el litoral, en la que el urbanismo y la ordenación del territorio serán fundamentales para afrontar los nuevos retos en su construcción a futuro. ABSTRACT The littoral has been throughout history an important source of economic resources and a strategic point for the defense of territory. Trade, fishing or salt industry have led to the formation of towns and cities on the edge of the sea. The coast served as a defensive, dangerous and unhealthy place where the sea modulated for centuries the waterfront without major interactions with a virtually uninhabited environment. In the mid-nineteenth century, technical innovations and the final pacification of the Mediterranean allowed to value its natural features and opportunities. Without entirely losing its defensive value, the coast emerges as a productive resource and as a place of leisure and enjoyment of people. The strategic value of the coast will also be reflected in the legal framework. The concept of maritime-terrestrial public domain will be recovered by the modern civil law and the law of waters of 1866 governs the uses and limitations of private ownership of the coast. Since then, the economic, social, legal and environmental changes will to cause a significant change in the relationship between society and the coast that will give way to the construction of littoral space inherited. From the triple perspective of the littoral as a physical environmental system, an economic, productive and cultural system, and an administrative and legal system, the main objective of the thesis is to rebuild its process of transformation, as a result of the evolution in the way that space is produced, from defensive zone to productive resource, and from the middle of the nineteenth century until the beginning of the twenty-first century. However, the construction of the coast has not been uniform nor constant over time. It has been subject to different economic and social fluctuations and also to changes in the territorial model defined by the legal framework in force, as well as to readjustments of the physical system itself. As socio-political instrument, the legal framework regulates the pressure of the economic system on the environment, it bets on a vision over another and facilitates the final degree of transformation. Thus, the knowledge on the territory that is being intervened and the definition of the model of shoreline by public authorities will configure the physical, economic and social space developed on the coast. For the reconstruction of the littoral building process, the thesis defines four different phases and applies the hypothesis and methodology to the coast of Cartagena. It introduces graphically the evolution of the three systems in each of the phases and it recomposes the historical account through of the most important milestones for the process. In each phase, the new model will attempt to answer everything that did not work or was half in the previous period. Economic crises cause a slowdown in productive activity and, consequently, in the changes of territory. They serve to establish, in principle, a paradigm shift for reading and managing the littoral, eventually resulting in new legal texts on coasts matter (1969, 1988 and 2013). The reform of legislation responds to a new way for understanding, arranging, managing and intervening on the territory, where the guidelines and also the intervention intensity are modulated. But it is born conditioned by the inherited coast: the rights generated under previous legal framework; the economic model and its pressures and expectations on the littoral; and the physical environment which accumulates degradation processes unresolved and new risks. Thus, the thesis conclusions highlight the need for a complex and comprehensive view on the littoral, where urban planning and land-use planning will be key to meet the future challenges in its construction.

Sofrimento e Adaptação: Aspectos Sociais e Psico-afetivos de Pacientes com Doença Periodontal Crônica

OS OBJETIVOS DESTE ESTUDO FORAM: CARACTERIZAR A POPULAÇÃO DE PACIENTES DE UMA CLÍNICA-ESCOLA; INVESTIGAR OS ASPECTOS PSICO-AFETIVOS ASSOCIADOS ÀS DOENÇAS PERIODONTAIS DESSES PACIENTES, ALÉM DOS RECURSOS DEFENSIVOS UTILIZADOS POR ELES. MÉTODO: LEVANTOU-SE DADOS SÓCIO-DEMOGRÁFICOS, DE SAÚDE GERAL E PERIODONTAL DE 789 PACIENTES ATENDIDOS NUM DEPARTAMENTO DE PERIODONTIA DE UMA CLÍNICA-ESCOLA DE ODONTOLOGIA, DADOS ESTES QUE CONSTITUÍRAM A ETAPA QUANTITATIVA DO ESTUDO. ESSA CARACTERIZAÇÃO FOI FEITA ATRAVÉS DE PLANILHAS ESPECIALMENTE ELABORADAS PARA A PESQUISA. A PARTIR DESSAS PLANILHAS, FOI SELECIONADA UMA SUB-AMOSTRA DE 273 PACIENTES QUE APRESENTARAM QUEIXAS EM TRÊS OU MAIS SISTEMAS ORGÂNICOS, ALÉM DA QUEIXA PERIODONTAL, OS QUAIS FORAM DENOMINADOS DE PACIENTES POLI-QUEIXOSOS. UMA TERCEIRA SUB-AMOSTRA INTEGROU 59 PACIENTES POLI-QUEIXOSOS, DIAGNOSTICADOS COM DOENÇA LEVE A MODERADA OU LEVE A SEVERA. DESSES PACIENTES, TRÊS FORAM ENTREVISTADOS E INTEGRARAM A AMOSTRA DA ETAPA QUALITATIVA DA PESQUISA. OS RESULTADOS INDICARAM QUE ENTRE PACIENTES POLI-QUEIXOSOS NÃO FOI ENCONTRADA CORRELAÇÃO SIGNIFICATIVA ENTRE DOENÇA PERIODONTAL LEVE A MODERADA OU LEVE A SEVERA COM GÊNERO, IDADE, ESTADO CIVIL, GRAU DE INSTRUÇÃO OU ATIVIDADE LABORAL. TAMBÉM NÃO HOUVE RELAÇÃO SIGNIFICATIVA QUANTO À PRESENÇA DE TABAGISMO, BRUXISMO, ONICOFAGIA E XEROSTOMIA. VERIFICAMOS QUE A DOENÇA PERIODONTAL CRÔNICA TEM SUAS ORIGENS NAS RELAÇÕES OBJETAIS DA MAIS TENRA INFÂNCIA E QUE AS ANSIEDADES ESQUIZO-PARANÓIDES QUE CARACTERIZAM ESSAS PRIMEIRAS RELAÇÕES, CONTINUAM PERMEANDO AS RELAÇÕES DURANTE TODA A VIDA DAS PACIENTES. COMO OS RECURSOS DEFENSIVOS UTILIZADOS SÃO PSIQUICAMENTE POUCO EVOLUÍDOS, O EQUILÍBRIO, A HOMEOSTASE É ENCONTRADA NA DOENÇA. CONCLUÍMOS QUE A DINÂMICA INTRA-PSÍQUICA PODE ESTAR ASSOCIADA NÃO SÓ À DOENÇA PERIODONTAL, MAS TAMBÉM AO ESTADO DE SAÚDE GERAL DESSES PACIENTES.

Sofrimento e Adaptação: Aspectos Sociais e Psico-afetivos de Pacientes com Doença Periodontal Crônica

OS OBJETIVOS DESTE ESTUDO FORAM: CARACTERIZAR A POPULAÇÃO DE PACIENTES DE UMA CLÍNICA-ESCOLA; INVESTIGAR OS ASPECTOS PSICO-AFETIVOS ASSOCIADOS ÀS DOENÇAS PERIODONTAIS DESSES PACIENTES, ALÉM DOS RECURSOS DEFENSIVOS UTILIZADOS POR ELES. MÉTODO: LEVANTOU-SE DADOS SÓCIO-DEMOGRÁFICOS, DE SAÚDE GERAL E PERIODONTAL DE 789 PACIENTES ATENDIDOS NUM DEPARTAMENTO DE PERIODONTIA DE UMA CLÍNICA-ESCOLA DE ODONTOLOGIA, DADOS ESTES QUE CONSTITUÍRAM A ETAPA QUANTITATIVA DO ESTUDO. ESSA CARACTERIZAÇÃO FOI FEITA ATRAVÉS DE PLANILHAS ESPECIALMENTE ELABORADAS PARA A PESQUISA. A PARTIR DESSAS PLANILHAS, FOI SELECIONADA UMA SUB-AMOSTRA DE 273 PACIENTES QUE APRESENTARAM QUEIXAS EM TRÊS OU MAIS SISTEMAS ORGÂNICOS, ALÉM DA QUEIXA PERIODONTAL, OS QUAIS FORAM DENOMINADOS DE PACIENTES POLI-QUEIXOSOS. UMA TERCEIRA SUB-AMOSTRA INTEGROU 59 PACIENTES POLI-QUEIXOSOS, DIAGNOSTICADOS COM DOENÇA LEVE A MODERADA OU LEVE A SEVERA. DESSES PACIENTES, TRÊS FORAM ENTREVISTADOS E INTEGRARAM A AMOSTRA DA ETAPA QUALITATIVA DA PESQUISA. OS RESULTADOS INDICARAM QUE ENTRE PACIENTES POLI-QUEIXOSOS NÃO FOI ENCONTRADA CORRELAÇÃO SIGNIFICATIVA ENTRE DOENÇA PERIODONTAL LEVE A MODERADA OU LEVE A SEVERA COM GÊNERO, IDADE, ESTADO CIVIL, GRAU DE INSTRUÇÃO OU ATIVIDADE LABORAL. TAMBÉM NÃO HOUVE RELAÇÃO SIGNIFICATIVA QUANTO À PRESENÇA DE TABAGISMO, BRUXISMO, ONICOFAGIA E XEROSTOMIA. VERIFICAMOS QUE A DOENÇA PERIODONTAL CRÔNICA TEM SUAS ORIGENS NAS RELAÇÕES OBJETAIS DA MAIS TENRA INFÂNCIA E QUE AS ANSIEDADES ESQUIZO-PARANÓIDES QUE CARACTERIZAM ESSAS PRIMEIRAS RELAÇÕES, CONTINUAM PERMEANDO AS RELAÇÕES DURANTE TODA A VIDA DAS PACIENTES. COMO OS RECURSOS DEFENSIVOS UTILIZADOS SÃO PSIQUICAMENTE POUCO EVOLUÍDOS, O EQUILÍBRIO, A HOMEOSTASE É ENCONTRADA NA DOENÇA. CONCLUÍMOS QUE A DINÂMICA INTRA-PSÍQUICA PODE ESTAR ASSOCIADA NÃO SÓ À DOENÇA PERIODONTAL, MAS TAMBÉM AO ESTADO DE SAÚDE GERAL DESSES PACIENTES.

Dinor-oxo-phytodienoic acid: A new hexadecanoid signal in the jasmonate family

Jasmonic acid and its precursors are potent regulatory molecules in plants. We devised a method for the simultaneous extraction of these compounds from plant leaves to quantitate changes in the levels of jasmonate family members during health and on wounding. During our study, we identified a novel 16-carbon cyclopentenoic acid in leaf extracts from Arabidopsis and potato. The new compound, a member of the jasmonate family of signals, was named dinor-oxo-phytodienoic acid. Dinor-oxo-phytodienoic acid was not detected in the Arabidopsis mutant fad5, which is incapable of synthesizing 7Z,10Z,13Z-hexadecatrienoic acid (16:3), suggesting that the metabolite is derived directly from plastid 16:3 rather than by β-oxidation of the 18-carbon 12-oxo-phytodienoic acid. Simultaneous quantitation of jasmonate family members in healthy leaves of Arabidopsis and potato suggest that different plant species have different relative levels of jasmonic acid, oxo-phytodienoic acid, and dinor-oxo-phytodienoic acid. We term these profiles “oxylipin signatures.” Dinor-oxo-phytodienoic acid levels increased dramatically in Arabidopsis and potato leaves on wounding, suggesting roles in wound signaling. Treatment of Arabidopsis with micromolar levels of dinor-oxo-phytodienoic acid increased the ability of leaf extracts to transform linoleic acid into the α-ketol 13-hydroxy-12-oxo-9(Z) octadecenoic acid indicating that the compound can regulate part of its own biosynthetic pathway. Tightly regulated changes in the relative levels of biologically active jasmonates may permit sensitive control over metabolic, developmental, and defensive processes in plants.

Female choice increases offspring fitness in an arctiid moth (Utetheisa ornatrix)

In Utetheisa ornatrix (Lepidoptera, Arctiidae), the female mates preferentially with larger males. Having a larger father results in the eggs being more richly endowed with defensive pyrrolizidine alkaloid (which the female receives from the male with the sperm package, in quantity proportional to the male's body mass, and passes on to the eggs); having a larger father also results in the sons and daughters themselves being larger (body mass is heritable in Utetheisa). We provide evidence herein that these consequences enhance the fitness of the offspring. Eggs sired by larger males are less vulnerable to predation (presumably because of their higher alkaloid content), whereas sons and daughters, by virtue of being larger, are, respectively, more successful in courtship and more fecund. The female Utetheisa, therefore, by being choosy, reaps both direct phenotypic and indirect genetic benefits.

Polyazamacrolides from ladybird beetles: Ring-size selective oligomerization

The pupal defensive secretion of the 24-pointed ladybird beetle, Subcoccinella vigintiquatuorpunctata, consists of a mixture of macrocyclic polyamines, dominated by the three dimeric, 30-membered macrocycles 11-13, derived from the two building blocks 11-(2-hydoxyethylamino)-5-tetradecenoic acid (9) and 11-(2-hydoxyethylamino)-5,8-tetradecadienoic acid (10). Smaller amounts of the four possible cyclic trimers of 9 and 10 were also detected, corresponding to 45-membered macrocycles. Structural assignments were based on NMR-spectroscopic investigations and HPLC–MS analyses. In addition, the all-S absolute configuration of the S. vigintiquatuorpunctata macrocycles was determined by comparison of derivatives of the natural material with enantiomerically pure synthetic samples. Comparing this alkaloid mixture with that of the pupal defensive secretion in related ladybird beetle species indicates that the degree of oligomerization of the 2-hydroxyethylamino carboxylic acid building blocks can be carefully controlled by the insects.

Chemical phenotype matching between a plant and its insect herbivore

Two potential outcomes of a coevolutionary interaction are an escalating arms race and stable cycling. The general expectation has been that arms races predominate in cases of polygenic inheritance of resistance traits and permanent cycling predominates in cases in which resistance is controlled by major genes. In the interaction between Depressaria pastinacella, the parsnip webworm, and Pastinaca sativa, the wild parsnip, traits for plant resistance to insect herbivory (production of defensive furanocoumarins) as well as traits for herbivore “virulence” (ability to metabolize furanocoumarins) are characterized by continuous heritable variation. Furanocoumarin production in plants and rates of metabolism in insects were compared among four midwestern populations; these traits then were classified into four clusters describing multitrait phenotypes occurring in all or most of the populations. When the frequency of plant phenotypes belonging to each of the clusters is compared with the frequency of the insect phenotypes in each of the clusters across populations, a remarkable degree of frequency matching is revealed in three of the populations. That frequencies of phenotypes vary among populations is consistent with the fact that spatial variation occurs in the temporal cycling of phenotypes; such processes contribute in generating a geographic mosaic in this coevolutionary interaction on the landscape scale. Comparisons of contemporary plant phenotype distributions with phenotypes of herbarium specimens collected 9–125 years ago from across a similar latitudinal gradient, however, suggest that for at least one resistance trait—sphondin concentration—interactions with webworms have led to escalatory change.

Correlated effects of sperm competition and postmating female mortality

Adaptations in one sex may impair fitness in the opposite sex. Experiments with Drosophila melanogaster have shown that seminal fluid from the male accessory gland triggers a series of postmating responses in the female, including increased egg laying rate and lower remating propensity, but that accessory gland proteins also increase female death rate. Here, we tested the relationships among the longevity of females mated to males from 51 chromosome-extracted D. melanogaster lines, male-mating ability, and sperm-competitive ability. We found significant differences in longevity of females mated to males of different genotypes, and all mated females showed a higher death rate than control virgin females shortly after mating. Both the age-independent mortality parameter (the intercept of the female's survival function) and the slope of the mortality rate curve were significantly correlated with the proportion of progeny sired by the first male to mate relative to tester males (sperm-defense ability, P1). No significant correlation was found between the proportion of progeny sired by the second-mating male relative to tester males (sperm-offense ability, P2) and any mortality parameter. Our results support the hypothesis of a tradeoff between defensive sperm-competitive ability of males and life-history parameters of mated females.

Manipulation of the phenolic chemistry of willows by gall-inducing sawflies

The ability to induce galls on plants has evolved independently in many insect orders, but the adaptive significance and evolutionary consequences of gall induction are still largely unknown. We studied these questions by analyzing the concentrations of various plant defense compounds in willow leaves and sawfly galls. We found that the galls are probably nutritionally beneficial for the sawfly larvae, because the concentrations of most defensive phenolics are substantially lower in gall interiors than in leaves. More importantly, changes in chemistry occur in a similar coordinated pattern in all studied willow species, which suggests that the insects control the phenolic biosynthesis in their hosts. The resulting convergence of the chemical properties of the galls both within and between host species indicates that the role of plant chemistry in the evolution of host shifts may be fundamentally less significant in gallers than in other phytophagous insects.

Establishment of an animal–bacterial association: Recruiting symbiotic vibrios from the environment

While most animal–bacterial symbioses are reestablished each successive generation, the mechanisms by which the host and its potential microbial partners ensure tissue colonization remain largely undescribed. We used the model association between the squid Euprymna scolopes and Vibrio fischeri to examine this process. This light organ symbiosis is initiated when V. fischeri cells present in the surrounding seawater enter pores on the surface of the nascent organ and colonize deep epithelia-lined crypts. We discovered that when newly hatched squid were experimentally exposed to natural seawater, the animals responded by secreting a viscous material from the pores of the organ. Animals maintained in filtered seawater produced no secretions unless Gram-negative bacteria, either living or dead, were reintroduced. The viscous material bound only lectins that are specific for either N-acetylneuraminic acid or N-acetylgalactosamine, suggesting that it was composed of a mucus-containing matrix. Complex ciliated fields on the surface of the organ produced water currents that focused the matrix into a mass that was tethered to, and suspended above, the light organ pores. When V. fischeri cells were introduced into the seawater surrounding the squid, the bacteria were drawn into its fluid-filled body cavity during ventilation and were captured in the matrix. After residing as an aggregate for several hours, the symbionts migrated into the pores and colonized the crypt epithelia. This mode of infection may be an example of a widespread strategy by which aquatic hosts increase the likelihood of successful colonization by rarely encountered symbionts.