Aortic disease in Marfan syndrome is caused by overactivation of sGC-PRKG signaling by NO

AbstractThoracic aortic aneurysm, as occurs in Marfan syndrome, is generally asymptomatic until dissection or rupture, requiring surgical intervention as the only available treatment. Here, we show that nitric oxide (NO) signaling dysregulates actin cytoskeleton dynamics in Marfan Syndrome smooth muscle cells and that NO-donors induce Marfan-like aortopathy in wild-type mice, indicating that a marked increase in NO suffices to induce aortopathy. Levels of nitrated proteins are higher in plasma from Marfan patients and mice and in aortic tissue from Marfan mice than in control samples, indicating elevated circulating and tissue NO. Soluble guanylate cyclase and cGMP-dependent protein kinase are both activated in Marfan patients and mice and in wild-type mice treated with NO-donors, as shown by increased plasma cGMP and pVASP-S239 staining in aortic tissue. Marfan aortopathy in mice is reverted by pharmacological inhibition of soluble guanylate cyclase and cGMP-dependent protein kinase and lentiviral-mediated Prkg1 silencing. These findings identify potential biomarkers for monitoring Marfan Syndrome in patients and urge evaluation of cGMP-dependent protein kinase and soluble guanylate cyclase as therapeutic targets.</jats:p

Reproductive assurance weakens pollinator-mediated selection on flower size in an annual mixed-mating species

Background and Aims In animal-pollinated plants, direct and indirect selection for large and small flowers in predominantly outcrossing and selfing species, respectively, is a common consequence of pollen limitation (PL). However, many hermaphroditic species show a mixed-mating system known as delayed selfing, which provides reproductive assurance (RA) only when outcrossing is not realized. Although RA is expected to reduce pollinator-mediated selection towards larger flowers, the consequences of delayed selfing for selection on flower size in mixed-mating species remain overlooked. We investigated whether RA weakens selection on flower size in Tuberaria guttata, a mixed-mating annual herb. Methods We related pollinator visitation rates to flower size and measured seed production in emasculated, hand cross-pollinated and intact (control) flowers in three natural populations. For each population, we estimated variation in PL and RA across individuals differing in flower size and phenotypic selection on this trait. Key Results Pollinator visitation increased and RA decreased with flower size in all populations. Increasing RA diminished but did not fully alleviate PL, because of early-acting inbreeding depression. In the least-visited and most pollen-limited population, RA increased seed production by >200 %, intensely counteracting the strong pollinator-mediated selection for larger corollas. In the most-visited population, however, RA increased seed production by an average of only 9 %. This population exhibited the largest fraction of individuals that showed a decrease in seed production due to selfing and the weakest pollinator-mediated selection on flower size. Conclusions The results suggest that the balance between the extent of RA and outcrossing contributes to determine flower size in mixed-mating systems. Pollinator-mediated selection favours larger flowers by increasing outcrossed seeds, but the benefits of RA greatly lessen this effect, especially under severe conditions of pollen limitation. Our findings also indicate that a mixed-mating system can represent an ‘evolutionary trap’ under an adequate pollinator supply.Fil: López Teixido, Alberto. Universidad Rey Juan Carlos; EspañaFil: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Flores grandes en un ambiente mediterráneo: costes y beneficios del despliegue floral en Cistaceae

Las plantas zoófilas (i.e. polinizadas por animales) abarcan una enorme diversidad de flores, que varían no sólo en la gama de colores, la forma y el diseño, si no también en el tamaño y el despliegue, la longevidad y el aroma floral. Históricamente, numerosos botánicos y biólogos evolutivos se han interesado en el estudio de los procesos que conducen a tal diversificación (Sprengel 1793; Darwin 1862, 1877; Stebbins 1950, 1970). En general, los científicos de ambas disciplinas acuerdan en conferir a los polinizadores un papel relevante en la evolución de la variabilidad floral observada en la naturaleza. Esta afirmación se apoya en el hecho de que las plantas zoófilas dependen de los polinizadores para reproducirse y son las flores las estructuras diseñadas para tal fin. Las flores juegan un papel crucial en la atracción a los polinizadores ofreciéndoles recompensas energéticas y nutritivas, mientras que éstos favorecen la reproducción transfiriendo el polen entre plantas dentro de las poblaciones. En conjunto, la diversidad taxonómica de polinizadores (insectos, reptiles, aves, mamíferos), que implica una gran diversidad morfológica, funcional y de comportamiento, se ajusta a la diversidad de las variantes florales (revisado en Fenster et al. 2004; ver también Aigner 2005; Smith et al. 2008). Por tanto, los polinizadores tienen un gran potencial de ejercer selección sobre los rasgos de las flores de aquellas plantas que visitan. El despliegue floral, determinado por el número y el tamaño de las flores, es un rasgo clave en la ecología reproductiva de las plantas polinizadas por animales. Este carácter está estrechamente ligado con la atracción de polinizadores, ya que mayores despliegues son detectados más fácilmente y ofrecen menores costes en los recorridos interflorales (Bell 1985; Harder y Barrett 1996; Ohashi y Yahara 2001). Además, las flores más grandes poseen un mayor contenido de recursos para los polinizadores, tales como polen y néctar (J Herrera 1992; Jones 2001; Arista y Ortiz 2007). El despliegue floral ha sido por tanto relacionado con incrementos en la diversidad (Andersson 1988; Aigner 2005), la frecuencia (Young y Stanton 1990; Medel et al. 2007), el número (Bell 1985; Johnson et al. 1995; Liao et al. 2009) y la duración de las visitas (Conner y Rush 1996; Thompson 2001; Nattero et al. 2011) en numerosas plantas polinizadas por insectos. Las plantas con mayor tamaño floral y en mayor número son visitadas como primera opción (Young y Stanton 1990; Brody y Mitchell 1997). Por tanto, el despliegue floral favorece la dispersión y deposición de polen incrementando así el éxito tanto masculino como femenino (Stanton et al. 1986; Kudoh y Whigham 1998; Harder y Johnson 2005). Como una consecuencia lógica de este hecho, muchos estudios han documentado selección fenotípica hacia mayor número o tamaño de las flores mediada por polinizador (Galen 1989; CM Herrera 1993; Conner y Rush 1997; Hodgins y Barrett 2008; Nattero et al. 2010a). En última instancia, para que pueda existir evolución, los procesos de diversificación en el despliegue floral deben estar acoplados a una variación genética a nivel intraindividual. En efecto, se sabe que entre poblaciones e incluso entre individuos dentro de poblaciones, existe una gran variabilidad en el tamaño floral con una heredabilidad significativa (Anderson y Widén 1993; Galen 1996; Ashman y Majestic 2006). Pero si los polinizadores ejercen presión selectiva contra flores pequeñas y el tamaño floral es heredable, entonces las flores deberían mostrar poca variación en este rasgo (ver Ushimaru et al. 2006).El proyecto REMEDINAL (S-0505/AMB/000355) de la Comunidad de Madrid, el proyecto CONSOLIDER MONTES (CSD2008-00040) del Ministerio de Ciencia e Innovación y el proyecto 014/2009 del Organismo Autónomo de Parques Nacionales subvencionaron la investigación de esta tesis. La Universidad Rey Juan Carlos me adjudicó un contrato PDI para su realización.Peer Reviewe

Sex-dependent selection on flower size in a large-flowered Mediterranean species: an experimental approach with Cistus ladanifer

Acknowledgments We are grateful to J.F. Scheepens and an anonymous reviewer for providing constructive comments to improve the manuscript. A. Greylak reviewed the English. We also thank Drs. J.C. Moreno and V. Mazimpaka for laboratory assistance. We are also grateful to C. García-Agulló for fieldwork support. M.B. held a collaboration grant at Autónoma University of Madrid, Spain.Larger flowers increase pollinator visit rates and reproductive success, so selection on flower size is usually mediated by pollinators. However, larger flowers involve costs imposed by resource limitation so environmental conditions may also modulate flower size. “Male function” hypothesis entails that the intensity of selection is sex-dependent, being greater through male fitness, whereas female fitness is more limited by resources. In this study we analyse pollinator-mediated phenotypic selection on flower size through both sexes in a large-flowered Mediterranean species, Cistus ladanifer. We experimentally manipulated flower size in two populations, measured its effect on male and female fitness and estimated the strength and direction of phenotypic selection through both sexes and populations. Unmanipulated control flowers received higher pollinator visit rates and dispersed a higher pollen amount than reduced flowers. This translated into selection towards larger flowers through male fitness in both populations. Nevertheless, flower size had little effect on female fitness. Fruit set was high but selection through this component of female function was not significant. Seed number increased in control flowers, especially in one population, where we detected positive selection on flower size. Our results suggest that pollinator-mediated phenotypic selection on flower size in this large-flowered Mediterranean species is especially modulated by male fitness, but flower size adjustment may also be a result of a simultaneous selection through both sexes that, in turn, is dependent of ecological context.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Disproportionate carbon and water maintenance costs of large corollas in hot Mediterranean ecosystems

Acknowledgments Two anonymous reviewers provided constructive comments to improve the manuscript. We thank to F. Castellanos, T.E. Gimeno, T. Izquierdo and A. Lázaro-Nogal for fieldwork support. T.E. Gimeno also provided constructive comments during sampling design. We are also grateful to A. Forner and D. López for logistic support. This study was supported by the REMEDINAL project (S-0505/AMB/000355) of Comunidad de Madrid, Spain, and by CONSOLIDER MONTES project (CSD2008-00040) of the Spanish Ministerio de Ciencia e Innovación. A.L.T. held a PDI fellowship at Rey Juan Carlos University, Spain.Larger corollas increase the reproductive success of entomophilous plants, but are also associated with increased carbon and water costs, especially under hot and dry conditions. Minimizing floral carbon and water loss by reducing corolla size should be potentially advantageous for plants living in these environments. We quantify maintenance costs of corollas (water and carbon) in large-flowered rockroses (Cistus spp.) in a Mediterranean ecosystem. We performed field studies of two coflowering sympatric Cistus of contrasting corolla size to analyze water costs. Additionally, we used the larger-flowered species (C. ladanifer) to analyze the effects of intraspecific variation in corolla size on floral net carbon exchange and transpiration rates. We also assessed the mean daily percentage of plant water and carbon consumed by corollas by comparing with that of leaves at the time of flowering in C. ladanifer. Temperature and corolla area increased water maintenance costs, following an allometric relationship where transpiration rate per unit of area increased with corolla area. Larger flowers tended to heat less under strong irradiance than smaller ones in both species, especially in C. ladanifer, demonstrating a stronger transpirational cooling effect on larger flowers. In terms of carbon, temperature significantly affected net carbon exchange rates, which were not affected by corolla size. Daily water and carbon expenses of corolla were ca. 50% of those of leaves on an organ surface area basis. Our results suggest that water and carbon maintenance costs of large flowers in the Mediterranean impose significant constraints to corolla size, ecophysiologically favoring smaller-flowered individuals in these ecosystems.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Large and abundant flowers increase indirect costs of corollas: a study of coflowering sympatric Mediterranean species of contrasting flower size

Acknowledgments A. Traveset and J. M. Iriondo provided constructive comments during earlier versions of the manuscript. We also thank to R. Aceves, E. Barahona, F. Castellanos, C. de Castro, J. Iglesias and H. Lantarón for fieldwork support. We are also grateful to Y. Valiñani and E. Galisteo for lab assistance and Lori J. De Hond for linguistic assistance. This study was supported by CONSOLIDER MONTES project (CSD2008-00040) of the Spanish Ministerio de Ciencia e Innovación. A.L.T. held a PDI fellowship at Rey Juan Carlos University, Spain. The experiments comply with the current laws of Spain.Large floral displays receive more pollinator visits but involve higher production and maintenance costs. This can result in indirect costs which may negatively affect functions like reproductive output. In this study, we explored the relationship between floral display and indirect costs in two pairs of coflowering sympatric Mediterranean Cistus of contrasting flower size. We hypothesized that: (1) corolla production entails direct costs in dry mass, N and P, (2) corollas entail significant indirect costs in terms of fruit set and seed production, (3) indirect costs increase with floral display, (4) indirect costs are greater in larger-flowered sympatric species, and (5) local climatic conditions influence indirect costs. We compared fruit set and seed production of petal-removed flowers and unmanipulated control flowers and evaluated the influence of mean flower number and mean flower size on relative fruit and seed gain of petal-removed and control flowers. Fruit set and seed production were significantly higher in petal-removed flowers in all the studied species. A positive relationship was found between relative fruit gain and mean individual flower size within species. In one pair of species, fruit gain was higher in the large-flowered species, as was the correlation between fruit gain and mean number of open flowers. In the other pair, the correlation between fruit gain and mean flower size was also higher in the large-flowered species. These results reveal that Mediterranean environments impose significant constraints on floral display, counteracting advantages of large flowers from the pollination point of view with increased indirect costs of such flowers.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Forest fragmentation and loss of threatened ferns habitat in Fragas do Eume Natural Park (NW Spain)

A pesar de la intensa destrucción sufrida por los bosques de las costas de Europa, hay pocos estudios sobre la fragmentación de estos ecosistemas y sus consecuencias sobre la biodiversidad. El P. N. Fragas do Eume es una de las mejores representaciones de los bosques del litoral atl ántico europeo y tiene importantes poblaciones de helechos ibero-macaronésicos amenazados en sus bosques de ribera. En este trabajo se estudió la distribución de las clases de ocupación del suelo de este parque a partir de imágenes aéreas de los años 2002 y 2003. El bosque en conjunto ocupa el 30% de la superficie y corresponde principalmente a tres parches de gran tamaño. No obstante, la mayoría de los parches son muy pequeños (<10 ha) y tienen escasa o nula superficie no afectada por los factores de borde. En las riberas, la deforestación es menor y el bosque cubre el 76% de la longitud de los cauces. Hay 47 km de bosque de ribera a baja altitud (<400 m) y orientado al N, hábitat óptimo de helechos amenazados. La restauración del bosque en las riberas degradadas debe ser una medida prioritaria para la recuperación de estos helechos.Despite large destruction suffered by the forests of coastal Europe, few studies have examined the fragmentation of these ecosystems and its consequences on biodiversity. Fragas do Eume Natural Park is one of the best remaining forests in the Atlantic coast of Europe and has important populations of threatened Ibero-Macaronesian ferns in its riparian forests. The distribution of land cover classes in this Park was studied by using aerial images from the years 2002 and 2003. The whole forest occupies 30% of the area and is mainly held by three big patches. Nevertheless, most patches are very small (<10 ha) and affected by edge factors. In riversides, deforestation was less intense and 76% of the stream length is covered by forest. North-facing low-altitude (<400 m) riparian forest, optimum habitat for threatened ferns, occupies 47 km of streams. Forest restoration in the damaged riversides must be a priority action to conserve these ferns.Contrato para asistencia técnica 215/2006 de la Consellería de Medio Ambiente e Desenvolvemento Sostible de Galicia

Temperature-Limited Floral Longevity in the Large-Flowered Mediterranean Shrub Cistus Ladanifer (Cistaceae)

We are grateful to two anonymous reviewers for providing helpful comments, and we thank PlantScribe (http://www .plantscribe.com) for editing a final version of the manuscript. We also thank C. Botejara and L. Zamorano for fieldwork support and A. Escudero, B. Martínez, M. Méndez, and S. G. Rabasa for statistical advice. C. Caruso, J. Herrera, and M. Méndez provided valuable comments in early versions of the manuscript. This study was supported by the REMEDINAL project (S-0505/AMB/000355) of Comunidad de Madrid, Spain, and by the CONSOLIDERMONTES project (CSD2008- 00040) of the Spanish Ministerio de Ciencia e Innovación.Premise of research. Larger and longer-lived flowers are more frequently pollinated, but they are associated with high maintenance costs due to greater water usage. The Mediterranean climate limits plant reproduction and maximizes resource use efficiency, so smaller and short-lived flowers are potentially advantageous under hot and dry conditions. Methodology. We experimentally evaluated the relationship between the floral longevity of Cistus ladanifer, a large-flowered Mediterranean shrub, and pollination, flower size, and temperature at two different altitudes with contrasting climatic conditions. We hypothesized that flower size and longevity would be reduced in the drier and hotter conditions of the lower-altitude site. In addition, we expected that floral longevity would decrease with experimental pollen deposition, flower size, and temperature. We pollinated and capped flowers to evaluate the variation in floral longevity by comparing actual and potential floral longevity at low and high altitudes. Pivotal results. In agreement with our hypothesis, flower size was observed to increase with altitude, but, contrary to expectations, floral longevity decreased at the high altitude since temperature increased during the flowering time. Floral longevity tended to be short but depended on pollination, such that potential floral longevity was greater than actual floral longevity. Capped flowers lasted longer (1.31 ± 0.65 d) than control (0.95 ± 0.39 d) or hand-pollinated (0.60 ± 0.08 d) flowers. At the high altitude, larger flowers and higher temperatures resulted in a reduction in both the observed and potential floral longevity, but temperature had a differential effect in limiting potential floral longevity. Conclusions. Our experimental survey reported short-lived flowers and limitations in floral longevity when flowers were larger and temperatures were higher. Overall, the results reveal an important effect of temperature on increasing floral maintenance costs, imposing selective pressures on flower size, and longevity in large-flowered Mediterranean plants.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Reproductive assurance weakens pollinator-mediated selection on flower size in an annual mixed-mating species

ACKNOWLEDGEMENTS We thank three anonymous reviewers and G. Gleiser, J.M. Iriondo and J. Ollerton for providing helpful comments. A.P. Paglia provided statistical advice. We are also grateful to Á. Teijido for fieldwork support.Background and Aims In animal-pollinated plants, direct and indirect selection for large and small flowers in predominantly outcrossing and selfing species, respectively, is a common consequence of pollen limitation (PL). However, many hermaphroditic species show a mixed-mating system known as delayed selfing, which provides reproductive assurance (RA) only when outcrossing is not realized. Although RA is expected to reduce pollinator-mediated selection towards larger flowers, the consequences of delayed selfing for selection on flower size in mixed-mating species remain overlooked. We investigated whether RA weakens selection on flower size in Tuberaria guttata, a mixed-mating annual herb. Methods We related pollinator visitation rates to flower size and measured seed production in emasculated, hand cross-pollinated and intact (control) flowers in three natural populations. For each population, we estimated variation in PL and RA across individuals differing in flower size and phenotypic selection on this trait. Key Results Pollinator visitation increased and RA decreased with flower size in all populations. Increasing RA diminished but did not fully alleviate PL, because of early-acting inbreeding depression. In the least-visited and most pollen-limited population, RA increased seed production by >200 %, intensely counteracting the strong pollinator-mediated selection for larger corollas. In the most-visited population, however, RA increased seed production by an average of only 9 %. This population exhibited the largest fraction of individuals that showed a decrease in seed production due to selfing and the weakest pollinator-mediated selection on flower size. Conclusions The results suggest that the balance between the extent of RA and outcrossing contributes to determine flower size in mixed-mating systems. Pollinator-mediated selection favours larger flowers by increasing outcrossed seeds, but the benefits of RA greatly lessen this effect, especially under severe conditions of pollen limitation. Our findings also indicate that a mixed-mating system can represent an ‘evolutionary trap’ under an adequate pollinator supply.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Flower size and longevity influence florivory in the large-flowered shrub Cistus ladanifer

Acknowledgements We are grateful to Jeff Ollerton for reviewing the English and two anonymous reviewers for providing comments. This study was supported by the REMEDINAL project (S-0505/AMB/000355) of Comunidad de Madrid, Spain, and by CONSOLIDER MONTES project (CSD2008-00040) of the Spanish Ministerio de Ciencia e Innovación. A.L.T. held a PDI fellowship at Rey Juan Carlos University, Spain.Plants with larger and longer-lived flowers receive more pollinator visits and increase reproductive success, though may also suffer more from antagonistic interactions with animals. Florivores can reduce fruit and seed production, so selection on flower size, floral longevity and/or number of flowers may thus be determined by the relative effects of both pollinators and florivores. In this study flowers of Cistus ladanifer, a large-flowered Mediterranean shrub, were monitored to evaluate the effects of flower size, floral longevity and number of flowers on levels of florivory in four populations. Number of flowers was variable but did not differ among populations. Both flower size and floral longevity of C. ladanifer showed broad variation and significantly differed among populations. Overall, 7% of flowers suffered attack by florivores, which were mainly ants picking the stamens and beetles consuming petals and pollen. Within-populations, larger and longer-lived flowers tended to be affected by florivores more frequently. The low overall incidence of florivores and its lack of between-population variation suggest that florivory may not influence intraspecific variation of these floral traits. However, moderate florivory levels on the largest and longest-lived flowers open the possibility of exerting selection towards smaller and shorter-lived flowers in some of the populations studied.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu