Mapping and Introgression of QTL Involved in Fruit Shape Transgressive Segregation into 'Piel de Sapo' Melon (Cucumis melo L.)

A mapping F2 population from the cross ‘Piel de Sapo’ × PI124112 was selectively genotyped to study the genetic control of morphological fruit traits by QTL (Quantitative Trait Loci) analysis. Ten QTL were identified, five for FL (Fruit Length), two for FD (Fruit Diameter) and three for FS (Fruit Shape). At least one robust QTL per character was found, flqs8.1 (LOD = 16.85, R2 = 34%), fdqs12.1 (LOD = 3.47, R2 = 11%) and fsqs8.1 (LOD = 14.85, R2 = 41%). flqs2.1 and fsqs2.1 cosegregate with gene a (andromonoecious), responsible for flower sex determination and with pleiotropic effects on FS. They display a positive additive effect (a) value, so the PI124112 allele causes an increase in FL and FS, producing more elongated fruits. Conversely, the negative a value for flqs8.1 and fsqs8.1 indicates a decrease in FL and FS, what results in rounder fruits, even if PI124112 produces very elongated melons. This is explained by a significant epistatic interaction between fsqs2.1 and fsqs8.1, where the effects of the alleles at locus a are attenuated by the additive PI124112 allele at fsqs8.1. Roundest fruits are produced by homozygous for PI124112 at fsqs8.1 that do not carry any dominant A allele at locus a (PiPiaa). A significant interaction between fsqs8.1 and fsqs12.1 was also detected, with the alleles at fsqs12.1 producing more elongated fruits. fsqs8.1 seems to be allelic to QTL discovered in other populations where the exotic alleles produce elongated fruits. This model has been validated in assays with backcross lines along 3 years and ultimately obtaining a fsqs8.1-NIL (Near Isogenic Line) in ‘Piel de Sapo’ background which yields round melons.

Spawning and habitat management in salmonid populations at the southern edge of their natural ranges = Reproducción y gestión del hábitat en poblaciones de salmónidos en el extremo meridional de sus distribuciones naturales

Las poblaciones de salmónidos en la Península Ibérica (trucha común, Salmo trutta; y salmón atlántico, Salmo salar) se encuentran cerca del límite meridional de sus distribuciones naturales, y por tanto tienen una gran importancia para la conservación de estas especies. En la presente Tesis se han investigado algunos aspectos de la reproducción y de la gestión del hábitat, con el objeto de mejorar el conocimiento acerca de estas poblaciones meridionales de salmónidos. Se ha estudiado la reproducción de la trucha común en el río Castril (Andalucía, sur de España), donde se ha observado que la freza ocurre desde diciembre hasta abril con el máximo de actividad en febrero. Este hecho representa uno de los periodos reproductivos más tardíos y con mayor duración de toda la distribución natural de la especie. Además, actualmente se sabe que el resto de poblaciones andaluzas tienen periodos de reproducción similares (retrasados y extendidos). Análisis en la escala de la distribución natural de la trucha común, han mostrado que la latitud explica parcialmente tanto la fecha media de reproducción (R2 = 62.8%) como la duración del periodo de freza (R2 = 24.4%) mediante relaciones negativas: a menor latitud, la freza ocurre más tarde y durante más tiempo. Es verosímil que un periodo de freza largo suponga una ventaja para la supervivencia de las poblaciones de trucha en hábitats impredecibles, y por tanto se ha propuesto la siguiente hipótesis, que deberá ser comprobada en el futuro: la duración de la freza es mayor en hábitats impredecibles que en aquellos más predecibles. La elevada tasa de solapamiento de frezaderos observada en el río Castril no se explica únicamente por una excesiva densidad de reproductores. Las hembras de trucha eligieron lugares específicos para construir sus frezaderos en vez de dispersarse aleatoriamente dentro del hábitat adecuado para la freza que tenían disponible. Estas observaciones sugieren que las hembras tienen algún tipo de preferencia por solapar sus frezaderos. Además, en ríos calizos como el Castril, las gravas pueden ser muy cohesivas y difíciles de excavar, por lo que el solapamiento de frezaderos puede suponer una ventaja para la hembra, porque la excavación en sustratos que han sido previamente removidos por frezas anteriores requerirá menos gasto de energía que en sustratos con gravas cohesivas que no han sido alteradas. Por tanto, se ha propuesto la siguiente hipótesis, que deberá ser comprobada en el futuro: las hembras tienen una mayor preferencia por solapar sus frezaderos en ríos con sustratos cohesivos que en ríos con sustratos de gravas sueltas. En el marco de la gestión del hábitat, se han empleado dos enfoques diferentes para la evaluación del hábitat físico, con el objeto de cuantificar los cambios potenciales en la disponibilidad de hábitat, antes de la implementación real de determinadas medidas sobre el hábitat. En primer lugar, se ha evaluado el hábitat físico del salmón atlántico en el río Pas (Cantabria, norte de España), en la escala del microhábitat, empleando la metodología IFIM junto con un modelo hidráulico bidimensional (River2D). Se han simulado una serie de acciones de mejora del hábitat y se han cuantificado los cambios en el hábitat bajo estas acciones. Los resultados mostraron un aumento muy pequeño en la disponibilidad de hábitat, por lo que no sería efectivo implementar estas acciones en este tramo fluvial. En segundo lugar, se ha evaluado el hábitat físico de la trucha común en el río Tajuña (Guadalajara, centro de España), en la escala del mesohábitat, empleando la metodología MesoHABSIM. Actualmente, el río Tajuña está alterado por los usos agrícolas de sus riberas, y por tanto se ha diseñado una restauración para mitigar estos impactos y para llevar al río a un estado más natural. Se ha cuantificado la disponibilidad de hábitat tras la restauración planteada, y los resultados han permitido identificar los tramos en los que la restauración resultaría más eficaz. ABSTRACT Salmonid populations in the Iberian Peninsula (brown trout, Salmo trutta; and Atlantic salmon, Salmo salar) are close to the southern limit of their natural ranges, and therefore they are of great importance for the conservation of the species. In the present dissertation, some aspects of spawning and habitat management have been investigated, in order to improve the knowledge on these southern salmonid populations. Brown trout spawning have been studied in the river Castril (Andalusia, southern Spain), and it has been observed that spawning occurs from December until April with the maximum activity in February. This finding represents one of the most belated and protracted spawning periods within the natural range of the species. Furthermore, it is now known that the rest of Andalusian populations show similar (belated and extended) spawning periods. Broad-scale analyses throughout the brown trout natural range showed that latitude partly explained both spawning mean time (R2 = 62.8%) and spawning duration (R2 = 24.4%) by negative relationships: the lower the latitude, the later the spawning time and the longer the spawning period. It is plausible that a long spawning period would be an advantage for survival of trout populations in unpredictable habitats, and thus the following hypothesis has been proposed, which is yet to be tested: spawning duration is longer in unpredictable than in predictable habitats. High rate of redd superimposition observed in the river Castril was not only caused by high density of spawners. Trout females chose specific sites for redd construction instead of randomly dispersing over the suitable spawning habitat. These observations suggest that female spawners have some kind of preference for superimposing redds. Moreover, in limestone streams such as Castril, unused gravels can be very cohesive and hard to dig, and thus redd superimposition may be an advantage for female, because digging may require less energy expenditure in already used redd sites than in cohesive and embedded unused sites. Hence, the following hypothesis has been proposed, which is yet to be tested: females have a higher preference for superimposing redds in streambeds with cohesive and embedded substrates than in rivers with loose gravels. Within the topic of habitat management, two different approaches have been used for physical habitat assessment, in order to quantify the potential change in habitat availability, prior to the actual implementation of proposed habitat measures. Firstly, physical habitat for Atlantic salmon in the river Pas (Cantabria, northern Spain) has been assessed at the microhabitat scale, using the IFIM approach along with a two dimensional hydraulic model (River2D). Proposed habitat enhancement actions have been simulated and potential habitat change has been quantified. Results showed a very small increasing in habitat availability and therefore it is not worth to implement these measures in this stream reach. Secondly, physical habitat for brown trout in the river Tajuña (Guadalajara, central Spain) has been assessed at the mesohabitat scale, using the MesoHABSIM approach. The river Tajuña is currently impacted by surrounding agricultural uses, and thus restoration was designed to mitigate these impacts and to drive the river to a more natural state. Habitat availability after the planned restoration has been quantified, and the results have permitted to identify in which sites the restoration will be more effective.

Loss of social behaviors by Myxococcus xanthus during evolution in an unstructured habitat

Social behaviors are often targets of natural selection among higher organisms, but quantifying the effects of such selection is difficult. We have used the bacterium Myxococcus xanthus as a model system for studying the evolution of social interactions. Changes in the social behaviors of 12 M. xanthus populations were quantified after 1,000 generations of evolution in a liquid habitat, in which interactions among individuals were continually hindered by shaking and low cell densities. Derived lineages were compared with their ancestors with respect to maximum growth rate, motility rates on hard and soft agar, fruiting body formation ability, and sporulation frequency during starvation. Improved performance in the liquid selective regime among evolved lines was usually associated with significant reductions in all of the major social behaviors of M. xanthus. Maintenance of functional social behaviors is apparently detrimental to fitness under asocial growth conditions.

A novel microbial habitat in the mid-ocean ridge subseafloor

The subseafloor at the mid-ocean ridge is predicted to be an excellent microbial habitat, because there is abundant space, fluid flow, and geochemical energy in the porous, hydrothermally influenced oceanic crust. These characteristics also make it a good analog for potential subsurface extraterrestrial habitats. Subseafloor environments created by the mixing of hot hydrothermal fluids and seawater are predicted to be particularly energy-rich, and hyperthermophilic microorganisms that broadly reflect such predictions are ejected from these systems in low-temperature (≈15°C), basalt-hosted diffuse effluents. Seven hyperthermophilic heterotrophs isolated from low-temperature diffuse fluids exiting the basaltic crust in and near two hydrothermal vent fields on the Endeavour Segment, Juan de Fuca Ridge, were compared phylogenetically and physiologically to six similarly enriched hyperthermophiles from samples associated with seafloor metal sulfide structures. The 13 organisms fell into four distinct groups: one group of two organisms corresponding to the genus Pyrococcus and three groups corresponding to the genus Thermococcus. Of these three groups, one was composed solely of sulfide-derived organisms, and the other two related groups were composed of subseafloor organisms. There was no evidence of restricted exchange of organisms between sulfide and subseafloor habitats, and therefore this phylogenetic distinction indicates a selective force operating between the two habitats. Hypotheses regarding the habitat differences were generated through comparison of the physiology of the two groups of hyperthermophiles; some potential differences between these habitats include fluid flow stability, metal ion concentrations, and sources of complex organic matter.

Disrupting evolutionary processes: The effect of habitat fragmentation on collared lizards in the Missouri Ozarks

Humans affect biodiversity at the genetic, species, community, and ecosystem levels. This impact on genetic diversity is critical, because genetic diversity is the raw material of evolutionary change, including adaptation and speciation. Two forces affecting genetic variation are genetic drift (which decreases genetic variation within but increases genetic differentiation among local populations) and gene flow (which increases variation within but decreases differentiation among local populations). Humans activities often augment drift and diminish gene flow for many species, which reduces genetic variation in local populations and prevents the spread of adaptive complexes outside their population of origin, thereby disrupting adaptive processes both locally and globally within a species. These impacts are illustrated with collared lizards (Crotaphytus collaris) in the Missouri Ozarks. Forest fire suppression has reduced habitat and disrupted gene flow in this lizard, thereby altering the balance toward drift and away from gene flow. This balance can be restored by managed landscape burns. Some have argued that, although human-induced fragmentation disrupts adaptation, it will also ultimately produce new species through founder effects. However, population genetic theory and experiments predict that most fragmentation events caused by human activities will facilitate not speciation, but local extinction. Founder events have played an important role in the macroevolution of certain groups, but only when ecological opportunities are expanding rather than contracting. The general impact of human activities on genetic diversity disrupts or diminishes the capacity for adaptation, speciation, and macroevolutionary change. This impact will ultimately diminish biodiversity at all levels.

Habitat e genoma: possibili adattamenti di H. pylori allo stomaco umano

Helicobacter pylori è un batterio patogeno che infetta e abita lo stomaco umano. La sua diffusione è ubiquitaria nel mondo ed esso è responsabile di varie patologie, sia gastriche che extra-gastriche. Vista l’estrema ostilità del suo habitat, H. pylori necessita di specifici adattamenti che lo rendono unico nella sua capacità di tollerare l’estrema acidità dello stomaco umano, oltre ad evitare la risposta immunitaria dell’ospite. In questa tesi verranno adottati degli approcci bioinformatici per cercare di individuare quali possano essere gli adattamenti e le caratteristiche del genoma di questo batterio correlati con la sopravvivenza nell’ambiente gastrico e l’adattamento all’ospite umano.

The Rio Salado Riparian Habitat Restoration Area: Managing the Southwestern Willow Flycatcher

The following document identifies the impact to the current management plan of the Rio Salado Riparian Habitat Restoration Area in the event the endangered Southwestern Willow Flycatcher is found nesting at the project site. Rio Salado is managed by the City of Phoenix Parks and Recreation Department, and consists of a low-flow channel with native vegetation and wildlife along the Salt River. This paper analyzes the regulatory responsibilities of project site management and discusses the necessary adjustments to the management plan. Despite the current absence of the Southwestern Willow Flycatcher from Rio Salado, management should enter into a Safe Harbor Agreement with the U.S. Fish and Wildlife Service to legally protect themselves from the regulations stipulated in the Endangered Species Act.

Rural Development Trends and Land Use Policy in Colorado: Contributors to Habitat Fragmentation?

Fragmentation of wildlife habitat is a primary driver of global species decline. A major contributor to habitat fragmentation in the United States is rural residential development. Rural development in Colorado is occurring at rates far greater than the national average. Additionally, the lack of state-level planning control coupled with a lack of comprehensive, effective planning tools at the local level creates conditions that contribute to habitat fragmentation in many rural counties. Greater oversight and involvement in land use planning is needed by the state level to assist county governments. This study provides five recommendations to strengthen Colorado state land use policy in order to reduce habitat fragmentation.

Influence of habitat on nest location and reproductive output of Montagu’s Harriers breeding in natural vegetation

We examined distribution and breeding success of semi-colonial Montagu’s Harriers (Circus pygargus) in relation to habitat in Castellón province (eastern Spain). Breeding areas used by harriers at a 1-km2 scale were characterised by having intermediate percentages of scrub cover, their nesting habitat, and also had intermediate coverage of herbaceous crops and non-irrigated orchards. Out of all habitat variables considered, only the percentage of herbaceous crops within 500 m from individual nests had a positive and significant effect on breeding output of the species, suggesting that this habitat may be efficiently used by harriers to forage. Breeding output was also related to laying date and number of breeding neighbours within 500 m around nests, with pairs laying later and having a higher number of breeding neighbours showing lower fledged brood sizes. Number of neighbours (but not laying date) was positively related to scrub cover within 500 m and to cover of herbaceous crops within 2,000 m. Conservation actions for Montagu’s Harrier in the study area should be aimed at preserving areas of scrub with nearby presence of herbaceous crops or natural grasslands. However, habitat improvement for semi-colonial species such as Montagu’s Harrier may not result in a change of species distribution area, and good habitat areas may remain unoccupied, as social factors like presence of conspecifics play an important role in breeding area selection for these species.

X-Ray Imaging of SAPO-34 Molecular Sieves at the Nanoscale: Influence of Steaming on the Methanol-to-Hydrocarbons Reaction

The effect of a severe steaming treatment on the physicochemical properties and catalytic performance of H-SAPO-34 molecular sieves during the methanol-to-hydrocarbons (MTH) reaction has been investigated with a combination of scanning transmission X-ray microscopy (STXM), catalytic testing, and bulk characterization techniques, including ammonia temperature programmed desorption and 27Al and 29Si magic angle spinning nuclear magnetic resonance. For this purpose, two samples, namely a calcined and a steamed H-SAPO-34 catalyst powder, have been compared. It has been found that calcined H-SAPO-34 displays a high selectivity towards light olefins, yet shows a poor stability as compared to a zeolite H-ZSM-5 catalyst. Moreover, in situ STXM at the carbon K-edge during the MTH reaction allows construction of nanoscale chemical maps of the hydrocarbon species formed within the H-SAPO-34 aggregates as a function of reaction time and steam post-treatment. It was found that there is an initial preferential formation of coke precursor species within the core of the H-SAPO-34 aggregates. For longer times on stream the formation of the coke precursor species is extended to the outer regions, progressively filling the entire H-SAPO-34 catalyst particle. In contrast, the hydrothermally treated H-SAPO-34 showed similar reaction selectivity, but decreased activity and catalyst stability with respect to its calcined counterpart. These variations in MTH performance are related to a faster and more homogeneous formation of coke precursor species filling up the entire steamed H-SAPO-34 catalyst particle. Finally, the chemical imaging capabilities of the STXM method at the Al and Si K-edge are illustrated by visualizing the silicon islands at the nanoscale before and after steaming H-SAPO-34.

Total oxidation of naphthalene using palladium nanoparticles supported on BETA, ZSM-5, SAPO-5 and alumina powders

A range of catalysts based on Pd nanoparticles supported on inorganic supports such as BETA and ZSM-5 zeolites, a silicoaluminophosphate molecular sieve (SAPO-5) and γ-alumina as a standard support have been tested for the total oxidation of naphthalene (100 ppm, total flow 50 ml/min) showing a conversion to carbon dioxide of 100% between 165 and 180 °C for all the analysed catalysts. From the combined use of zeolites with PVP polymer protected Pd based nanoparticles, enhanced properties have been found for the total abatement of naphthalene in contrast with other kinds of catalysts. A Pd/BETA catalyst has been demonstrated to have excellent activity, with a high degree of stability, as shown by time on line experiments maintaining 100% conversion to CO2 during the 48 h tested.

Irrigation canals in a semi-arid agricultural landscape surrounded by wetlands: Their role as a habitat for birds during the breeding season

Traditional water supply systems in semi-arid agrarian ecosystems, mainly irrigation canals, contribute to the diversity of the landscape and influence the composition of species. To evaluate their effect on bird communities in the breeding season, we selected a rural area in southeastern Spain, where an intricate and extensive network of irrigation canals and cultivated areas is located between two wetlands declared as Natural Parks. Birds were counted at representative points distributed throughout the canal network at which we recorded several variables related to the physical features, the vertical and horizontal structure of associated vegetation, reed development (Phragmites australis) and land use in the neighboring areas. We detected 37 bird species, most of which were also breeding in the wetlands nearby. We used Hierarchical Partitioning analyses to identify the variables most strongly related to the probability of the presence of selected species and species richness. Vegetation cover and height close to the canals, together with reed development, were the most important types of variables explaining species presence and richness. We found that current management practices for reeds in canals are not well-suited for biodiversity conservation. We therefore propose alternatives that could be implemented in the area in cooperation with stakeholders.