256 research outputs found
Proteomic profiling of Burkholderia cenocepacia clonal isolates with different virulence potential retrieved from a cystic fibrosis patient during chronic lung infection
Respiratory infections with Burkholderia cepacia complex (Bcc) bacteria in cystic fibrosis (CF) are associated with a worse prognosis and increased risk of death. In this work, we assessed the virulence potential of three B. cenocepacia clonal isolates obtained from a CF patient between the onset of infection (isolate IST439) and before death with cepacia syndrome 3.5 years later (isolate IST4113 followed by IST4134), based on their ability to invade epithelial cells and compromise epithelial monolayer integrity. The two clonal isolates retrieved during late-stage disease were significantly more virulent than IST439. Proteomic profiling by 2-D DIGE of the last isolate recovered before the patient's death, IST4134, and clonal isolate IST439, was performed and compared with a prior analysis of IST4113 vs. IST439. The cytoplasmic and membrane-associated enriched fractions were examined and 52 proteins were found to be similarly altered in the two last isolates compared with IST439. These proteins are involved in metabolic functions, nucleotide synthesis, translation and protein folding, cell envelope biogenesis and iron homeostasis. Results are suggestive of the important role played by metabolic reprogramming in the virulence potential and persistence of B. cenocepacia, in particular regarding bacterial adaptation to microaerophilic conditions. Also, the content of the virulence determinant AidA was higher in the last 2 isolates. Significant levels of siderophores were found to be secreted by the three clonal isolates in an iron-depleted environment, but the two late isolates were more tolerant to low iron concentrations than IST439, consistent with the relative abundance of proteins involved in iron uptake.This work was supported by FEDER and FCT – Fundação para a Ciência e a Tecnologia (contract PEst-OE/EQB/LA0023/2011_ research line: Systems and Synthetic Biology; PhD grant to A.M. – SFRH/BD/37012/2007, and PD grants to S.S. – SFRH/BPD/75483/2010 and C.C. – SFRH/BPD/ 81220/2011. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio
Assessing the ability of novel ecosystems to support animal wildlife through analysis of diurnal raptor territoriality
Novel ecosystems have emerged through human intervention and are rapidly expandingaround the world. Whether they can support animal wildlife has generated considerable controversy.Here we developed a new approach to evaluate the ability of a novel forest ecosystem,dominated by the exotic tree species Eucalyptus globulus, to support animal wildlife inthe medium and long term. To evaluate this ability, we took advantage of the fact that speciesterritory size decreases with increasing habitat quality, and we used territoriality of araptor guild composed of Northern Goshawk (Accipiter gentilis), Eurasian Sparrowhawk(A. nisus) and Common Buzzard (Buteo buteo) as indicator. We compared the territorialityof these species in the novel ecosystem with that in other ecosystems found in the literature.Average distances between con-specifics in the novel ecosystem were similar, or evenshorter, than those in other ecosystems. Average distances between Goshawk con-specificswere among the shortest described in the literature. All three species nested preferably
in mixed stands abundant in large exotic trees, with high structural complexity and abundance of native species within the stand. Key factors supporting this diverse and dense raptor community were the special forest management system implemented in the study area
and the agricultural matrix located close to forest plantations that complements the supply
of prey. Our results suggest that forest management that promotes a complex and suitable
forest structure can increase the ability of novel forest ecosystems to support wildlife biodiversity, particularly a diverse nesting community of forest-dwelling raptors and their preys.
The results further suggest the suitability of territoriality for assessing this potential of novel
ecosystemsMinisterio de Ciencia y TecnologíaUniversidad de AlcaláMinisterio de Educación y Cienci
Higher reproductive success of small males and greater recruitment of large females could explain the strong reversed sexual dimorphism (RSD) in the northern goshawk
Abstract Reversed sexual dimorphism (RSD), whichoccurs when the female of a species is larger than the male,is the rule for most birds of prey but the exception amongother bird and mammal species. The selective pressuresthat favour RSD are an intriguing issue in animal ecology.Despite the large number of hypotheses proposed to explainthe evolution of RSD, there is still no consensus about themechanisms involved and whether they act on one or bothsexes, mainly because few intrapopulation studies havebeen undertaken and few raptor species have been investigated.Using the strongly size-dimorphic northern goshawk(Accipiter gentilis L.) as a model, we studied a populationwith one of the highest densities of breeding pairs reportedin the literature in order to understand selective pressuresthat may favour RSD. We evaluated life-history processes,including recruitment of adult breeders and reproductivesuccess, and we explored the mechanisms thought to act oneach sex, including hunting efficiency, diet, body conditionand mate choice. We found that smaller males producedmore fledglings than larger ones, but there was no relationshipbetween size and reproductive success for femalesMinisterio de Educación y Cienci
Territoriality in diurnal raptors: relative roles of recent evolution, diet and nest site
Animal territoriality, defined here as defence of well-delimited breeding areas to exclude competitors, has beenwidely studied. However, the phylogenetic and ecological characteristics influencing the variation in the expressionof this behaviour are poorly understood. We evaluated the effect of phylogeny and key ecological factors on territorialbehaviour and territory size in diurnal raptors from the western Palearctic and New World. To our knowledge, ourwork is the first comparative analysis of raptor territorial behaviour and territory size that accounts for phylogeneticrelationships. One important finding is that territorial behaviour has not been strongly conserved across evolutionarytime, but differences in territoriality of diurnal raptors have been influenced by recent evolution, which has ledto variations of this behaviour in response to changes in climate and habitat. Raptor current ecology is also associatedwith the expression of these traits. Species that capture more agile prey and nest in more protected sites weremost likely to be territorial. Additionally, territorial species that are bigger and capture more agile and bigger preydefended larger territories than species feeding on more vulnerable and smaller prey. We discuss potential mechanismsfor these patterns and the implications of our findings for future research on avian territoriality.Comisión Interministerial de Ciencia y Tecnología-CICYTREMEDINALMinisterio de Educación y Cienci
Anything for a quiet life: shelter from mobbers drives reproductive success in a top-level avian predator
17 p.Understanding how habitat structure relates to reproductive performance of species can help identify what habitats are of the highest quality for a given species and thereby guide effective management. Here, we compared the influence of prey abundance and the amount of shelter area on the relationship between habitat and breeding performance. We focused on the forest-dwelling northern goshawk Accipiter gentilis in an agroforestry system. Using structural equation modelling, we tested the associations between reproductive performance and three explanatory factors: habitat structure, abundance of food resources or levels of mobbing disturbance, and prey supply to the nest. Our results suggest that habitat structure influences reproductive performance through shelter rather than through prey abundance. During the study period, forested habitats in the breeding territories provided shelter to the goshawk, reducing disturbance by carrion crows Corvus corone, which acted as large, aggressive, social mobbers. Decreased disturbance increased prey supply to the nest, probably because it favored food accessibility and male goshawk foraging efficiency. Habitat was not significantly associated with quality of the breeders, both in terms of body size and seniority in the territories. Our findings suggest that reproductive performance, and therefore habitat quality, may depend more on sheltered access to food resources than on the amount of food available. Our observation that mobbers decrease predator foraging efficiency highlights the possibility of designing effective, socially acceptable predator management strategies to protect sensitive domestic prey.Ministerio para la Transición Ecológica y el Reto DemográficoMinisterio de Educación y CienciaMinisterio de Ciencia e InnovaciónComunidad de MadridUniversidad de Alcal
Spatial relationships and mechanisms of coexistence between dominant and subordinate top predators
Most forest ecosystems contain a diverse community of top-level predators. How these predator species interact, and howtheir interactions infl uence their spatial distribution is still poorly understood.Here we studied interactions among top predators in a guild of diurnal forest raptors in order to test the hypothesisthat predation among competing predators (intraguild predation) signifi cantly aff ects the spatial distribution of predatorspecies, causing subordinate species to nest farther away from the dominant ones.Th e study analyzed a guild in southwestern Europe comprising three raptor species. For 8 years we studied the spatialdistribution of used nests, breeding phenology, intraguild predation, territory occupancy, and nest-builder species andsubsequent nest-user species.Th e subordinate species (sparrowhawk Accipiter nisus ) nested farther away from the dominant species (goshawk A. gentilis), which preyed on sparrowhawks but not on buzzards Buteo buteo , and closer to buzzards, with which sparrowhawks donot share many common prey. Th is presumably refl ects an eff ort to seek protection from goshawks. Th is potential positiveeff ect of buzzards on sparrowhawks may be reciprocal, because buzzards benefi t from old sparrowhawk nests, which buzzardsused as a base for their nests, and from used sparrowhawk nests, from which buzzards stole prey. Buzzards occasionallyoccupied old goshawk nests.Universidad de Alcalá de Henare
Prey preferences and recent changes in diet of a breeding population of the Northern Goshawk Accipiter gentilis in Southwestern Europe
Capsule: Northern Goshawk Accipiter gentilis diet has changed significantly since the 1980s,probably due to changes in populations of preferred prey species.Aims and methods: To assess changes to the breeding season diet of the Northern Goshawk insouthwest Europe over three decades. We examined prey remains at and around nests andassessed avian prey availability using point count surveys.Results: During 2008&#-11, Goshawks mainly ate birds, with Feral Pigeons Columba livia f. domesticabeing the most important prey species. Goshawks preferred prey of 100&;8722#400 g and forest preyspecies to non-forest species. Goshawk diet has changed significantly over recent decades: 22%of current prey items belong to species that were not part of the diet in the 1980s. We suggestthat these dietary changes reflect changes in the abundance of prey species of the preferredsize caused by changes in land use leading to an increase in forest cover, new prey speciescolonization and changes in the abundance and management of domestic prey.Conclusion: This study emphasizes that major transformations occurring in agroforestry systemsare affecting the main preferred prey of important forest predators, which may haveconsequences for conservation of both the predators and their prey
Breeding habitat preferences and reproductive success of Northern Goshawk (Accipiter gentilis) in exotic Eucalyptus plantations in southwestern Europe
With ongoing degradation of natural forests and spread of forest plantations, plantations must play an increasinglyimportant role in biodiversity conservation. Study of habitat selection and reproductive success ofsurrogate species in plantations can guide forest management decisions for increasing biodiversity. In this paperwe studied the suitability of exotic Eucalyptus plantations managed at low intensity in northwestern Spain asbreeding habitat for Northern Goshawk (Accipiter gentilis), a top predator frequently considered a surrogatespecies in conservation.Goshawks showed high breeding density, high reproductive success and a regular spatial distribution ofnesting territories. Territoriality was the most important determinant of habitat selection. Goshawks selectedextra-mature Eucalyptus trees in areas of high structural complexity (high tree density, tree species richness, andnumber of tree strata) in the most heterogeneous forest stands (old-mixed Eucalyptus). Reproductive successdecreased with increasing local density of breeding pairs, but reproductive success was not related to structuralcharacteristics of nest stands.The studied plantations provided a suitable breeding habitat for Goshawks. The birds preferred to nest inlarge Eucalyptus trees with appropriate structure in their immediate surroundings. The strong preference ofGoshawks for structurally mature forest patches may make them useful as a surrogate species for assessing theability of forest management practices to promote overall biodiversity in exotic Eucalyptus plantations exploited at low intensity.Comisión Interministerial de Ciencia y Tecnología-CICYTMinisterio de Educación y CienciaMinisterio de Economía y CompetitividadREMEDINALUniversidad de Alcal
MVA-based vaccine candidates encoding the native or prefusion-stabilized SARS-CoV-2 spike reveal differential immunogenicity in humans
In response to the COVID-19 pandemic, multiple vaccines were developed using platforms such as viral vectors and mRNA technology. Here, we report humoral and cellular immunogenicity data from human phase 1 clinical trials investigating two recombinant Modified Vaccinia virus Ankara vaccine candidates, MVA-SARS-2-S and MVA-SARS-2-ST, encoding the native and the prefusion-stabilized SARS-CoV-2 spike protein, respectively. MVA-SARS-2-ST was more immunogenic than MVA-SARS-2-S, but both were less immunogenic compared to licensed mRNA- and ChAd-based vaccines in SARS-CoV-2 naïve individuals. In heterologous vaccination, previous MVA-SARS-2-S vaccination enhanced T cell functionality and MVA-SARS-2-ST boosted the frequency of T cells and S1-specific IgG levels when used as a third vaccination. While the vaccine candidate containing the prefusion-stabilized spike elicited predominantly S1-specific responses, immunity to the candidate with the native spike was skewed towards S2-specific responses. These data demonstrate how the spike antigen conformation, using the same viral vector, directly affects vaccine immunogenicity in humans
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