1,052 research outputs found
Clot Formation in the Sipunculid Worm Themiste petricola: A Haemostatic and Immune Cellular Response
Clot formation in the sipunculid Themiste petricola, a coelomate nonsegmented marine worm without a circulatory system, is a cellular response that creates a haemostatic mass upon activation with sea water. The mass with sealing properties is brought about by homotypic aggregation of granular leukocytes present in the coelomic fluid that undergo a rapid process of fusion and cell death forming a homogenous clot or mass. The clot structure appears to be stabilized by abundant F-actin that creates a fibrous scaffold retaining cell-derived components. Since preservation of fluid within the coelom is vital for the worm, clotting contributes to rapidly seal the body wall and entrap pathogens upon injury, creating a matrix where wound healing can take place in a second stage. During formation of the clot, microbes or small particles are entrapped. Phagocytosis of self and non-self particles shed from the clot occurs at the clot neighbourhood, demonstrating that clotting is the initial phase of a well-orchestrated dual haemostatic and immune cellular response
Livestock Drugs and Disease: The Fatal Combination behind Breeding Failure in Endangered Bearded Vultures
There is increasing concern about the impact of veterinary drugs and livestock pathogens as factors damaging wildlife health, especially of threatened avian scavengers feeding upon medicated livestock carcasses. We conducted a comprehensive study of failed eggs and dead nestlings in bearded vultures (Gypaetus barbatus) to attempt to elucidate the proximate causes of breeding failure behind the recent decline in productivity in the Spanish Pyrenees. We found high concentrations of multiple veterinary drugs, primarily fluoroquinolones, in most failed eggs and nestlings, associated with multiple internal organ damage and livestock pathogens causing disease, especially septicaemia by swine pathogens and infectious bursal disease. The combined impact of drugs and disease as stochastic factors may result in potentially devastating effects exacerbating an already high risk of extinction and should be considered in current conservation programs for bearded vultures and other scavenger species, especially in regards to dangerous veterinary drugs and highly pathogenic poultry viruses
Targeting Mitophagy in Combined Therapies of Haematological Malignancies
Mitophagy is a selective form of autophagy that eliminates mitochondria and is part of a larger network of mitochondrial quality control processes that respond to mitochondrial damage. Treatment of haematological malignancies often involves drugs that ultimately cause cell death by mitochondrial injury and initiation of apoptosis. Thus, mitophagy is a potential cause of resistance to anticancer drugs that target the mitochondria (mitocans). Since mitophagy is integrated to mitochondrial biogenesis, mitochondrial fission and fusion, the bioenergetics profile and metabolic reprogramming of tumour cells, the blockage of mitophagy may not be sufficient to overcome resistance. In addition, the mitochondrial unfolded protein response and the outer mitochondrial membrane-associated degradation have extensive crosstalk with mitophagy, and advanced forms of neoplasms will require targeting both systems. Proteasome inhibitors and vinca alkaloids target many of the critical steps involved in resistance to mitocans, while inducers of mitochondrial turnover (biogenesis and mitophagy) like valproic acid have a variable effect depending on metabolic reprograming and the activity of oxidative phosphorylation of tumour cells. Here we discuss the mechanisms of mitophagy and its associated mechanisms, and discuss its application to the rationale of targeted combined therapies of low- and high-grade B-cell neoplasms
The PHA Test Reflects Acquired T-Cell Mediated Immunocompetence in Birds
cological immunology requires techniques to reliably measure immunocompetence in wild vertebrates. The PHA-skin test, involving subcutaneous injection of a mitogen (phytohemagglutinin, PHA) and measurement of subsequent swelling as a surrogate of T-cell mediated immunocompetence, has been the test of choice due to its practicality and ease of use in the field. However, mechanisms involved in local immunological and inflammatory processes provoked by PHA are poorly known, and its use and interpretation as an acquired immune response is currently debated.) and plasma proteins circulating in the bloodstream, potentially involved in the immunological and inflammatory processes, through flow cytometry and electrophoresis.Our results showed stronger responses after a second PHA injection, independent of species, time elapsed and changes in body mass of birds between first and second injections, thus supporting the adaptive nature of this immune response. Furthermore, the concomitant changes in the plasma concentrations of T-lymphocyte subsets and globulins indicate a causal link between the activation of the T-cell mediated immune system and local tissue swelling.These findings justify the widespread use of the PHA-skin test as a reliable evaluator of acquired T-cell mediated immunocompetence in diverse biological disciplines. Further experimental research should be aimed at evaluating the relative role of innate immunocompetence in wild conditions, where the access to dietary proteins varies more than in captivity, and to ascertain how PHA responses relate to particular host-parasite interactions
Habitat, world geographic range, and embryonic development of hosts explain the prevalence of avian hematozoa at small spatial and phylogenetic scales
The factors explaining interspecific differences in prevalences of blood parasites in birds are poorly known. We simultaneously assessed 20 social, ecological, life history, and sampling-related variables that could influence hemoparasite prevalences among diurnal birds of prey in Spain. Our results show that multiple factors are responsible for the studied host-parasite association. We confirmed for the first time that prevalence is inversely correlated to the embryonic development period, and thus probably to immune performance, even among closely related birds. Macrohabitat features related to vector availability are also important, prevalences being higher in species breeding in forested habitats. Finally, prevalence is positively correlated with the host's world geographic range. We hypothesize that larger geographic ranges offered more opportunities for host-vector-hemoparasite associations to become established. The results from our multivariate analyses differ from those obtained through univariate ones, showing that all potential factors should be assessed jointly when testing any ecological or evolutionary hypothesis dealing with parasites.Peer Reviewe
Sobre el teorema integral de cauchy
En tal época consideramos que la demostración que aquí presentamos, aunque analítica en carácter, no era sencilla (por depender de los Lemas 1.1 y 1.2), y por lo tanto era poco práctica para fines didácticos. Sin embargo, como hemos notado que la demostración de Artin no es fácilmente asimilada por los estudiantes, como consideramos que el Teorema 1.1 es útil para muchos propósitos (v. [3]), y como hemos observado que el interés por encontrar nuevas demostraciones del teorema de Cauchy, o por simplificar las existentes (v. [8],[9]), aún persiste, hemos decidido presentarla ahora, tanto más cuanto que hemos logrado una pequeña simplificación de la demostración del Lema 1.2 con respecto a la que presentamos en [3].A proof is given of the Cauchy integral theorem for closed I-forms which is more analytical in character than the usual proof of E. Artin
Tracking data and retrospective analyses of diet reveal the consequences of loss of marine subsidies for an obligate scavenger, the andean condor
Over the last century, marine mammals have been dramatically reduced in the world’s oceans. We examined evidence that this change caused dietary and foraging pattern shifts of the Andean condor (Vultur gryphus) in Patagonia. We hypothesized that, after the decrease in marine mammals and the increase in human use of coastlines, condor diet changed to a more terrestrial diet, which in turn influenced their foraging patterns. We evaluated the diet by means of stable isotope analysis (δ13C, δ15N and δ34S) of current (last decade) and historical (1841–1933) feathers. We further evaluated the movement patterns of 23 condors using satellite tracking of individuals. Condors reduced their use of marine-derived prey in recent compared with historical times from 33+13% to less than 8+3% respectively; however, they still breed close to the coast. The average distance between the coast and nests was 62.5 km, but some nests were located close to the sea (less than 5 km). Therefore, some birds must travel up to 86 km from nesting sites, crossing over the mountain range to find food. The worldwide reduction in marine mammal carcasses, especially whales, may have major consequences on the foraging ecology of scavengers, as well as on the flux of marine inputs within terrestrial ecosystems.Fil: Lambertucci, Sergio Agustin. 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; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Navarro, Joan. Consejo Superior de Investigaciones Científicas. Instituto de Ciencias del Mar; EspañaFil: Sanchez Zapata, José A.. Universidad de Miguel Hernández; EspañaFil: Hobson, Keith A.. Environment Canada; CanadáFil: Alarcón, Pablo Angel Eduardo. 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; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Wiemeyer, Guillermo. 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; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Blanco, Guillermo. Consejo Superior de Investigaciones Científicas; EspañaFil: Hiraldo, Fernando. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; EspañaFil: Donázar, José A.. Consejo Superior de Investigaciones Científicas. Estación Biológica de Doñana; Españ
Susceptibility to Infection and Immune Response in Insular and Continental Populations of Egyptian Vulture: Implications for Conservation
BACKGROUND:A generalized decline in populations of Old World avian scavengers is occurring on a global scale. The main cause of the observed crisis in continental populations of these birds should be looked for in the interaction between two factors -- changes in livestock management, including the increased use of pharmaceutical products, and disease. Insular vertebrates seem to be especially susceptible to diseases induced by the arrival of exotic pathogens, a process often favored by human activities, and sedentary and highly dense insular scavengers populations may be thus especially exposed to infection by such pathogens. Here, we compare pathogen prevalence and immune response in insular and continental populations of the globally endangered Egyptian vulture under similar livestock management scenarios, but with different ecological and evolutionary perspectives. METHODS/PRINCIPAL FINDINGS:Adult, immature, and fledgling vultures from the Canary Islands and the Iberian Peninsula were sampled to determine a) the prevalence of seven pathogen taxa and b) their immunocompetence, as measured by monitoring techniques (white blood cells counts and immunoglobulins). In the Canarian population, pathogen prevalence was higher and, in addition, an association among pathogens was apparent, contrary to the situation detected in continental populations. Despite that, insular fledglings showed lower leukocyte profiles than continental birds and Canarian fledglings infected by Chlamydophila psittaci showed poorer cellular immune response. CONCLUSIONS/SIGNIFICANCE:A combination of environmental and ecological factors may contribute to explain the high susceptibility to infection found in insular vultures. The scenario described here may be similar in other insular systems where populations of carrion-eaters are in strong decline and are seriously threatened. Higher susceptibility to infection may be a further factor contributing decisively to the extinction of island scavengers in the present context of global change and increasing numbers of emerging infectious diseases
Chromosome-Level Genome Assembly of the Common Chaffinch (Aves: Fringilla coelebs): A Valuable Resource for Evolutionary Biology
The common chaffinch, Fringilla coelebs, is one of the most common, widespread, and well-studied passerines in Europe, with a broad distribution encompassing Western Europe and parts of Asia, North Africa, and the Macaronesian archipelagos. We present a high-quality genome assembly of the common chaffinch generated using Illumina shotgun sequencing in combination with Chicago and Hi-C libraries. The final genome is a 994.87-Mb chromosome-level assembly, with 98% of the sequence data located in chromosome scaffolds and a N50 statistic of 69.73 Mb. Our genome assembly shows high completeness, with a complete BUSCO score of 93.9% using the avian data set. Around 7.8% of the genome contains interspersed repetitive elements. The structural annotation yielded 17,703 genes, 86.5% of which have a functional annotation, including 7,827 complete universal single-copy orthologs out of 8,338 genes represented in the BUSCO avian data set. This new annotated genome assembly will be a valuable resource as a reference for comparative and population genomic analyses of passerine, avian, and vertebrate evolution
Seed dispersal by macaws shapes the landscape of an Amazonian ecosystem
Seed dispersal is one of the most studied plant–animal mutualisms. It has been proposed that the
dispersal of many large-seeded plants from Neotropical forests was primarily conducted by extinct
megafauna, and currently by livestock. Parrots can transport large fruits using their beaks, but have
been overlooked as seed dispersers. We demonstrate that three macaws (Ara ararauna, A. glaucogularis
and A. severus) are the main dispersers of the large-seeded motacú palm Attalea princeps, which is the
biomass-dominant tree in the Bolivian Amazonian savannas. Macaws dispersed fruits at high rates (75–
100% of fruits) to distant (up to 1200 m) perching trees, where they consumed the pulp and discarded
entire seeds, contributing to forest regeneration and connectivity between distant forests islands. The
spatial distribution of immature palms was positively associated to the proximity to macaws’ perching
trees and negatively to the proximity to cattle paths. The disperser role of livestock, presumably a
substitute for extinct megafauna, had little effect due to soil compaction, trampling and herbivory. Our
results underscore the importance of macaws as legitimate, primary dispersers of large-seeded plants
at long distances and, specifically, their key role in shaping the landscape structure and functioning of
this Amazonian biomePeer reviewe
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