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41.
I?igo Zuberogoitia Jose Antonio Martínez Ainara Azkona Jose Enrique Martínez I?aki Castillo Jabi Zabala 《Journal of Ornithology》2009,150(1):95-101
Methods of evaluating population trends have recently received particular attention because of perceived declines in several
species during the twentieth century. We have studied demographic traits of the peregrine falcon (Falco peregrinus) population in Bizkaia (Northern Spain) for 11 years. This species suffered a severe decline in the 1950s and 1960s and started
to recover in the 1980s and 1990s, although the recovery trends differed between areas. In our study area the peregrine falcon
density is one of the highest found in Spain. The frequency of juvenile breeders was 2.0%, the mean age at first breeding
being 3.7 calendar years for males and 4.0 cy for females. The territorial fidelity was at least 3.4 years for males and 3.7 years
for females. Females dispersed on average 80.5 km and males 51.8 km during their pre-breeding movements, whilst distance between
birthplace and breeding territories was on average 108.5 km for females and 64.5 km for males. We studied the relationships
between adult turnover, recruitment age, territorial fidelity and dispersal in a healthy population in order to establish
population dynamics. A combination of these parameters, not just age at first breeding, could be used as a potential early
warning signal indicating future changes, prompting their consequences to be evaluated. This approach could lead to the reclassification
of the large-scale health of a population. Its utilization would allow resources to be directed into helping “ailing” subpopulations,
detecting causes of decline, and developing adequate recovery strategies. 相似文献
42.
Denitrification activity of Bradyrhizobium sp. isolated from Argentine soybean cultivated soils 总被引:1,自引:0,他引:1
Leticia Andrea Fernández Elda Beatriz Perotti Marcelo Antonio Sagardoy Marisa Anahí Gómez 《World journal of microbiology & biotechnology》2008,24(11):2577-2585
Two hundred and fifty strains, all of them representatives of native Bradyrhizobium sp., isolated from soils cultivated with soybean have been characterized by their denitrification activity. In addition,
the denitrification potential of those soils was also measured by evaluating the most-probable-number (MPN) of denitrifying
bacteria and the denitrification enzyme assay (DEA). Of the 250 isolates tested, 73 were scored as probable denitrifiers by
a preliminary screening method. Only 41 were considered denitrifiers because they produced gas bubbles in Durham tubes, cultures
reached an absorbance of more than 0.1 and NO3− and NO2− were not present. Ten of these 41 were selected to confirm denitrification and to study denitrification genes. According
to N2O production and cell protein concentration with NO3−, the isolates could be differentiated in three categories of denitrifiers. The presence of the napA, nirK, norC and nosZ genes was detected by production of a diagnostic PCR product using specific primers. RFLP from the 16S-23S rDNA spacer region
(IGS) revealed that denitrifiers strains could be characterized as Bradyrhizobium japonicum and strains which were non-respiratory denitrifiers as B. elkanii. 相似文献
43.
Florinda Meléndez-Rodríguez Andrés A. Urrutia Doriane Lorendeau Gianmarco Rinaldi Olga Roche Nuray Böğürcü-Seidel Marta Ortega Muelas Claudia Mesa-Ciller Guillermo Turiel Antonio Bouthelier Pablo Hernansanz-Agustín Ainara Elorza Elia Escasany Qilong Oscar Yang Li Mar Torres-Capelli Daniel Tello Esther Fuertes Enrique Fraga Julián Aragonés 《Cell reports》2019,26(9):2257-2265.e4
44.
Sagardoy R Morales F Rellán-Álvarez R Abadía A Abadía J López-Millán AF 《Journal of plant physiology》2011,168(7):730-733
The effects of Zn excess on carboxylate metabolism were investigated in sugar beet (Beta vulgaris L.) plants grown hydroponically in a growth chamber. Root extracts of plants grown with 50 or 100 μM Zn in the nutrient solution showed increases in several enzymatic activities related to organic acid metabolism, including citrate synthase and phosphoenolpyruvate carboxylase, when compared to activities in control root extracts. Root citric and malic acid concentrations increased in plants grown with 100 μM Zn, but not in plants grown with 50 μM Zn. In the xylem sap, plants grown with 50 and 100 μM Zn showed increases in the concentrations of citrate and malate compared to the controls. Leaves of plants grown with 50 or 100 μM Zn showed increases in the concentrations of citric and malic acid and in the activities of citrate synthase and fumarase. Leaf isocitrate dehydrogenase increased only in plants grown with 50 μM Zn when compared to the controls. In plants grown with 300 μM Zn, the only enzyme showing activity increases in root extracts was citrate synthase, whereas the activities of other enzymes decreased compared to the controls, and root citrate concentrations increased. In the 300 μM Zn-grown plants, the xylem concentrations of citric and malic acids were higher than those of controls, whereas in leaf extracts the activity of fumarase increased markedly, and the leaf citric acid concentration was higher than in the controls. Based on our data, a metabolic model of the carboxylate metabolism in sugar beet plants grown under Zn excess is proposed. 相似文献
45.
The monitoring of an experimental feeding station established in northern Spain allowed the evaluation of how this type of resource, predictable in space but not in time, was exploited by a guild of avian scavengers in relation to factors such as season, hour of disposal and presence of the dominant species. The presence of Egyptian Vultures Neophron percnopterus at carcasses was more likely during spring, and richness and diversity of avian scavengers was lower during the summer and when Griffon Vultures Gyps fulvus arrived earlier. The temporal unpredictability of the resource may favour exploitation by smaller and less competitive scavengers. New European regulations may present an opportunity to develop effective conservation measures to support functional scavenger assemblages. 相似文献
46.
Selva N Cortés-Avizanda A Lemus JA Blanco G Mueller T Heinrich B Donázar JA 《Biology letters》2011,7(4):608-610
Many long-lived avian species adopt life strategies that involve a gregarious way of life at juvenile and sub-adult stages and territoriality during adulthood. However, the potential associated costs of these life styles, such as stress, are poorly understood. We examined the effects of group living, sex and parasite load on the baseline concentration of faecal stress hormone (corticosterone) metabolites in a wild population of common ravens (Corvus corax). Corticosterone concentrations were significantly higher in non-breeding gregarious ravens than in territorial adults. Among territorial birds, males showed higher stress levels than their mates. Parasite burdens did not affect hormone levels. Our results suggest a key role of the social context in the stress profiles of the two population fractions, and that group living may be more energetically demanding than maintaining a territory. These findings have implications for understanding hormonal mechanisms under different life styles and may inspire further research on the link between hormone levels and selective pressures modulating gregarious and territorial strategies in long-lived birds. 相似文献
47.
Conservation strategies for long-lived vertebrates require accurate estimates of parameters relative to the populations' size, numbers of non-breeding individuals (the "cryptic" fraction of the population) and the age structure. Frequently, visual survey techniques are used to make these estimates but the accuracy of these approaches is questionable, mainly because of the existence of numerous potential biases. Here we compare data on population trends and age structure in a bearded vulture (Gypaetus barbatus) population from visual surveys performed at supplementary feeding stations with data derived from population matrix-modelling approximations. Our results suggest that visual surveys overestimate the number of immature (<2 years old) birds, whereas subadults (3-5 y.o.) and adults (>6 y.o.) were underestimated in comparison with the predictions of a population model using a stable-age distribution. In addition, we found that visual surveys did not provide conclusive information on true variations in the size of the focal population. Our results suggest that although long-term studies (i.e. population matrix modelling based on capture-recapture procedures) are a more time-consuming method, they provide more reliable and robust estimates of population parameters needed in designing and applying conservation strategies. The findings shown here are likely transferable to the management and conservation of other long-lived vertebrate populations that share similar life-history traits and ecological requirements. 相似文献
48.
Fernandez-Jimenez N Castellanos-Rubio A Plaza-Izurieta L Gutierrez G Irastorza I Castaño L Vitoria JC Bilbao JR 《PloS one》2011,6(12):e28910
The possible implication of copy number variation (CNV) in the genetic susceptibility to human disease needs to be assessed using robust methods that can be applied at a population scale. In this report, we analyze the performance of the two major techniques, quantitative PCR (qPCR) and paralog ratio test (PRT), and investigate the influence of input DNA amount and template integrity on the reliability of both methods. Analysis of three genes (PRELID1, SYNPO and DEFB4) in a large sample set showed that both methods are prone to false copy number assignments if sufficient attention is not paid to DNA concentration and quality. Accurate normalization of samples is essential for reproducible qPCR because it avoids the effect of differential amplification efficiencies between target and control assays, whereas PRT is generally more sensitive to template degradation due to the fact that longer amplicons are usually needed to optimize sensitivity and specificity of paralog sequence PCR. The use of normalized, high quality genomic DNA yields comparable results with both methods. 相似文献
49.
Katharina Imkeller Giulia Ambrosi Nancy Klemm Ainara Claveras Cabezudo Luisa Henkel Wolfgang Huber Michael Boutros 《Molecular systems biology》2022,18(8)
Wnt pathways are important for the modulation of tissue homeostasis, and their deregulation is linked to cancer development. Canonical Wnt signaling is hyperactivated in many human colorectal cancers due to genetic alterations of the negative Wnt regulator APC. However, the expression levels of Wnt‐dependent targets vary between tumors, and the mechanisms of carcinogenesis concomitant with this Wnt signaling dosage have not been understood. In this study, we integrate whole‐genome CRISPR/Cas9 screens with large‐scale multi‐omic data to delineate functional subtypes of cancer. We engineer APC loss‐of‐function mutations and thereby hyperactivate Wnt signaling in cells with low endogenous Wnt activity and find that the resulting engineered cells have an unfavorable metabolic equilibrium compared with cells which naturally acquired Wnt hyperactivation. We show that the dosage level of oncogenic Wnt hyperactivation impacts the metabolic equilibrium and the mitochondrial phenotype of a given cell type in a context‐dependent manner. These findings illustrate the impact of context‐dependent genetic interactions on cellular phenotypes of a central cancer driver mutation and expand our understanding of quantitative modulation of oncogenic signaling in tumorigenesis. 相似文献
50.
Ana-Flor López-Millán Ruth Sagardoy María Solanas Anunciación Abadía Javier Abadía 《Environmental and Experimental Botany》2009,65(2-3):376-385
The effects of Cd have been investigated in tomato (Lycopersicon esculentum) plants grown in a controlled environment in hydroponics, using Cd concentrations of 10 and 100 μM. Cadmium treatment led to major effects in shoots and roots of tomato. Plant growth was reduced in both Cd treatments, leaves showed chlorosis symptoms when grown at 10 μM Cd and necrotic spots when grown at 100 μM Cd, and root browning was observed in both treatments. An increase in the activity of phosphoenolpyruvate carboxylase, involved in anaplerotic fixation of CO2 into organic acids, was measured in root extracts of Cd-exposed plants. Also, significant increases in the activities of several enzymes from the Krebs cycle were measured in root extracts of tomato plants grown with Cd. In leaf extracts, significant increases in citrate synthase, isocitrate dehydrogenase and malate dehydrogenase activities were also found at 100 μM Cd, whereas fumarase activity decreased. These data suggest that at low Cd supply (10 μM) tomato plants accumulate Cd in roots and this mechanism may be associated to an increased activity in the PEPC–MDH–CS metabolic pathway involved in citric acid synthesis in roots. Also, at low Cd supply some symptoms associated with a moderate Fe deficiency could be observed, whereas at high Cd supply (100 μM) effects on growth overrule any nutrient interaction caused by excess Cd. Cadmium excess also caused alterations on photosynthetic rates, photosynthetic pigment concentrations and chlorophyll fluorescence, as well as in nutrient homeostasis. 相似文献