464 research outputs found

    Development of cisgenic apples with durable resistance to apple scab

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    Most of the apple (Malus × domestica) growers are facing serious disease problems with apple scab which is caused by the fungus Venturia inaequalis. Developing a resistant variety in apple through classical breeding is very slow and inefficient. So, we aim at improving existing apple varieties through a new concept called “cisgenesis” which saves time and effort compared to classical breeding. Malus floribunda proved to be a good source of natural scab resistance genes. The genes HcrVf1 and HcrVf2, consisting of promoter, coding and terminator sequences in their natural configuration, were isolated from Malus floribunda and cloned into the binary vector pMF1. Apple cv. ‘Gala’ was transformed with pMF1 containing HcrVf1 and HcrVf2, individually or in combination. pMF1 can be used to obtain marker-free plants by recombinase-based excision of a fragment carrying undesired gene sequences, such as antibiotic-selection marker genes, leaving behind only the gene(s)-of-interest and one recombination site. Using this vector it is therefore possible to stack several genes by retransformation using the same selection procedure. In order to obtain durable resistance, we have the intention to combine different resistance genes from Malus either by stacking them one by one or by introducing them all together in one T-DNA. Performance of all different types of cisgenic plants will be evaluated by monitoring scab resistance levels phenotypically and by determining gene expression profiles through quantitative RT-PC

    Identification and mapping of a new apple scab resistance gene

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    Here we report the identification of a new resistance gene (Vd3) against apple scab (Venturia inaequalis) from the apple selection 1980-015-25 of the breeding program at Plant Research International. This accession also contains the Vf gene. We mapped Vd3, using SSR and DArT markers, on linkage group 1, at a distance of 6 cM from Vf gene, but in repulsion phase to Vf. Based on pedigree analysis and resistance tests, it could be deduced that 1980-015-25 had inherited Vd3 from the founder D3. This gene provides resistance to the highly virulent EU-NL-24 strain of the race 7 of V. inaequalis. This strain has overcome the resistance from both Vf and Vg. However, Vd3 has been not effective against the majority of other V. inaequalis strains we used in our disease test

    Identification and mapping of the novel apple scab resistance gene Vd3

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    Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most devastating diseases for the apple growing in temperate zones with humid springs and summers. Breeding programs around the world have been able to identify several sources of resistance, the Vf from Malus floribunda 821 being the most frequently used. The appearance of two new races of V. inaequalis (races 6 and 7) in several European countries that are able to overcome the resistance of the Vf gene put in evidence the necessity of the combination of different resistance genes in the same genotype (pyramiding). Here, we report the identification and mapping of a new apple scab resistance gene (Vd3) from the resistant selection “1980-015-25” of the apple breeding program at Plant Research International, The Netherlands. This selection contains also the Vf gene and the novel V25 gene for apple scab resistance. We mapped Vd3 on linkage group 1, 1 cM to the south of Vf in repulsion phase to it. Based on pedigree analysis and resistance tests, it could be deduced that 1980-015-25 had inherited Vd3 from the founder “D3.” This gene provides resistance to the highly virulent EU-NL-24 strain of race 7 of V. inaequalis capable of overcoming the resistance from Vf and Vg

    Anomalous Roughening in Experiments of Interfaces in Hele-Shaw Flows with Strong Quenched Disorder

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    We report experimental evidences of anomalous kinetic roughening in the stable displacement of an oil-air interface in a Hele-Shaw cell with strong quenched disorder. The disorder consists on a random modulation of the gap spacing transverse to the growth direction (tracks). We have performed experiments varying average interface velocity and gap spacing, and measured the scaling exponents. We have obtained beta=0.50, beta*=0.25, alpha=1.0, alpha_l=0.5, and z=2. When there is no fluid injection, the interface is driven solely by capillary forces, and a higher value of beta around beta=0.65 is measured. The presence of multiscaling and the particular morphology of the interfaces, characterized by high slopes that follow a L\'evy distribution, confirms the existence of anomalous scaling. From a detailed study of the motion of the oil--air interface we show that the anomaly is a consequence of different local velocities over tracks plus the coupling in the motion between neighboring tracks. The anomaly disappears at high interface velocities, weak capillary forces, or when the disorder is not sufficiently persistent in the growth direction. We have also observed the absence of scaling when the disorder is very strong or when a regular modulation of the gap spacing is introduced.Comment: 14 pages, 17 figure

    Aspectos psicológicos y sociológicos en la alimentación de los deportistas

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    Con el presente articulo queremos describir mediante una revision bibliografica los aspectos que caracterizan los habitos alimentarios en los deportistas y su relacion con la optimizacion del rendimiento y el mantenimiento del estado de salud del deportista. Los factores que influyen en la educacion alimentaria del deportista son varios: habitos alimentarios de la infancia y adolescencia, suplementacion en el deporte, trastornos del comportamiento alimentario y deportistas de alto rendimiento deportivo. Se valora principalmente la ingesta de nutrientes y alimentaria de estos, pero se necesitan conocer sus practicas alimentarias durante entrenamiento—competicion. Cobra importancia las recomendaciones de alimentacion no realizadas por dietistas-nutricionistas, sino por padres y/o entrenadores que pueden ser incorrectas y perjudicar al deportista. Por ello, ha de considerar la valoracion dietetico-nutricional para conocer el contexto social del deportista, ayudandonos a realizar la mejor intervencion en la mejora de la salud y rendimiento deportivo mediante la alimentacion

    Consumer Behavior Analysis and Social Marketing: The Case of Environmental Conservation

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    Consumer behavior analysis represents one development within the behavior-analytic tradition of interpreting complex behavior, in which a specific conceptual framework has been proposed (i.e., the Behavioral Perspective Model). According to this model, consumer behavior occurs at the intersection of a consumer-behavior setting and an individual’s learning history of consumption and is a function of utilitarian (mediated by the product) and informational (mediated by other persons) consequences. The model has been useful in analyses of consumers’ brand choice and reactions to different settings. In the present paper, the model was applied to the interpretation of environmental deleterious behaviors (use of private transportation, consumption of domestic energy, waste disposal, and domestic consumption of water). This application pointed to specific marketing strategies that should be adopted to modify each of these operant classes

    Low-density colloid centrifugation removes bacteria from boar semen doses after spiking with selected species

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    [EN] Single-layer centrifugation (SLC) with a low-density colloid is an efficient method for removing contaminating microorganisms from boar semen while recovering most spermatozoa from the original sample. This study tested the performance of this technique, using 50-ml tubes, by spiking commercial semen doses prepared without antibiotics with selected bacterial species followed by storage at 17 °C. The doses were spiked up to 102/ml CFU (colony forming units) of the bacteria Burkholderia ambifaria, Pseudomonas aeruginosa, and Staphylococcus simulans. The semen was processed by SLC (15 ml of sample and 15 ml of colloid) with the colloid Porcicoll at 20% (P20) and 30% (P30), with a spiked control (CTL) and an unspiked control (CTL0), analyzing microbiology and sperm quality on days 0, 3 and 7. SLC completely removed B. ambifaria and S. simulans, considerably reducing P. aeruginosa and overall contamination (especially P30, ∼104 CFU/ml of total contamination on day 7, median). Sperm viability was lower in P20 and P30 samples at day 0, with higher cytoplasmic ROS. Still, results were similar in all groups on day 3 and reversed on day 7, indicating a protective effect of SLC (possibly directly by removal of damaged sperm and indirectly because of lower bacterial contamination). Sperm chromatin was affected by the treatment (lower DNA fragmentation and chromatin decondensation) and storage (higher overall condensation on day 7 as per chromomycin A3 and monobromobimane staining). In conclusion, SLC with low-density colloids can remove most bacteria in a controlled contamination design while potentially improving sperm quality and long-term storage at practical temperatures.S

    Electronic structure of stoichiometric and Ar+-bombarded ZrO2 determined by resonant photoemission

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    The electronic properties of thermally grown ZrO2 thin films before and after Ar+ bombardment have been studied with resonant photoemission spectroscopy using synchrotron radiation. For stoichiometric ZrO2 thin films the experimental valence-band spectra are in good agreement with the calculated density of states for bulk ZrO2. For both stoichiometric and Ar+-bombarded ZrO2 thin films, resonant photoemission from the valence band was observed when the photon energy was swept through the Zr 4p→4d transition energy. The resonant profile was found to exhibit a maximum at hν=39 eV, followed by a second well-resolved broad maximum around 50 eV. The feature at 39 eV is consistent with resonant enhancement of the Zr 4d states and has been used to identify those regions of the valence band with an important Zr 4d admixture. The results are in good agreement with the calculated Zr 4d partial density of states. The intensity increase observed at hν∼45-50 eV is found to be associated with the nonbonding region of the valence band, although a proper interpretation is needed. In addition, it was found that Ar+ bombardment induces electronic states in the band-gap region and changes in the O 2p valence band. Three distinct emission bands were identified in the band gap as a function of the Ar+ dose. They are associated with the formation of oxygen vacancies and mixed oxidation states due to preferential sputtering of the oxygen atoms. Resonant photoemission of these Ar+-bombarded films demonstrates both the cationic character of the band-gap states and the increase of the cationic contribution to the O 2p valence band.Comisión Interministerial de Ciencia y Tecnología MAT93/0805, MAT94/1039 y PB93-0240Unión Europea ERBCHRXCT 930358 y BESSY-CHGECT93- 002

    Erythropoietin administration partially prevents adipose tissue loss in experimental cancer cachexia models

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    Cancer-associated cachexia is characterized, among other symptoms, by a dramatic loss of both muscle and fat. In addition, the cachectic syndrome is often associated with anemia. The object of the present investigation was to assess the effects of erythropoietin (EPO) treatment on experimental cancer cachexia models. The results clearly show that, in addition to the improvement of the hematocrit, EPO treatment promoted a partial preservation of adipose tissue while exerting negligible effects on muscle loss. Administration of EPO to tumor-bearing animals resulted in a significant increase of lipoprotein lipase (LPL) activity in adipose tissue, suggesting that the treatment favored triacylglycerol (TAG) accumulation in the adipose tissue. In vitro experiments using both adipose tissue slices and 3T3-L1 adipocytes suggests that EPO is able to increase the lipogenic rate through the activation of its specific receptor (EPOR). This metabolic pathway, in addition to TAG uptake by LPL, may contribute to the beneficial effects of EPO on fat preservation in cancer cachexia
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