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51.
María A. Chiesa Rosanna N. Pioli Mariana V. Cambursano Eligio N. Morandi 《European journal of plant pathology / European Foundation for Plant Pathology》2013,135(2):351-362
Soybean Stem Canker (SSC), caused by Diaporthe phaseolorum var. meridionalis (Dpm), is an important disease of soybean in Argentina. There are five known dominant genes that confer resistance to SSC, Rdm1 to Rdm5. Particularly, Rdm2 was identified in cv. Tracy-M and then it was stabilized in the breeding line T2. The Rdm4 gene was first identified in cv. Hutcheson. More recently it was found that this gene was linked to the Rdm5 gene, defining the Rdm4-5 resistance region in Hutcheson. The objective of this work was to analyze the behaviour of the dominant Rdm2, Rdm4 and Rdm5 genes interacting with the CE109 and CE112 local physiological races of Dpm, in different susceptible backgrounds (genotypes RA702 and J77-339). Rdm4 and Rdm5 segregated phenotypically as completely dominant genes in the specific interactions with the CE109 and CE112 isolates, respectively, in both susceptible backgrounds. Similarly, Rdm2 segregated as expected for a complete dominant gene in the specific interaction with the CE109 isolate, in both susceptible backgrounds. However, when interacting with the CE112 isolate, the Rdm2 gene did not segregate as expected for a completely dominant gene, neither in RA702 nor in J77-339 susceptible background. The distorted segregation of the Rdm2 gene was due to incomplete penetrance. To the best of our knowledge this is the first report documenting changes in the degree of penetrance of a soybean resistance gene (Rdm2) depending upon the physiological race of Dpm which interacts with and the genetic background in which the Rdm gene is being expressed. 相似文献
52.
Edson Luiz Foletto Suellen Battiston Gabriela Carvalho Collazzo Mariana Moro Bassaco Marcio Antonio Mazutti 《Water, air, and soil pollution》2012,223(9):5773-5779
Nanocomposite of CeO2?CSnO2 containing different CeO2 contents was prepared by coprecipitation process. The material obtained was characterized by X-ray diffraction and N2 adsorption?Cdesorption isotherms. Its photocatalytic activity was tested in the degradation of azo dye of leather, Direct Black 38, in aqueous solution under sunlight. The photocatalytic activity of the coupled CeO2?CSnO2 oxide ranged depending on the CeO2 contents. The optimum amount of CeO2 for the synthesis of CeO2?CSnO2 was 7?wt.% since the nanoparticles showed high photocatalytic activity in the degradation of the dye, similar to that of the TiO2?CP25 photocatalyst. The kinetics of photocatalytic degradation and total organic carbon removal under sunlight were found to follow a first-order rate law. The results indicated that CeO2?CSnO2 can be used for the removal of dyes from wastewater. 相似文献
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55.
Sá e Silva M Mathieu-Benson C Kwon YK Pantin-Jackwood M Swayne DE 《Avian diseases》2011,55(3):459-461
Two different wild duck species common in Chile and neighboring countries, Chiloe wigeon (Anas sibilatrix) and cinnamon teal (Anas cyanoptera), were intranasally inoculated with 10(6) mean embryo infective dose (EID50) of the H7N3 low pathogenicity (LP) avian influenza virus (AIV) (A/chicken/Chile/176822/02) or high pathogenicity (HP) AIV (A/chicken/Chile/ 184240-1/02), in order to study the infectivity and pathobiology of these viruses. None of the virus-inoculated ducks had clinical signs or died, but most seroconverted by 14 days postinoculation (DPI), indicating a productive virus infection. Both LPAIV and HPAIV were isolated from oral swabs from two of six Chiloe wigeons and from oral and/or cloacal swabs from all five of the cinnamon teal at 2 DPI. Both LPAIV and HPAIV were efficiently transmitted to cinnamon teal contacts but not to Chiloe wigeon contacts. This study demonstrates that the cinnamon teal and Chiloe wigeons were susceptible to infection with both Chilean H7N3 LPAIV and HPAIV, but only the cinnamon teal showed contact transmission of the virus between birds, suggesting that the cinnamon teal has the potential to be a reservoir for these viruses, especially the LPAIV, as was demonstrated in 2001 with isolation of a genetically related H7N3 LPAIV strain in a cinnamon teal in Bolivia. However, the definitive source of the H7N3 Chilean LPAIV still remains unknown. 相似文献
56.
Kuehn CC Oliveira LG Santos CD Augusto MB Toldo MP do Prado JC 《Veterinary parasitology》2011,177(3-4):242-246
DHEA, a steroid hormone synthesized from cholesterol by cells of the adrenal cortex, plays an essential role in enhancing the host's resistance to different experimental infections. Receptors for this hormone can be found in distinct immune cells (especially macrophages) that are known to be the first line defense against Trypanosoma cruzi infection. These cells operate through an indirect pathway releasing nitric oxide (NO) and cytokines such TNF-α and IL-12 which in turn trigger an enhancement of natural killer cells and lymphocytes which finally secrete pro and anti-inflammatory cytokines. The effects of pre- and post-infection DHEA treatment on production of IL-12, TNFα and NO were evaluated. T. cruzi infected macrophages post treated with DHEA displayed enhanced concentrations of TNF-α, IL-12 and NO. Probably, the mechanisms that induced the production of cytokines by infected cells are more efficient when the immune system has been stimulated first by parasite invasion, suggesting that the protective role of DHEA is greater when administered post infection. 相似文献
57.
Breijo M Isnardi F Brauer M Schenker R Ferrari M Ferreira AM 《Veterinary parasitology》2011,181(2-4):341-344
The aim of this work was to evaluate the potential of lufenuron, a benzylphenylurea with ability to interfere with the formation of insect exoskeleton, as a therapeutic drug for larval echinococcosis (hydatid disease). For this purpose lufenuron, alone or in combination with albendazole, was administered to CD1 mice bearing Echinococcus granulosus hydatid cysts in the peritoneal cavity. Neither of the drugs alone was able to exert parasiticidal effects. However, in combination with albendazole, lufenuron reduced the growth of cysts (30-40% in cyst diameter respect to control, p<0.05). This effect was associated with ultrastructural alterations of the hydatid cyst wall and a reduction of the content of myo-inositol-hexakisphosphate, the major component of the electron dense granules of the laminated layer. Overall, this work provides evidence that lufenuron could represent a useful compound for the use in chemotherapy against larval echinococcosis, by enhancing albendazole parasiticidal activity. 相似文献
58.
This paper elaborates, analyzes, and partly defends the normative and empirical foundations of a “social ecology” model for natural habitat and resource management. This model treats human societies as being irreducibly integrated with the natural systems in which they are embedded. It argues that any concept of biodiversity necessarily embodies cultural values for it to be operationalized for conservation decisions. It accepts the legitimacy of tradeoffs between biodiversity conservation and other values including human resource development. It prioritizes local control of decisions in regions which are often targeted by Northern conservationists: areas of the South, where cultural choices have led to the persistence of high biodiversity. This model is used to analyze an ongoing dispute over biodiversity conservation and natural resource control in Perú: the conflict over Kandozi territory in the Abanico del Pastaza. What the Kandozi want is more than just a rejection of what has been criticized as the national park/fortress model of conservation. It consists of an assertion of local institutionalized control over traditional lands which goes well beyond the purview of the usual alternative of the fortress model: the biosphere reserve model of external and internal joint control of natural resources. To the remarkable extent that Kandozi resource management practices have succeeded in maintaining biotic richness and variety in spite of multiple encroachments, the empirical evidence demands that today’s conservationists pay adequate attention to these practices and the social institutions in which they are embedded. But, beyond such prudential concerns, the social ecology model of habitat conservation accepts the normative claims that resident communities should have control over their lands and livelihoods and that they should be allowed to maintain their habitats as cultural landscapes of their choice. 相似文献
59.
Mariana Cecilia Fernández Flavio Hernán Gutiérrez Boem Gerardo Rubio 《植物养料与土壤学杂志》2011,174(4):673-677
Despite a general consent about the beneficial contribution of arbuscular mycorrhizal fungi (AMF) on natural ecosystems, there is an intense debate about their role in agricultural systems. In this work, soybean (Glycine max L.) and sunflower (Helianthus annuus L.) field plots with different P availabilities were sampled across the Pampean Region of Argentina (> 150 samples from Mollisols) to characterize the relationship between available soil P and indigenous mycorrhizal colonization. A subsequent pot experiment with soybean and sunflower was carried out to evaluate the effect of P supply (0, 12, and 52 mg P kg–1) and AMF inoculation on AMF colonization and crop responsiveness to P in a Mollisol. Both crops showed high AMF colonization in the field (average: 55% for soybean and 44% for sunflower). While mycorrhizal colonization in soybean was significantly and negatively related to available soil P, no such trends were apparent in sunflower. Also, total biomass was 3.5 and 2.0 times higher in mycorrhizal than in nonmycorrhizal pot‐grown soybean under low‐ and medium‐P conditions, respectively. Sunflower, on the other hand, did not benefit from AMF symbiosis under medium and high P supply. While mycorrhization stimulated P‐uptake efficiency in soybean, the generally high P efficiency in sunflower was not associated with AMF symbiosis. 相似文献
60.
Abias Santos Silva Luiz Gustavo Ribeiro Pereira Márcio dos Santos Pedreira Fernanda Samarini Machado Mariana Magalhães Campos Cristina Simões Cortinhas Tiago Sabella Acedo Rafael Dantas dos Santos João Paulo Pacheco Rodrigues Rogério Martins Maurício Thierry Ribeiro Tomich 《Journal of animal physiology and animal nutrition》2020,104(1):76-87
The effect of exogenous amylase on the in vitro rumen digestion kinetics of whole-crop maize silage made from dent (RB9004) or flint grain type (RB9308) was evaluated at different phenological stages: soft dough (SOD), early dent (EAD), ½ milkline (½M) and ¾ milkline (¾M). Forage was harvested from 70 to 110 days after sowing. Two rumen-cannulated cows receiving or not exogenous amylase (0.7 g/kg dry matter—DM, provided to achieve 396 kilo Novo units of amylase activity/kg of TMR DM) were used as donor of ruminal fluid. The in vitro gas production kinetics was evaluated according to a dual-pool logistic model. The chemical composition and gas production kinetics were affected by the hybrid and phenological stages. The flint hybrid had lower range for chemical analysis among physiological stages. Harvesting at ½M and ¾M improved DM content, bromatological composition and silage quality parameters compared to dent or flint types. Amylase (i) increased methane (CH4) production and in vitro dry matter digestibility (IVDMD) in ½M stage, (ii) improved digestion kinetics by reducing lag time and increasing total gas production and fermentation rates of non-fibrous carbohydrates (NFC) and fibrous carbohydrates (FC), and (iii) increased extent and fermentation rate of NFC and increased fermentation rate of FC fraction in whole-crop maize silages produced from dent or flint types in all phenological stages. Harvesting between ½M and ¾M is the best phenological stage to improve chemical composition and silage quality parameters. Exogenous amylase showed improvements on fibre digestion of silages at ½M and ¾M phenological stages in both grain types of corn. 相似文献