High-Resolution Mapping of Two Broad-Spectrum Late Blight Resistance Genes from Two Wild Species of the Solanum circaeifolium Group     

Estelle Verzaux  Gert van Arkel  Vivianne G. A. A. Vleeshouwers  Edwin A. G. van der Vossen  Rients E. Niks  Evert Jacobsen  Jack Vossen  Richard G. F. Visser 《Potato Research》2012,55(2):109-123

High levels of resistance to Phytophthora infestans in Solanum are predominantly based on the gene-for-gene interaction. Identification of hitherto unknown R genes is essential for future pyramiding approaches. This could be achieved either through classic introgression breeding or through cisgenesis and could lead to sustainable control of late blight. Here, we report on the mapping of Rpi-cap1 and Rpi-qum1, two late blight R genes identified in the wild species Solanum capsicibaccatum and Solanum circaeifolium ssp. quimense, respectively, to very similar positions on the long arm of chromosome 11. Despite the difficulties encountered for marker development, a high-resolution genetic map with cleaved amplified polymorphic sequence markers was constructed. Furthermore, an R gene cluster-directed profiling approach led to the development of markers that closely linked to or co-segregated with the Rpi-cap1 gene. Both R genes are hypothesized to be homologous to the N gene, a toll-interleukin1 receptor–nucleotide-binding site–leucine-rich repeat domain type of R gene to tobacco mosaic virus from tobacco. To confirm this hypothesis, cloning of Rpi-cap1 and Rpi-qum1 should be pursued. Cloning would also be instrumental to facilitate the introduction of these valuable R genes into potato crops using cisgenic- and marker-assisted breeding approaches.  相似文献   

Paralytic Toxins Accumulation and Tissue Expression of ��-Amylase and Lipase Genes in the Pacific Oyster Crassostrea gigas Fed with the Neurotoxic Dinoflagellate Alexandrium catenella     

Jean-Luc Rolland  Kevin Pelletier  Estelle Masseret  Fabien Rieuvilleneuve  Veronique Savar  Adrien Santini  Zouher Amzil  Mohamed Laabir 《Marine drugs》2012,10(11):2519-2534

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Regeneration of volatile compounds in Fuji apples following ultra low oxygen atmosphere storage and its effect on sensory acceptability     

Altisent R  Graell J  Lara I  López L  Echeverría G 《Journal of agricultural and food chemistry》2008,56(18):8490-8497

The aim of this work was to assess whether extra time spent under AIR conditions after storage in an ultra low oxygen (ULO) atmosphere could allow the regeneration of volatile compound emission without negatively affecting quality parameters and the consumer acceptability of Fuji apples. Fruits were stored for 19 and 30 weeks at 1 degrees C and 92% RH under ULO atmosphere conditions (1 kPa O 2:1 kPa CO 2) or under ULO conditions followed by different periods (2 and 4 weeks) in cold AIR atmosphere (ULO + 2w or ULO + 4w, respectively). Standard quality and emission of volatile compounds were analyzed after storage plus 1 and 7 days at 20 degrees C. Sensory attributes and acceptability were also determined after 7 days at 20 degrees C. The extra period of 30 weeks in an AIR atmosphere after ULO storage resulted in an increase in the concentration of the compounds that most contribute to the flavor of Fuji apples. These fruits were relatively well accepted by consumers despite a slight decline in firmness and acidity.  相似文献   

Long-term storage of Pink Lady apples modifies volatile-involved enzyme activities: consequences on production of volatile esters     

Villatoro C  Echeverría G  Graell J  López ML  Lara I 《Journal of agricultural and food chemistry》2008,56(19):9166-9174

Pink Lady apples were harvested at commercial maturity and stored at 1 degrees C and 92% relative humidity under either air or controlled atmosphere conditions (2 kPa O 2:2 kPa CO 2 and 1 kPa O 2:1 kPa CO 2) for 27 weeks. Data on the emission of volatile compounds and on the activity of some related enzymes in both skin and flesh tissues were obtained during subsequent shelf life at 20 degrees C. Major effects of storage atmosphere and poststorage period were observed on the emission of volatile esters and their precursors. Changes in the production of volatile esters were partly due to alterations in the activity of alcohol o-acyltransferase, but the specific esters emitted by fruit after storage also resulted largely from modifications in the supply of the corresponding substrates. Samples stored under air were characterized by higher availability of acetaldehyde, whereas those stored under CA showed enhanced emission of the alcohol precursors ethanol and 1-hexanol (2 kPa O 2) and 1-butanol (1 kPa O 2), with accordingly higher production of ethyl, hexyl, and butyl esters. Multivariate analysis revealed that a large part of the observed differences in precursor availability arose from modifications in the activity of the enzymes considered. Higher pyruvate decarboxylase activity in air-stored fruit possibly accounted for higher acetaldehyde levels in these samples, while storage under 1 kPa O 2 led to significantly decreased lipoxygenase activity and thus to lessened production of 1-hexanol and hexyl esters. Low acetaldehyde availability together with enhanced hydroperoxide lyase and alcohol dehydrogenase levels in these fruits are suggested to have led to higher emission of 1-butanol and butyl esters.  相似文献   

Shelf life modeling of photosensitive food: the case of colored beverages     

Manzocco L  Kravina G  Calligaris S  Nicoli MC 《Journal of agricultural and food chemistry》2008,56(13):5158-5164

A new approach to shelf life modeling of photosensitive foods was developed taking into consideration the example of a saffron-containing yellow beverage highly prone to oxidative photobleaching. The beverage was exposed to different light levels at increasing temperatures. During exposure, samples were analyzed for bleaching rate, pigment content, and pigment degradation products. The results obtained clearly showed that shelf life testing of light-sensitive foods must take into proper account the effect of light. In addition, for these foods, shelf life models based on the sole accelerating effect of temperature may be misleading. By contrast, the concomitant exploitation of the accelerating effects of both light and temperature was used to develop and validate a simple model correctly predicting the shelf life of the beverage under actual storage conditions. The methodology proposed may allow solving of the difficult task of predicting shelf life of photosensitive foods usually marketed in the presence of light.  相似文献   

Quantification of individual phosphorus species in sediment: a sequential conversion and extraction method     

J. F. Oxmann  Q. H. Pham  R. J. Lara 《European Journal of Soil Science》2008,59(6):1177-1190

Common sequential phosphorus (P) extraction methods are not specific to particular chemical species and have several limitations. This work presents the first chemical method for quantification of individual mineral and sorbed P species. It was developed by combining a conversion technique with a sequential extraction procedure. Mangrove sediments with different characteristics were incubated in pH‐adjusted 0.01 M CaCl₂ with and without reference material additions of octacalcium phosphate (Ca₈H₂(PO₄)₆·5H₂O; OCP), hydroxyapatite (Ca₅(PO₄)₃OH), strengite (FePO₄·2H₂O) or variscite (AlPO₄·2H₂O). The changes in soluble phosphate concentration were measured in the supernatant solution, while pH‐induced variations in P composition were determined by subsequent sequential extraction of the sediments. Dissolved phosphate concentration was controlled by adsorption below pH 7.8. Above this pH, soluble phosphate concentration was governed by OCP, which was qualitatively determined by plotting the experimental values of pH + pH₂PO₄ and pH – 0.5 pCa on a solubility diagram including the isotherms of known crystalline phosphate compounds. In contrast to the often‐predicted slow dissolution rate of crystalline phosphates in soils or sediments, drastic changes in P composition by dissolution, precipitation and adsorption processes were detected after 7 days. These were mainly not observed indirectly by changes in dissolved phosphate through adsorption effects, but were determined quantitatively by subsequent sequential extraction, thus enabling the quantification of individual species. Evaluation of the method was performed by standard addition experiments. Besides P species quantification, the method provides the means for other applications, such as the determination of P mineral dissolution kinetics in soils and sediments, the prediction of P composition in changing environmental settings and the refinement of theoretical models of phosphate solubility in soil and sedimentary environments.  相似文献   

Resistance to metalaxyl-M and cymoxanil in a dominant clonal lineage of <Emphasis Type="Italic">Phytophthora infestans</Emphasis> in Huánuco,Peru, an area of continuous potato production     

Wilmer Pérez  Johanna Lara  Gregory A. Forbes 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(1):87-95

Fifty-eight isolates of Phytophthora infestans were evaluated in vitro and on detached leaves of potato for their sensitivities to metalaxyl-M and cymoxanil. The isolates belonged to the clonal lineage, EC-1, which is dominant on potato in Peru and Ecuador. All isolates were collected in Huánuco, Peru, an area of year-round potato production, where the potential for development of fungicide resistance is high. All isolates were resistant to metalaxyl-M, with in vitro EC₅₀ values ranging from 468.30—813.57 mg l⁻¹. In contrast, we found no evidence for resistance to cymoxanil for which in vitro EC₅₀ values ranged from 0.03—1.11 mg l⁻¹. Resistance to each fungicide was also evaluated for five isolates in a detached leaf assay in which the fungicide was sprayed on the leaf surface prior to inoculation. With metalaxyl-M, the range of EC₅₀ values was 158.85—828.29 mg l⁻¹, similar to that for the in vitro assay. For cymoxanil, EC₅₀ values ranged from 1.41 to 2.31 mg l⁻¹, which was higher than in the in vitro assay but still two orders of magnitude lower than the concentration applied by farmers in the field.  相似文献   

Kinetics of leucine-lysine peptide adsorption and desorption at -CH3 and -COOH terminated alkylthiolate monolayers     

Apte JS  Gamble LJ  Castner DG  Campbell CT 《Biointerphases》2010,5(4):97-104

The kinetics of adsorption and desorption of two highly asymmetrical model peptides were studied at methyl- and carboxylic acid-terminated alkylthiolate self-assembled monolayer (SAM) surfaces on gold. The model peptides were leucine-lysine (LK), α-helical (LKα14), and β-strand (LKβ15) peptides that have a well-defined secondary structure with the leucines localized on one side and the lysines on the other side. These secondary structures were previously shown to be maintained after adsorption and to control LK peptide orientation on these surfaces. The kinetics of peptide adsorption were analyzed by surface plasmon resonance as a function of peptide solution concentrations at pH 7.4. Peptide desorption was measured by rinsing with a buffer at various times along the adsorption curve. Both peptides had a saturation coverage of approximately 1 ML (monolayer) on the carboxyl SAM. Both peptides exhibited mostly irreversible binding on both surfaces, but the LKα14 peptide showed some limited reversible binding. Reversibly bound peptides could be in the second adlayer interacting only with peptides in the first layer or peptides interacting with a partially covered adsorption site and therefore not able to fully bind to the SAM surface. The near complete lack of reversible binding for LKβ15 is possibly due to strong peptide-peptide hydrogen bonding in β-sheet structures within the adsorbed layer. For a given dose of either peptide, much less peptide adsorbed on the methyl SAMs. The adsorption rate of irreversibly bound LKα14 on carboxylic acid SAMs was first-order with respect to solution concentration. Both peptides showed nucleation-like adsorption kinetics on the carboxylic acid SAM, indicating that peptide-peptide bonding is needed to stabilize the adsorbed layer. Adsorption on the methyl SAM was much lower in quantity for both peptides and seemed to require prior aggregation of the proteins in solution, at least for LKβ15.  相似文献   

Detecting reproductive system abnormalities of broiler breeder roosters at different ages          下载免费PDF全文

MA Lagares  R Ecco  NRS Martins  LJC Lara  JSR Rocha  DAR Vilela  VM Barbosa  PF Mantovani  JFV Braga  IS Preis  VA Gheller  PC Cardeal  NC Baião 《Reproduction in domestic animals》2017,52(1):67-75

The objective of this study was to detect the reasons of rooster's fertility decrease at 50 weeks of age. Therefore, the reproductive system of broiler breeder roosters was laparoscopic, macroscopic and histopathology evaluated, and a comparison of the anatomical aspect with the sperm analysis and birds’ age was realized. Cobb roosters (n = 59) were distributed into two groups (30 and 50 weeks). Evaluations were performed with laparoscopy, macroscopy and histopathology, and seminal quality, blood serum testosterone concentration and weight were also determined. The old roosters presented smaller testicle size, higher intensity epididymal lithiasis and lower testicle sperm production, compared to the young roosters. The use of the endoscope could easily distinguish a normal‐sized testicle than an atrophic one. Four old roosters with severe testicular atrophy did not show spermatogenesis, although three still had sperm in the ejaculate. This would falsely indicate a wrong diagnosis of normal fertility before the testicular atrophy took place. In conclusion, in addition to the weight increase with age, the testicular atrophy and impairment of sperm production seemed to be the main reason to the decrease in the rooster's fertility at 50 weeks of age. Therefore, the use of the laparoscopy as a way to detect the roosters with testicular atrophy before 50 weeks of age and their removal from them flock could be useful as a diagnostic tool to prevent the birds’ fertility loss.  相似文献   

Can malignant and inflammatory pleural effusions in dogs be distinguished using computed tomography?          下载免费PDF全文

Thom C. Watton  Ana Lara‐Garcia  Christopher R. Lamb 《Veterinary radiology & ultrasound》2017,58(5):535-541

Computed tomography (CT) is the primary imaging modality used to investigate human patients with suspected malignant or inflammatory pleural effusion, but there is a lack of information about the clinical use of this test in dogs. To identify CT signs that could be used to distinguish pleural malignant neoplasia from pleuritis, a retrospective case‐control study was done based on dogs that had pleural effusion, pre‐ and postcontrast thoracic CT images, and cytological or histopathological diagnosis of malignant or inflammatory pleural effusion. There were 20 dogs with malignant pleural effusion (13 mesothelioma, 6 carcinoma; 1 lymphoma), and 32 dogs with pleuritis (18 pyothorax; 14 chylothorax). Compared to dogs with pleuritis, dogs with malignant pleural effusions were significantly older (median 8.5 years vs. 4.9 years, P = 0.001), more frequently had CT signs of pleural thickening (65% vs.34%, P = 0.05), tended to have thickening of the parietal pleura only (45% vs. 3%, P = 0.002) and had more marked pleural thickening (median 3 mm vs. 0 mm, P = 0.03). Computed tomography signs of thoracic wall invasion were observed only in dogs with malignant pleural effusions (P = 0.05). There were no significant differences in pleural fluid volume, distribution or attenuation, degree of pleural contrast accumulation, amount of pannus, or prevalence of mediastinal adenopathy. Although there was considerable overlap in findings in dogs with malignant pleural effusion and pleuritis, marked thickening affecting the parietal pleural alone and signs of thoracic wall invasion on CT support diagnosis of pleural malignant neoplasia, and may help prioritize further diagnostic testing.  相似文献