Gas chromatography-olfactometry and chemical quantitative study of the aroma of six premium quality spanish aged red wines   总被引：5，自引：0，他引：5  

Culleré L  Escudero A  Cacho J  Ferreira V 《Journal of agricultural and food chemistry》2004,52(6):1653-1660

The aroma of six premium quality Spanish red wines has been studied by quantitative gas chromatography-olfactometry (GC-O) and techniques of quantitative chemical analysis. The GC-O study revealed the presence of 85 aromatic notes in which 78 odorants were identified, two of which-1-nonen-3-one (temptatively) and 2-acetylpyrazine-are reported in wine for the first time. Forty out of the 82 quantified odorants may be present at concentrations above their odor threshold. The components with the greatest capacity to introduce differences between these wines are ethyl phenols produced by Brettanomyces yeasts (4-ethylphenol, 4-ethyl-2-methoxyphenol, and 4-propyl-2-methoxyphenol), 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol), (Z)-3-hexenol, thiols derived from cysteinic precursors (4-methyl-4-mercaptopentan-2-one, 3-mercaptohexyl acetate, and 3-mercaptohexanol), some components yielded by the wood [(E)-isoeugenol, 4-allyl-2-methoxyphenol, vanillin, 2-methoxyphenol (guaiacol), and (Z)-whiskylactone], and compounds related to the metabolism (2-phenylethanol, ethyl esters of isoacids, 3-methylbutyl acetate) or oxidative degradation of amino acids [phenylacetaldehyde and 4,5-dimethyl-3-hydroxy-2(5H)-furanone (sotolon)]. The correlation between the olfactometric intensities and the quantitative data is, in general, satisfactory if olfactometric differences between the samples are high. However, GC-O fails in detecting quantitative differences in those cases in which the olfactive intensity is very high or if odors elute in areas in which the odor chromatogram is too complex.  相似文献   

Aroma extract dilution analysis. Precision and optimal experimental design     

Ferreira V  Pet'ka J  Aznar M 《Journal of agricultural and food chemistry》2002,50(6):1508-1514

The odor thresholds of 12 different compounds have been determined in an AEDA experiment using a panel composed of 8 individuals. Only in one case is the distribution of thresholds among judges significantly different from the log-normal. The cause of that departure from normality seems to be a cross adaptation rather than anosmia. The standard deviations (SD) range from 2(0.7) to 2(4.1), with 2(1.8) as average. If the AEDA is carried out at a dilution rate, R, and dilution R(P) (where P = 0, 1, 2.) is the last one at which a compound was detected by a judge, the flavor dilution (FD) factor that should be provided for that judge is R(P+0.5). In the case where several judges carry out the AEDA, the FD for a given compound should be the geometric mean of the FD provided by all the judges. The SD of the distribution of FDs is related to that of the distribution of odor thresholds, but is strongly influenced by the dilution rate, R, being higher with higher R values. The relationship between both SDs can be used to determine the expected precision (measured as the geometric length of the 95% confidence interval) of the result of an AEDA experiment as a function of the dilution rate, the number of judges, and the SD of the distribution of thresholds. Different simulations have shown that in most cases, a dilution rate of 10 is the best option, and that lower dilution rates are advantageous only if the analyzed solution contains compounds with a very narrow distribution of thresholds.  相似文献   

Role of Azospirillum brasilense nitrate reductase in nitrate assimilation by wheat plants     

M. C. B. Ferreira  M. S. Fernandes  J. Döbereiner 《Biology and Fertility of Soils》1987,4(1-2):47-53

Summary The nitrogen metabolism of wheat plants inoculated with various Azospirillum brasilense strains and nitrate reductase negative (NR^–) mutants was studied in two monoxenic test tube experiments. The spontaneous mutants selected with chlorate under anaerobic conditions with nitrite as terminal electron acceptor fixed N₂ in the presence of 10 mM NO₃ ^– and were stable after the plant passage. One strain (Sp 245) isolated from surface-sterilized wheat roots produced significant increases in plant weight at both NO₃ levels (1 and 10 mM) which were not observed with the NR^– mutants or with the two other strains. Similar effects were observed in a pot experiment with soil on dry weight and total N incorporation but only at the higher N fertilizer level. In the monoxenic test tube experiments plants inoculated with the mutants showed lower nitrogenase activities than NR⁺ strains at the low NO₃ ^– level (1 = mM) but maintained the same level of activity with 10 mM NO₃ ^– where the activity of all NR⁺ strains was completely repressed. The nitrate reductase activity of roots increased with the inoculation of the homologous strains and with the mutants at both NO₃ ^– levels. At the low NO₃ ^– level this also resulted in increased activity in the shoots, but at the high NO₃ ^– level the two homologous strains produced significantly lower nitrate reductase activity in shoots while the mutants more than doubled it. The possible role of the bacterial nitrate reductase in NO₃ ^– assimilation by the wheat plant is discussed.  相似文献   

Identification of key odorants related to the typical aroma of oxidation-spoiled white wines   总被引：2，自引：0，他引：2  

Silva Ferreira AC  Hogg T  Guedes de Pinho P 《Journal of agricultural and food chemistry》2003,51(5):1377-1381

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Heavy metal and PCB spatial distribution pattern in sediments within an urban catchment—contribution of historical pollution sources     

Celia Dias-Ferreira  Rosinda L. Pato  Jorge B. Varejão  Alexandre O. Tavares  Antonio J. D. Ferreira 《Journal of Soils and Sediments》2016,16(11):2594-2605

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Effects of soil properties and humidity regimes on semi-natural meadow productivity     

Regina Skuodiene  Kazimieras Katutis  Rita Nekrosiene  Regina Repsiene  Danute Karcauskiene 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(8):653-663

ABSTRACT

The research has been conducted for four years in five phytocenoses affected by the processes of naturalization. Two of them are located in non-flooded, relatively abandoned meadows and the remaining - flooded meadows in different parts of the Nemunas delta (Western Lithuania). The aim of the research was to estimate the influence of ecological conditions (humidity regimes, soil agrochemical parameters) on semi-natural meadow productivity. Humidity regimes and nitrogen amount in the soil influenced dry matter (DM) yield of meadow phytocesosis. The biggest DM yield (8.64 ± 0.77 t ha^-1) was found in flooded meadow in the central part of the Nemunas delta in Terric Histosol (HSs) soil, which had moderate acidity and was rich in nitrogen. The economic value depended on the prevailing plant species and was the highest in non-flooded meadows. Botanical composition and plant species number depended on agrochemical characteristics of the soil and management activities: the greatest plant species diversity and the best plant population stability were established in flooded meadow in the riverside part of the Nemunas delta behind a levee in soil rich in phosphorus and potassium and low acidity. A similar number of plant species and similar ecological stability parameters were found in non-flooded meadow, whose soil was low in nutrients, but there was intensified farming.  相似文献   

Einsatz bakterieller Antagonisten zur Bekämpfung von Krankheiten verursacht durch Rhizoctonia solani     

Rita Grosch  Jana Lottmann  Franziska Faltin  Gabriele Berg 《Gesunde Pflanzen》2005,57(8):199-205

Rhizoctonia solani is an important soil-borne pathogen causing diseases in numerous economically important crops. The pathogen R. solani can be responsible for relevant yield losses as well as on lettuce and potato. To develop a biocontrol strategy, two bacterial strains, Pseudomonas fluorescens L13–6-12 and Serratia plymuthica 3Re4–18 were evaluated against R. solani causing black scurf in potato and bottom rot in lettuce. The disease suppression effect of the two antagonists was tested as well as in a climate chamber and in the field during two vegetation periods. The results of the climate chamber experiments showed, that R. solani can significantly reduced the lettuce growth. The dry mass losses on lettuce and the disease severity on potato sprouts were significantly limited through bacterization. The antagonist L13–6-12 showed best disease suppression effect in climate chamber experiments on both crops. A significant lower disease severity was to observed in treatments with bacterial antagonists as well as on lettuce plants and harvested potato tubers during both vegetation periods. Also the dry mass losses on lettuce were clear reduced in treatments with bacterial antagonists, whereas only a partly limitation of yield losses on potato was to achieved. In summary, the results supported that the use of bacterial antagonists can be part of a control strategy against R. solani.  相似文献   

Bronchopulmonary Disease in the Cat: Historical, Physical, Radiographic, Clinicopathologic, and Pulmonary Functional Evaluation of 24 Affected and 15 Healthy Cats   总被引：3，自引：0，他引：3  

Janice A. Dye  Brendan C. McKiernan DVM    Elizabeth A. Rozanski  Walter E. Hoffmann  John M. Losonsky  Linda D. Homco  Rita M. Weisiger  Ibulaimu Kakoma 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1996,10(6):385-400

The results of clinical and pulmonary functional evaluation of 24 cats with bronchopulmonary disease and 15 healthy cats are presented. Affected cats had historical evidence of excessive reflexes (coughing, sneezing); physical evidence of airway secretions (crackles), obstruction (wheezing), and increased tracheal sensitivity; radiographic evidence of bronchial and interstitial lung disease; and cytological evidence of airway inflammation or mucous secretions. Bacterial isolates from healthy and affected cats were predominantly Gram-negative rods, indicating that bronchi of cats are not always sterile and that normal flora should be considered in interpreting cultures from cats with suspected bronchopulmonary disease. Cats were grouped according to relative disease severity based on scored historical, physical, and radiographic abnormalities. The mean (± standard deviation) baseline lung resistance measurement in healthy cats was 28.9 cm H₂O/L/s (±6.2 cm H₂O/L/s), whereas in mildly, moderately, and severely affected cats it was 38.3 cm H₂O/L/s (±21.5 cm H₂O/L/s), 44.8 cmH₂O/L/s (±7.7 cm H₂O/L/s), and 105.2 cm H₂O/L/s (±66.9 cm H₂O/L/s), respectively. In healthy cats, dynamic lung compliance was 19.8 (±7.4), whereas in mildly, moderately, and severely affected cats it was 14.7 mL/cm H₂O (±3.8 mL/cm H₂O), 17.7 mL/cm H₂O (±6.9 mL/cm H₂O), and 13.0 mL/cm H₂O (±7.9 mL/cm H₂O), respectively. Thus, airway obstruction was present in many of the affected cats. Based on acute response to the bron-chodilator, terbutaline, airway obstruction was partially reversible in many affected cats, although the degree of reversibility varied. Furthermore, based on bronchoprovocation testing, 6 (of 7) affected cats evaluated also had increased airway responsiveness to aerosolized methacholine.  相似文献   

Detection of bovine herpesvirus 4 in CD11b+ leukocytes of experimentally infected rabbits     

Fábián K  Ivanics R  Terényi M  Egyed L 《Acta veterinaria Hungarica》2005,53(2):265-273

The presence and numbers of bovine herpesvirus 4 (BoHV-4) infected CD11b+ leukocytes were investigated during experimental infections of New Zealand White rabbits by Fluorescence Activated Cell Sorter (FACS) analysis. Peripheral blood leukocytes (PBL) were collected every second day, and the cells were stained with phycoerythrin-labelled CD11b-specific mouse monoclonal antibody and fluorescein-conjugated bovine herpesvirus 4-specific mouse monoclonal antibody. The numbers of double-stained cells from PBLs of the control and inoculated groups were measured and compared in FACSTREK analyser. Double-stained cells were detected in the virus-inoculated group on postinoculation days (PID) 2-5 and 9-12. The results indicated that CD11b+ PBLs were permissive for BoHV-4 infection, and are probably the main reservoir of the virus during the latent period. The data did not indicate production of infectious viral particles, but virus-specific proteins were expressed on the surface of CD11b+ cells. The two waves of double-stained cells gave similar results to the PCR assays from serum samples, which showed the presence of viral DNA in the serum on the same days when virus-infected CD11b cells were also present. Productive BoHV-4 infection of mast cells or undifferentiated leukocytes in the bone marrow and the antiviral immune response might be responsible for this periodic appearance of the virus in CD11b+ PBLs and in the serum. The paper provides evidence that CD11b+ PBLs are the main target cell populations in the blood for BoHV-4.  相似文献   

Molecular characterization and phylogenetic analysis of Newcastle disease virus isolates from healthy wild birds     

Zanetti F  Berinstein A  Pereda A  Taboga O  Carrillo E 《Avian diseases》2005,49(4):546-550

Wild waterfowl is considered a natural reservoir of potentially infectious agents and a source of pathogenic viruses like avian paramyxoviruses type 1 (APMV 1). In 1997, commercial poultry in Argentina had reached the status of being free from virulent Newcastle disease virus (NDV) infections. Vaccination and biosecurity measures are actively performed to maintain this preferential sanitary condition. However, the risk of reintroduction of pathogenic viruses is always present. In this context, we conducted a study to describe the status of wild healthy birds in a geographic region relevant for the poultry industry. The presence of anti-NDV antibodies was determined in different species in all areas sampled suggesting previous contact with NDV. Seven ND viruses were isolated and characterized as apathogenic strains by biological and molecular methods. The phylogenetic analysis revealed that the majority of the Argentinian isolates form a subgroup related to viruses of genotype II. The results presented here highlight the importance of maintaining strict biosecurity measures and vaccination programs in poultry industries in order to preserve the virulent NDV-free status for commercial flocks in the country.  相似文献