Evaluation of the effects of animal age, concurrent bacterial infection, and pathogenicity of porcine reproductive and respiratory syndrome virus on virus concentration in pigs     

Cho JG  Dee SA  Deen J  Guedes A  Trincado C  Fano E  Jiang Y  Faaberg K  Collins JE  Murtaugh MP  Joo HS 《American journal of veterinary research》2006,67(3):489-493

OBJECTIVE: To evaluate the influences of animal age, bacterial coinfection, and porcine reproductive and respiratory syndrome virus (PRRSV) isolate pathogenicity on virus concentration in pigs. ANIMALS: Twenty-one 2-month-old pigs and eighteen 6-month-old pigs. PROCEDURE: Pigs were grouped according to age and infected with mildly virulent or virulent isolates of PRRSV. The role of concurrent bacterial infection was assessed by infecting selected pigs with Mycoplasma hyopneumoniae 21 days prior to inoculation with PRRSV. On alternating days, blood and swab specimens of nasal secretions and oropharyngeal secretions were collected. On day 21 after inoculation with PRRSV, selected tissues were harvested. Concentrations of PRRSV were determined by use of quantitative real-time PCR and expressed in units of TCID(50) per milliliter (sera and swab specimens) or TCID(50) per gram (tissue specimens). RESULTS: Concentrations of virus were higher in blood and tonsils of pigs infected with virulent PRRSV. Pigs infected with virulent PRRSV and M hyopneumoniae had significantly higher concentrations of viral RNA in lymphoid and tonsillar tissue. Coinfection with M hyopneumoniae resulted in a higher viral load in oropharyngeal swab specimens and blood samples, independent of virulence of the PRRSV isolate. Two-month-old pigs had significantly higher viral loads in lymph nodes, lungs, and tracheal swab specimens than did 6-month-old pigs, independent of virulence of the PRRSV isolate. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple factors affect PRRSV concentration in pigs, including pathogenicity of the PRRSV isolate, age, and concurrent infection with M hyopneumoniae.  相似文献   

Resistance to oxidation of white wines assessed by voltammetric means     

Rodrigues A  Silva Ferreira AC  Guedes de Pinho P  Bento F  Geraldo D 《Journal of agricultural and food chemistry》2007,55(26):10557-10562

This work concerns the development of a methodology suited to measure the resistance to oxidation of white wines by cyclic voltammetry. The voltammetric responses of several white wines of different origin and age were analyzed in the oxidation potential range (0.2-1.2 V vs SCE). Currents measured at fixed potentials were correlated to the concentration of ascorbic acid, SO2, and total phenolics. A forced degradation study was monitored by cyclic voltammetry; from plots of current versus time, the consumption rates of oxidizable species in wine were estimated.  相似文献   

Further insights into the role of methional and phenylacetaldehyde in lager beer flavor stability   总被引：2，自引：0，他引：2  

Soares da Costa M  Gonçalves C  Ferreira A  Ibsen C  Guedes de Pinho P  Silva Ferreira AC 《Journal of agricultural and food chemistry》2004,52(26):7911-7917

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Evaluation of some carotenoids in grapes by reversed- and normal-phase liquid chromatography: a qualitative analysis     

Mendes-Pinto MM  Ferreira AC  Oliveira MB  Guedes de Pinho P 《Journal of agricultural and food chemistry》2004,52(10):3182-3188

Carotenoids in grapes of three Port winemaking cultivars were investigated. Extracts were obtained with n-hexane/diethyl ether mixtures (0/100; 20/80; 50/50; 100/0) and analyzed by normal and reversed phase HPLC-DAD. Selection and identification of peaks were based on spectroscopic characteristics - lambda(max), (%III/II) and k' values, leading to 28 probable carotenoids. Using pure standards, it was possible to identify seven compounds previously described (neochrome, neoxanthin, violaxanthin, flavoxanthin, zeaxanthin, lutein, and beta-carotene), one more type of neochrome reported here, for the first time, and in addition, two geometrical isomers of lutein and beta-carotene were tentatively described. The remaining 17 need to be further identified. High polarity solvent mixtures lead to qualitatively richer chromatograms. Reversed-phase separations allowed the detection of flavoxanthin and the possible geometrical isomer(s) of beta-carotene. Under normal phase, zeaxanthin was detected, and neochromes were better separated from neoxanthin. Extraction with 50/50 n-hexane/diethyl ether mixtures and reversed-phase conditions was the best combination for analysis of the carotenoids, known as precursors of compounds with high aroma impact in wines.  相似文献   

Kinetics of oxidative degradation of white wines and how they are affected by selected technological parameters     

Ferreira AC  de Pinho PG  Rodrigues P  Hogg T 《Journal of agricultural and food chemistry》2002,50(21):5919-5924

The negative effects of oxygen on white wine quality and the various factors which influence it (including temperature, dissolved oxygen, pH, and free SO(2)) are well documented both at the sensory and compositional levels. What is less defined is the quantitative relationship between these parameters and the kinetics of the development of the negative effects of oxidation. The experiment presented here attempts to generate data which can be used to predictively model the oxidative degradation of white wines. Bottled wines were submitted to extreme conditions (45 degrees C temperature, O(2) saturation) during 3 months witth samples taken every 15 days for both sensorial and chemical analysis (GC-O/FPD/MS, 420 nm). The synergistic effects of increasing temperature and O(2) at lower pH are evident, both on the decrease in levels of terpene alcohols and norisoprenoids (which impart floral aromas), and on the development of off-flavors such as "honey-like", "boiled-potato", and "farm-feed" associated with the presence of phenylacetaldehyde, methional, and 1,1,6-trimethyl-1,2-dihydronaphthalene.  相似文献   

Determination of carotenoid profiles in grapes, musts, and fortified wines from Douro varieties of Vitis vinifera.     

P Guedes De Pinho  A C Silva Ferreira  M Mendes Pinto  J G Benitez  T A Hogg 《Journal of agricultural and food chemistry》2001,49(11):5484-5488

beta-Carotene and six xanthophylls (lutein, neoxanthin, violaxanthin, luteoxanthin, cryptoxanthin, and echinenone) have been identified and semiquantitatively or quantitatively determined in musts and port wines for the first time. An HPLC method was developed and compared with that of one based on thin layer cromatography with scanning densitometry. The most abundant carotenoids present in red grape varieties are beta-carotene and lutein. In wines, significant quantities of violaxanthin, luteoxanthin, and neoxanthin were found. This study was done with berries (skin and pulp), musts, and fortified wines. Some experiments were performed to follow carotenoid content from grapes to wines. Although the levels of beta-carotene and lutein found in fortified wines were lower than those found in musts, other xanthophylls, such as neoxanthin, violaxanthin, and luteoxanthin, exist in appreciable amounts in young ports.  相似文献   

A comparative study of an indirect fluorescent antibody test and an immunoperoxidase monolayer assay for the diagnosis of porcine proliferative enteropathy.     

Roberto M C Guedes  Connie J Gebhart  Nathan L Winkelman  Rebecca A Mackie-Nuss 《Journal of veterinary diagnostic investigation》2002,14(5):420-423

The currently used indirect fluorescent antibody test (IFAT) for the detection of antibodies against porcine proliferative enteropathy (PPE) was compared to an immunoperoxidase monolayer assay (IPMA). Serum samples used in this comparison were collected from 5-week-old pigs on day 0 (pre-experimental challenge) and on days 7, 14, 21, and 28 after oral inoculation with intestinal homogenate from pigs affected by PPE (28 challenged pigs) and sucrose phosphate glutamate solution (2 control pigs). All animals were euthanized 4 weeks after inoculation. Immunohistochemistry staining was applied to formalin-fixed, paraffin-embedded sections of ileum for the detection of Lawsonia intracellularis antigen. The serology results with each method agreed in all samples, except on days 0 and 7 in 1 control animal, which was positive by IPMA, but negative by IFAT. The percentage of agreement between IFAT and IPMA was 98.6%.  相似文献   

Area-wide survey of thiamethoxam resistance and control failure likelihood in the rice stink bugs Oebalus poecilus and O. ypsilongriseus     

Vieira  J. L.  Campos  S. O.  Smagghe  G.  Fragoso  D. B.  Barrigossi  J. A. F.  Guedes  R. N. C. 《Journal of pest science》2022,95(3):1151-1161

Journal of Pest Science - Insecticide resistance survey is an in-situ biomonitoring method to assess potential impact of pesticides that exhibit direct economic consequences when leading to control...  相似文献   

Detection of rabies virus antigen by the indirect rapid immunohistochemistry test in equines and comparisons with other diagnostic techniques     

Ranieli B. C. Torquato  Keila Iamamoto  Elaine R. Fernandes  Samira Achkar  Sandriana R. Silva  Iana S. S. Katz  Fernanda Guedes 《Zoonoses and public health》2020,67(6):651-657

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Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae     

A. Catarina Guedes  Maria S. Gi?o  Rui Seabra  A. C. Silva Ferreira  Paula Tamagnini  Pedro Moradas-Ferreira  F. Xavier Malcata 《Marine drugs》2013,11(4):1256-1270

A growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae) and 23 species of (eukaryotic) microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-soluble antioxidants, was evaluated by the (radical cation) ABTS method. For complementary characterization of cell extracts, a deoxyribose assay was carried out, as well as a bacteriophage P22/Salmonella-mediated approach. The microalga Scenedesmus obliquus strain M2-1 exhibited the highest (p > 0.05) total antioxidant capacity (149 ± 47 AAU) of intracellular extracts. Its scavenger activity correlated well with its protective effects against DNA oxidative damage induced by copper(II)-ascorbic acid; and against decay in bacteriophage infection capacity induced by H₂O₂. Finally, performance of an Ames test revealed no mutagenic effects of the said extract.  相似文献