Showing papers by "Ministry of Agriculture published in 2002"

Immunoaffinity column clean-up and thin layer chromatography for determination of ochratoxin A in green coffee.

Abstract: An immunoaffinity clean-up-based method for determining ochratoxin A (OTA) in green coffee aiming at one-dimensional thin layer chromatography (TLC) analysis was established. OTA was extracted with a mixture of methanol and aqueous sodium hydrogen carbonate solution, purified through an immunoaffinity column, separated on normal or reversed-phase (RP) TLC plates and detected and quantified by visual and densitometric analysis. The linear equation of the standard calibration curve by densitometric analysis gave R(2) > 0.999 (0.04-84 ng). The mean recovery (R) of OTA from spiked samples (1.8-109 microg kg(-1)) by densitometric and visual analyses were 98.4 and 103.8%, respectively. The relative standard deviations (RSD) for densitometric and visual analysis varied from 1.1 to 24.9% and from 0.0 to 18.8%, respectively. The RSD for naturally contaminated samples by densitometry (three levels of contamination, n = 3) varied from 11.1 to 18.1%. The correlation (R(2)) between high-performance liquid chromatography (HPLC) and densitometry, and between visual and densitometric analysis for spiked samples were > 0.99. The limit of detection (LOD) of the method was 0.5 microg kg(-1) for normal TLC. Toluene-ethyl acetate-88% formic acid (6:3:1 v/v/v) and acetonitrile-methanol-water-glacial acetic acid (35:35:29:10 v/v/v/v) were regarded as the suitable TLC solvents for eluting both standards and samples on normal and RP TLC plates, respectively. Toluene-acetic acid (99:1 v/v) was chosen as the spotting solvent among several others for giving the best sensitivity and resolution of OTA on TLC plates as well as the best recovery of OTA from standard and sample extract residues. Preliminary studies were carried out to investigate the reuse of the immunoaffinity column and the interference of caffeine in the OTA recovery.

Preliminary survey for insects associated with Bursaphelenchus xylophilus in Portugal.

Abstract: The detection of Bursaphelenchus xylophilus in Pinus pinaster trees in Portugal in 1999 led the official services to implement exceptional and urgent control measures to prevent the spread of the pest. Because the pest is vector-transmitted, special attention was paid to the insects associated with infested trees. A survey comprising 21 species of insects, from six families, with a total of 1367 specimens, was made in order to evaluate their possible role as vectors of the nematode in Portugal. Five insect species were found to carry other Bursaphelenchus spp., but only Monochamus galloprovincialis was associated with B. xylophilus.

Avaliação do feno de Arachis pintoi utilizando o ensaio de digestibilidade in vivo

Abstract: Utilizaram-se seis ovinos, sem raca definida, para avaliar o consumo e as digestibilidades aparentes totais da materia seca (MS), materia orgânica (MO), proteina bruta (PB), extrato etereo (EE), carboidratos totais (CHO), fibra em detergente neutro (FDN), carboidratos nao fibrosos (CNF), fibra em detergente acido (FDA), celulose (CEL), hemicelulose (HCEL) e energia do feno de Arachis pintoi. Tambem foi determinado o balanco de nitrogenio. Os animais foram colocados em gaiolas metabolicas e receberam apenas o feno de A. pintoi mais sal mineral como componentes da dieta. O Arachis pintoi foi colhido com aproximadamente 100 dias. O fornecimento do feno foi ad libitum, sendo a quantidade calculada para permitir sobras de 20%. O experimento teve 20 dias de duracao, sendo 15 dias de adaptacao e cinco dias para coletas de amostras do feno, sobras, fezes e urina. Foi utilizado o oxido cromico, em duas doses diarias de 1 g cada, como indicador externo para estimar a producao fecal. Os consumos de MS e MO do A. pintoi foram 90,17 e 85,67 g/kg0,75, respectivamente. Os teores de PB, nutrientes digestiveis totais (NDT) e energia metabolizavel (EM) foram, respectivamente, 14,3%, 66,4% e 2,0 Mcal/kg MS. O balanco de nitrogenio (N) foi de 12,1 g/dia e representou 40,2% de todo N consumido. As digestibilidades aparentes totais da MS, MO, PB, EE, CHO, FDN, CNF, FDA, CEL, HCEL e energia foram 64,4, 68,4, 70,0, 63,4, 68,2, 53,6, 93,3, 47,2, 62,8, 66,8 e 63,7%, respectivamente. O feno de Arachis pintoi apresentou consumo e digestibilidades dos nutrientes elevados para uma forrageira, permitindo assim fornecer nutrientes em quantidades suficientes para ganhos de peso satisfatorios, o que da maior suporte para o uso dessa leguminosa na alimentacao de ruminantes.

Srebp pathway modulation through targeting hisrs

Abstract: Human HisRS genes are identified as modulators of the SREPB pathway and thus are therapeutic for disorders associated with the SREBP pathway. Methods for identifying modulators of HisRS, comprising screening for agents that modulate the activity of HisRS are provided.

Distribuição de anticorpos para herpesvírus bovino 1 em rebanhos bovinos

Abstract: A distribuicao de anticorpos neutralizantes para o herpesvirus bovino 1 (HVB 1) foi estudada em quatro faixas etarias de bovinos, em 21 rebanhos de leite e de corte. Os resultados da sorologia foram analisados e relacionados com as respostas de questionarios aplicados aos responsaveis pelos rebanhos. As taxas de frequencia de anticorpos neutralizantes para o HVB 1 foram comparadas segundo a aptidao e a faixa etaria. Fatores como tipo de manejo e idade dos animais influenciaram na distribuicao de anticorpos para o HVB 1.

Balanço de nitrogênio, degradabilidade de aminoácidos e concentração de ácidos graxos voláteis no rúmen de ovinos alimentados com feno de Stylosanthes guianensis

Abstract: - Seven sheep fed S. guianensis hay were used to evaluate ruminal amino acid degradability, nitrogen balance and rumenvolatile fatty acid (VFA) concentrations. Nylon bags technique was used for determination of the in situ degradabilities of amino acids.Bags were collected at 6, 24 and 48 hours after insertion. Duodenum and feces samples were used to determine amoniacal-N and no n-amoniacal-N. To determine ruminal VFA concentrations, samples of 80 mL were collected immediately before feeding and 2, 4, 6 an d8 hours after. Nitrogen balance was 6.0 g/day. S. guianensis had 10.4 and 6.3 g of methionine and lysine, respectively, per 100 g of totalamino acids. Non essential amino acids had degradation rates twice than essentials. Aminoacitic profile of undegradable protein wasdifferent than the original feed protein. The acetate:propionate ratio was 4.31. High concentrations of methionine and its low degradabilitymake the S. guianensis an important feed when this amino acid is limiting.Key Words: amino acid, degradability, hay, legume forages, sheep

Production and purification of epsilon prototoxin produced by Clostridium perfringens type D

Abstract: A prototoxina epsilon foi obtida a partir de cultivo liquido, rico em carboidratos, a partir de amostra de C. perfringens tipo D (INTA - Argentina), incubado em condicoes de anarobiose a 37oC por oito horas. O sobrenadante da cultura foi concentrado utilizando-se o sistema Amicon com membrana de "cut off" de 10 kDa. O concentrado foi precipitado com sulfato de amonio (350 g/ml) e dissolvido em tampao fosfato 0,01 M (pH 7,2). A prototoxina purificada por cromatografia de troca ionica (DEAE-Sepharose CL 6B) e isolada no primeiro pico, mostrou uma banda unica de aproximadamente 34kDa de peso molecular em SDS-PAGE, alem de ser toxica em camundongos.

Surface Fluorination of Carboxylated Nitrile Butadiene Rubber: An XPS Study

Abstract: Because of their exceptional reactivity, fluorine and fluorinated gases are of primary importance for the modification of the surface properties of materials. This study is devoted to surface treatment of thin nitrile gloves, made of carboxylated nitrile butadiene rubber latex, using either direct fluorination (10% F2gas diluted in N2) or plasma-enhanced fluorination in radio-frequency cold plasmas using fluorinated gases (CF4, CHF3). Mechanisms of fluorination of these co-elastomers have been proposed on the basis of the assignment of the different components of the XPS spectra. Several mechanisms have been observed depending on the fluorination conditions. Although the modification of nitrile gloves is already effective for fluorination reactions at room temperature, an important activation is observed for experiments carried out at 90°C. When the treatments are carried out at room temperature, a gradual fluorination occurs: in the case of 10% diluted F2 gas, monofluorinated C—F groups are the species most found at the surface and perfluoro groups CFn are present in lower amount. An addition reaction takes place at the \(\rlap{--} (\)CH=CH\(\rlap{--} )\) double bonds of the polybutadiene entities, leading to \(\rlap{--} (\)CHF=CHF\(\rlap{--} )\) units. Whatever the fluorination method, thermal activation yields a more massive fluorination of the surface that finally leads to perfluorinated \(\rlap{--} (\)CF2\(\rlap{--} )\) groups and terminal —CF3 groups.

Avaliação da estabilidade in vitro de uma protease comercial

Abstract: This work aimed to evaluate the in vitro activity of a commercial protease (VEGPROâ ). The enzyme was incubated at 80oC during 0, 0.5, 1, 5, 10 and 15 minutes. The gastric acidity effect was evaluated in the following treatments: pH 5.0 and pH 2.3 without pepsin and pH 2.3 with pepsin. The enzyme was incubated in calcium, copper, cobalt, manganese, magnesium and iron solutions to evaluate the effects of metalic ions. The activity of the commercial protease was maintained in all in vitro conditions tested.