RESUMO
Ochratoxin A (OTA) is a mycotoxin contaminating agricultural products produced by fungi, associated with important toxic effects. Thus, the development of fast, sensitive, and economical approaches for OTA detection is crucial. In this study, a barcode-style lateral flow assay for the semi-quantitative detection of OTA in coffee samples was developed. To achieve this goal, a BSA-OTA complex was immobilized in three test zones to compete with OTA molecules in the sample for binding with anti-OTA antibodies labeled with gold nanoparticles. Different concentrations of OTA in the sample produced distinct colour patterns, allowing semi-quantification of the analyte. The assay exhibited high sensitivity, with a limit of detection of 2.5 µg.L-1, and high reproducibility, with variation coefficient values between 2% and 13%. Moreover, the colour patterns obtained in the analysis with coffee samples were similar to the results obtained with standard OTA solutions, demonstrating a reliable applicability in real samples.
Assuntos
Nanopartículas Metálicas , Ocratoxinas , Café/química , Ouro/química , Reprodutibilidade dos Testes , Contaminação de Alimentos/análise , Nanopartículas Metálicas/química , Ocratoxinas/análiseRESUMO
Canine distemper is a contagious, incurable, often fatal, multisystemic viral disease that affects the respiratory, gastrointestinal, and central nervous systems. Distemper is caused by the canine distemper virus (CDV). The development of antibodies to use in therapy and diagnosis is essential for the control of some diseases. Immunization of chickens with CDV results in the production of antibodies specific. However, there is relatively limited information available concerning immune response of CDV in this species. In the present study, immune responses were examined in serum and egg yolk from laying hens injected with CDV. The results demonstrated that the increase of antibody activity occurs first in the serum, and then in egg yolk with a lag in time of 1 to 3 week in the chickens. However, the time of elevated levels of antibody activity was much shorter in serum than the egg yolk.
Assuntos
Ensaio de Imunoadsorção Enzimática , Anticorpos , Vírus da Cinomose CaninaRESUMO
Canine parvovirus (CPV), cause an intestinal disease characterized by bloody diarrhea, is often fatal in puppies. The virus is transmitted by contact with infected dogs or their feces. The virus is very stable in the environment and may survive for several months in contaminated areas. The CPV attacks the rapidly diving cells of the bone marrow and the small intestine. Several laboratory tests have been developed and are available for specific viral diagnosis. Where facilities are available, rapid diagnosis can be made by electron microscopy (EM) of fecal material from cases with typical signs of disease. The virus also can be isolated in several feline and canine cell lines such as canine and feline kidney cells, but isolation is seldom used in practice since cell cultures are required and at least 1 week for results is required. Fecal hemagglutination-hemagglutination (HA-HI) tests have provided a simple and rapid method for detecting virus in fecal and tissue samples and are employed by several diagnostic laboratories, however the HA test is less sensitive than EM or enzyme-linked immunoassays (ELISA). In this work, the laying chickens are immunized with the canine parvovirus strain Cornell 780916-80 and the egg yolk antibody (IgY) isolated and characterized by indirect ELISA to detect canine parvovirus in feces.