Método eletroforético rápido para detecção da adulteração do leite caprino com leite bovino / Fast electrophoretic detection method of adulteration of caprine milk by bovine milk

Avaliaram-se os métodos de eletroforese em gel de poliacrilamida (PAGE) em presença de uréia (uréia-PAGE) e dodecil sulfato de sódio (SDS-PAGE) para identificar a adulteração do leite de cabra pela adição do leite de vaca. Um método foi otimizado para preparação do caseinato de sódio em poucos minutos para análise eletroforética. Uréia-PAGE foi o método mais apropriado para identificação desse tipo de fraude, em decorrência da presença da caseína alfas1 com migração mais rápida no leite bovino. A presença da alfas1-caseína bovina foi detectada a partir da adição de 2,5 por cento de leite de vaca utilizando uréia-PAGE. O limite de detecção, a repetibilidade, o tempo para execução indicaram que esse método pode ser aplicado como rotina no controle de qualidade do leite de cabra recebido pelas indústrias de processamento.

Polyacrylamide gel electrophoresis (PAGE) in presence of urea (urea-PAGE) or sodium dodecyl sulfate (SDS-PAGE) was evaluated to detect the presence of cow milk added to goat milk. A method was optimized to prepare sodium caseinate from milk in few minutes. After that, the sodium caseinate was analyzed by PAGE. The urea-PAGE was the most appropriated method to identify adulteration as caprine and bovine alphas1-caseins displayed different migration rates. When cow milk was added to goat milk at different proportions, the presence of bovine alphas1-casein was detected in the mixture by urea-PAGE for a minimal proportion of 2.5 percent of cow milk added to goat milk. The good sensitivity, the repeatability and the short time for execution indicate that the described method will be able to be routinely applied for the quality control of goat milk in dairy industry.

Immunological properties of gene vaccines delivered by different routes

Gene vaccines represent a new and promising approach to control infectious diseases, inducing a protective immune response in the appropriate host. Several routes and methods of genetic immunization have been shown to induce antibody production as well as T helper (Th) cell and cytotoxic T lymphocyte activation. However, few studies have compared the nature of the immune responses generated by different gene vaccination delivery systems. In the present study we reviewed some aspects of immunity induced by gene immunization and compared the immune responses produced by intramuscular (im) DNA injection to gene gun-mediated DNA transfer into the skin of BALB/c mice. Using a reporter gene coding for ß-galactosidase, we have demonstrated that im injection raised a predominantly Th1 response with mostly IgG2a anti-ßgal produced, while gene gun immunization induced a mixed Th1/Th2 profile with a balanced production of IgG2a and IgG1 subclasses. Distinct types of immune responses were generated by different methods of gene delivery. These findings have important implications for genetic vaccine design. Firstly, a combination between these two systems may create optimal conditions for the induction of a broad-based immune response. Alternatively, a particular gene vaccine delivery method might be used according to the immune response required for host protection. Here, we describe the characteristics of the immune response induced by gene vaccination and the properties of DNA involved in this process