RESUMO
Foreign genes were introduced and expressed in vivo in guinea pigs and cattle utilizing a new hand-held device based on high-pressure helium gas to accelerate DNA-coated microparticles. Guinea pigs were used to evaluate the physical parameters to introduce and express the exogenous DNA. The best conditions were applied to conduct bombardments in cattle. The results showed a high frequency of gene expression in all the bombarded cattle. This procedure could be used to study the immune responses in cattle and in a wide variety of animals through genetic immunization.
Assuntos
Biolística , Expressão Gênica/genética , Animais , Bovinos , Cobaias , Imunização , beta-Galactosidase/genéticaRESUMO
Foreign genes were introduced and expressed in vivo in guinea pigs and cattle utilizing a new hand-held device based on high-pressure helium gas to accelerate DNA-coated microparticles. Guinea pigs were used to evaluate the physical parameters to introduce and express the exogenous DNA. The best conditions were applied to conduct bombardments in cattle. The results showed a high frequency of gene expression in all the bombarded cattle. This procedure could be used to study the immune responses in cattle and in a wide variety of animals through genetic immunization.
Assuntos
Cobaias , Bovinos , Animais , beta-Galactosidase/genética , Biolística/estatística & dados numéricos , Expressão Gênica/genética , ImunizaçãoRESUMO
Different cell cycle synchronization methods were used to increase the mitotic index and accuracy of sex determination in murine and bovine embryos. For sexing purposes, colchicine treatment for 2, 4, 6 and 8 h and the FdU-thymidine-colchicine combination were tested in murine embryos. The best results were obtained with colchicine treatment for 8 h (96.88% accuracy) and with FdU-thymidine-colchicine (97.22% accuracy). Mitotic indexes differed significantly between the 2 treatments (21.71% for colchicine and 32.95% for FdU-thymidine-colchicine). For sex identification of murine and bovine demi-embryos, both treatments were demonstrated to be equally effective (nearly 90%). The mitotic index for the FdU-treated murine demi-embryos (19.04%) was higher than the one obtained for the 8-h colchicine treatment (15.62%).