A new disruption vector (pDHO) to obtain heterothallic strains from both Saccharomy cescerevisiae and Saccharomyces pastorianus

Yeasts are responsible for several traits in fermented beverages, including wine and beer, and their genetic manipulation is often necessary to improve the quality of the fermentation product. Improvement of wild-type strains of Saccharomyces cerevisiae and Saccharomyces pastorianus is difficult due to their homothallic character and variable ploidy level. Homothallism is determined by the HO gene in S. cerevisiae and the Sc-HO gene in S. pastorianus. In this work, we describe the construction of an HO disruption vector (pDHO) containing an HO disruption cassette and discuss its use in generating heterothallic yeast strains from homothallic Saccharomyces species (AU)

No disponible

Efecto antitumoral del gen suicida HSV-tk y ganciclovir en un modelo experimental de carcinoma epidermoide de cabeza y cuello / Antitumoral effect of HSV-tk suicide gene associated with ganciclovir in an experimental model of head and neck squamous cell carcinoma

Introducción: Se estudió la transfección por adenovectores y el efecto antitumoral del gen HVS-tk asociado a ganciclovir (AdCMVtk/GCV) en células KB de carcinoma epidermoide oral humano, in vitro e in vivo. Material y métodos: La trasfección por adenovectores se comprobó al teñir con X-gal cultivos y cortes tumorales KB tras exponerlos al adenovector AdCMVlacZ. El efecto antitumoral de AdCMVtk/GCV in vitro se estudió al comparar la supervivencia entre cultivos expuestos a AdCMVtk/GCV y a AdCMVlacZ/GCV. Para valorar el efecto antitumoral in vivo, se comparó el volumen de necrosis tumoral con respecto al total, entre animales tratados con AdCMVtk/GCV y con AdCMVlacZ/GCV. Se estudió la toxicidad hepática y renal. Resultados: In vitro, la supervivencia con AdCMVtk/GCV es menor que con AdCMVlacZ/GCV. In vivo, el volumen de necrosis es mayor con AdCMVtk/GCV que con AdCMVlacZ/GCV. No se constató toxicidad hepática ni renal. Conclusiones: Las células KB se transfectan por adenovectores y son destruidas por AdCMVtk/GCV, in vitro e in vivo (sin toxicidad en este modelo experimental animal) (AU)

INTRODUCTION: We studied the transfection by adenoviral vectors and the antitumoral effect of HSV-tk gene associated with ganciclovir (AdCMVtk/GCV) in KB human oral cavity squamous cell carcinoma, in vitro and in vivo. MATERIALS AND METHODS: Transfection was assessed by the X-gal stain. It was used in cell cultures and tumoral sections previously exposed to adenoviral vector AdCMVlacZ. In vitro, in order to study the antitumoral effect of AdCMVtk/GCV, survival of cell cultures exposed to AdCMVtk/GCV and to AdCMVlacZ/GCV was compared. In vivo, necrotic volume as a percentage of total tumoral volume, was compared between AdCMVtk/GCV treated group and AdCMVlacZ/GCV exposed group. Hepatic and renal toxicities were assessed. RESULTS: In vitro, survival of cell cultures treated with AdCMVtk/GCV was less than AdCMVlacZ/GCV exposed cells. In vivo, necrotic volume was larger in AdCMVtk/GCV treated group than in AdCMVlacZ/GCV exposed group. No toxicity was found (hepatic, renal). CONCLUSIONS: KB cells are transfected by adenoviral vectors and are killed by AdCMVtk/GCV, both in vitro and in vivo (no toxicity was found in the animal model) (AU)