Estandarización de un protocolo sencillo para la extracción de ADN genómico de levaduras / Standardising a simple protocol for extracting yeast from genomic DNA

Se estandarizó un protocolo rápido, sencillo y de bajo costo para la extracción de ADN genómico de levaduras a partir de lisis de la pared celular mediante tratamiento enzimático y precipitación por alcoholes. El empleo de la enzima Beta-glucoronidasa en reemplazo de la enzima Zimolasa, permitió obtener ADN en alta concentración (124,9±30,2 ng/λl) y de buena calidad (A260/A280 nm =1,86±0,1), ideal para su uso en estudios de biología molecular. Además, se adicionó un paso de incubación del ADN obtenido a 100° C para inactivar ADNasas. La calidad del ADN obtenido fue evaluada por medio de la amplificación de la región ITS1-5.8S-ITS2, presentando bandas definidas y cuantificables (entre 380 y 880 pb) ideales para estudios de identificación molecular y filogenia.

A quick, simple and low-cost protocol for extracting genomic DNA from yeast by cell wall lysis involving enzymatic treatment and alcoholic precipitation was standardised. Higher DNA yields (124.9±30.2 ng/λl) were obtained by using beta-glucuronidase instead of zymolyase; these had very high quality (A260/A280 nm = 1.86±0.1) and would be suitable for use in molecular biology assays. Moreover, a DNAse inactivation step was also introduced by incubation at 100 °C to further ensure DNA stability. DNA quality was assayed by PCR amplification of the ITS1-5.8S-ITS2 region, revealing defined, quantifiable 380 to 880 bp bands. These results show that the protocol is ideal for molecular identification and phylogenetic studies.

Thioglycollate-elicited murine macrophages are cytotoxic to Mycoplasma arginini-infected YAC-1 tumor cells

Macrophages are important components of natural immunity involved in inhibition of tumor growth and destruction of tumor cells. It is known that these cells can be activated for tumoricidal activity by lymphokines and bacterial products. We investigated whether YAC-1 tumor cells infected with Mycoplasma arginini stimulate nitric oxide (NO) release and macrophage cytotoxic activity. Thioglycollate-elicited macrophages from male BALB/c mice were co-cultured for 20 h with YAC-1 tumor cells infected or not with Mycoplasma arginini. The cytotoxic activity was evaluated by MTT assay and nitrite levels were determined with the Griess reagent. Thioglycollate-elicited macrophages co-cultured with noninfected YAC-1 cells showed low cytotoxic activity (34.7 ñ 8.6per cent) and low production of NO (4.7 ñ 3.1 µM NO2-). These macrophages co-cultured with mycoplasma-infected YAC-1 cells showed significantly higher cytotoxic activity (61.4 ñ 9.1 per cent; P=0.05) and higher NO production (48.5 ñ 13 µM NO2-; P=0.05). Addition of L-NAME (10 mM), an inhibitor of NO synthesis, to these co-cultures reduced the cytotoxic activity to 37.4 ñ 2per cent (P=0.05) and NO production to 3 ñ 4 µM NO2- (P=0.05). The present data show that Mycoplasma arginini is able to induce macrophage cytotoxic activity and that this activity is partially mediated by NO.