5 Matching Annotations
  1. May 2019
    1. Selected transformants were grown in 250 ml of LBamp 0/N. The cells from the 0/N cultures were harvested by centrifugation (4°C) at 4000 X g for 30 min. The cell pellet was resuspended in 5 ml of TEG solution containing lysozyme (2.0 mg/ml in 10 mM Tris-HCl, pH 8.0) and incubated at RT for 15 min. Alkaline-SDS (10 ml) was added to the mixture and again incubated at R T for 10 min after mixing the contents gently by inverting the tube. Post-incubation, chilled sodium acetate solution (7.5 ml) was added and the contents were incubated on ice for 15 min. After incubation, the mixture was centrifuged at 10,000 X g at 4°C and processed in the similar fashion as described above upto addition of isopropanol. The DNA pellet was resuspended in 500 Jll TE containing 20 Jlg/ml RNase and incubated for 1 h at 37°C. Plasmid DNA was then extracted as described above. The DNA pellet was air-dried and finally dissolved in 200 Jll ofTE
    2. Large scale plasmid DNA isolation
    1. The reaction mixture contained 10 μl of culture filtrate, 490 μl of double distilled water (DDW) and 300 μl of methanolic rhodanine solution. This mixture was incubated for 5 min at 30°C in a water bath. The reaction was stopped by adding 0.3 ml of methanolic rhodanine solution (0.667 %), which resulted in the formation of complex between gallate and rhodanine. This was followed by the addition of 0.2 ml of KOH solution (0.5N) and the tubes were further incubated at 30°C for 5 min. The total reaction mixture in each tube was diluted with 4.0 ml of distilled water. Tubes were further incubated at 30°C for 10 min. The absorbance was measured at 520 nm against a control having distilled water in place of culture filtrate. The absorbance thus obtained was used to calculate the amount of gallic acid present in the culture filtrate, from the standard gallic acid curve prepared in the range of 100-1000 μg/ml.
    2. The procedure of Sharma et al. (2000) was used to estimate the gallic acid in the culture filtrate. Reagents: Methanolic rhodanine solution (0.667% w/v): Prepared by dissolving 0.667 g of rhodanine in 100 ml of methanol.Potassium hydroxide (0.5 N): 2.8 gpotassium hydroxide dissolved in100 ml of distilled water.
    3. Gallic acid estimation (Sharma et al., 2000)