Sulphanilamides. Part II. In vitro synergism with anionic surface-active compounds

1. The bacteriostatic properties of sulphanilamide and five N1-substituted sulphanilamides, and of three anionic surface-active compounds, have been studied, singly and together, against the organisms, S. aureus, E. coli, and E. typhosa, using peptone-broth and a synthetic medium. 2. With incubation temperatures of 37° and 43° the concentration of sulphanilamide for bacteriostasis in peptone medium is independent of the age of the culture and the concentration of the inoculum at the higher temperature only. In the synthetic medium, the effects of age of cells and size of inocula are less pronounced at both temperatures of incubation. 3. The minimum effective concentrations of sulpha drugs needed for growth inhibition are more in peptone broth than in the synthetic medium. Similar but less pronounced differences are seen with the surface-active compounds against S. aureus. 4. While the surface-active compounds are by themselves ineffective against the Gram-negative organisms, they have potentiating activity with the sulpha drugs. 5. The synergic effects of sulphanilamide and surface-active compound are unaltered even when the organism is rendered resistant to sulphanilamide or when the antibacterial property of the surface-active compound is neutralized by lecithin

Polygalacturonase activity of Aspergilli

1. Three strains of Aspergilli having good PG activity were isolated. 2. The conditions for maximum elaboration of PG were studied using synthetic liquid media as well as wheat bran. (i) The enzyme content was maximum after 4 days of growth; pH below 5 favoured the formation of enzyme. (ii) Wheat bran was a better substrate than synthetic liquid media; aqueous glycerine was very satisfactory for extraction of the enzyme from wheat bran medium. 3. Partially purified PG preparations were obtained by precipitating enzyme at 60 per cent. concentration of ammonium sulphate after discarding the precipitate at 20 per cent. salt concentration; alcohol inactivated the enzyme to a great extent. 4. The optimum pH for activity with citrus pectin as substrate was about 4-5; hydrolysis was rapid during first 12-24 hours and decreased thereafter during a further 8-10 days period