Inactivation of phages DS6A and D29 by acetone extracts of Mycobacterium tuberculosis and Mycobacterium bovis.

The adsorption rate constant for mycobacteriophage DS6A on clumped cells of Mycobacterium tuberculosis strain H37Rv was found to be 6.33 x 10(-13) ml per min per colony former. Acetone-extracted cells of H37Rv did not absorb phage DS6A. Acetone extracts of cells of H37Rv and of Mycobacterium bovis strain BCG inhibited plaque formation of mycobacteriophage DS6A and of phage D29. Suspensions of these extracts in heart infusion broth with 0.002 M calcium chloride and 1 per cent dioxane required 20 hours of incubation (activation) at 37 degrees C with stirring before they were capable of inactivating phage DS6A, but did not require activation for inhibition of phage D29. Sonication of water mixtures of these extracts for 45 sec yielded suspensions that were highly active against phage DS6A and independent of the 20-hour lag period. Such preparations were also active against phage D29. The extract prepared from cells of BCG was more active than the extract from cells of H37Rv. Water washing of chloroform solutions of each extract did not remove significant amounts of solid material or reduce the phage-inactivating activites of either extract.