Bennett, E. O.2022-02-082022-02-08196617972051https://hdl.handle.net/10657/8673Bacto agar reversed the effect of basic antibiotics while acidic and amphoteric antibiotic were not markedly affected. The reversal of activity was shown to be due to the presence of a diffusable, non-dialyzable sulfated polyanionic carbohydrate. This substance was shown to bind cationic dyes and form insoluble complexes with some basic antibiotics. Antibiotic activity was not markedly affected by the pore size of the agar or by the presence of diffusable, physiologically active substances in the agar. Such of the antagonism of Bacto agar was removed by precipitation of the agar with ethanol or by extraction of polymerized agar with ammonium hydroxide. It is possible that the ammonium hydroxide extraction may be commercially feasible and will yield an agar product suitable for the evaluation of antibiotic activity.application/pdfenThis item is protected by copyright but is made available here under a claim of fair use (17 U.S.C. §107) for non-profit research and educational purposes. Users of this work assume the responsibility for determining copyright status prior to reusing, publishing, or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires express permission of the copyright holder.Thesisreformatted digital