DISTRIBUTION OF GRISEOFULVIN TAKEN UP BY MICROSPORUM GYPSEUM: COMPLEXES OF THE ANTIBIOTIC WITH CELL CONSTITUENTS.

El-Nakeeb, Moustafa A. (Rutgers, The State University, New Brunswick, N.J.), and J. O. Lampen. Distribution of griseofulvin taken up by Microsporum gypseum: complexes of the antibiotic with cell constituents. J. Bacteriol. 89:1075-1081. 1965.-The griseofulvin-(4-methoxy-H(3)) accumulated by Microsporum gypseum was bound to fungal constituents. Mild procedures (hot-water or acetone extraction) removed between 40 and 60% of the total concentration of antibiotic. The remainder was recovered only after treatment with hot trichloroacetic acid followed by hot NaOH. The ratio of griseofulvin-H(3) in the water-soluble pool to that in the nucleic acid (soluble in hot trichloroacetic acid) and protein (soluble in NaOH) fractions was about 2:1:1, respectively. Only small amounts of radioactivity could be detected subsequent to hot-water extraction in the cold trichloroacetic acid extracts and in the cell-wall residues. Essentially all the activity in the soluble pool and in the nucleic acid extracts was chemically unchanged griseofulvin, much of which was present in various complexes, especially after long periods of incubation. One cannot be certain of the original form of all the radioactivity which was extracted in the protein fraction, because some degradation of the antibiotic occurred during the hot NaOH treatment. Nevertheless, a considerable amount of griseofulvin-H(3) was still present, and there had been no significant incorporation of radioactivity into the amino acid residues. It is probable, therefore, that the radioactivity in both protein and nucleic acid fractions represents complexes of the antibiotic with macromolecular components which were formed in vivo by the sensitive organisms.