MODE OF ACTION OF XANTHOCILLIN X MONOMETHYLETHER ON MULTIPLICATION OF NEWCASTLE DISEASE VIRUS IN CULTURED CELLS - (STUDIES ON ANTIVIRAL AND ANTITUMOR ANTIBIOTICS .15.)

The mechanism of the action of xanthocillin X monomethylether (XME) on multiplication of Newcastle disease virus (NDV) in cultured cells was studied. The inhibitory effect of XME was exerted whenever the antibiotic (15μg/ml) was added during the viral one-step growth cycle, and the effect could be reversed after removal of the antibiotic by washing. A lag period of approximately 5 hours was observed before the restoration of hemagglutinin synthesis had occurred. Pretreatment of host cells with XME for 7 hours and subsequent removal of the antibiotic did not affect velocity and yield of virus production. XME completely inhibited protein synthesis in both virus infected and mock-infected cells, however total actinomycin D-insensitive RNA synthesis was found to be practically the same in antibiotic-treated cells as in the control. Actinomycin D-insensitive RNA synthesized in the presence of XME was more heterogeneous than the control using methylated albumin-kieselguhr (MAK) column chromatography. Antiviral activity of XME was compared with that of other antibiotics known to be inhibitors of protein synthesis. XME was found to be one of the best inhibitors among all compounds tested, due to its low cytotoxicity and low effective concentration in agar-diffusion plaque-inhibition tests. © 1969, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.