The production, isolation, chemical and physical characteristics and biological properties of the new antiviral antibiotics, xanthocillin X mono- and dimethylether, and methoxy-xanthocillin X dimethylether are described. They were produced by two strains of Aspergillus sp. isolated from soil samples. The active principles were extracted from the mycelium, and isolated as yellowish crystals. They were identified as derivatives of xanthocillin X by physical methods. All three were effective against Newcastle disease, vaccinia and herpes simplex viruses in plate assays, and all inhibited the growth of Bacillus subtilis.
Effects of XME, XDE and XTE (xanthocillin X mono- and dimethylether, and methoxy-xanthocillin X dimethylether) on multiplication of Newcastle disease virus (NDV) and on proliferation of chick embryo fibroblast cells (CEF) were examined. At low multiplicity, XME, XDE and XTE suppressed CPE at low concentrations. At high multiplicity, XME (10 mcg/ml) completely inhibited occurrence of CPE and syntheses of HA and infective virus, and at lower concentrations there was no difference in final yields of HA at 23 hours post infection, but a concentration dependency was found in synthesis of HA and suppression of CPE. XDE and XTE, on the other hand, did not inhibit HA synthesis completely at high concentration, but delayed the onset of HA production and partially arrested the occurrence of CPE post infection. All three antibiotics had very low toxicity against both grown and growing primary CEF. They also had no effect on free NDV particle and on viral adsorption onto CEF.
A new antibiotic, tuberactinomycin, has been isolated from fermentation broth of a streptomyces named Streptomyces griseoverticillatus var. tubei'acticus.Tuberactinomycin is a water-soluble antibiotic belonging to the basic peptide antibiotic group, and markedly stable in acid or neutral solution. Tuberactinomycin is recovered from fermentation broth by means of a cation exchange resin process. Tuberactinomycin shows low toxicity and the activity against pathogenic tubercular bacilli both in vitro and in vivo. Taxonomical study of the producing strain, the isolation and properties of the antibiotic are reported in this paper.