In the course of a screening program, a novel quinolone antibiotic, YM-30059 (Fig. 1) was isolated from the culture broth of Arthrobacter sp. YL-02729S. YM-30059 exhibited relatively high antibacterial activities against Gram-positive bacteria including multiple-drug resistant Staphylococcus aureus and S. epidermidis. The present paper deals with the taxonomy of the producing organism, fermentation, isolation, structure elucidation and biological activity of the new antibiotic.

Okilactomycin, a novel antibiotic, was isolated from the culture filtrate of a strain of actinomycetes. The producing organism, strain YP-02908L, was identified as Streptomyces griseoflavus subsp. zamamiensis subsp. nov. The antibiotic was extracted with ethyl acetate and purified by silica gel column chromatography. It was obtained as colorless prisms from a dichloromethane solution. It exhibited weak antimicrobial activity against Grampositive organisms in vitro. It also exhibited antitumor activity against Ehrlich ascites carcinoma in vivo. The apparent molecular formula of okilactomycin was determined as C24H32O6.It is a new memberof the lactone group antibiotics. 1475 In the course of our screening for new antibiotics, a novel antibiotic, okilactomycin, was found. The antibiotic was produced by Streptomyces griseoflavus subsp. zamamiensis subsp. nov. It exhibited weak antimicrobial activity against Gram-positive organisms and antitumor activity agaist Ehrlich ascites carcinoma. In this paper, we describe the taxonomy of the producing organism, the fermentation, isolation and characterization of the antibiotic. Materials and Methods Chemicals Chemicals employed were as follows: Kieselgel 60 and TLC plates Silica gel 60 F254 (0.25 mm thickness) from E. Merck, Darmstadt, FRG; Sephadex LH-20 from Pharmacia Fine Chemicals, Sweden; mitomycin C from KyowaHakko Kogyo Co., Ltd., Japan. All other chemicals were of analytical grade. Components for Media Components for media employed were as follows :

A new antibacterial antibiotic tetrazomine was found from the fermentation broth of an actinomycete strain which was isolated from beach sand collected at Chichijima, Ogasawara Islands, Tokyo, Japan. The strain Y-09 194L, was identified as Saccharothrix mutabilis subsp. chichijimaensis subsp. nov. The antibiotic exhibited broad antimicrobial activity against Gram-positive and Gram-negative bacteria in vitro. It also exhibited strong cytotoxic activity against P388 leukemia cells and showed antitumor activity against P388 leukemia. The apparent molecular formula of tetrazomine was determined as QJH^N^g. It has a rare structure which consists of six rings including piperidine, piperadine, oxazole, and pyrrolidine.

An actinomycete isolate designated as TS-1980 with multiple resistance to aminoglycoside antibiotics was found to produce novel antibiotics. The strain showed taxonomic features identical to the type strain of Nocardiopsis mutabilis except for the temperature range for growth and the utilization of mannitol and raffinose. Based on the capability of growing at lower temperature range, the strain was named N. mutabilis subsp. cryophilis subsp. nov. Physico-chemical and biological characterization of a purified antibiotic revealed its novel polyamine-type nature with a broad antimicrobial activity. The antibiotic was named dopsisamine.As reported previously1,2), naturally-occurring actinomycete strains with multiple resistance to wide ranges of aminoglycoside (AG) antibiotics show a high probability of antibiotic production.