Antibiotic Agent

The following examples illustrate the invention but are not to be construed as limiting.

Preparation of Mutant Z. arboricola MF 5533 ATTCC 74030

A frozen vegetative mycelium of Z. arboricola MF5404 ATCC 20957 was inoculated into 50 milliliters of KF seed medium contained in a 250 milliliter Erlenmeyer flask and N-methyl-N'-nitro-N-nitrosoguanidine (NTG) was added to a final concentration of 7.5 micrograms per milliliter. The flask was shaken at 220 rpm at 25.degree. C. for five days to obtain broth containing cells grown in the presence of NTG. A portion of the broth was plated on the surface of potato dextrose agar and the plates incubated for 14 days at 25.degree. C. to obtain spores of the microorganism. The spores were harvested, diluted in sterile saline and plated on the surface of potato dextrose agar and incubated at 25.degree. C. for 7 days for colony formation. The colonies were isolated by transferring each colony to separate slants of potato dextrose agar. The inoculated slants were incubated at 25.degree. C. for 14 days and a plug from the slants separately taken and inoculated into 20 milliliters of KF medium to produce seeds, then, 2 milliliters of the seed used to inoculate 40 milliliters of SP-5 medium which was then incubated at 25.degree. C. for 14 days. The broth then was extracted with methanol and the extract tested for the production of Compound X and other components by HPLC. One of the slants designated Culture 47-19 was used in the production hereinafter described. Culture 47-19 was subsequently re-isolated and preserved in the Merck Culture Collection as MF 5533.

Seed cultures were first prepared in several stages. As an initial step, 54 milliliters of P34-2 medium was inoculated with a plug from a frozen vial of Zalerion arboricola tentatively designated Culture 7-19 and subsequently re-isolated and preserved in the Merck Culture Collection as MF5533. The inoculated medium was incubated with shaking at 220 rpm at 25.degree. C. for four days. A twenty-milliliter sample of this seed medium was used to inoculate each of four 2-liter flasks containing 500 milliliters of P34-2 medium and the inoculated medium incubated at 25.degree. C. for four days at 220 rpm. The flask contents were then pooled and used to inoculate a 300-liter seed fermenter containing 180 liters of P34-2 medium and 2 milliliters/liter of polypropylene glycol P-2000 to reduce foaming. The fermenter was operated for six days at a temperature of 25.degree. C, an air flow of 90 liters per minutes, a pressure of 0.7 kg/cm.sup.2 gauge, and an agitator speed of 200 rpm. A 25 liter sample of this seed then was used to inoculate an 800 liter seed fermenter containing 475 liters of P34-2 medium and 2 milliliter/liter of P-2000 and cultivated for four days at 25.degree. C., air flow of 250 liter/minute, a pressure of 0.7 kg/cm.sup.2 gauge and agitator speed of 150 rpm.

425 liters of the seed broth thus prepared was inoculated into 13,700 liters of TG 106 medium in a 19,000 liter production fermenter. Fermentation of the mixture was carried out at a temperature of 25.degree. C., air flow of 6300 liters/minute, a pressure of 0.7 kg/cm.sup.2 gauge and agitator speed of 80 rpm. The pH was allowed to decrease from an initial value of 6.0 to 5.5 and then maintained at 5.5.+-.0.2 using sodium hydroxide or sulfuric acid. The cultivation was continued for twelve days, after which time the broth was harvested for product isolation.

3100 gallons of whole broth was first extracted with 1900 gallons of methanol. The methanol was clarified by centrifugation to obtain 4250 gallons of clarified liquid as first extract and 650 gallons of solid. The latter was re-extracted with 1500 gallons of methanol and centrifuged to obtain 1550 gallons of clarified liquid as second extract. The solids from this centrifugation were extracted with 1500 gallons of 80 percent aqueous methanol and centrifuged to obtain a third extract.

The first extract was loaded on an SP-207 (brominated polystyrene-divinylbenzene copolymer) adsorption column and washed with 65% aqueous methanol. Some product breakthrough was noted in the 65 percent methanol wash.

The 65 percent methanol wash and selected side outs from the first SP-207 column, amounting to 900 gallons, were combined with the second and third extracts from the whole broth and combined extracts totalling 4050 gallons were absorbed on an SP-207 column and eluted with 100 percent methanol.

The rich cut eluate from the first SP-207 column was diluted, adsorbed and eluted with 100 percent methanol from an HP-20 columns. The rich cut eluate from the second SP-207 column was combined, diluted with water, adsorbed to two HP-20 columns, and eluted with 100 percent methanol.

The three HP-20 rich cut eluates were combined, diluted With water and then adsorbed and eluted with 100 percent methanol from an SP-207 column for concentration and dewatering. the rich cut was concentrated 4.times. by distillation.

To a 500 ml aliqnot of the 4.times. concentrate from the foregoing columns was added 4.5 liters of isopropyl acetate to separate the product which precipitates from P-2000 which remains in solution.

The precipitate was then prepared for preparative HPLC to be carried out on a commercial column identified as Doff-Oliver Peak Performer equipped with a Prochrom LC 150 VE 15 cm. column charged with 3 kilograms of `MATREX` irregular silica gel (AMICON) of 20 .mu.m particle size, 60 .ANG. pore size. In the preparation the precipitate was first filtered, vacuum dried, and dissolved in 550 milliliters of 2:2:1 ethyl acetate/methanol/5% acetic acid solvent mixture. The solvent composition was then adjusted to the feed composition of 76/16/8 ethyl acetate/methanol/5% aqueous acetic acid and 715 milliliters of the mixture was immediately injected onto the Prochram LC 150 VE column at a flow rate of 605 ml/min. using the mobile phase of 80/10/5 ethyl acetate/methanol/5% aqueous acetic acid and twenty-two 2-liter fractions collected.

Fraction 16 was concentrated to dryness and 100 milligrams of it was reconstituted in 2 milliliters of 80:20:2 methylene chloride/methanol/water. The solution was filtered to clarify it and the clear solution injected onto a 50 centimeter.times.22.5 millimeter WHATMAN silica gel HPLC column. The mobile phase for the chromatography was 80:20:2 methylene chloride/methanol/water and the flow rate was 10 milliliters/minute. The chromatography was monitored using UV detector at 276 nm and also by analytical HPLC of the fractions. Both detection methods indicated a baseline separation of Compound IA, IB and X, all of which were present in the original mixture.

A total of nine identical injections were performed in the manner above indicated and the factions containing compound IA were combined, concentrated to dryness and reconstituted into 100 milliliters of 50:50 methanol/water. This solution was adsorbed to 20 milliliters of HP-20, eluted with methanol and dried under vacuum to obtain 91 milligrams of Compound IA.

The remaining 4.times. concentrate from the third SP-207 column in Example 3 was added to 10 volumes of isopropyl acetate to precipitate Compound X, IA and IB. The precipitate was collected by centrifugation and the material chromatographed on four 500 ml silica gel columns eluted with 85:10:5 ethyl acetate/methanol/5% aqueous acetic acid. A composite sample from one of the silica columns containing 60 g of Compound IB and 20 g of Compound IA (as determined by HPLC) was chromatographed on a 150 liter silica column run in a similar manner. Four 50 gallon fractions were collected followed by twenty-three 15 gallon fractions. One of the 15 gallon fractions rich in Compound IB (>95% as determined by HPLC) was concentrated to dryness, reconstituted in ethyl acetate/methanol/water (76/16/8) and further purified on a 1 liter silica column, eluted with 85/10/5 ethyl acetate/methanol/5% aqueous acetic acid. The rich cuts were combined, concentrated, redissolved in 50/50 MeOH/H.sub.2 O and desilicated on a 40 ml HP-20 column. Compound IB was eluted with 100% MeOH. The cuts rich in Compound IB were combined, subjected to a rotary evaporator to vaporize the methanol and obtain an aqueous solution which was lyophilized to obtain Compound IB as a white powder. The white powder had the spectral characteristics set forth previously for Compound IB.

In a manner similar to that described in Part A of Example 1, mutant MF 5533 was obtained from MF 5404 except that the seed from the seed flasks were used to inoculate 40 milliliters of TG-106 medium and the latter incubated at 25.degree. C. with shaking at 25.degree. C. for 14 days.

1000 tablets, each containing 500 milligrams of Compound IA are prepared from the following formulation:

The finely powered ingredients are mixed well and granulated with 10 percent starch paste. The granulation is dried and compressed into tablets.

1000 hard gelatin capsules, each containing 500 milligrams of Compound IB are prepared from the following formulation:

A uniform mixture of the ingredients is prepared by blending and used to fill two-piece hard gelatin capsules.

250 milliliters of an injectable suspension are prepared by conventional procedures having the following formulation:

The ingredients are blended and thereafter sterilized for use.

An ointment suitable for topical application may be prepared by intimately dispersing 13 milligrams of Compound IA in 1 gram of commercially available polyethylene/hydrocarbon gel.

An aerosol composition may be prepared having the following formulation:

A culture of Z. arboricola ATCC 20868 was grown on potato dextrose agar in petri plates at 25.degree. C. for 3 weeks. Ten milliliters of 0.3M TRIS buffer, pH 7, were added to the plates and the spores scraped off the surface into the buffer with a sterile cotton swab. The suspension in the buffer was decanted off and the procedure repeated twice. The spore suspensions were combined and filtered through glass wool to remove large clusters of spores. The suspension filtrate was centrifuged at first at 600 rpm then at 700 rpm and finally at 800 rpm, each time for 3 minutes with the pellet being discarded after each centrifugation. The supernatant liquid from the third centrifugation was then centrifuged at 3000 rpm for 5 minutes. The pellet from this centrifugation was resuspended in 3 milliliters of 0.3M TRIS buffer and used for mutagenic treatment. This suspension contained from 10.sup.3 to 10.sup.4 spores per milliliter.

To the spore suspension was added 100 .mu.g/ml of N-nitroso-N-methylurethane and the resulting mixture shaken at 300 rpm for 20 minutes at room temperature. At the end of this period, the mixture was centrifuged and the supernatant liquid was removed. The pellet was washed twice with 0.3M TRIS buffer pH 7.0 and then resuspended in the same buffer and after appropriate dilutions plated on potato dextrose agar for forming isolated colonies. The plates were incubated at 25.degree. C. for two weeks for colony formation. The colonies were isolated by separately transferring to slants of potato dextrose agar. The inoculated slants were incubated at 25.degree. C. for 10-14 days and a plug from the slants taken and tested for the production of Compounds X and other components in the fermentation by HPLC assay. A plug from one of the slants initially designated as Z7-9, was placed in the Merck Culture Collection as MF 5404 and deposited with the American Type Culture Collection as ATCC 20957.