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Morphological, cultural and physiological properties of actinomycete L10-0208 were studied. It was shown that actinomycete was a new natural variant. It was named Streptoverticillium alboreticuli var. kokandum. The physico-chemical characteristics of the pentaenic antibiotic are presented and its originality is shown. The antibiotic is named kokandomycin.

Freezing of Act. noursei cell suspensions at a rate of 0.5 degrees per minute in the presence of various substances showed that 5 per cent concentrations of glycerol, ethylen-, diethylen-, propylenglycol and polyethylenglycols had a cryoprotective effect. Polyethylenglycols with a molecular weight of 1500-20 000 had the highest protective effect on the actinomycetous cells from the damaging action of repeated freezing and thawing. The method of repeated freezing and thawing is recommended for studying the cryoprotective effect of various compounds.

Viability, morphologo-cultural features and antibiotic properties of Sv. hachijoense, strain LIA-0052 stored for 10 years in a dry state and in the state of a resting culture were studied. Spores and mycelium of 2-week strains most stable to some chemical and physical factors were used for drying. It was found that viability of strain LIA-0052 was maintained for a longer period of time after lyophilization, in garden soil and agar culture under a layer of mineral oil. By the end of the observation period the viability of the soil culture decreased and the morphologo-cultural properties were stabilized. When the strain was cultivated on media with sucrose, the level of its antibiotic activity increased.

An actinomyceteous strain LIA-0185 producing a heptaenic non-aromatic antibiotic of the candidin type was isolated from a soil sample taken in the Georgian SSR under the programme of screening antifungal antibiotics. The taxonomic study of the strain showed that it belonged to the series of viridoflavum and had the following main taxonomic features: the sporophores in the whorls, straight, remote: the aerial mycelium from yellow to dark-olive-grey; the substrate mycelium olive; the soluble pigment absent; the melanine pigment was produced on the peptone medium; the culture formed H2S; assimilated glucose, mannose, inozide and to a lesser extent fructose; did not assimilate arabinose, xylose, sucrose, lactose, ramnose and raffinose. The strain inhibited the growth of yeast and fungi, grampositive bacteria and actinomycetes and produced a complex of non-aromatic heptaenic antibiotics. The actinomycete differed from the other whorl cultures. It was classified as a new species Sv. griseoviridum sp. nov. The antibiotic complex was a mixture of 2 components, i. e. I and II present approximately in equal amounts. Component II was analogous to candidin. Component I was a new original substance.

Actinomycete LIA-O832 was isolated from a soil sample of Greece. By its antimicrobial spectrum, morphological and cultural properties the actinomycete was most close to Act. chromogenes but differed from the latter by the antibiotic and physiological properties. The actinomycete was classified as Actinomyces chromogenes var. nov. The culture produced an antibiotic complex including 4 antibiotics, i.e. a tetraen antibiotic primaricin, a new hexaen named grecomycim and 2 non-polyenic antibiotics, one of which was close to kikumycin and the other was close to aksenomycin. The physico-chemical characteristics of the antibiotics are presented.