Search

The influence of various preservation conditions of viability and antibiotic activity of Acremonium chrysogenum 281A and 305A strains producing cephalosporin C was studied. Cryogenization of the culture in the form of suspension of the vegetative mycelium in 20 per cent glycerol solution at a rate of 1 degree/min showed to be advantageous over lyophilization and L-drying. Cryogenization under such conditions provided rather high viability of the culture and preservation of its initial antibiotic activity for the period of its storage for at least 1.5 years in liquid nitrogen at a temperature of -196 degrees C.

Self-organization of various submicroscopic formations, such as "tubes", "ribbons", etc. differing in ultrastructure and containing a polyenic antibiotic was observed in acetone extracts of the mycelium of the "fructose" variant of Actinomyces roseoflavus var. roseofungini. Conditions for separate isolation of the above structures are described. Concentration of the extract and the ratio of the volumes of water added to the extract are determinant for the process of self-organization. A possibility of reorganization of the tubular structures into the ribbon-like ones and vice versa is shown.

When Streptomyces roseoflavus var. roseofungini is grown as a submerged culture in a chemically defined medium with stirring, it yields a number of variants in which the capacity to form the aerial mycelium is disturbed. Inoculations of the submerged mycelium of different age into a solid medium give rise to both "tomentose" variants (TV) with the aerial mycelium and "naked" variants (NV) lacking the aerial mycelium. The latter variants comprise Nocardia-like variants (NLV) with the fragmenting mycelium. The following change in the variants occurs in the inoculations of the submerged mycelium in the course of the cultural growth: TV leads to NV leads to NLV or (more rarely) TV leads to NLV. The dynamics of accumulation of the variants depends, to a considerable extent, on the source of carbon in the medium: NLV first appear on the medium containing fructose; NV are detected first on the medium with glucose; NV are rarely found on the medium with mannitol. In aged cultures, the number of NLV can reach 80--90%, the content of TV is 20--10%, and NV are absent. The above results suggest that the formation of NLV from S. roseoflavus var. roseofungini is the result of stepwise selection.

Crystallinity of tubular structures of Act. roseoflavus var. roseofungini obtained from both the initial culture and the dedifferentiating fructose mutant was shown with the method of roentgen-phase analysis (the difractometric method with ionization registration of reflection)

Adifferentiated Nocardia-like variants (Nv) of Streptomyces roseoflavus var. roseofungini, similar in their cultural characteristics with the variant 1-68 described elsewhere (Nikitina, 1968; Kalakoutskii a. Nikitina, 1976), can be obtained not only in the course of growth of the parent culture on a solid medium containing fructose in the form of secondary colonies, but also during submerged cultivation with stirring. Interruptions in aeration do not affect accumulation of the cells of such variants in the medium. A direct correlation has been established between the amount of biomass and the number of Nv colonies when submerged mycelium is inoculated into a solid medium.

The difference in the growth on fructose between differentiated and adifferentiated variants of Streptomyces roseoflavus var. roseofungini should be attributed to their different capacity in forming the enzyme system for fructose uptake whose action is induced by this carbohydrate. In the cells of the two variants grown on glucose and mannitol, the process of induction occurs in the presence of chloramphenicol. In the cells grown on glycerol, chloramphenicol inhibits the induction. The growth of the differentiated variant on fructose stops apparently due to the exhaustion of endogenous reserves which are necessary for maintaining the system of fructose uptake in the active state.

The antibiotic activity and fractional composition of the supernatant of the homogenate of Actinomyces streptomycini B-6 spores were investigated. The homogenate supernatant was of yellow colour and showed antibiotic activity when used as the test-organism of the culture St. aureus 209. The antibiotic activity was associated not with the homogenate pigment but with the colourless substance referring to streptomycins which was contained in spores.

Six aerobic gram-positive nonspore-forming bacterial strains belonging to the Kurthia genus were isolated from the Magadan (Susuman) mammoth found in the permafrost of the East Siberia. The strains are a phenotypically homogeneous group different from the two known species (K. zopfii and K. gibsonii) in requiring more vitamins, the absence of growth in a medium with 7% NaCl, and a low level of DNA-DNA hybridization (not more than 45%). Moreover, the strains differ from K. zopfii in the synthesis of a yellow pigment, the activity of phosphatase, and the absence of coccoid forms; the bacteria differ from K. gibsonii in the absence of growth at a temperature above 40 degrees C. The organisms are referred to as Kurthia sibirica sp. nov. The type strain 13-2 has been deposited in the All-Union Collection of Microorganisms as strain VKB B-1549.

As has been shown by electron microscopy, the development of the endosymbiont in the nitrogen-fixing nodules of A. glutinosa proceeds either along the known (hyphae leads to vesicles) or less convenient pattern (hyphae leads to sporangia leads to spores). The paper presents more complete information about the structure of layers which separate the endosymbiont from the cytoplasm of host cells and about changes in the structure of the both partners accompanying sporogenesis.

A synthetic medium was used to obtain the dormant spores of Thermoactinomyces vulgaris. The fraction of the dormant spores depended on the amino acid composition of the growth medium. The rate of growth and development of the organism on the synthetic medium is lower as compared to the routinely employed complex medium.

It has been shown in the course of cultivation in a liquid medium with stirring that the general density of the cell mass is a factor preventing the accumulation of an adifferential mutant variant in the culture of Streptomyces roseoflavus var. roseofungini 1128. The mass of dead cells acts similarly to the living biomass.

Endospores of Streptomyces streptomycini B-16 are considerably more thermostable (by 40degreesC) than it was generally accepted. The bulk of populations of the spores (up to 55%) can be subjected to 100degreesC during 10 min but does not germinate under usual conditions as a result of heat damage which may be repaired at a relative humidity of 100% or in water suspensions at temperatures optimal for growth of the actinomycete. The rate of reparation increase upon washing of the heated spores with stirring, centrifuging and especially after treating the spores with ultrasound. The treatment is supposed to eliminate from the spores growth inhibitors which were formed as a result of heat damage. Characteristics of the process are discussed, which make it different from other reparation systems described elsewhere, in particular its endogenous character.

Tubular formations analogous by their structure to those found on the surface of the outer sheath of the hyphae of the aerial mycelium of Actinomyces roseoflavus var. roseofungini were reconstructed in vitro from the mycelium acetone extract on addition of water. A polyenic antibiotic was shown to be present in the composition of the "tubes". A possible role of the antibiotic in the genesis of the secondary structures of the actinomycete is discussed.

Comparative studies were made employing thirteen new isolates of Kurthia zopfii and strain ATCC 10538. It was shown that the cell wall of K. zopfii contained lysine, glycine, alanine, leucine, valine, aspartic and glutamic acids, ribose. The guanine plus cytosine content of deoxyribonucleic acid was 37-38 mol%. The simple post-fission cell movement was demonstrated. The obtained results are discussed against the practice of including the Kurthia into the group of coryneform bacteria.

Properties of a dark-brown pigment complex isolated from the spores, mycelium and cultural broth of Actinomyces umbriferus by a conventional technique were compared. The complex consists of three fractions: one is a true melanin while two other fractions differ by several characteristics from melanins and from each other. The fraction which is most similar to melanin prevails in the spores, is contained, in a relatively small amount, in the mycelium, and is absent from the cultural broth. Melanin isolated from the spores has a low relative content of carbon and nitrogen and a higher ash content as compared to melanin isolated from the vegetative mycelium. The pigment complex of the spores is characterized also by differences in properties of the first isolated fraction. The pigment complex from the cultural broth differs from the complex of the mycelium and spores by properties of the studied fractions.

During joint cultivation of the actinomycetes Streptomyces griseus (strains 65 and 744) isolated from the soil and the green algae Chlorella vulgaris larger amount of biomass as compared with solitary axenic culture have been shown. The relation of biomass of actinomycetes S. griseus strain 65 and S. griseus strain 744 and algae in the lichen-like experimentally formed thallom make up 42:1 and 40:1 relatively, i. e. the mass of actinomycetes forms 97-98% from the mass of thalloms. Actinomycetes in the associations with the algae accumulate larger amount of biomass that in the axenic cultures on corresponding medium, whereas the algae produce the same amount of the biomass as the axenic culture under the same conditions. The associations have the antimicrobic properties differed from the axenic cultures established.

When grown on the solid synthetic medium with glucose as the only carbon source the dedifferentiated "fructose" mutant of Actinomyces roseoflavus var. roseofungini accumulated aggregates of tubular-like structures. The individual tubules had the internal diametre of 80 A and external diametre of approximately 200-220 A. These structures were isolated as a distinct fraction and their non-protein nature was demonstrated. They were easily soluble in acetone and reconstitutable in vitro. The possible significance of production of self-assembling structures by a mutant with impaired differentiation is discussed. The possibility of involvement of self-assembly processes in the formation of surface sheath of aerial mycelium in normally differentiating actinomycetes is mentioned.