[Comparative study of a group of mutant strains of Trichoderma viride, producer of cellulolytic enzymes]. / Sravnitel'noe izuchenie gruppy mutantnykh shtammov Trichoderma viride, produtsenta tselliuloliticheskikh fermentov

In the course of selection of Trichoderma viride, the producer of cellulolytic enzymes, the group of mutant strains characterized by a higher level of productivity are isolate. It is shown that the isolated mutants possess a number of common but differing them from original strains characters. These include: the small size of colonies ("dwarfs"), a lower capacity to carry out some biochemical reactions, and increased development rate and a higher resistance to lethal effect of nitrosoguanidine and nitrosoethyl urea. The data obtained indicate that in the series of populations of successively isolated mutants observed the stabilization of variability of the levels of C1 enzyme synthesis takes place. It is also shown that, unlike original cultures, the populations of mutant strains are characterized by a higher variability of Cx enzyme activity levels as compared with C1.

[Effect of preservation conditions on the viability and activity of Streptomyces griseus--producer of the antibiotic grizin]. / Vliianie uslovii khraneniia na zhiznesposobnost' i aktivnost' Streptomyces griseus--produtsenta antibiotika grizina.

Strain AURIGenetics- 1552 of Str. griseus producing grisin used as a feed additive was obtained in the course of stepped selection. It is deposited at the Central Collection of Industrial Microorganisms of the USSR and designated as strain S-248. The strain was stored under varying conditions and their effect on its viability, morphological variation and antibiotic potency was studied. Investigation of the strain variation with respect to the cultural and morphological properties and the antibiotic production revealed definite correlation between the morphological properties of the culture and its capacity for the synthesis of the antibiotic. The medium G-1 containing KNO3 as the only source of nitrogen was found to be advantageous for maintaining the strain potency on storage with the method of subcultures or under a layer of mineral oil. It was shown that the strain can be successfully stored by lyophilization. This method in combination with selection of active variants from populations of lyophilized cells provided not only maintenance of the culture potency at the required level but also its increase.

[Study of natural mutiple drug resistance in actinomycetes of the genus Streptomyes]. / Izuchenie prirodnoi mnozhestvennoi lekarstvennoi ustoichivosti u aktinomitsetov roda Streptomyces.

Natural strains of actinomycetes belonging to 3 systematic groups of the Streptomyces genera, i.e. blue, gray and globisporine were characterized for their resistance to antibiotics and sulfamids. The majority of the strains were shown to have stable inherited multiple resistence to a wide variety of antibiotics. Linkage analysis for resistance determinants in pairs showed random distribution of most of the determinants among the members of the blue and grey groups of the actinomycetes. Non-random distribution of the resistance determinants to Tc, Cm and Rm in TcCm, TcRm conbinations for the blue group actinomycetes and to Om, Rm, Fa, Lm, Em, Rm and Tc in OmRm, FaLm, EmPm, TcOm combinations among the members of the grey group of actinomycetes was found.

[Storage of Pseudomonas strains degrading the surfactants]. / Khranenie psevdomonad, razlagaiushchikh poverkhnostno-aktivnye veshchestva.

The survival rate and the destruction activity of Pseudomonas strains decomposing anionic and ampholytic surfactants were studied in the course of their storage for a long period of time. The strains were shown to remain viable and active after being freeze-dried for a year. Therefore, lyophilisation can be recommended as the main method of storage for bacterial strains decomposing the following surfactants: sulfoethoxylate, sulfonate, cyclimide, and amidobetaine.