[Antimicrobial activity of Laetiporus sulphureus strains grown in submerged culture].

Cultural conditions for growth and fruit body formation were elaborated to four strains of Laetiporus sulphureus isolated from nature. All strains demonstrated antimicrobial activity against a wide spectrum of gram-positive and gram-negative bacteria during agar and submerged cultivation including methicillin-resistant strain of Staphylococcus aureus (MRSA) and glycopeptide-resistant strain of Leuconostoc mesenteroides. Antifungal activity was not found.

[Effect of penicillin precursors on antibiotic biosynthesis in various strains].

The regularities of biosynthesis of 6-aminopenicillanic acid (6-APA), benzylpenicillin (BP) and phenoxymethylpenicillin (PMP) by the strains under the investigation did not significantly differ. In the absence of the precursor both the strains mainly synthesized 6-APA. Phenylacetic acid (PAA) and phenoxyacetic acid (POAA) provided directed biosynthesis: the fungus synthesized BP or PMP depending on the precursor nature.

[Effect of the methods of sterilization on the quality of nutrient media and on the level of antibiotic production].

It was shown that conditions for heat sterilization of nutrient media for biosynthesis of antibiotics had an impact on their biochemical composition and activity of a fermentation broth in production of penicillin and erythromycin. The temperature of 120 degrees C and the time of 25 minutes proved to be optimal for sterilization of the media in regard to both preservation of their biochemical composition and providing of the maximum antibiotic productivity on the one hand and maintenance of the sterility during the fermentation process on the other hand.

[Ampicillin pharmacokinetics in prostatic adenoma patients].

Studies on ampicillin pharmacokinetics in patients with prostate adenoma showed that adenoma did not influence the antibiotic kinetics. The ampicillin maximum concentration in tissues and organs of the urinary corresponded to the peak concentrations in blood. Therefore, development of dosage regimens providing the drug efficient concentrations in tissues and organs of the urinary tract should be based on ampicillin kinetics in the blood.

[Oil and fat metabolism and the biosynthesis of penicillin].

When grown on media with vegetable oils the producer of penicillin was more sensitive to changes in the conditions of mass transfer. Their worsening resulted in a more significant decrease in the level of the mycelium productivity than that of media containing animal fats. The observed differences were associated with the fact that the rate of consumption of readily assimilated fat substrates, for instance sunflower oil, by the cells was sufficiently high even at defective aeration and agitation.

[Physiological role of vegetable oils during penicillin biosynthesis].

Addition of liquid vegetable oils to nutrient media decreased the intensity of penicillin biosynthesis. The unfavourable effect of the oils was more pronounced at the beginning of the process while they were not completely utilized. Sunflower oil is a readily assimilated source of carbon.

[Nitrogen metabolism characteristics of P. chrysogenum in relation to penicillin biosynthesis].

Quantitative correlation between the nitrogen level in the mycelium of P. chrysogenum and biosynthesis of penicillin was shown. With an increase in the nitrogen level of the mycelium, its productivity with respect to the formation of the antibiotic also increased.

[Characteristics of cephalosporin C biosynthesis on a synthetic medium].

The attitude of the cephalosporin C-producing organism to various sources of carbon and nitrogen was studied. Carbohydrates such as maltose, starch and sucrose and nitrogen sources such as mineral ((NH4)2SO4 + KNO3) and organic nitrogen (asparagine) may be successfully used for the culture growth and antibiotic biosynthesis. The use of the mineral nitrogen necessitates additional regulation of pH during the cultivation process.

[Physiological role of fats in the process of penicillin biosynthesis].

The level of penicillin production in the presence of whale oil was shown to be higher. The stimulating effect of the oil was connected with accumulation of large biomass rather than with its specific effect on the biosynthesis. At the beginning of the process the oil eliminated the biomass accumulation lag-phase connected with beta-galactosidase repression by glucose.

[Penicillium chrysogenum mycelial productivity in the 1st phase of penicillin biosynthesis].

The course of the mycelium low productivity during the first phase of the usual two-stage process of penicillin biosynthesis was studied. It was found that the low productivity of the mycelium at the beginning of the fermentation process was probably associated with catabolic regression of the penicillin-producing system. The high specific growth rate registered in the experiments (0.

[Pharmacokinetics of cephalexin and cephradine in surgical patients].

Pharmacokinetics of 2 oral cephalosporin antibiotics, i.e. cephalexin and cephradin in surgical patients with normal function of the liver and kidneys was studied.

[Study of the effect of microconcentrations of glucose on the biosynthesis of penicillin].

A method of "acute" experiments with significant dilution of the fermentation broth is proposed for studying the effect of easily assimilable substrates on growth of the culture and production of the antibiotic by it. The effect of microconcentrations of glucose on the parameters of the process kinetics was studied with respect to penicillin. The specific effect of microconcentrations of glucose on the specific rate of the culture growth and productivity was noted.

[Abortive myxovirus infection in Ehrlich's ascitic carcinoma cells. Further study of the nature of the virus-specific structures produced by heterokaryons].

Fowl plague virus-infected cells of Ehrlich ascitic carcinoma produce a noninfectious virus which is defective in fragility of its membranes. An attempt has been made to produce nondefective virus by fusion of infected Ehrlich cells with permissive cells: infected and non-infected chicken fibroblasts. The fusion of FPV-infected and 3H-uridine labeled Ehrlich ascitic carcinoma cells with infected unlabeled chicken fibroblasts using inactivated Sendai virus resulted in production of two types of labeled virus particles: with a buoyant density in cesium chloride gradient of 1.

[Metabolites toxic for penicillin biosynthesis in P. chrysogenum fermentation].

Substances toxic for biosynthesis of penicillin accumulated in the medium at the end of the process during penicillin fermentation. Accumulation of such substances was associated with the mycelium autolysis. Addition of nutrient substances as soon as they are consumed prevented autolysis of the mycelium and accumulation of the toxic metabolites.

[Biosynthesis of penicillin and the biphasal development of a P. chrysogenum culture].

The two-phase pattern of penicillin biosynthesis was observed only under definite cultivation conditions. When the conditions of the culture growth changed, the productivity curve also changed. The most high productivity levels on the glucose medium and the medium with glucose and lactose were noted at the beginning and in the middle of the process respectively.

[Carbon metabolism under conditions of regulated penicillin biosynthesis].

Carbon metabolism of P. chrysogenum under conditions of periodical addition of the nutrients was studied. It was found that a proper rate of the carbon source addition to the culture was of significant importance for intensive biosynthesis.