[Study of biosynthesis of mycoheptin, mycopentene and fatty acids by Streptoverticillium mycoheptinicum strain 255 in various conditions of its cultivation]. / Issledovanie biosinteza mikogeptina, mikopentena i zhirnykh kislot v razlichnykh usloviiakh kul'tivirovaniia Streptoverticillium mycoheptinicum shtamm 255.

The effect of the fat content in the medium for cultivation of Streptoverticillium mycoheptinium-255 and the effect of glucose intake on the rate of carbohydrate utilization and intensity of incorporation of labeled sodium acetate and propionate to mycoheptin, mycopentene and fatty acids were studied. It was shown that a lower fat content in the medium in comparison with the optimal one resulted in intensification carbohydrate catabolism during an idiophase, increased production rates of mycopentene, an accompanying antibiotic, and fatty acids and a decrease in the heptaene/pentaene ratio. The optimal contents of the oil in the medium provided a decrease in the rate of the carbohydrate consumption and preferable production of the required antibiotic or mycoheptin accompanied by a decrease in the synthesis rate of mycopentene and fatty acids.

[Experimental study of the pharmacokinetics of an amphotericin B derivative]. / Eksperimental'noe izuchenie farmakokinetiki proizvodnogo amfoteritsina B.

Absorption, distribution and excretion of a new water soluble derivative of amphotericin B (NWSDA) were studied after its administration by different routes. After the antibiotic intravenous administration the therapeutic concentrations in blood, organs and urine were shown to remain for prolonged periods. The likely sites of NWSDA deposition were detected with microbiological and radionuclide methods. The most prolonged periods of antibiotic preservation were stated in the renal cortex, spleen and lungs. The ways of NWSDA excretion were studied in operated animals. Only 3.5 per cent of the antibiotic was excreted with urine and bile for 24 hours. The pharmacokinetic parameters of NWSDA after its intravenous administration were estimated. The bioavailability of the antibiotic after its intramuscular and oral administration was found to be low.

[The immunocorrective and detoxifying actions of hemosorption, plasmapheresis and enterosorption in pemphigus]. / Izuchenie immunokorrigiruiushchego i detoksitsiruiushchego deistviia gemosorbtsii, plazmafereza i énterosorbtsii pri puzyrchatke.

Immunity system changes and intoxication characteristics were studied in two groups of patients with pemphigus treated with traditional methods (group 1, 14 patients) and routine therapy combined with hemoperfusion, plasmapheresis, and enterosorption (group 2, 12 patients). During exacerbation pemphigus patients develop manifest changes in the immunity status in the presence of endotoxicosis. Introduction of hemoperfusion, plasmapheresis, and enterosorption in the complexes of treatment of pemphigus patients activates erosion epithelialization, helps sooner reduce the doses of corticosteroids whose total dose is reduced by 39 percent, improves cell-mediated and humoral immunity parameters, and is conducive to a more favorable time course of the body intoxication parameters.

[Inhibition of oleandomycin synthesis by glucoses added during fermentation]. / Podavlenie biosinteza oleandomitsina gliukozoi pri ee dobavlenii v protsesse fermentatsii.

Oleandomycin biosynthesis by Streptomyces antibioticus is repressed by glucose added to the growth medium in the process of fermentation. Phosphotransferase involved in the synthesis of acetyl CoA and propionyl CoA (the precursors of the antibiotic macrolactone ring) is neither inhibited nor repressed, and the substrate specificity of the enzyme does not change. The content of cAMP in the mycelium of S. antibioticus does not change significantly when either glucose or sucrose is added to the medium 24 h after the inoculation whereas the content of exogenous cAMP rises abruptly 24 h after glucose addition. At the same time, the medium becomes much more acidic and the content of protein in the mycelium rises noticeably. Consequently, cAMP may be involved in the regulation of the culture growth.

[Effect of cationic polymers and surface-active substances on bacterial resistance to kanamycin]. / Izuchenie vliianiia kationnykh polimerov i poverkhnostno-aktivnykh veshchestv na ustoichivost' bakterii k kanamitsinu.

The effect of cationic polymers and surface active substances (SAS) on sensitivity of Klebsiella aerogenes 600, Escherichia coli 154 and Proteus vulgaris 7470 to kanamycin was studied. A decrease in the resistance of the above organisms to kanamycin on its use in combination with cationic polymers and SAS was observed. It was shown that such substances inhibited the activity of the enzymes inactivating kanamycin. Their effect was suggested to be due to changes in the lipid surrounding of the enzymes.

[Cyclic adenosine-3',5-monophosphate in Streptomyces antibioticus and its possible role in regulating oleandomycin biosynthesis and the growth of the culture]. / Tsiklicheskaia adenozin-3',5-monofosfornaia kislota u Strptomyces antibioticus i ee vozmozhnaia rol' v reguliatsii biosinteza oleandomitsina i rosta kul'tury.

When glucose is substituted for sucrose in the fermentation medium for Streptomyces antibioticus, the pH of the cultural broth becomes more acidic, the rate of protein synthesis in the mycelium rises, and the rate of oleandomycin synthesis decreases abruptly. The dynamics of cAMP (cyclic monophosphate) accumulation was studied in the process of biosynthesis by the culture in different media. Most of the synthesized cAMP (80-90%) was shown to be excreted into the medium. Glucose stimulates cAMP synthesis and excretion from the mycelium by a factor of 1.5-3. No distinct correlation was found between cAMP content in S. antibioticus cells and the level of oleandomycin biosynthesis. A correlation between changes in the concentration of exocellular cAMP and protein synthesis in the mycelium suggests that the excreted cAMP may be involved in regulating the growth of the culture producing the antibiotic.

[Action of biologically active compounds on kanamycin inactivation by resistant microorganisms]. / Izuchenie deistviia biologicheski aktivnykh soedinenii na inaktivatsiiu kanamitsina ustoichivymi mikroorganizmami.

Products of kanamycin inactivation were identified chromatographically and radiometrically in E. coli 154, K. aerogenes 600 and P. vulgaris 7470. It was shown that the efficiency of kanamycin inactivation in the membrane fraction was 2 times higher than that in cytosol. A decrease in the culture resistance to kanamycin was observed, when the antibiotic was used in combination with the main proteins or phosphonites: a 16-64-fold decrease in the kanamycin MIC. Comparison of the data on the efficiency of the inactivation inhibition by intact cells and in acellular extracts suggests that the effect of protamine on this process is mediated by the cell membrane, whereas phosphonites can also directly interact with the enzymes inactivating the antibiotic.

[Makeup and properties of E. coli cells with a varying level of resistance to tetracycline]. / Sostav i svoistva kletok E. coli s raznym urovnem ustoichivosti k tetratsiklinu.

Lipopolysaccharide composition of tetracycline sensitive and resistant strains of E. coli was studied comparatively. It was shown that that resistance of E. coli to tetracycline was probably due to the differences in the lipopolysaccharide component composition of the outer membrane. On the basis of the activity comparison of the Mg2+- and Ca2+-activated ATP-ase of the membrane fraction of the tetracycline sensitive and resistance strains of E. coli it was concluded that the resistance development in the strains tested to tetracycline was not associated with the changes in the ATP-ase activity.

[Lipid composition of Escherichia coli cells sensitive and resistant to tetracycline]. / Sostav lipidov v kletkakh Escherichia coli, chuvstvitel'nykh i ustoichivykh k tetratsiklinu.

The following variants of E. coli resistant to tetracycline have been obtained from a strain of E. coli W-677 susceptible to 2.5 mcg/ml of the antibiotic: Ri, a recombinant resulting from crossing E. coli W-677 (recipient) and E. coli CSH-222 (donor), resistant to 200 mcg/ml of tetracycline; R2, a strain isolated upon numeros passaging E. coli W-677 on media containing the antibiotic, resistant to 25 mcg/ml of tetracycline. The ability of the resistant variants to bind the antibiotic decreased, as was found in experiments with 14C-tetracycline. Preincubation with low concentrations of the antibiotic resulted in an additional decrease of the sorption by the resistant variants, and in a decrease by 15--18 per cent in the case of the susceptible culture. The R2 variant differed in lipid composition from the parent, susceptible culture: it contained less total lipids and unsaturated fatty acids, and more branched fatty acids. The R1 variant hardly differed in lipid composition from the susceptible culture.