[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.

[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.

[Inhibition of oleandomycin biosynthesis by glucose]. / Podavlenie biosinteza oleandomitsina gliukozoi.

The results of the study on the effect of glucose and various carbohydrates on biosynthesis of oleandomycin by Streptomyces antibioticus are presented. It was found that glucose added at the beginning or by the 48th hour of the fermentation process on the complex medium inhibited oleandomycin biosynthesis. To investigate the mechanism of the glucose effect, a fermentation medium was developed. It provided variation of the carbohydrate composition, determination of the protein content in the culture and evaluation of the mycelium productivity. With the use of this medium it was shown that monosaccharides such as galactose, fructose and glucose significantly activated the mycelium growth as compared to lactose and sucrose. At the same time glucose completely inhibited oleandomycin biosynthesis when added either as an only carbohydrate component or in combination with galactose or fructose, while the presence of the other two monosaccharides did not prevent antibiotic production, though the mycelium productivity was lowered as compared to that with the use of the disaccharide. Therefore, the inhibitory effect of glucose on biosynthesis of oleandomycin was not connected with activation of the culture growth by it. Acidification of the medium on cultivation of the streptomycete in the presence of glucose only partially explained its inhibitory effect, since inhibition was maintained on the medium with addition of CaCO3 which stabilizes pH. Addition of 2-deoxy-D-glucose, a nonmetabolized glucose analog, to the fermentation medium retarded antibiotic production. It is possible that the inhibitory effect of glucose on biosynthesis of oleandomycin is not associated with its metabolism.

[Biochemical analysis of the microvillose membranes of the small intestine mucosa of dogs after levorin administration]. / Biokhmicheskii analiz membran mikrovorsinok slizistoi obolochki tonkogo kishechnika sobak posle vvedeniia levorina.

The effect of oral levorin used for a prolonged period of time on the lipid composition and activity of alkaline phosphatase and invertase of the microvilli membranes of the small intestinal enterocytes of old dogs was studied. Higher ratios of cholesterol/phospholipids in the membranes and inactivation of alkaline phosphatase and invertase were noted in the old dogs as compared to the young ones. Exposure of the old dogs to levorin had a significant effect on the microvilli membranes of the intestinal epithelial cells. It was evident from a lower ratio of cholesterol/phospholipids in the membranes and stimulation of the alkaline phosphatase activity. It is supposed that the changes in the state of the microvilli membranes of the small intestinal mucosa due to levorin play a definite role in the mechanism of its hypercholesterolemic action.

[NAD+ synthesis in the isolated kidney cell nuclei of dogs after the intravenous administration of amphotericin B]. / Sintez NAD+ v izolirovannykh iadrakh kletok pochek sobak posle vnutrivennogo vvedeniia amfoteritsina B.

A study was made of the synthesis of nicotinamide adenine dinucleotide (NAD+) in the nuclei of kidney cells of dogs under normal conditions and upon the effect of the polyenic antibiotic amphotericin B. An active NAD-pyrophosphorylase has been found in the nuclei of kidney cells. It has been established that a intervenous introduction of amphotericin B stimulates NAD+ production. Amphotericin B also causes a decrease in the amount of histones in the nucleus. In the case of the nuclear membrane damage by a non-ionic detergent Triton X-100, no increase in the synthesis of NAD+ has been observed in the nuclei of kidney cells of animals treated with antibiotics, as opposed to the control ones. Under discussion is a question of a possible mechanism of the effect of polyenic antibiotics on the synthesis and metabolic activity of NAD+.

[Changes in the protein composition of nuclear membranes of canine kidneys induced by amphotericin B in vivo]. / Izmenenie soderzhaniia belkov iadernykh membran pochek sobak pri deistvii amfoteritsina B in vivo.

Intraveneous injection of amphotericin B significantly affects the protein composition of canine kidney nuclear membranes. Electrophoresis in polyacrylamide gel showed that injection of this antibiotic results in a considerable loss or complete disappearance of the histone fractions H1 and H4 (depending on the dose) and a decrease in the content of fraction H3 in the membrane proteins. The fractionation spectrum of other nuclear membrane proteins also shows deviations from normal. One of possible reasons for that is the increased enzymatic degradation of the proteins. It is also probable that the changes in the protein composition of nuclear membranes are due to the presence of sodium deoxycholate in the antibiotic drug and may be accounted for by the nephrotoxic effect of polyenoic antibiotics.

[Biochemical shifts in the nuclear membranes of the kidneys of dogs after the prolonged intravenous administration of amphotericin B]. / O biokhmicheskikh sdvigakh v iadernykh membranakh pochek sobak posle vnutrivennogo prodolzhitel'nogo vvedeniia amfoteritsina B.

The protein composition of the nuclear membranes of the dog kidneys after intravenous infusion of amphotericin B in a dose of 3 mg/kg and sodium desoxycholate in a dose of 1.2 mg/kg for 8 days was studied. It was found that administration of amphotericin B and sodium desoxycholate was accompanied by pronounced changes in the membrane proteins. The changes were evident from a decreased content of histones in the nuclear membranes, elimination of the high molecular components, a decreased quantitative content of some fractions and appearance of low molecular bands. The effect of sodium desoxycholate on the nuclear membrane proteins was shown to be less pronounced than that of amphotericin B. The significance of the data is discussed in connection with high toxicity of polyenic antibiotics. The data provide elucidation of the causes of the nephrotoxic effect of the polyenic antibiotics.

[Changes in ATPase activity of dog kidney nuclear membrane under the effect of polyenic antibiotics]. / Izmenenie ATPaznoi aktivnosti iadernykh membran pochek sobak pod vliianiem polienovykh antibiotikov.

Effect of amphotericin B and nistatin on ATPase activity of dog kidney nuclear membranes is studied in vivo and in vitro. Long-term intravenous injections of the antibiotics do not change the ATPase activity of kidney nuclear membranes. However, short-term injections of polyenic antibiotics have some effect on ATPase activity on nuclear membranes: amphotericin B, considerably activates the enzyme . In vitro incubation of isolated dog kidney nuclei with amphotericin and nistatin at concentrations of 1 and 10 mcg/ml does not affect the activity of nuclear membrane ATPase, while increased concentrations of polyenic antibiotics, (up to 200 mcg/ml) results in a slight inhibition of the enzyme activity. The role of the data obtained for solving molecular basis of the toxic effect of polyenic antibiotics.

[The change of template activity of dog kidney chromtin by polyene antibiotics in vivo and in vitro]. / Izmenenie matrichnoi aktivnosti khromatina pochek sovak pod vliianiem polienovykh antibnotikov in vivo i in vitro

Effect of amphotericin B and nistatin on template activity of nuclear membrane-bound (DNPm) and free (DNPo) dog kidney chromatin after intravenous injections of antibiotics and after the incubation of isolated kidney cell nuclei with the antibiotics is studied. It is found that injections of amphotericin B and nistatin resulted in the increase of DNPo template activity in RNA polymerase system, the stimulating effect of nistatin being higher than that of amphotericin B. Injections of nistatine stimulated also template activity of DNPm, while amphotericin B produced no effect on DNPm. When studing the effect of polyene antibiotics on template activity of DNPo and DNPm in vitro, it is found that the intensity of RNA synthesis after incubation of isolated nuclei with antibiotics is considerably increased, and stimulating effect of nistatin is higher than of amphotericin B. Both antibiotics produced no effect on template activity of DNP in vitro. Thus, comparative analysis of changes in template activity of dog kidney chromatin under the effect of polyene antibiotics in vivo and in vitro has revealed the similarity of these drugs and draws to the conclusion that nistatin and amphotericin B produce a direct effect on template activity of chromatin.

[Effect of polyene antibiotics on isolated dog kidney nuclei]. / Deistvie polienovykh antibiotikov na izolirovannye iadra pochek sobak

Effect of amphotericin B and nistation on caryoplasmic proteins, nuclear membrane-bound chromatin (DNPm) and soluble DNP (DNP0) from dog kidney isolated nuclei is studied in vitro. The yield of caryoplasmic proteins from nuclei is found to be increased during incubation with amphotericin B and nistatin, the content of some fraction in caryoplasmic proteins being decreased while their qualitative composition being unchanged. It is found that the treatment of nuclei with amphotericin B contributes the association of DNP particles with nuclear membrane and the increase of protein/DNA and RNA/DNA ratios in DNPm. No such effects are observed in the presence of nistatin. Both antibiotics do not affect protein/DNA and RNA/DNA ratios in DNP0 fraction. Polyene antibiotics are shown to change considerably the composition of acid soluble proteins in DNP0 and DNPm and in non-histone proteins in DNP0, and not to affect the content of lipids and their fatty acid composition in DNPm. The data obtained are of certain value for explanation of the mechanism of toxic effect of polyene antibiotics on animal cells.

[Effect of polyethylene glycols of linear structure and different molecular weights on rat liver lysosomes]. / Deistvie poliétilenglikolei lineinoi struktury i razlichnogo molekuliarnogo vesa na lizosomy pecheni krysy

The action of nonionic detergents--polyethyleneglycols of the linear structure with various molecular weight (from 700 to 15 000) on the lysosomes of rat liver was studied. Triton X-100 activated the acid phosphatase of the sum total fraction of lysosomes to a greater degree than the rest of the polyethyleneglycols. The action of polyethyleneglycols on the activation of acid phosphatase in the lysosome subfractions was inconstant. The result obtained is explained from the aspect of the morphological and biochemical heterogeneity of lysosomes. On the basis of comparison of personal data and literature data a supposition is put forward that the resistance of lysosomes to the action of the polyethyleneglycols in vitro and in vivo was the same.