Action of tetracycline and sodium deoxycholate combinations on protein and nucleic acid synthesis in the cells of the NAG vibrio, Staphylococcus aureus and Escherichia coli]

The effect of tetracycline combination with sodium desoxycholate, a surface-active substance, on the synthesis of proteins and nucleic acids in the cells of NAG-vibrio, Staph. aureus and E. coli was studied by incorporation of 1-14C-glycine and 8-14C-adenine into proteins and nucleic acids. It was found that sodium desoxycholate suppressed the synthesis of proteins and nucleic acids in the cells of NAG-vibrio and Staph. aureus. Its combination with tetracycline resulted in summation or increase of the suppressive effects on proteins and nucleic acids as compared to the effect of the substances used alone. Sodium desoxycholate even in very high concentration, up to 12800 gamma/ml, had no effect on the synthesis of proteins and nucleic acids in the cells of E. coli and respectively it did not change the activity of tetracycline on combined use.     

Stability of deoxyribonucleic acid methylated in the intact animal by administration of dimethylnitrosamine. Rate of breakdown in vivo and in vitro at different dosages

1. The effect of administration of various dosages of dimethylnitrosamine on the extent of methylation of liver and kidney nucleic acids in the intact rat was studied. Methylation of liver nucleic acids was linearly related to the dosage, but decreasing the dose produced relatively less lowering of the extent of alkylation of kidney nucleic acids. 2. The rates of disappearance of 7-methylguanine from DNA during the 2 days after administration of dimethylnitrosamine in the intact animal and on incubation under simulated physiological conditions in vitro were compared. At a high dosage this rate was greater in vivo than in vitro. At a low dosage the small difference between the two rates was not thought to be sufficient evidence for existence of a specific enzymic excision of the abnormal base.     

Effect of castration on purine biosynthesis in the rat liver and kidney

With the present study, the effects of testosterone deficiency on the biosynthesis of purine nucleotides and nucleic acids in rat liver and kidney has been investigated. 20% homogenates were prepared in 1 N HCl04, centrifuged and the nucleic acid were extracted from the precipitate with 0.7 N PCA (15 min at 90 degrees C): the acid-soluble purines were precipitated with 1 M AgNO3 from the supernatant of the centrifuged homogenate, then extracted with 1 M HC1. An increase of the specific activity of the liver (A, +49%; G, +47%) and of the kidney (A, +54%; G, +34%) has been observed (P less than 0.05), while no variation of the specific activity of nucleic acids was evident after castration.     

Histoenzymological and biochemical changes in the liver of adult female rats and of youngs born from Madiol-treated pregnant rats

The effect of a 30-day treatment with Madiol was studied on the activity of some enzymes, nucleic acids, protein and glycogen content of the liver of adult female rats and youngs born from mothers treated during pregnancy. Madiol caused a significant increase in SDH and Atp-ase activity, and decreased glycogen and acid phosphatase.     

Lipid-mobilizing effect of reduced glutathione and its intensifying action on lecithin-cholesterol acyltransferase activity in blood serum of rats

Effect of reduced glutathione (50 mg/100 g) on lipid distribution between organs (liver and kidney) and lecithin-cholesterol acyltransferase (LCAT) activity in blood serum of rats was investigated. The accumulation of common lipids as a result of speeding up the absorbtion of blood serum unsaturated fatty acids and relative decrease of lipids unsaturation in the liver and lipid content dynamics in kidneys owing to the intensification of two processes in this organ: the transport of polyene fatty acids in composition of blood serum lipoprotein lipids to kidney cells and peroxidation of membrane phospholipids were found out. The activating effect of GSH (in vivo and in vitro) on LCAT activity of rat blood serum was shown. It was summarised that GSH-intensification of blood serum etherification ability may be a basic component of reduced glutathione lipid mobilization effect.     

Determination of the nucleic acids in pig embryonic kidney cells by magnetic cytaphoresis

Gallocyanine-chrome alum-stained pig embryonic kidney cells have paramagnetic properties. They move under the influence of gradient magnetic field (magnetophoresis). The velocity of magnetophoresis is proportional to the content of nucleic acids in cells. This allows to estimate the content of nucleic acids per cell dry weight by magnetophoresis and analytical centrifugation.     

Effects of cortisone on regenerating rat liver

The effects of continuous administration of cortisone on the metabolism of regenerating rat liver have been studied. Whereas the restoration of the weight of the liver after partial hepatectomy was not markedly affected by cortisone, the multiplication of cells was reduced to a significant degree after the first 2 days of regeneration. Liver restoration in terms of nucleic acids was similarly inhibited by cortisone. The results are consistent with the interpretation that the inhibition of cell multiplication in this system is dependent on and keeps pace with the inhibition of nucleic acid synthesis by this drug. At almost any time after hepatectomy, the nucleic acid content of the liver cells was the same in treated and in untreated animals. In ancillary studies, it was shown that cortisone caused the cells of regenerating liver to be increased in size and weight through the increased infiltration of lipids. Changes in water, protein, and carbohydrate content of the liver cells did not contribute to this increase in the weight of the cells. Since all animals were treated with cortisone for 5 days before hepatectomy, data were also obtained on the effect of this agent on the resting liver. This course of treatment brought about a significant decrease in the number of cells per unit wet weight and in the water content of the livers. The nucleic acid content of the cells at hepatectomy, on the other hand, was unchanged.     

Study of the action of nystatin on the plasmatic membranes of the liver of rabbits]

The effect of mystatin on the plasmic membranes of the rabbit liver after intravenous administration of the antibiotic to the animals in a dose of 5 mg/kg was studied. It was found that intravenous administration of nystatin had no effect on the quantitative content of protein, lipids and nucleic acids in the plasmic membranes of the liver. The method of electrophoresis in polyacrylamide gel revealed significant changes in the composition of the liver membrane protein due to the treatment with nystatin. The effect of nystatin on the composition of lipids and fatty acids contained in the membrane lipids was also investigated. The data of the thin layer chromatography showed that nystatin did not affect the qualitative composition and the content of separate lipid fractions in the lipids of the liver plasmic membranes. However, the fatty acid analysis of the membrane lipids after intravenous administration of nystatin revealed a number of qualitative and quantitative differences in the composition of the lipid fatty acids of the membranes tested. The results showed that nystatin affected the membrane structures of the rabbit liver cells.     

Electron microscopic and histochemical examination of hepatocytes in rat embryos exposed to the effect of a static electric field]

Static electric field with intensity of 150-80 V/cm has no teratogenic and embryolethal effect on the rat embryos. However, it provokes disturbance of the morphofunctional state of embryo liver, causes destructive-dystrophic changes in the parenchyma cells, decreases the content of nucleic acids, induces disturbances of the membrane systems of mitochondria and other cell structures.     

Binding of [-14C]aflatoxin B1 to cellular macromolecules in the rat and hamster.

The uptake and binding of ring-labelled [-14C]aflatoxin B1 (AFB1) by rat and hamster liver and kidney has been studied, the former species being extremely sensitive to the carcinogenic action of AFB, whereas the latter is resistant. In contrast to an earlier report (Lijinsky et al, Cancer Res., 30 (1970) 2280-2283, binding of the carcinogen to nucleic acids was far greater than that to protein. Rat liver DNA bound ten times and rRNA twenty times more carcinogen than protein. There were also differences in the amount of carcinogen bound to rat liver nucleic acids compared to those of the hamster, the latter species binding lower amounts of the carcinogen. Rat liver DNA bound four times and rRNA ten times as much AFB1 6 h after carcinogen administration whereas liver protein bound AFB1 was similar for the two species. Not only was there a difference in the amount of AFB1 bound but whereas in the rat, liver nucleic acid bound carcinogen decayed with time, no such fall was seen in the hamster, this remaining at a low level throughout the 48-h time period studied. In contrast, reaction of the carcinogen with kidney macromolecules was similar for the two species. The much higher binding of AFB1 to nucleic acids than to protein might account for the potent carcinogenicity of this compound in the rat, particularly since liver protein binding does not differ between a susceptible and a resistant species. A further important factor in determining carcinogenic sensitivity may be the removal of nucleic acid bound radioactivity with time, a possible repair process.     

The effect of feeding 11-ketotestosterone on the food conversion efficiency and tissue protein and nucleic acid contents of juvenile carp, Cyprinus carpio L.

Juvenile common carp were fed 11-ketotestosterone for 60 days with the diet and the effect on food conversion efficiency, organ weights and protein and nucleic acids (RNA, DNA) content of the liver, kidney, brain and muscle were observed. Feeding of the steroid increased the food conversion efficiency of all the experimental groups studied as compared with controls. A decrease in weight of brain, liver and kidney in relation to body weight was noticed after 60 days of the hormone feeding. No change in the visceral weight was observed. These changes in relative weights of the organ were ameliorated 30 days after the withdrawal of the steroid from the food. The weight of the viscera decreased compared with the control weight during this time. Feeding of the hormone brought variable changes in the total proteins, RNA/DNA, protein/RNA and protein/DNA in all the organs studied. In addition to these findings, changes in the moisture, total lipid and ash contents of the muscle were also observed. The results are discussed in the light of existing knowledge of the effect of anabolic-androgenic steroids on the growth processes of different organisms.     

Comparison of the acetylation of proteins and nucleic acids

The possibility of acetylation of nucleic acids was examined. Although protein is actively acetylated with [1-(14)C]acetic acid in rat liver systems in vivo and in vitro and in a frog liver system in vivo, nucleic acids are not acetylated under these conditions; nucleic acids purified from these sources are without radioactivity. Requirements for acetylation in vitro of protein in rat liver are different from those in frog liver; GSH has no effect in the rat liver system and is inhibitory in the frog liver system. Among various acetylated proteins, proteins insoluble in 0.1m-sulphuric acid have the highest radioactivity.     

Antibiotic interaction with proteolytic enzymes]

The effect of penicillin, tetracycline, aminoglucozide antibiotics and streptomycin on BAEE-esterase activity of trypsin was studied. It was found that benzylpenicillin in amounts of 50, 100 and 300 mg, ampicillin in an amount of 25 mg, methicillin in an amount of 12 mg and tetracycline in an amount of 2.5 mg as calculated per 1 mg of trypsin had no effect in vitro on the esterase activity of the enzyme. Neomycin, kanamycin and streptomycin in amounts of 5, 10, 100 or 300 mg per 1 mg of trypsin catalyzed splitting of BAEE by trypsin. When the antibiotics were added to the bile, its esterase activity increased. Preliminary intramuscular administration of trypsin and kanamycin to the rats had no effect on the ampicillin levels in the blood serum and brain and did not affect the permeability of the hemato-encephalic barrier as compared to the use of trypsin alone.     

Inhibitory effects of orotate on precursor incorporation into nucleic acids.

The influence of orotic acid on the incorporation of precursors into nucleic acids was studied in mice and rats and in isolated cells. In vivo, orotate levels were modified by two diets which are known to increase the rate of pyrimidine nucleotide synthesis in rat liver. Of these diets, a 1% orotate diet had greater inhibitory effects than an arginine-deficient diet on the incorporation of [3H]orotate into RNA of mouse kidney than mouse liver. This contrasted with the situation in the rat where there was a greater effect in the liver than the kidney. The situation in the rat was more readily interpreted than in the mouse in terms of previously established effects of these diets on ribonucleotide pool sizes. However, studies using [3H]adenosine as a precursor for incorporation into RNA suggested that even in the mouse the effects of orotate were on pool sizes rather than an inhibitory effect on RNA synthesis. The incorporation of [3H]thymidine into DNA was inhibited by orotate to a similar degree in cultured HTC hepatoma cells and a line of rat liver epithelial cells. An effect on DNA synthesis rather than solely on pool sizes was suggested by the observation that the pool size of dTTP was not increased by 5 mM orotate under conditions in which there was a four-fold increase in the level of UTP in HTC cells. An inhibitory effect of orotate on DNA synthesis was further supported by an observation of decreased incorporation of [3H]deoxyadenosine into DNA and a lower rate of cellular proliferation.     

A direct effect of growth hormone on the incorporation of precursors into proteins and nucleic acids of perfused rat liver

1. The livers of rats were perfused in situ. When the amino acid concentration in the perfusing medium was that present in rat plasma, the addition of growth hormone to the medium stimulated the incorporation of labelled amino acids into liver protein only marginally and not to a statistically significant extent. When, however, the amino acid concentration was raised to three times that present in rat plasma, growth hormone significantly and substantially stimulated amino acid incorporation into protein within 30min. of perfusion of normal rat liver. 2. A significant effect of growth hormone on labelling of normal rat-liver protein was seen with concentrations not much greater than those reported to be present in rat plasma. 3. The labelling of nucleic acids of normal and hypophysectomized rat liver by [(3)H]orotic acid was enhanced by addition of growth hormone to the perfusing medium when normal concentrations of amino acids were used. 4. At elevated concentrations of amino acids, growth hormone stimulated labelling of nucleic acids of hypophysectomized rat liver at 30 and 60min. of perfusion. Under these conditions, nucleic acids of normal rats were labelled to about the same extent in control and hormone-treated livers at 30min. and, because of a fall in the radioactivity of the control livers, there was more labelled nucleic acids in growth-hormone-treated livers at 60min. than in the control livers. 5. Growth hormone, unlike insulin, had no inhibitory effect on the release of glucose by the perfused liver. 6. It is concluded that growth hormone can stimulate the incorporation of precursor into proteins and nucleic acids of liver directly and without the mediation of other organs or of insulin.     

Effect of hydroacridine derivatives on the sensitivity of polyresistant strains of Staphylococcus aureus and Escherichia coli to antibiotics]

Sensitivity of 4 clinical strains of Staph. aureus and E. coli to 13 hydroacridine derivatives and their combinations with antibiotics, such as benzylpenicillin, ampicillin, semi-synthetic penicillins, streptomycin, chloramphenicol, tetracycline, chlortetracycline, monomycin, oleandomycin and erythromycin was studied. The highest bacteriostatic effect was observed on the use of perhydroactidine derivatives with benzylpenicillin or ampicillin with respect to polyresistant penicillinase-producing strains of Staph. aureus, resistance of which to these antibiotics was decreased 250--1000 times. Under the effect of the above compounds the staphylococcal resistance to chloramphenicol, tetracycline, chlortetracycline, oleandomycine and erythromycin decreased 2--66 times. The combinations of hydroacridine with the antibiotics, except 10-amino-trans-syn-trans-perhydroacridine had no effect on the resistance of the E. coli strains. The results of the combined effect of the above substances were associated with their chemical nature, the bacterial type and possibly the character of the strain resistance.     

Lipid alterations in liver and kidney induced by normobaric hyperoxia: correlations with changes in microsomal membrane fluidity

The effects of normobaric hyperoxia on both microsomal membrane fluidity and mechanism of phospholipid synthesis in rabbit liver and kidney have been studied. Hyperoxia induces in both organs an impairment of de novo synthesis of glycerolipids which could be due to an inactivation of acyltransferase activities involved in the initial formation of phosphatidic acid. The ability to replace phospholipid fatty acids by reacylation mechanism decreases slightly in the hyperoxic kidney, while it does not change in the hyperoxic liver. Concerning the effect of high arterial pO2 on microsomal membrane fluidity, the hyperoxic liver shows a more fluid environment within the membrane core of microsomes; however, no difference was shown in that of microsomal membrane core of hyperoxic kidney. An insight into the lipid composition of microsomes indicates that liver microsomal membranes have lower cholesterol content and higher unsaturation degree of phospholipid fatty acids, whereas hyperoxic kidney microsomes become more saturated and did not show any difference in their cholesterol content. In both hyperoxic liver and kidney microsomes, phospholipid content decreases in agreement with the depression of phosphatidic acid biosynthesis. These results are discussed in relation to the values of microsomal membrane microviscosity obtained.     

Difference of the liver and kidney in glycine conjugation of ortho-substituted benzoic acids

The relative importance of the liver and kidney for glycine conjugation of ortho-substituted benzoic acids was investigated. Glycine conjugation of ortho-substituted benzoic acids was investigated in mouse liver and kidney mitochondria. The extent of glycine conjugation of benzoic acids with the halogen group decreased in the order F > Cl > Br > I. The conjugation of salicylic acid with glycine took place in only the kidney. 2-Methoxybenzoic acid exhibited no activity in the liver and kidney. The difference in glycine conjugation of ortho-substituted benzoic acids was observed between liver and kidney. The kidney was more active in glycine conjugation of ortho-substituted acids than the liver. In addition, the relationship between glycine conjugation and the chemical structure of ortho-substituted acids was examined in the liver and kidney. The size of the substituent had a far greater influence over glycine conjugation in the liver and kidney. Glycine conjugation was also dependent on the substituent electronegativity. It may be important that the substrates undergoing glycine conjugation contain a flat region coplanar to the carboxylate group.     

The effects of chlorphentermine and phentermine on certain metabolic parameters associated with development of rat kidney and liver.

Daily oral administration of the anorexigenic agents chlorphentermine or phentermine (60 mg/kg) to rats for either 1, 3, 5 or 7 days resulted in a significant fall in the incorporation of [¹⁴C]thymidine into renal and hepatic DNA throughout the course of the experiment. Although 24 h after treatment with either drug there was no dramatic change in the incorporation of [¹⁴C]orotic acid into liver RNA, a statistically significant reduction was noted after 3, 5 and 7 days. In rat kidney, the incorporation of [¹⁴C]orotic acid into RNA was only significantly depressed by chlorphentermine at 5 days and by phentermine at 3 days. In general, treatment with either anorexigenic agent tended to significantly lower or not affect the endogenous concentrations of renal and hepatic putrescine, spermidine and spermine. The chlorphentermine-induced decrease in liver and kidney nucleic acid synthesis was accompanied by depression in the levels of cyclic AMP in both tissues as well as a reduction in the activity of adenylate cyclase in renal tissue. In contrast, chlorphentermine produced a rise in hepatic adenylate cyclase at 5 days followed by a return to control values after 7 days. The phentermine-induced alterations in nucleic acid metabolism appeared generally to occur independent of any changes in the adenylate cyclase-cyclic AMP system of renal and hepatic tissues. In view of the fact that nucleic acids, polyamines and cyclic AMP constitute integral components of the growth process, our data suggest that chlorphentermine and phentermine interfere with certain biochemical parameters associated with the development of kidney and liver.     

Comparative cytophotometric analysis of the nucleic acid content in the cardiomyocytes of normal rats and following experimental infarct

The cytophotometrical investigation of gallocyanine-chrome alum stained cardiac muscle cells allows to ascertain that a mean content of the nucleic acids calculated for a single nucleus is essentially higher in the left ventricle myocytes in comparison with the left auricle cells of healthy adult rats. These values in 1-, 2- and 3-nuclear cells of the ventricle are, respectively, 21.3, 19.3, and 18.0, and 14.1, 13.7, 13.5 of arbitrary units (a. u.) in the auricle cells. A difference in cytoplasmic RNA contents of the same cells is more significant, these values are 65.7, 116.4, and 158.9 a. u. in ventricle myocytes, and 33.4, 60.8 and 95.2 a. u. in auricle cells. The nucleic acids content in the nuclei and RNA content in the cytoplasm increase with the development of proliferation in myocytes after experimental myocardial infarction. A relative increase in the nucleic acids content in the nuclei of the same cell types reaches 50, 24, and 10% 11 days after infarction and 56, 38, and 45% 31 days after infarction. A relative increase in cytoplasmic RNA of the same cells reaches, respectively, 52, 17, and 25%, and 70, 57, and 53% 11 and 31 days after infarction. These findings evidence on the greatest synthetic activity of the single-nuclear auricle muscle cells in the process of heart restoration after infarction.