Bacillus mesentericus was found to assimilate nucleic acids as a source of nitrogen and phosphorus. Nucleic acids added to the medium as a source of nitrogen or phosphorus stimulated synthesis of ribonuclease. When washed bacterial cells were incubated for a short period of time in a fresh nutrient medium containing RNA, synthesis of RNAase was also induced. Synthesis of the enzyme was inhibited by high concentrations of chloramphenicol and actinomycin D, and stimulated by low concentrations of actinomycin D. Therefore, alkaline RNAase is an inducible enzyme which participates in the nutrition processes of bacteria.

Acetic acid was found to repress cholinesterase synthesis in the cells of Arthrobacter simplex var. cholinesterasus even at very low concentrations (0.1%). The repression is very stable. It is not eliminated by glucose or an organic acid of the Krebs cycle being added to the medium with acetic acid. The combination of acetic and butyric acids decreases the repression but does not eliminate it. The kinetics of cholinesterase synthesis was different in the cells grown on the medium with acetic acid and the cells cultivated on the medium with acetic acid and glucose, then washed and transferred to a fresh growth medium with glucose and acetylcholine as the sources of carbon.

beta-Lactamases of Proteus and their role in the mechanism of the microbe resistance to penicillins and ceporin were studied. It was found that the beta-lactamase of Proteus had low activity and were produced by both beta-lactamide resistant and sensitive clinical strains of Proteus. The resistant cultures of Proteus produced enzymes more frequently (3.4--5 times) than the sensitive ones. The synthesis of beta-lactamase in the clinical Proteus strains was inducable. The high induction coefficient was achieved only in the presence of high concentrations of the inductor. No significant dependence of the culture sensitivity level of ampicillin and ceporin on the induction level was observed. The most significant part of the constitutive enzyme in Proteus was intracellular, while that of the inducable enzyme was extracellular. No correlative dependence between the culture resistance levels to penicillins and ceporin and the enzyme activity was noted. The beta-lactamase activity was not found in the transconjugants with the in vitro acquired R-factor controlling the ampicillin and ceporin resistance, as well as in the resistant mutants selected on the media with increasing concentrations of the above antibiotics. Induction of beta-lactamase synthesis was not found in these strains either. The ability of Proteus to synthesize beta-lactamase can be lost on the strain storage under laboratory conditions which was not always accompanied by reduction of the culture sensitivity to ampicillin and ceporin. The enzymatic destruction of beta-lactamides was not the main mechanism of Proteus resistance to the above antibiotics.

The production of exolipase was studied in various Pseudomonas species, most of which did not possess the lipolytic activity in the conditions of the experiment, whereas in some strains this activity was rather high. The highest activity was displayed by the Pseudomonas fluorescens 533 strain and its mutant obtained upon UV irradiation. Lipase biosynthesis depended on the composition of a growth medium, the highest lipolytic activity being found on media with a high content of complex organic substances. No correlation was established between the growth and the lipolytic activity. A lipase preparation was isolated from the Ps. fluorescens 533-5b mutant, partly purified by precipitation with ammonium sulphate and dialysis, and its response to the action of inhibitors and heavy metal ions was studied. The enzyme activity was inhibited by these ions, and stimulated by Mg2+ ions. EDTA was found to be the strongest among all the inhibitors tested.

The induction influence from low doses of phenobarbital introduced for 3 days (10, 10 and 20 mg/kg) on the detoxication rate of hexanal (100 mg/kg) in mongrel rats of different sexes and age was studied. Investigations included measurements of the protein, phospholipids and glycogen content in the liver and the use of continued lateral position time test. A three-day phenobarbital pre-treatment speeded up the hexenal detoxication in rats of all the age groups except the oldest ones (26--32 months). The acceleration as against controls was more spectacular in younger rats and sexually mature female rats (by comparison with sexually mature male rats). As contrasted to controls, a three-day administration of phenobarbital produced in test animals a rise of protein, phospholipids and glycogen content in the liver.

The activity of enzymes of creatin biosynthesis in the rat liver and kidneys has been studied during the postnatal development. The activity of transamidinase of kidneys (E.C. 2.1.4.1.) increases gradually and linearly up to the 20th day after birth, then decreases on the 12th--25th days and increases again up to the level characteristic of the adult organism. The activity of guanidine acetate-N-methyl transferase (E.C. 2.1.1.2.) is rather high during the first days of postnatal development, then decreases and from the 15th day on increases again attaining the maximal level by the 23rd--25th day. The second period of the increase in the enzyme activity begins on the 29th--30th day of postnatal development. The results obtained suggest that the sharp increase of activity of guanidine acetate-N-methyl transferase of the rat liver during the early postnatal development is realized with the participation of cyclic 3',5'-AMP which appears to mediate the glucagon action.

The influence of cortisole injections and stress ("handling") in the early ontogenesis (during the first 9 or 16 days of life) on the process of thyrosine aminotransferase induction by cortisol in the adult rats has been studied. It was shown that both the injection of the hormone in the young rats and "handling" led to the manifested trace effects: (1) stable increase of thyrosine aminotransferase activity in the liver of adult (5-6 months) rats and (2) appearance of peculiar tolerance to cortisol in the form of decrease in the ability of cells to induce thyrosine aminotransferase in response to the hormone injection. The data obtained suggest that the sensitive period of postnatal ontogenesis when cortisol or "handling" exert such a stable effect is limited by the 3rd and 9th days after birth. The causes of such "biochemical imprinting" are considered with respect to the increased sensitivity of the genetical system of cells-targets to the transcription inducers during the early postnatal development.

The sensitivity of induced synthesis of exocellular protease to catabolyte repression was studied in Serratia marcescens growing on media containing inductors, viz. leucine and albumin. A lower sensitivity of the leucine-induced synthesis of the enzyme to glucose as compared to that induced by albumin seems to be caused by the penetration of leucine into the cell prior to the appearance in the medium of organic acids, possible inhibitors of its transport, whereas on the medium containing albumin, leucine appears only after hydrolysis of the protein by the "basal" enzyme.

Acitivity of tyrosine-alpha-ketoglutarate transaminase and induction of the enzyme by hydro cortisone were studied in rat liver tissue after partial hepatectomy and intoxication with CCl4 Administration of the hormone increased the enzymatic activity within 72 hrs after treatment with CCl4 but did not affect its value within 8 and 24 hrs. Activation of the enzyme by hydrocortisone correlated with the increased enzymatic activity observed within 20 hrs after partial hepatectomy. Possible mechanisms for activation of the enzyme, caused by endo- and exogenous factors, are discussed.

A possibility to increase 7alpha-hydroxylation of 4-14C-cholesterol was studied in vitro, using microsomal enzymes from rat liver tissue, under effect of such inductors of these enzymes as 5-ethyl-5-phenyl barbituric acid (phenobarbital), pregnenolone-16alpha-carbonitrile, 16-dehydropregnenolone, 3-acetate-16alpha-isothiocyanogen pregnenolone. These inductors were administered per os within 5 days as an aqueous suspension, stabilized with Tween 80 at a dose 50 mg/kg daily; ethyl ester alpha-(p-chlorophenhydroxy)-isobutyric acid (klofibrate "Miskleron*) was administered at a dose of 150 mg/kg daily within 5 days. All the inductors studied increased the activity of cholesterol 7alpha-hydroxylase: pregnenolone-16alpha-carbonitrile--by 50%, 16-dehydropregnenolone--by 80%, 3-acetate-16alpha-isthiocyanogen pregnenolone--by 110% and phenobarbital--by 200%. Klofibrate did not affect the intensity of the cholesterol hydroxylation.

Administration of phenobarbital to male-rats for 4 days induced the appearance of P-450 cytochrome in the liver and intensified the activity of the hydroxylase system, more specifically with respect to hexobarbital than to amidopyrine. The cataleptic effect of chlorpromazine was then running low. A 4-day long administration of chlorpromazine failed to increase the P-450 cytochrome content, but did change the hydroxylating activity of the microsomes in favour of the amidopyrine metabolism. With joint introduction of chlorpromazine and phenobarbital the intensity of the amidopyrine hydroxylation increased to a greater extent.

An anti-influenza preparation, rimantadine (alpha-methyl-1-adamantane methylamine hydrochloride) at concentrations of 10--25 mkg/ml depresses the RNA-dependent RNA polymerase induction in a culture of cells infected with influenza virus (fowl plague virus). The inhibitory effect is also observed 2 hours following cell infection. In vitro studies have demonstrated that rimantadine has no effect on the activity of virus-induced RNA-dependent RNA polymerase, as well as on that of RNA-dependent RNA polymerase associated with virus particles.

The activity of glutamate dehydrogenase (EC 1.41.1.3) is studied in homogenates and subcellular fractions of five limbic structures: regio superior, regio inferior of hippocampus, fascia dentata, septum and corpora mamillaria. The lowest activity of the enzyme is found in regio superior of hippocampus. 80% of the total enzyme activity of primary fractions is found in "crude" mitochondria. After centrifugation of the latter within the linear sucrose density gradient the distribution of the enzume activity is similar for different structures and the highest activity is found in the region of sucrose molarity from 1.44 up to 1.50 M which corresponds to the mitochondria distribution region. 50% of the total found activity is in the fraction enriched by mitochondria, 30% is in the fraction enriched by nerve endings with the high activity of glutamate decarboxylase. It was found for different fractions that 1 mM of ADF with 0.2 mM NAD-H+ produces about 10-fold increase in the enzyme activity. Pyridoxal-5'-phosphate inhibits the enzyme from inactivation. The results are discussed in connection with the possible role of pyridoxal-5'-phosphate in regulation of the glutamate dehydrogenase activity in vivo.

The study of 50 clinical strains of Ps. aeruginosa revealed their high resistance to benzylpenicillin, ampicillin, oxacillin, streptomycin and kanamycin with a tendency to polyresistance. The same strains were highly sensitive to gentamycin and polymyxin. The strains produced constitutive beta-lactamase in small amounts. The enzyme synthesis in Ps. aeruginosa was induced by benzylpenicillin. Still high concentrations of it were required for the induction. The maximum induction of beta-lactamase synthesis was observed by the 6th hour of the inductor addition. The maximum induction level was observed 4 hours after addition of benzylpenicillin. The level of induction of beta-lactamase synthesis in the strains ranged within 5-93. A significant part of the enzyme was liberated from the cells during induction. Interaction between the induction level of beta-lactamase synthesis and resistance of Ps. aeruginosa to penicillins was found.