[Superoxide dismutase and catalase activities in carotenoid-synthesizing fungi Blakeslea trispora and Neurospora crassa under the oxidative stress].

The addition of menadione into the medium during cultivation of Neurospora crassa in the dark activated its constitutive superoxide dismutase. Exposure to light not only activated superoxide dismutase and catalase, but also increased the content of neurosporaxanthin. Superoxide dismutase activity in the mixed (+/-) mycelium of Blakeslea trispora synthesizing beta-carotene in the dark was much lower than that in Neurospora crassa.

[Biosynthesis and use of coproporphyrins and uroporphyrins and their metal complexes in immune analysis and diagnostic methods].

Methods of synthesis of coproporphyrin and uroporphyrin by using bacteria of the genus Arthrobacter are proposed. Metal complexes of coproporphyrin and uroporphyrin with Pt, Pd, and Zn were synthesized. Their structures were identified by spectrophotometry, IR spectrometry, 1H-NMR, mass spectrometry, and HPLC.

Free radical lipid peroxidation inhibits enzymatic conversion of beta-carotene into vitamin A.

Free radical oxidation of arachidonic acid with soybean lipoxygenase was accompanied by inhibition of retinal synthesis from beta-carotene catalyzed by enzyme preparation from rabbit intestinal mucosa. Lipoxygenase inhibitor salicylhydroxamic acid and antioxidants suppressing free radical reactions (ethyl gallate, alpha-tocopherol, astaxanthine, and quercetin) promoted conversion of beta-carotene into retinal catalyzed by beta-carotene-15,15'-dioxygenase. These results indicate that lipoperoxides and/or products of their homolysis attenuate enzymatic conversion of beta-carotene and confirm the important role of natural antioxidants in the maintenance of stable vitamin A content in mammals.

[Features of the elemental composition of medicinal plants, synthesizing phenolic compounds].

A total of 52 species of medicinal plants capable of synthesizing phenolic compounds were subjected to mass-scale screening for 24 chemical elements. The screening was performed by atomic absorption spectrometry in combination with spectrophotometric detection. The plant species tested were found to accumulate groups of two to ten chemical elements (Fe, Cr, Cu, Co, Mn, etc.

[Conversion of beta-carotene and some beta-apocarotinoids under the effect of substances from the intestinal mucosa].

Products of cleavage of beta-carotene and certain apocarotenoids (beta-apo-4', 8', 10', and 12'-carotenols and citranaxanthol) were studied, and the dynamics of their generation in the presence of an enzyme preparation isolated from rabbit intestinal mucosa was determined. The data suggest that metabolism of beta-apocarotenols involves the production of retinal and beta-apo-14'-carotenal mediated by enzymes different from beta-carotene-15,15'-dioxygenase, which converts beta-carotene to retinal. A scheme of metabolic conversion of beta-carotene is discussed.

Some natural and synthetic antioxidants as stabilizers of beta-carotene conversion into vitamin A.

The effect of antioxidants (vitamins C and E, quercetin, probucol, butylated hydroxytoluene) on the oxidation of beta-carotene and its conversion into retinal under the influence of beta-carotene 15,15'- dioxygenase (CDO) from rat intestinal mucosa was studied. The activity of CDO decreased in the presence of oxidants. Antioxidants protected both the substrate and the enzyme.

[Tetrapyrroles: diversity, biosynthesis, biotechnology].

Various aspects of metabolism and biotechnology of tetrapyrroles are reviewed. Structures and properties of newly discovered tetrapyrrole pigments, biosynthesis of most important functional tetrapyrroles (hemes, chlorophylls, corrinoids, siroheme, and methanogenesis factor F430), and biotechnological methods of production of porphyrins and corrinoids are discussed. 5-Aminolevulinic acid is shown to be a promising anticancer preparation.

[Radiation-protective effect of S-methylmethionine (vitamin U)].

S-Methylmethionine had moderate radioprotective activity, the efficiency of radioprotection was 15-30%, the value of dose decrease coefficient-1.2. Biological effect of S-methylmethionine was probably provided by its ability to decrease the level of lipid peroxidation and inhibit monoamine oxidase activity.

[Monoamine oxidase activity in rat liver in vitamin B12 deficiency].

Changes in the activity of monoamine oxidase (MAO-B) in liver homogenates and mitochondria from normal and vitamin B12-deficient rats have been studied in various functional states of the mitochondria. Preincubation of liver preparation at 32 degrees C increased the MAO affinity for benzylamine in samples of normal (but not vitamin B12-deficient rats). Succinate added to the incubation medium decreased Km and increased Vmax in both normal and vitamin B12-deficient animals.

[Change in tryptamine metabolism in vitamin B12 deficiency].

The metabolism of tryptamine was studied in rats in health and in vitamin B12 deficiency. Excretion of cobalamin with urine before and after loading with tryptamine was studied. Daily excretion of tryptamine with urine in vitamin B12-deficient animals was normal or slightly increased.

[The character of the interaction of beta-carotene-15,15'-dioxygenase from rabbit small intestine with lycopene, 15,15'-dehydro-beta-carotene, lutein, and astaxanthine].

Interaction of rabbit small intestine mucosa beta-carotene 15,15'-dioxygenase with lycopene, 15,15'-dehydro-beta-carotene, lutein and astaxanthine is unaccompanied by the formation of products of enzymatic cleavage of the central double bond of these carotenoid molecules. Apo-carotenoids of lutein and lycopene are formed by nonenzymatic oxidation. Lycopene and 15,15'-dehydro-beta-carotene competitively inhibit the enzymatic oxidation of beta-carotene.

[Metabolites of the propionate pathway as regulators of fatty and dicarboxylic acid oxidation in liver mitochondria].

The functioning of the propionate pathway of oxidation substrate metabolism in the norm and under vitamin B12 deficiency has been studied. This pathway has been shown to play an important role in oxidative processes occurring in normal organisms, for its inhibition in B12-deficient animals is associated with a reduction of respiration as well as with noticeable decreases in palmitoylcarnitine and succinate oxidation rates and oxidation phosphorylation coupling. Succinate, the end product of the propionate pathway, normalizes the respiration and restores the rate of palmitoylcarnitine oxidation in B12-deficient animals, which is suggestive of its crucial role in the propionate pathway.

[Properties of beta-carotene-15,15'-dioxygenase, stabilized during purification with lutein and dithiothreitol].

Preparations of beta-carotene 15,15'-dioxygenase (EC 1.13.11.

[Enzymatic conversion of torulene and torularhodine into retinal].

The enzymatic conversion of torulene to retinal is demonstrated in in vitro tests using beta-carotene 15,15'-dioxygenase (EC 1.13.11.

[Effect of propionate pathway metabolites on the oxidative activity of liver mitochondria under normal conditions and in vitamin B12 deficiency].

We performed a comparative investigation in vivo and in vitro of the propionate and methylmalonate effect on oxidative activity of liver mitochondria in control and vitamin B12-deficient rats and found that efficiency of the effects were less pronounced in vitamin B12-deficient rats. It is also shown that the rates of respiration and phosphorylation decreased in liver mitochondria of vitamin B12-deficient rats.

[Stabilization and protection of an enzymatic system, participating in the transformation of beta-carotene into retinal, during its isolation].

The authors studied the effect of dithiothreitol (DTT), carotenoids and protease inhibitors on stabilization and protection of the enzyme catalysing the conversion of beta-carotene into retinal during the enzyme isolation from the rabbit small intestine. The addition of 1 mM DTT into the homogenization mixture increased the activity of the enzyme 5 times compared with control. The additional introduction of 0.

[Metabolism of S-methylmethionine (vitamin U) in animals].

Metabolism of S-methylmethionine (vitamin U) has been studied in rats. Biotransformation of this compound actively proceeds in the liver, kidneys, and digestive tract. Metabolism of S-methylmethionine in the liver and kidneys was found to proceed both via methylation of homocysteine with the formation of methionine and via enzymatic hydrolysis to dimethylsulfide and homoserine.

[The effect of metabolites of the propionate pathway on the oxidative activity of liver mitochondria].

Methylmalonate and propionate, the major metabolites of the propionate pathway of fatty and amino acid metabolism used at 1-4 mM cause selective inhibition of succinate and palmitoyl carnitine oxidation in liver mitochondria. Methylmalonate is more specific towards succinate, whereas propionate--towards palmitoyl carnitine oxidation. Methylmalonate is transported to mitochondria at a high rate with no effect on succinate transport.

[Experience with the use of sodium oxybutyrate electrophoresis by sinusoidal modulated currents in the combined treatment of patients with stable stenocardia].

Stable angina pectoris (functional class I, II, III) was treated by SHE with sinusoidal modulated current plus sodium chloride baths against placebo plus balneotherapy. Macro- and microcirculatory analysis of cardiovascular function and clinical evidence indicated that the addition of the electrophoresis raises the efficacy of the treatment 2-3-fold. The use of the combination proposed is advocated in prevention and treatment of stable angina pectoris.

[The effect of methylation on the carnitine synthesis].

The effect of vitamin B12, its analogs and donors of methyl groups on the coupling of methylation and carnitine accumulation in rats was studied. Biological active forms of vitamin B12 (methylcobalamine, cyanocobalamine, hydroxycobalamine) are shown to stimulate the carnitine synthesis in liver. The donor of methyl groups S-methylmethionine, also has a positive effect.

[Fluorescent immunoassay of thyroxine in blood serum].

A method of solid-phase fluoroimmunoassay of thyroxine (T4) on polystyrene 96-microtiter plates using coproporphyrin III-labeled antibodies was developed; 0.02 ml of blood serum without preliminary treatment was required. Thimerosal was added to lessen the T4-binding effect of the serum on the results of T4-binding effect of the serum on the results of the immunoassay.

[Effect of vitamin B12 on carnitine synthesis in the body of rats].

The effect of vitamin B12 on carnitine metabolism in rats has been investigated. The injection of coenzyme B12 into male rats has been shown to result in the increase of carnitine in liver. The dynamics of this process and its dependence on the age of rats have been studied.