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Applied Biochemistry and Microbiology (v.39, #2)
Multiple Functions of Corrinoids in Prokaryote Biology by E. P. Ryzhkova (Jordan) (pp. 115-140).
Data on the more than 30 metabolic processes and biochemical reactions involving corrinoids that have been described in prokaryotes thus far are reviewed. These pathways (central or special, catabolic or anabolic) are inherent in bacteria and archebacteria of diverse phylogenetic lineage, comprising several physiological groups. Particular emphasis is placed on the role of corrinoid-dependent transmethylation in acetogenesis and methanogenesis and on the contribution of adenosylcobalamin to DNA metabolism.
Kinetics of Catalase Inactivation Induced by Ultrasonic Cavitation by M. V. Potapovich; A. N. Eremin; D. I. Metelitza (pp. 140-146).
Kinetic patterns of sonication-induced inactivation of bovine liver catalase (CAT) were studied in buffer solutions (pH 4.0–11.0) within the temperature range from 36 to 55oС. Solutions of CAT were exposed to LF (20.8 kHz) ultrasound (specific power, 48–62 W/cm2). The kinetics of CAT inactivation was characterized by effective first-order rate constants (s–1) of total inactivation (k in), thermal inactivation (*k in), and ultrasonic inactivation (k in(us)). In all cases, the following inequality was valid: k in > *k in. The value of k in(us) increased with the ultrasound power (range, 48–62 W/cm2) and exhibited a strong dependence on the pH of the medium. On increasing initial concentration of CAT (0.4–4.0 nM), k in(us) decreased. The three rate constants were minimum within the range pH 6.5–8.0; their values increased considerably at pH < 6.0 and pH > 9.0. At 36–55oС, the temperature dependence of k in(us) was characterized by an activation energy (E act) of 19.7 kcal/mol, whereas the value of E act for CAT thermoinactivation was equal to 44.2 kcal/mol. Bovine and human serum albumins (BSA and HSA, respectively) inhibited sonication-induced CAT inactivation; complete prevention was observed at concentrations above 2.5 μg/ml. Dimethyl formamide (DMFA), a scavenger of hydroxyl radicals (НO • ), prevented sonication-induced CAT inactivation at 10% (k in and *k in increased with the content of DMFA at concentrations in excess of 3%). The results obtained indicate that free radicals generated in the field of ultrasonic cavitation play a decisive role in the inactivation of CAT, which takes place when its solutions are exposed to low-frequency ultrasound. However, the efficiency of CAT inactivation by the radicals is determined by (1) the degree of association between the enzyme molecules in the reaction medium and (2) the composition thereof.
Induction of the Synthesis of Endo-1,4-β-xylanase and β-Galactosidase in Original and Recombinant Strains of the Fungus Penicillium canescens by E. A. Vavilova; Yu. P. Vinetskii (pp. 147-151).
The induction of synthesis of the secreted enzymes endo-1,4-β-xylanase (EC 3.2.1.8) and β-galactosidase (EC 3.2.1.23) in original and recombinant Penicillium canescens strains has been studied. In all producer strains, the synthesis of these enzymes was induced by arabinose and its metabolite arabitol. The two enzymes differed in the concentration of arabinose required for induction: the synthesis of β-galactosidase was most pronounced at 1 mM, whereas maximum synthesis of endo-1,4-β-xylanase was observed at 5–10 mM. An increase in the number of endo-1,4-β-xylanase copies in the high-copy-number strain of the fungus suppressed the synthesis of β-galactosidase; the synthesis of endo-1,4-β-xylanase in the high-copy-number recombinant producing β-galactosidase was affected to a lesser extent. The amount of enzymes synthesized did not depend on the saccharide used as the sole source of carbon for growing the mycelium prior to its transfer to the inducer-containing medium.
Identification of a New Steroid-Transforming Strain of Mycobacteria as Mycobacterium neoaurum by N. E. Voishvillo; V. A. Andryushina; T. S. Savinova; T. S. Stytsenko; N. A. Vasil'eva; T. P. Turova; T. V. Kolganova; K. G. Skryabin (pp. 152-157).
The ability to utilize sterols as a sole source of carbon was studied in 80 strains and consortia of hydrocarbon-oxidizing bacteria. One of the strains, which efficiently transformed both individual sterols and their mixtures, was identified as Mycobacterium neoaurum based on the analysis of the sequence of the 16S rRNA gene.
Regulation of Acetate Metabolism in a Strain of Acinetobacter sp. Growing on Ethanol by T. P. Pirog; Yu. V. Kuz'minskaya (pp. 158-165).
Ethanol metabolism in Acinetobacter sp. is shown to be limited by the rate of acetate assimilation, a reaction catalyzed by acetyl-CoA synthetase (EC 6.2.1.1). Effects of ions (sodium, potassium, and magnesium), by-products of ethanol and acetaldehyde oxidation (NADH and NADPH), and pantothenic acid on this enzyme are studied (sodium, NADH, and NADPH inhibit acetyl-CoA synthetase; pantothenic acid, potassium, and magnesium act as enzyme activators). Conditions of culturing were developed under which ethanol, acetaldehyde, and acetate in Acinetobacter cells were oxidized at the same rates, producing a threefold increase in the activity of acetyl-CoA synthetase in the cell-free extract. The results of studies of acetyl-CoA synthetase regulation in a mutant strain of Acinetobacter sp., which is incapable of forming exopolysaccharides, provide a basis for refining the technology of ethapolan production involving the use of C2 substrates.
Kinetic Parameters of a Culture of the Hydrogen-Oxidizing Bacterium Ralstonia eutrophaGrown under Conditions Favoring Polyhydroxybutyrate Biosynthesis by T. G. Volova; N. A. Voinov (pp. 166-170).
Kinetic parameters of a culture of the hydrogen-oxidizing bacterium Ralstonia eutrophagrown on a gas substrate under conditions favoring autotrophic biosynthesis of polyhydroxybutyrate were studied. The following parameters, making it possible to control and optimize the process in industrial situations, were determined: specific rate of substrate consumption, physical properties of the culture medium, and coefficients of heat emission and mass transfer.
Effect of Toxic Concentrations of 2,4,6-Trinitrotoluene on the Physical Properties and Morphology of Bacillus subtilis SK1 Cells by B. M. Kurinenko; G. Yu. Yakovleva; N. A. Denivarova; Yu. V. Abreimova (pp. 171-174).
It has been demonstrated for the first time that the toxic effect of 2,4,6-trinitrotoluene on the gram-positive strain Bacillus subtilis SK1 is accompanied by a decrease in the cell size and an increase in the refraction index (i.e., density) and temperature resistance of the culture. These data suggest that determination of kinetic parameters of bacteria growing under conditions of toxic stress on the basis of optical density measurements may result in erroneous conclusions.
Reversed-Phase High-Performance Liquid Chromatography of Products of Microbiological Degradation of Toluene by N. F. Zelenkova; M. U. Arinbasarov (pp. 175-177).
Conditions have been selected for reversed-phase high-performance liquid chromatographic assay of intermediate products formed in the course of utilization of toluene by Pseudomonas putida. The composition of products indicates that degradation of toluene by strain BS590-P proceeds primarily through the formation of benzoate and catechol. This is followed by degradation of catechol via ortho-cleavage. In strain BS3701-P, toluene oxidation involves both the side chain and the aromatic ring.
Extracellular Protein Metabolite of Luteococcus japonicus subsp. casei Reactivates Cells Subjected to Oxidative Stress by L. I. Vorob'eva; E. Yu. Khodzhaev; G. M. Ponomareva; A. L. Bryukhanov (pp. 178-182).
A protein exometabolite isolated from the culture liquid of Luteococcus japonicus subsp. casei reactivates the cells of this microorganism following H2O2- or paraquat-induced oxidative stress. The resistance of L. casei cells to these oxidizers is accounted for by the high activity of superoxide dismutase and catalase. The effect of the protein exometabolite is universal, in that it reactivates the cells after UV irradiation, heating, or oxidative stress. However, cells subjected to oxidative stress are significantly less susceptible to the reactivating effect as compared to their UV-irradiated or heated counterparts. Possible causes of these differences are discussed.
Dependence of the Composition of the Avermectin Complex of Streptomyces avermitilis on the Glucose Content in the Medium by V. A. Mironov; A. V. Sergeeva; A. V. Gavrilina; V. N. Danilenko (pp. 183-187).
The effects of the glucose concentration in the medium and O-methyl-L-threonine resistance on the ratio of components of the avermectin complex produced by Streptomyces avermitilishave been studied. Glucose deficiency increases the ratio of components A and ain the complex, while decreasing that of components 1. A mutation that renders the microorganisms resistant to O-methyl-L-threonine (an analogue of isoleucine) increases the ratio of components a in the complex, while decreasing that of components 1. The distribution of aand b in fractions 1and 2 remains constant: the values of the ratio a/b in the fractions amount, respectively, to 1 : 1 and 2 : 1. The relation of the variations in the composition of the avermectin complex to changes in the carbohydrate metabolism of the producer stain, underlain by availability of the source of carbon, is discussed.
Effect of Various Sources of Nitrogen and Carbon on the Biosynthesis of Proteolytic Enzymes in a Culture of Aspergillus awamori 21/96 by R. K. Blieva; Zh. E. Safuani; Zh. A. Iskakbaeva (pp. 188-191).
Effects of various conditions of nitrogen and carbon nutrition on the biosynthesis of proteolytic enzymes in a selected culture of Aspergillus awamori 21/96 were studied. This strain was shown to produce proteolytic enzymes constitutively. In the presence of mineral sources of nitrogen, the synthesis of the enzymes under study was not induced by proteinaceous substrates. Optimum conditions of the enzyme biosynthesis were achieved with casein as a source of nitrogen and starch or dulcitol as a source of carbon (which increased the production of the enzymes by 1.7 and 8 times, respectively). When the cells were grown on starch, their specific activity exceeded control levels by 18 times.
Occurrence of Indole Alkaloids among Secondary Metabolites of Soil Aspergillus Spp. by N. G. Vinokurova; I. I. Khmel'nitskaya; B. P. Baskunov; M. U. Arinbasarov (pp. 192-196).
The occurrence of indole alkaloids among secondary fungal metabolites was studied in species of the genus Aspergillus, isolated from soils that were sampled in various regions of Russia (a total of 102 isolates of the species A. niger, A. phoenicis, A. fumigatus, A. flavus, A. versicolor, A. ustus, A. clavatus, and A. ochraceus). Clavine alkaloids were represented by fumigaclavine B, which was formed by A. fumigatus. α-Cyclopiazonic acid was formed by isolates of A. fumigatus, A. flavus, A. versicolor, A. phoenicis, and A. clavatus. The occurrence of indole-containing diketopiperazine alkaloids was documented for isolates of A. flavus, A. fumigatus, A. clavatus, and A. ochraceus. No indole-containing metabolites were found among the metabolites of A. ustus or A. niger.
Production of Fumonisins by Fusarium moniliforme Strains Isolated from Corn Grain by L. S. L'vova; I. B. Sedova; O. I. Kizlenko; V. A. Tutel'yan (pp. 197-201).
Fusarium moniliforme is the predominant fusarium species in the grain mycoflora of corn grown in the northern Caucasus, accounting for 95% of fusarium isolates. Eighty-five Fusarium moniliforme strains were grown on a grain substrate and checked for the presence of fumonisins (B1 + B2 + B3) by indirect solid-phase enzyme immunoassay. All strains were capable of producing fumonisins (0.95 to 32 500 mg/kg). Strains sampled in Krasnodar krai produced the highest fumonisin levels (averaging 5490 mg/kg). Fusarium moniliforme strains were subdivided into three morphological types. The types differed significantly in the rate of fumonisin production. Strains belonging to the mycelial type (I) produced the greatest amount of the toxin, and those of the pionnotal type (III) were the least active. Strains of the sporodochial type (II) had an intermediate activity. The mean levels of fumonisin accumulation (mg per kg) for each type were I, 7460; II, 1150; and III, 227.
Products of Spontaneous Conjugation of Aflatoxins with Bovine Serum Albumin: Immunochemical Properties by A. A. Burkin; G. P. Kononenko; N. A. Soboleva (pp. 202-209).
Products of spontaneous conjugation of aflatoxins B1, G1, and G2 with bovine serum albumin (BSA) were shown to interact with antibodies against aflatoxins. Solid-phase BSA conjugates inhibited the binding of aflatoxins by antiaflatoxin antibodies. Antisera against BSA–B1, BSA–G1, and BSA–G2 were obtained and their specificity determined. The mechanisms of spontaneous binding of aflatoxins by proteins are discussed.
Effects of Ambiol and 2-Chlorethylphosphonic Acid on the Content of Phytohormones in Potato Leaves and Tubers by I. G. Kirillova; A. S. Evsyunina; T. I. Puzina; N. P. Korableva (pp. 210-214).
The effects of the antioxidant Ambiol and 2-chlorethylphosphonic acid (2-CEPA) on individual concentrations and concentration ratios of phytohormones, photosynthesis and photophosphorylation rates, sucrose and starch content in tubers, and plant productivity were studied in potato (Solanum tuberosum L). Ambiol increased the ratio of indoleacetic acid (IAA) to abscisic acid (ABA), IAA/ABA, and that of zeatin (Z) and zeatin riboside (ZR) to ABA, (Z + ZR)/ABA. These effects were underlain by an increase in the content of auxins and cytokinins and a decrease in ABA. Unlike Ambiol, 2-CEPA increased the level of ABA, the effect being the most pronounced in the tubers. Ambiol increased the rates of photosynthesis and noncyclic photophosphorylation in chloroplasts isolated from potato leaves. The relation of this phenomenon to auxin and cytokinin accumulation, as well as Ambiol- and 2-CEPA-induced changes in the hormonal balance of potato tubers, carbon metabolism, and plant productivity, is discussed.
Binding of Aliphatic Aldehydes by Cornstarch Polysaccharides by M. B. Terenina; N. I. Krikunova; I. B. Medvedeva; T. A. Misharina (pp. 215-220).
Binding by cryotextured cornstarch of individual aliphatic aldehydes (C6–C10; saturated or unsaturated) and their mixtures from aqueous solutions has been studied using capillary gas chromatography. The amount of compounds sorbed by the cryotextures depended linearly on the concentration of aldehydes in the original gel. The majority of the compounds under study were bound irreversibly. Aldehydes with low molecular weight were better sorbed by the cryotextures than by granules of native cornstarch. Data of IR spectroscopy demonstrated that binding to cornstarch polysaccharides decreased the conformational mobility of odorants. The appearance of binding isotherms depended on the extent of sorption, suggesting the involvement of complex mechanisms of binding. The formation of supramolecular complexes through cooperative hydrophobic interactions between aldehydes and cornstarch polysaccharides was the preferential mechanism of the sorption.
A New Method of Visualization of the Enzymatic Activity of Flavocytochrome b 2 in Electrophoretograms by G. Z. Gaida; S. Ya. Stel'mashchuk; O. V. Smutok; M. V. Gonchar (pp. 221-223).
A new method of visualization of the activity of flavocytochrome b 2 (FCC b 2; L-lactate : ferricytochrome c oxidoreductase, EC 1.1.2.3) in electrophoretograms was developed based on the interaction between ferrocyanide (generated during the enzymatic reaction) and Fe3+, resulting in the formation of intensely colored precipitates of Berlin blue. The main advantages of this method were its high sensitivity (less than 0.005 U FCC b 2 was detected within a suitable time period) and the stability of the dye formed. The method developed can be used for determining FCC b 2 activity in cell-free extracts (e.g., in the selection of FCC b 2 producers) and monitoring chromatographic purification of proteins, as well as in other cases associated with FCC b 2 assessment.