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Applied Biochemistry and Microbiology (v.38, #6)
Polyphenolic Antioxidants Efficiently Protect Urease from Inactivation by Ultrasonic Cavitation by D. I. Metelitza; E. I. Tarun; Yu. P. Losev (pp. 509-516).
Inactivation of urease (25 nM) in aqueous solutions (pH 5.0–6.0) treated with low-frequency ultrasound (LFUS; 27 kHz, 60 W/cm2, 36–56°C) or high-frequency ultrasound (HFUS; 2.64 MHz, 1 W/cm2, 36 or 56°C) has been characterized quantitatively, using first-order rate constants: k in, total inactivation; k in *, thermal inactivation; and k in(us), ultrasonic inactivation. Within the range from 1 nM to 10 μM, propyl gallate (PG) decreases by approximately threefold the rate of LFUS-induced inactivation of urease (56°C), whereas resorcinol poly-2-disulfide stops this process at 1 nM or higher concentrations. PG completely inhibits HFUS-induced inactivation of urease at 1 nM (36°C) or 10 nM (56°C). At 0.2–1.0 μM, human serum albumin (HSA) increases the resistance of urease treated with HFUS to temperature- and cavitation-induced inactivation. Complexes of gallic acid polydisulfide (GAPDS) with HSA (GAPDS–HSA), formed by conjugation of 1.0 nM GAPDS with 0.33 nM HSA, prevent HFUS-induced urease inactivation (56°C).
The Kinetics of Hydrolysis of Animal Fat by Pancreatic Lipase by A. B. German; A. D. Neklyudov; A. N. Ivankin; A. V. Berdutina (pp. 517-520).
Hydrolysis of lipids from beef fat by pancreatic lipase was studied. The maximum release of free fatty acids was shown to occur at 40°C for the first 3 h of the experiment. After this, transetherification was predominant. The main kinetic parameters were the following: maximum hydrolysis rate, V = 1.25 ± 0.1 mg fat/ml min; Michaelis constant, K M H = 100 ± 12 mg fat/ml; constant of substrate inhibition, K S = 10.0 ± 0.8 mg fat/ml; equilibrium constant, K P = 277 ± 170 mg fat/ml; and activation energy of beef fat hydrolysis by pancreatic lipase, E a = 19.1 ± 1.1 kJ/mole. The kinetic method used could be applied to development of the method for biotransformation of poorly assimilated fats into more valuable products.
Deacetylation of Chitin under Homogeneous Conditions by S. V. Nemtsev; A. I. Gamzazade; S. V. Rogozhin; V. M. Bykova; V. P. Bykov (pp. 521-526).
Chitin isolated enzymatically from Antarctic krill shells was dissolved in aqueous NaOH by freezing and thawing to create homogeneous conditions. Deacetylation was performed at room temperature or under heating. The degree of deacetylation, molecular weight, and dynamic viscosity of solutions were estimated in chitosan samples. Deacetylation of chitin under homogeneous conditions was optimized. Chitosans with molecular weights of 180–220 and 250–300 kDa were obtained from the chitins of Antarctic krill and northern shrimp, respectively.
Characteristics of Cyclodextrin Production Using Cyclodextrin Glucanotransferases from Various Groups of Microorganisms by V. A. Abelyan; A. M. Balayan; L. S. Manukyan; K. B. Afyan; V. S. Meliksetyan; N. A. Andreasyan; A. A. Markosyan (pp. 527-535).
Cyclodextrin glucanotransferases (CGTases; EC 2.4.1.19) from newly isolated mesophilic, thermophilic, alkalophilic, and halophilic bacilli, as well as from thermoactinomycetes, were purified to homogeneity, and some of their physicochemical and biochemical characteristics (cyclizing, disproportionating, and hydrolytic activities) were studied. Cyclodextrin (CD) production in the presence and absence of compounds favoring formation of complexes had certain specific features. We were able to demonstrate that CGTases of mesophilic and thermophilic strains form mixtures of α-, β-, and γ-CDs, whereas the enzymes from halophilic and alkalophilic microorganisms preferentially catalyze the formation of β-CD.
Initial Stages of Trisporic Acid Synthesis in Blakeslea trispora by N. N. Gessler; A. V. Sokolov; T. A. Belozerskaya (pp. 536-543).
Biotransformation of β-carotene with enzyme preparations isolated from the mycelium of Blakeslea trispora resulted in the formation of its hydroxylated metabolite and apocarotenals, products of oxidative degradation of this compound. Based on its spectral, chromatographic, and chemical properties, the β-carotene derivative was identified as 4-hydroxy-β-carotene (isocryptoxanthine). One of the products of oxidative degradation of β-carotene, β-apo-13-carotenone, was modified in the presence of enzyme preparations from Blakeslea trispora to form trisporic acid precursors. β-Apo-13-carotenone transformation proceeded more rapidly than β-carotene oxidation at the carbon atom at position 4. The data suggest that, under oxidative stress, oxidative degradation of β-carotene into β-apo-13-carotenone leads to the formation of considerable amounts of trisporic acids.
Biosynthesis of Inulinases by Bacillus Bacteria by N. A. Zherebtsov; S. A. Shelamova; I. N. Abramova (pp. 544-548).
Biosynthesis of extracellular inulinase by bacteria Bacillus polymyxa 29,B. polymyxa 722, and B. subtilis 68 was studied. The optimal parameters for the producer growth were as follows: pH 7.0, 33–35°C, growth duration 72 h. The presence of reduced mineral nitrogen or organic nitrogen was necessary for the enzyme biosynthesis. The inulinase biosynthesis was sharply activated in the presence of carbohydrates. B. polymyxa 722 and B. polymyxa 29 displayed the maximum activities on a starch-containing culture medium; the maximum activity of B. subtilis 68 was in the presence of sucrose. Inulin did not induce inulinase biosynthesis by the strains studied. The time course of bacteria growth and enzyme biosynthesis was studied.
Production, Characterization, and Properties of β-Glucosidase and β-Xylosidase from a Strain of Aureobasidium sp. by T. Iembo; R. da Silva; F. C. Pagnocca; E. Gomes (pp. 549-552).
β-Glucosidase and β-xylosidase production by a yeastlike Aureobasidium sp. was carried out during solid-state and submerged fermentation using different carbon sources and crude enzymes were characterized. β-Glucosidase and β-xylosidase exhibited optimum activities at pH 2.0–2.5 and 3.0, respectively. These enzymes had the maximum activities at 65°C and were stable in a wide pH range and at high temperatures.
Synthesis of Biologically Active Lipids by the Fungus Mucor lusitanicus 306D Grown on Media with Various Composition by N. S. Funtikova; I. S. Mysyakina; I. V. Konova (pp. 553-557).
Growth and lipogenesis of the fungusMucor lusitanicus306D, producing γ-linoleic acid, was studied under various conditions of nitrogen and carbon nutrition. Media containing food-industry wastes, such as maize extract, molasses, and protein hydrolysate, were used. The content of γ-linoleic acid was higher when carbohydrates (glucose and molasses) were used as carbon sources and urea was used as a nitrogen source. At a high glucose concentration (100 g/l), fed batch cultivation ensured high contents of γ-linoleic acid in lipids (1 g/l). After extraction of lipids, the fungus biomass was 42% protein, containing all essential amino acids. A defatted biomass was shown to be effectively assimilated by minks.
Reduction of Nitrates by Azotobacter indicum and Azotobacter chroococcum Cultures by E. K. Furina; D. A. Nikolaeva; G. A. Bonartseva; V. L. Myshkina; N. P. L'vov (pp. 558-561).
The capacity for denitrification was studied in Azotobacter bacteria, which are free-living nitrogen-fixing obligatory aerobes. Data on nitrate reduction to nitrites and nitric oxide by A. indicum under anaerobic conditions were obtained for the first time for genus Azotobacter.
Growth Phase Dependent Substrate Utilization by PseudomonasStrain PH by G. K. Narde; H. J. Purohit (pp. 562-566).
Pseudomonas strain PH1 can utilize nitro-, chloro-, and aminophenols and was used in this study. The enzymes of two pathways, utilizing phenol and meta-aminophenol (MAP), were analyzed under different growth conditions. The enzymes responsible for phenol to catechol conversion followed by the ring cleavage enzyme for catechol, and also the enzymes responsible for MAP oxidation and hydroxylation of resorcinol, were studied. Enzyme and respirometric assays were carried out with cells harvested from log phase and stationary phase from medium with different carbon sources and nitrogen levels. It was observed that the first step for utilization of both the substrates requires the same physiological state of the cells, whereas, the subsequent step require different physiological states.
Isolation of the Ergot Strain Claviceps purpurea(Fr.) Tul. VKM-F-3662D Producing the Lactamic Alkaloid Ergocornam by E. L. Komarova; S. S. Shain; V. I. Sheichenko (pp. 567-571).
A new ergot strain, VKM-F-3662D, producing lactamic alkaloid ergocornam with concomitant alkaloids valinamide and ergometrine, was isolated during selective work with sclerotium MS-462, which was obtained from ergocryptine ergot strain VKM-F-2642D. The structure of these alkaloids was determined by 1H and 13C NMR.
Obtaining of a High-Density Culture ofNocardioides sp. by V. M. Ananjin; V. V. Fokina; G. V. Sukhodolskaya; M. V. Donova (pp. 572-575).
Selection of carbon sources demonstrated ethanol to be the best substrate for a high-density Nocardioides sp. culture. A strategy for control over high-density fed-batch culture production was developed, which permitted maximizing the yield of biomass (21 g/l). The control, based on the ExpoDense algorithm, should be predetermined at the first phase and adaptive in the second phase of the two-phase process of high-density culture production.
Development of the Biological Preparation Enatin with Broad-Range Antimicrobial Action by T. V. Romanovskaya; E. I. Kolomiets; N. A. Zdor; A. G. Lobanok (pp. 576-582).
Physiological and biochemical traits of the epiphytic spore-forming bacteria Bacillus pumilusBIM B-263 were examined. The nutrient medium and conditions for submerged cultivation of the strain were selected. The growth dynamics and antagonistic activity during cultivation in an ANKUM-2M laboratory fermenter were studied. The results provide grounds for development of the biological preparation Enatin, with broad-range antimicrobial effect. The plant-protective and growth-stimulating effect of Enatin was examined in laboratory and field experiments. The preparation holds promise as means for biological control of crop pathogens.
Binding of Lactones by Polysaccharides of Corn and Potato Starches by T. A. Misharina; M. B. Terenina; N. I. Krikunova (pp. 583-587).
Sorption of γ- and δ-lactones from aqueous solutions by cryotropic gels of corn and potato starches was studied using capillary gas–liquid chromatography and Fourier transform infrared spectroscopy. The sorption patterns were similar for both types of starch. However, the sorption of lactones by potato starch was 5–10% lower than their sorption by corn starch. The amount of substances bound by cryotextures of the starches depended linearly on their initial concentrations in the gel. An increase in the length of the alkyl substituent improved sorption of lactones. It was shown that six-membered rings play a greater role in total lactone sorption than five-membered rings. The apparent constants and numbers of binding sites were estimated for compounds that reached the stage of saturation. The interaction between lactones and polysaccharides was accompanied by a decrease in their conformational mobility and changes in the rheological characteristics of thermotropic and cryotropic starch gels.
The Immunoregulatory Effects of Endoglucanase Preparations on Plant Resistance to Fungal Infections by M. N. Talieva; N. A. Rodionova; L. V. Runkova; E. P. Pavlenko; E. S. Vasilenko; L. S. Olekhnovich; N. A. Zagustina; A. M. Bezborodov (pp. 588-592).
The effects of enzymatic preparations—pectomacerin, hemicellulase, andTrichoderma viride 13/10 cellulase—on plant immunological status were studied using two pathosystems, carrot root–white rot agent (Sclerotinia libertiana) and carrot root–black rot agent (Rhizopus nigricans) as examples. It was demonstrated that these preparations reduced the plant damage by infections, namely, decreased the permeability of cell membranes in the infected tissue and stimulated its defense responses, which were expressed as a stable elevation in the content of phenolic compounds and formation of tissue protective barriers.
Effect of Preparations Exhibiting Cytokinin-like Activity on the Specific Density of Leaf in Grasses by I. I. Chernyad'ev (pp. 593-601).
The effects of synthetic preparations exhibiting cytokinin-like activity (6-benzylaminopurine, Thidiazuron, and kartolin-2) on the specific leaf area (SLA) were studied in plants of the family Gramineae (wheat, Triticum aestivum L.; meadow fescue, Festuca pratensis Huds.; and reed fescue, F. arindinacea Schreb.). At the early stages of ontogeny (until the leaf area reached 50–60% of the maximum value), treatment of plants of the three species with cytokinin-like preparations caused an increase in SLA. The SLA value in these plants was correlated with the rate of photosynthetic assimilation of carbon dioxide and activities of carbon metabolism enzymes: ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39), NAD-malate dehydrogenase (EC 1.1.1.37), and NADP-glyceraldehydephosphate dehydrogenase complex, which includes phosphoglycerate kinase (EC 2.7.2.3) and glyceraldehydephosphate dehydrogenase (EC 1.2.1.13). However, there was no correlation of SLA with the activity of phospho(enol)pyruvate carboxylase (EC 4.1.1.31), an anaplerotic carboxylation enzyme of grasses. SLA is suggested to reflect the state and activity of the photosynthetic apparatus and can be recommended as a characteristic of photosynthesis variability (e.g., caused by cytokinin-like preparations).
Morphogenetic Changes in Ambiol-Treated Regenerants of Parent and Transgenic Potato Plants by T. A. Platonova; A. S. Evsyunina; N. S. Lyapkova; N. P. Korableva (pp. 602-606).
The effects of ambiol, a new growth regulator, on the formation of leaves and roots in parent and defensin-gene-transformed regenerants of potato Solanum tuberosum L. (cultivarDesire) were studied. Various concentrations of ambiol induced differences in morphogenetic parameters between parent and transgenic plants. In some cases, ambiol caused the formation of shoots without leaves or with rudimentary leaves. The data suggest that features of root and leaf formation in parent and transgenic regenerants induced by ambiol are due to changes in hormone balance in transgenic plants caused by expression of the defensin gene and the effect of ambiol on the plant hormonal balance.
Photometric Assay for Methanol in the Presence of Ethanol by Yu. V. Rodionov; M. V. Sukhacheva; O. I. Keppen (pp. 607-609).
A new enzymatic photometric assay for determination of methanol and ethanol in solutions containing both alcohols is described. The assay allows detection of methanol in the concentration range of tens of ppm in the presence of tens of percent of ethanol. The lower determination threshold for methanol is at least 0.002% in the presence of 45% ethanol, with a coefficient of variation of 0.02–0.05. General-purpose spectrophotometers and photoelectric colorimeters can be used in the measurements.