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Applied Biochemistry and Microbiology (v.39, #3)
Nutritive Fibers of Animal Origin: Collagen and Its Fractions as Essential Components of New and Useful Food Products by A. D. Neklyudov (pp. 229-238).
Data on the production of collagen and its fractions (which in many cases surpass the parent protein in functional properties) reported in the literature throughout the past two decades are reviewed. The material presented elucidates the role played by collagen and its fractions in the development of new, ecologically pure foodstuffs containing nutritive fibers. As follows from the analysis of these data, collagen fractions with molecular weights in excess of 120 kDa offer the greatest promise for producing useful foodstuffs.
Effect of the Degree of Acetylation of Chitosan on Its Enzymatic Hydrolysis with the Preparation Celloviridin G20kh by A. V. Il'ina; V. P. Varlamov (pp. 239-243).
The degree of acetylation was shown to exert only insignificant effects on the enzymatic hydrolysis of chitosan, while affecting the composition of the resulting hydrolysates and their water solubility. Chitosan with various degrees of acetylation was produced by reacetylation of the initial chitosan (the solvents, methanol and 2% acetic acid, were present in a ratio of 54 : 51 v/v; the amount of acetic anhydride was in the range 0.1–2.0 mmol per gram chitosan). Hydrolysis by the enzymatic preparation Celloviridin G20kh was performed at an enzyme-to-substrate ratio of 1 : 400 in sodium–acetate buffer, pH 5.2 (55°C) for 1 h.
Optimization of Synthesis of Ethyl Isovalerate Using Rhizomucor miehei Lipase by G. V. Chowdary; S. G. Prapulla (pp. 243-248).
Immobilized lipase from Rhizomucor miehei (Lipozyme IM-20) was used to catalyze the esterification reaction between isovaleric acid and ethanol to synthesize ethyl isovalerate in n-hexane. Response surface methodology based on a four-variable, five-level, central composite rotatable design was employed to optimize four important reaction variables—enzyme/substrate (E/S) ratio, substrate concentration, incubation time, and temperature—affecting the synthesis of ethyl isovalerate. The optimum conditions predicted for achieving maximum ester yield (500 mM) are as follows: E/S ratio, 48.41 g/mol; substrate concentration, 1 M; reaction time, 60 h; and temperature, 60°C. The predicted value matched well with the experimentally obtained value of 487 mM.
Mechanism of Overproduction of Secreted Enzymes in the Mycelial Fungus Penicillium canescens by E. A. Vavilova; S. V. Antonova; E. D. Barsukov; Yu. P. Vinetskii (pp. 249-256).
The fungus Penicillium canescens strain F178 (VKPM) and its niaD – mutant exhibited an increased capability of synthesizing extracellular enzymes β-galactosidase (50–60 U/ml) and xylanase (100 U/ml). The synthesis was induced by arabinose and its catabolite, arabitol. A deficiency in arabitol dehydrogenase, leading to arabitol accumulation in the cell, was detected in the chain of reactions of arabinose catabolism. The increased synthesis of β-galactosidase and xylanase in P. canescens is accounted for by (1) cellular accumulation of the inducer (arabitol) at low concentrations of arabinose in the medium and (2) prevalence of induction over repression.
Isolation and Characterization of Humin-Like Substances Produced by Wood-Degrading White Rot Fungi by I. S. Yavmetdinov; E. V. Stepanova; V. P. Gavrilova; B. V. Lokshin; I. V. Perminova; O. V. Koroleva (pp. 257-264).
Three samples of high-molecular-weight humin-like substances were obtained by solid-phase cultivation of Coriolus hirsutus and/or Cerrena maxima on oat straw. The yield of humin-like substances amounted to 1.38–2.26% of the weight of the plant substrate consumed. These substances, produced both by individual and mixed cultures of the basidiomycetes, were shown to be similar in their structure and physicochemical properties. According to the data of IR and 13C-NMR spectroscopy, the substances contained aromatic fragments and were close to soil humic acids. Studies of the dynamics of laccase production suggested that the humin-like substances were produced via direct degradation of lignin macromolecules with direct involvement of extracellular laccase.
Specific Features of Fermentation of D-Xylose and D-Glucose by Xylose-Assimilating Yeasts by E. N. Yablochkova; O. I. Bolotnikova; N. P. Mikhailova; N. N. Nemova; A. I. Ginak (pp. 265-269).
The ability to assimilate D-glucose and D-xylose was studied in 21 yeast species of the following genera: Candida, Kluyveromyces, Pachysolen, Pichia, and Torulopsis. All the cultures fermented D-glucose with the formation of ethanol. During the assimilation of D-xylose, ethanol was produced by P. stipitis and C. shehatae, whereas xylitol was produced by C. didensiae, C. intermediae, C. parapsilosis, C. silvanorum, C. tropicalis, K. fragilis, K. marxianus, P. guillermondii, and T. molishiama. The yeast P. tannophilus produced comparable amounts of both alcohols. The possible use of xylose-assimilating yeasts for the production of xy-litol and ethanol is discussed.
Effect of Antibacterial Factors and Biostimulators of Cell Metabolism on Bacterial Luminescence by R. A. Pshenichnov; I. L. Maslennikova; N. M. Nikitina (pp. 270-274).
Bioluminescence was used as an index of effects of a series of factors (differing in origin and structure) on cell metabolism. Luminescence of intact cells of Escherichia coli lum+ (a genetically modified strain) was measured on exposure to antibiotics, probiotics, phages, and biostimulators. The sensitivity of E. coli lum+ to antibiotics correlated with antibiotic-induced luminescence quenching. Bioluminescence-based assessment of the antagonistic activity of the main probiotics (bificol, bifidobacterin, acylact, colibacterin, and a composite probiotic preparation), each taken at a concentration of 1 dose/ml, demonstrated that bacterial luminescence was inhibited by 75–99.9% (exposure time, 30 min). Bioluminescence changes reflected cell damage associated with phage infection. It was shown that bioluminescence stimulation could be used as an index of the effect of immunomodulators (olexin and vermin) on cell metabolism in bacterial cultures.
Specific Toxic Effects of 2,4,6-Trinitrotoluene on Bacillus subtilisSK1 by B. M. Kurinenko; G. Yu. Yakovleva; N. A. Denivarova; Yu. V. Abreimova (pp. 275-278).
Using Bacillus subtilis SK1 as an example, it was demonstrated for the first time that 2,4,6-trinitrotoluene (TNT) transformation pathways change with TNT concentration. The growth of cultured B. subtilis SK1, delayed at 20 mg/l TNT (minimum toxic concentration), was resumed following TNT transformation. Aromatic amines were predominant metabolites detected in the culture medium at early stages of TNT transformation. The culture growth was completely inhibited by 200 mg/l TNT. As this took place, nitrites accumulated in the culture medium.
Use of Bacteria of the Genus Azotobacter for Bioremediation of Oil-Contaminated Soils by N. B. Gradova; I. B. Gornova; R. Eddaudi; R. N. Salina (pp. 279-281).
The rate of self-purification of oil-contaminated soil increases after introduction of bacteria of the genus Azotobacter. The bacteria can assimilate oil hydrocarbons as the sole source of carbon and energy, both in the presence of fixed nitrogen and during nitrogen fixation. The species Azotobacter chroococcum activates growth of hydrocarbon-oxidizing bacteria present in Devoroil.
Growth of Bacteria Degrading Naphthalene and Salicylate at Low Temperatures by V. G. Grishchenkov; D. A. Shishmakov; I. A. Kosheleva; A. M. Boronin (pp. 282-288).
A total of 58 bacterial strains degrading naphthalene and salicylate were isolated from soil samples polluted with oil products, collected in different regions of Russia during winter and summer. The isolates were assessed for their ability to grow at low temperatures (4, 8, and 15°C); bacteria growing at 4°C in the presence of naphthalene or salicylate accounted for 65 and 53%, respectively, of the strains isolated. The strains differed in the temperature dependence of their growth rates. It was demonstrated that the type of expression of the Nah+ phenotype at low temperatures depended on the combination of host bacterium and plasmid.
Quantitative Assessment of the Biocidal Activity of Chemicals Using Soil Microbial Associations by E. A. Gil'vanova; N. G. Usanov (pp. 289-293).
Quantitative assessment, using three Pseudomonas sp. strains, of the activity of the microbial biocide Soncid 8101 demonstrated that the values of effective sublethal concentrations (L50) differed by 500% (because of individual variations in the sensitivity of the test strains). The spread of parameters of biocidal activity could be narrowed by using a mixture of microorganisms with high, medium, and weak resistance. A method for quantitative assessment of the activity of microbial biocides was proposed based on the use of natural associations of soil bacteria.
Optimization of Conditions for Storage and Cultivation of the Fungus Claviceps sp., a Producer of the Ergot Alkaloid Agroclavine by L. V. Boichenko; N. F. Zelenkova; M. U. Arinbasarov; T. A. Reshetilova (pp. 294-299).
Conditions of agroclavine biosynthesis by the mutant Claviceps sp. strain c106 were studied. The content of agroclavine was maximum (1.5–2 g/l) on days 15–16 of cultivation in the complex medium T25, containing sucrose, citric acid, and yeast extract. Agroclavine was the major component of the alkaloid fraction (90–95%). Storage of the culture at –70°C in T25 supplemented by 7% glycerol provided a stable level of alkaloid formation.
Phytohormone Interactions in the Control of Proton Translocation Activity of Plant Cell Plasmalemmata by E. P. Ladyzhenskaya; N. P. Korableva (pp. 300-303).
The effects of phytohormones (abscisic acid, gibberellic acid, and jasmonic acid) and ambiol (a synthetic growth regulator) on processes of H+ transport across the plasmalemma were studied in membrane vesicles isolated from the parenchyma of potato (Solanum tuberosum L.) tubers. Phytohormones and ambiol were tested either individually or in combinations. Each of the substances tested changed the initial rate of H+ uptake by the vesicles. Two signaling substances added to the incubation medium simultaneously modified the activity of each other. It is suggested that the interaction of a signaling substance with components of the plasmalemma alters the responses of the membrane to other signaling molecules.
Free and Bound Amino Acids during Germination of Maize Seed with Preincorporated Foreign Prolamines by O. A. Novozhilova; A. S. Timoshchenko; L. P. Aref'eva; V. F. Semikhov (pp. 304-310).
Wheat prolamines were preincorporated into the endosperm of maize seed, and concentrations of free and bound amino acids were measured in the endosperm and seedlings during seed germination. Incorporation of foreign prolamines lowered the rate of decrease of free proline concentration in both the endosperm (sprouting and shoots) and the embryo (sprouting). The seedlings at the stage of shoots were characterized by higher concentrations of aspartic acid, glutamic acid, and tyrosine. At the stage of transition to autotrophic nutrition, the pool of amino acids that are physiologically important for plant growth was greater in maize seedlings with incorporated wheat prolamines.
Changes in the Composition of the Essential Oil of Marjoram during Storage by T. A. Misharina; A. N. Polshkov; E. L. Ruchkina; I. B. Medvedeva (pp. 311-316).
The composition of volatile components of the essential oil of marjoram plants (Majorana hortensis M.) and its stability during storage were studied by capillary gas chromatography and gas chromatography/mass spectrometry. Storage in the dark for 1 year was associated with insignificant changes in the composition of the essential oil, and its organoleptic characteristics remained largely unaffected. Storage in the light produced considerable changes in the composition of the oil, due to chemical transformations of terpenoids.
Polymeric Systems with Antithrombin Activity for Thermally Activated Targeting by I. L. Valuev; A. V. Pan; M. A. Rozenfel'd; L. I. Valuev; N. A. Platé (pp. 317-320).
Copolymers of N,N-diethylacrylamide and N-acryloylphthalimide with a lower critical solution temperature (LCST) were synthesized by radical copolymerization. Polymeric systems with antithrombin activity and an LCST were prepared via a reaction of amino groups of hirudin with phthalimide groups of the copolymers. On increasing hirudin content, the LCST of the polymeric systems increased. The antithrombin activity of polymeric systems obtained by hirudin immobilization on copolymer carriers was inversely related to the content of the copolymer, amounting to 6% of the activity of native hirudin.
Kinetics of Chemical Reactions for Prediction of Quality of Canned Fish during Storage by M. V. Lukoshkina; G. A. Odoeva (pp. 321-327).
Changes in a wide range of quality characteristics of canned fish were studied during storage at different temperatures. A number of biochemical parameters were found that undergo significant monotonic changes in the course of storage, correlating with organoleptic scores. It was demonstrated that simulation of thermal aging of canned fish on the basis of on the laws of chemical kinetics may be used for predicting quality changes and determining shelf life.