Forgot your password?
New user?
New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
CAS announces the release of SciFinder Scholar for Mac OS X
Press Releases
Press Releases
| Check out our New Publishers' Select for Free Articles |
Applied Biochemistry and Microbiology (v.42, #6)
Sorbents with immobilized glycopeptide antibiotics for separating optical isomers by high-performance liquid chromatography by M. A. Kuznetsov; P. N. Nesterenko; G. G. Vasiyarov; S. M. Staroverov (pp. 536-544).
Chiral sorbents for HPLC separation of optical isomers carrying glycopeptide antibiotics (eremomycin or its eremosaminyl aglycon, ristomycin, or vancomycin) fixed onto the surface of silica gel have been synthesized. The patterns of the retention and separation of profen isomers and their dependence on the nature of the chiral selector and the eluant composition have been studied. The sorbents were shown to be highly enantiospecific in separating the isomers of α-amino-, α-hydroxy-, and α-methylphenylcarboxylic acids (profens)
Developmental change of the composition and content of the chitin-glucan complex in the fungus Aspergillus niger by E. P. Feofilova; D. V. Nemtsev; V. M. Tereshina; A. S. Memorskaya (pp. 545-549).
The change of the content and composition of the chitin-glucan complex (CGC) of the ascomycete Aspergillus niger during its development has been studied. In submerged mycelium, the complex is dominated by glucan, whereas chitin is predominant in sporophores and spores. The highest CGC content has been noted in sporophores in the terminal phase and in submerged mycelium in the idiophase; i.e., before the formation of dormant cells. On the grounds of the correlation of the content and composition of lipids, protecting carbohydrates, and CGC, it is suggested that cell wall structural polysaccharides are involved in biochemical adaptation to adverse factors.
Development of a novel enzyme-redox-mediator system based on a fungal laccase and ruthenium complexes by T. V. Fedorova; A. S. Vilesov; S. A. Kurzeev; E. V. Stepanova; E. O. Landesman; O. V. Koroleva (pp. 550-557).
The laccase produced by the fungus Coriolus hirsutus has been coordinatively modified with ruthenium complexes [Ru(phpy)(phen)(MeCN)2]PF6 and Ru(bpy)2CO3 under aerobic and anaerobic conditions. The amount of the complexes per enzyme molecule does not depend on the oxygen concentration, equaling 5 for [Ru(phpy)(phen)(MeCN)2]PF6 and 3 for Ru(bpy)2CO3. The pH dependence of the enzymatic activity, thermostability, and catalytical and electrocatalytical properties of the modified laccase are reported. It has been shown that, during the modification, at least one molecule of the ruthenium compound was coordinated near the T1 active center of the laccase, being directly involved in the catalysis and enhancing its efficiency.
The dynamics of oxidase activity during cultivation of basidiomycetes from the genus Trametes Fr. by E. S. Gorshina; T. V. Rusinova; V. V. Biryukov; O. V. Morozova; S. V. Shleev; A. I. Yaropolov (pp. 558-563).
Twenty strains of the wood-degrading fungi from the genus Trametes Fr., capable of synthesizing laccases, were screened according to the changes in the oxidase activity in a submerged culture. The range of maximal efficiency of various species with respect to extracellular oxidase activity was determined. The absence of correlation between the oxidase activity in a submerged culture and the size of colored zone on agar media (Bavendamm reaction) was demonstrated. The most efficient strains, T. hirsita 56 and T. ochracea 92-78, were used to produce laccases, homogeneous according to SDS electrophoresis data. A number of biochemical parameters characteristic of these enzymes were determined.
Laccase of the lignolytic fungus Trametes hirsuta: Purification and characterization of the enzyme, and cloning and primary structure of the gene by D. N. Rebrikov; E. V. Stepanova; O. V. Koroleva; Zh. I. Budarina; M. V. Zakharova; T. V. Yurkova; A. S. Solonin; O. V. Belova; Z. A. Pozhidaeva; A. A. Leont’evsky (pp. 564-572).
The main physicochemical characteristics of the major isoform of the laccase secreted by the fungus Trametes hirsuta 072 were studied. The enzyme belongs to the group of high redox potential laccases (E T1 0 790 ± 5), and it oxidizes with high efficiency various substrates of phenolic nature. The gene of this isoform was cloned, and its nucleotide sequence was determined. The length of the complete gene is 2134 bp. It comprises 11 exons and 10 introns. Analysis of the amino acid sequence of T. hirsuta 072 laccase demonstrated a high homology to the other laccases secreted by fungi of the genus Trametes.
Properties of hemicellulases of the enzyme complex from Trichoderma longibrachiatum by A. V. Markov; A. V. Gusakov; E. I. Dzedzyulya; B. B. Ustinov; A. A. Antonov; O. N. Okunev; A. O. Bekkarevich; A. P. Sinitsyn (pp. 573-583).
Six xylan-hydrolyzing enzymes have been isolated from the preparations Celloviridin G20x and Xybeten-Xyl, obtained earlier based on the strain 1 Trichoderma longibrachiatum (Trichoderma reesei) TW-1. The enzymes isolated were represented by three xylanases (XYLs), XYL I (20 kDa, pI 5.5), XYL II (21 kDa, pI 9.5), XYL III (30 kDa, pI 9.1); endoglucanase I (EG I), an enzyme exhibiting xylanase activity (57 kDa, pI 4.6); and two exodepolymerases, β-xylosidase (β-XYL; 80 kDa, pI 4.5) and α-L-arabinofuranosidase I (α-L-AF I; 55 kDa, pI 7.4). The substrate specificity of the enzymes isolated was determined. XYL II exhibited maximum specific xylanase activity (190 U/mg). The content of the enzymes in the preparation was assessed. Maximum contributions to the total xylanase activities of preparations Celloviridin G20x and Xybeten-Xyl were made by EG I and XYL II, respectively. Effects of temperature and pH on the enzyme activities, their stabilities under various conditions, and the kinetics of exhaustive hydrolysis of glucuronoxylan and arabinoxylan were studied. Combinations of endodepolymerases (XYL I, XYL II, XYL III, or EG I) and exodepolymerases (α-L-AF I or β-XYL) produced synergistic effects on arabinoxylan cleavage. The reverse was the case when endodepolymerases, such as XYL I or EG I, were combined with α-L-AF I.
Synthesis of xylanolytic enzymes and other carbohydrases by the fungus Penicillium canescens: Transformants with an altered copy number of the gene xlnR and an encoding transcriptional activator by V. A. Serebryanyi; O. A. Sinitsyna; E. A. Fedorova; O. N. Okunev; O. A. Bekkarevich; L. M. Sokolova; E. A. Vavilova; Yu. P. Vitetsky; A. P. Sinitsyn (pp. 584-591).
A fragment of Penicillium canescens genomic DNA carrying the xlnR gene coding for a translational activator of xylanolytic genes was isolated. It was demonstrated that a loss of this function in genetically modified transformants resulted in a drastic decrease in the production of P. canescens major xylanases and had a negative effect on the syntheses of several other extracellular xylanases. An increase in the dose of the xlnR gene elevated the xylanolytic activity as well as the activities of a number of other auxiliary enzymes involved in xylan degradation. The activities of two P. canescens major secreted enzymes—β-galactosidase and α-L-arabinofuranosidase—appeared weakly dependent on the translational activator xlnR.
New cellulases efficiently hydrolyzing lignocellulose pulp by A. A. Skomarovsky; A. V. Markov; A. V. Gusakov; E. G. Kondrat’eva; O. N. Okunev; A. O. Bekkarevich; V. Yu. Matys; A. P. Sinitsyn (pp. 592-597).
Commercial and pilot enzyme preparations from fungi of the genera Penicillium and Trichoderma have been compared with regard to their action on conifer wood pretreated with acidified aqueous ethanol (organosolve). In most experiments, enzymes from the genus Penicillium allowed higher yields of reducing sugars and glucose than those from Trichoderma. High β-glucosidase activity is essential for deep pulp hydrolysis.
Use of a preparation from fungal pectin lyase in the food industry by M. V. Semenova; O. A. Sinitsyna; V. V. Morozova; E. A. Fedorova; A. V. Gusakov; O. N. Okunev; L. M. Sokolova; A. V. Koshelev; T. V. Bubnova; Yu. P. Vinetskii; A. P. Sinitsyn (pp. 598-602).
A new enzyme preparation of fungal pectin lyase (EC 4.2.2.10) was shown to be useful for the production of cranberry juice and clarification of apple juice in the food industry. A comparative study showed that the preparation of pectin lyase is competitive with commercial pectinase products. The molecular weight of homogeneous pectin lyase was 38 kDa. Properties of the homogeneous enzyme were studied. This enzyme was most efficient in removing highly esterified pectin.
Application of neutral-alkaline oectate lyases to cotton fabric boil off by V. V. Morozova; M. V. Semenova; T. N. Salanovich; O. N. Okunev; A. V. Koshelev; T. V. Bubnova; G. E. Krichevskii; A. G. Timatkov; N. V. Barysheva; A. P. Sinitsyn (pp. 603-608).
Commercial and pilot pectate lyase preparations (EC 4.2.2.2) have been compared. They differ in their effect on pectins with different esterification degrees (ED). The activity of the pilot preparation with respect to a substrate with ED = 70% is tenfold lower than with respect to unesterified polygalacturonic acid. For commercial preparations, this activity ratio ranged within 1.5–2. At equal pectate lyase activities, the commercial preparations better remove pectin from crude cotton fabric during its boil off. The laboratory preparation is more efficient for improving the capillarity (wettability) of the fabric owing to the cooperative effect of the pectate lyase, cellulase, and hemicellulase present in the preparation.
Comparison of the efficiency of polygalacturonase and β-glucosidase enzyme preparations in stabilization of cherry plum wine material by E. V. Stepanova; E. O. Landesman; T. V. Fedorova; K. E. Yakovleva; O. V. Koroleva (pp. 609-615).
Pektofoetidin and Pectinex, enzyme preparations with the highest polygalacturonase and β-glucosidase activities, were covalently immobilized on DEAE cellulose and Aminosilochromes 10 and 30. After treatment of cherry plum wine material with the soluble and immobilized enzyme preparations, the content of phenolics increased by 26 and 40%, respectively. The increase was accompanied by a decrease in the protein content (by up to 37%), carbohydrate content (by 17% on the average), and antioxidant activity (5–37%). The most efficient treatment involved Pektofoetidin immobilized on Aminosilochrome 10. It increased the clarity of the wine material and its antioxidant activity by 100 and 10%, respectively.
Hydrolysis of wheat flour with amylase preparations and individual enzymes by I. N. Zorov; M. V. Semenova; N. V. Tsurikova; A. P. Sinitsyn (pp. 616-619).
Rheological properties of wheat flour were studied in the course of its processing (cooking and saccharification). The effects of commercial α-amylase preparations were compared during flour preparation. Test preparations were equally potent in decreasing the viscosity of an all-grain batch. Homogenous glucoamylases isolated from Aspergillus differed in the presence or absence of the starch-binding domain. The starch-binding domain provided for the high activity of glucoamylase on insoluble starch, but gave no advantages in saccharification of pretreated wheat flour.
Effectiveness of enzyme preparations of fodder in the degradation of nonstarch polysaccharides from grain substrates by I. N. Zorov; A. P. Sinitsyn; E. G. Kondrat’eva (pp. 620-624).
The effects of commercial and laboratory preparations were compared in the course of treatment of components of compound fodder. The most potent preparations were selected for the treatment of soybean flower, sunflower meal, and wheat and barley flour. Preparation 181–1008, which had a high proteinase activity, provided the highest yield of protein from soybean flour and sunflower meal. Preparations aGA, AG20X, and VR, characterized by high activities of pectinase and α-galactosidase, as well as laboratory preparation B2000Mix with a high activity of α-galactosidase, provided the highest yield of sugars from soybean flour. Preparations with high α-galactosidase activity were the most potent in hydrolyzing soluble carbohydrates from soybean flour. The highest yield of reducing sugars was observed after treatment of wheat and barley flour with preparations B2000Mix and aGA. Xylanase activity of these preparations was lower than that of preparations 3.130.2 and TG20X. Preparations 3.130.2 and TG20X were the most potent in hydrolyzing wheat middlings.
New poly(3-hydroxybutyrate)-based systems for controlled release of dipyridamole and indomethacin by A. P. Bonartsev; G. A. Bonartseva; T. K. Makhina; V. L. Myshkina; E. S. Luchinina; V. A. Livshits; A. P. Boskhomdzhiev; V. S. Markin; A. L. Iordanskii (pp. 625-630).
New poly(3-hydroxybutyrate)-based systems for controlled release of anti-inflammatory and anti-thrombogenic drugs have been studied. The release occurs via two mechanisms (diffusion and degradation) operating simultaneously. Dipyridamole and indomethacin diffusion processes determine the rate of the release at the early stages of the contact of the system with the environment (the first 6–8 h). The coefficient of the release diffusion of a drug depends on its nature, the thickness of the poly(3-hydroxybutyrate) films containing the drug, the concentrations of dipyridamole and indomethacin, and the molecular weight of the poly(3-hydroxybutyrate). The results obtained are critical for developing systems of release of diverse drugs, thus, enabling the attainment of the requisite physiological effects on tissues and organs of humans.
Preparation of biodegradable porous films for use as wound coverings by N. R. Kil’deeva; G. A. Vikhoreva; L. S. Gal’braikh; A. V. Mironov; G. A. Bonartseva; P. A. Perminov; A. N. Romashova (pp. 631-635).
We studied the preparation of polymeric films formed from solutions of poly-3-hydroxybutyrate and poly-ε-caprolactone in chloroform and methylene chloride. A morphological study of film chips (electron microscopy) showed that solvent evaporation results in the formation of a heterogeneous structure with interpenetrating pores (1–20 μm). We proposed a new method for introducing the proteolytic enzyme and the aminopolysaccharide chitosan into the composition of polyester films. Composite films possessed necrolytic activity and were characterized by increased hydrophilicity. Properties of enzyme-containing films from a mixture of polymers (proteolytic activity, porous structure, and increased hydrophilicity) account for their use in the preparation of biodegradable wound coverings.
Determination of the parameters for producing a biobinder from wood: A mathematical modeling of the transformation of lignocellulose substrate by the fungus Panus tigrinus by V. I. Kondrashchenko; N. S. Manukovsky; V. S. Kovalev (pp. 636-643).
A biochemical scheme for the transformation of wood lignocellulose during enzymatic hydrolysis of polysaccharides and lignin destruction in reactions involving free radicals was developed, and a corresponding mathematical model was constructed. Processing (fermentation) of wood particles by the fungus Panus tigrinus in a submerged culture for producing a biobinder of wood composites—woodchip boards and fiberboards—is considered. The mathematical model was used to study the technological parameters that influence the production of enzymes and fungal biomass and the level of free radical accumulation in the substrate, i.e., the factors determining the production of the biobinder. The optimal values of these parameters were determined, namely: the specific surface of wood particles, amounting to 2000 cm2/g; processing time of 56 h; and an initial concentration of 3.0 g/l of fungal biomass in the submerged culture.