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Applied Biochemistry and Microbiology (v.43, #6)
Aerotolerance of strictly anaerobic microorganisms and factors of defense against oxidative stress: A review by A. L. Brioukhanov; A. I. Netrusov (pp. 567-582).
Effects of aerobic conditions on strictly anaerobic microorganisms belonging to diverse taxa (clostridia, acetogenic bacteria, lactic acid bacteria, bacteroids, sulfate-reducing bacteria, and methanogenic archaea) and differing considerably in their oxygen resistance have been reviewed, with emphasis on the role of aerotolerance in the ecology of anaerobes. Consideration is given to components of nutritive media for anaerobe culturing, which decrease the toxic effects of oxygen and there by contribute significantly to maintenance and storage of industrial cultures of strictly anaerobic microorganisms. Physiological and biochemical factors are described, accounting for the relative resistance of many strict anaerobes to oxygen and products of incomplete reduction thereof. Specific attention is given to regulation of enzymes of antioxidative defense, operating in the cells of strict anaerobes under the conditions of oxidative stress caused by oxygen, superoxide anion, or hydrogen peroxide.
Stabilizing effect of Azospirillum lectins on β-glucosidase activity by S. A. Alen’kina; V. R. Zharkova; V. E. Nikitina (pp. 583-586).
Lectins from the surface of Azospirillum brasilense Sp7 and Azospirillum brasilense Sp7.2.3 (a mutant with impaired lectin activity) were shown to induce a stabilizing effect on the activity of almond β-glucosidase under conditions of thermoinactivation and proteolytic enzyme treatment. Differences were revealed in the influence of lectins with various antigenic properties. Our results indicate that the effects of lectins on the catalytic activity of the enzyme are mainly associated with conformational changes in lectin molecules during mutagenesis, but not with carbohydrate specificity (general property). These data should be taken into account in evaluating the role of lectins in the formation of nitrogen-fixing associations.
Kinetics of the degradation of aliphatic hydrocarbons by the bacteria Rhodococcus ruber and Rhodococcus erythropolis by D. V. Zhukov; V. P. Murygina; S. V. Kalyuzhnyi (pp. 587-592).
Consumption of aliphatic hydrocarbons by the bacteria Rhodococcus ruber Ac-1513-D and Rhodococcus erythropolis Ac-1514-D grown on mixed n-alkanes and diesel fuel was studied. Consumption of diesel fuel hydrocarbons by the strains was less intense in comparison with the n-alkane mixture. The strains showed differences in growth rate and consumption of the substrates, which suggests that they possess different mechanisms of hydrocarbon uptake.
Changes of chlorine isotope composition characterize bacterial dehalogenation of dichloromethane by A. M. Zyakun; Yu. E. Firsova; M. L. Torgonskaya; N. V. Doronina; Yu. A. Trotsenko (pp. 593-597).
Fractionation of dichloromethane (DCM) molecules with different chlorine isotopes by aerobic methylobacteria Methylobacterium dichloromethanicum DM4 and Albibacter methylovorans DM10; cell-free extract of strain DM4; and transconjugant Iethylobacterium extorquens AI1/pME 8220, expressing the dcmA gene for DCM dehalogenase but unable to grow on DCM, was studied. Kinetic indices of DCM isotopomers for chlorine during bacterial dehalogenation and diffusion were compared. A two-step model is proposed, which suggests diffusional DCM transport to bacterial cells.
Comparison of genotypic and biochemical characteristics of Streptococcus thermophilus strains isolated from sour milk products by S. G. Botina; M. A. Trenina; Yu. D. Tsygankov; V. V. Sukhodolets (pp. 598-603).
Overall, 72 strains of lactic acid thermophilic streptococci isolated from sour milk products manufactured in various regions of Russia and European countries were analyzed using classical microbiological and molecular biological methods. Physiological and biochemical properties and genetic diversity of these Streptococcus thermophilus strains were studied, and a comparative analysis of the nucleotide sequences of the 16S rRNA gene was conducted. It has been demonstrated that the homology of proximal parts of the 16S rRNA gene of all the strains studied towards one another and towards the reference strain ATCC19258 amounts to 100%. As for the sugar fermentation, some strains display the characteristics untypical of the S. thermophilus members. The data obtained suggest that it is preferable to use gene 16S rRNA sequencing data for identification of natural isolates of closely related lactic acid bacterial species; moreover, this method is recommended for a precise species identification of industrial bacterial strains used in the food industry.
A comparison of the properties of bacteriocins formed by Lactococcus lactis subsp. lactis strains of diverse origin by L. G. Stoyanova; N. S. Egorov; G. B. Fedorova; G. S. Katrukha; A. I. Netrusov (pp. 604-610).
Bacteriocins formed by four strains of Lactococcus lactis subsp. lactis have been studied and compared: 729 (a natural strain isolated from milk), 1605 (a mutant of strain 729), F-116 (a recombinant obtained by fusing of protoplasts of the two related strain 729 and 1605), and a nisin-forming strain obtained by adaptive selection at Moscow State University. Antimicrobial activity studies revealed differences between the strains in the effects on individual groups of microorganisms; the activities of the strains were also distinct from that of Nisaplin (a commercial preparation of the bacteriocin nisin). Methods for isolation and purification of bacteriocins have been developed, making it possible to obtain individual components of antibiotic complexes as chromatographically pure preparations. Bacteriocins formed by the strains of Lactococcus lactis subsp. lactis have been identified and differences in their biological and physicochemical properties, established. A novel potent broad-spectrum antibiotic substance distinct from nisin has been isolated from the recombinant strain F-116.
Antimicrobial activity of core-sheath surgical sutures modified with poly-3-hydroxybutyrate by M. B. Fedorov; G. A. Vikhoreva; N. R. Kil’deeva; O. N. Mokhova; G. A. Bonartseva; L. S. Gal’braikh (pp. 611-615).
To impart antimicrobial activity to surgical sutures, weaved polyester fibers are coated with poly-3-hydroxybutyrate (PHB), containing the antimicrobial agent furazolidone (FZ). The prolonged FZ effect (7–14 days) is achieved by two-step application of a sheath, constituting 10% of the suture weight and containing 2–6% FZ. The sheath structure and antimicrobial activity of sutures can be modified by the introduction of other biocompatible and biodegradable polymers.
Conversion of polychlorophenols by laccases with 1-hydroxybenzotriazole as a mediator by A. V. Lisov; Z. A. Pozhidaeva; E. V. Stepanova; O. V. Koroleva; A. A. Leontievsky (pp. 616-619).
The action of purified laccase from the basidial fungi Cerrena unicolor and Trametes sp. on 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP) was studied, including reactions involving 1-hydroxybenzotriazole as a mediator. Oxidation of 2,4,6-TCP by laccase without the mediator yielded 2,6-dichlorobenzoquinone as a primary conversion product, whereas PCP was not oxidized. Products of further conversion of 2,4,6-TCP and PCP formed with the presence of the mediator.
A study of steroid hydroxylation activity of Curvularia lunata mycelium by V. V. Yaderets; V. A. Andryushina; Yu. E. Bartoshevich; A. G. Domracheva; M. I. Novak; T. S. Stytsenko; N. E. Voishvillo (pp. 620-624).
It has been demonstrated that the mycelium of Curvularia lunata at the end of the logarithmic growth phase displays a maximal 11β-hydroxylase activity towards cortexolone (4–6 g/l) used for transformation as a microcrystalline suspension in phosphate buffer. The mycelium at a later stage of fungal growth displays an elevated 14α-hydroxylase activity, necessary for generation of 14α-hydroxyandrostenedione. The effects of different forms of substrate added to the reaction mixture, age and concentration of mycelium, and fungal clones tolerant to salts of heavy metals (0.35–0.5%) were studied to remove the side 14α-hydroxylation, accompanying the main cortexolone transformation. Mycelia of the fungal clones tolerant to Co2+ and Cu2+ displayed a weak hydroxylase activity or its complete absence and an elevated content of melanin, the biosynthesis of which is intensified under adverse conditions. The results obtained suggest that the transformation of steroids by the studied C. lunata strain is a detoxication of foreign compounds.
Effect of quinocitrinines from the fungus Penicillium citrinum on the respiration of yeasts and bacteria by A. Yu. Arinbasarova; A. G. Medentsev; A. G. Kozlovskii (pp. 625-628).
We studied the effect of quinocitrinines on the respiratory activity of yeasts (Yarrowia lipolytica) and bacteria (Arthrobacter globiformis). Quinocitrinines were shown to activate respiration of native cells in both types of organisms. Studies of yeast mitochondria showed that quinocitrinine exerts an uncoupling effect on oxidative phosphorylation, which activates the respiration, reduces the respiratory control, and decreases the ADP/O ratio. Experiments with intact mitochondria and native cells of Arthrobacter globiformis revealed that quinocitrinine decreases the membrane potential. The uncoupling effect likely constitutes a mechanism of the antibiotic activity of quinocitrinines.
Antibacterial activity of polyphenolic compounds isolated from plants of Geraniaceae and Rosaceae families by V. S. Nikitina; L. Yu. Kuz’mina; A. I. Melent’ev; G. V. Shendel’ (pp. 629-634).
Polyphenolic compounds present in extracts of plants belonging to the families Geraniaceae (blood-red cranesbill, wood cranesbill, meadow cranesbill, and alfilaria) and Rosaceae (red raspberry, European dewberry, and tormentil) have been tested for their activity against gram-positive and gram-negative bacteria of the genera Azotobacter, Bacillus, and Pseudomonas. The bacteriostatic activity exhibited some species-related features and depended on the polarity of the extracting agent. The bacteriostatic activity of plant-derived phenolic compounds correlated with their antioxidant potential. The plants of the families Geraniaceae and Rosaceae offer promise as a source of raw material for isolation of polyphenolic compounds exhibiting bactericidal activity, including against opportunistic pathogens (B. cereus, E. coli, P. aeruginosa, and S. aureus strains).
The effect of Furolan on the physiological and biochemical characteristics of ripening winter wheat grain by N. I. Nen’ko; V. K. Plotnikov; N. A. Kuzembaeva; V. N. Garazha; E. V. Surkova; A. I. Nasonov; Yu. S. Pospelova; N. G. Malyuga (pp. 635-640).
The effects of the preparation Furolan, (2-furyl-2)-1,3-dioxolane, on the degree of mRNA polyadenylation and the pattern of protein synthesis in the ripening grain of several soft winter wheat (Triticum aestivum L.) cultivars were studied. It was demonstrated that Furolan stabilized mRNA in a cultivar-specific manner, thereby accelerating to various degrees the biochemical processes taking place in the ripening grain. Of the wheat cultivars studied, Krasnodarskaya 99 was the most responsive cultivar with respect to a set of changes in nucleic-protein metabolism; the cultivar Deya was next followed by the cultivar Bat’ko. The cultivar Kroshka did not respond to the treatment with Furolan. The cultivar specificity of this preparation allows its practical application to be optimized.
A protector effect of cytokinin preparations on the photosynthetic apparatus of wheat plants under water deficiency conditions by O. F. Monakhova; I. I. Chernyad’ev (pp. 641-649).
The protective effects of the cytokinin 6-benzylaminopurine and the compounds thidiazuron and kartolin, displaying a cytokinin activity, on the photosynthetic apparatus of young seedlings and leaves of adult plants of two wheat (Triticum aestivum L.) cultivars, Mironovskaya 808 (more drought tolerant) and Lutescens 758 (less tolerant to water stress), were compared on the background of an increasing water deficiency. At the stages of drought and subsequent rehydration, kartolin preparations were the most efficient protectors, enhancing a less pronounced decrease in the intensity of photosynthesis, carboxylating activity of the key enzyme of carbon metabolism—ribulose bisphosphate carboxylase/oxygenase (EC 4.1.1.39)—and the activity of NADP—glyceraldehyde phosphate dehydrogenase—the enzyme complex comprising phosphoglycerate kinase (EC 2.7.2.3.) and glyceraldehyde phosphate dehydrogenase (EC 1.2.1.13). This effect also included an increase in the leaf specific density and plant productivity. The negative influence of water stress on the photosynthetic apparatus was more pronounced in a less tolerant cultivar Lutescens 758 and in the seedlings as compared with the adult plants.
Anticoagulant activity of low-molecular-weight sulfated derivatives of galactomannan from Cyamopsis tetragonoloba (L.) seeds by N. M. Mestechkina; V. D. Shcherbukhin; G. E. Bannikova; V. P. Varlamov; N. N. Drozd; A. S. Tolstenkov; V. A. Makarov; V. E. Tikhonov (pp. 650-654).
Galactomannan from seeds of Cyamopsis tetragonoloba (L.) Taub. (guar) was depolymerized using immobilized enzymatic preparation celloviridin. A set of fragments whose molecular weights varied from 12.6 to 245.6 kDa was obtained. Sulfated derivatives of components of all fractions were synthesized, in which the content of HSO 3 − groups was 48.05 ± 2.31%. All preparations exhibited anticoagulant activity, which was recorded in vitro in two tests—alla and aXa. The antithrombin activity (aIIa) was high (up to 65–87 U/mg) and did not depend on the molecular weight of a sulfated derivative; in the second test (aXa), the effect of molecular weight was observed. Biospecific electrophoresis allowed us to detect the ability of galactomannan sulfates to form complexes with protamine sulfate, a classic antidote to heparin.
Inhibition of lipase activity by low-molecular-weight chitosan by E. S. Ostanina; V. P. Varlamov; G. I. Yakovlev (pp. 655-660).
Inhibition of enzymatic activity of lipase (EC 3.1.1.3) from the fungus Candida rugosa and wheat (Triticum aestivum L.) germ by low-molecular-weight chitosan with an average molecular weight of 5.7 kDa in reactions of p-nitrophenyl palmitate cleavage was studied. Preincubation of lipases with chitosan, prior to addition of the substrate to solution, showed that equilibrium during the lipase-inhibitor complex formation was reached within 30 min. The inhibition constants for C. rugosa lipase and wheat germ lipase were 1.4 and 0.9 mM, respectively. The contribution of electrostatic interactions to the complex formation between chitosan and lipases is insignificant.
Characterization of plant phenolic compounds by cyclic voltammetry by K. E. Yakovleva; S. A. Kurzeev; E. V. Stepanova; T. V. Fedorova; B. A. Kuznetsov; O. V. Koroleva (pp. 661-668).
Phenolic acids and flavonoids were characterized by cyclic voltammetry and total antioxidant activity in the reaction with the ABTS cation radical. Anode peak voltages (Eap) and their pH dependences were determined for the studied phenolic acids and flavonoids. The Eap and Trolox equivalent antioxidant capacity (TEAC) values were found to correlate for polyphenols, which react with the ABTS cation radical in two steps. Correlation between the half-wave potential (E1/2) and TEAC was determined for electrochemically irreversible compounds. Mechanisms of the reaction of phenolics on the electrode involving one-and two-electron oxidation are proposed.