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Applied Biochemistry and Microbiology (v.46, #5)
Structural and functional characteristics of plant NADPH oxidase: A review by A. K. Glyan’ko; A. A. Ischenko (pp. 463-471).
Data on structural and functional characteristics of plant NADPH oxidase (Rboh) are generalized. The enzyme homologs identical to the subunit gp91phox of the enzymatic complex of animal cells were found in plants. The activation of Rboh depends on the influx of Ca2+ into the cytoplasm and phosphorylation of the N-terminal region of the enzyme by Ca2+-dependent protein kinase. The possibility of the involvement of Rop GTPase, a cytosolic component of Rboh, in the activation of Rboh is discussed. It is postulated that Rboh localizes on the plasma membrane of plant cells. Rboh is activated under the influence of both biotic and abiotic factors, which is apparently associated with Ca2+ fluxes, reactive oxygen and nitrogen species, and transduction of information to the nuclear genome.
Intra- and extra-cellular flux distributions of TCA and glyoxalate cycle and vancomycin production of Amycolatopsis orientalis grown in different glycerol concentration by H. Ayar-Kayali; L. Tarhan (pp. 472-480).
The relationship between tricarboxylic acid (TCA) and glyoxalate cycle and the effect of their metabolites levels on the vancomycin production of Amycolatopsis orientalis were investigated in different concentration of glycerol (2.5–20 g/l). Intracellular glycerol levels increased with respect to increases in glycerol concentrations of the growth medium. Extracellular glycerol levels decreased slowly up to 24 h while uptake rates were increased during 36–48th h for 10 and 15 g/l and during 36–60th h at 20 g/l of glycerol. Intracellular citrate, α-ketoglutarate, fumarate levels increased up to 10 g/l glycerol concentration. However, intracellular succinate and malate levels were increased up to 15 g/l glycerol. Extracellular citrate, α-ketoglutarate, succinate and malate levels increased with respect to increases in glycerol concentration. The highest α-ketoglutarate dehydrogenase activity was determined at 15 g/l glycerol. Isocitrate lyase activity showed a positive correlation with the increases in glycerol concentration of the growth medium. Vancomycin production increased with the increases in glycerol concentration from 5 to 10 g/l. These results showed that A. orientalis grown in glycerol containing medium used glyoxalate shunt actively instead of TCA cycle which supports precursors of many amino acid which are effective on the antibiotic production.
Complete glutathione system in probiotic Lactobacillus fermentum ME-3 by T. Kullisaar; E. Songisepp; M. Aunapuu; K. Kilk; A. Arend; M. Mikelsaar; A. Rehema; M. Zilmer (pp. 481-486).
There is much information about glutathione (GSH) in eukaryotic cells, but relatively little is known about GSH in prokaryotes. Without GSH and glutathione redox cycle lactic acid bacteria (LAB) cannot protect themselves against reactive oxygen species. Previously we have shown the presence of GSH in Lactobacillus fermentum ME-3 (DSM14241). Results of this study show that probiotic L. fermentum ME-3 contains both glutathione peroxidase and glutathione reductase. We also present that L. fermentum ME-3 can transport GSH from environment and synthesize GSH. This means that it is characterized by a complete glutathione system: synthesis, uptake and redox turnover ability that makes L. fermentum ME-3 a perfect protector against oxidative stress. To our best knowledge studies on existence of the complete glutathione system in probiotic LAB strains are still absent and glutathione synthesis in them has not been demonstrated.
Hydrogen production by recombinant strains of Rhodobacter sphaeroides using a modified photosynthetic apparatus by Z. A. Eltsova; L. G. Vasilieva; A. A. Tsygankov (pp. 487-491).
Hydrogen production by recombinant strains of Rhodobacter sphaeroides pRK puf DD13 without a peripheral light-harvesting antenna complex and pRK puf ΔLM1 which is able to synthesize both antenna complexes, both of which were grown in conditions of nitrogen limitation, has been studied. The rate of hydrogen production depended on light intensity. At high cell concentration (0.91 g l−1) of pRK puf DD13, rate was maximal at 2270 W m−2 and was equal to 144.7 ml l−1 h−1 that evidences to an opportunity to increase the volume rate of hydrogen production by application of the strains with low content of pigments.
Growth peculiarities of hydrocarbon-oxidizing rhodococcus and pseudomonads dissociates in mono- and mixed cultures by E. S. Mil’ko; M. O. Maksimovich; L. I. Lopatina; E. V. Porodenko (pp. 492-496).
Growth of R-, S-, and M-dissociates of Rhodococcus rubropertinctus in mixed culture with R-, S-, and M-dissociates of Rhodococcus aeruginosa in comparison with rhodococcus monoculture cultivated on mineral nutrient medium with hexadecane has been studied. The amount of cells in the stationary growth phase has increased 10–15 times in comparison with the monoculture, and pseudomonads which dominated in population, in associations of M-dissociate of R. rubropertinctus with any dissociate of R. aeruginosa or two S-dissociates in the studied bacterial species. The emulsifying ability of the cells (maximal in R-dissociates), the synthesis of surface active compounds in pseudomonads, which is maximal in M-dissociate had the main influence on the growth of rhodococci on the nutrient medium with hydrocarbons.
Species and strain composition of microbial associations oxidizing different types of gold-bearing concentrates by T. A. Pivovarova; V. S. Melamud; E. E. Savari; G. V. Sedel’nikova; T. F. Kondrat’eva (pp. 497-504).
Quantitative abundance of microbial species within an association was found to depend on the energy substrate and the oxidation temperature of sulfide minerals. The number of microbial cells varied depending on the position of reactor in the chain, i.e., the stage of the energy substrate oxidation. Microbial associations oxidized the energy substrate more efficiently than any of their individual components. The increase in pulp density up to the solid: liquid ratio of 1: 2.5 had an unfavorable effect on microorganisms comprising microbial associations.
New biosensors for assessment of environmental toxicity based on marine luminescent bacteria by I. E. Tsybulskii; M. A. Sazykina (pp. 505-510).
Sixteen strains of luminescent bacteria of Vibrio and Photobacterium genera were isolated from water of the Azov and Black seas. Two strains prospective for biotesting were genetically identified as Vibrio fisheri V-9579 and Vibrio fisheri V-9580 according to Russian Industrial Microorganism Collection (VKMP) classification and accepted for depositing. The isolated luminescent strains exhibited high individual sensitivity to oil derived products, heavy metal salts, sodium dodecyl sulfate (SDS) and phenol (up to the maximum concentration limit for fishery impoundments). According to EC50, they are ten times more sensitive to heavy metal salts and potassium dichromate and 2–6 times more sensitive to SDS and phenol compared to P. phosphoreum (Cohn) Ford and Escherichia coli C600 (pPLS-5) strains. Using Vibrio fisheri VKMP V-9579 and Vibrio fisheri VKMP V-9580 as biosensors, we have shown their high sensitivity and efficacy to marine ecosystem toxicity assessment.
Hydrolysis of xylans by a thermostable hybrid xylanase expressed in Escherichia coli by X. Y. Weng; J. Y. Sun (pp. 511-514).
Escherichia coli-expressed a hybrid xylanase, Btx, encoded by a designed hybrid xylanase gene btx was purified. The molecular mass of the enzyme was estimated to be 22 kDa. The K m and k cat values for Btx were 1.9 mg/ml and 140 s−1, respectively. It hydrolyzed xylan principally to xylobiose and xylotriose, and was functionally similar to family 11 xylanases. As some differences were found in the hydrolytic products between birchwood xylan and wheat bran insoluble xylan, the xylan binding domains in xylanase Btx must have different effects on soluble and insoluble xylan.
β-Glycosidase of Thermus thermophilus KNOUC202: Gene and biochemical properties of the enzyme expressed in Escherichia coli by E. S. Nam; M. S. Kim; H. B. Lee; J. K. Ahn (pp. 515-524).
The β-glycosidase gene of Thermus thermophilus KNOUC202 was cloned, expressed in Escherichia coli JM109(DE3), and the enzyme was purified and characterized. The gene (KNOUC202β-gly) was composed of 1296 bp encoding a β-glycosidase (KNOUC202β-glycosidase) of 431 a.a., belonging to the family 1 of glycosyl hydrolase. The gene was expressed as monomer of 430 a.a. with amino terminal methionine excised in E. col JM109(DE3). The enzyme hydrolyzed β-glycosides whose glycone are galactose, glucose and fucose well, however showed no or very low activity on β-D-glycosides whose glycone are disaccharides and xylose. k cat of the enzyme for the hydrolysis of p-Nph-β-D-Glcp was lower than those for p-Nph-β-D-Galp and ONPG, however K m for p-Nph-β-D-Glcp was highly lower than those for p-Nph-β-D-Galp and ONPG resulting in the catalytic efficiency(k cat/K m) for the hydrolysis of p-Nph-β-D-Glcp much higher than those for p-Nph-β-D-Galp and ONPG. Optimum pH and optimum temperature of the enzyme were pH 5.4 and 90°C. The enzyme has high thermostability, not losing its activity at 80°C for 2 h in 0.05 M Na-phosphate buffer of pH 6.8 with T m of 100.0 ± 0.031°C in 0.02 M Tris-HCl buffer of pH 8.2. The b-glycosidase produced a disaccharide composed of galactose as transglycosylation by-product during hydrolysis of lactose.
The influence of medium composition on alkaloid biosynthesis by Penicillium citrinum by A. G. Kozlovsky; V. P. Zhelifonova; T. V. Antipova; N. F. Zelenkova (pp. 525-529).
The fungus P. citrinum produces secondary metabolites, clavinet ergot alkaloids (EA), and quinoline alkaloids (quinocitrinines, QA) in medium with various carbon and nitrogen sources and in the presence of iron, copper, and zinc additives. Mannitol and sucrose are most favorable for EA biosynthesis and mannitol is most favorable for QA. Maximum alkaloid production is observed on urea. Iron and copper additives in the medium containing zinc ions stimulated fungal growth but inhibited alkaloid biosynthesis. The production of these secondary metabolites does not depend on the physiological state of culture, probably due to the constitutive nature of the enzymes involved in biosynthesis of these substances.
Influence of Ca2+ ions on metabolism of active oxygen species in wheat calli cocultured with the bunt pathogen Tilletia caries by I. V. Maksimov; N. B. Troshina; O. B. Surina; E. A. Cherepanova; L. G. Yarullina (pp. 530-535).
The effect of Ca2+ on morphophysiological parameters of wheat calli (Triticum aestivum L.) infected by the bunt pathogen Tilletia caries, in particular on the level of active oxygen species, activity of oxalate oxidase, peroxidase, and catalase is investigated. The concentration of O2−, H2O2, and activity of oxidoreductases (oxalate oxidase, peroxidase, and catalase) depended on the content of Ca2+ in the culture medium of calli. The increase of the concentration of Ca2+ ions in the culture medium led to forming of calli with high structure, induction of activity of oxalate oxidase and of some isoperoxidase, and to accumulation of active oxygen species. These changes contributed to inhibition of development of the fungus. So this dependence confirm the role of calcium as the intermediant in biochemical reactions related to the formation of the protective response of plant cells to biotic stress.
Conditions of cultivation, composition, and biological activity of mycelium of Flammulina velutipes (Fr.) P. Karst by N. V. Kozhemyakina; E. P. Ananyeva; S. V. Gurina; V. A. Galynkin (pp. 536-539).
A study is made on a strain of higher basydiomycete Flammulia velutipes (Fr.) P. Karst. The conditions of maximum biomass production by Flammulia velutipes were studied. Soluble and insoluble fractions were isolated from mycelium. The composition of cultured mycelium and aqueous extracts from mycelium were investigated. These objects mainly contained carbohydrates (65.3 and 84.0% in insoluble and soluble fractions, respectively, and 56% mycelium), proteins (7.5–10.0% in fractions and 17.5% in mycelium), as well as an insignificant amount of mineral substances. The main carbohydrate component of fractions was glucose (53.6–78.8%); galactose and mannose were also present, as well as fucose and xylose in insignificant amounts. The aqueous extracts from mycelium demonstrated immunomodulating activity. They rendered a stimulating effect on the functional activity of macrophages—central cells of the reticluoendothelial system. The soluble fraction had a more pronounced effect than the insoluble fraction.
Galactomannan from the seeds of Ural licorice (Glycyrrhiza uralensis Fisch.) by D. N. Olennikov; A. V. Rokhin (pp. 540-544).
Galactomannans from the seeds of Ural licorice (Glycyrrhiza uralensis Fisch.) obtained by hot water extraction of freshly ripened (GGu-1) and overwintered (GGu-2) seeds were studied. GGu-1 and GGu-2 (yield, 1.98 and 1.99% of the seed weight) had molecular weights of 1379 and 877 kDa, respectively; their solutions were characterized by high viscosity ([η 1193.1 and 765.8 mg/g, respectively) and optical activity ([αD, +64.8 and +65.6 deg, respectively). Their galactose-to-mannose ratio was 1: 1.52 and 1: 1.50, respectively. According to IR and 13C NMR spectroscopic data and methylation analysis, the polymeric chains of GGu-1 and GGu-2 are comprised of 1,4-β-D-mannopyranose residues substituted at C-6 with single α-D-galactopyranose residues. The content of mannobiose units Man-Man, (Gal)Man-Man/Man-Man(Gal), and (Gal)Man-Man(Gal) differentially substituted with galactose in macromolecules GGu-1 and GGu-2 was 25.2, 18.4 and 55.9% for GGu-1 and 26.5, 32.5, and 41.0% for GGu-2.
Producers of mycophenolic acid in ensiled and grain feeds by A. A. Burkin; G. P. Kononenko (pp. 545-550).
Using the reaction of activated N-hydrooxisuccinimide ester of mycophenolic acid, a series of immunoreactive conjugated antigens with albumins, gelatin, and glucosoxidase is obtained. On the basis of polyclonal rabbit antibodies, a test-system for indirect competitive immunoenzyme analysis is elaborated, which has the sensitivity 0.4 ng/ml. By immunoanalysis, the ability for active biosynthesis of mycophenolic acid in strains of Byssochlamys nivea (44/44, 4100-68400 ng/ml) and Penicillium roqueforti (7/16, 204-25120 ng/ml) from the mycobiota of ensiled feeds is confirmed. The correspondence between weakly expressed producing capacity of most species of fungi of the genera Penicillium and Aspergillus prevailing in grain feeds and the data on low occurrence of this metabolite in grain (8.0%) and combined feeds (11.9%) is confirmed. A potential relationship between particular cases of a significant accumulation of mycophenolic acid (from 500 to 1500 μg/kg) in grains of wheat, corn, and combined feeds and a high biosynthetic activity in rare species P. puberulum, P. stoloniferum, and P. gladioli is discussed.
Autooxidation of a mixture of lemon essential oils, methyl linolenoate, and methyl oleinate by T. A. Misharina; M. B. Terenina; N. I. Krikunova; I. B. Medvedeva (pp. 551-556).
Stability of components of a mixture of methyl linolenoate and methyl oleinate with two lemon (Citrus limon L.) essential oils in hexane during their autooxidation in light was studied by gas chromatography. The essential oils differed by their quantitative ratio of components: the single-fold (1x) oil contained approximately 90% monoterpene hydrocarbons and 1.47% citral, whereas the proportions of hydrocarbons and citral in the tenfold (10x) oil were approximately 60 and 18.32%, respectively. The concentration and composition of essential oils influence the rates of fatty-acid oxidation and fatty-acid peroxide cleavage. The 1x lemon oil inhibited the oxidation of methyl linolenoate and methyl oleinate, whereas the 10x oil accelerated these processes. The distinctions in the resistance of the major components of lemon essential oil to oxidation, which are determined by their composition and antioxidant properties of unsaturated fatty acids, were revealed.