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.44, #5)
A review of fungal phytotoxins: from basic studies to practical use by A. O. Berestetskiy (pp. 453-465).
Recent materials are summarized, pertaining to classification of fungal phytotoxins, methods of their isolation, and assays for biological activity. Producers of phytotoxic substances have been characterized, and the chemical nature of phytotoxins has been subjected to analysis. The review gives consideration to the mechanisms of action of phytotoxins on susceptible plants and the mechanisms of plant resistance to such agents. Other matters discussed include prospects of utilizing basic knowledge of the nature and mechanisms of action of phytotoxins for (1) developing means of plant protection against diseases and weeds and (2) identifying or classifying fungi (chemosystematics).
Thymidine and thymidylate kinases from the scallop Mizuhopecten yessoensis gonads by L. L. Terent’ev; N. A. Terent’eva; V. A. Rasskazov (pp. 466-472).
Thymidine and thymidylate kinases were isolated from the gonads of scallop Mizuhopecten yessoensis. The enzymes were purified 537-and 100-fold, respectively, and were free of phosphatase and ATPase impurities. Ions of bivalent metals and ATP were necessary for both the nucleoside and nucleotide kinase activities; the pH optimum fall into the range of 7.5–8.5. KCl and NaCl at a concentration of up to 100 mM had no inhibiting effect on the activities of these scallop enzymes. Thymidine kinase catalyzed thymidine, and, at a lower rate, deoxycytidine phosphorylations did not utilize ribo-and deoxyribonucleosides, as well as pyrimidine ribonucleosides, as a phosphate acceptor. Thymidylate kinase phosphorylated TMP and dCMP with an efficiency of about 30%. In addition to ATP, these enzymes can also utilize with different efficiencies dATP, dGTP, GTP, UTP, and CTP as a donor of phosphate groups. Thymidine kinase activity was inhibited by TMP, TTP, and dCTP.
Isolation and characteristics of new thermostable DNA ligase from archaea of the genus Thermococcus by V. A. Smagin; A. V. Mardanov; E. A. Bonch-Osmolovskaya; N. V. Ravin (pp. 473-477).
The DNA ligase gene from thermophilic archaea of the genus Thermococcus (strain 1519) was identified and sequenced in the polymerase chain reaction. The recombinant enzyme LigTh1519 was expressed in Escherichia coli, purified, and characterized. LigTh1519 was capable of ligating the cohesive ends and single-strand breaks in double-stranded DNA (ATP as a cofactor). The optimum conditions for the ligase reaction appeared as follows: 100 mM NaCl, 50 mM MgCl2, pH 7.0–10.5, and temperature 70°C. More than 50% Lig1519 activity were preserved after incubation of the enzyme at 80°C for 30 min. New thermostable DNA ligase LihTh1519 may be used for basic and applied researches in molecular biology and genetic engineering.
Examination of bovine lactoferrin binding to bifidobacteria by Md. M. Rahman; W. -S. Kim; T. Ito; H. Kumura; K. Shimazaki (pp. 478-481).
In the present study, lactoferrin binding to bifidobacteria and detection of lactoferrin-binding protein in membrane fractions of several bifidobacteria have been demonstrated. This is the first report showing the binding of bovine lactoferrin to four Bifidobacterium spp. (B. infantis, B. breve, B. bifidum, and B. longum) incubated with biotinylated lactoferrin and fluorescein-conjugated avidin and observed under an inverted confocal laser scanning microscope. Fluorescence staining showed lactoferrin binding at the pole of the bacterial cells. A lactoferrin-binding protein with a molecular weight of approximately 67 kDa was also detected in the membrane fraction of Bifidobacterium spp. by far-western blotting technique using biotinylated lactoferrin and horseradish peroxidase-conjugated streptavidin. Based on the results of this and previously reported studies, we suggest that binding of lactoferrin to Bifidobacterium longum is strain dependent.
Effect of growth conditions on the molecular weight of poly-3-hydroxybutyrate produced by Azotobacter chroococcum 7B by V. L. Myshkina; D. A. Nikolaeva; T. K. Makhina; A. P. Bonartsev; G. A. Bonartseva (pp. 482-486).
It has been shown that poly-3-hydroxybutyrate (PHB) of predetermined molecular weight can be obtained by varying the growth conditions of the producer strain, Azotobacter chroococcum 7B: pH, temperature, aeration, presence of sodium acetate as an additional carbon source, or growth on crude complex carbon sources (molasses, vinasse, or starch). High-molecular-weight polymer can be obtained at pH 7.0, optimal for the culture (1485 kDa), temperature 30–37°C (1600–1450 kDa, respectively), and low aeration (2215 kDa). The following factors decrease PHB MW: pH deviation to the acidic (pH 6.0, 476 kDa) or alkaline (pH 8.0, 354 kDa) range or lower temperature (20°C, 897 kDa). Introduction of additional carbon source (sodium acetate) at concentrations in the medium varying from 0 to 5 g/l provides an original method of production of PHB with predetermined MW in a wide range, from 270 to 1515 kDa, with high PHB content in the cell.
Effect of bioprocess conditions on growth and alkaline protease production by halotolerant Bacillus licheniformis BA17 by I. E. Nikerel; Ö. Ateş; E. T. Öner (pp. 487-492).
The effect of bioprocess conditions (pH and temperature) on the growth and alkaline protease production of halotolerant Bacillus licheniformis BA17 bioreactor cultures have been systematically analyzed using response surface methodology in order to assess the importance of these generally disregarded parameters. Two models were proposed differing by the choice of response variable. Under optimized bioprocess conditions, whole alkaline protease activity was about 3 fold higher than the activities obtained in the preliminary studies. Results of this study not only highlight the importance of pH and temperature for further engineering purposes but also serve as basis for understanding the true mechanism lying under the relation between these process parameters and growth and whole alkaline protease production.
Sequential degradation of p-cresol by photochemical and biological methods by E. A. Karetnikova; O. N. Chaikovskaya; I. V. Sokolova; L. I. Nikitina (pp. 493-501).
Sequential photo-and biodegradation of p-cresol was studied using a mercury lamp, as well as KrCl and XeCl excilamps. Preirradiation of p-cresol at a concentration of 10−4 M did not affect the rate of its subsequent biodegradation. An increase in the concentration of p-cresol to 10−3 M and in the duration preliminary UV irradiation inhibited subsequent biodegradation. Biodegradation of p-cresol was accompanied by the formation of a product with a fluorescence maximum at 365 nm (λex = 280 nm), and photodegradation yielded a compound fluorescing at 400 nm (λex = 330 nm). Sequential UV and biodegradation led to the appearance of bands in the fluorescence spectra that were ascribed to p-cresol and its photolysis products. It was shown that sequential use of biological and photochemical degradation results in degradation of not only the initial toxicant but also the metabolites formed during its biodegradation.
Isolation of an aboriginal bacterial community capable of utilizing cyanide, thiocyanate, and ammonia from metallurgical plant wastewater by N. V. Grigor’eva; Yu. V. Smirnova; S. V. Terekhova; G. I. Karavaiko (pp. 502-506).
An aboriginal bacterial community capable of degrading cyanide (10 mg/l) and thiocyanate (2 g/l) and eliminating ammonia (120 mg/l) had been isolated from recycled water samples after blast-furnace gas purification of a metallurgical plant wastewater. It was shown that the optimal conditions for this bacterial community were as follows: temperature, 34°C; pH, 8.8–9.0; available organic matter concentration (glucose equivalent), 5 g/l; and dissolved O2 concentration, 8–10 mg/l. This aboriginal community was formed by the bacteria belonging to the genus Pseudomonas.
Effect of acidic treatment of the chemical composition and bacterial oxidation of arsenic-bearing gold concentrate by N. V. Fomchenko; T. A. Pivovarova; T. F. Kondratyeva (pp. 507-511).
Effect of acidic pretreatment of arsenic-bearing gold concentrate, a promising gold source, on its chemical composition and efficiency of its bacterial oxidation (BO) was studied. The titer of sulfobacilli during BO of the concentrate after high-temperature acidic treatment was 9.0 × 107 cells/ml, the degree of arsenic sulfide oxidation being 71.1%, and in the control, 6.5 × 107 cells/ml with the oxidation degree as low as 48.7%. Deeper oxidation of the main gold-containing mineral, arsenic sulfide, would allow more efficient gold recovery from the concentrate.
Kinetic aspects of inhibition of the phytopathogenic fungi growth by rhizosphere bacteria by O. M. Minaeva; E. L. Akimova; E. V. Evdokimov (pp. 512-517).
Kinetics of growth inhibition of fungi Fusarium and Bipolaris caused by bacteria Pseudomonas sp. V-6798 and Azotobacter chroococum V-2272 D on dense nutrient media, both in single-crop system and by coinoculation, was demonstrated. The speed of fungal colonies growth as a function of bacteria concentration in inoculate was shown to be in accordance with the Ierysalimskii modified equation. The degree of antagonistic activity was suggested to be assessed by the constant of inhibition (K i ) and residual rate of fungi growth. Constant of inhibition of fungal growth by bacteria varied within 10–100 cells/ml for observed species. More effective fungistatic influence of bacterial strains in combined culture was observed. Parameters reported in the present study allow comparing the degree of bacteria antifungal activity in vitro. Suggested screening method could be used for selection of bacteria as activity biofungicide and while selecting biomedication for defined plant pathogen disruption.
Regulatory effect of microbial alkyloxybenzenes of different structure on the stress response of yeast by I. A. Konanykhina; E. F. Shanenko; N. G. Loiko; Yu. A. Nikolaev; G. I. El-Registan (pp. 518-522).
The effect of alkylhydroxybenzenes (AHBs) belonging to the class of alkylresorcinols differing in the degree of hydrophobicity—C7-AHB and more hydrophobic C12-AHB—on the resistance of Saccharomyces cerevisiae cells to heat shock and oxidative stress of lethal intensity was studied. Depending on structure and concentration, AHB added 2 h before exposure to stress had either an antistress or stress-potentiating effect on yeast cells in the mid-logarithmic growth phase. C7-AHB at concentrations 0.25–0.5 g/l caused a two-to fivefold increase in the resistance of yeast cells to hydrogen peroxide (30–150 mM), whereas C12-AHB reduced it at all concentrations. C7-AHB and C12-AHB had a similar effect on yeast subjected to heat shock (45°C, 30 min). It was found that the degree of the protective effect of C7-AHB and potentiating effect of C12-AHB depended on the nature of the stressor, being more pronounced in heat shock. The environmental significance of the antistress and stress-potentiating effects of microbial AHBs is discussed.
Lipids of filamentous fungi as a material for producing biodiesel fuel by Ya. E. Sergeeva; L. A. Galanina; D. A. Andrianova; E. P. Feofilova (pp. 523-527).
Species of various filamentous fungus taxa were tested for ability to produce lipids suitable as a material for manufacturing biodiesel. The mucoralean fungus Cunninghamella japonica was found to be a promising lipid producer. The inexpensive medium for its growth developed in this study contained ammonium nitrate as a nitrogen source. With its use, up to 16 g/l biomass and over 7 g/l lipids was obtained. The fungal lipids were dominated by oleic acid. It constituted 50% of total fatty acids. The iodine index of the lipid fraction was 86.61. The heat of combustion of the lipids, 37.13 MJ/kg, was close to the value for rapeseed oil.
Increased secretion of lignolytic enzymes by the Lentinus tigrinus fungus after addition of butanol and toluene in submerged cultivation by D. A. Kadimaliev; O. S. Nadezhina; N. A. Atykyan; V. V. Revin; A. A. Parshin; A. I. Lavrova; P. V. Dukhovskis (pp. 528-534).
We studied the effects of butanol and toluene on secretion of lignolytic enzymes by the Lentinus tigrinus fungus during submerged cultivation. Addition of butanol and toluene during the trophophase was followed by an increase in laccase and peroxidase activity of the culture and change in the composition of phospholipids and fatty acids. The ratio of phosphatidylcholine and phosphatidic acid decreased, while the amount of lysophosphatidylcholine, phosphatidylethanolamine, phosphoinositides, phosphatidylserine, and unsaturated fatty acids decreased. These changes resulted in an increase in the unsaturation index.
Primary and secondary metabolism of winter wheat under cold hardening and treatment with antioxidants by N. A. Olenichenko; N. V. Zagoskina; N. V. Astakhova; T. I. Trunova; Yu. V. Kuznetsov (pp. 535-540).
The content of saccharides and phenolic compounds (including flavonoids and lignin) and the activity of L-phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were determined in leaves and tillering nodes of winter wheat Triticum aestivum L.) cultivars Inna and Moskovskaya 39, differing in the level of frost resistance. These parameters were determined in three groups of plants—control, hardened, and treated with synthetic antioxidants (ambiol and amerol 2000). Cold hardening increased accumulation of primary and secondary metabolites in tissues but decreased the enzyme activity. Treatment with antioxidants also increased the content of saccharides and phenolic compounds (primarily flavonoids) and PAL activity. These changes were more pronounced in cultivar Inna, which is less frost resistant than Moskovskaya 39.
Immunochemical properties of conjugated antigens from N-substituted phenothiazines and dibenzazepines with antiarrhythmic activity by A. A. Burkin; M. A. Burkin (pp. 541-544).
The use of metabolites of antiarrhythmic drugs (ethmozine, ethacizine, and bonnecor) as haptens in the synthesis of conjugated antigens allowed us to induce the formation of antibodies with different specificity for certain metabolites. A new enzyme immunoassay was developed for the detection of phenothiazine and dibenzazepine derivatives (ethmozine, ethacizine, and bonnecor). Nanogram and subnanogram quantities of these substances may be detected in biological fluids.
The influence of starter cultures on the formation of volatile compounds in dry smoked sausages by T. A. Misharina; M. B. Terenina; N. I. Krikunova; I. A. Khankhalaeva; I. S. Khamagaeva; L. L. Nikiforova (pp. 545-550).
The differences between the composition of volatile substances in two specimens of dry smoked sausages produced using a standard and experimental (a mixture of propionic acid bacteria and bifidobacteria) cultures were studied by capillary gas chromatography. It was found that the experimental starter culture intensified the flavor-formation processes as compared with the standard culture. The experimental specimen had richer qualitative and quantitative compositions and displayed more intensive aroma and flavor. The contents of lactones and volatile terpenoids in the experimental specimen were much higher than in the control. The organoleptic characteristics of experimental dry smoked sausage specimen were considerably better.
Obtaining and study of monosaccharide derivatives of low-molecular-weight chitosan by A. V. Il’ina; S. N. Kulikov; G. I. Chalenko; N. G. Gerasimova; V. P. Varlamov (pp. 551-558).
The possibility of obtaining monosaccharide derivatives of low-molecular-weight chitosan with the use of the Maillard reaction was studied. Chitosan derivatives (molecular weight, 24 and 5 kDa) obtained with glucosamine, N-acetyl galactosamine, galactose, and mannose with a substitution degree of 4–14% and a yield of 60–80% were obtained. Some physicochemical and biological properties of these derivatives were studied. We showed that monosaccharide derivatives of low-molecular-weight chitosan exhibited antibacterial activity. Chitosan at a concentration of 0.01% caused 100% death of bacteria B. subtilis and E. coli. The strongest antibacterial effect was exhibited by 24-kDa derivatives: only 0.02–0.08% of cells survived. These derivatives were two orders of magnitude more effective than the 5-kDa chitosan modified with galactose.
OECD Best Practice Guidelines for Biological Resource Centers. OECD, 2007, 115 p. by S. M. Ozerskaya (pp. 559-560).
The book is the first published collection of guidelines regulating operational activities of biological resource centers, approved by representatives of the 30 member nations of the Organization for Economic Cooperation and Development (OECD). The published standards were prepared as a result of multiple discussions held by expert groups of the OECD members, together with key experts of partner nations, under the auspices of a specialist task force established by the OECD Working Party on Biotechnology.