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.45, #3)
The aerobic degradation of dichloromethane: Structural-functional aspects (a review) by Yu. A. Trotsenko; M. L. Torgonskaya (pp. 233-247).
This review summarizes current notions on the mechanisms of transport and degradation of dichloromethane (DCM) by aerobic methylotrophic bacteria as well as enzymological and genetic aspects of DCM dehalogenation, including probable pathways used by cells to overcome accompanying stresses (acid, osmotic, and oxidative). The topicality of the problem of the degradation of this genotoxic solvent is associated with the search for and creation of new DCM-destroying strains, which would provide for more efficient bioremediation of industrial sewage and ecosystems with extreme pH and salinity and could be used for the development of modern techniques for DCM degradation on the basis of existing strains. Special attention is given to the consideration of methodological approaches to the interpretation of physiological—biochemical and molecular bases of adaptation of bacteria to the utilization of DCM and other halogenated pollutants.
Effect of salts and Triton X-100 on ultrafiltration purification and properties of extracellular glucose oxidase from Penicillium adametzii LF F-2044.1 by A. N. Eryomin; L. A. Zhukovskaya; R. V. Mikhailova (pp. 248-257).
We compared the effectiveness of glucose oxidase isolation from the culture fluid of Penicillium adametzii LF F-2044.1 in the presence of ammonium sulfate, ammonium chloride, and Triton X-100. Ammonium chloride inhibited glucose oxidase in the culture fluid. This compound increased K M (by 1.2–1.3 times), but decreased V max for D-glucose oxidation (by 1.7–1.8 times). Ammonium sulfate had little effect on kinetic parameters. Combined treatment with salts and Triton X-100 was followed by a significant increase in the effectiveness of ultrafiltration purification of the culture fluid. The samples of glucose oxidase were electrophoretically characterized. The dependence of kinetic parameters on glucose oxidase concentration during oxidation of D-glucose was evaluated. The catalytic constant and k cat/K M ratio for glucose oxidase samples from the culture fluid isolated in the presence of additives significantly surpassed those for enzyme samples, which were obtained by ultrafiltration of the culture fluid with no additives and chromatography on aluminum oxide. The activity of glucose oxidase isolated from the culture fluid in the presence of ammonium chloride was lower compared to that of the enzyme obtained in the presence of ammonium sulfate. This agent is preferable for ultrafiltration of the culture fluid.
The properties of invertase, covalently immobilized at activated carbon by D. T. Mirzarakhmetova; D. B. Dekhkonov; M. M. Rakhimov; S. Kh. Abdurazakova; Z. R. Akhmedova (pp. 258-261).
The covalent immobilization of yeast invertase with glutaraldehyde at activated carbon, modified preliminarily by urea and dimethyl formamide treatment, has been established. Some physicochemical properties of the immobilized and native enzyme in water and water-organic solutions have been studied. Hydrolytic, as well as transferase enzyme characteristics have changed after immobilization. The optimal conditions for hydrolytic and transferase activity of immobilized invertase are pH 6.0 and 7.0, respectively. The optimum temperature for the immobilized enzyme is 30°C. The conversion degree of isoamyl alcohol depends on the substrate and enzyme concentrations in medium, holdup time and organic phase quantity in the reaction medium.
The synthesis of nucleic acids in cultivated Polyscias filicifolia cells exposed to oxidative stress by N. V. Kirillova; A. I. Spasenkov; O. M. Spasenkova; M. A. Strelkova (pp. 262-265).
The content of nucleic acids in the cell culture of fern-leaf aralia Polyscias filicifolia (Moore ex Fournter) Bailey (Araliaceae) exposed to heat shock (3 h at 45°C) decreased significantly (by 20–30%). The decrease in DNA and RNA contents was even larger (30–40%) after longer heat shock (24 h). Cold (24 h at 7°C) caused an even more dramatic decrease in DNA (by 34.2%) and total RNA (by 48%) contents. To judge from the DNA production rate, the presence of hydrogen peroxide and phenazine methosulfate in the culture exerted a dose-dependent and differently directed action on cell proliferation.
Isolation and characterization of bacteriocin-like inhibitory substances from lactic acid bacteria isolated from Azerbaijan cheeses by S. G. Gulahmadov; N. F. Abdullaeva; N. F. Guseinova; A. A. Kuliev; I. V. Ivanova; M. Dalgalarondo; J. -M. Chobert; T. Haertlée (pp. 266-271).
The search for lactic acid bacteria (LAB) producing bacteriocin-like inhibitory substances (BLISs) was performed in traditional Azerbaijan cheeses. Eight strains have been isolated and identified, four of which (S1a, S2, Q2b, and M1b) were identified as Lactobacillus buchneri. The remaining four strains (M3a, A4b, Q4a, and A3) were identified as L. pentosus, L. brevis, L. fermentum, and L. collinoides, respectively. Antimicrobial agents of all isolated LAB strains suppressed the growth of Lactobacillus bulgaricus 340, Escherichia coli, Enterococcus durans, and Listeria innocua. Saccharomyces cerevisiae and Candida pseudotropicalis were resistant to these BLISs. Proteinase K and trypsin completely inactivated BLIS whereas lipase and amylase partially inactivated BLIS.
The influence of conditions of Acinetobacter calcoaceticus K-4 strain cultivation on surface-active substances synthesis by T. P. Pirog; S. I. Antonyuk; Ye. V. Karpenko; T. A. Shevchuk (pp. 272-278).
It has been observed that the Acinetobacter calcoaceticus K-4 strain produces surface-active substances (SAS) while growing either on hydrophilic (ethanol) or on hydrophobic substrates (hexadecane). Maximal SAS synthesis (with a conditional SAS concentration of 3.6; emulsifying activity of culture liquid dissolved in 50 times equal to 96%) was detected with growth on an ethanol-containing medium with the addition of urea, yeast autolysate and microelements, C/N ratio 60:1 and 10% inoculate, cultivated on ethanol-containing medium by the end of the exponential phase of growth. With respect to its chemical nature, extracellular SAS synthesized by A. calcoaceticus K-4 growing on ethanol-containing medium under optimal cultivating conditions form a glycolipid-aminolipid complex.
Phosphate-mobilizing bacteria Bacillus subtilis as phenolic producers by L. S. Tserkovniak; I. K. Kurdish (pp. 279-284).
Bacteria Bacillus subtilis IMVV-7023 accumulate biologically active phenolic substances in the culture liquid. They include significant amounts of phenylacetic (29.03%) and 4-hydroxyphenylacetic (10.49%) acids. These acids can induce root formation in plants. They also suppress fungal plant pathogens.
Physiology-biochemical properties of the cyanobacterium Oscillatoria deflexa by I. V. Gribovskaya; G. S. Kalacheva; Yu. I. Bayanova; A. A. Kolmakova (pp. 285-290).
The optimal cultivation conditions for the cyanobacterium Oscillatoria deflexa were studied: temperature (25–27°C), pH (9.0–11.0), and illumination (7 klx). A nutrient medium providing for optimum cyanobacterium growth was selected, as well as media containing an aqueous extract of human urine ash and an inedible material of wheat and vegetables with added nitrates and bicarbonate. The chemical composition (macro and microelements, content of proteins, lipids, carbohydrates, and vitamins, amino acid and fatty acid composition, ash residue) of O. deflexe was studied for the first time. An analysis of the results indicates that O. deflexa is not inferior to the cyanobacterium Spirulina platensis and the green laver Chlorella vulgaris in practical use, for its mineral composition, content of vitamins, essential amino acids and fatty acids, and exceed them in its content of vitamin E and microelements, such as Fe, Mn, Ni. The bacterium’s ability to transport NaCl up to 30 g/l within the medium was studied, and its unique ability for survival and long-term storage was shown. The enhibitory effect of the biomass of O. deflexa on the germination of wheat grains, and growth of daphnids and rotifers was shown.
Effect of the synthetic polysaccharide MOD-19 on the formation and function of symbiosis between Pisum sativum L. and Rhizobium leguminosarum bv. viciae by E. D. Krugova; S. Ya. Kots; N. M. Mandrovskaya (pp. 291-296).
The physiological action of the MOD-19 polysaccharide (PS), synthesized similarly to bacterial glucans, on the nodule bacteria Rhizobium leguminosarum bv. viciae and pea seeds was studied. It was found that MOD-19 stimulated nodule bacterium growth and bacterial biomass accumulation. It also altered metabolism in rhizobia grown in solid and liquid media containing this polymer. Treatment of pea seeds with MOD-19 before sowing increased the intensity of root formation, plant tissue peroxidase activity, and general symbiosis efficiency owing to secondary nodule formation on lateral roots and prolongation of their intense nitrogen fixation.
Effect of legume seed exudates on the formation of Rhizobium-legume symbiosis by N. N. Mel’nikova; S. V. Omel’chuk (pp. 297-302).
The effect of exudates from germinating lupine and soybean seeds on the development of legumerhizobia symbiosis in the same plants was studied. Treatment with the exudates increased the nodulation activity of Bradyrhizobium sp. (Lupinus) and slowed down the formation of nodules by Bradyrhizobium japonicum 634b. The number of nodules produced by B. japonicum 631 on soybean roots increased when the strain was treated with soybean exudate at a lower concentration. The exudates differently affected nodulation on the primary and secondary roots of the host plant. The formation of symbiosis by B. japonicum 631 incubated with legume seed exudates increased the weight of the green parts of plants at the bud stage.
Promotional mechanism of high glycerol productivity in the aerobic batch fermentation of Candida glycerinogenes after feeding several amino acids by T. Xie; H. Y. Fang; B. Zhuge; J. Zhuge (pp. 303-308).
To disclose the addition of some strong promotional amino acids (namely glycine, glutamate, lysine and aspartic acid) is how to improve the glycerol productivity of Candida glycerinogenes. An amino acid addition strategy based on dynamic enzyme activity was applied to improve glycerol productivity and decrease the byproducts formation in a fermentation of C. glycerinogenes in a 7-1 bioreactor. Compared with the control, after feeding glycine, glutamate, lysine and aspartic acid, glycerol productivity obtained an increase of 22.3, 25.6, 23.5 and 28.6%, respectively; meanwhile, the amounts of ethanol, acetic acid and pyruvate decreased largely. Whichever glycine, lysine, glutamate or aspartic acid was fed could elevate the activities of glucose-6-phosphate dehydrogenase (G6PDH), citrate synthase (CIT), triosephosphate isomerase (TPI) and cytoplasmic NAD+AEAAKw-dependent glycerol-3-phosphate dehydrogenase (ctGPD), and reduce the activities of pyruvate kinase (PYK), phosphofructokinase (PFK) and alcohol dehydrogenase (ADH). The reason of glycerol overproduction by the yeasts after feeding glycine, glutamate, lysine or aspartic acid is that the anaplerosis of intermediate metabolites in TCA cycle for amino acid degradation can decrease the flux from Embden-Meyerhof-Parnas (EMP) pathway to TCA cycle and enhance the flux through glycerol biosynthesis pathway. Above all, not only the high active hexose monophosphate (HMP) pathway but also the high dihydroxyacetone phosphate (DHAP) level plays an important role in the high glycerol productivity of C. glycerinogenes. The strategy of amino acid supplement is significant and can be economically implemented by an online process control strategy for higher yield of glycerol in industrial scale.
Coupling recovery strategy of cellulase in hydrolyzate after hydrolysis with Tannin flocculation and PEG desorption by J. Xu; H. Chen (pp. 309-312).
Through determination of cellulase in terms of protein content in the hydrolyzate after hydrolysis, it was found that 50.15–67.21% of the originally added protein was still remained in the hydrolyzate. Tannin flocculation followed by PEG desorption was coupled to recover this portion of cellulase. About 94.99% of the protein in the hydrolyzate was precipitated into Tannin-cellulase compound under tannin concentration of 5% (w/v) with pH 5.0 and NaCl concentration of 1.0%. In order to desorb cellulase from Tannin-cellulase compound, PEG 6000 was employed as a desorbent. The recovered enzyme activity reached 133.25% when the PEG concentration was 1.5% (w/v). This, to some extent, indicated that PEG was also an effective activator of cellulase. The article is published in the original.
Isolation of the chitin-glucan complex from the fruiting bodies of mycothallus by T. N. Ivshina; S. D. Artamonova; V. P. Ivshin; F. F. Sharnina (pp. 313-318).
A four-stage procedure for the isolation of the ChGC from the biomass of natural fungi—the honey mushroom (Armillariella mellea) and the yellow morel (Morchella esculenta), belonging to the classes Basidiomycetes and Ascomycetes, respectively, has been developed. The isolation procedure included deproteinization (2% NaOH + 0.1% sodium stearate, 83–85°C, 2 h), demineralization (1% HCl, 55–60°C, 2 h), depigmentation (5% H2O2 in ammonia (30–35°C, 4 h)), and deglucanization (2% NaOH, 83–85°C, 2 h). The original raw material and the chitin-containing materials were characterized on the basis of results of Fourier transform infrared spectroscopy, X-ray analysis, and pyrolytic gas chromatography using crustacean chitin as a reference compound. The content of chitin in the final products was 70% for A. mellea and 50% for M. esculenta. The possibility of obtaining chitin-containing materials with the required properties by selecting the fungal species and treatment conditions (the succession and repetition of certain stages) is demonstrated.
The plastid machinery of apical meristematic cells of potato tubers whose growth is regulated by melaphene by T. A. Platonova; A. S. Evsyunina; N. P. Korableva (pp. 319-325).
A comparative ultramorphometric study of the plastid machinery of apical meristematic cells of potato (Solanum tuberosum L.) tubers in a normal state (during sprouting) and under treatment with melaphene, a growth regulator of a new generation, at a growth-stimulating concentration was performed. The area of the plastid machinery of cells was found to increase under the effect of melaphene. A stimulatory effect of melaphene on starch accumulation and development of peripheral plastid reticulum in leucoplasts of apical meristematic cells of potato tubers was discovered.
Antigen-binding activity, structural characteristics and use of monoclonal antibodies to human alpha-1-microglobulin by T. S. Serchenya; A. G. Pryadko; O. V. Sviridov (pp. 326-333).
Four monoclonal antibodies (mAbs), G6, F9, H8, and B2, against human alpha-1-microglobulin (A1M) have been produced and characterized. The parameters of affinity (Kp ∼ 109 M−1), epitope specificity (the additively binding G6/F9, G6/H8, G6/B2, F9/H8, and F9/B2 pairs), and the observed effect of reversibility of structural changes induced by chemical agents allow use of these mAbs in biospecific methods of A1M purification and quantitative determination. The application of mAbs to an A1M enzyme immunoassay (analytical sensitivity—0.5 μg/l) and one step isolation of pure A1M by immunoaffinity chromatography was described.
Immunoaffinity chromatography of human thyroid peroxidase: The stability of the three-dimensional structure and immunoreactivity of antigen and antibodies under various elution conditions by E. P. Kiselyova; O. V. Tsyganova; I. I. Vashkevich; O. V. Sviridov (pp. 334-342).
Actions of various chemical agents modeling immunoaffinity chromatography elution conditions caused structural changes of the components of human thyroid peroxidase (TPO) complexes with monoclonal antibodies (MABs) F8 and A1 whose antigenic determinants have a conformational nature and are located in the immunodominant region and a peripheral region of TPO, respectively. These changes became apparent in the circular dichroism and fluorescence spectra of TPO and both MABs as well as in the immunoassay. The effectiveness of the chemical reagents with respect to TPO desorption from an immobilized MAB decreased in the following order: 0.2 M ammonia (pH 11.5) > 0.1 M lithium 3,5-diiodosalycilate > 0.1 M glycine-HCl (pH 2.5) > 1 M NaI > 30% propylene glycol + 1 M NaCl > 30% propylene glycol > 1 M NaCl. At pH 11.5, the three-dimensional structure and immunoreactivity of TPO retained completely and only minor alterations of MAB analogical parameters took place, thus providing a high yield of the functional active human TPO and favoring repeated use of the immobilized MABs in immunoaffinity chromatography. The results may be used as a strategy for the optimization of various protein antigens immunoaffinity chromatography.
The isolation of immunoglobulin G and albumin protein standards and the study of their oligomerization and antigenity during storage in saturated ammonium sulfate solution by A. K. Barsukov; A. V. Barmin; A. I. Kuznetsov; O. Yu. Nesterova; S. A. Ushnurtseva; A. N. Panin; V. I. Smolenskii; V. I. Ulasov; V. L. Sviderskii; A. E. Khovanskikh (pp. 343-348).
The feasibility of the isolation and purification of immunoglobulin (Ig) G and albumin from human and animal blood serum by means of a uniform laboratory technique using non-chromatographic and chromatographic fractionating stages is demonstrated. The oligomerization of these proteins when stored in strong solutions of ammonium sulfate is revealed. It was ascertained that storage in sulfate suspension did not cause the fragmentation of IgG and albumin, and the degree of protein oligomerization up to 3% had no effect on the sensibility of the immunoferment assay.
Yu. A. Trotsenko and V. N. Khmelenina, Ekstremofil’nye metanotrofy (Extremophilic Methanotrophs), Pushchino: ONTI PNTs RAN, 2008, 206 p.
by T. V. Tikhonova (pp. 349-350).