Vol 53, No 1 (2017)

It was shown that the alkaline phosphatase (AP) isolated from eggs of the sea urchin Strongylocentrotus intermedius was a homodimer with a molecular mass of 150 kDa and that it exhibited maximal activity at a рН of 8.1–8.5 and a temperature of 45°С. Mg²⁺, Ca²⁺, and Mn²⁺ ions, as well as DTT, are activators of AP activity, while Zn²⁺, Cu²⁺, Cd²⁺, Pb²⁺, and Ni²⁺ ions, as well as EDTA, N-EMI, and p-CMB, inhibit its activity. The enzyme demonstrates unique salt resistance and can hydrolyze the substrate in seawater. It was shown by fluorescence methods and circular dichroism that an increase of the NaCl concentration above 1.0М caused noticeable changes in the secondary and tertiary structures of the protein and a decrease in enzyme activity. Analysis of the molecular masses of tryptic peptides conducted by mass spectrometry with the MASCOT program (which is based on the NCBI and SWISS-PROT databases) did not allow identification of the investigated protein. The uniqueness of the source and of the properties of the investigated AP, which were not characteristic for nonspecific AP, as well as the difficulties in primary structure identification with the fingerprinting technique, suggested that this enzyme was a nontypical AP with a novel structure.

The intensity of free radical processes, activity of antioxidant enzymes (superoxide dismutase, catalase), and the content of low molecular weight antioxidants (reduced glutathione, citrate) in skeletal muscle and liver from rats with experimental rheumatoid arthritis administered with biguanide synthetic derivatives (2,4-dicarbomethoxyphenyl-biguanide and 4-methyl-phenyl biguanide) selected by Prediction of Activity Spectra for Substances (PASS), a computer program for the prediction of biological activity, were studied. The observed changes in the studied parameters toward the reference values under the effect of tested compounds can be explained by their antioxidant and protective properties during pathology, which are accompanied by oxidative stress. The results can be used for the development of new methods for the prevention and treatment of rheumatoid arthritis.

The effect of culture conditions (nutrient media, aeration, and temperature) of Staphylococcus warneri KL-1 on the growth and production of the antibacterial peptide warnerin was studied. The selected medium allowed the intensive development of S. warnerin KL-1 culture and a high level of peptide accumulation. It was demonstrated that the bacterial culture growth rate and warnerin production depended on the extent of aeration of the nutrient medium. The highest antibacterial activity (ABA) was achieved in culture liquid by the fed-batch cultivation. The amino acid sequence of the warnerin pure form was determined by structural bioinformatics analysis, and the 3D structure of this peptide was constructed. It was found that the peptide molecule contained three thioether cycles formed by one lanthionine residue and two methyl-lanthionine residues. According to the current classification of lanthipeptides, warnerin can be attributed to class I of lantibiotics.

The ability of representatives of various species of the bacterial genus Azotobacter (A. chroococcum 7B, A. chroococcum 12B, A. chroococcum 12BS, A. agile 12, A. indicum 8, A. vinelandii 17, and A. vinelandii 5B) to alginate synthesis has been studied. It has been shown that all tested bacterial strains have this ability to different extents. Capsular alginate comprises from 2.6 to 32% of the total amount of synthesized alginate in various bacterial species. Strains that are able to active synthesis of alginate have been selected; the effect of the medium composition on their biosynthesis has been studied. The optimal conditions for alginate synthesis by the A. chroococcum 12BS producer strain include the presence of mannitol (40 g/L), yeast extract (1%), and low concentration of phosphates (KH₂PO₄—0.008 g/L, K₂HPO₄—0.032 g/L) in the medium; alginate production under these conditions is 4.5 g/L. The effect of aeration on polymer biosynthesis has been revealed: an increase in aeration causes an increase in alginate synthesis, while its decrease promotes the synthesis of poly-3-hydroxybutirate. It has been shown by IR spectroscopy that alginates obtained under various conditions of cultivation contain different ratios of residues of mannuronic and guluronic acids (M/G from 70/30 to 80/20) in the polymer chain and also differ in the amount of acetyl groups (from 10 to 25%) in the polyme structure.

Six strains of oil-degrading bacteria isolated from the endosphere and rhizosphere of plants growing on oil polluted soils of the Irkutsk region were studied to determine the pathways for biodestruction of polyaromatic oil hydrocarbons. All strains were able to efficiently degrade polyaromatic hydrocarbons with the formation of pyrocatechin as a final product; strains 90, 108, and 112 additionally formed protocathechuic acid. The culture broth of the studied strains contained ferulic, n-coumaric, n-oxybenzoic, vanillic, and lilac acids, which probably represent metabolites of cinnamic alcohol, cinnamic aldehyde, and benzoic acid presenting in oil and metabolized by bacteria.

Mathematical modeling of the biotechnology for the removal of ammonium nitrogen from wastewater based on the anammox process was performed with the specialized BioWin software suite (EnviroSim Associates Ltd., Canada). Nitrogen removal by means of the transformation of ammonium nitrogen to molecular nitrogen was conducted in a continuous stirred bioreactor carrying both suspended and immobilized activated sludge. Both basic values of the kinetic and stoichiometric coefficients are incorporated in the BioWin software, and those that changed based on the results of the experimental studies were used for the calculations. The optimal temperature and dissolved oxygen concentration revealed by mathematical modeling were 35°C and 0.14 mg/L. The results obtained from calculations were similar to those obtained in the experiments. The calculated and experimental concentrations of ammonium, nitrites, and nitrates in the treated water were similar and comprised 10.7 and 11.7% of the initial concentration entering the bioreactor, respectively. The selected mathematical model possessed a high predictive ability for the calculation of biotechnologies based on the anammox process

As the demand for biofuels for transportation is increasing, it is necessary to acquire technologies that will allow affordable production of biodiesel. Conventional biodiesel is mainly produced from vegetable oil by chemical transesterification, but this product has relatively low yield and is competing with agricultural land that can be used for food production. In the present study, 14 filamentous fungi were isolated from different types of soil from Al-Hassa, Saudi Arabia. Nile red staining revealed that lipid bodies were present in 6 of the 14 fungal isolates. Lipid extraction showed that 3 fungi were able to accumulate lipid >20% (wt/wt) of their dry cell mass (0.59–2.40 g/L). The profile of fatty acids revealed a high content of oleic (C18:1, n9), palmitic (C16:0) and linoleic (C18:2) acids similar to conventional vegetable oils used for biodiesel production. Isolate RY4, with the highest lipid yield was identified as Mucor circinelloides based on morphological characteristics confirmed with 18S rRNA gene sequencing. Sequence data of nucleotides were obtained from DNA sequencing submitted to GenBank [GenBank: AB916546.1]. Certain oil compounds were determined by FTIR spectroscopy.

In this study, we developed a microplate sandwich analysis of Escherichia coli and Staphylococcus aureus bacterial pathogens based on the interaction of their cell wall carbohydrates with natural receptors called lectins. An immobilized lectin-cell-biotinylated lectin complex was formed in this assay. Here, we studied the binding specificity of several plant lectins to E. coli and S. aureus cells, and pairs characterized by high-affinity interactions were selected for the assay. Wheat germ agglutinin and Ricinus communis agglutinin were used to develop enzyme-linked lectinosorbent assays for E. coli and S. aureus cells with the detection limits of 4 × 10⁶ and 5 × 10⁵ cells/mL, respectively. Comparison of the enzyme-linked immonosorbent assay and the enzyme-linked lectinosorbent assay demonstrated no significant differences in detection limit values for E. coli. Due to the accessibility and universality of lectin reagents, the proposed approach is a promising tool for the control of a wide range of bacterial pathogens.

The effect of carbon nanomaterials (carbon nanotubes, thermally expanded and pyrolytic graphite) on the bioelectrochemical activity of Gluconobacter oxydans bacterial cells was studied during sorption contact with nanomaterials. For bacterial immobilization, the surface of a working bioelectrode was modified via the application of bacterial suspension in the studied nanomaterial and chitosan. The bioelectrochemical electrode characteristics (the amplitude of generated potential, cyclic volt–ampere characteristics, resistance) were estimated before and in the process of bacterial interaction with ethanol (3-electrode measurement scheme). Modification of the spectral graphite electrode by carbon nanotubes allowed a decrease in the resistance of the charge transfer by 48% and an increase in the oxidation current on cyclic volt—ampere characteristics at a voltage of 200 mV by 21% as compared with nonmodified electrode. The thermally expanded and pyrolytic graphite increased the bioelectrode resistance to 4050 and 8447 Ohm cm², respectively. Mathematical modeling demonstrated that from 75 to 100% of biomaterial (depending on the used nanomaterial) were involved in the process of electricity generation with the selected method of the bacterial immobilization. The use of data obtained during the development of microbial biosensors and electrodes of biofuel cells is discussed.