Some aspects of general characteristic and classification of bacterial β-lactamases

Наведено дані стосовно основних структурних і функціональних груп бактеріальних β-лактамаз, а також сучасні системи класифікації β-лактамаз, які ґрунтуються на спектрах активності, чутливості до інгібіторів і особливостях молекулярної структури. Показано найважливіші властивості β-лактамаз: субстратна специфічність, чутливість до дії інгібіторів, особливості генетичної детермінації. Особливу увагу приділено β-лактамазам грамнегативних бактерій ТEM-, SHV-типу, їх ролі у формуванні стійкості до різних β-лактамів. Приведены данные относительно основных структурных и функциональных групп бактериальных β-лактамаз. Описаны современные системы классификации β-лактамаз, которые базируются на спектрах активности, чувствительности к ингибиторам и особенностях молекулярной струк­туры. Представлены основные свойства β-лактамаз: субстратная специфичность, чувствительность к действию ингибиторов, особенности генетической детерминации. Особое внимание уделяется β-лактамазам грамотрицательных бактерий ТEM-, SHV-типа, их роли в формировании устойчивости к различным β-лактамам. Main structural and functional groups of bacterial β-lactamases are cited in the data review. Modern systems of classification, which was based on spectra of activity, sensitivity to inhibitors and peculiarities of molecular structure are described. The basic properties of β-lactamases are presented: substrate specificity, sensitivity to inhibitors, features of genetic determination. The special attention is given to β-lactamases of gram-negative bacteria TEM-, SHV-type and its role in the development of resistance to different β-lactams

Вплив іонів важких металів і цинкового комплексу на динаміку росту бактерій роду Pseudomonas

The problem of wastewater treatment is one of the most pressing issues from the beginning of the century. A special roleof the heavy metals in the pollution of the environment is due to their bioaccumulation, transfer through trophic chains, and high toxicity. Currently, advanced technologies for the wastewater treatment had been developed. Natural and cheap biological treatment methods of intensification of the natural processes of organic compounds decomposition by microorganisms under aerobic or anaerobic conditions are promising. Amongimportant processes are nitrification and denitrification. That’s why a great attention is paid to the microorganisms that are capable to realize these processes. The processes of interaction of the heavy metals ions and microorganisms are of great interest not only from the standpoint of basic science, but also as a possible use in biotechnological processes. Проблема очистки сточных вод – один из актуальных вопросов с начала века. Особое место тяжелых металлов среди загрязнителей окружающей среды связано с их накоплением в организме и передачей по трофическим цепям, их высокой токсичностью. Разработаны современные технологии очистки сточных вод: перспективы имеют естественные и дешевые биологические методы очистки, представляющие собой интенсификацию природных процессов разложения органических соединений микроорганизмами в аэробных или анаэробных условиях. Одни из основных – процессы нитрификации и денитрификации. Большое внимание уделяется микроорганизмам, способным выполнять эти процессы. Процессы взаимодействия между ионами тяжелых металлов и микроорганизмами представляют большой интерес не только для фундаментальной науки, а и как возможное применение в биотехнологических процессах. Проблема очищення стічних вод – одне з найактуальніших питань із початку століття. Особливе місце важких металів серед забруднювачів довкілля пов’язане з їх накопиченням в організмі та передачею трофічними ланцюгами, високою їх токсичністю. Розроблено сучасні технології очищення стічних вод: перспективи мають природні та найдешевші біологічні методи очищення, що являють собою інтенсифікацію природних процесів розкладання органічних сполук мікроорганізмами в аеробних або анаеробних умовах. Одні з основних – процеси нітрифікації та денітрифікації. Велика увага приділяється мікроорганізмам, здатним виконувати ці процеси. Процеси взаємодії між іонами важких металів і мікроорганізмами мають велике значення не тільки для фундаментальної науки, а і як можливе застосування у біотехнологічних процесах.

Strains of soil microorganisms promising for the creation of a complex plant protection product against mycoses and harmful insects

We evaluated the antagonistic activity of 23 strains of Bacillus spр. against phytopathogenic fungi Fusarium oxysporum, F. culmorum, F. moniliforme, Cladosporium herbarum, Alternaria alternata and Aspergillus niger. The antagonistic activity was tested by agar diffusion (the method of blocks). For determining the influence of bacteria on barley plants , ardent seeds were treated by cultural liquid (dilution 1 : 10) for 2 hours and germinated in Petri dishes on moist filter paper. The fungistatic effect of Bacillus sрp. separately and in combination with entomopathogens (in equal ratio) was determined by the level of inhibition of the fungi Fusarium spp. on a solid nutrient medium with 5% of the culture liquid. Insecticidal activity of microorganisms was determined in the model experiments by the percentage of death of the caterpillar Archips podana Scop. Strains of Bacillus sp. KMB-3 and Bacillus sp. KMB-6 inhibited the growth of all test cultures (zones of growth inhibition 11.4–30.6 and 11.5–29.4 mm, respectively). We established the absence of antagonism between selected strains and entomopathogenic bacteria Bacillus thuringiensis IMB-7186, fungi Beauveria bassiana IMB-F-100043. We found that treatment of barley seeds with culture liquids of Bacillus sp. KMB-3 and Bacillus sp. KMB-6 didn’t have a negative effect on the morphometric indices and dry weight of seedlings. We established that the highest percentage of growth inhibition of F. culmorum IMB-F-50716 was provided by a complex of Bacillus sp. KMB-3, B. bassiana IMB-F-100043 and B. thuringiensis IMB-7186, whose action was at the same level as the action of monoculture Bacillus sp. KMB-3 (85.4% and 84.7%, respectively). The highest percentage inhibition of growth of F. oxysporum ІМВ-F-54201 was provided by a complex of strains of Bacillus sp. KMB-3 and B. bassiana IMB-F-100043, whose effect was slightly inferior to that of the monoculture Bacillus sp. KMB-3 (68.4% and 75.1%, respectively). The insecticidal activity of complexes Bacillus sp. KMB-3, B. bassiana IMB-F-100043, B. thuringiensis IMB-7186 or Bacillus sp. KMB-6, B. bassiana IMB-F-100043, B. thuringiensis IMB-7186 insignificantly differed from that of the complex entomopathogens B. bassiana IMB-F-100043 and B. thuringiensis IMB-7186 (71.1%, 73.3% death versus 80.0%). The selected microbial complexes can be considered as promising for the development of a preparation for the protection of plants against fungal diseases and harmful insects

Phytochemical profiles and antimicrobial activity of the inflorescences of Sorbus domestica, S. aucuparia, and S. torminalis

The genus Sorbus L. is known for its extremely complex taxonomical relationships and health-promoting phytochemicals included in the composition of its floral constituents. The inflorescences of three Sorbus species (rowans), characterized by distinct molecular-genetic traits, were studied in order to examine the possible chemotaxonomic and antimicrobial value of their metabolites. GC–MS profiling of the hexane extracts of S. domestica, S. aucuparia, and S. torminalis inflorescences identified a total of 87 components, which represented six chemical classes (hydrocarbons, alcohols, esters, fatty acid, aldehydes, and ketones) and miscellaneous minor floral constituents (1-methylinosine, 5-amino tetrazole, 1,4-dimethylbenzene, 3,5-bis(1,1-dimethylethyl)-phenol, 3-acetoxy-7,8-epoxylanostan-11-ol, cycloeucalenol acetate, etc.). Principal component analysis (PCA) of the qualitative and quantitative heterogeneity of the floral metabolites determined 1-hentetracontanol, nonacosane, pentadecyl acrylate, 1-methylhexacosane, cycloeucalenol acetate, butyl acetate, and urs-12-ene as the main components which contributed to the differences between S. domestica, S. aucuparia and S. torminalis and resulted in the distinction between the rowan species. Disc-diffusion assays showed variability in activity of inflorescence extracts against Gram-negative (Enterobacter dissolvens, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae) and Gram-positive (Micrococcus lysodeikticus, Staphylococcus aureus, and S. epidermidis) bacterial and clinical fungal (Candida albicans) strains. The effect of S. torminalis was high against S. epidermidis and P. aeruginosa, while it was at its lowest against clinical C. albicans strains. Inflorescences of S. domestica showed the highest inhibition of P. aeruginosa, and moderate effects against S. epidermidis and C. albicans. Inflorescences of S. aucuparia caused low to moderate growth inhibition of both Gram-positive and Gram-negative bacterial strains, while it showed the highest effect on C. albicans. Antimicrobial properties of rowan inflorescences may be attributed to oleic, linoleic, arachidic, hexadecanoic, and pentadecanoic acids, 24-norursa-3,12-diene, hexahydrofarnesyl acetone, cycloeucalenol acetate, and other compounds which have known bioactivity. These findings indicated rowan inflorescences as a rich source of valuable secondary metabolites and allow us to assume an application of the floral constituents as chemotaxonomic markers of the genus Sorbus species

Микробиологические аспекты пробиотических препаратов

The main stages of the beginning and development of probiotic preparations, the general characteristics of modern probiotics, the scope of their use in medicine and veterinary are presented. The characteristics of microorganisms (bifidus bacteria, lactobacteria and Bacillus bacteria) used in the production of probiotics, the basic requirements that should be met by these organisms, as well as prospects for the development of probiotics are shown. Розглянуто основні етапи виникнення та розвитку пробіотичних препаратів, загальну характеристику сучасних пробіотиків, сфери їх використання в медицині та ветеринарії. Наведено характеристику мікроорганізмів (біфідобактерій, лактобактерій, бактерій роду Bacillus), які використовуються у виробництві пробіотиків, основні вимоги, яким повинні відповідати ці мікроорганізми, а також перспективи розвитку застосування пробіотиків.Рассмотрены основные этапы возникновения и развития пробиотических препаратов, общая характеристика современных пробиотиков, сферы их использования в медицине и ветеринарии. Дана характеристика микроорганизмов (бифидобактерий, лактобактерий, бактерий рода Bacillus), используемых в производстве пробиотиков, основные требования, которым должны отвечать эти микроорганизмы, а также перспективы развития применения пробиотиков.

Mechanical, Electrical and Magnetic Properties of Ferrogels with Embedded Iron Oxide Nanoparticles Obtained by Laser Target Evaporation: Focus on Multifunctional Biosensor Applications

Hydrogels are biomimetic materials widely used in the area of biomedical engineering and biosensing. Ferrogels (FG) are magnetic composites capable of functioning as magnetic field sensitive transformers and field assisted drug deliverers. FG can be prepared by incorporating magnetic nanoparticles (MNPs) into chemically crosslinked hydrogels. The properties of biomimetic ferrogels for multifunctional biosensor applications can be set up by synthesis. The properties of these biomimetic ferrogels can be thoroughly controlled in a physical experiment environment which is much less demanding than biotests. Two series of ferrogels (soft and dense) based on polyacrylamide (PAAm) with different chemical network densities were synthesized by free-radical polymerization in aqueous solution with N, N'-methylene-diacrylamide as a cross-linker and maghemite Fe2O3 MNPs fabricated by laser target evaporation as a filler. Their mechanical, electrical and magnetic properties were comparatively analyzed. We developed a giant magnetoimpedance (MI) sensor prototype with multilayered FeNi-based sensitive elements deposited onto glass or polymer substrates adapted for FG studies. The MI measurements in the initial state and in the presence of FG with different concentrations of MNPs at a frequency range of 1-300 MHz allowed a precise characterization of the stray fields of the MNPs present in the FG. We proposed an electrodynamic model to describe the MI in multilayered film with a FG layer based on the solution of linearized Maxwell equations for the electromagnetic fields coupled with the Landau-Lifshitz equation for the magnetization dynamics.This work was supported in part within the framework of the state task of the Ministry of Education and Science of Russia 3.6121.2017/8.9; RFBR grants 16-08-00609-a, 18-08-00178, and by the ACTIMAT ELKARTEK grant of the Basque Country Government. Selected studies were made at SGIKER Common Services of UPV-EHU and URFU Common Services. We thank I.V. Beketov, A.A. Chlenova, S.O. Volchkov, V.N. Lepalovskij, A.M. Murzakaev and A.A. Svalova for special support

Transformations of substituted cyanoiminooctahydroquinazolines under oxidation conditions

Substituted quinazolines of various degrees of saturation and functionalization possess a wide spectrum of biological activity, in particular, anticancer activity, which predetermines the importance of obtaining new representatives of this type of compounds and studying their practically useful properties. Methods for the preparation of 2-cyanoiminoquinazolines are poorly described in the literature, while their properties and oxidation reactions have not been studied at all. We have analyzed the stability of tautomeric forms of 2-cyanoiminoquinazolines, determined the activation energy of their formation using quantum-chemical calculations, studied their transformation under the action of strong oxidants (CrO3/AcOH, NaNO2/AcOH). Selective aromatization of the azoheterocycle and hydrolysis of the -CN-group to form 2-aminocarbamoylquinazoline occurred during oxidation. An increase in temperature from 120 to 160° C (using CrO3) resulted in the formation of 2-nitrosoquinazoline. The structure of our new obtained substances was established by spectral methods (IR, 1H, 13C NMR, HSQC, NOESY), a scheme of their formation has been proposed

Polyacrylamide Ferrogels with Magnetite or Strontium Hexaferrite: Next Step in the Development of Soft Biomimetic Matter for Biosensor Applications

Magnetic biosensors are an important part of biomedical applications of magnetic materials. As the living tissue is basically a " soft matter." this study addresses the development of ferrogels (FG) with micron sized magnetic particles of magnetite and strontium hexaferrite mimicking the living tissue. The basic composition of the FG comprised the polymeric network of polyacrylamide, synthesized by free radical polymerization of monomeric acrylamide (AAm) in water solution at three levels of concentration (1.1 M, 0.85 M and 0.58 M) to provide the FG with varying elasticity. To improve FG biocompatibility and to prevent the precipitation of the particles, polysaccharide thickeners-guar gum or xanthan gum were used. The content of magnetic particles in FG varied up to 5.2 wt % depending on the FG composition. The mechanical properties of FG and their deformation in a uniform magnetic field were comparatively analyzed. FG filled with strontium hexaferrite particles have larger Young's modulus value than FG filled with magnetite particles, most likely due to the specific features of the adhesion of the network's polymeric subchains on the surface of the particles. FG networks with xanthan are stronger and have higher modulus than the FG with guar. FG based on magnetite, contract in a magnetic field 0.42 T, whereas some FG based on strontium hexaferrite swell. Weak FG with the lowest concentration of AAm shows a much stronger response to a field, as the concentration of AAm governs the Young's modulus of ferrogel. A small magnetic field magnetoimpedance sensor prototype with Co68.6Fe3.9Mo3.0Si12.0B12.5 rapidly quenched amorphous ribbon based element was designed aiming to develop a sensor working with a disposable stripe sensitive element. The proposed protocol allowed measurements of the concentration dependence of magnetic particles in gels using magnetoimpedance responses in the presence of magnetite and strontium hexaferrite ferrogels with xanthan. We have discussed the importance of magnetic history for the detection process and demonstrated the importance of remnant magnetization in the case of the gels with large magnetic particles.This work was supported in part within the framework of the state task of the Ministry of Education and Science of Russia 3.6121.2017/8.9; RFBR grant 16-08-00609 and by the ACTIMAT grant of the Basque Country Government. Selected studies were made at SGIKER Common Services of UPV-EHU and URFU Common Services. We thank I.V. Beketov, A.A. Svalova, Burgoa Beitia, A. Amirabadizadeh, A. Garcia-Arribas and I. Orue for their special support

Anaerobic microbial associations degrading aminoaromatic acids

Anaerobic microbial associations have been isolated that degrade aminoaromatic acids to methane and carbon dioxide at high rates. Significant differences between the morphological, cytological, and physiological traits of cultures isolated from samples of adapted and unadapted sludge are shown. The effects of cultivation temperature, illumination, and presence of mineral nitrogen and bicarbonate in the medium upon adaptation of enrichment cultures to substrates and subsequent behavior of the anaerobic associations have been studied. Intermediate and final products of degradation of aminoaromatic compounds and the sequence of their formation in the cultures have been determined. We have also studied the effects of exogenous electron acceptors and additional carbon sources on the degradation of aminoaromatic compounds