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Search Results: 1 - 10 of 2300 matches for " Irina Bakunina "
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Comparative Analysis of Glycoside Hydrolases Activities from Phylogenetically Diverse Marine Bacteria of the Genus Arenibacter
Irina Bakunina,Olga Nedashkovskaya,Larissa Balabanova,Tatyana Zvyagintseva,Valery Rasskasov,Valery Mikhailov
Marine Drugs , 2013, DOI: 10.3390/md11061977
Abstract: A total of 16 marine strains belonging to the genus Arenibacter, recovered from diverse microbial communities associated with various marine habitats and collected from different locations, were evaluated in degradation of natural polysaccharides and chromogenic glycosides. Most strains were affiliated with five recognized species, and some presented three new species within the genus Arenibacter. No strains contained enzymes depolymerizing polysaccharides, but synthesized a wide spectrum of glycosidases. Highly active β- N-acetylglucosaminidases and α- N-acetylgalactosaminidases were the main glycosidases for all Arenibacter. The genes, encoding two new members of glycoside hydrolyses (GH) families, 20 and 109, were isolated and characterized from the genomes of Arenibacter latericius. Molecular genetic analysis using glycosidase-specific primers shows the absence of GH27 and GH36 genes. A sequence comparison with functionally-characterized GH20 and GH109 enzymes shows that both sequences are closest to the enzymes of chitinolytic bacteria Vibrio furnissii and Cellulomonas fimi of marine and terrestrial origin, as well as human pathogen Elisabethkingia meningoseptica and simbionts Akkermansia muciniphila, gut and non-gut Bacteroides, respectively. These results revealed that the genus Arenibacter is a highly taxonomic diverse group of microorganisms, which can participate in degradation of natural polymers in marine environments depending on their niche and habitat adaptations. They are new prospective candidates for biotechnological applications due to their production of unique glycosidases.
Stereochemical course of hydrolytic reaction catalyzed by alpha-galactosidase from cold adaptable marine bacterium of genus Pseudoalteromonas
Irina Y. Bakunina,Larissa A. Balabanova,Vasiliy A. Golotin,Valeriy A. Rasskazov
Frontiers in Chemistry , 2014, DOI: 10.3389/fchem.2014.00089
Abstract: The recombinant α-galactosidase of the marine bacterium (α-PsGal) was synthesized with the use of the plasmid 40Gal, consisting of plasmid pET-40b (+) (Novagen) and the gene corresponding to the open reading frame of the mature α-galactosidase of marine bacterium Pseudoalteromonas sp. KMM 701, transformed into the Escherichia coli Rosetta(DE3) cells. In order to understand the mechanism of action, the stereochemistry of hydrolysis of 4-nitrophenyl α-D-galactopyranoside (4-NPGP) by α-PsGal was measured by 1H NMR spectroscopy. The kinetics of formation of α- and β-anomer of galactose showed that α-anomer initially formed and accumulated, and then an appreciable amount of β-anomer appeared as a result of mutarotation. The data clearly show that the enzymatic hydrolysis of 4-NPGP proceeds with the retention of anomeric configuration, probably, due to a double displacement mechanism of reaction.
Application of prodigiosin as a colorant for polyolefines  [PDF]
Irina Ryazantseva, Irina Andreyeva
Advances in Biological Chemistry (ABC) , 2014, DOI: 10.4236/abc.2014.41004
Abstract: Serratia marcescens strain 9986 is a producer of prodigiosin used as a dye of polyolefines (polyethylene, ultratene). The biosynthesis of pigment was closely connected with controlled growth parameters. A prodigiosin yield 0.2 - 0.4 mg per l of culture medium in the batch culture under aerobic conditions was obtained. Prodigiosin was extracted from crude biomass treated by 0.1% of sodium dodecyl sulfate (SDS). This novel elaborated stage is necessary for thermostability a dye in polymer. The consumption of prodigiosin preparation is more economical in the technology of the coloration of polyolefines. The elaborated method has been manufactured for dyeing polyethylene by biological pigment-articles of the common use corresponding to the technological standard.
The Main Difficulties When Studying Russian Verbs of Motion in a Figurative Meaning  [PDF]
Irina Skripnikova
Open Journal of Modern Linguistics (OJML) , 2012, DOI: 10.4236/ojml.2012.24019
Abstract: Russian language acquisition requires deep and intensive studying of the concept of verbs of motion. There is a strong opinion that verbs of motion are one of the hardest concepts in the Russian language. However, it is an important issue, as motion verbs are among the most used in any language and nowadays there are hundreds of expressions with these verbs which can be heard quite frequently in the Russian language. Needless to say that mastering these verbs is even harder when they have figurative meaning. Therefore, the purpose of this paper is to demonstrate the importance of studying the figurative meanings of Russian verbs of motion and to prove that the process of teaching students these verbs is more efficient when they are compared with their English equivalents.
Preventative Strategies in the Management of ROP: A Review of Literature  [PDF]
Irina Livshitz
Open Journal of Pediatrics (OJPed) , 2015, DOI: 10.4236/ojped.2015.52018
Abstract:

Retinopathy of prematurity (ROP) is a potentially blinding eye disorder that primarily affects premature infants weighing 1250 grams or less that are born before 31 weeks of gestation. It is one of the most common causes of visual loss in childhood and can lead to lifelong vision impairment and blindness. Certain strategies for prevention have been confirmed by numerous trials, namely the role of oxygen therapy as an independent risk factor for the development of ROP and the benefits of strict control of premature infant oxygen saturations in the NICU. There is valuable data that supports use of other approaches, such as beta adrenergic blockade and IGF-1 supplementation, for which clinical trials are still in the works to establish clear protocols for their clinical use. Supplementation with vitamin A, omega-3 fatty acids, and inositol are all exciting arenas for further trials as preliminary data shows promising results in ROP prevention. It has also been shown that the benefit of vitamin E is not worth the increased incidence of NEC and sepsis as potential side effects. Furthermore, while it was an interesting idea to use the chelator D-penicillamine as a preventative strategy for ROP, the results of multiple trials seemed to be equivocal. This brief review is not all-inclusive, as there are many more modes of prevention currently being studied.

Principles of the analysis of structure of chaffinch song (Fringilla coelebs L.). Individual variability of song  [PDF]
Olesya Astakhova, Irina Byome
Open Journal of Animal Sciences (OJAS) , 2012, DOI: 10.4236/ojas.2012.23026
Abstract: Song of birds is subtle and flexible species specific feature, like as the morphology signs. Species specific song of chaffinch (Fringilla coelebs L.) can be judged as precise character in the image on sonograms. The song has the certain structure and shares (divides) on the parts, elements, which consists of them. Individual variability of songs of one type will consist in unique singing each of chaffinch males, who form a local population.
Induction Heating in the Processing of Ti & Zr  [PDF]
Victor Demidovich, Irina Rastvorova
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2014, DOI: 10.4236/jemaa.2014.613042
Abstract: Induction heating has important applications in science and industry. The method of induction heating can be successfully used for melting and heat treatment of titanium and zirconium alloys. Different applications using induction precise heating before plastic deformation are discussed in this paper. For alloys of many metals such as titanium, zirconium, niobium, tantalum, etc., it is important to provide precision heating with a high degree of homogeneity of the temperature field and strict adherence to the condition of heating. This is explained by polymorphism of the alloys based on these metals, their chemical activity at high temperatures and the specific thermal and electrical properties. It is very important for induction heating to define the extreme achievable unevenness of the temperature field. For special alloys it is necessary to use resistance furnaces for homogenization of billets’ temperature after heating in the inductors. Optimal control can be used for massive billets to reduce significantly the heating time, energy expenses and to improve the quality of the temperature field distribution. Optimization of induction heating process can be achieved by synchronous solution of the problem of optimal control and design with specially developed models.
Risk Modelling of Organic Pollution in Lake Sediments  [PDF]
Irina Schneider, Yana Topalova
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.75053
Abstract:

A risk situation of organic pollutants accumulation in the sediments of the dams from Cascade “Middle Iskar” (NW Bulgaria) is simulated in the present study. The aim is risk modelling of organic pollution in lake sediments and on base of the investigated key chemical and enzymological parameters to risk assessment. A model process in lab scale with addition of whey as a source of organic pollutants was simulated. Two situations near to real conditions were studied: 1) at a decreased concentration of organic pollutants (chemical oxygen demand was 0.265 gO2.kg-1) in the case of discharge of sediments downstream of the river (control situation); 2) at an accumulation of organic pollutants (chemical oxygen demand was 1.463 gO2.kg-1) in the sediments (risk event). The dynamics of chemical oxygen demand (COD), concentration of proteins and lactose as well as of the key enzymological indicators (phosphatase activity index—PAI, anaerobic dehydrogenase activity, protease and ?-galactosidase activities) were investigated. The data from Risk Assessment showed that there is a hazard from higher protein concentration at the end of the process in comparison with the control situation. The risk about COD and lactose concentration during the risk modelling was acceptable. The obtained results showed that the PAI can be used as an indicator for early warning of the organic pollution with protein nature.

The Exact and Approximate Solutions of Some Boundary Value Problems in Domains with Angular Points of the Boundary  [PDF]
Irina Menshova, Mikhail Kovalenko
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.51006
Abstract:
On the basis of the exact solution of biharmonic problems of elasticity theory in a half-strip one possible reason is shown of those problems that arise when an approximate or numerical approaches leading the solution of boundary value problems to infinite systems of linear algebraic equations. Construction of exact solutions of some boundary value problems for differential equations in partial derivatives is not possible without their extensions to Riemann surfaces. Moreover, each of the boundary value problem corresponds to its Riemann surface. This fact is important to consider when developing an effective approximate and numerical methods of solving boundary value problems.
The lability of behavior as a marker of comorbid depression and anxiety  [PDF]
Irina N. Trofimova, William Sulis
Advances in Bioscience and Biotechnology (ABB) , 2010, DOI: 10.4236/abb.2010.13027
Abstract: This study examines nine dynamical and three emotional aspects of behavior in depression and anxiety, singly and comorbidly. The study employs the Structure of Temperament Questionnaire Compact (STQ 77), whose 12 scales assess the energetic, lability and sensitivity aspects of behavior in the physical, social, mental and emotional domains. The STQ 77 was administered to 86 patients with Major Depression, 85 patients with an anxiety disorder, 43 patients with comorbid depression and anxiety, and 71 subjects without depression or anxiety disorder all presenting to a private outpatient clinical practice. Results: 1) Depression was associated with self-reports of increased impulsivity and rigidity of behavior; 2) Depressed patients reported significantly lower physical energy, tempo of physical activity and plasticity of behavior. The presence of comorbid anxiety further worsened these effects; 3) The ability to sustain attention on a mental task and to learn new information was lower in depressed patients than in other groups. Conclusions: comorbid depression and anxiety might be associates, decreasing adaptivity and the self-regulatory balance of behavior, leading to the de- velopment of extremes in behavioral reactivity (impulsivity and rigidity).v
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