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Raczynska E.D.,Warsaw University of Life Sciences | Sapula M.,SGGW
Journal of Molecular Modeling | Year: 2016

Consequences of ionization were studied by quantum-chemical methods (DFT and PCM) for 1-methylcytosine (MC)—a model of the nucleobase cytosine (C) connected with sugar in DNA. For calculations, three prototropic tautomers (one amino and two imino forms) and two imino zwitterions were considered, including conformational or configurational isomerism of exo heterogroups. Ionization and interactions between neighboring groups affect intramolecular proton-transfers, geometric and thermodynamic parameters, and electron delocalization for individual isomers. We discovered that an imino isomer is present in the isomeric mixture in the highest amount for positively ionized MC. Its contribution in neutral and negatively ionized MC is considerably smaller. Acid-base parameters for selected radical ions were estimated in the gas phase and compared to those of neutral MC. Gas-phase acidity of radical cations is close to that of the conjugate acid of MC, and gas-phase basicity of radical anions is close to that of the conjugate base of MC. Various routes of amino-imino conversion between neutral and ionized isomers were considered. Energetic-barrier for intramolecular proton-transfer in MC is close to that in the parent system—formamidine. © 2016, The Author(s).


PubMed | SGGW and Warsaw University of Life Sciences
Type: Journal Article | Journal: Journal of molecular modeling | Year: 2016

Consequences of ionization were studied by quantum-chemical methods (DFT and PCM) for 1-methylcytosine (MC)-a model of the nucleobase cytosine (C) connected with sugar in DNA. For calculations, three prototropic tautomers (one amino and two imino forms) and two imino zwitterions were considered, including conformational or configurational isomerism of exo heterogroups. Ionization and interactions between neighboring groups affect intramolecular proton-transfers, geometric and thermodynamic parameters, and electron delocalization for individual isomers. We discovered that an imino isomer is present in the isomeric mixture in the highest amount for positively ionized MC. Its contribution in neutral and negatively ionized MC is considerably smaller. Acid-base parameters for selected radical ions were estimated in the gas phase and compared to those of neutral MC. Gas-phase acidity of radical cations is close to that of the conjugate acid of MC, and gas-phase basicity of radical anions is close to that of the conjugate base of MC. Various routes of amino-imino conversion between neutral and ionized isomers were considered. Energetic-barrier for intramolecular proton-transfer in MC is close to that in the parent system-formamidine.


Kapturowska A.,SGGW | Stolarzewicz I.,SGGW | Chmielewska I.,Miedzywydzialowe Studium Biotechnologii | Bialecka-Florjanczyk E.,SGGW
Zywnosc. Nauka. Technologia. Jakosc/Food. Science Technology. Quality | Year: 2011

Sonication technique has been commonly used in food industry, first of all in food preservation and food processing. The objective of this study was to assess the sonication as an alternative method to inactivate yeast cells. Additionally, it was considered whether or not the sonication could be used to obtain intracellular protein solution. Cells of Saccharomyces cerevisiae 2200 strain and a raw yeast biomass were sonicated in a 20 kHz horn-type sonicator. It was found that the time, duty cycle, and power of ultrasounds significantly impacted the cell inactivation and the protein extraction degree. The efficiency of extracting proteins from the cultured S. cerevisiae 2200 yeast strain amounted to 60 %, and from the raw baker's yeast to 43 %. The disruption of yeast cells by ultrasounds can be a good laboratory technique used to permeabilize cell wall and to extract intracellular proteins. After sonication, the count of live yeast cells decreased by 100 to 1000 times compared to their initial count expressed as cfu/cm 3; this effect can be intensified by combing the activity of ultrasounds with a thermal factor.


Grabiec K.,SGGW | Burchert M.,SGGW | Milewska M.,SGGW | Blaszczyk M.,SGGW | Grzelkowska-Kowalczyk K.,SGGW
Postepy Higieny i Medycyny Doswiadczalnej | Year: 2013

Cachexia is a multifactorial syndrome of atrophy of skeletal muscle and adipose tissue, resulting in progressive loss of body weight associated with low quality of life and poor prognosis in cancer. Studies on experimental animal models and observations on patients have shown that the soluble factors secreted by tumor cells and tissues of the patient can participate in regulation of the wasting process. Cachexia is often accompanied by anorexia, which is caused by predominance of signals inhibiting appetite in the hypothalamus, such as release of proopiomelanocortin and anorexigenic action of proinflammatory cytokines (IL-1α, IL-1β, IL-6, TNF-α). Cachexia is also accompanied by extensive metabolic changes consisting of increase of resting energy expenditure and disturbance of carbohydrate, protein and lipid metabolism. Increased expression of protein uncoupling phosphorylation leads to increased thermogenesis in skeletal muscle. Tumor tissue hypoxia caused by its growth beyond blood vessels activates the transcription factor HIF-1, which results in increase in glycolysis, and leads to lactic acid accumulation and activation of the energy inefficient Cori cycle. Loss of fat tissue is caused by increase of lipolysis induced by lipid-mobilizing factor (LMF) and proinflammatory cytokines. Skeletal muscle wasting in cachexia is caused by a reduction of protein synthesis at the stage of initiation and elongation of translation and the simultaneous increase of protein degradation via ubiquitin-dependent and lysosomal pathways. The main mediators of skeletal muscle wasting in cancer are proteolysis-inducing factor (PIF), proinflammatory cytokines, and angiotensin II acting through increased levels of reactive oxygen species (ROS) and nuclear factor NF-κB activation, as well as glucocorticoid activated FOXO transcription factors and myostatin. Understanding of the complexity of the interaction of factors produced by the tumor and the patient>s body may form the basis for the development of effective treatments for cachexia in cancer and other pathological conditions.


Piotrowska E.,SGGW | Bodurkiewicz L.,SGGW
Przeglad Elektrotechniczny | Year: 2010

The investigations of resistance heating of different elements made of copper and kanthal has been carried out. The mathematical model of heating making use of thermo-electric analogy has been built. Next some parameters verifying the model fitting has been estimated.


Jezewska-Zychowicz M.,SGGW
Zywnosc. Nauka. Technologia. Jakosc/Food. Science Technology. Quality | Year: 2014

In the paper, the impact was discussed of various factors on the acceptance of innovative food product. It was proved that many factors decided on the acceptance of innovations; they could be classified into three categories: characteristics of social system; characteristics of the innovation itself; and characteristics of consumer, the addressee of the innovation. Social system is represented by a social, economic, and political environment; and, in the research studies, a social trust issue is most frequently pointed out as is its impact on choosing food and utilizing informative media. Of the food characteristics referred to in the research studies on consumer acceptance of innovative food product, among other things, the following are included: price, comfort in use, taste, overall appearance, and other specific characteristics that depend on the type of food. The profile of consumers includes their psychological, socio-demographic, and psycho- social features. © Polskie Towarzystwo Technologów Żywności, Kraków 2014.


The elements modelling heat transfer in the heat exchanger were investigated. The method of parametric identification revealed the oscillations in the STEP responses of these elements. The four-terminal network diagram corresponding to the modelling exchanger was prepared using a method of the equivalent thermal network (ETN) based on the electro-thermal analogy. The oscillations in the STEP responses indicate that ETN diagram of the heat exchanger should include a thermal inductivity element. The thermal inductivity idea correspond to potential and kinetic energy exchange during the heat exchange process which induces the oscillations.


Raczynska E.D.,Warsaw University of Life Sciences | Kolczynska K.,SGGW | Stepniewski T.M.,SGGW | Kaminska B.,Warsaw University of Life Sciences
Computational and Theoretical Chemistry | Year: 2013

Electron delocalization, which plays a principal role for the tautomeric adenine system, was studied for all possible major, minor, and rare tautomers of neutral, oxidized, and reduced adenine. The recently extended geometry-based HOMED (harmonic oscillator model of electron delocalization) index, which measures any type of resonance conjugation (π-π, n-π, and σ-π), was applied to the geometries of adenine isomers optimized at the DFT(B3LYP)/6-311+G(d,p) level. For neutral adenine, variations of the HOMED indices estimated for the whole tautomeric systems (eleven bonds) are almost parallel to those of the relative Gibbs energies (δ. G), which measure the thermodynamic stabilities of individual isomers. Some subtle effects, being a consequence of intramolecular interactions of neighboring groups and variability of electron delocalization for the imidazole and pyrimidine fragments, perturb this relation. One-electron oxidation has slight effect on the general HOMED/δ. G relation. The favored canonical NH. NH tautomer is well delocalized for both neutral and oxidized adenine. One-electron reduction dramatically changes electron delocalization and thermodynamic stability of individual tautomers that two subfamilies can be distinguished on the HOMED vs δ. G plot, one for the NH. NH tautomers and the other one for the NH. CH isomers. The reduced canonical NH. NH tautomer (although well delocalized) is not the favored one. The non-aromatic NH. CH tautomer predominates in the tautomeric mixture, indicating that aromaticity is not the main factor that dictates the tautomeric preference for reduced adenine. © 2013 Elsevier B.V.


Raczynska E.D.,Warsaw University of Life Sciences | Kolczynska K.,SGGW | Stepniewski T.M.,SGGW
Journal of Molecular Modeling | Year: 2012

The consequences of one-electron oxidation and one-electron reduction were studied for 4-aminopyrimidine (4APM), which displays prototropic tautomerism. Since experimental techniques are incapable of detecting less than 0.1% of minor tautomers, quantum-chemical calculations [DFT(B3LYP)/6-311+G(d,p)] were carried out for all possible tautomers of neutral 4AMP and its redox forms, 4APM +• and 4APM-•. Four tautomers were considered: one amine and three imine tautomers (two NH and one CH form). Geometric isomerism of the exo=NH group was also taken into account. One-electron oxidation (4APM - e → 4APM+•) has no significant effect on the tautomeric preferences; it influences solely the composition of the tautomeric mixture. The amine tautomer is favored for both 4APM +• and 4APM. An interesting change in the tautomeric preference occurs for 4APM-•. One-electron reduction (4APM+e → 4APM-•) favors the C5 atom for the labile proton. The preference of the imine CH tautomer in the tautomeric mixture of 4APM-• may partially explain the origin of CH tautomers in nucleobases. © Springer-Verlag 2012.


Obiedzinska A.,SGGW | Waszkiewicz-Robak B.,SGGW
Zywnosc. Nauka. Technologia. Jakosc/Food. Science Technology. Quality | Year: 2012

During the increased demand for "natural" food in the group of vegetable fats, consumers search for products other than those produced by extracting oils from seeds with the use of organic solvents or those undergoing subsequent chemical and physical refining processes. Cold pressed oils are such products, and when eaten, they can prevent or retard the development of diet-related lifestyle diseases such as obesity, coronary heart disease, and hypertension. Among the cold pressed oils, there are oils obtained from seeds (flax, camelina, evening primrose, borage, amaranthus, pumpkin, black currant), fruits (olives, sea buckthorn), nuts (hazelnuts, walnuts), or germs (wheat kernel). First of all, they are a rich source of unsaturated fatty acids, including essential fatty acids: linoleic and alpha-linolenic. Also, they provide bioactive compounds such as tocopherols and tocotrienols, free and esterified sterols, hydrocarbons (squalene), triterpenic alcohols, carotenoids, chlorophylls, and other compounds responsible for the colour, which are very valuable for human nutrition. The content level of those compounds in cold pressed oils mainly depends on the quality, the type, and the variety of raw substances. The additives applied did not inhibit the production of primary lipid oxidation products (peroxides and hydroperoxides), and the thyme extract demonstrated a strong oxidation-supporting activity. An antioxidant activity of all the additives was observed with regard to the secondary lipid oxidation products denoted as TBARS. None of the additives showed any protective activity are regards the egzogenitc amino acids. The highest loss of the available lysine was found in a sample with rosemary extract added; it amounted to nearly 51 %. The highest decrease in the content of available methionine, amounting to about 41 %, was reported in the samples with the thyme extract applied. The protective activity of anti-oxidants was found as regards the thiamine. In the samples with BHT and rosemary additives, significantly lower losses of this vitamin were found compared to the control sample.

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