Doctor of Philosophy

dissertationExperimental models that faithfully reflect both normal physiological and pathological conditions represent an essential cornerstone of both the basic and applied sciences. However, the degrees to which these models represent actual in vivo conditions and environments greatly affect their ability to accurately produce clinically relevant responses to stimuli such as drug exposures. This dissertation introduces an in vitro kidney proximal tubule model that aims to retain tissue architecture, cell organization, cell-matrix and cell-cell interactions, and physiological cellular responses in long-term culture, and assess its ability to preserve differentially and functionally stable primary cells during exposure to drugs known to be nephrotoxic. These features are achieved by encapsulating suspended harvested viable proximal tubule fragments containing their epithelial cells in a three-dimensional hyaluronic acid (HA) hydrogel matrix. Proximal tubule fragment (i.e., "organoid") encapsulation, and not their isolated cells suspensions, in the hydrogel endows the model with the capability to retain native cellular organization, extracellular matrix, and intra- and extra-cellular interactions, while limiting non-native cell-polymer interfaces. Data collected for these cultures indicate that proximal tubule epithelial cells sustain cellular gluconeogenic potential, differential markers, and functional ligands. Moreover, these kidney cells in vitro were capable of responding to exogenous agents (i.e., drug introductions) with induction of in vivo-relevant gene and protein biomarkers as well as accurate cytokine, cytochrome, and iv metabolite expression patterns. The utility of the model for assessing potential nephrotoxic agents was further validated by comparison to the "gold standard" of current in vitro toxicology: immortalized cell monolayers grown on plastic. Results demonstrate significant improvements in cell phenotypic fidelity for 3D organoid cultures over cells supported via standard in vitro culture techniques that produce most clinically measured biomarkers. The obtained results indicate that preservation of the cellular microenvironment is key to not only sustaining functional proximal tubule cells in vitro but also in preserving their natural responses to the same nephrotoxic indicators as expressed in animal toxicity models. The proposed 3D in vitro culture model bridges the gap between overly simplistic cellular and costly in vivo assessment, and opens possibilities for direct, reliable and predictive comparisons between in vitro and clinical data

Gas Chromatographic Investigation of Oil Biodegradation Degree

The research of the degree of oil biodegradation by gas chromatography and individual classes of hydrocarbons by various strains of hydrocarbon-oxidizing microorganisms isolated from indigenous microflora of oil fields was carried out. It has been shown that some of the investigated strains of hydrocarbon-oxidizing microorganisms are 100% capable to biotransform naphthenes and olefins, showing high activity in the destruction of paraffins and isoparaffins. There are no signs of biodegradation of aromatic compounds due to the large duration of the process. All investigated strains of hydrocarbon-oxidizing microorganisms are largely able to reduce the total number of individual components of oil. The obtained data can be used to develop new biologics of the purpose

Microbiological Quality Control of Probiotic Products

Microbiological quality control of probiotic products such as Imunele, Dannon, Pomogayka showed that they contain living cultures of the Lactobacillus Bifidobacterium genus in the amount of 107 CFU/ml, which corresponds to the number indicated on the label of products. It is identified that the survival rate of test-strains cultured with pasteurized products does not exceed 10%. The cell concentration of target-microorganisms was reduced by 20-45% after the interaction with living probiotic bacteria. Thus, the yogurt Activia has the most antagonistic activity

Study of the Hydrocarbon-oxidizing Activity of Bacteria of the Genera Pseudomonas and Rhodococcus

AbstractThe selective activity of hydrocarbon-oxidizing microorganisms with regard to the degradation of alkanes, cycloalkanes, arenes was presented. The hydrocarbon-oxidizing activity of microorganisms of the genera Rhodococcus and Pseudomonas such as heptane, cyclohexane, toluene within the hydrocarbons destruction was determined. The growth rate for various hydrocarbons differs. Thus, the average specific growth rate of hydrocarbon-oxidizing microorganism (HOM) of the genus Rhodococcus is twice more than these substrates

Study of the Hydrocarbon-oxidizing Activity of Bacteria of the Genera Pseudomonas and Rhodococcus

The selective activity of hydrocarbon-oxidizing microorganisms with regard to the degradation of alkanes, cycloalkanes, arenes was presented. The hydrocarbon-oxidizing activity of microorganisms of the genera Rhodococcus and Pseudomonas such as heptane, cyclohexane, toluene within the hydrocarbons destruction was determined. The growth rate for various hydrocarbons differs. Thus, the average specific growth rate of hydrocarbon-oxidizing microorganism (HOM) of the genus Rhodococcus is twice more than these substrates

Study of application of hydrophobic fibrous sorbents for water purification from metal ions

Sorption properties of hydrophobic fibrous sorbents on the basis of polypropylene and polyethylene terephthalate produced from thermoplastic polymer wastes to metal ion series in aqueous media has been studied. Based on the experimental data of extraction degree dependencies on fibre laying density, dispersity, presence of air in sorbent, volume of pass solution the mechanism of metal ion sorption from aqueous media with hydrophobic fibrous materials is suggested

A novel reagentless glutamate microband biosensor for real-time cell toxicity monitoring

A reagentless glutamate biosensor was applied to the determination of glutamate released from liver hepatocellular carcinoma cells (HepG2) in response to toxic challenge from various concentrations of paracetamol. A screen printed carbon electrode (SPCE) containing the electrocatalyst Meldola's Blue (MB-SPCE) served as the electron mediator for the oxidation of NADH.A mixture of the enzyme glutamate dehydrogenase (GLDH), cofactor nicotinamide adenine dinucleotide (NAD+) and the biopolymer chitosan (CHIT) were drop-coated onto the surface of the transducer (MB-SPCE) in a simple one step fabrication process.The reagentless biosensor was used with amperometry in stirred solution at an applied potential of +0.1 V (vs. Ag/AgCl). All experiments were carried out at the following conditions: pH 7, temperature 37 °C, atmosphere 5% CO2.The linear range of the device was found to be 25–125 μM in phosphate buffer (75 mM, containing 0.05 M NaCl) and 25–150 μM in cell culture medium. The limits of detection (LOD) were found to be 1.2 μM and 4.2 μM based on three times signal to noise, using PBS and culture medium respectively. The sensitivity was calculated to be 106 nA μM−1 cm−2 and 210 nA μM−1 cm−2 in PBS and cell medium respectively. The response time was ∼60 s in an agitated solution.HepG2 cells were exposed to various concentrations of paracetamol (1 mM, 5 mM and 10 mM) in order to investigate the drug-induced release of glutamate into the culture medium in real time. Two toxicity studies were investigated using different methods of exposure and analysis.The first method consisted of a single measurement of the glutamate concentration, using the method of standard addition, after 24 h incubation. The concentrations of glutamate were found to be 52 μM, 93 μM and 177 μM, released on exposure to 1 mM, 5 mM and 10 mM paracetamol respectively.The second method involved the continuous monitoring of glutamate released from HepG2 cells upon exposure to paracetamol over 8 h. The concentrations of glutamate released in the presence of 1 mM, 5 mM and 10 mM paracetamol, increased in proportion to the drug concentration, ie: 16 μM, 28 μM and 62 μM respectively. This result demonstrates the feasibility of using this approach to monitor early metabolic changes after exposure to a model toxic compound

ИНТЕЛЛЕКТУАЛЬНАЯ СИСТЕМА ДЛЯ СТРАТЕГИЧЕСКИХ РЕШЕНИЙ

The authors assume that today’s theory and practice bring tools of managerial decision-making in line with group methods. The article gives a description of the developed intelligent system to support strategic decision-making processes under conditions of uncertainty and risk. Its mathematical core is shown using a variety of methods of analysis, as well as of assessment of preferences on the basis of multicriteria choice and of given set of alternative decisions. The system can be used to solve a wide range of tasks in the field of analytical forecasting and planning of transport infrastructure development.Авторы исходят из того, что инструменты подготовки управленческих решений приводятся сегодня теорией и практикой в соответствие с групповыми методами. В статье дается описание разработанной интеллектуальной системы для поддержки процедур принятия стратегических решений в условиях неопределенности и риска. Показано математическое ее ядро с использованием различных методов анализа, оцени отношений предпочтения на основе многокритериального выбора и заданного набора альтернатив. Система может быть применена для решения широкого спектра задач в области аналитического прогнозирования и планирования развития объектов транспортной инфраструктуры

Opportunities for organoids as new models of aging.

The biology of aging is challenging to study, particularly in humans. As a result, model organisms are used to approximate the physiological context of aging in humans. However, the best model organisms remain expensive and time-consuming to use. More importantly, they may not reflect directly on the process of aging in people. Human cell culture provides an alternative, but many functional signs of aging occur at the level of tissues rather than cells and are therefore not readily apparent in traditional cell culture models. Organoids have the potential to effectively balance between the strengths and weaknesses of traditional models of aging. They have sufficient complexity to capture relevant signs of aging at the molecular, cellular, and tissue levels, while presenting an experimentally tractable alternative to animal studies. Organoid systems have been developed to model many human tissues and diseases. Here we provide a perspective on the potential for organoids to serve as models for aging and describe how current organoid techniques could be applied to aging research