Chlorpromazine effect on lysozyme-lipid interactions

Despite considerable research efforts, the molecular mechanisms of anaesthetic action still remain the matter of extensive debates. According to one viewpoint, anaesthetics alter the properties of lipid bilayer which, in turn, affects the functions of embedded membrane proteins. In contrast, protein-based theories of anaesthetic action postulate that the drugs modulate the functions of membrane proteins through direct association. To develop a unique conception of anaesthesia further in-depth investigations of drug-membrane interactions are strongly required. In the present work a well-known fluorescent probe pyrene has been employed to gain molecular insights into the interactions between amphipathic phenothiazine derivative chlorpromazine (CPZ) and model membranes composed of cationic globular protein lysozyme (Lz), and lipid vesicles prepared from zwitterionic lipid phosphatidylcholine (PC) and its mixtures with anionic lipid cardiolipin (CL) in the molar ratios 19:1, 9:1 and 4:1. To give unambiguous interpretation of the drug effect on protein-lipid interactions, we first analyzed the changes in pyrene excimerization due to the formation of either CPZ-lipid or Lz-lipid complexes. Pyrene excimer-to-monomer intensity ratio (E/M), a parameter which reflects the alterations in membrane free volume, was found to decrease upon Lz or CPZ binding to the lipid vesicles. Apparently, embedment of the protein and drug molecules into the hydrophobic region of lipid bilayer gives rise to the increase in lipid packing, decrease in the rate of trans-gauche isomerization of the lipid acyl chains and, consequently, reduction of membrane free volume. At the next step of the study, we analysed the changes in the rate of pyrene excimerization upon Lz addition to drug-lipid mixtures. In CL-containing liposomes the presence of CPZ does not modify the magnitude and sign of protein effect on membrane free volume. This implies that CPZ is incapable of perturbing Lz structure and exerted no influence on the protein interactions with this kind of liposomes. In contrast, in PC vesicles E/M ratio appeared to increase upon lysozyme binding to CPZ-modified model membranes. This finding may be explained in terms of two possibilities: (i) CPZ induces the formation of the new Lz conformer whose interactions with lipid bilayers are accompanied by the increase in membrane free volume; (ii) CPZ imparts the positive charge to the lipid bilayer thereby preventing Lz penetration into hydrophobic membrane region. Interfacially-located protein molecules are likely to generate structural defects coupled with the increased bilayer free volume. The results presented here clearly demonstrate that membrane composition can modulate the drug action on lipid-protein interactions. The recovered difference between CPZ effect on Lz-lipid binding in PC and CL-containing bilayers provide support to the idea that membrane environment can stabilize certain protein conformations differing in their responsiveness to drug action

Lipid-mediated lysozyme aggregation: furster resonance energy transfer study

Aggregation of proteins into insoluble complexes is intimately linked to pathogenesis of several neurodegenerative diseases. Protein aggregation is commonly regarded as nonspecific coagulation of incompletely folded or partially denaturated polypeptides, driven by interaction between the exposed hydrophobic patches. Accumulating evidence indicates that protein self-association can be induced by protein-lipid interactions. The present study addresses a problem of aggregation behavior of lysozyme (Lz) bound to model membranes composed of phosphatidylcholine (PC) and phosphatidylglycerol (PG) (8:2). The formation of Lz assemblies in lipid environment has been monitored by measuring steady-state resonance energy transfer (FRET). Several donor-acceptor pairs have been employed: tryptophan (Trp) – pyrene, pyrene – fluorescein 5’-isothiocyanate (FITC) and FITC – rhodamine-isothiocyanate (RITC). Fluorescence spectra of pyrene maleimide-labelled Lz (Lz-PM) recorded at different lipid-to-protein molar ratios (L:P) with excitation wavelength of 296 nm were featured by three bands corresponding to Trp, pyrene monomer and excimer emission. Analysis of the shape of emission spectra showed that the ratio of PM to Trp intensity rises with increasing Lz-PM concentration and decreasing L:P values from 379 to 77. This effect is most probably to arise from the enhanced FRET between Trp and pyrene. The finding that the magnitude of this effect depends on protein concentration suggests that FRET enhancement is caused by the formation of protein aggregates. The same result was obtained with Lz- attached pyrene as donor and Lz-attached FITC as acceptor – the efficiency of energy transfer increased with increasing total protein concentration and decreasing L:P. Notably, the most pronounced increase of energy transfer efficiency was observed at surface coverage ca. 38 lipids per one protein molecule suggesting that this L:P value is critical for formation of Lz self-associates. The assumption that Lz forms aggregates in membrane environment is also corroborated by the quantitative analysis of FRET between FITC and RITC. The distance between FITC and RITC was found to be ca. 8 nm which exceeds the dimensions of Lz molecule by 2-2.5 times, lending additional support to the idea about Lz self- association in lipid surroundings

Формування механізму реалізації державної фінансової політики в Україні

EN:Financial system was considered as an integration factor of aggregated elements of state economic system that provides accumulative property of financial resources and their mobility between subjects. This is possible, when the influence of financial policy of the state is taken out. As it defines the objective tendencies of growing share of the financial sector contribution to the gross domestic product, which drives the redistribution within the financial system funds involved in the form of foreign borrowing and foreign investment. It has been proved that an alternative model of development for implementation of financial policy of the state in the context of the financial system and the economic factors functioning provides optimal cost distribution of financial resources between businesses, households, industries, regions, and financial intermediaries. Designing the integrated approach to development for implementation of financial policy of the state’s distribution of budget transfers between entities of the financial system focused on corporate governing the financial resources, and is a common feature of the integrated aggregated elements of economic system. The mechanism of the financial system operation is considered as a set of tools for designing the strategic regulation, planning, financing and managing financial flows. This made ground for methodic support to the research and its meaningful component of financial support by the state and the impact of potential financial risks on the formation of alternative distribution and use of financial resources between entities on financial market. The elements of financial relations at the state level were segregated to create conditions for placing its own debt on the stock market, to attract resources to finance budget expenditures and debt management. It is suggested to consider fiscal policy as part of the implementation of financial policy of the state in the short term, aimed at the redistribution of the gross domestic product due to tax system, budget expenditure and social transfers. In the long run, fiscal policy should help boost economic development of the state through discretionary changes in economic stabilizers and regulators, thus providing a multiplier effect leveling the result of internal displacement lag and budget shortage. UK:Стаття присвячена обґрунтуванню засад формування та реалізації державної фінансової політики в Україні. Розглянуто фінансову систему як фактор інтеграції сукупних елементів економічної системи держави, який забезпечує акумулятивну властивість фінансових ресурсів та їх мобільність між суб’єктами. Розкрито механізм функціонування фінансової системи та обґрунтовано методичну складову формування державної фінансової підтримки. Виокремлено елементи фінансових відносин на державному рівні для формування умов розміщення власних боргових зобов’язань на фондовому ринку, залучення ресурсів для фінансування видатків бюджету, а також управління державним боргом. Запропоновано розглядати бюджетно-податкову політику як складову реалізації державної фінансової політики в короткостроковому періоді, спрямовану на перерозподіл валового внутрішнього продукту за системою оподаткування, бюджетних витрат та соціальних трансфертів. В довгостроковому періоді бюджетно-податкова політика повинна сприяти зростанню економічного розвитку країни через дискреційні зміни економічних стабілізаторів та регуляторів, забезпечуючи таким чином ефект мультиплікатора, нівелюючи ефект витіснення внутрішнього лагу, дефіцит бюджету

The nature of compensatory and restorative processes in the livers of animals irradiated during hypokinesia

The nature of postirradiation repair in the livers of rats irradiated during hypokinesia is investigated. Hepatocyte population counts, mitotic activity, binuclear cell content, and karyometric studies were done to ascertain the effects of combined hypokinesia and radiation. Hypokinesia is shown to change the nature and rate of post-irradiation changes in the liver, the effect varying with the timing of irradiation relative to the length of hypokinesia. It is concluded that the changes in the compensatory and restorative processes are caused by stress developed in response to isolation and restricted mobility. By changing neuroendocrine system activity, the stress stimulates cell and tissue repair mechanisms at a certain stage essential to the body's reaction of subsequent irradiation

Low-melting bismuth–borate glass: composition development

The properties of low-melting lead-free glass based on the system ZnO–Bi2O3–B2O3 with K2O, Al2O3, and SiO2 additions are studied experimentally and the results are presented. The complete spreading and softening temperature ranges are determined. The computed values of the CLTE and refractive indices of the glasses are presented. Conclusions are drawn concerning the structural state of the bismuth ions

Influence of oligomeric and fibrillar lysozyme on physical properties of model membranes

A pathological hallmark of more than 20 human diseases including Alzheimer’s disease, Parkinson’s disease, type II diabetes is the deposition in organs and tissues of insoluble highly ordered protein aggregates, called amyloid fibrils. It is becoming widely recognized that toxicity of amyloid species is related to their interactions with cell membranes. In the present study we focused our efforts on the examination of the influence of amyloid fibrils and their precursors (oligomeric aggregates) of lysozyme on the structural and physical properties of the model membranes composed of phosphatidylcholine and its mixture with cholesterol. For evaluating the extent of lipid bilayer modifications, we used fluorescence spectroscopy technique. The results of pyrene excimerization measurements showed that amyloid protein reduces membrane fluidity. Analysis of Laurdan emission spectra revealed the ability of lysozyme aggregates to produce bilayer dehydration. The most pronounced membrane-modifying effects were observed in the case of oligomeric lysozyme. Significantly less influence of pathogenic protein aggregates on the physical properties of cholesterol-containing vesicles confirmed the hypothesis on the preventive role of cholesterol in amyloid-related diseases

Структура совокупного финансового потенциала сельского хозяйства: региональный аспект

EN: The purpose of the article is to form the architectural structure of the total financial potential of agriculture and to substantiate the predictive resource parameters of financial security of the regions of the agro-climatic zones of the Steppe of Ukraine. The components of the aggregate financial potential of agriculture at the regional level are determined, which are capable by certain properties of its objects, to perform actions to mobilize the real and hidden possibilities of financial resources in a limited time period. The method of inductive system analysis and simulation modeling was used to determine the influence of system factors of the aggregate financial potential of agriculture on the formation of generalized integrated index of its level in the regions of the agroclimatic zone of the Steppe of Ukraine. A predictive simulation model of a stable level of financial potential of the region is developed that allows for net income and net profit to ensure the efficient use of financial resources of agricultural enterprises. The proposed model is adequate, its statistical significance and reliability are sufficient for use in forecasting the level of financial potential of the region. Realization of the model provides reserve of the volume of own financial resources, increases profitability of business entities, forms external and internal incentives for agricultural development at the regional level. UK: Метою статті є формування архітектоніки сукупного фінансового потенціалу сільського господарства та обґрунтування прогнозних ресурсних параметрів фінансової безпеки регіонів агрокліматичних зон Степу України. Визначено складові сукупного фінансового потенціалу сільського господарства на регіональному рівні, які здатні за певних властивостей його об’єктів, виконувати дії з мобілізації реальних та прихованих можливостей фінансових ресурсів в обмеженому часовому періоді. Застосовано методику індуктивного системного аналізу та імітаційного моделювання для визначення впливу системних факторів сукупного фінансового потенціалу сільського господарства на формування узагальненого інтегрального показника його рівня в регіонах агрокліматичної зони Степу України. Розроблено прогнозну імітаційну модель стабільного рівня фінансового потенціалу регіону, яка дозволяє за чистим доходом та чистим прибутком забезпечити ефективність використання фінансових ресурсів сільськогосподарських підприємств. Запропонована модель є адекватною, її статистична значущість і достовірність достатні для використання у прогнозуванні рівня фінансового потенціалу регіону. Реалізація моделі забезпечує резервування обсягу власних фінансових ресурсів, підвищує прибутковість діяльності суб’єктів господарювання, формує зовнішні і внутрішні стимули розвитку сільського господарства на регіональному рівні. RU: Целью статьи является формирование архитектоники совокупного финансового потенциала сельского хозяйства и обоснование прогнозных ресурсных параметров финансовой безопасности регионов агроклиматических зон Степи Украины. Определены составляющие совокупного финансового потенциала сельского хозяйства на региональном уровне, которые способны с определенными свойствами его объектов, выполнять действия по мобилизации реальных и скрытых возможностей финансовых ресурсов в ограниченном временном периоде. Применена методика индуктивного системного анализа и имитационного моделирования для определения влияния системных факторов совокупного финансового потенциала сельского хозяйства на формирование обобщенного интегрального показателя его уровня в регионах агроклиматической зоны Степи Украины. Разработана прогнозная имитационная модель стабильного уровня финансового потенциала региона, которая позволяет по чистому доходу и чистой прибыли обеспечить эффективность использования финансовых ресурсов сельскохозяйственных предприятий. Предложена модель является адекватной, ее статистическая значимость и достоверность достаточны для применения в прогнозировании уровня финансового потенциала региона. Реализация модели обеспечивает резервирование объема собственных финансовых ресурсов, повышает прибыльность деятельности субъектов хозяйствования, формирует внешние и внутренние стимулы развития сельского хозяйства на региональном уровне

Resonance energy transfer study of hemoglobin binding to model lipid membranes

In the present study fluorescence resonance energy transfer (FRET) technique was employed to obtain the information about the structure of hemoglobin (Hb) complexes with model lipid membranes of different composition. For this purpose three membrane probes, 3-methoxybenzanthrone (MBA), 4- dimethylaminochalcone (DMC) and 6-propionyl-2-dimethylaminonaphthalene (Prodan) were assessed as possible donors for heme moiety of the protein. Model membranes were composed of zwitterionic lipid phosphatidylcholine (PC), anionic lipid cardiolipin (CL) and cholesterol (Chol). FRET measurements were interpreted in terms of the model of energy transfer in two-dimensional systems proposed by Fung and Stryer and further extended by Davenport et al. No FRET was observed between Prodan and Hb because Prodan under the employed experimental conditions was not distributed into the lipid bilayer. In the case of DMC, Hb-induced oxidative processes in the lipid phase hampered the estimation of Hb location in a lipid bilayer. Therefore, structural analysis of Hb-lipid complexes was carried out using MBA as a donor. First, the donor quantum yield, Fцrster radii and fluorescence anisotropy of the probes have been measured. Second, the amount of Hb bound to model membranes was estimated in terms of the lattice models of large ligand adsorption to lipid bilayers allowing for the possibility of protein insertion into membrane interior. Finally, the distance from acceptor plane to the bilayer center and the depth of Hb penetration into lipid bilayer were calculated. It was assumed that protein binds to membranes in the form of dimers and penetrates into the membrane interior. In neutral liposomes Hb penetrates only to the depth of lipid headgroups. The observed higher extent of Hb penetration into Chol containing bilayer as compared to PC liposomes may be a consequence of specific Hb-Chol interaction. In the case of PC/CL liposomes Hb was found to insert in the non-polar membrane region. Taking into account the possibility of forming the inverted hexagonal structures in the presence of CL, it cannot be excluded that Hb being entrapped in such structures, translocates through the membrane. If this phenomenon takes place, deeper Hb penetration into lipid bilayer might be expected. The obtained results can be useful for exact characterization of Hb binding to the membranes