Effect of phosphatidylcholine chlorohydrins on human erythrocytes

Hypochlorite generated in vivo under pathological conditions is a known oxidant and chlorinating agent, able to react with proteins and lipids, which affects the stability of biological membranes. Reaction with unsaturated fatty acyl chains in glycerophospholipids such as phosphatidylcholine results in the formation of chlorohydrins. The aim of this study was to determine the effects of chlorohydrins formed by the reaction of hypochlorite with 1-stearoyl-2-oleoyl-, 1-stearoyl-2-linoleoyl-, and 1-stearoyl-2-arachidonylphosphatidylcholine on biophysical properties of bilayers and their effects on human erythrocytes. Using electrospray mass spectrometry we observed complete conversion of the lipids into chlorohydrins, which resulted in a decrease in the rotational correlation time and an increase in the order parameter of liposomes. Unilamellar chlorohydrin liposomes had a lower permeation coefficient for calcein than liposomes made of parent lipids. Flow cytometry demonstrated fast incorporation of uni and multilamellar chlorohydrin liposomes labeled with NBD-phosphatidylethanolamine into erythrocytes. This effect was accompanied by changes in erythrocyte shape (echinocyte formation) and aggregation. Similar but less pronounced effects were noticed for parent lipids only after longer incubation. Chlorohydrins showed also a stronger hemolytic action, proportional to the lipid:erythrocyte ratio. These results are important for understanding the effects of HOCl on mammalian cells, such as might occur in inflammatory pathology.

An inter-laboratory validation of methods of lipid peroxidation measurement in UVA-treated human plasma samples

Lipid peroxidation products like malondialdehyde, 4-hydroxynonenal and F(2)-isoprostanes are widely used as markers of oxidative stress in vitro and in vivo. This study reports the results of a multi-laboratory validation study by COST Action B35 to assess inter-laboratory and intra-laboratory variation in the measurement of lipid peroxidation. Human plasma samples were exposed to UVA irradiation at different doses (0, 15 J, 20 J), encoded and shipped to 15 laboratories, where analyses of malondialdehyde, 4-hydroxynonenal and isoprostanes were conducted. The results demonstrate a low within-day-variation and a good correlation of results observed on two different days. However, high coefficients of variation were observed between the laboratories. Malondialdehyde determined by HPLC was found to be the most sensitive and reproducible lipid peroxidation product in plasma upon UVA treatment. It is concluded that measurement of malondialdehyde by HPLC has good analytical validity for inter-laboratory studies on lipid peroxidation in human EDTA-plasma samples, although it is acknowledged that this may not translate to biological validity.

Sensitivity of antioxidant-deficient yeast to hypochlorite and chlorite

Sodium hypochlorite and sodium chlorite are commonly used as disinfectants, and understanding the mechanisms of microbial resistance to these compounds is of considerable importance. In this study, the role of oxidative stress and antioxidant enzymes in the sensitivity of the yeast Saccharomyces cerevisiae to hypochlorite and chlorite was studied. Yeast mutants lacking Cu-Zn superoxide dismutase, but not mutants deficient in cytoplasmic and peroxisomal catalase, were hypersensitive to the action of both hypochlorite and chlorite. Both compounds depleted cellular glutathione, induced the production of reactive oxygen species and decreased the viability of the cells. The toxicity of hypochlorite and chlorite was abolished by hypoxic and anoxic conditions and ameliorated by thiol antioxidants and ascorbate. The results demonstrated that the action of hypochlorite and chlorite involves the formation of superoxide and peroxide and that SOD1 is protective, probably by limiting the formation of hydroxyl radicals and damage to proteins.

HOCl-modified phosphatidylcholines induce apoptosis and redox imbalance in HUVEC-ST cells

Electrophilic attack of hypochlorous acid on unsaturated bonds of fatty acyl chains is known to result mostly in chlorinated products that show cytotoxicity to some cell lines and were found in biological systems exposed to HOCl. This study aimed to investigate more deeply the products and the mechanism underlying cytotoxicity of phospholipid-HOCl oxidation products, synthesized by the reaction of HOCl with 1-stearoyl-2-oleoyl-, 1-stearoyl-2-linoleoyl-, and 1-stearoyl-2-arachidonyl-phosphatidylcholine. Phospholipid chlorohydrins were found to be the most abundant among obtained products. HOCl-modified lipids were cytotoxic towards HUVEC-ST (endothelial cells), leading to a decrease of mitochondrial potential and an increase in the number of apoptotic cells. These effects were accompanied by an increase of the level of active caspase-3 and caspase-7, while the caspase-3/-7 inhibitor Ac-DEVD-CHO dramatically decreased the number of apoptotic cells. Phospholipid-HOCl oxidation products were shown to affect cell proliferation by a concentration-dependent cell cycle arrest in the G/G phase and activating redox sensitive p38 kinase. The redox imbalance observed in HUVEC-ST cells exposed to modified phosphatidylcholines was accompanied by an increase in ROS level, and a decrease in glutathione content and antioxidant capacity of cell extracts. © 2014 Elsevier Inc. All rights reserved.

Effect of different doses of post-emergence-applied iodosulfuron on weed control and grain yield of malt barley (Hordeum distichum L.), under Mediterranean conditions

A study was carried out over a two year period (2009/2010 and 2012/2013) on an experimental farm in the Alentejo region (Beja), in southern Portugal where rainfed malt barley (Hordeum distichum L.) is sown at the end of autumn or beginning of winter (November– December). The aim of this experiment was to study the efficiency of the herbicide iodosulfuron-methyl-sodium to control post-emergence broadleaved weeds in this cereal crop. The malt barley crop was established using no-till farming. This technology provides the necessary machine bearing capacity of the soil to assure the post-emergence application of herbicides at two diferente weed development stages. The herbicide iodosulfuron-methyl-sodium was applied at three doses (5.0, 7.5, and 10.0 g a. i. · ha–1) and at two different broadleaved weed development stages (3 to 4 and 6 to 7 pairs of leaves), that also corresponded to two diferente crop development stages (beginning of tillering and complete tillering). The results indicated that early herbicide application timing provided a significantly higher efficiency for all the applied herbicide doses, but this better weed control was not reflected in a higher crop grain yield. The lack of a higher crop grain yield was probably due to a crop phytotoxicity of the herbicide, when used at an early application timing.

Filmowe interpretacje polskiej transformacji gospodarczej. Kulturowe spory o obraz Polski

Wydział Nauk Społecznych: Instytut Kulturoznawstwa

AtDeg2 – a chloroplast protein with dual protease/chaperone activity

Chloroplast protease AtDeg2 (an ATP-independent serine endopeptidase) is cytosolically synthesized as a precursor, which is imported into the chloroplast stroma and deprived of its transit peptide. Then the mature protein undergoes routing to its functional location at the stromal side of thylakoid membrane. In its linear structure AtDeg2 molecule contains the protease domain with catalytic triad (HDS) and two PDZ domains (PDZ1 and PDZ2). In vivo AtDeg2 most probably exists as a supposedly inactive haxamer, which may change its oligomeric stage to form active 12-mer, or 24-mer. AtDeg2 has recently been demonstrated to exhibit dual protease/chaperone function. This review is focused on the current awareness with regard to AtDeg2 structure and functional significance.

Plejotropowe działanie neuropeptydów allatostatynowych w regulacji procesów fizjologicznych u chrząszczy

Wydział Biologii

El discurso político en el contexto multicultural de las instituciones de la Unión Europea. El discurso político en español y en polaco

The comparative analysis of Polish and Spanish political discourse in the multilingual context of European institutions is challenging not only due to linguistic, cultural, geopolitical and social differences, but also because of a relatively short history of such contacts in the EU framework. Intercultural communication, as a dynamic social practice is a fascinating object of investigation. Bidirectional comparative analysis of Polish and Spanish oral texts allows define the barriers of such communication. It encompasses the discursive act together with its objectives, strategies and consequences, and also its raison d’être. It explains why different strategies reflected through discursive categories were used. Consequently it describes both, conditions and outcomes of identity negotiation. The latter is a political competence perceived and evaluated by the direct interlocutors, the participants of the political debate, and indirectly, by a public opinion of the European Union. That proves it is two-level communication. The negotiation of political identity through discourse, according to the Ting-Toomey theory, can lead to maintaining, loosing, recovering or reinforcing it282. The Identity Negotiation Theory includes the construction and development of personal, relational, role and desired identity and is one of the methodological axes of this investigation. Political identity consists of exhibiting necessary competences to efficiently participate in the legislation process, for example, in order to present amendments, promote a given ideology, participate in controversial discussions and manage conflicts, and, finally, gain the support of public opinion. The analysis of creation, negotiation, maintenance, recovery and promotion of the political identity is performed through the identification and description of discursive categories proposed by Van Dijk283 and adapted to the needs of this study. This is the second methodological axe of the investigation. The following questions arise: which discursive strategies, used by Polish and Spanish politicians, will be communication facilitators and which will be barriers hampering communication? Which strategies show political competencies of the speaker, his or her influence in the legal EU reality through discourse?...

Towards a 21st-century roadmap for biomedical research and drug discovery: consensus report and recommendations

Decades of costly failures in translating drug candidates from preclinical disease models to human therapeutic use warrant reconsideration of the priority placed on animal models in biomedical research. Following an international workshop attended by experts from academia, government institutions, research funding bodies, and the corporate and nongovernmental organisation (NGO) sectors, in this consensus report, we analyse, as case studies, five disease areas with major unmet needs for new treatments. In view of the scientifically driven transition towards a human pathway-based paradigm in toxicology, a similar paradigm shift appears to be justified in biomedical research. There is a pressing need for an approach that strategically implements advanced, human biology-based models and tools to understand disease pathways at multiple biological scales. We present recommendations to help achieve this.

Una aproximación a la cosmovisión y a la historia de occidente en la obra ensayística de Czeslaw Milosz

This thesis aims to identify the world-view of Czesław Miłosz as it underlies his work; a world-view which comprises historical, philosophical and theological perspectives. With this aim an analysis has been made of the books of essays and the collections of articles of the Polish writer. These form a major part of his literary production: twenty seven of the thirty eight volumes. The work The Land of Urlo (1977) has a special relevance to this endeavour. Two principal hypotheses have been formulated: 1. The world-view of Czesław Miłosz grew out of the assimilation of a series of intellectual influences. The catholic education in his childhood. The encounter in his youth with the gnostic Christian Oskar Miłosz and with Marxism. His contact during the period of the Second Word War and at the beginning of its sequel with the hegelian philosopher Tadeusz Kroński. This world-view had crystalized during his exile. From then he completed his reading of Simone Weil, Emanuel Swedenborg, and William Blake. 2. The world-view of Czesław Miłosz is directly related to his understanding of the History of the West from the beginnings of Christianity to contemporary times. The difficulty in understanding the Weltanschauung of Czesław Miłosz is not of a technical nature (expression in an excessively complex language, dispersion of his work in multifarious archives, collections of letters, etc.). It arises – and only to a lesser degree in his political and philosophical-religeous and biographical essays – out of the author's use of a cryptic language with the intention of hiding a part of his message from view...