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1
Content available remote

Hypothesis: cell volume limits cell divisions

100%
Biliński T., Bartosz G.
|
2006
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vol. 53
|
issue 4
833-835
EN
Mammalian somatic cells and also cells of the yeast Saccharomyces cerevisiae are capable of undergoing a limited number of divisions. Reaching the division limit is referred to, apparently not very fortunately, as replicative aging. A common feature of S. cerevisiae cells and fibroblasts approaching the limit of cell divisions in vitro is attaining giant volumes. In yeast cells this phenomenon is an inevitable consequence of budding so it is not causally related to aging. Therefore, reaching a critically large cell volume may underlie the limit of cell divisions. A similar phenomenon may limit the number of cell divisions of cultured mammalian cells. The term replicative (generative) aging may be therefore illegitimate.
2
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Determination of antiradical and antioxidant activity: basic principles and new insights

100%
Tirzitis G., Bartosz G.
|
2010
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vol. 57
|
issue 2
139-142
EN
Although the term 'antioxidant' is used very frequently, there are problems with the definition of antioxidants and estimation of antioxidant activity. The distinction between antioxidant and antiradical activities is not always obvious. This minireview discusses critically the principles, advantages and limitations of the most frequently used methods of estimation of antiradical and antioxidant activities.
3
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Content available

Spin-labeled analogs of biologically active compounds

100%
Gwoździński K., Bartosz G., University of Łódź I. o. B. a. B.
Acta Universitatis Lodziensis. Folia Biochimica et Biophysica
|
1981
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vol. 1
PL
Omówiono syntezę i zastosowanie różnych rodzajów znakowanych spinowo związków biologicznie czynnych. Poszczególne klasy tych związków obejmują: sulfonamidy, antybiotyki, witaminy, związki znieczulające i estry choliny, alkaloidy i leki przeciwnowotworowe.
4
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Relationship between the replicative age and cell volume in Saccharomyces cerevisiae

81%
Zadrag R., Kwolek-Mirek M., Bartosz G., Bilinski T.
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2006
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vol. 53
|
issue 4
747-751
EN
Reaching the limit of cell divisions, a phenomenon referred to as replicative aging, of the yeast Saccharomyces cerevisiae involves a progressive increase in the cell volume. However, the exact relationship between the number of cell divisions accomplished (replicative age), the potential for further divisions and yeast cell volume has not been investigated thoroughly. In this study an increase of the yeast cell volume was achieved by treatment with pheromone α for up to 18 h. Plotting the number of cell divisions (replicative life span) of the pheromone-treated cells as a function of the cell volume attained during the treatment showed an inverse linear relationship. An analogous inverse relationship between the initial cell volume and replicative life span was found for the progeny of the pheromone-treated yeast. This phenomenon indicates that attaining an excessive volume may be a factor contributing to the limitation of cellular divisions of yeast cells.
5
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Reakcja fentona

81%
Sadowska-Bartosz I., Galiniak S., Bartosz G.
Kosmos
|
2014
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vol. 63
|
issue 3
309-314
PL
Toksyczność żelaza jest uwarunkowana reakcją Fentona czyli tworzeniem rodników hydroksylowych w reakcji z nadtlenkiem wodoru. Artykuł przedstawia skrótowo historię odkrycia Fentona, kontrowersję dotyczącą natury reaktywnego oksydanta tworzonego w reakcji Fentona, reaktywność rodnika hydroksylowego, udział jonów innych metali w reakcji Fentona i wykorzystanie reakcji Fentona do oczyszczania ścieków.
EN
The toxicity of iron is mainly due to the Fenton reaction i. e. formation of hydroxyl radicals in a reaction with hydrogen peroxide. The paper presents briefly the history of Fenton discovery, the controversy regarding the nature of the reactive oxidant formed in the Fenton reaction, the reactivity of the hydroxyl radical, participation of other metal ions in the Fenton reaction and the application of the Fenton reaction for wastewater treatment.
6
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Reactive oxygen species are formed in cell culture media. (Letter to the Editor)

81%
Grzelak A., Rychlik B., Bartosz G.
|
2000
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vol. 47
|
issue 4
1197-1198
7
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Modification of the deoxyribose test to detect strong iron binding

81%
Sadowska-Bartosz I., Galiniak S., Bartosz G.
|
2017
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vol. 64
|
issue 1
195-198
EN
Deoxyribose test has been widely used for determination of reactivities of various compounds for the hydroxyl radical. The test is based on the formation of hydroxyl radical by Fe2+ complex in the Fenton reaction. We propose a modification of the deoxyribose test to detect strong iron binding, inhibiting participation of Fe2+ in the Fenton reaction, on the basis of examination of concentration dependence of deoxyribose degradation on Fe2+ concentration, at a constant concentration of a chelating agent.
8
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Transport of organic anions by multidrug resistance-associated protein in the erythrocyte.

71%
Rychlik B., Pułaski Ł., Sokal A., Soszyński M., Bartosz G.
|
2000
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vol. 47
|
issue 3
763-772
EN
The active transport of oxidized glutathione and glutathione S-conjugates has been demonstrated for the first time in erythrocytes and this cell remained the main subject of research on the "glutathione S-conjugate pump" for years. Further studies identified the "glutathione S-conjugate pump" as multidrug resistance-associated protein (MRP). Even though cells overexpressing MRP and isolated MRP provide useful information on MRP structure and function, the erythrocyte remains an interesting model cell for studies of MRP1 in its natural environment, including the substrate specificity and ATPase activity of the protein.
9
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Developmental changes in the levels and redox potentials of main hemolymph thiols/disulfides in the Jamaican field cricket Gryllus assimilis

71%
Sadowska-Bartosz I., Furmaniak P., Bieszczad-Bedrejczuk E., Bartosz G., Głowacki R.
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2017
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vol. 64
|
issue 3
503-506
EN
Main thiols and disulfides were determined in the hemolymph of the Jamaican field cricket Gryllus assimilis at various developmental stages. On the basis of these data, redox potentials of the glutathione, cysteine and homocysteine redox systems were calculated. The concentrations of all thiols studied decreased during development (at a stage of 6 molts) with respect to young crickets, and increased again in adult insects. Redox potentials of the glutathione and cysteine systems increased from values of -131.0±5.6 mV and -86.9±17.1 mV, respectively in young crickets to -58.0±3.6 mV and -36.1±4.2 mV, respectively, at the stage of 6 molts and decreased to values of -110.4±24.8 mV and -66.3±12.2 mV, respectively, in adult insects. Redox potentials of the glutathione and cysteine systems in the hemolymph of young and adult insects were similar to those reported for human plasma.
10
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Effect of stress on the life span of the yeast Saccharomyces cerevisiae.

71%
Święciło A., Krawiec Z., Wawryn J., Bartosz G., Biliński T.
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2000
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vol. 47
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issue 2
355-364
EN
A correlation is known to exist in yeast and other organisms between the cellular resistance to stress and the life span. The aim of this study was to examine whether stress treatment does affect the generative life span of yeast cells. Both heat shock (38°C, 30 min) and osmotic stress (0.3 M NaCl, 1 h) applied cyclically were found to increase the mean and maximum life span of Saccharomyces cerevisiae. Both effects were more pronounced in superoxide dismutase-deficient yeast strains (up to 50% prolongation of mean life span and up to 30% prolongation of maximum life span) than in their wild-type counterparts. These data point to the importance of the antioxidant barrier in the stress-induced prolongation of yeast life span.
11
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Antisense hairpin loop oligonucleotides as inhibitors of expression of multidrug resistance-associated protein 1: Their stability in fetal calf serum and human plasma.

62%
Rębowski G., Wójcik M., Boczkowska M., Gendaszewska E., Soszyński M., Bartosz G., Niewiarowski W.
|
2001
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vol. 48
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issue 4
1061-1076
EN
Multidrug resistance-associated protein (MRP1) is a transmembrane pump protein responsible for the efflux of chemotherapeutic drugs, an important cause of anticancer treatment failure. Trying to circumvent MRP-mediated resistance we designed and synthesized hairpin loops forming antisense oligodeoxyribonucleotides (ODNs), both phosphodiesters (PO-ODNs) and their phosphorothioate analogues (PS-ODNs), to reduce the protein expression by targeting its mRNA in a sequence specific manner. Melting temperature measurements as well as polyacrylamide gel electrophoresis supported the preferential formation of a secondary structure, which was expected to protect ODNs against 3'-exonuclease degradation. ODNs and PS-ODNs designed in this work were successfully tested as antisense inhibitors of the expression of MRP1 in the leukaemia HL60/ADR cell line. Foreseeing the necessity to perform clinical studies with such ODNs we investigated their stability against the 3'-exonuclease activity of fetal calf serum and human plasma. Under the conditions, corresponding to physiological ones, we observed high stability of hairpin loop forming ODNs, especially those containing longer (e.g. 7 base pair) stems. Comparative studies on the stability of chemically unmodified hairpin loop forming ODNs and their PS-counterparts indicated that endonuclease activity did not play any important role in the process of their nucleolytic degradation. Our studies provide strong evidence for high stability of chemically unmodified hairpin loop ODNs, making them an attractive alternative to phosphorothioate analogues commonly used in antisense strategy.
12
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Multidrug resistance-associated protein - reduction of expression in human leukaemia cells by antisense phosphorothioate olignucleotides.

62%
Niewiarowski W., Gendaszewska E., Rębowski G., Wójcik M., Mikołajczyk B., Soszyński M., Bartosz G.
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2000
|
vol. 47
|
issue 4
1183-1188
EN
Multidrug resistance-associated protein (MRP1) causes cellular drug resistance in several cancer cell lines. In this paper we show that antisense oligonucleotides decrease MRP1 expression in human leukaemia cells. We investigated biological activity of a series of 12 linear phosphorothioate oligonucleotides, complementary to several regions of MRP1 mRNA. The oligonucleotides were administered to leukaemia HL60/ADR cells overexpressing MRP1 protein. Then, the level of MRP1 mRNA was determined by means of semiquantitative RT-PCR and the protein level by reaction with specific monoclonal antibodies. Some of the investigated antisense oligonucleotides decrease the expression level of the MRP1 protein by 46% and its mRNA level by 76%.
13
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Yeast as a biosensor for antioxidants: simple growth tests employing a Saccharomyces cerevisiae mutant defective in superoxide dismutase

62%
Żyracka E., Zadrąg R., Kozioł S., Krzepiłko A., Bartosz G., Biliński T.
|
EN
Mutants of Saccharomyces cerevisiae devoid of Cu,Zn-superoxide dismutase are hypersensitive to a range of oxidants, hyperbaric oxygen and hyperosmotic media, show lysine and methionine auxotrophy when grown under the atmosphere of air and have a shortened replicative life span when compared to the wild-type strain. Ascorbate and other antioxidants can ameliorate these defects, which may be a basis of simple tests sensing the presence of antioxidants. In particular, tests of growth on solid medium (colony formation) in the absence of methionine and/or lysine, or in the presence of 0.8 M NaCl can be useful for detection and semiquantitative estimation of compounds of antioxidant properties. Hypoxic atmosphere was found to increase the sensitivity of detection of antioxidants. The test of abolishment of lysine auxotrophy showed a concentration dependence of the antioxidant effects of cysteine and N-acetylcysteine which, however, lost their protective action at high concentration, in contrast to glutathione which was effective also at higher concentrations.
14
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Peroxynitrite: mediator of the toxic action of nitric oxide

60%
Bartosz G.
Acta Biochimica Polonica
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1996
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vol. 43
|
issue 4
645-659
15
Content available remote

Antioxidant activity: what do we measure?

50%
Bartosz G., Bartosz M.
Acta Biochimica Polonica
|
1999
|
vol. 46
|
issue 1
23-29
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