Wyniki wyszukiwania - Biblioteka Nauki

1

Differences in basal DNA damage in blood cells from men and women

100%

Alija A. J. , Collins A. R. , Dreshaj S. , Asllani F. , Bajraktari I. D. , Bresgen N. , Eckl P. M.

Biomonitoring

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2016

|

tom 3

|

nr 1

EN

We have recently shown that inhabitants of two polluted areas in Kosovo display more DNA damage (strand breaks in blood cell DNA) than do residents of a cleaner area. Here, we present additional analyses of these data and discuss additional data sets from Kosovo. Based on our data as well as the available data from other authors, age and sex-related differences in DNA damage or in susceptibility to DNA-damaging agents in the environment should be carefully considered when designing biomonitoring studies and when carrying out statistical analysis of the data.

2

5',8-Cyclo-2'-deoxyadenosine (cdA) formation by γ-radiation. Theoretical quantum mechanics study

100%

Karwowski B. , Grand A. , Cadet J.

Acta Biochimica Polonica

|

2009

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tom 56

|

nr 4

655-662

EN

Reactions of reactive oxygen species and more specifically - of hydroxyl radical (•OH) - with nucleosides may lead to the generation of radicals in the base and 2-deoxyribose moieties. In the present study emphasis was put on the possible reaction modes of 2'-deoxyadenosine (dA) radicals, leading to the formation of related 5',8-cyclonucleosides. It appears that the prerequisite for the formation of 5',8-cyclo-2'-deoxyadenosine (cdA) is the adoption of O4'-exo conformation by 2-deoxyribose; however, this is the least energetically favored conformer among the different puckered forms adopted by the furanose ring. The O4'-exo conformation was found to be present in each of the discussed mechanisms.

3

Atmospheric pollution in Kosovo is associated with increased DNA damage in the human population

100%

Alija A. J. , Asllani F. , Bajraktari I. D. , Collins A. R. , Dreshaj S. , Bresgen N. , Eckl P. M.

Biomonitoring

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2015

|

tom 2

|

nr 1

EN

In order to assess DNA damage associated with exposure to environmental pollution in two polluted sites and one control site in Kosovo, whole blood samples were collected from volunteers in two polluted areas (Kastriot/ Obiliq - lignite-based power plants and lignite mines - and Drenas/Gllogovc - Ferronikeli smelting plant) as well as from Peja, representing an unpolluted area. White blood cells were isolated, and DNA damage was analyzed by the alkaline comet assay. Significantly higher levels of DNA damage (strand breaks) were found in white blood cells from subjects living in the polluted areas compared with residents of the unpolluted city, indicating a potential threat to human health.

4

Age-dependent systemic DNA damage in early Type 2 Diabetes mellitus

100%

Rogulj D. , El Aklouk I. , Konjevoda P. , Ljubić S. , Pibernik Okanović M. , Barbir A. , Luburić M. , Radman M. , Budinski N. , Vučić Lovrenčić M.

Acta Biochimica Polonica

|

2017

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tom 64

|

nr 2

233-238

EN

Oxidative stress, capable of eliciting damage to various biomolecules including DNA, is a recognized component of diabetes mellitus and its complications. Metabolic syndrome (MetS) is associated with the development of type 2 diabetes mellitus (T2DM), as well as other unfavorable outcomes. The aim of this study was to elucidate the role of oxidative stress in the development of T2DM, by investigating association of oxidative DNA damage with metabolic parameters in subjects with MetS and early T2DM. Selected anthropometric and biochemical parameters of MetS, inflammation and oxidative DNA damage: body mass index (BMI), fatty liver index (FLI), waist circumference (WC), total cholesterol, HDL and LDL-cholesterol, gamma-glutamyl transpeptidase (GGT), uric acid, C-reactive protein (CRP), total leukocyte/neutrophil count, and urinary 8-hidroxy-deoxyguanosine (u-8-OHdG) were assessed in male subjects with MetS and both younger (≤55 years) and older (>55 years) subjects with T2DM of short duration without complications. BMI, FLI, WC, total and LDL-cholesterol and uric acid were higher, while the u-8-OHdG was lower in MetS group, when compared to older T2DM subjects. None of these parameters were different neither between MetS and younger T2DM, nor between two sub-groups of subjects with T2DM. Values of CRP, HDL-cholesterol, triglycerides, GGT, leukocytes and neutrophils were not different between all examined groups of subjects. Higher 8-OHdG in older subjects with T2DM suggests that both aging process and diabetes could contribute to the development of DNA damage. Oxidative DNA damage cannot serve as an universal early marker of T2DM.

5

A new look at adaptive mutations in bacteria.

100%

Janion C.

Acta Biochimica Polonica

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2000

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tom 47

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nr 2

451-457

EN

This is a short survey of the adaptive mutation processes that arise in non- or slowly- dividing bacterial cells and includes: (i) bacterial models in which adaptive mutations are studied; (ii) the mutagenic lesions from which these mutations derive; (iii) the influence of DNA repair processes on the spectrum of adaptive mutations. It is proposed that in starved cells, likely as during the MFD phenomenon, lesions in tRNA suppressor genes are preferentially repaired and no suppressor tRNAs are formed as a result of adaptive mutations. Perhaps the most provocative proposal is (iv) a hypothesis that the majority of adaptive mutations are selected in a pre-apoptotic state where the cells are either mutated, selected, and survive, or they die.

6

Detection of alkylation damage in human lymphocyte DNA with the comet assay.

100%

Collins A. R. , Dušinská M. , Horská A.

Acta Biochimica Polonica

|

2001

|

tom 48

|

nr 3

611-614

EN

The enzyme 3-methyladenine DNA glycosylase II (AlkA) is a bacterial repair enzyme that acts preferentially at 3-methyladenine residues in DNA, releasing the damaged base. The resulting baseless sugars are alkali-labile, and under the conditions of the alkaline comet assay (single cell gel electrophoresis) they appear as DNA strand breaks. AlkA is not lesion-specific, but has a low activity even with undamaged bases. We have tested the enzyme at different concentrations to find conditions that maximise detection of alkylated bases with minimal attack on normal, undamaged DNA. AlkA detects damage in the DNA of cells treated with low concentrations of methyl methanesulphonate. We also find low background levels of alkylated bases in normal human lymphocytes.Single cell gel electrophoresis (the comet assay) is widely used for the detection of strand breaks in nuclear DNA. It is particularly appropriate for studying the low background levels of damage present in normal human cells, such as peripheral lymphocytes. The cells are embedded in agarose on a microscope slide and lysed with Triton X-100 and 2.5 M NaCl, which remove cytoplasm and most nuclear proteins, but leave the DNA, in supercoiled form, as nucleoids. After incubation in alkali, the DNA is electrophoresed at high pH; DNA is drawn out to form a 'tail' (hence the name 'comet assay') - but only if breaks are present to relax the supercoiling of the nucleoid DNA. In order to increase its sensitivity and selectivity, we have incorporated into the assay an extra step in which the nucleoid DNA is digested with a lesion-specific endonuclease; the additional breaks revealed with this procedure indicate the presence of the particular lesion. So far, endonuclease III (NTH, specific for oxidised pyrimidines) (Collins et al., 1993), formamidopyrimidine DNA glycosylase (FPG, acting on ring-opened purines and the major purine oxidation produce, 8-oxoguanine) (Dušinská & Collins, 1996) and T4 endonuclease V (recognising UV-induced cyclobutane pyrimidine dimers) (Collins et al., 1997b) have been successfully employed. Amongst other things, we have estimated background levels of DNA oxidation (Collins et al., 1997a), and have found this damage to be elevated in human diseases such as diabetes and ankylosing spondylitis (Dušinská et al., 1999).We now report the use of AlkA, a bacterial repair enzyme whose main substrate is 3-methyladenine in DNA, though it also recognises - with lower efficiency - other modified bases (Lindahl, 1993). A recent report (Berdal et al., 1998) suggests that repair enzymes supposedly specific for alkylated bases may in fact create breaks non-selectively (though much less efficiently) at normal bases. Given the size of the genome, even a low efficiency of non-specific breakage could significantly interfere in estimations of background levels of alkylation damage. We reasoned that, by employing a range of concentrations of the enzyme, and carrying out incubations for different lengths of time, we might find a concentration at which only the alkylated bases would be detected, so that the number of breaks would increase to a certain level and then plateau. After optimising reaction conditions, we tested the assay on lymphocytes from different individuals, and also, as a positive control, examined alkylation damage induced by methyl methanesulphonate.

7

Mechanisms of DNA damage and repair, studied during the cell cycle

100%

Rzeszowska J.

Cellular and Molecular Biology Letters

|

2002

|

tom 07

|

nr Suppl.

8

The influence of the phosphorothioate diester bond on the DNA oxidation process

88%

Karwowski B. T.

Open Chemistry

|

2015

|

tom 13

|

nr 1

EN

This study describes the influence of the phosphorothioate internucleotide bond on the deoxyribonucleic acid (DNA) oxidation process. The interaction of an ultraviolet radiation (UVA) with a targeted double-stranded (ds) oligonucleotide, in which one strand contains an antraquinone (AQ) moiety on the 5’-end, may lead to a hole migration process through the double helix. In the end, the migration of theformed radical cation terminates in a suitable place. Usually, this is a guanine-rich sequence. In another experiment, phosphorothioate internucleotide bonds were detected in the bacterial genome as a natural modification. In this study, a polyacrylamide gel electrophoresis (PAGE) autoradiogram analysis of irradiated ds-DNA showed that the oxidation reaction was not inhibited by an isolated guanine. Instead, irrespective of the absence or presence of a phosphorothioate bond, the termination of the ds-DNA oxidation process was predominantly observed on the thymine moieties. Based on the obtained results, it can be concluded that in the discussed case, a hole migration by a hopping mechanism is in competition with an oxidation reaction with a superoxide radical anion. Alternatively, the radical cation migration process is sequence-dependent due to its different ionization potentials. Therefore, the presence of a phosphorothioate internucleotide bond did not change the stability of ds-DNA under UVA irradiation conditions.

9

Dna Damage in Crepis Capillaris Cells in Response to in Vitro Conditions

88%

Nawrocki W. , Siwińska D. , Kwasniewska J. , Maluszynska J.

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10

Assessment of 8-oxo-7,8-dihydro-2′-deoxyguanosine as a marker of oxidative DNA damage in gasoline filling station attendants

88%

Beerappa R. , Venugopal D. , Sen S. , Ambikapathy M. , Rao R. H.

International Journal of Occupational Medicine and Environmental Health

|

2013

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tom 26

|

nr 5

780-789

EN

Objectives: The urinary excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) was used as a biomarker of oxidative DNA damage. The urinary 8-oxodG levels in petrol filling station attendants (exposed) at various petrol bunks were estimated as well as in the unexposed (cashier) population. Materials and Methods: A total of 100 workers (79 petrol fillers and 21 cashiers) aged from 20 to 41 years participated in the study. An informed consent was taken from each participant. Information on personal habits and health was obtained through a questionnaire. After shifts, urine samples were collected analyzed for 8-oxodG using enzyme-linked immunosorbent assay (ELISA). Results: Fifty-three percent of workers were in the 21-30 years age group. The maximum level of 8-oxodG was observed in the age group ≥ 41 years and the minimum in the age group of 31-40 years. The maximum level of 8-oxodG was observed among those workers who had ≥ 21 years of experience. The concentrations of 8-oxodG were significantly higher in petrol fillers than those in cashiers (p < 0.05). Conclusions: Despite the conflicting results obtained in our study it was shown that 8-oxodG is related to chemical exposure. Further research is needed embracing a bigger number of participants to highlight the correlations between the exposure and the effects.

11

Ionisation potential and electron affinity of free 5′,8-cyclopurine-2′-deoxynucleosides. DFT study in gaseous and aqueous phase

88%

Karwowski B.

Open Chemistry

|

2010

|

tom 8

|

nr 1

70-76

EN

Oxidatively generated damage to DNA frequently appears in the human genome as an effect of aerobic metabolism or as the result of exposure to exogenous oxidizing agents. Due to these facts it was decided to present, for the first time, the electron affinity, ionization potential of 5′,8-cyclo-2′-deoxyadenosine/guanosine (cdA, cdG) in their 5′R and 5′S diastereomeric forms. For all points of quantum mechanics studies presented, the density functional theory (DFT) with B3LYP parameters on 6-311++G** basis set level was used. The zero-point vibrational corrected adiabatic electron affinity (AEA) and adiabatic ionization potential (AIP) were calculated. Additionally the vertical electron affinity (VEA), vertical detachment energy (VDE) and vertical ionization potential were taken into consideration. AEA in eV (gaseous/aqueous phase) are as follows: 0.3/1.81 (5′R)cdA, 0.13/1.76 (5′S)cdA, 0.17/1.49 (5′R)cdG, 0.14/1.53 (5′S)cdG and AIP followed the order 7.43/5.59(5′S)cdG, 7.49/5.60(5′R)cdG, 7.77/5.97(5′R)cdA, 7.84/5.93(5′S)cdA. The obtained AIPs were found to be lower than that for corresponding natural nucleosides. Therefore, even though the 5′,8-cyclopurine-2′-deoxynucleoside level in a cell was judged as low, they can play an important role in the stability, replication and transcription of genes. [...]

12

DNA-based biosensors with external Nafion and chitosan membranes for the evaluation of the antioxidant activity of beer, coffee, and tea

88%

Hlavatá L. , Vyskočil V. , Beníková K. , Borbélyová M. , Labuda J.

Open Chemistry

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2014

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tom 12

|

nr 5

604-611

EN

Novel electrochemical DNA-based biosensors with outer-sphere Nafion and chitosan protective membranes were prepared for the evaluation of antioxidant properties of beverages (beer, coffee, and black tea) against prooxidant hydroxyl radicals. A carbon working electrode of a screen-printed three-electrode assembly was modified using a layer-by-layer deposition technique with low molecular weight double-stranded DNA and a Nafion or chitosan film. The membrane-covered DNA biosensors were initially tested with respect to their voltammetric and impedimetric response after the incubation of the beverage and the medium exchange for the solution of the redox indicator [Fe(CN)6]3−/4−. While the Nafion-protected biosensor proved to be suitable for beer and black tea extracts, the chitosan-protected biosensor was successfully used in a coffee extract. Afterwards, the applicability was successfully verified for these biosensors for the detection of a deep degradation of the surface-attached DNA at the incubation in the cleavage agent (hydroxyl radicals generated via Fenton reaction) and for the evaluation of antioxidant properties of coffee and black tea extracts against prooxidant hydroxyl radicals. The investigation of the novel biosensors with a protective membrane represents a significant contribution to the field of electrochemical DNA biosensors utilization.

13

Comparison of the effects of bleomycin and ionizing radiation in two sublines of murine lymphoma L5178Y

88%

Kruszewski M. , Zaim J. , Grądzka I. , Szumiel I.

Nukleonika

|

2001

|

tom Vol. 46, nr 3

81-86

EN

We compared the effects of bleomycin (BLM) and ionizing radiation on two sublines of murine lymphoma L5178Y (LY): LY-R, radiation resistant and LY-S, radiation sensitive. This radiosensitivity difference is related to the ability to rejoin DNA double strand breaks. LY-S cells were about two times more sensitive to BLM than LY-R, similarly as in the case of sensitivity to X rays. Since there was no difference in the P-glycoprotein-related drug transport system between the sublines, it could be expected that the enhanced sensitivity of LY-S cells to BLM was caused by the DNA repair defect. Growth disturbances in BLM treated cell populations were proportional to the lethal effect and their duration was observed until elimination of dead cells (3-6 days after 50 ěM BLM, 1 h at 37oC). There was no slow growth phase accompanied by normal viability, as previously described for X-irradiated LY-S cells. Initial DNA damage, estimated with the single cell gel electrophoresis method was linearly related to BLM dose in LY-S cells; in LY-R cells - in the low dose range (up to 10 ěM) - there was more damage than in LY-S cells, however, at higher doses the dose - effect curves became identical. The doseeffect relationship for ă rays was linear and identical in both cell sublines. DNA damage distribution in BLM treated cells was much less uniform as compared to that in irradiated cells and indicated the presence of cells with severely damaged DNA, a feature typical for BLM action in vitro.

14

Evaluation of biological effects of nanomaterials. Part I. Cyto- and genotoxicity of nanosilver composites applied in textile technologies

88%

Wąsowicz W. , Cieślak M. , Palus J. , Stańczyk M. , Dziubałtowska E. , Stępnik M. , Düchler M.

International Journal of Occupational Medicine and Environmental Health

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2011

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tom 24

|

nr 4

348-358

EN

Objectives: The aim of this study was to investigate the cyto- and genotoxicity of nanocomposites (NCs) and generation of reactive oxygen species (ROS) as a result of particle-cell interactions. Materials and Methods: Titanium dioxide (TiO₂-Ag) and ion-exchange resin (Res-Ag), both coated with silver (Ag), were examined. The murine macrophage J774A.1 cells were incubated in vitro with NC at different concentrations for 24 h. Cytotoxicity was analyzed by the methylthiazolyldiphenyltetrazolium bromide reduction test (MTT reduction test). ROS generation was assessed by incubation of cells with dichlorodihydrofl uorescein diacetate (DCF) and fl ow cytometry. DNA damage was detected by comet assay and included single-strand breaks (SSB), alkali-labile sites (ALS) and oxidative DNA damage after formamidopyrimidine glycosylase (FPG) treatment. The tail moment was used as an indicator of DNA damage. Results: TiO₂-Ag was not cytotoxic up to 200 μg/ml, whereas IC₅₀ for Res-Ag was found to be 23 μg/ml. Intracellular ROS levels were elevated after 4 h of exposure to Res-Ag at the concentration of 50 μg/ml. Both types of NC induced fragmentation of DNA strands, but only one of the composites caused damage to purine bases. TiO₂-Ag induced SSB of DNA at concentrations of 10 and 5 μg/ml. For Res-Ag, a concentration-dependent increase in tail moments was observed. Conclusions: Silver-coated nanocomposites (both TiO₂- Ag and Res-Ag) may cause genotoxic effects in murine macrophages J774A.1. Res-Ag increased generation of ROS which suggested that toxicity of Res-Ag in murine macrophages is likely to be mediated through oxidative stress. This paper will support industry and regulators alike in the assessment of hazards and risks and methods for their mitigation at the earliest possible stage in material and product development.

15

Activation and inhibition of ATM by phytochemicals: awakening and sleeping the guardian angel naturally

88%

Farooqi A. A. , Wu S.-J. , Chang Y.-T. , Tang J.-Y. , Li K.-T. , Ismail M. , Liaw C.-C. , Li R.-N. , Chang H. W.

Archivum Immunologiae et Therapiae Experimentalis

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2015

|

tom 63

|

nr 5

16

An evaluation of post-photodynamic therapy DNA damage in malignant cells using the comet assay

88%

Chwilkowska A. , Saczko J. , Drag-Zalesinska M. , Wysocka T. , Marcinkowska A. , Malarska A. , Banas T.

Cellular and Molecular Biology Letters

|

2002

|

tom 07

|

nr Suppl.

17

DNA damage induced by hydrogen peroxide treatment at 4 st.C and 37 st.C in murine lymphoma L5178Y sublines

88%

Kruszewski M. , Szumiel I.

Acta Biochimica Polonica

|

1994

|

tom 41

|

nr 2

18

Gamma radiation tolerance and protein carbonylation caused by irradiation of resting cysts in the free-living ciliated protist Colpoda cucullus

75%

Saito R. , Koizumi R. , Sakai T. , Shimizu T. , Ono T. , Sogame Y.

Acta Protozoologica

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2020

|

tom 59

|

nr 2

19

Bacterial DNA repair genes and their eukaryotic homologues: 4. The role of nucleotide excision DNA repair (NER) system in mammalian cells

75%

Maddukuri L. , Dudzińska D. , Tudek B.

Acta Biochimica Polonica

|

2007

|

tom 54

|

nr 3

469-482

EN

The eukaryotic cell encounters more than one million various kinds of DNA lesions per day. The nucleotide excision repair (NER) pathway is one of the most important repair mechanisms that removes a wide spectrum of different DNA lesions. NER operates through two sub pathways: global genome repair (GGR) and transcription-coupled repair (TCR). GGR repairs the DNA damage throughout the entire genome and is initiated by the HR23B/XPC complex, while the CSB protein-governed TCR process removes DNA lesions from the actively transcribed strand. The sequence of events and the role of particular NER proteins are currently being extensively discussed. NER proteins also participate in other cellular processes like replication, transcription, chromatin maintenance and protein turnover. Defects in NER underlay severe genetic disorders: xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD).

20

Is concentration and motility of male gametes related to DNA damage measured by comet assay?

75%

Dobrzynska M. M. , Tyrkiel E. J. , Derezinska E. , Ludwicki J. K.

Annals of Agricultural and Environmental Medicine

|

2010

|

tom 17

|

nr 1

73-77