Temat: comet assay - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: In vitro evaluation of zearalenone toxicity by comet assay
Autorzy:: Harcarova, M.
Conkova, E.
Kolenicova, S.
Holeckova, B.
Proskovcova, M.
Tematy:: mycotoxins
toxicity
comet assay; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/16539336.pdf Link otwiera się w nowym oknie
Opis:: The aim of this study was to reveal the potentially genotoxic effect of zearalenone on bovine lymphocytes by comet assay in vitro. The bovine lymphocytes were exposed to various zearalenone concetrations (50; 10; 2; 0.4 and 0.08 ppm). The viability and DNA damage of lymphocytes was monitored after 2 h, 24 h, 48 h and 72 h. After 2 hours of zearalenone exposure, statistically significant DNA damage occurred at all tested concentrations of 0.08 ppm (12.2±1.25; p<0.05), 0.4 ppm (12.7±0.88; p<0.01), 2 ppm (12.0±0.51; p<0.01), 10 ppm (11.2±0.47; p<0.01) and at 50 ppm (14.2±0 61; p<0.001). Significantly greater DNA damage was also found after 24 h, 48 h and 72 h. The obtained results showed that zearalenone may induce DNA damage of the bovine lymphocytes.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Detection of alkylation damage in human lymphocyte DNA with the comet assay.
Autorzy:: Collins, Andrew
Dušinská, Mária
Horská, Alexandra
Tematy:: AlkA
DNA damage
comet assay; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1044089.pdf Link otwiera się w nowym oknie
Opis:: 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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Labile iron pool correlates with iron content in the nucleus and the formation of oxidative DNA damage in mouse lymphoma L5178Y cell lines.
Autorzy:: Kruszewski, Marcin
Iwaneńko, Teresa
Tematy:: iron homeostasis
hydrogen peroxide
comet assay; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1043668.pdf Link otwiera się w nowym oknie
Opis:: Labile iron pool (LIP) constitutes a crossroad of metabolic pathways of iron-containing compounds and is midway between the cellular need for iron, its uptake and storage. In this study we investigated oxidative DNA damage in relation to the labile iron pool in a pair of mouse lymphoma L5178Y (LY) sublines (LY-R and LY-S) differing in sensitivity to hydrogen peroxide. The LY-R cells, which are hydrogen peroxide-sensitive, contain 3 times more labile iron than the hydrogen peroxide-resistant LY-S cells. Using the comet assay, we compared total DNA breakage in the studied cell lines treated with hydrogen peroxide (25 μM for 30 min at 4°C). More DNA damage was found in LY-R cells than in LY-S cells. We also compared the levels of DNA lesions sensitive to specific DNA repair enzymes in both cell lines treated with H2O2. The levels of endonuclease III-sensitive sites and Fapy-DNA glycosylase-sensitive sites were found to be higher in LY-R cells than in LY-S cells. Our data suggest that the sensitivity of LY-R cells to H2O2 is partially caused by the higher yield of oxidative DNA damage, as compared to that in LY-S cells. The critical factor appears to be the availability of transition metal ions that take part in the OH radical-generating Fenton reaction (very likely in the form of LIP).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Genotoxic effects of 60Co gamma-rays on Chinese hamster ovary (CHO) cells
Autorzy:: Dicu, T.
Brie, I.
Virag, P.
Fischer, E.
Perde, M.
Foriş, V.
Cernea, V.
Cosma, C.
Tematy:: cellular radiosensitivity
genotoxic effects
ionizing radiation
comet assay; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/147740.pdf Link otwiera się w nowym oknie
Opis:: The aim of the present study was to evaluate the cellular radiosensitivity and radiation-induced DNA damage and repair in Chinese hamster ovary (CHO) cells. Cell survival after irradiation was assessed using the clonogenic assay. The initial, radio-induced and residual DNA damage in Chinese hamster ovary (CHO) cells exposed to 60Co gamma-rays were determined using the alkaline comet assay. A linear-quadratic (LQ) survival curve was observed in CHO line. Data obtained by comet assay demonstrated a linear dose-response correlation in the range of tested doses (0.3-4 Gy). The process of DNA repair was modeled by exponential equation. In addition, we found a good correlation (R2 = 0.995) between clonogenic cell survival and radio-induced DNA damage.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The effect of quercetin on oxidative DNA damage and myelosuppression induced by etoposide in bone marrow cells of rats
Autorzy:: Papież, Monika
Tematy:: quercetin
etoposide
myelosuppression
oxidative DNA damage
comet assay; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1039316.pdf Link otwiera się w nowym oknie
Opis:: There is increasing evidence for the existence of an association between the presence of etoposide phenoxyl radicals and the development of treatment-related acute myeloid leukemia (t-AML), which occurs in a few percent of patients treated with this chemotherapeutic agent. The most common side effect caused by etoposide is myelosuppression, which limits the use of this effective drug. The goal of the study was to investigate the influence of antioxidant querectin on myelosuppression and oxidative DNA damage caused by etoposide. The influence of quercetin and/or etoposide on oxidative DNA damage was investigated in LT-12 cell line and bone marrow cells of rats via comet assay. The effect of quercetin on myelosuppression induced by etoposide was invetsigated by cytological analysis of bone marrow smears stained with May-Grünwald-Giemsa stain. Etoposide caused a significant increase in oxidative DNA damage in bone marrow cells and LT-12 cell line in comparison to the appropriate controls. Quercetin significantly reduced the oxidative DNA damage caused by etoposide both in vitro and in vivo. Quercetin also significantly protected against a decrease in the percentage of myeloid precursors and erythroid nucleated cells caused by etoposide administration in comparison to the group treated with etoposide alone. The results of the study indicate that quercetin could be considered a protectively acting compound in bone marrow cells during etoposide therapy.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The changes of antioxidant defense system caused by quercetin administration do not lead to DNA damage and apoptosis in the spleen and bone marrow cells of rats
Autorzy:: Taha, Hevidar
Cierniak, Agnieszka
Papież, Monika
Krzyściak, Wirginia
Józkowicz, Alicja
Bzowska, Małgorzata
Piskula, M.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 7.

Tytuł:: The changes of antioxidant defense system caused by quercetin administration do not lead to DNA damage and apoptosis in the spleen and bone marrow cells of rats
Autorzy:: Bzowska, Małgorzata
Krzyściak, Wirginia
Papież, Monika
Cierniak, Agnieszka
Józkowicz, Alicja
Taha, Hevidar
Piskula, M.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: Modified neutral comet assay for human lymphocytes
Autorzy:: Wojewódzka, M.
Grądzka, I.
Buraczewska, I.
Tematy:: DNA double strand breaks
human lymphocyte
neutral comet assay; Pokaż więcej
Wydawca:: Instytut Chemii i Techniki Jądrowej
Powiązania:: https://bibliotekanauki.pl/articles/147130.pdf Link otwiera się w nowym oknie
Opis:: Comet assay under neutral conditions allows the detection of DNA double-strand breaks, considered to be the biologically relevant radiation-induced lesion. In this report we describe modifications of the neutral comet method, which simplify and facilitate its use for estimation of DNA double strand breaks in human lymphocytes irradiated with doses of 60Co gamma-rays (from 10 to 100 Gy). The analysis carried out according to this protocol takes less time than those published so far. Also, the use of lysis at 50°C is avoided; this is important in view of the presence of heat-labile sites in the DNA of irradiated cells, recently reported by Rydberg [12]. The comets have well defined, sharp limits, are suitable for computer image analysis and chromatin of the control cells remains condensed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Responsiveness of Lycopersicon pimpinellifolium to acute UV-C exposure: histo-cytochemistry of the injury and DNA damage
Autorzy:: Iriti, M
Guarnieri, S
Faoro, F
Tematy:: UV-C
protoplasts
comet assay
currant tomato
oxidative stress; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1041072.pdf Link otwiera się w nowym oknie
Opis:: The in vivo and in vitro effects of UV-C (254 nm) exposure (0.039 watt · m-2 · s for 2 h) of currant tomato (Lycopersicon pimpinellifolium), indigenous to Peru and Ecuador, were assayed. H2O2 deposits, dead cells and DNA damage were localized, 12/24 h after irradiation, mainly in periveinal parenchyma of the 1st and 2nd order veins of the leaves, and before the appearance of visible symptoms, which occurred 48 h after irradiation. Cell death index was of 43.5 ± 12% in exposed leaf tissues, 24 h after treatment. In currant tomato protoplasts, the percentage of viable cells dropped 1 h after UV-C irradiation from 97.42 ± 2.1% to 43.38 ± 4.2%. Afterwards, the protoplast viability progressively decreased to 40.16 ± 7.25% at 2 h, to 38.31 ± 6.9% at 4 h, and to 36.46 ± 1.84% at 6 h after the exposure. The genotoxic impact of UV-C radiation on protoplasts was assessed with single cell gel electrophoresis (SCGE, or comet assay). UV-C treatment greatly enhanced DNA migration, with 75.37 ± 3.7% of DNA in the tail versus 7.88 ± 5.5% in the case of untreated nuclei. Oxidative stress by H2O2 used as a positive control, induced a similar damage on non-irradiated protoplasts, with 71.59 ± 5.5% of DNA in the tail, whereas oxidative stress imposed on UV-C irradiated protoplasts slightly increased the DNA damage (85.13 ± 4.1%). According to these results, SCGE of protoplasts could be an alternative to nuclei extraction directly from leaf tissues.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Tenocyclidine treatment in soman-poisoned rats - intriguing results on genotoxicity versus protection
Autorzy:: Petek, Maja
Berend, Suzana
Kopjar, Nevenka
Želježić, Davor
Mladinić, Marin
Radić, Božica
Vrdoljak, Ana
Tematy:: rat
tenocyclidine
soman
cholinesterase activity
brain
genotoxicity
comet assay
plasma; Pokaż więcej
Wydawca:: Polskie Towarzystwo Biochemiczne
Powiązania:: https://bibliotekanauki.pl/articles/1040822.pdf Link otwiera się w nowym oknie
Opis:: This study aimed to evaluate the antidotal potency of tenocyclidine (TCP) that probably might protect acetylcholinesterase (AChE) in the case of organophosphate poisoning. TCP was tested alone as a pretreatment or in combination with atropine as a therapy in rats poisoned with ¼ and ½ of LD50 of soman. Possible genotoxic effects of TCP in white blood cells and brain tissue were also studied. Results were compared with previous findings on the adamantyl tenocyclidine derivative TAMORF. TCP given alone as pretreatment, 5 min before soman, seems to be superior in the protection of cholinesterase (ChE) catalytic activity in the plasma than in brain, especially after administration of the lower dose of soman. Plasma activities of the enzyme after a joint treatment with TCP and soman were significantly increased at 30 min (P < 0.001) and 24 h (P = 0.0043), as compared to soman alone. TCP and atropine, given as therapy, were more effective than TCP administered alone as a pretreatment. The above therapy significantly increased activities of the enzyme at 30 min (P = 0.046) and 24 h (P < 0.001), as compared to controls treated with ¼ LD50 of soman alone. Using the alkaline comet assay, acceptable genotoxicity of TCP was observed. However, the controversial role of TCP in brain protection of soman-poisoned rats should be studied further.
Dostawca treści:: Biblioteka Nauki

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