Unprogrammierte DNA-Synthese (DNA-Reparatur) in Milz-und Thymuszellen der Ratte nach Einwirkung von UV-Licht, Röntgenstrahlen oder Methylmethansulfonat in vitro / Unscheduled DNA Synthesis (DNA-Repair) within Splenic and Thymic Cells of the Rat under the Influence of UV-Light, X-Irradiation and/or Methyl-methanesulfonate

1980 ◽  
Vol 35 (1-2) ◽  
pp. 106-111 ◽  
Author(s):  
K. Tempel
Keyword(s):  
Dna Repair ◽  
Dna Synthesis ◽  
Excision Repair ◽  
Uv Light ◽  
Methyl Methanesulfonate ◽  
X Rays ◽  
Unscheduled Dna Synthesis ◽  
Splenic Cells ◽  
X Irradiation

Abstract DNA -Repair, Splenocytes, Thymocytes, Irradiation, Methyl-M ethanesulfonate Unscheduled DNA synthesis (UDS) of splenic and thymic cells of the rat has been stimulated in vitro by UV-light (8-128 J × m-2), X-rays (120-3480 rd), methyl-methanesulfonate (MMS), and/or a combination of UV-light and X -irradiation. The height of U DS-induced stim ulation of incorporation of [3H] thymidine into splenic and thymic cell DNA at saturation doses of UV-light (splenic cells: 8, thymic cells: 96 J × m-2) or X -irradiation (splenic cells: 960, thymic cells:~3480 rd) suggest that the greater sensitivity of T-cells (represented by thymic cells) towards UV-light and the greater sensitivity of B-cells (represented by splenic cells) towards X-rays can be explained - at least partly - in terms of less efficient excision repair systems.

scholarly journals An alternative eukaryotic DNA excision repair pathway.

1995 ◽  
Vol 15 (8) ◽  
pp. 4572-4577 ◽  
Author(s):  
G A Freyer ◽  
S Davey ◽  
J V Ferrer ◽  
A M Martin ◽  
D Beach ◽  
...  
Keyword(s):  
Dna Repair ◽  
Excision Repair ◽  
Uv Light ◽  
Repair Process ◽  
Dna Lesions ◽  
Repair Pathway ◽  
Cyclobutane Pyrimidine Dimers ◽  
Dna Excision Repair ◽  
Pyrimidine Dimers

DNA lesions induced by UV light, cyclobutane pyrimidine dimers, and (6-4)pyrimidine pyrimidones are known to be repaired by the process of nucleotide excision repair (NER). However, in the fission yeast Schizosaccharomyces pombe, studies have demonstrated that at least two mechanisms for excising UV photo-products exist; NER and a second, previously unidentified process. Recently we reported that S. pombe contains a DNA endonuclease, SPDE, which recognizes and cleaves at a position immediately adjacent to cyclobutane pyrimidine dimers and (6-4)pyrimidine pyrimidones. Here we report that the UV-sensitive S. pombe rad12-502 mutant lacks SPDE activity. In addition, extracts prepared from the rad12-502 mutant are deficient in DNA excision repair, as demonstrated in an in vitro excision repair assay. DNA repair activity was restored to wild-type levels in extracts prepared from rad12-502 cells by the addition of partially purified SPDE to in vitro repair reaction mixtures. When the rad12-502 mutant was crossed with the NER rad13-A mutant, the resulting double mutant was much more sensitive to UV radiation than either single mutant, demonstrating that the rad12 gene product functions in a DNA repair pathway distinct from NER. These data directly link SPDE to this alternative excision repair process. We propose that the SPDE-dependent DNA repair pathway is the second DNA excision repair process present in S. pombe.

Bleomycin - Induced DNA Damage and DNA Repair in Chicken Embryo Cells as Compared to X-Irradiation

1999 ◽  
Vol 54 (12) ◽  
pp. 1068-1074 ◽  
Author(s):  
Karlheinz Tempel ◽  
Hannelore Kortenbeutel ◽  
Christina von Zallinger
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Synthesis ◽  
Chicken Embryo ◽  
Test System ◽  
Cytotoxic Agents ◽  
X Rays ◽  
In Ovo ◽  
Embryo Cells

Following in vitro- and in ovo-exposure of chicken embryo cells, the level of bleomycin (BM) - induced damage was evaluated by using DNA synthesis, nucleoid sedimentation (SED), and viscometry of alkaline cell lysates (VISC). This damage was compared to Xirradiation, using 5.9-378 nM BM in vitro, 1.5-116 μg BM/egg in ovo, and 2-32 Gy, respectively, in vitro as well as in ovo. With respect to BM. the most notable result is the increase in DNA synthesis and VISC at the lowest concentrations of the drug. A decrease in both parameters was observed at high BM concentrations and following exposure to X-rays, concomitantly with an increase in SED. Regarding the radiomimetic drug BM and X-rays, different modes of DNA damage and DNA repair are suggested by previous investigations and the present results. Therefore, further evidence is presented, that the chicken embryo can act as a simple, rapid and inexpensive test system to characterize the biological effects of many nucleo- and/or cytotoxic agents.

An in vitro and an in vivo unscheduled DNA synthesis assay with a zinc oxide/ hexachloroethane (Zn/HCE) smoke

1996 ◽  
Vol 15 (1) ◽  
pp. 38-44 ◽  
Author(s):  
D. Andersonl ◽  
SD Blowers ◽  
TC Marrs ◽  
P. Rice
Keyword(s):  
Dna Repair ◽  
Dna Synthesis ◽  
Health Hazard ◽  
Micronucleus Assay ◽  
Zinc Content ◽  
Rat Hepatocytes ◽  
Unscheduled Dna Synthesis ◽  
In Vitro Investigation

1 Since Zn/HCE smoke has been shown previously to be weakly positive in the Ames test, and negative in the bone marrow micronucleus assay, other assays including a second in vivo assay examining unscheduled DNA synthesis (UDS) in rat hepatocytes has been carried out, as recommended by the UK Department of Health guide lines. 2 Zn/HCE smoke was assessed for its ability to induce DNA repair in an UDS assay both in vitro in cultured rat hepatocytes and in rat hepatocytes after in vivo treatment by inhalation. 3 For the in vitro investigation, two studies were carried out assessing media exposed to Zn/HCE smoke using at least seven concentrations up to a toxic level. At the highest concentration of Zn/HCE smoke, where some viable cells were seen, an increase in UDS was observed in both experiments. However this was not statistcally significant, was only seen at a level where toxicity was observed and was therefore considered not to be biologically significant. 4 In the in vivo investigation, one study was carried out in three separate parts, assessing two doses of Zn/HCE smoke characterised by their zinc content as approxi mately 20 and 56 μg l -1 air. A dose-related increase in UDS was observed which was not statistically sig nificant. The positive control behaved as anticipated, showing a highly statistically significant response. 5 It was concluded that Zn/HCE smoke did not induce unscheduled DNA repair in the in vitro or in vivo UDS assays under the conditions used in the studies. The overall lack of genotoxic effect of this smoke in this and previous studies in this laboratory would not suggest a major health hazard.

Sign in / Sign up

Export Citation Format

Share Document