Repair,replication and survival in UV-irradiatedEscherichia coli |
| |
Authors: | M Sedliaková V Slezáriková |
| |
Institution: | (1) Department of Molecular Genetics, Cancer Research Institute, Slovak Academy of Sciences, 880 32 Bratislava |
| |
Abstract: | The influence of dimer removal through excision or photoreactivation on the kinetics of DNA synthesis, sedimentation profiles
of DNA molecules and survival of cells was investigated in excision-deficient and excision-proficientEscherichia coli K-12 after a flux of 20 J m−2. In excision-deficient cells photoreactivation did not influence the kinetics of DNA synthesis for a long period and the
sedimentation properties of DNA synthesized immediately after photoreactivation were influenced only slightly. However, survival
was increased remarkably. In excision-proficient cells where dimers were removed through excision, the kinetics of DNA synthesis
increased rapidly, normal-sized DNA molecules were synthesized 60 min after irradiation and survival was substantially higher
than in the above-mentioned case. This can hardly be interpreted as a more complete repair of dimers by excision because the
persistence of dimers in these cells did not significantly influence either the kinetics of DNA synthesis or normalization
of DNA molecules and/or survival of cells. It is concluded that persisting dimers play an important role in excision-deficient
but not in excision-proficient cells, that a non-dimer damage to DNA causes inhibition of DNA synthesis after UV and that
this damage ia of primary importance for excision-proficient cells which can easily cope with persisting dimers. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|