Evidence for repair of ultraviolet-induced damage in Cystobacter species (Myxobacterales)

✍ Scribed by Dr. K. Grimm

• Book ID: 102386804
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 438 KB
• Volume: 18
• Category: Article
• ISSN: 0233-111X
• DOI: 10.1002/jobm.19780180603

✦ Synopsis

Abstract

Cystobacter species strain CK 1 does not grow with more than 0.2 μg/ml acriflavine. Spontaneous two‐step mutants growing with 2 μg acriflavine per ml have been selected. One mutant (strain CK 3) was used to investigate the effect of repair inhibitors. Both strains exhibit pronounced shoulders in their UV dose curves of inactivation. Acriflavine (AF), coumarin (CU), and caffeine (CA) when incorporated in the post‐irradiation plating medium decreased survival of irradiated cells. Post‐treatment with 2 μg acriflavine/ml abolished the shoulder of the curve. Caffeine (1600 μg/ml) and coumarin (350 μg/ml) reduced it only to about 40%. It is concluded that probably two repair mechanisms are present.

Pre‐treatment of the cells with 2 μg acriflavine/ml for two hours before UV‐irradiation resulted in a constant dose enhancement factor of 1.9. The protective effect is increased with the time of treatment with acriflavine. This may indicate that pyrimidine dimers are responsible for UV‐inactivation.