UV-B and heat shock-induced changes in the wild type and UV-B heat shock-tolerant (UV-HSt) strain of the unicellular cyanobacterium Anacystis nidulans
✍ Scribed by R. K. Gour; S. Singh; P. K. Pandey; Prof. P. S. Bisen
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 589 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0233-111X
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✦ Synopsis
Ultraviolet-B and heat shock (HS)') induced changes in growth kinetics, NO; reductase (NR), glutamine synthetase (GS), NO; uptake and NO; efflux activities, have been studied in the wild type Anacystis nidulans and its UV-HS' strain. The application of UV-B and HS stresses either used separately or in combination shows a drastic changes in growth rates of wild type, and insignificant effect on the growth of the UV-HS' strain. The wild type cells, in contrast to its UV-HS' strain exhibits insignificant effect on NR and GS activities upon UV-B radiation followed by heat shock treatment. Similar treatments to the wild type cells resulted in maximum reduction of NR and GS activities. The NO; uptake and NO; efflux activities are found to be lower in the UV-HS' strain than in the wild type counterpart and both the systems consisted of an initial rapid phase followed by a slower one. NH: grown cells when transferred to NO; medium in presence of streptomycin showed significant inhibition in the development of both the NO; uptake and NO; efflux systems indicating that de novo protein synthesis is required for the development of NO; uptake and NO; efflux systems. Whereas the same cells in the presence of L-methionhe-DL-sulfoximine (MSX) showed marginally higher NO; uptake but, exhibits only 42% NO; efflux to that of MSX-devoid both the cells. It is suggested that NH; assimilation via GS is necessarily required for NO; efflux system to be functional.