Adenosine Diphosphate Ribosylation of Dinitrogenase Reductase and Adenylylation of Glutamine Synthetase Control Ammonia Excretion in Ethylenediamine-Resistant Mutants of Azospirillum brasilense Sp7 |
| |
Authors: | A Srivastava A K Tripathi |
| |
Institution: | (1) Health Sciences Research Center, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, 52900, Israel |
| |
Abstract: | Three bacterial strains—Escherichia coli, Acinetobacter calcoaceticus, and the A. calcoaceticus RecA(−) mutant—underwent photosensitization by a low-concentration (0.73 μmol/L) tetramethyl pyridyl porphine (a cationic
hydrophylic photosensitizer) and a 4-J/cm2 dose of 407 to 420 nm blue light. The viability of the first two strains decreased by approximately 60%. and that of the
RecA(−) strain decreased by 90%. Increasing the amount of photosensitizer to 14.6 μmol/L at the same dose of blue light resulted
in a 95% to 98% decrease in viability of the three strains. Very little damage to the bacterial DNA was observed after this
treatment. Increasing the concentration photosensitizer under the same illumination conditions also resulted in very little
damage to the DNA. Western blotting demonstrated that the low photosensitization procedures enhance RecA production for mending
the damaged chromosomal DNA. RecA production as a result of low-dose photosensitization was confirmed and demonstrated by
immunofluorescent staining and gold immunolabeling. Although DNA is not the primary target for photosensitization, this process
of RecA production may provide a certain degree of DNA mending and may also affect the survival of bacterial cells on low-intensity
photosensitization. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|