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EFFECTS OF ULTRAVIOLET RADIATION ON THE MODERATE HALOPHILE HALOMONAS ELONGATA AND THE EXTREME HALOPHILE HALOBACTERIUM SALINARUM
Citation:
Martin, E. L., L. L. Reinhardt, L. L. Baum, M. R. Becker, Shaffer, AND T. A. Kokjohn. EFFECTS OF ULTRAVIOLET RADIATION ON THE MODERATE HALOPHILE HALOMONAS ELONGATA AND THE EXTREME HALOPHILE HALOBACTERIUM SALINARUM. CANADIAN JOURNAL OF MICROBIOLOGY 46(2):180-187, (2000).
Description:
Both the moderately halophilic bacterium, Halomonas elongata, and the extremely halophilic archaea, Halobacterium salinarum, can be found in hypersaline environments (e.g., salterns). On complex media, H. elongata grows over a salt range of 0.05-5.2 M, whereas, H. salinarum multiplies over a salt range of 2.5-5.2 M. The purpose of this study was to illustrate the effect that solar (UV-A and UV-B) and germicidal radiation (UV-C) had on the growth patterns of these bacteria at varied salt concentrations. Halomonas elongata grown on a complex medium at 0.05, 1.37, and 4.3 M NaCl, was found to be more sensitive to UV-A and UV-B radiation, as the salt concentration of the medium increased. Halobacterium salinarum grown on a complex
medium at 3.0 and 4.3 M NaCl did not show a significant drop in viability after 39.3 kJ.m-2 of UV-A and UV-B exposure. When exposed to UV-C, H. elongata exhibited substantially more sensitivity than H. salinarum. In H. elongata, differential sensitivity to UV-C was observed. At 0.05 M NaCl, H. elongata was less sensitive to UV-C than at 1.37 and 4.3 M NaCl. Both bacteria showed some photoreactivation when incubated under visible light following both UV-A, UV-B, and UV-C exposure. Mutagenesis following UV-C exposure was demonstrated
by both organisms.