This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Macaluso, A. L.
Right arrow Articles by Sanders, R. W.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Macaluso, A. L.
Right arrow Articles by Sanders, R. W.
Agricola
Right arrow Articles by Macaluso, A. L.
Right arrow Articles by Sanders, R. W.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, July 2009, p. 4525-4530, Vol. 75, No. 13
0099-2240/09/$08.00+0     doi:10.1128/AEM.02803-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Direct Effects of UV-B Radiation on the Freshwater Heterotrophic Nanoflagellate Paraphysomonas sp.{triangledown}

Amy L. Macaluso,1 David L. Mitchell,2 and Robert W. Sanders1*

Department of Biology, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122,1 University of Texas M. D. Anderson Cancer Center, Science Park/Research Division, Smithville, Texas 789572

Received 10 December 2008/ Accepted 30 April 2009

The formation of DNA photoproducts in organisms exposed to ambient levels of UV-B radiation can lead to death and/or reduced population growth in aquatic systems. Dependence on photoenzymatic repair to reverse DNA damage caused by UV-B radiation is demonstrated for Paraphysomonas sp., a member of a widely distributed genus of heterotrophic nanoflagellates. At 20°C, Paraphysomonas sp. was exposed to a range of UV-B intensities encountered in natural systems. Populations of the flagellate survived and grew in a dose-dependent manner, but only when simultaneously exposed to photorepair radiation (PRR). In contrast, flagellates exposed to UV-B at 15°C suffered 100% mortality except at the lowest UV-B level (with PRR) tested, which suggested a photorepair temperature optimum above 15°C. After acute UV-B exposures, DNA damage (measured as the formation of pyrimidine dimers) was reduced only in organisms that underwent subsequent exposure to PRR. Populations kept in the dark after UV-B exposure maintained the initial levels of pyrimidine dimers. These results are the first to demonstrate the reliance of a heterotrophic flagellate on photoenzymatic DNA repair for survival from UV-B exposure.

* Corresponding author. Mailing address: Department of Biology, Temple University, 1900 North 12th St., Philadelphia, PA 19122. Phone: (215) 204-2056. Fax: (215) 204-6646. E-mail: robert.sanders{at}temple.edu

{triangledown} Published ahead of print on 8 May 2009.

Applied and Environmental Microbiology, July 2009, p. 4525-4530, Vol. 75, No. 13
0099-2240/09/$08.00+0     doi:10.1128/AEM.02803-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»