Genome‐wide Examination of the Natural Solar Radiation Response in Shewanella oneidensis MR‐1

Abstract

We previously reported that Shewanella oneidensis MR-1 is extremely sensitive to natural solar radiation (NSR). Here we analyzed the global transcriptional profile of MR-1 during a 1-h recovering period after exposure to ambient solar light at a dose that yields about 20% survival rate on a Luria-Bertani (LB) plate. We observed the induction of DNA damage-repair genes, the SOS response as well as detoxification strategies that we previously observed in MR-1 following artificial UV-A irradiation. Few prophage-related genes were induced by natural solar UV radiation, however, in contrast to what was observed following artificial UV-B irradiation. Overall, the cellular response to NSR in MR-1 was more similar to that of UV-A than that of UV-B, but additional genes involved in detoxification were induced compared with induction by either UV-B or UV-A or their sum. Thus, oxidative stress appeared to contribute greatly to the NSR-induced cytotoxic effects in MR-1. A total of 29.1% of genome showed differential expression following NSR exposure, which is much greater than following exposure by UV-B (4.0%), UV-A (8.2%) or their sum (10.7%). Our data suggest that NSR may impact biological processes in a much more complex manner than previously thought.

The Global Response of Nostoc punctiforme ATCC 29133 to UVA Stress, Assessed in a Temporal DNA Microarray Study

“…Another energy response to UVA that was found in our study was the down‐regulation of some of the genes associated with the a and b subunits of ATP synthase (Npun_F4858, Npun_F4860, Npun_F4861). Similar responses in ATP synthase‐associated genes have been documented in Shewanella oneidensis MR‐1 following exposure to natural solar radiation , possibly as a transient inhibition to energy production.…”

Changes of cell growth and magnetosome biomineralization in Magnetospirillum magneticum AMB-1 after ultraviolet-B irradiation

“…Both base/nucleotide excision repair and recombinational repair pathway participated in UV induced damage repair. Genes that were involved in scavenging oxygen radicals were also noticed up regulated after UV irradiation (Reid and Isaksen, 1976; Huang et al, 2002; Qiu et al, 2005a,b; Yuan et al, 2012). …”

“…This suggestion is also supported by previous reports that UV radiation can strongly affect the metabolism of other microorganisms. For example, up regulated nitrate reduction genes such as nap and nos genes and genes related to iron-sequestering ( bpc and hem H) and peroxide metabolism (e.g., oxy R, kat G, and sod B) were verified through transcriptome analyses of both radio-resistant bacterium Deinococcus species and a facultative anaerobic Gammaproteobacteria Shewanella oneidensis MR-1 after UV irradiation (Qiu et al, 2005a,b). Nevertheless, further investigations on time-series culture medium composition analyses and transcriptome of the irradiated AMB-1 cells are needed to reveal the mechanisms of these phenomena.…”

Enhancement of UV Light Sensitivity of a Vibrio parahaemolyticus O3:K6 Pandemic Strain Due to Natural Lysogenization by a Telomeric Phage

“…The presence of the 42-kb prophage has a notable effect on the sensitivity of the pandemic strain to UV irradiation, including solar UV irradiation, due to prophage induction and cell lysis. This phenomenon is not unprecedented as prophage activation is the major lethal factor in the highly UV-sensitive Shewanella oneidensis MR1 (31). Death of lysogenic cells by temperate phage induction is one mode of bacterial death due to infection by bacteriophages (16,36) and a substantial cause of marine bacterial mortality (34).…”