UV and cold tolerance of a pigment-producing Antarctic Janthinobacterium sp. Ant5-2

• Published in: Extremophiles
• Main Authors: Mojib, Nazia, Farhoomand, Amin, Andersen, Dale T., Bej, Asim K.
• Other Authors: Red Sea Research Center (RSRC), Marine Science Program, Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., CH464, Birmingham, 35294-1170 AL, United States, Carl Sagan Center for the Study of Life in the Universe, SETI Institute, 189 Bernardo Ave., Suite 100, Mountain View, CA, 94043, United States
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Nature 2013
• Subjects: 2(5H)-furanone; ALI assay; D37 value; EPS; Freeze-thaw; Purple violet pigment (PVP); vioA; Antarc*; Antarctic
• Online Access: http://hdl.handle.net/10754/562687; https://doi.org/10.1007/s00792-013-0525-9

In this paper, we describe the UV and cold tolerance of a purple violet pigment (PVP)-producing Antarctic bacterium, Janthinobacterium sp. Ant5-2 (PVP+) and compared its physiological adaptations with a pigmentless mutant strain (PVP-). A spontaneous deletion of vioA that codes for tryptophan monooxygenase, the first gene involved in the biosynthesis of PVP was found in PVP- strain. The PVP- culture exhibited significantly reduced survival during exponential and stationary growth phase following exposure to UVB (320 nm) and UVC (254 nm) (dose range: 0-300 J/m2) when compared to wild-type (PVP+) cultures. In addition, upon biochemical inhibition of pigment synthesis by 2(5H)-furanone, wild-type PVP+ cultures exhibited approximately 50-fold growth reduction at a higher dose (300 J/m2) of UV. Increased resistance to UV was observed upon inducing starvation state in both PVP+ and PVP- cultures. There was 80 % (SD = ±8) reduction in extrapolymeric substance (EPS) production in the PVP- cultures along with a compromised survival to freeze-thaw cycles when compared to the PVP+ cultures. Perhaps synthesis of PVP and EPS are among the key adaptive features that define the survival of this bacterium in Antarctic extreme conditions, especially during austral summer months. © 2013 Springer Japan.