ORIGINAL RESEARCH ARTICLE published: 06 December 2013 doi: 10.3389/fmicb.2013.00374 Rhythmic and sustained oscillations in metabolism and gene expression of Cyanothece sp. ATCC 51142 under constant light Sandeep B. Gaudana1†‡, S. Krishnakumar1‡, Swathi Alagesan1, Madhuri G. Digmurti 1, Ganesh A. Viswanathan1, Madhu Chetty 2 and Pramod P.Wangikar1* 1 Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India 2 Gippsland School of Information Technology, Monash University, VIC, Australia Edited by: Cyanobacteria, a group of photosynthetic prokaryotes, oscillate between day and night time Thomas E. Hanson, University of metabolisms with concomitant oscillations in gene expression in response to light/dark Delaware, USA cycles (LD).The oscillations in gene expression have been shown to sustain in constant light Reviewed by: (LL) with a free running period of 24 h in a model cyanobacterium Synechococcus elongatus Kathleen Scott, University of South Florida, USA PCC 7942. However, equivalent oscillations in metabolism are not reported under LL in Ivan Berg, Albert-Ludwigs-Universität this non-nitrogen fixing cyanobacterium. Here we focus on Cyanothece sp. ATCC 51142, a Freiburg, Germany unicellular, nitrogen-fixing cyanobacterium known to temporally separate the processes *Correspondence: of oxygenic photosynthesis and oxygen-sensitive nitrogen fixation. In a recent report, Pramod P.Wangikar, Department of metabolism of Cyanothece 51142 has been shown to oscillate between photosynthetic Chemical Engineering, Indian Institute of Technology Bombay, Powai, and respiratory phases under LL with free running periods that are temperature dependent Mumbai 400076, India but significantly shorter than the circadian period. Further, the oscillations shift to circadian e-mail:
[email protected] pattern at moderate cell densities that are concomitant with slower growth rates.