RT Journal Article
SR Electronic
T1 Bistablity in Fluorescence from a purple non-sulfur bacteria
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 132498
DO 10.1101/132498
A1 Anirban Bose
A1 Sufi O Raja
A1 Sanhita Ray
A1 Anjan Kr Dasgupta
YR 2017
UL http://biorxiv.org/content/early/2017/06/05/132498.abstract
AB Bistable optical emission has been observed for photosynthetic purple non-sulfur bacteria Rhodobacter capsulatus SB1003. The microbes respond to UV excitation (at 395nm) in a bifurcating way one branch corresponding to increase and the other corresponding to diminishing fluorescent emission in the range 590-685nm.The switching between such bifurcating branches can be observed when parameters like concentration, temperature are varied or static magnetic field is applied. Thus switching from amplification to reduction occurs if fluorophore concentration lowered. Again if temperature is lowered a steady quenching (instead of amplification) of fluorescence is observed. However presence of magnetic field of the order of 0.5 T reverts this and once again the systems resumes its fluoresence amplifying state. We propose that aggregation of bacterial porphyrin and regulation of such aggregation by photon excitation may explain this bistablity. Possible ecological implication of the photosynthetic bistability is suggested.