PT  - JOURNAL ARTICLE
AU  - Anirban Bose
AU  - Sufi O Raja
AU  - Sanhita Ray
AU  - Anjan Kr Dasgupta
TI  - Bistablity in Fluorescence from a purple non-sulfur bacteria
AID  - 10.1101/132498
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 132498
4099  - http://biorxiv.org/content/early/2017/06/04/132498.short
4100  - http://biorxiv.org/content/early/2017/06/04/132498.full
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 two different manners, one in which fluorescence emission in the range 590-685nm is amplified with respect to time, and the other state corresponds to diminishing fluoresence. This switching can be observed at room temperature 298K when fluorophore (or bacterial) concentration is gradually increased. If temperature is lowered a steady quenching of fluorescence is observed. However presence of a weak magnetic field of the order of (less than 0.5 T) is introduced. We propose that aggregation of bacterial porphyrin induced by photon excitation may lead to such bistablity. Possibility of photon driven cellular communication through such porphyrin aggregation is suggested.