Genus vibrio - blue influroscence

 

     Luminous bacteria occur ubiquitously in marine environments isolated from seawater, sediment, detritus, and light-emitting organs of marine animals.Now, 23 species of luminous marine bacteria have beeni dentified,  including 11 Vibrio species, four Aliivibrios species, six Photobacterium species, and two Shewanellas species. Luminous bacteria use bacterial luciferase to produce a bluish-green light. The luciferase (class of oxidative enzymes which produce bioluminescence) catalyses the oxidation of reduced riboflavin-5′-phosphate with a long-chain aliphatic aldehyde and molecular oxygen, and the peak light emission generally occurs around 490 nm . This reaction is called luciferase–luciferinr eaction, and bacterial luciferase contains alpha and beta subunits named as luxA and luxB, respectively. 

     Modification of the light emission spectrum is often observed in luminous organisms, such as Aequorea victoria and has been observed in three species of luminous bacteria (Photobacterium)  phosphoreum, Photobacterium leiognathi, and Aliivibrio sifiae strain Y1 [known as Vibrio fischeri strainY1]. The mechanism of this phenomenon was initially characterized in P. phosphoreum strain A-13. The maximal emission wavelength ( 476 nm) of this strain is blue-shifted in comparison with that of purified luciferase (kmax  490 nm). Gast & Lee (1978) proved that this blue shift was caused by thei nvolvement of an accessory blue fluorescent protein, of the fluorescent spectrum was identical to the in vivo light emission spectrum. This protein was also found in P. leiognathi and is now called lumazine protein (LumP). 

Akanksha Joshi,

Microbiol,

RSML