A Microbial Biorealm page on the genus Photobacterium phosphoreum
Higher order taxa
No rank: Cellular Organisms
Species: Photobacterium phosphoreum
Description and significance
Photobacterium phosphoreum was first isolated from the aquatic environment in the late 1880’s by the Dutch microbiologist Martinus Beijerinck (1851-1931). It is a Gammaproteobacteria which are Gram-negative, usually motile rods, are mesophilic and chemoorganotrophic, have falcultative fermentative metabolism and are found in aquatic habitats in association with eukaryotes.
Photobacterium phosphoreum is one of many organisms that produce bioluminescence in marine organisms. P. phosphoreum is a light organ symbiont, living in the gut of the fish where metabolites are provided in exchange for bioluminescence, which is used for communication, prey attraction, and predator avoidance. P. phosphoreum typical of deep sea fishes, which can also be found in dim and dark versions. The gut of the fish, where P. phosphoreum is cultivated, is connected to some light organ on the fish which can be controlled with shutter apparatuses. P. phosphoreum is psychrotolerant and often thrives in low temperatures but can be inhibited at temperatures above 25 degrees Celcius.[13, 15] Bioluminescence has been strongly linked to cell density, and bacteria living freely in the ocean are not bioluminescent as they are in the light organs of the host organism.
P. phosphoreum also acts as the most important spoilage bacterium of packed chilled fish fillets. It enhances growth in packed fish products and causes the spoiled, fishy flavor.
The gene products of luxA, α-luciferase, are necessary for the light-emitting reaction of all known luminous bacteria. Unlike the Vibrio lux system, P. phosphoreum has a new gene, luxF which is located in the lux operon between luxB and luxE. The functions of the luxA to E gene products are known to be involved in the luminescent pathway, luxF likely has the same function. The organization of the lux operon in P. phosphoreum is as follows: luxC luxD luxA luxB luxF luxE.
In P. phosphoreum, luxA and luxB gene products are luciferase subunits and were shown to catalyze light emission in the presence of FMNH2, O2, and aldehyde. The luxC, luxD, and luxE gene products are fatty acid reductase subunits and are responsible for aldehyde biosynthesis. The new gene, luxF, was found to code for a new polypeptide of 26kDa.
Cell structure and metabolism
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Enter summaries of the most recent research here--at least three required
[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.
Edited by student of Rachel Larsen