''Vibrio harveyi'' is a Gram-negative,

bioluminescent Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorganisms including ...

marine bacterium Marine prokaryotes are marine bacteria and marine archaea. They are defined by their habitat as prokaryotes that live in marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. All cellular ...

in the genus '' Vibrio''. ''V. harveyi'' is rod-shaped, motile (via polar

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

), facultatively anaerobic, halophilic, and competent for both fermentative and respiratory metabolism. It does not grow below 4 °C ( optimum growth: 30° to 35 °C). ''V. harveyi'' can be found free-swimming in tropical marine waters, commensally in the gut microflora of

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

animals, and as both a primary and opportunistic pathogen of marine animals, including Gorgonian corals, oysters, prawns,

lobster Lobsters are a family (biology), family (Nephropidae, Synonym (taxonomy), synonym Homaridae) of marine crustaceans. They have long bodies with muscular tails and live in crevices or burrows on the sea floor. Three of their five pairs of legs ...

s, the

common snook The common snook (''Centropomus undecimalis'') is a species of Seawater, marine fish in the family (biology), family Centropomidae of the order (biology), order Perciformes. The common snook is also known as the sergeant fish or robalo. It was o ...

, barramundi, turbot, milkfish, and seahorses. It is responsible for luminous vibriosis, a disease that affects commercially farmed penaeid prawns. Additionally, based on samples taken by ocean-going ships, ''V. harveyi'' is thought to be the cause of the

milky seas effect Milky seas, also called mareel, is a luminous phenomenon in the ocean in which large areas of seawater (up to ) appear to glow translucently (in varying shades of blue). Such occurrences glow brightly enough at night to be visible from satelli ...

, in which, during the night, a uniform blue glow is emitted from the seawater. Some glows can cover nearly .

Quorum sensing

Groups of ''V. harveyi'' bacteria communicate by quorum sensing to coordinate the production of bioluminescence and virulence factors. Quorum sensing was first studied in ''V. fischeri'' (now '' Aliivibrio fischeri''), a marine bacterium that uses a

synthase In biochemistry, a synthase is an enzyme that catalyses a synthesis process. Note that, originally, biochemical nomenclature distinguished synthetases and synthases. Under the original definition, synthases do not use energy from nucleoside tripho ...

(LuxI) to produce a species-specific

autoinducer Autoinducers are signaling molecules that are produced in response to changes in cell-population density. As the density of quorum sensing bacterial cells increases so does the concentration of the autoinducer. Detection of signal molecules by ba ...

(AI) that binds a cognate receptor (LuxR) that regulates changes in expression. Coined "LuxI/R" quorum sensing, these systems have been identified in many other species of Gram-negative bacteria. Despite its relatedness to ''A. fischeri'', ''V. harveyi'' lacks a LuxI/R quorum-sensing system, and instead employs a hybrid quorum-sensing circuit, detecting its AI through a membrane-bound

histidine kinase Histidine kinases (HK) are multifunctional, and in non-animal kingdoms, typically transmembrane, proteins of the transferase class of enzymes that play a role in signal transduction across the cellular membrane. The vast majority of HKs are homod ...

and using a phosphorelay to convert information about the population size to changes in gene expression. Since their identification in ''V. harveyi'', such hybrid systems have been identified in many other bacterial species. ''V. harveyi'' uses a second AI, termed autoinducer-2 or AI-2, which is unusual because it is made and detected by a variety of different bacteria, both Gram-negative and Gram-positive. Thus, ''V. harveyi'' has been instrumental to the understanding and appreciation of interspecies bacterial communication.

References

External links

''V. harveyi'' at NCBI

Vibrios at NCBIType strain of ''Vibrio harveyi'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q3761158 Vibrionales Bioluminescent bacteria Bacteria described in 1936