''Endozoicomonas gorgoniicola'' is a

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

and facultative anaerobic bacterium from the genus of ''

Endozoicomonas ''Endozoicomonas'' is a genus of Gram-negative, aerobic or facultatively anaerobic, chemoorganotrophic, rod-shaped, marine bacteria from the family of Hahellaceae. ''Endozoicomonas'' are symbionts of marine animals. Scientific History The ge ...

''. Individual cells are motile and

rod-shaped A bacillus (), also called a bacilliform bacterium or often just a rod (when the context makes the sense clear), is a rod-shaped bacterium or archaeon. Bacilli are found in many different taxonomic groups of bacteria. However, the name '' Baci ...

. Bacteria in this genus are symbionts of coral. ''E. gorgoniicola'' live specifically with soft coral (family ''

Gorgoniidae Gorgoniidae is a family of soft corals, a member of the subclass Octocorallia in the phylum Cnidaria. Nearly all the genera and species are native to the east and west coasts of America. Characteristics Originally the members of the family G ...

'') and were originally isolated from a species of ''

Plexaura Medical Research Plexaura is a coral that has a large amount of prostaglandins making it a great natural source of a compound called Prostaglandin A2. Prostaglandins can be extracted from Plexaura using dichloromethane/methanol and a rotary evapo ...

'', an

octocoral Octocorallia (also known as Alcyonaria) is a class of Anthozoa comprising around 3,000 species of water-based organisms formed of colonial polyps with 8-fold symmetry. It includes the blue coral, soft corals, sea pens, and gorgonians (sea fan ...

, off the coast of

Bimini Bimini is the westernmost district of the Bahamas and comprises a chain of islands located about due east of Miami. Bimini is the closest point in the Bahamas to the mainland United States and approximately west-northwest of Nassau. The popula ...

in the Bahamas. The presence of this bacterium in a coral microbiome is associated with coral health.

Morphology

''E. gorgoniicola'' is a

gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

cell, characterized by the outer and inner membranes that enclose a thin layer of peptidoglycan. Cells are typically rod-shaped, and are about 1.7-2.5 μm long (average 2.0μm) and 0.4-0.9μm in diameter (average 0.7μm). ''E. gorgoniicola'' possess flagella that allow for

motility Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ...

. When the bacterium is

plated Plating is a surface covering in which a metal is deposited on a conductive surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improv ...

on marine agar, colonies form creamy white circles 0.5-1mm in diameter.

Habitat

As with most microorganisms, ''E. gorgoniicola'' inhabits microhabitats along small scale abiotic gradients within a larger organism. This species is found in species of in the genus ''

'', a rod shaped soft coral. Many ''Endozoicomonas'' species are found in multiple coral hosts, but ''E. gorgoniicola'' has only been isolated in ''Plexaura''. Coral-associated bacteria inhabit the exoskeleton, in the tissues, and in mucus that covers the surface of coral polyps. The mucus layer is a unique and important feature of coral; it protects the polyp from unwanted pathogens and nutrients. Most of the anti-pathogenic properties of mucus come from bacteria, including ''Endozoicomonas'' species. The internal microhabitats of coral are also inhabited by

endosymbiotic An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within ...

microalgal

dinoflagellates The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates a ...

in the family ''Symbiodiniaceae''. Bacteria and these microalgal cells are harbored in the

gastrodermis The gastrodermis is the inner layer of cells that serves as a lining membrane of the gastrovascular cavity of Cnidarians. The term is also used for the analogous inner epithelial layer of Ctenophore Ctenophora (; ctenophore ; ) comprise a ph ...

and form a symbiotic relationship by recycling nutrients.

Metabolism

General

In the ocean, ''E. gorgoniicola'' can grow at a range of temperatures anywhere from 15-30°C. Cells will grow, albeit slowly, at salt concentrations above 4% and below 1%. As an endosymbiotic organism, ''E. gorgoniicola'' utilizes nutrients that the associated microalgal dinoflagellates produce from

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. ''E. gorgoniicola'' can use the photosynthate as an energy source, but more importantly, bacteria break down secondary compounds that the coral and microalgae produce as waste, such as dimethylsulfoniopropionate (DMSP). Without this symbiosis, toxic waste products would build up within the polyp.

Culture growth

Optimum growth of ''E. gorgoniicola'' occurs at 22-30 °C and pH 8.0. The salt content must be 2-3% NaCl, which is slightly lower than ocean salinity -

seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...

is generally 3.5% NaCl, or 35 parts per thousand. Growth occurs on marine agar 2216. In culture, ''E. gorgoniicola'' utilizes sugars such as lactose, maltose, D-mannose, and

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

as a carbon source

anaerobic respiration Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O2). Although oxygen is not the final electron acceptor, the process still uses a respiratory electron transport chain. In aerobic organisms undergoing r ...

. It is a

facultative aerobic organism A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...

and can switch to fermentation when oxygen is absent. These bacteria are not able to reduce nitrate, which is a function crucial to coral health; however, ''E. gorgoniicola'' contribute to the symbiosis through sulfate reduction.

Genetics

The 16S rRNA regions of DNA from pure ''E. gorgoniicola'' colonies were sequenced and found to be novel strains of ''Endozoicomonas''. DNA can be extracted from this species using the eubacterial 16S rRNA gene primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1525R (5'AAGGAGGTGATCCAGCC-3'). It is closely related to the previously named ''E. elysicola'', as well as ''E. montiporae'' and ''E. numazuensis''. All are isolated from gorgonian (soft) corals. As of 2018, 1556 base pairs of rRNA have been sequenced from the ''E. gorgoniicola'' genome. The related species ''E. montiporae'' has a genome of about 5.4 million base pairs, and functions similarly to ''E. gorgoniicola'', suggesting they may have a similar sized genome.

References

External links

Type strain of ''Endozoicomonas gorgoniicola'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
* {{Taxonbar, from=Q60760212 Oceanospirillales Bacteria described in 2013