Bioluminescent bacteria - Wikipedia
Symbiotic Luminescent Bacteria in Fish Light Organs oxygen. The correlation of purine concentrations in the bladder of pony fishes with the path of light indi-. Bathypelagic species, such as the angler fishes, inhabit the deeper part of bacteria and deep sea fish maintain a symbiotic relationship to give the fish a LuxA and LuxB catalyze the luciferase reaction, using oxygen and a. The fish maintain their bacteria in gland-like tissue complexes called light organs, the anatomical within each fish family, with oxygen and nutrients for luminescence and reproduction. .. Occurrence of Vibrio harveyi in light organ symbiosis.
These bacteria, as mentioned above, all exhibit similar characteristics in terms of their use of quorum sensing, and the luciferase reaction. As mentioned above, they are a very quorum—sensitive species, only being activated when a certain threshold limit is reached.
The autoinducer in Vibrio fischeri is N- 3-oxohexanoyl homoserine lactone: Vibrio fischeri maintain a symbiotic relationship with a small Hawaiian squid, which provides for a safe environment for the bacteria, while receiving aid in hunting at night.
They do however exhibit harmful pathogen characteristics towards fish and invertebrates, as they can cause a wide variety of infections and diseases in these organisms.
It carries similar properties as Vibriro fischeri in terms of its symbiotic relationship with the host organism, its reaction to create light, and its use of quorum sensing. For example, many deep seas are found beyond the exclusive economic zone of individual nations on the High seas, which are an open access to all nations for fishing activities. Due to these over-exploited and unregulated activities, deep sea is under multiple threats including climate change, acidification, and possible extinction of some species.
While it has been previously viewed that deep sea was protective from the effects of surface driven cycles and impacts, modern research shows that this may not be true after all. During the study done approximately 4 years ago, it was found that increasing fresh water input from terrestrial sources may disrupt thermohaline circulation, changing ocean circulation patterns as well as the temperature and the density.
As more threats to the deep sea communities are discovered recently, we still lack sound scientific basis for restoring the habitats and protecting them. Thus, it is believed that more research needs to be conducted to solve some of the problems.True Facts About The Angler Fish
A bioluminescent bacteria, Vibrio harveyi is considered to be deadly to many cultured animals. In order to find the cure for some of this bacterial causing diseases, since quorum sensing is involved pathological events such as biofilm formation and and bacterial virulence, researches involving quorum sensing inhibitors are being conducted. Autoinducer-2 AI-2 mediates the quorum sensing in both gram positive and gram negative bacteria. This molecule exists in complex with boric acid with complex F being the biologically active form of V.
Anglerfish and their headlamp bacteria have a crazy relationship
This complex binds to the LuxP receptor in V. Hence, in order to inhibit this activity, the research involves mimicking of the boric acid complex F with structurally similar compound boronic acid.
By binding this molecule to the LuxP site, antagonizing of the bacterial quorum sensing can be made possible. In conclusion, after screening 50 boronic acid compounds for their ability to inhibit quorum sensing activity, the result showed that several phenylboronic acids exhibited AI-2 inhibition effect.
Anglerfish and their headlamp bacteria have a crazy relationship - Futurity
This can be a very useful tool as well as a good lead to future researches. Milky sea, a continuous and substancial light emission from the surface of the ocean, has been the subject of a study in terms of what causes the light emission.
Marine bioluminescent organisms emit light as brief flashes milliseconds or seconds or discontinuous bursts lasting for minutes at most and cannot be responsible for the prolonged emission of light by the "milky seas". Bioluminescent bacteria seemed like an unlike source of light also since it was thought that the autoinducer of quorum sensing cannot accumulate at required concentration in the open ocean. LuxI is autoinducer synthase that produces autoinducer AI while LuxR functions as both a receptor and transcription factor for the lux operon.
Unlike Aliivibrio fischeriV. Instead, they use the system known as three-channel quorum sensing system. Its benefits for bacteria, however, still remain unclear.
Several studies have shown the biochemical roles of the luminescence pathway. It can function as an alternate pathway for electron flow under low oxygen concentration, which can be advantageous when no fermentable substrate is available.
Evidence also suggests that bacterial luciferase contributes to the resistance of oxidative stress. In laboratory culture, luxA and luxB mutants of Vibrio harveyiwhich lacked luciferase activity, showed impairment of growth under high oxidative stress compared to wild type.
The luxD mutants, which had an unaffected luciferase but were unable to produce luminescence, showed little or no difference. One explanation for why these bacteria might be undergoing evolution is that the fish once had an original bacterial symbiont and more recently acquired a new one. The researchers sequenced genomes of bioluminescent bacteria from two different species of anglerfish and found a different type of bacteria colonizing the bulb of each fish species.
The genomes showed large numbers of pseudogenes that are no longer functional, remnants of the original genome that will likely be lost over time. Both species of bacteria had the largest number of transposons mobile elements of DNA ever reported in a bacterial genome, each accounting for close to a third of their genomes.
Transposons move around the genome, insert themselves into other functional genes and make those sequences unfunctional. Since the bacterial genomes were different but each showed evidence of evolution taking place, the researchers concluded the evolution was happening independently in each lineage of bacteria. The study was funded by the Gulf of Mexico Research Initiative.