Bioluminescent Dinoflagellates are Kinetitrophic Organisms

In previous posts I stated that I think bioluminescent dinoflagellates are exhibiting a special type of autotrophic behavior, converting kinetic energy into chemical energy.  I call the process kinetisynthesis or kinetitrophic behavior.  The organisms release a short flash of light in response to a fairly significant input of kinetic energy, caused by a wave or turbulence.  I think the light is evidence of a chemical ratchet or click mechanism—the release of light forces a conformation change of the molecule that releases light, thereby locking the energy. 

The chemicals behind the light-producing mechanism in bioluminescent dinoflagellates are well known.  Three chemical compounds are known to be involved.  One is called luciferin, a second is called luciferase, and a third is called luciferin binding protein, or LBP.

The release of the light in dinoflagellate luminescence occurs in small cellular organelles called scintillons.  A model that proposes how this work is published by Margaret Fogel and J. W. Hastings, 1972, and is repeated in detail in a web paper by Hastings, Schultz, and Liu, dated 2-5-09.

The model suggests that bending of membranes in the cell causes H+ ions to be released.  The luciferin accepts a proton and instantly releases light.  There is also a conformation change in the luciferin molecule.

The prevailing view, which I will call the “energy use” idea (because it suggests that the cell uses metabolic energy to produce the light), has this as the triggering mechanism for the flash.

My view, which I will call the “ratchet” idea, says that the luciferin molecule is a molecular ratchet. The light released is evidence of a chemical click mechanism that forces the energy in one direction.  The cell gains metabolic energy as a result of the bioluminescence. 

While a lot is known about the chemistry involved in dinoflagellate bioluminescence, much is still unknown, including exactly how the energy is transferred.

I think the Fogel/Hastings model makes more of a case for the ratchet idea than it does for the energy use idea.

About the roused bear

Nature photographer from central Iowa.
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