Back to Symposium home page 12th International Symposium on Bioluminescence & Chemiluminescence

Symposium abstracts:

A possible retinal longwave detecting system in a myctophid fish without far-red bioluminescence; evidence for a sensory arms-race in the deep-sea

Douglas, Ron H.1, Bowmaker, James K.2, Mullineaux, Conrad W.3

  1. Applied Vision Research Centre, Dept of Optometry & Visual Science, City University, Northampton Sq., London EC1V 0HB, U.K.
  2. Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, U.K.
  3. Dept of Biology, University College London, Darwin Building, Gower Street, London, WC1E 6BT, U.K.

Most deep-sea fish have visual pigments maximally sensitive (lmax) at 460-490 nm, approximately matching the spectral composition of both residual sunlight and mesopelagic bioluminescence. 3 genera of red light producing stomiid dragon fish, however, have eyes sensitive to longer wavelengths, affording them a ‘secret waveband’ for communication and illumination of prey, immune from detection. Here we describe the retinal pigments of Bolinichthys longipes, which is not known to produce longwave bioluminescence but belongs to a family (myctophidae), which is heavily preyed upon by the stomiids. Retinal extracts show a single visual pigment with lmax 488 nm and a photostable pigment with an absorption profile similar to the chlorophyll-derived photosensitizing pigment employed by Malacosteus niger, one of the red light producing stomiids, to enhance longwave sensitivity. Fluorescence emission and excitation spectra of retinal extracts and homogenates show peaks at around 670 and 400 nm respectively, characteristic of chlorophyll-like pigments. Mirospectrophotometry shows that photoreceptors possessing the visual pigment described by extract do not contain the photostable pigment. Preliminary data indicate that it resides in cells along with a 553nm lmax visual pigment. Although we have no direct proof that the chlorophyll-like pigment in the B. longipes retina acts as a longwave photosensitizer, the data are suggestive of it, and it appears possible that this species possesses a mechanism allowing it to perceive the longwave bioluminescence produced by stomiids.

 

This is a preprint of an article accepted for publication in Luminescence: Copyright 2001 John
Wiley & Sons, Ltd (Wiley website)