The visual pigments of a deep‐sea myctophid fish Myctophum nitidulum Garman; an HPLC and spectroscopic description of a non‐paired rhodopsin–porphyropsin system

Abstract

Unusually for a deep-sea fish, the retina of the myctophid (lanternfish) Myctophum nitidulum was found to contain two visual pigments, shown by extract spectrophotometry to be maximally sensitive at 468 and 522 nm, respectively, giving this species one of the broadest spectral ranges of all deep-sea fishes. High performance liquid chromatography (HPLC) indicated that the retina contained both A 1 -and A 2 -based chromophores. Surprisingly, the maximum absorbance (l max ) values of the two visual pigments were too far apart to form a rhodopsin-porphyropsin 'pigment pair', suggesting they were based on distinct opsins each linked to a different chromophore. This might be an adaptation to the detection of both long-wave bioluminescence and residual shorter-wave surface illumination, and could be related to this animal's tendency to migrate towards surface waters at night.

Three cone opsin genes determine the properties of the visual spectra in the Japanese anchovy Engraulis japonicus (Engraulidae, Teleostei)

“…Standards were created using the same method described previously (Provencio et al, 1992). The peaks of the oximes were identified by the retention time of standard solutions using the same Shimadzu HPLC equipment and close working regime described above (Hasegawa et al, 2002;Hasegawa, 2005;Hasegawa et al, 2008). The relative quantity of oximes was evaluated by the amplitude or square of the chromatographic peaks at 360 and 400nm.…”

Multifunctional Roles of Melanocyte-Stimulating Hormone and Melanin-Concentrating Hormone in Fish: Evolution from Classical Body Color Change

“…A complete set of visual opsin genes such as red-sensitive, greensensitive, blue-sensitive, and ultraviolet-sensitive opsins along with rod opsins have been identified in freshwater fish living in shallow water, such as zebrafish (Chinen et al 2003;Takechi and Kawamura 2005) and medaka (Matsumoto et al 2006), whereas only rod opsins have been identified in various marine deep-water species of fish (Hope et al 1997;Hasegawa et al 2008). In flatfish members, Atlantic halibut, Hippoglossus hippoglossus, has been shown to possess the five opsins observed in shallow freshwater species (Helvik et al 2001).…”

Spectral Tuning in the Eyes of Deep-Sea Lanternfishes (Myctophidae): A Novel Sexually Dimorphic Intra-Ocular Filter

“…Lanternfishes generally lack cones and possess a single rod photoreceptor class with a peak spectral absorption tuned to the blue-green region of the visible spectrum [Partridge et al, 1992;Douglas and Partridge, 1997;Turner et al, 2009]. However, the presence of 2 photoreceptor classes has been found in a few species [Hasegawa et al, 2008;Turner et al, 2009]. In this study, we describe a novel visual adaptation, a retinal yellow pigmentation associated with a rod gene duplication, that is unique among vertebrates and assists lanternfishes to tune their visual sensitivity.…”

“…Ceratoscopelus warmingii [Douglas et al, 2003], H. proximum , M. aurolaternatum [Turner et al, 2009] and M. nitidulum [Hasegawa et al, 2008], with the last 3 species all possessing yellow pigmentation (this study). Based on the conclusions of this study and known relationships between the λ max values of A 1 and A 2 visual pigment pairs [Parry and Bowmaker, 2000], the presence of two different opsins can be predicted for H. proximum, M. nitidulum, [Hasegawa et al, 2008;Turner et al, 2009], M. obtusirostre and S. evermanni. This was confirmed at the molecular level for S. evermanni (this study).…”

“…Some of these far-red illuminating fishes are known to prey on myctophids [Sutton and Hopkins, 1996], and the long-waveshifted visual pigment in some of these lanternfishes (i.e. M. nitidulum and M. obtusirostre ) could potentially have evolved as a mechanism to detect these predators [Hasegawa et al, 2008;Turner et al, 2009].…”