dc.contributor.author	Fasick, Jeffry I.
dc.contributor.author	Algrain, Haya
dc.contributor.author	Samuels, Courtland
dc.contributor.author	Mahadevan, Padmanabhan
dc.contributor.author	Schweikert, Lorian E.
dc.contributor.author	Naffaa, Zaid J.
dc.contributor.author	Robinson, Phyllis R.
dc.date.accessioned	2021-11-10T18:04:12Z
dc.date.available	2021-11-10T18:04:12Z
dc.date.issued	2021-10-15
dc.description.abstract	In mammals, the photopigment melanopsin (Opn4) is found in a subset of retinal ganglion cells that serve light detection for circadian photoentrainment and pupil constriction (i.e., mydriasis). For a given species, the efficiency of photoentrainment and length of time that mydriasis occurs is determined by the spectral sensitivity and deactivation kinetics of melanopsin, respectively, and to date, neither of these properties have been described in marine mammals. Previous work has indicated that the absorbance maxima (λmax) of marine mammal rhodopsins (Rh1) have diversified to match the available light spectra at foraging depths. However, similar to the melanopsin λmax of terrestrial mammals (~480 nm), the melanopsins of marine mammals may be conserved, with λmax values tuned to the spectrum of solar irradiance at the water’s surface. Here, we investigated the Opn4 pigments of 17 marine mammal species inhabiting diverse photic environments including the Infraorder Cetacea, as well as the Orders Sirenia and Carnivora. Both genomic and cDNA sequences were used to deduce amino acid sequences to identify substitutions most likely involved in spectral tuning and deactivation kinetics of the Opn4 pigments. Our results show that there appears to be no amino acid substitutions in marine mammal Opn4 opsins that would result in any significant change in λmax values relative to their terrestrial counterparts. We also found some marine mammal species to lack several phosphorylation sites in the carboxyl terminal domain of their Opn4 pigments that result in significantly slower deactivation kinetics, and thus longer mydriasis, compared to terrestrial controls. This finding was restricted to cetacean species previously found to lack cone photoreceptor opsins, a condition known as rod monochromacy. These results suggest that the rod monochromat whales rely on extended pupillary constriction to prevent photobleaching of the highly photosensitive all-rod retina when moving between photopic and scotopic conditions.	en_US
dc.description.sponsorship	Funding acquisition: Jeffry I. Fasick, Phyllis R. Robinson	en_US
dc.description.uri	https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0257436	en_US
dc.format.extent	6 files	en_US
dc.genre	journal articles	en_US
dc.identifier	doi:10.13016/m25xdv-uzyy
dc.identifier.citation	Fasick, Jeffry I. et al.; Spectral tuning and deactivation kinetics of marine mammal melanopsins; PLOS ONE 16, 10, 15 October, 2021; https://doi.org/10.1371/journal.pone.0257436	en_US
dc.identifier.uri	https://doi.org/10.1371/journal.pone.0257436
dc.identifier.uri	http://hdl.handle.net/11603/23298
dc.language.iso	en_US	en_US
dc.publisher	PLOS	en_US
dc.relation.isAvailableAt	The University of Maryland, Baltimore County (UMBC)
dc.relation.ispartof	UMBC Biological Sciences Department Collection
dc.relation.ispartof	UMBC Student Collection
dc.rights	This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.	en_US
dc.rights	Attribution 4.0 International (CC BY 4.0)	*
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	*
dc.title	Spectral tuning and deactivation kinetics of marine mammal melanopsins	en_US
dc.type	Text	en_US

Spectral tuning and deactivation kinetics of marine mammal melanopsins

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