Browsing Bergen Open Research Archive by Author "Helvik, Jon Vidar"
Now showing items 1-13 of 13
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An EvoDevo Study of Salmonid Visual Opsin Dynamics and Photopigment Spectral Sensitivity
Eilertsen, Mariann; Davies, Wayne I. L.; Patel, Dharmeshkumar; Barnes, Jonathan E.; Karlsen, Rita; Mountford, Jessica Kate; Stenkamp, Deborah; Patel, Jagdish Suresh; Helvik, Jon Vidar (Journal article; Peer reviewed, 2022)Salmonids are ideal models as many species follow a distinct developmental program from demersal eggs and a large yolk sac to hatching at an advanced developmental stage. Further, these economically important teleosts ... -
The exorhodopsin and melanopsin systems in the pineal complex and brain at early developmental stages of Atlantic halibut (Hippoglossus hippoglossus)
Eilertsen, Mariann; Drivenes, Øyvind; Edvardsen, Rolf; Bradley, Clarissa A.; Ebbesson, Lars O.E.; Helvik, Jon Vidar (Journal article; Peer reviewed, 2014)The complexity of the nonvisual photoreception systems in teleosts has just started to be appreciated, with colocalization of multiple photoreceptor types with unresolved functions. Here we describe an intricate expression ... -
Heads and tails: The notochord develops differently in the cranium and caudal fin of Atlantic Salmon (Salmo salar, L.)
Kryvi, Harald; Nordvik, Kari; Fjelldal, Per Gunnar; Eilertsen, Mariann; Helvik, Jon Vidar; Støren, Eivind Wilhelm Nagel; Long, John H. (Journal article; Peer reviewed, 2020)While it is well known that the notochord of bony fishes changes over developmental time, less is known about how it varies across different body regions. In the development of the Atlantic salmon, Salmo salar L., cranial ... -
Light conditions during Atlantic salmon embryogenesis affect key neuropeptides in the melanocortin system during transition from endogenous to exogenous feeding
Norland, Sissel; Gomes, Ana S.; Rønnestad, Ivar; Helvik, Jon Vidar; Eilertsen, Mariann (Journal article; Peer reviewed, 2023)During the first feeding period, fish will adapt to exogenous feeding as their endogenous source of nutrients is depleted. This requires the development of a functional physiological system to control active search for ... -
Mapping key neuropeptides involved in the melanocortin system in Atlantic salmon (Salmo salar) brain
Norland, Sissel; Eilertsen, Mariann; Rønnestad, Ivar; Helvik, Jon Vidar; Gomes, Ana S. (Journal article; Peer reviewed, 2023)The melanocortin system is a key regulator of appetite and food intake in vertebrates. This system includes the neuropeptides neuropeptide y (NPY), agouti-related peptide (AGRP), cocaine- and amphetamine-regulated transcript ... -
Mapping the pattern of essential neuroendocrine cells related to puberty and VA opsin expression provides further insight in the photoreceptive regulation of the BPG axis in Atlantic salmon (Salmo salar)
Horne, Christine; Helvik, Jon Vidar; Fleming, Mitchell Stewart; Fjelldal, Per Gunnar; Eilertsen, Mariann (Journal article; Peer reviewed, 2022)In Atlantic salmon (Salmo salar), seasonal photoperiod is shown to regulate the onset of sexual maturation, yet which brain region(s) is involved, and how light information impacts the neuroendocrine system are still not ... -
Molecular evidence that only two opsin subfamilies, the blue light- (SWS2) and green light-sensitive (RH2), drive color vision in Atlantic cod (Gadus morhua)
Valen, Ragnhild; Edvardsen, Rolf; Søviknes, Anne Mette; Drivenes, Øyvind; Helvik, Jon Vidar (Peer reviewed; Journal article, 2014-12-31)Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision) including rod opsin only retinas seen in ... -
Neural activation in photosensitive brain regions of Atlantic salmon (Salmo salar) after light stimulation
Eilertsen, Mariann; Clokie, Benjamin G.J.; Ebbesson, Lars; Tanase, Cristina; Migaud, Herve; Helvik, Jon Vidar (Journal article; Peer reviewed, 2021)Photoreceptive inputs to the teleost brain are perceived as image of the visual world and as photo-modulation of neuroendocrine and neuronal signals. The retina and pineal organ are major receptive organs with projections ... -
Photoreception and transcriptomic response to light during early development of a teleost with a life cycle tightly controlled by seasonal changes in photoperiod
Eilertsen, Mariann; Dolan, David William Peter; Bolton, Charlotte M.; Karlsen, Rita; Davies, Wayne I.L.; Edvardsen, Rolf Brudvik; Furmanek, Tomasz; Sveier, Harald; Migaud, Herve; Helvik, Jon Vidar (Journal article; Peer reviewed, 2022)Light cues vary along the axis of periodicity, intensity and spectrum and perception of light is dependent on the photoreceptive capacity encoded within the genome and the opsins expressed. A global approach was taken to ... -
Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides
Busserolles de, Fanny; Cortesi, Fabio; Helvik, Jon Vidar; Davies, Wayne I. L.; Templin, Rachel M.; Sullivan, Robert K. P.; Michell, Craig T.; Mountford, Jessica K.; Collin, Shaun P.; Irigoien, Xabier; Kaartvedt, Stein; Marshall, Justin (Peer reviewed; Journal article, 2017)Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light ... -
Rhythmic Clock Gene Expression in Atlantic Salmon Parr Brain
Bolton, Charlotte M.; Bekaert, Michaël; Eilertsen, Mariann; Helvik, Jon Vidar; Migaud, Herve (Journal article; Peer reviewed, 2021)To better understand the complexity of clock genes in salmonids, a taxon with an additional whole genome duplication, an analysis was performed to identify and classify gene family members (clock, arntl, period, cryptochrome, ... -
Transient photoreception in the hindbrain is permissive to the life history transition of hatching in Atlantic halibut
Eilertsen, Mariann; Valen, Ragnhild; Drivenes, Øyvind; Ebbesson, Lars O.E.; Helvik, Jon Vidar (Journal article; Peer reviewed, 2018)In nonmammalian vertebrates, photoreception takes place in the deep brain already early in development, but knowledge is lacking about the functions of these nonvisual photoreceptive systems. Prior to hatching, Atlantic ... -
The two-step development of a duplex retina involves distinct events of cone and rod neurogenesis and differentiation
Valen, Ragnhild; Eilertsen, Mariann; Edvardsen, Rolf; Furmanek, Tomasz; Rønnestad, Ivar; van der Meeren, Terje; Karlsen, Ørjan; Nilsen, Tom Ole; Helvik, Jon Vidar (Peer reviewed; Journal article, 2016-08)Unlike in mammals, persistent postembryonic retinal growth is a characteristic feature of fish, which includes major remodeling events that affect all cell types including photoreceptors. Consequently, visual capabilities ...