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Journal ArticleDOI

Pineal organs of deep-sea fish: photopigments and structure.

15 Jun 2004-The Journal of Experimental Biology (J Exp Biol)-Vol. 207, Iss: 14, pp 2379-2387
TL;DR: The morphology and photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish, scaly dragon-fish and bristlemouths, were examined, and two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rodphotopigment.
Abstract: We have examined the morphology and photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal photopigment was spectrally distinct from the retinal rod pigment, with lambdamax displaced to longer wavelengths, between approximately 485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi, caught at depths below 2000 m, which possesses a rod visual pigment with lambdamax at 478 nm, but the pineal pigment has lambdamax at approximately 515 nm. In one species of hatchet fish, Argyropelecus affinis, two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod photopigment.

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Citations
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Journal ArticleDOI
TL;DR: The results of the present study provide the first evidence that melatonin enhances TH expression in specific brain regions in a non‐mammalian species, and could represent one pathway by which environmental factors could modulate reproductive function in the eel.
Abstract: In the eel, a deficit in gonadotrophin-releasing hormone (GnRH) and a strong dopaminergic (DA) inhibition are responsible for the blockade of gonad development if silver eels are prevented from their reproductive migration. Environmental factors that eels encounter during their oceanic reproductive migration are thought to play an important role in the stimulation of eel pubertal development. We investigated the potential role of melatonin, a known mediator of the effects of external factors on reproductive function in vertebrates. We demonstrated that a long-term melatonin treatment increased brain tyrosine hydroxylase (TH, the rate limiting enzyme of DA synthesis) mRNA expression in a region-dependent way. Melatonin stimulated the dopaminergic system of the preoptic area, which is involved in the inhibitory control of gonadotrophin [luteinising hormone (LH) and follicle-stimulating hormone (FSH)] synthesis and release. Moreover, we showed that the increased TH expression appeared to be consistent with melatonin binding site distribution as shown by 2[(125)I]-melatonin labelling studies. On the other hand, melatonin had no effects on the two eel native forms of GnRH (mGnRH and cGnRH-II) mRNA expression. Concerning the pituitary-gonad axis, we showed that melatonin treatment decreased both gonadotrophin beta-subunit (LHbeta, FSHbeta) mRNA expression and reduced sexual steroid (11-ketotestosterone, oestradiol) plasma levels. This indicates that melatonin treatment had a negative effect on eel reproductive function. To our knowledge, the results of the present study provide the first evidence that melatonin enhances TH expression in specific brain regions in a non-mammalian species. By this mechanism melatonin could represent one pathway by which environmental factors could modulate reproductive function in the eel.

83 citations

Journal ArticleDOI
TL;DR: The first evidence of relative photoreception in teleosts was obtained in cod suggesting that the definition of illuminance thresholds (day/night perception) would depend on the day intensity, and a single order of magnitude increase or decrease in day intensity was shown to elicit a significant shift in the intensity response curve of night-time melatonin suppression.

74 citations

Journal ArticleDOI
TL;DR: This review will focus on the behavioural rhythms of crustacean decapods inhabiting depths where the sun light is absent, and potential scenarios for future research on deep-sea decapod behaviour are suggested by new in situ observation technologies.
Abstract: Ocean waters deeper than 200 m cover 70% of the Earth's surface. Light intensity gets progressively weaker with increasing depth and internal tides or inertial currents may be the only remaining zeitgebers regulating biorhythms in deep-sea decapods. Benthopelagic coupling, exemplified by vertically moving shrimps within the water column, may also act as a source of indirect synchronisation to the day-night cycle for species living in permanently dark areas. At the same time, seasonal rhythms in growth and reproduction may be an exogenous response to spring-summer changes in upper layer productivity (via phytoplankton) or, alternatively, may be provoked by the synchronisation mediated by an endogenous controlling mechanism (via melatonin). In our review, we will focus on the behavioural rhythms of crustacean decapods inhabiting depths where the sun light is absent. Potential scenarios for future research on deep-sea decapod behaviour are suggested by new in situ observation technologies. Permanent video observatories are, to date, one of the most important tools for marine chronobiology in terms of species recognition and animals' movement tracking.

61 citations

Journal ArticleDOI
26 Oct 2009-Sensors
TL;DR: A morphometry-based protocol for automated video-image analysis where animal movement tracking (by frame subtraction) is accompanied by species identification from animals' outlines by Fourier Descriptors and Standard K-Nearest Neighbours methods is elaborated.
Abstract: The understanding of ecosystem dynamics in deep-sea areas is to date limited by technical constraints on sampling repetition. We have elaborated a morphometry-based protocol for automated video-image analysis where animal movement tracking (by frame subtraction) is accompanied by species identification from animals' outlines by Fourier Descriptors and Standard K-Nearest Neighbours methods. One-week footage from a permanent video-station located at 1,100 m depth in Sagami Bay (Central Japan) was analysed. Out of 150,000 frames (1 per 4 s), a subset of 10.000 was analyzed by a trained operator to increase the efficiency of the automated procedure. Error estimation of the automated and trained operator procedure was computed as a measure of protocol performance. Three displacing species were identified as the most recurrent: Zoarcid fishes (eelpouts), red crabs (Paralomis multispina), and snails (Buccinum soyomaruae). Species identification with KNN thresholding produced better results in automated motion detection. Results were discussed assuming that the technological bottleneck is to date deeply conditioning the exploration of the deep-sea.

56 citations


Cites background from "Pineal organs of deep-sea fish: pho..."

  • ...The physiological and behavioural response of deep-sea fishes and crustaceans to rhythmic changes in bottom currents was already characterized in the Atlantic [5,29-31]....

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Journal ArticleDOI
01 Nov 2007
TL;DR: Observations strongly suggest that biological rhythms are present in demersal fish, the melatonin metabolism shows signs of periodicity, and tidal currents may act as zeitgeber at the bottom of the deep sea.
Abstract: We have studied physical and biological rhythms in the deep demersal habitat of the Northeastern Atlantic. Current velocity and direction changes occurred at intervals of 12.4 h, demonstrating that they could have an impact of tidal activity, and also showed indications of other seasonal changes. As an indicator of biological rhythms, we measured the content of pineal and retinal melatonin in the grenadier Coryphaenoides armatus and the deep-sea eel Synaphobranchus kaupii, and determined the spontaneous release of melatonin in long-term (52 h minimum) cultures of isolated pineal organs and retinae in S. kaupii. The results of the release experiments show statistically significant signs of synchronicity and periodicity suggesting the presence of an endogenous clock. The melatonin content data show large error bars typical of cross-sectional population studies. When the data are plotted according to a lunar cycle, taken as indication of a tidal rhythm, both species show peak values at the beginning of the lunar day and night and lower values during the second half of lunar day and night and during moonrise and moonset. Statistical analysis, however, shows that the periodicity of the melatonin content is not significant. Taken together these observations strongly suggest that (1) biological rhythms are present in demersal fish, (2) the melatonin metabolism shows signs of periodicity, and (3) tidal currents may act as zeitgeber at the bottom of the deep sea.

54 citations

References
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BookDOI
31 Jan 1999
TL;DR: The aim of this work is to provide a Discussion of Vertebrate Optical Structure and Visual Fields in Birds: Their Relationships with Foraging Behaviour and Ecology G.H. Jacobs and to clarify the role of light in the interaction between birds and the environment.
Abstract: Preface J Woods I: General Principles 1 Light and Photoreception E Loew, S Archer II: Biophysical Adaptations Introduction J Partridge 2 Compound Eye Structure: Matching Eye to Environment MF Land 3 Vertebrate Optical Structure JG Sivak, et al 4 A Review of Vertebrate and Invertebrate Optical Filters RH Douglas, NJ Marshall 5 Vertebrate Photoreceptors A Locket 6 The Extraretinal Photoreceptors of Non-Mammalian Vertebrates J Shand, RG Foster 7 The Regulation of Vertebrate Biological Clocks by Light RG Foster, I Provencio III: Biochemical and Physiological Adaptations Introduction S Archer, MBA Djamgoz 8 Adaptation of Visual Pigments to the Aquatic Environment JC Partridge, ME Cummings 9 Visual Adaptations in Crustaceans: Spectral Sensitivity in Diverse Habitats J Marshall, et al 10 Outer Retinal Signal Processing M Djamgoz, et al 11 Inner Retinal Signal Processing Adaptation to Environmental Light L Frishman 12 Ecological Aspects of Vertebrate Visual Ontogeny L Beaudet, CW Hawryshyn 13 Molecular Biology of Photoreceptor Spectral Sensitivity JK Bowmaker, DM Hunt IV: Behaviour and Communication Introduction E Loew 14 Visual Systems, Behaviour and Environment in Cephalapods W Muntz 15 Optical Structure and Visual Fields in Birds: Their Relationships with Foraging Behaviour and Ecology G Martin 16 Behavioural Ecology and Retinal Cell Topography S Collin 17 Flower Advertisement for Invertebrates: Bees, A Case Study M Vorobyev, R Menzel 18 Bioluminescence E Widder 19 The Behaviour of Animals around Twilight with Emphasis on Coral Reef Communities W McFarland, et al 20 Vision and Behaviour in Primates GH Jacobs

288 citations


"Pineal organs of deep-sea fish: pho..." refers background in this paper

  • ...It has long been argued that the rod pigments of deep-sea fish are spectrally tuned to match the maximum irradiance of the down-welling daylight and/or the maximum emission of the majority of bioluminescence (for recent reviews, see Douglas et al., 1998; Partridge and Cummings, 1999)....

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Journal ArticleDOI
TL;DR: There are strong indications that the pineal organ is one component in a central neural system that constitutes the photoperiod-responding system of the animal, i.e. the system that is responsible for correct timing of daily and seasonal physiological rhythms.
Abstract: The pineal organ of teleost fish is a directly photosensory organ that contains photoreceptor cells similar to those of the retina. It conveys photoperiod information to the brain via neural pathways and by release of indoleamines, primarily melatonin, into the circulation. The photoreceptor cells respond to changes in ambient illumination with a gradual modulation of neurotransmission to second-order neurons that innervate various brain centres, and by modulation of indoleamine synthesis. Melatonin is produced rhythmically, and melatonin synthesis may be regulated either directly by ambient photoperiod, or by an endogenous circadian oscillator that is entrained by the photoperiod. During natural conditions, melatonin is produced at highest levels during the night. Although the pineal organ undoubtedly influences a variety of physiological parameters, as assessed by experimental removal of the pineal organ and/or administration of exogenous indoleamines, its role in any physiological situation is not clear cut. The effects of any interference with pineal functions appear to vary with the time of year and experimental photothermal regimes. There are strong indications that the pineal organ is one component in a central neural system that constitutes the photoperiod-responding system of the animal, i.e. the system that is responsible for correct timing of daily and seasonal physiological rhythms. It is important to envisage the pineal organ as a part of this system; it interacts with other photosensory structures (the retina, possibly extraretinal non-pineal photoreceptors) and circadian rhythm generators

279 citations


"Pineal organs of deep-sea fish: pho..." refers background in this paper

  • ...Since pineal photoreceptors in fish start to differentiate even prior to retinal ones (Ekström and Meissl, 1997; Negishi and Wagner, 1995), it is feasible to assume that pineal organs in the eel, but probably in deep-sea fish in general, develop in a photic environment and differentiate to assume a…...

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  • ...Immunohistochemical studies have demonstrated that the photoreceptor cells contain elements of both the phototransduction cascade and the melatonin biosynthetic pathway (Ekström and Meissl, 1997)....

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  • ...The pineal is thus designed to detect slowly changing ambient light levels, ideal for the photic control of circadian and seasonal behaviour (Ekström and Meissl, 1997)....

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  • ...The luminal side of the epithelium is formed mostly by photoreceptor and non-photoreceptor cells, often referred to as supporting cells (Ekström and Meissl, 1997)....

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Journal ArticleDOI
TL;DR: Evidence is presented that the λmax of visual pigments are not distributed uniformly throughout the spectrum but, on the contrary, are clustered around certain discrete positions.

265 citations


"Pineal organs of deep-sea fish: pho..." refers background in this paper

  • ...The λmax of rod visual pigments of deep-sea fish tend to cluster at specific spectral locations (Dartnall and Lythgoe, 1965; Partridge et al., 1989) and the basis for this lies in specific amino acid substitutions within the opsins of the pigments that cause clearly defined spectral displacements…...

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Journal ArticleDOI
TL;DR: This review hopes to convince the more casual reader that there is much more to vertebrate photoreceptors than the study of retinal rods and cones, and that inner retinal photoreception will be a feature of all vertebrates.

180 citations


"Pineal organs of deep-sea fish: pho..." refers background in this paper

  • ...At least two of these, VA opsin (Foster and Hankins, 2002; Kojima et al., 2000; Moutsaki et al., 2000; Soni and Foster, 1997) and parapinopsin (Blackshaw and Snyder, 1997), have been located in areas associated with the teleost pineal....

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Journal ArticleDOI
TL;DR: Some general design considerations, the character and performance of the equipment, and some of the results obtained with retinal cones are reviewed.
Abstract: A microspectrophotometer of exceptional sensitivity has been constructed to record absorption spectra of visual pigments in single cells using minimum light. With this equipment, pigments of individual cones have been recorded in regions of less than 1 μ radius, with minimum bleaching. The instrument is simple and flexible in design, and uses commercially available components throughout. This paper reviews some general design considerations, the character and performance of our equipment, and some of the results obtained with retinal cones.

179 citations


"Pineal organs of deep-sea fish: pho..." refers methods in this paper

  • ...Microspectrophotometric recordings were made in the conventional manner using a Liebman dual-beam microspectrophotometer (Bowmaker et al., 1991; Liebman and Entine, 1964; Mollon et al., 1984)....

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