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  • 1
    Electronic Resource
    Electronic Resource
    Circadian Rhythm of Melatonin Release From the Photoreceptive Pineal Organ of a Teleost, Ayu (Plecoglossus altivelis) in Flow-Thorough Culture (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 16 (2004), S. 0 
    Details
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the present study, we tested whether the pineal organ of ayu (Plecoglossus altivelis), an osmerid teleost close relative of salmonids, harbours a circadian oscillator regulating rhythmic melatonin release using flow-through culture. The pineal organ maintained under light/dark cycles released melatonin in a rhythmic fashion with high levels during the dark phase. A circadian rhythm of melatonin release persisted in constant darkness for at least four cycles. Characteristics of the circadian rhythm (free-running period, phase and amplitude) exhibited small variations among cultures when the data was normalized, indicating that this system is sufficient for the analysis of the circadian rhythm both at qualitative and quantitative levels. Six-hour extension of the light phase from the normal onset time of the dark phase or exposure to constant light for 36 or 48 h before transfer to constant darkness significantly inhibited melatonin release. Phase shifts in the circadian rhythm of melatonin release were also observed. Thus, the ayu pineal organ contains all the three essential components of the circadian system (a circadian clock, the photoreceptor responsible for photic entrainment of the clock, and melatonin generating system as an output pathway). This system should provide a useful model for analysing the physiological and molecular basis of the vertebrate circadian system. In addition, further comparative studies using salmonids and related species including ayu will provide some insight into the evolution of the roles of the pineal organ in the vertebrate circadian system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2826.2004.01132.x
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  • 2
    Electronic Resource
    Electronic Resource
    Self-selection and feed consumption of diets with a complete amino acid composition and a composition deficient in either methionine or lysine by rainbow trout, Oncorhynchus mykiss (Walbaum) (2001)
    Oxford, UK : Blackwell Science, Ltd
    Aquaculture research 32 (2001), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two feeding experiments were conducted to evaluate the ability of rainbow trout, Oncorhynchus mykiss (Walbaum), to discriminate the sufficiency of a single essential amino acid in diets using self-feeders. In experiment 1, 12 groups of 23–24 fish (initial weight; 25.3 ± 0.5 g) were acclimated to a casein-based low protein diet (crude protein, CP = 10%) for 2 weeks. They were then offered for 32 days a combination of two wheat gluten-based diets fortified by crystalline amino acids (CP = 40%), with a complete amino acid composition (complete) and a composition deficient in either methionine (Met-def) or lysine (Lys-def) (six groups per treatment). In the complete and Met-def diet selection groups, no specific preference for either of the diets was observed. However, in the complete and Lys-def diets selection groups, a preference for the complete diet increased gradually (P 〈 0.05, for the last 8-day period). In experiment 2, 12 groups of 21–22 fish (initial weight; 27.6 ± 0.5 g) were acclimated to a casein-based high protein diet (CP = 40%) for 2 weeks, and then the complete diet and one of the amino acid-deficient diets were offered alternately for 8-day intervals over 32 days (six groups per treatment). In the complete–Met-def diet groups, overall daily feed consumption (g tank−1) increased gradually, but that for the Met-def diet seemed nearly stable. In the complete–Lys-def diet group, feed consumption when the complete diet was offered increased, while it then decreased after the complete diet was replaced with the Lys-def diet. These results indicate that trout discriminate sufficiency of lysine in diets and regulate their feed consumption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1355-557x.2001.00007.x
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  • 3
    Electronic Resource
    Electronic Resource
    Circadian rhythms of demand-feeding and locomotor activity in rainbow trout (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 52 (1998), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Under free-running conditions, most rainbow trout displayed circadian feeding rhythms, although the expression of circadian rhythmicity depended on the experimental condition: 16·7% of fish under constant dim light (LL dim), 66·1% under a 45 :45 min light-dark cycle (LD pulses), and 83·8% under constant light (LL). Under LD pulses, the period length of the free-running rhythms for feeding was significantly shorter (21·9 ± 0·7 h, n=8) than under LL (26·2 ± 0·3 h, n=10). Period length for locomotor activity under LL was 25·8 ± 0·6 h (n=4). Under LD conditions, the daily demand-feeding profile was always confined to the light phase and chiefly composed of two main episodes, directly after lights on (light elicited) and in anticipation to lights off (endogenous). Contrasting to feeding, the diel locomotor activity profile varied remarkably: a diurnal activity pattern at the bottom, while a clearly nocturnal pattern at the surface. These results contribute to a better understanding of feeding and locomotor rhythms of rainbow trout, providing evidence for the existence of a biological clock involved in their circadian control. This finding contrasts with the previously recorded lack of an endogenous oscillator in the pineal organ driving the rhythmic secretion of melatonin, which suggests different locations from the pineal for the circadian pacemakers in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1998.tb00797.x
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  • 4
    Electronic Resource
    Electronic Resource
    Individual rainbow trout can learn and anticipate multiple daily feeding times (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 61 (2002), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The present study was conducted to investigate whether individual rainbow trout Oncorhynchus mykiss can simultaneously anticipate two daily meals, and to evaluate the influence of time-restricted feeding schedules and light-dark (L:D) cycles on the timing of self-feeding activity. Individual rainbow trout were capable of anticipating not only a single meal but also two daily meals scheduled at different times; the duration of anticipation was short and precise. This seems to be the first convincing evidence to show that a single fish can simultaneously anticipate two daily meals. Change in the onset and cessation of light did not affect the duration of food-anticipatory activity, although it led to shift the phases of the light-related self-feeding activity. Moreover, under constant light and ad lib feeding conditions, only one band of rhythmic activity was observed in individual rainbow trout that had previously developed food-anticipatory activity to each of the two daily meals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2002.tb02486.x
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  • 5
    Electronic Resource
    Electronic Resource
    Immunostimulant effects of nucleotide isolated from yeast RNA on carp, Cyprinus carpio L. (2001)
    Oxford UK : Blackwell Science Ltd
    Journal of fish diseases 24 (2001), S. 0 
    Details
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Nucleotides from yeast RNA were evaluated for their ability to enhance the non-specific immune responses in carp, Cyprinus carpio. Oral administration of nucleotides to fish daily for 3 days resulted in enhanced responses of phagocytic and nitroblue tetrazolium (NBT) activities in kidney phagocytic cells. This activation of kidney cells was observed for at least 10 days post-treatment. The serum complement and lysozyme activities also increased in fish treated with nucleotides. Furthermore, the number of Aeromonas hydrophila in nucleotide-treated fish significantly decreased in the blood, kidney and liver after intraperitoneal injection. Thus yeast nucleotides appear to enhance non-specific immune responses in fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2761.2001.00314.x
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  • 6
    Electronic Resource
    Electronic Resource
    Feeding entrainment of locomotor activity rhythms in the goldfish is mediated by a feeding-entrainable circadian oscillator (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 121-132 
    Details
    ISSN: 1432-1351
    Keywords: Key words Locomotor activity ; Feeding-entrainment ; Circadian rhythms ; Vertical distribution ; Goldfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Periodic food availability can act as a potent zeitgeber capable of synchronizing many biological rhythms in fishes, including locomotor activity rhythms. In the present paper we investigated entrainment of locomotor rhythms to scheduled feeding under different light and feeding regimes. In experiment 1, fish were exposed to a 12:12 h light/dark cycle and fed one single daily meal in the middle of the light phase. In experiment 2, we tested the effect of random versus scheduled feeding on the daily distribution of activity. During random feeding, meals were randomly scheduled with intervals ranging from 12 to 36 h, while scheduled feeding consisted of one single daily meal set in the middle of the light or dark phase. Finally, in experiment 3, we studied the synchronization of activity rhythms to feeding under constant darkness (DD) and after shifting the feeding cycle by either advancing or delaying the feeding cycle by 9 h. The results revealed that goldfish synchronized to feeding, overcame light entrainment and significantly changed their daily distribution of activity according to their feeding schedule. In addition, the daily activity pattern modulated by feeding differed between layers: a peak of activity being noticeable directly after feeding at the bottom, while an anticipatory behaviour was obvious at the surface of the tank. Under DD and no food, free-running rhythms averaging 25.5 ± 1.9 h (mean ± SD) were detected. In conclusion, some properties of feeding entrainment (e.g. anticipation of the feeding time, free-running rhythms following termination of periodic feeding, and the stability of ø after shifting the feeding cycle) suggested that goldfish have (a) separate but tightly coupled light- and food-entrainable oscillators, or (b) a single oscillator that is entrainable by both light and food (one synchronizer being eventually stronger than the other).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050099
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  • 7
    Electronic Resource
    Electronic Resource
    Positron Trapping Defects in Neutron-Irradiated Vitreous and Crystalline SiO〈sub〉2〈/sub〉 (1997)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 255-257 (Sept. 1997), p. 460-462 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/02/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.255-257.460.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    Calbindin D28k-like immunoreactivity in the developing and regenerating circumvallate papilla of the rat (1997)
    Springer
    Cell & tissue research 291 (1997), S. 81-90 
    Details
    ISSN: 1432-0878
    Keywords: Key words Calbindin D28k ; Circumvallate papilla ; Taste buds ; Development ; Degeneration ; Regeneration ; Immunohistochemistry ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The distribution of calbindin D28k (CB)-like immunoreactivity (-LI) in the circumvallate papilla (CVP) was examined during development and regeneration following bilateral crush injury to the glossopharyngeal nerve in the rat. In the adult CVP, CB-like immunoreactive (-IR) nerve fibers were observed in the subgemmal region and some penetrated into the taste buds. CB-LI was also detected in the cytoplasm of the spindle-shaped gustatory cells in the lower half of the trench epithelium, which contained numerous synaptic vesicles and bundles of intermediate filaments. These CB-IR gustatory cells made synapse-like contacts with CB-IR nerve terminals. Some CB-IR nerve terminals made contacts with the gustatory cells negative for CB-LI. At least three developmental stages were defined with regard to the developmental changes in the distribution of CB-LI: (1) Stage I (embryonic day (E) 18–postnatal day (P)5): CB-IR nerve fibers appeared in the lamina propria just beneath the newly-formed CVP at E18, but the gustatory epithelium of the CVP contained no CB-IR structures. Taste buds with taste pores appeared at P1. (2) Stage II (P5–10): thin CB-IR nerve fibers began entering the trench epithelium, but no CB-IR cells were observed. (3) Stage III (P10–adult): in addition to the intragemmal and perigemmal CB-IR nerve fibers, very few CB-IR cells appeared in the taste buds around P10, and their numbers increased progressively. The changes in the distribution of taste buds and CB-LI following glossopharyngeal nerve injury were similar to those observed during development. On post-operative day (PO) 4, the taste buds and CB-IR cells decreased markedly in number. These CB-IR cells became round in shape, and the number of CB-IR nerve fibers decreased markedly. On PO8, both taste buds and CB-IR cells disappeared completely. The regenerated taste buds were first observed on PO12, increased rapidly in number by PO20, and increased slowly thereafter. CB-IR nerve fibers accumulated at the subgemmal region and began penetrating into the trench wall epithelium around PO16. CB-IR cells appeared between PO20 and PO24, and their numbers increased progressively and reached the normal level on PO40. The topographical localizations of the taste buds and CB-IR cells during development and regeneration were comparable to those of normal animals. The delay of the time courses for appearance of CB-IR nerve fibers and CB-IR cells compared to the appearance of taste buds during development and regeneration suggests that CB in the gustatory epithelium may participate in the survival of the taste bud cells rather than in the induction of the taste buds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050981
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  • 9
    Electronic Resource
    Electronic Resource
    Immunohistochemical localization of calbindin D28k during root formation of rat molar teeth (1999)
    Springer
    Cell & tissue research 297 (1999), S. 503-512 
    Details
    ISSN: 1432-0878
    Keywords: Key words Calbindin ; Hertwig’s epithelial root sheath ; Epithelial rest of Malassez ; Preodontoblast ; Periodontal fibroblast ; Immunohistochemistry ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The present study was undertaken to examine the localization of calbindin D28k (CB)-like immunoreactivity (-LI) during the root formation of the rat molar. In the adult rat, CB-LI was detected in some of the cells of the epithelial rest of Malassez at the bifurcational region and in certain cells between the root dentin and cementum at the apical region. These cells had indented nuclei and many tonofilaments, and cementocytes lacked CB-LI. Moreover, CB-LI was observed in the periodontal fibroblasts in the alveolar half of the apical region. During root formation, the cells in the Hertwig’s epithelial root sheath (HERS) lacked CB-LI, but most fragmented cells along the root surface began to express CB-LI when HERS was disrupted. Preodontoblasts and odontoblasts at the apical portion of the root also showed CB-LI. After the formation of cellular cementum, the CB-immunoreactive (-IR) cells were entrapped between the root dentin and cementum in the apical portion of the root. The number of CB-IR cells at the root surface decreased gradually, while that between the root dentin and cementum increased. The fibroblasts in the periodontal ligament began to express CB-LI after commencement of the occlusion, and the number and the staining intensity of CB-IR fibroblasts increased gradually with the passage of time. The present results suggest that CB may play an important role in the survival of the epithelial cells, in the cellular responses of periodontal fibroblasts against mechanical forces caused by the occlusion, and in the initial mineralization by the odontoblasts through the regulation of intracellular Ca2+ concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051377
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  • 10
    Electronic Resource
    Electronic Resource
    Daily cycles in plasma and ocular melatonin in demand-fed sea bass, Dicentrarchus labrax L. (1997)
    Springer
    Journal of comparative physiology 167 (1997), S. 409-415 
    Details
    ISSN: 1432-136X
    Keywords: Key words Melatonin ; Pineal ; Eye ; Feeding behaviour ; Daily rhythms ; Dual phasing ; Sea bass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Melatonin is regarded as an internal zeitgeber, involved in the synchronization to light of the daily and seasonal rhythms of vertebrates. To date, plasma and ocular melatonin in fish have been extensively surveyed almost solely in freshwater species – with the exception of some migrating species of salmonids. In the present paper, melatonin levels of a marine species (sea bass, Dicentrarchus labrax L) were examined. In addition, the daily rhythms of the demand-feeding activity of sea bass, a fish species characterized by a dual phasing capacity (i.e. the ability to switch between diurnal and nocturnal behaviour), were investigated before sampling. Sea bass, distributed in 12 groups of four fish and kept under constant water temperature and salinity, were exposed to a 12 h light:12 h dark cycle (200:0 lx, lights on at 0800 hours). After 4 weeks recording, the animals were killed at 0900, 1200, 1400, 1600, 1900, 2100, 2400, 0200, 0400, 0700 and 0900 hours. Actograms of demand-feeding records revealed a nocturnal feeding behaviour, with some cases of spontaneous inversions in phasing. Melatonin levels in plasma peaked in the middle of the dark phase, dropping after lights on. Melatonin in the eye, on the contrary, exhibited an inverse profile, with high levels during daytime and low levels at night. These results suggest that melatonin in the plasma and the eye may act independently on the flexible circadian system of sea bass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050090
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