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Hideharu Numata - One of the best experts on this subject based on the ideXlab platform.
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resetting of the Circannual Rhythm of the varied carpet beetle anthrenus verbasci by low temperature pulses
Physiological Entomology, 2016Co-Authors: Yosuke Miyazaki, Yasuhiko Watari, Hideharu NumataAbstract:The varied carpet beetle Anthrenus verbasci L. has a Circannual pupation Rhythm and pupates in the spring in the wild. The change in photoperiod acts as a predominant zeitgeber for this Rhythm. However, it is unclear whether the change in ambient temperature acts as a zeitgeber. The present study examines the effects of low-temperature pulses on this Circannual Rhythm by exposing larvae kept under constant short-day conditions (LD 12 : 12 h) at 20 °C to a lower temperature of 15, 10 or 5 °C for 8 or 12 weeks at various phases. Larval development and pupation are suppressed during exposure to low temperature, with this pupation being induced in sufficiently grown larvae within 2 months of a return to 20 °C. These results are attributed to the exogenous suppression and stimulation of pupation, rather than being related to the Circannual Rhythm (i.e. masking of the Circannual Rhythm by temperature). Furthermore, long-term observations demonstrate the existence of phase-dependent phase shifts of Circannual Rhythm as a result of low-temperature pulses. Circannual phase response curves to low temperature are constructed on the basis of the phase shifts obtained. A low-temperature pulse as a winter signal can reset the Circannual Rhythm of A. verbasci. It is probable that both temperature and photoperiod play a role in the entrainment of this Circannual Rhythm to a natural year.
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Resetting of the Circannual Rhythm of the varied carpet beetle Anthrenus verbasci by low‐temperature pulses
Physiological Entomology, 2016Co-Authors: Yosuke Miyazaki, Yasuhiko Watari, Hideharu NumataAbstract:The varied carpet beetle Anthrenus verbasci L. has a Circannual pupation Rhythm and pupates in the spring in the wild. The change in photoperiod acts as a predominant zeitgeber for this Rhythm. However, it is unclear whether the change in ambient temperature acts as a zeitgeber. The present study examines the effects of low-temperature pulses on this Circannual Rhythm by exposing larvae kept under constant short-day conditions (LD 12 : 12 h) at 20 °C to a lower temperature of 15, 10 or 5 °C for 8 or 12 weeks at various phases. Larval development and pupation are suppressed during exposure to low temperature, with this pupation being induced in sufficiently grown larvae within 2 months of a return to 20 °C. These results are attributed to the exogenous suppression and stimulation of pupation, rather than being related to the Circannual Rhythm (i.e. masking of the Circannual Rhythm by temperature). Furthermore, long-term observations demonstrate the existence of phase-dependent phase shifts of Circannual Rhythm as a result of low-temperature pulses. Circannual phase response curves to low temperature are constructed on the basis of the phase shifts obtained. A low-temperature pulse as a winter signal can reset the Circannual Rhythm of A. verbasci. It is probable that both temperature and photoperiod play a role in the entrainment of this Circannual Rhythm to a natural year.
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Circannual Rhythms in Insects
Annual Lunar and Tidal Clocks, 2014Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Although many insects adapt to seasonal changes by photoperiodism, a small proportion of insect species use a Circannual Rhythm for seasonal adaptations. The Circannual pupation Rhythm of the varied carpet beetle Anthrenus verbasci shows a periodicity of approximately 40 weeks under constant conditions, and the change in photoperiod acts as a zeitgeber. The Circannual Rhythm of A. verbasci, of which the larval duration varies from one to several years, probably plays an important role for synchronizing the pupation and breeding times with spring each year. There are only slight differences in the critical daylength for Circannual entrainment among geographically distinct populations in Japan, and they pupate in the same period under natural conditions in Osaka. Therefore, A. verbasci can adapt to seasonal changes in different regions without changing the parameters of the Circannual Rhythm. Long-term endogenous Rhythms have also been reported in oviposition and pupation of some ant species. These insects are considered to refer not only to external cues but also to the phase of an endogenous clock for maintaining appropriate seasonality.
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small geographic variation in photoperiodic entrainment of the Circannual Rhythm in the varied carpet beetle anthrenus verbasci
Zoological Science, 2013Co-Authors: Tomoya Matsuno, Yuta Kawasaki, Hideharu NumataAbstract:The Circannual pupation Rhythm of Anthrenus verbasci is entrained to an environmental cycle by changes in photoperiod. Exposure of larvae reared under short-day conditions to long days induced a clear phase delay of the Circannual Rhythm. There was no notable difference in the initial phase or period of the Circannual Rhythm among four geographically distinct populations of A. verbasci in Japan: Takanabe (32.1°N), Osaka (34.7°N), Sendai (38.3°N), and Sapporo (43.1°N) populations. The range of photoperiodic changes effective for phase delay in the Circannual pupation Rhythm was compared among the four populations. Although larvae did not show a typical threshold response, but responded quantitatively to the photophase duration in intermediate conditions, the critical daylengths were calculated as those under which the pupation was delayed by 50%: 12.8 h in the Takanabe population, 13.2 h in the Osaka population, and 13.6 h in the Sendai and Sapporo populations. Thus, the critical daylength for entrainment of the Circannual Rhythm in A. verbasci was correlated to the habitat latitude, but the differences among the populations were much smaller than those reported in photoperiodism for induction of diapause in various insects. Consequently, the difference in the pupation time among the four geographic populations was very small under the natural photoperiod in Osaka at 20°C, and absent under the natural photoperiod and temperature in Osaka. These results suggest that A. verbasci survives and successfully produces the next generation in different geographic regions without changing the parameters of the Circannual Rhythm.
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Circannual Rhythm in the varied carpet beetle anthrenus verbasci
Progress in Brain Research, 2012Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Although Circannual Rhythms controlling different physiological processes and various aspects of behavior have been reported in numerous organisms, our understanding of the underlying biological mechanisms is still quite limited. We examined the mechanisms controlling the Circannual pupation Rhythm of the varied carpet beetle, Anthrenus verbasci. This Rhythm is self-sustainable, exhibits temperature compensation of the periodicity, and is entrainable to environmental changes. In addition, the Circannual phase response curves to a photoperiod pulse display Type 0 or Type 1 resetting, depending on the duration of the pulse. Thus, we infer that this Rhythm is derived from a self-sustaining biological oscillator with a period of about a year, that is, a Circannual clock, analogous to the circadian clock. Further, a circadian clock appears to mediate photoperiodic time measurement for phase resetting of the Circannual clock. Based on these results and previous research performed in other organisms, we discuss the general characteristics of the physiological mechanisms underpinning Circannual Rhythmicity.
Catherine Viguié - One of the best experts on this subject based on the ideXlab platform.
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Changes in the 5-HT2_Areceptor system in the pre-mammillary hypothalamus of the ewe are related to regulation of LH pulsatile secretion by an endogenous Circannual Rhythm
BMC Neuroscience, 2003Co-Authors: Philippe Chemineau, Benoit Malpaux, Agnès Daveau, Jean Pelletier, Fred J Karsch, Catherine ViguiéAbstract:Background We wanted to determine if changes in the expression of serotonin 2A receptor (5HT2_A receptor) gene in the premammillary hypothalamus are associated with changes in reproductive neuroendocrine status. Thus, we compared 2 groups of ovariectomized-estradiol-treated ewes that expressed high vs low LH pulsatility in two different paradigms (2 groups per paradigm): (a) refractoriness (low LH secretion) or not (high LH secretion) to short days in pineal-intact Ile-de-France ewes (RSD) and (b) endogenous Circannual Rhythm (ECR) in free-running pinealectomized Suffolk ewes in the active or inactive stage of their reproductive Rhythm. Results In RSD ewes, density of 5HT2_A receptor mRNA (by in situ hybridization) was significantly higher in the high LH group (25.3 ± 1.4 vs 21.4 ± 1.5 grains/neuron, P < 0.05) and ^3H-Ketanserin binding (a specific radioligand) of the median part of the premammillary hypothalamus tended to be higher in the high group (29.1 ± 4.0 vs 24.6 ± 4.2 fmol/mg tissu-equivalent; P < 0.10). In ECR ewes, density of 5HT2_A receptor mRNA and ^3H-Ketanserin binding were both significantly higher in the high LH group (20.8 ± 1.6 vs 17.0 ± 1.5 grains/neuron, P < 0.01, and 19.7 ± 5.0 vs 7.4 ± 3.4 fmol/mg tissu-equivalent; P < 0.05, respectively). Conclusions We conclude that these higher 5HT2_A receptor gene expression and binding activity of 5HT2_A receptor in the premammillary hypothalamus are associated with stimulation of LH pulsatility expressed before the development of refractoriness to short days and prior to the decline of reproductive neuroendocrine activity during expression of the endogenous Circannual Rhythm.
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changes in the 5 ht2a receptor system in the pre mammillary hypothalamus of the ewe are related to regulation of lh pulsatile secretion by an endogenous Circannual Rhythm
BMC Neuroscience, 2003Co-Authors: Philippe Chemineau, Agnès Daveau, Jean Pelletier, Fred J Karsch, Catherine Viguié, B MalpauxAbstract:Background We wanted to determine if changes in the expression of serotonin 2A receptor (5HT2A receptor) gene in the premammillary hypothalamus are associated with changes in reproductive neuroendocrine status. Thus, we compared 2 groups of ovariectomized-estradiol-treated ewes that expressed high vs low LH pulsatility in two different paradigms (2 groups per paradigm): (a) refractoriness (low LH secretion) or not (high LH secretion) to short days in pineal-intact Ile-de-France ewes (RSD) and (b) endogenous Circannual Rhythm (ECR) in free-running pinealectomized Suffolk ewes in the active or inactive stage of their reproductive Rhythm.
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importance of photoperiodic signal quality to entrainment of the Circannual reproductive Rhythm of the ewe
Biology of Reproduction, 2000Co-Authors: G K Barrell, Catherine Viguié, L A Thrun, Martha E Brown, Fred J KarschAbstract:An endogenous Circannual Rhythm drives the seasonal reproductive cycle of a broad spectrum of species. This Rhythm is synchronized to the seasons (i.e., entrained) by photoperiod, which acts by regulating the circadian pattern of melatonin secretion from the pineal gland. Prior work has revealed that melatonin patterns secreted in spring/summer entrain the Circannual Rhythm of reproductive neuroendocrine activity in sheep, whereas secretions in winter do not. The goal of this study was to determine if inability of the winter-melatonin pattern to entrain the Rhythm is due to the specific melatonin pattern secreted in winter or to the stage of the Circannual Rhythm at that time of year. Either a summer- or a winter-melatonin pattern was infused for 70 days into pinealectomized ewes, centered around the summer solstice, when an effective stimulus readily entrains the Rhythm. The ewes were ovariectomized and treated with constant-release estradiol implants, and Circannual cycles of reproductive neuroendocrine activity were monitored by serum LH concentrations. Only the summer-melatonin pattern entrained the Circannual reproductive Rhythm. The inability of the winter pattern to do so indicates that the mere presence of a circadian melatonin pattern, in itself, is insufficient for entrainment. Rather, the characteristics of the melatonin pattern, in particular a pattern that mimics the photoperiodic signals of summer, determines entrainment of the Circannual Rhythm of reproductive neuroendocrine activity in the ewe.
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control of the Circannual Rhythm of reproduction by melatonin in the ewe
Brain Research Bulletin, 1997Co-Authors: Benoit Malpaux, Catherine Viguié, Donal C Skinner, Jeanclaude Thiery, P ChemineauAbstract:Annual variations in day length are responsible for seasonal changes in reproductive activity in sheep. However, in constant photoperiodic conditions, ewes express an endogenous Rhythm characterized by alternations of reproductive activity and quiescence that are not synchronized among animals. Thus, the main role of photoperiod in the natural environment appears to be the synchronization of this endogenous Rhythm. Photoperiodic information is processed through a complex nervous and endocrine pathway to modulate reproductive activity. Light information perceived at the level of the retina is transformed through neural processing into an endocrine signal by the pineal gland: the nocturnal increase in melatonin release. Recent studies strongly suggest that melatonin has a hypothalamic target to modulate the reproductive neuroendocrine axis. Most LHRH perikarya are located in the preoptic area, but this region is devoid of melatonin receptors, and microimplants of melatonin placed in the preoptic area do not effect LHRH release. Thus, melatonin influences LHRH neurones indirectly and must involve interneurons. Good evidence now exists to demonstrate that a population of dopaminergic neurons with axons projecting to the median eminence is one of these interneurons.
Yosuke Miyazaki - One of the best experts on this subject based on the ideXlab platform.
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resetting of the Circannual Rhythm of the varied carpet beetle anthrenus verbasci by low temperature pulses
Physiological Entomology, 2016Co-Authors: Yosuke Miyazaki, Yasuhiko Watari, Hideharu NumataAbstract:The varied carpet beetle Anthrenus verbasci L. has a Circannual pupation Rhythm and pupates in the spring in the wild. The change in photoperiod acts as a predominant zeitgeber for this Rhythm. However, it is unclear whether the change in ambient temperature acts as a zeitgeber. The present study examines the effects of low-temperature pulses on this Circannual Rhythm by exposing larvae kept under constant short-day conditions (LD 12 : 12 h) at 20 °C to a lower temperature of 15, 10 or 5 °C for 8 or 12 weeks at various phases. Larval development and pupation are suppressed during exposure to low temperature, with this pupation being induced in sufficiently grown larvae within 2 months of a return to 20 °C. These results are attributed to the exogenous suppression and stimulation of pupation, rather than being related to the Circannual Rhythm (i.e. masking of the Circannual Rhythm by temperature). Furthermore, long-term observations demonstrate the existence of phase-dependent phase shifts of Circannual Rhythm as a result of low-temperature pulses. Circannual phase response curves to low temperature are constructed on the basis of the phase shifts obtained. A low-temperature pulse as a winter signal can reset the Circannual Rhythm of A. verbasci. It is probable that both temperature and photoperiod play a role in the entrainment of this Circannual Rhythm to a natural year.
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Resetting of the Circannual Rhythm of the varied carpet beetle Anthrenus verbasci by low‐temperature pulses
Physiological Entomology, 2016Co-Authors: Yosuke Miyazaki, Yasuhiko Watari, Hideharu NumataAbstract:The varied carpet beetle Anthrenus verbasci L. has a Circannual pupation Rhythm and pupates in the spring in the wild. The change in photoperiod acts as a predominant zeitgeber for this Rhythm. However, it is unclear whether the change in ambient temperature acts as a zeitgeber. The present study examines the effects of low-temperature pulses on this Circannual Rhythm by exposing larvae kept under constant short-day conditions (LD 12 : 12 h) at 20 °C to a lower temperature of 15, 10 or 5 °C for 8 or 12 weeks at various phases. Larval development and pupation are suppressed during exposure to low temperature, with this pupation being induced in sufficiently grown larvae within 2 months of a return to 20 °C. These results are attributed to the exogenous suppression and stimulation of pupation, rather than being related to the Circannual Rhythm (i.e. masking of the Circannual Rhythm by temperature). Furthermore, long-term observations demonstrate the existence of phase-dependent phase shifts of Circannual Rhythm as a result of low-temperature pulses. Circannual phase response curves to low temperature are constructed on the basis of the phase shifts obtained. A low-temperature pulse as a winter signal can reset the Circannual Rhythm of A. verbasci. It is probable that both temperature and photoperiod play a role in the entrainment of this Circannual Rhythm to a natural year.
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Circannual Rhythms in Insects
Annual Lunar and Tidal Clocks, 2014Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Although many insects adapt to seasonal changes by photoperiodism, a small proportion of insect species use a Circannual Rhythm for seasonal adaptations. The Circannual pupation Rhythm of the varied carpet beetle Anthrenus verbasci shows a periodicity of approximately 40 weeks under constant conditions, and the change in photoperiod acts as a zeitgeber. The Circannual Rhythm of A. verbasci, of which the larval duration varies from one to several years, probably plays an important role for synchronizing the pupation and breeding times with spring each year. There are only slight differences in the critical daylength for Circannual entrainment among geographically distinct populations in Japan, and they pupate in the same period under natural conditions in Osaka. Therefore, A. verbasci can adapt to seasonal changes in different regions without changing the parameters of the Circannual Rhythm. Long-term endogenous Rhythms have also been reported in oviposition and pupation of some ant species. These insects are considered to refer not only to external cues but also to the phase of an endogenous clock for maintaining appropriate seasonality.
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Circannual Rhythm in the varied carpet beetle anthrenus verbasci
Progress in Brain Research, 2012Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Although Circannual Rhythms controlling different physiological processes and various aspects of behavior have been reported in numerous organisms, our understanding of the underlying biological mechanisms is still quite limited. We examined the mechanisms controlling the Circannual pupation Rhythm of the varied carpet beetle, Anthrenus verbasci. This Rhythm is self-sustainable, exhibits temperature compensation of the periodicity, and is entrainable to environmental changes. In addition, the Circannual phase response curves to a photoperiod pulse display Type 0 or Type 1 resetting, depending on the duration of the pulse. Thus, we infer that this Rhythm is derived from a self-sustaining biological oscillator with a period of about a year, that is, a Circannual clock, analogous to the circadian clock. Further, a circadian clock appears to mediate photoperiodic time measurement for phase resetting of the Circannual clock. Based on these results and previous research performed in other organisms, we discuss the general characteristics of the physiological mechanisms underpinning Circannual Rhythmicity.
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exhibition of Circannual Rhythm under constant light in the varied carpet beetle
Biological Rhythm Research, 2010Co-Authors: Yosuke Miyazaki, Hideharu NumataAbstract:The varied carpet beetle Anthrenus verbasci shows a clear Circannual pupation Rhythm under light/dark (LD) 12:12. We examined whether this Rhythm is exhibited under constant light (LL) of 0.002 Wm−2 and 0.9 Wm−2 intensities. Rhythmic pupation was not observed when the larvae were continuously maintained under LL. Moreover, the Circannual Rhythmicity of pupation was not observed under LL after pre-exposure to LD 12:12 for 2 or 4 weeks but was observed after exposure for 8 weeks. Under LL of both light intensities, as the pre-exposure to LD 12:12 was longer, the first pupation peaks occurred earlier and almost synchronized with pre-exposure for 8 weeks with the first peak under continuous LD 12:12. However, the transition from LD 12:12 to LL did not reset the phase of this Circannual Rhythm. Pre-exposure to LD 12:12 probably synchronizes the asynchronous Rhythm observed under LL so that a clear Circannual pupation Rhythm is exhibited.
Fred J Karsch - One of the best experts on this subject based on the ideXlab platform.
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Changes in the 5-HT2_Areceptor system in the pre-mammillary hypothalamus of the ewe are related to regulation of LH pulsatile secretion by an endogenous Circannual Rhythm
BMC Neuroscience, 2003Co-Authors: Philippe Chemineau, Benoit Malpaux, Agnès Daveau, Jean Pelletier, Fred J Karsch, Catherine ViguiéAbstract:Background We wanted to determine if changes in the expression of serotonin 2A receptor (5HT2_A receptor) gene in the premammillary hypothalamus are associated with changes in reproductive neuroendocrine status. Thus, we compared 2 groups of ovariectomized-estradiol-treated ewes that expressed high vs low LH pulsatility in two different paradigms (2 groups per paradigm): (a) refractoriness (low LH secretion) or not (high LH secretion) to short days in pineal-intact Ile-de-France ewes (RSD) and (b) endogenous Circannual Rhythm (ECR) in free-running pinealectomized Suffolk ewes in the active or inactive stage of their reproductive Rhythm. Results In RSD ewes, density of 5HT2_A receptor mRNA (by in situ hybridization) was significantly higher in the high LH group (25.3 ± 1.4 vs 21.4 ± 1.5 grains/neuron, P < 0.05) and ^3H-Ketanserin binding (a specific radioligand) of the median part of the premammillary hypothalamus tended to be higher in the high group (29.1 ± 4.0 vs 24.6 ± 4.2 fmol/mg tissu-equivalent; P < 0.10). In ECR ewes, density of 5HT2_A receptor mRNA and ^3H-Ketanserin binding were both significantly higher in the high LH group (20.8 ± 1.6 vs 17.0 ± 1.5 grains/neuron, P < 0.01, and 19.7 ± 5.0 vs 7.4 ± 3.4 fmol/mg tissu-equivalent; P < 0.05, respectively). Conclusions We conclude that these higher 5HT2_A receptor gene expression and binding activity of 5HT2_A receptor in the premammillary hypothalamus are associated with stimulation of LH pulsatility expressed before the development of refractoriness to short days and prior to the decline of reproductive neuroendocrine activity during expression of the endogenous Circannual Rhythm.
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changes in the 5 ht2a receptor system in the pre mammillary hypothalamus of the ewe are related to regulation of lh pulsatile secretion by an endogenous Circannual Rhythm
BMC Neuroscience, 2003Co-Authors: Philippe Chemineau, Agnès Daveau, Jean Pelletier, Fred J Karsch, Catherine Viguié, B MalpauxAbstract:Background We wanted to determine if changes in the expression of serotonin 2A receptor (5HT2A receptor) gene in the premammillary hypothalamus are associated with changes in reproductive neuroendocrine status. Thus, we compared 2 groups of ovariectomized-estradiol-treated ewes that expressed high vs low LH pulsatility in two different paradigms (2 groups per paradigm): (a) refractoriness (low LH secretion) or not (high LH secretion) to short days in pineal-intact Ile-de-France ewes (RSD) and (b) endogenous Circannual Rhythm (ECR) in free-running pinealectomized Suffolk ewes in the active or inactive stage of their reproductive Rhythm.
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importance of photoperiodic signal quality to entrainment of the Circannual reproductive Rhythm of the ewe
Biology of Reproduction, 2000Co-Authors: G K Barrell, Catherine Viguié, L A Thrun, Martha E Brown, Fred J KarschAbstract:An endogenous Circannual Rhythm drives the seasonal reproductive cycle of a broad spectrum of species. This Rhythm is synchronized to the seasons (i.e., entrained) by photoperiod, which acts by regulating the circadian pattern of melatonin secretion from the pineal gland. Prior work has revealed that melatonin patterns secreted in spring/summer entrain the Circannual Rhythm of reproductive neuroendocrine activity in sheep, whereas secretions in winter do not. The goal of this study was to determine if inability of the winter-melatonin pattern to entrain the Rhythm is due to the specific melatonin pattern secreted in winter or to the stage of the Circannual Rhythm at that time of year. Either a summer- or a winter-melatonin pattern was infused for 70 days into pinealectomized ewes, centered around the summer solstice, when an effective stimulus readily entrains the Rhythm. The ewes were ovariectomized and treated with constant-release estradiol implants, and Circannual cycles of reproductive neuroendocrine activity were monitored by serum LH concentrations. Only the summer-melatonin pattern entrained the Circannual reproductive Rhythm. The inability of the winter pattern to do so indicates that the mere presence of a circadian melatonin pattern, in itself, is insufficient for entrainment. Rather, the characteristics of the melatonin pattern, in particular a pattern that mimics the photoperiodic signals of summer, determines entrainment of the Circannual Rhythm of reproductive neuroendocrine activity in the ewe.
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photoperiodic synchronization of a Circannual reproductive Rhythm in sheep identification of season specific time cues
Biology of Reproduction, 1994Co-Authors: Celia J I Woodfill, Nancy L Wayne, Suzanne M Moenter, Fred J KarschAbstract:Seasonal reproduction in the ewe is generated by an endogenous Circannual Rhythm of reproductive neuroendocrine activity. Exposure to as few as 70 days of photoperiodic information a year is sufficient to synchronize the Rhythm. The present study was conducted to identify which portions of the photoperiodic cycle are utilized for synchronization. For this purpose, we used pinealectomized ewes that could not respond reproductively to changes in day length. Selected photoperiodic information was provided via infusion of melatonin, a hormone that provides the neuroendocrine code for day length in this species. Melatonin was delivered according to circadian patterns. The infusion patterns were tailored to mimic those of melatonin secretion in pineal-intact ewes during one of the four seasons: winter, spring, summer, or autumn
Tomoyosi Nisimura - One of the best experts on this subject based on the ideXlab platform.
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Circannual Rhythms in Insects
Annual Lunar and Tidal Clocks, 2014Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Although many insects adapt to seasonal changes by photoperiodism, a small proportion of insect species use a Circannual Rhythm for seasonal adaptations. The Circannual pupation Rhythm of the varied carpet beetle Anthrenus verbasci shows a periodicity of approximately 40 weeks under constant conditions, and the change in photoperiod acts as a zeitgeber. The Circannual Rhythm of A. verbasci, of which the larval duration varies from one to several years, probably plays an important role for synchronizing the pupation and breeding times with spring each year. There are only slight differences in the critical daylength for Circannual entrainment among geographically distinct populations in Japan, and they pupate in the same period under natural conditions in Osaka. Therefore, A. verbasci can adapt to seasonal changes in different regions without changing the parameters of the Circannual Rhythm. Long-term endogenous Rhythms have also been reported in oviposition and pupation of some ant species. These insects are considered to refer not only to external cues but also to the phase of an endogenous clock for maintaining appropriate seasonality.
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Circannual Rhythm in the varied carpet beetle anthrenus verbasci
Progress in Brain Research, 2012Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Although Circannual Rhythms controlling different physiological processes and various aspects of behavior have been reported in numerous organisms, our understanding of the underlying biological mechanisms is still quite limited. We examined the mechanisms controlling the Circannual pupation Rhythm of the varied carpet beetle, Anthrenus verbasci. This Rhythm is self-sustainable, exhibits temperature compensation of the periodicity, and is entrainable to environmental changes. In addition, the Circannual phase response curves to a photoperiod pulse display Type 0 or Type 1 resetting, depending on the duration of the pulse. Thus, we infer that this Rhythm is derived from a self-sustaining biological oscillator with a period of about a year, that is, a Circannual clock, analogous to the circadian clock. Further, a circadian clock appears to mediate photoperiodic time measurement for phase resetting of the Circannual clock. Based on these results and previous research performed in other organisms, we discuss the general characteristics of the physiological mechanisms underpinning Circannual Rhythmicity.
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Circannual pupation Rhythm in the varied carpet beetle anthrenus verbasci under different nutrient conditions
Entomological Science, 2009Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Anthrenus verbasci pupates in spring and the timing of pupation is controlled by a Circannual Rhythm. Although A. verbasci is considered to be a univoltine species in Japan, it is assumed that larval development in its natural habitats, including bird nests, varies with nutrient availability, and that the life cycle often takes two or more years to complete. In the present study, larval development and pupation times were compared under constant and outdoor conditions in larvae provided a diet of either high-nutrient bonito powder or low-nutrient pigeon feathers. Although a Circannual pupation Rhythm was observed irrespective of the diet used, larval development was slower on feathers than on bonito powder. The pupation times on feathers varied over three years or more under both constant and outdoor conditions. Under outdoor conditions, larvae grown on feathers needed three years to approach the weight gained within a year by larvae grown on bonito powder. It is considered that life cycle length in A. verbasci is often two years or more in nutritionally unstable natural habitats, and that this species has probably evolved a Circannual Rhythm as a seasonal adaptation to nutrient-poor environments.
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a circadian system is involved in photoperiodic entrainment of the Circannual Rhythm of anthrenus verbasci
Journal of Insect Physiology, 2009Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Abstract In the Circannual pupation Rhythm of the varied carpet beetle, Anthrenus verbasci, entrainment to annual cycles is achieved by phase resetting of the Circannual oscillator in response to photoperiodic changes. In order to examine whether a circadian system is involved in expression of the periodic pattern and phase resetting of the Circannual Rhythm as photoperiodic responses, we exposed larvae to light–dark cycles with a short photophase followed by a variable scotophase (the Nanda–Hamner protocol). When the cycle length (T) was a multiple of 24 h, i.e., 24, 48, or 72 h, short-day effects were clearer than when T was far from a multiple of 24 h, i.e., 36 or 60 h. Exposure to light–dark cycles of T = 36 h had effects similar to exposure to long-day cycles of T = 24 h. The magnitude of phase shifts depended on the duration and the phase of exposure to the cycles of T = 36 or 60 h. It was therefore concluded that a circadian system is involved in photoperiodic time measurement for phase resetting of the Circannual oscillator of A. verbasci.
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phase responses in the Circannual Rhythm of the varied carpet beetle anthrenus verbasci under naturally changing day length
Zoological Science, 2006Co-Authors: Yosuke Miyazaki, Tomoyosi Nisimura, Hideharu NumataAbstract:Abstract In the varied carpet beetle, Anthrenus verbasci, we examined the effects on the Circannual pupation Rhythm of a short-day or long-day pulse under naturally changing day length at a constant 20°C. A short-day pulse for 4 weeks caused a prominent phase delay or advance under constant long days, but had little or no effect on the phase under naturally changing day length between 4 August and 24 November. A long-day pulse for 4 weeks given under naturally changing day length caused a phase shift in the first pupation group, as under constant short days. A long-day pulse given on 4 August, 1 September, or 29 September caused a phase delay, and a pulse given on 27 October or 24 November caused a phase advance. Pupation was least synchronous just before the transition from delaying to advancing. However, the magnitude of phase delays was much smaller under natural day length than under short days. In the second pupation group, larvae pupated at the same time as in the control experiment without a long-d...