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Yasuhiko Watari - One of the best experts on this subject based on the ideXlab platform.
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effects of background light conditions on thermoperiodic Eclosion rhythm of onion fly delia antiqua
Entomological Science, 2014Co-Authors: Yasuhiko Watari, Kazuhiro TanakaAbstract:To elucidate the effects of light on thermoperiodic regulation of adult Eclosion rhythm in the onion fly, Delia antiqua, the responses to two thermoperiods, 29°C (12 h):21°C (12 h) and 25.5°C (12 h):24.5°C (12 h), with different amplitude and same average temperature, were examined in continuous darkness (DD) and continuous light (LL). Irrespective of the temperature step between warm phase (W) and cool phase (C), temperature cycles effectively entrained the adult Eclosion rhythm in both DD and LL. Eclosion peaks, however, varied with light conditions and temperature step between W and C. It advanced by approximately 2–3 h in DD than in LL and at smaller temperature step. Background light conditions and temperature step also affect the amplitude of Eclosion rhythm. It became lower in LL than in DD and at smaller temperature steps. On transfer to constant temperature (25°C), Eclosion rhythm was elicited earliest in the pupae at 8°C temperature step in DD and latest in those at 1°C temperature step in LL. Pupae at 1°C temperature step in DD and at 8°C temperature step in LL demonstrated intermediate responses, but the Eclosion rhythm was elicited 1 day earlier in the former than in the latter. This might be ascribed to the interaction between background light and temperature step under thermoperiodic conditions. The results suggest that continuous light and a smaller temperature step weaken the coupling strength between Eclosion rhythm and thermoperiod, but the light effect is stronger than the temperature step effect.
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thermoperiodic regulation of the circadian Eclosion rhythm in the flesh fly sarcophaga crassipalpis
Journal of Insect Physiology, 2011Co-Authors: Yosuke Miyazaki, Kazuhiro Tanaka, Shin G Goto, Osamu Saito, Yasuhiko WatariAbstract:We recorded the Eclosion time of the flesh fly, Sarcophaga crassipalpis, at different depths in the outdoor soil and under temperature cycles with various amplitudes in the laboratory, to examine the timing adjustment of Eclosion in response to temperature cycles and their amplitudes in the pupal stage. In the soil, most Eclosions occurred in the late morning, which was consistent with the Eclosion time under pseudo-sinusoidal temperature cycles in the laboratory. The circadian clock controlling Eclosion was reset by temperature cycles and free-ran with a period close to 24h. This clock likely helps pupae eclose at an optimal time even when the soil temperature does not show clear daily fluctuations. The Eclosion phase of the circadian clock progressively advanced as the amplitude of the pseudo-sinusoidal temperature cycle decreased. This response allows pupae located at any depth in the soil to eclose at the appropriate time despite the depth-dependent phase delay of the temperature change. In contrast, the abrupt temperature increase in square-wave temperature cycles reset the phase of the circadian clock to the increasing time, regardless of the temperature amplitude. The rapid temperature increase may act as the late-morning signal for the Eclosion clock.
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interacting effect of thermoperiod and photoperiod on the Eclosion rhythm in the onion fly delia antiqua supports the two oscillator model
Journal of Insect Physiology, 2010Co-Authors: Yasuhiko Watari, Kazuhiro TanakaAbstract:Abstract Daily light and temperature cycles entrain adult Eclosion rhythms in many insect species, but little is known about their interaction. We studied this problem in the onion fly, Delia antiqua. Pupae were subjected to various combinations of a photoperiod of 12L:12D and thermoperiods. The thermoperiods consisted of 12 h warm phase (W) and 12 h cool phase (C), giving a mean temperature of 25 °C with different temperature steps of 8, 4 and 1 °C. As the phase relation of the two Zeitgebers was varied, the phase of Eclosion rhythm was shifted, depending on the phase angle with the light cycle and the amplitude of the temperature cycle. When the temperature step in the thermoperiod was 8 °C (WC 29:21 °C), the Eclosion rhythm was entrained mainly to thermoperiod rather than photoperiod. In the regime with a 4 °C temperature step (WC 27:23 °C), both thermoperiod and photoperiod affected Eclosion rhythm, and a phase jump of the Eclosion rhythm occurred when the warm phase of thermoperiod was delayed 15–18 h from light-on. In regimes with a 1 °C temperature step (WC 25.5:24.5 °C), the Eclosion rhythm was completely entrained to photoperiod. The observed interacting effect of light and temperature cycle on the Eclosion rhythm in D. antiqua can be explained by the two-oscillator model proposed by Pittendrigh and Bruce (1959) .
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comparison of the circadian Eclosion rhythm between non diapause and diapause pupae in the onion fly delia antiqua the change of rhythmicity
Journal of Insect Physiology, 2005Co-Authors: Yasuhiko WatariAbstract:Abstract When pupae of Delia antiqua were transferred to constant darkness (DD) from light–dark (LD) cycles or constant light (LL), the sensitivity to light of the circadian clock controlling Eclosion increased with age. The daily rhythm of Eclosion appeared in both non-diapause and diapause pupae only when this transfer was made during late pharate adult development. When transferred from LL to DD in the early pupal stage, the adult Eclosion was weakly rhythmic in non-diapause pupae but arrhythmic in diapause pupae. However, the sensitivity of the circadian clock to temperature cycles or steps was higher in diapause pupae than in non-diapause pupae; in the transfer to a constant 20 °C from a thermoperiod of 25 °C (12 h)/20 °C (12 h) on day 10 after pupation or from chilling (7.5 °C) in DD, the adult Eclosion from diapause pupae was rhythmic but that from non-diapause pupae arrhythmic. In a transfer to 20 °C from the thermoperiod after the initiation of Eclosion, rhythmicity was observed in both types of pupae. The larval stage was insensitive to the effect of LD cycle initiating the Eclosion rhythm. In D. antiqua pupae in the soil under natural conditions, therefore, the thermoperiod in the late pupal stage would be the most important ‘Zeitgeber’ for the determination of Eclosion timing.
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adult Eclosion timing of the onion fly delia antiqua in response to daily cycles of temperature at different soil depths
Naturwissenschaften, 2003Co-Authors: Kazuhiro Tanaka, Yasuhiko WatariAbstract:For insects pupating in the soil, the day/night temperature cycle may provide a primary time cue (Zeitgeber) for adult Eclosion to occur at an appropriate time of the day. In the soil, however, the phase of temperature cycle is delayed with depth because of the low heat conductivity of the soil. Therefore pupae located deeper in the soil may compensate for the depth-dependent phase delay of Zeitgeber to avoid mistimed emergence. We examined the adult Eclosion timing of the onion fly, Delia antiqua, pupating at different depths in soil and under various thermoperiods in the laboratory to determine if such compensation indeed occurs. We found that D. antiqua is able to compensate for the depth-dependent phase delay of the Zeitgeber by advancing the Eclosion timing in response to the amplitude of the temperature cycle decreasing with depth.
Norihisa Fujita - One of the best experts on this subject based on the ideXlab platform.
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Efficient folding of the insect neuropeptide Eclosion hormone by protein disulfide isomerase.
Journal of biochemistry, 2001Co-Authors: Norihisa Fujita, Masanori YoshidaAbstract:Eclosion hormone is an insect neuropeptide that consists of 62 amino acid residues including three disulfide bonds. We have previously reported its hypothetical 3D structure consisting mainly of three alpha-helices. In this paper, we report the effects of chaperone proteins on the refolding of denatured Eclosion hormone in a redox buffer containing reduced and oxidized glutathione. Urea-denatured Eclosion hormone was spontaneously reactivated within 1 min with a yield of more than 90%, while beta-mercaptoethanol-denatured Eclosion hormone was reactivated in a few minutes with a yield of 75%. Under the same experimental conditions, Eclosion hormone treated with beta-mercaptoethanol and urea was reactivated slowly with a yield of 47% over a period of 2 h. Protein disulfide isomerase, a eucaryotic chaperone protein, markedly increased the reactivation yield and rate of the totally denatured hormone. GroE oligomers slightly improved the reactivation yield but peptidyl prolyl isomerase had no influence on yield or rate. We propose that the folding pathway of Eclosion hormone involves at least two rate-limiting steps, and that protein disulfide isomerase is likely to be involved in the folding in insect neuronal cells.
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the functional residues and their representation by a hypothetical 3d model of silkworm Eclosion hormone
Protein Engineering, 1998Co-Authors: Norihisa Fujita, Takashi Maekawa, Satoshi Ohta, Takeshi KikuchiAbstract:1 To whom correspondence should be addressed We have previously reported that an insect neuropeptide, Eclosion hormone contained an a-helix in the N-terminal region and the helix was likely to play an important role in constructing an active globular structure. Furthermore, Met24 and Phe25 were found to be indispensable for the biological activity. On the other hand, no strict structure at the C-terminal side was found. In this paper, we predicted the secondary structure in the C-terminal side and analyzed the functional residues by a Gly-substitution technique. As a result, we speculated that the Eclosion hormone contains three a-helices throughout the molecule which are essential for an active peptide structure. Moreover, we found four residues important for the biological activity of silkworm Eclosion hormone: Phe29, Ile55, Phe58 and Leu59. In order to understand these results stereochemically, we have constructed a 3D structure using computer aided molecular modelling. The hypothetical 3D model showed that Phe25 and Phe58 interact together in a hydrophobic manner to keep a globular form. Met24, Phe29, and Ile55 are exposed to solvent to have a hydrophobic interaction with an Eclosion hormone receptor. Leu59 can also play an important role by forming a functional conformation with Phe29 and Ile55.
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prediction of the biologically active sites in Eclosion hormone from the silkworm bombyx mori
Protein Engineering, 1997Co-Authors: Takeshi Kikuchi, Michihiro Takai, Megumi Okamoto, Martin Geiser, Albert Schmitz, Keigo Gohda, Takeshi Morita, Kenichi Horii, Norihisa FujitaAbstract:The structure-activity relationship of Eclosion hormone from the silkworm, Bombyx mori, was analyzed. First, the probable active residues in silkworm Eclosion hormone and also tobacco hornworm Eclosion hormone were predicted by the average distance map method. To examine the contributions of those residues to the activity of silkworm Eclosion hormone, Gly-substituted mutants for those predicted residues were produced by site-directed mutagenesis and their activities were evaluated by a bioassay. Finally, Glu12, Met24 and Phe25 were estimated to be the crucial residues for the Eclosion hormone activity. The possibility of the development of a blocker of an Eclosion hormone receptor on the basis of the present work is also discussed.
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Eclosion hormone-mediated signal transduction in the silkworm abdominal ganglia: involvement of a cascade from inositol(1,4,5)trisphosphate to cyclic GMP.
Biochemical and biophysical research communications, 1994Co-Authors: Yasuhiko Shibanaka, Hideaki Hayashi, Michihiro Takai, Ichiro Umemura, Y. Fujisawa, M. Okamoto, Norihisa FujitaAbstract:The neuropeptide Eclosion hormone triggers ecdysis behavior in lepidopteran insects. We have previously shown that the Eclosion hormone stimulates the formation of two intracellular second messengers, cGMP and inositol(1,4,5)trisphosphate in the abdominal ganglia of Bombyx mori. In order to elucidate the intracellular signaling pathway involving these second messengers, we studied the Eclosion hormone-mediated signal transduction using saponin-treated abdominal ganglia.We obtained the following results; i) Eclosion hormone activated nitric oxide synthase, ii) the Eclosion hormone-induced cGMP increase was inhibited by various enzyme inhibitors such as NG-nitro-arginine; a nitric oxide synthase inhibitor, EGTA; a calcium chelating reagent, W-5; a calmodulin inhibitor and compound 48/80; a phospholipase C inhibitor and iii) the inositol(1,4,5)-trisphosphate stimulated the formation of cGMP, in the Bombyx abdominal ganglia. Based on these findings we tentatively propose a hypothetical pathway: The signal initially triggered by Eclosion hormone and Eclosion hormone receptor complex induces activation of phospholipase C which produces inositol(l,4,5)trisphosphate. Inositol(I,4,5)trisphosphate increases intracellular Ca2+, followed by subsequent activation of nitric oxide syrithase through the formation of Ca2+-calmodulin complex. The reaction product, nitric oxide acts on soluble guanylate cyclase to stimulate cGMP formation which induces the ecdysis behavior in Bombyx pharate adults.
Thomas H Q Powell - One of the best experts on this subject based on the ideXlab platform.
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standing geographic variation in Eclosion time and the genomics of host race formation in rhagoletis pomonella fruit flies
Ecology and Evolution, 2018Co-Authors: Meredith M Doellman, Scott P Egan, Gregory J Ragland, Peter J Meyers, Glen R Hood, Thomas H Q PowellAbstract:Taxa harboring high levels of standing variation may be more likely to adapt to rapid environmental shifts and experience ecological speciation. Here, we characterize geographic and host-related differentiation for 10,241 single nucleotide polymorphisms in Rhagoletis pomonella fruit flies to infer whether standing genetic variation in adult Eclosion time in the ancestral hawthorn (Crataegus spp.)-infesting host race, as opposed to new mutations, contributed substantially to its recent shift to earlier fruiting apple (Malus domestica). Allele frequency differences associated with early vs. late Eclosion time within each host race were significantly related to geographic genetic variation and host race differentiation across four sites, arrayed from north to south along a 430-km transect, where the host races co-occur in sympatry in the Midwest United States. Host fruiting phenology is clinal, with both apple and hawthorn trees fruiting earlier in the North and later in the South. Thus, we expected alleles associated with earlier Eclosion to be at higher frequencies in northern populations. This pattern was observed in the hawthorn race across all four populations; however, allele frequency patterns in the apple race were more complex. Despite the generally earlier Eclosion timing of apple flies and corresponding apple fruiting phenology, alleles on chromosomes 2 and 3 associated with earlier emergence were paradoxically at lower frequency in the apple than hawthorn host race across all four sympatric sites. However, loci on chromosome 1 did show higher frequencies of early Eclosion-associated alleles in the apple than hawthorn host race at the two southern sites, potentially accounting for their earlier Eclosion phenotype. Thus, although extensive clinal genetic variation in the ancestral hawthorn race exists and contributed to the host shift to apple, further study is needed to resolve details of how this standing variation was selected to generate earlier eclosing apple fly populations in the North.
Kazuhiro Tanaka - One of the best experts on this subject based on the ideXlab platform.
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effects of background light conditions on thermoperiodic Eclosion rhythm of onion fly delia antiqua
Entomological Science, 2014Co-Authors: Yasuhiko Watari, Kazuhiro TanakaAbstract:To elucidate the effects of light on thermoperiodic regulation of adult Eclosion rhythm in the onion fly, Delia antiqua, the responses to two thermoperiods, 29°C (12 h):21°C (12 h) and 25.5°C (12 h):24.5°C (12 h), with different amplitude and same average temperature, were examined in continuous darkness (DD) and continuous light (LL). Irrespective of the temperature step between warm phase (W) and cool phase (C), temperature cycles effectively entrained the adult Eclosion rhythm in both DD and LL. Eclosion peaks, however, varied with light conditions and temperature step between W and C. It advanced by approximately 2–3 h in DD than in LL and at smaller temperature step. Background light conditions and temperature step also affect the amplitude of Eclosion rhythm. It became lower in LL than in DD and at smaller temperature steps. On transfer to constant temperature (25°C), Eclosion rhythm was elicited earliest in the pupae at 8°C temperature step in DD and latest in those at 1°C temperature step in LL. Pupae at 1°C temperature step in DD and at 8°C temperature step in LL demonstrated intermediate responses, but the Eclosion rhythm was elicited 1 day earlier in the former than in the latter. This might be ascribed to the interaction between background light and temperature step under thermoperiodic conditions. The results suggest that continuous light and a smaller temperature step weaken the coupling strength between Eclosion rhythm and thermoperiod, but the light effect is stronger than the temperature step effect.
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thermoperiodic regulation of the circadian Eclosion rhythm in the flesh fly sarcophaga crassipalpis
Journal of Insect Physiology, 2011Co-Authors: Yosuke Miyazaki, Kazuhiro Tanaka, Shin G Goto, Osamu Saito, Yasuhiko WatariAbstract:We recorded the Eclosion time of the flesh fly, Sarcophaga crassipalpis, at different depths in the outdoor soil and under temperature cycles with various amplitudes in the laboratory, to examine the timing adjustment of Eclosion in response to temperature cycles and their amplitudes in the pupal stage. In the soil, most Eclosions occurred in the late morning, which was consistent with the Eclosion time under pseudo-sinusoidal temperature cycles in the laboratory. The circadian clock controlling Eclosion was reset by temperature cycles and free-ran with a period close to 24h. This clock likely helps pupae eclose at an optimal time even when the soil temperature does not show clear daily fluctuations. The Eclosion phase of the circadian clock progressively advanced as the amplitude of the pseudo-sinusoidal temperature cycle decreased. This response allows pupae located at any depth in the soil to eclose at the appropriate time despite the depth-dependent phase delay of the temperature change. In contrast, the abrupt temperature increase in square-wave temperature cycles reset the phase of the circadian clock to the increasing time, regardless of the temperature amplitude. The rapid temperature increase may act as the late-morning signal for the Eclosion clock.
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interacting effect of thermoperiod and photoperiod on the Eclosion rhythm in the onion fly delia antiqua supports the two oscillator model
Journal of Insect Physiology, 2010Co-Authors: Yasuhiko Watari, Kazuhiro TanakaAbstract:Abstract Daily light and temperature cycles entrain adult Eclosion rhythms in many insect species, but little is known about their interaction. We studied this problem in the onion fly, Delia antiqua. Pupae were subjected to various combinations of a photoperiod of 12L:12D and thermoperiods. The thermoperiods consisted of 12 h warm phase (W) and 12 h cool phase (C), giving a mean temperature of 25 °C with different temperature steps of 8, 4 and 1 °C. As the phase relation of the two Zeitgebers was varied, the phase of Eclosion rhythm was shifted, depending on the phase angle with the light cycle and the amplitude of the temperature cycle. When the temperature step in the thermoperiod was 8 °C (WC 29:21 °C), the Eclosion rhythm was entrained mainly to thermoperiod rather than photoperiod. In the regime with a 4 °C temperature step (WC 27:23 °C), both thermoperiod and photoperiod affected Eclosion rhythm, and a phase jump of the Eclosion rhythm occurred when the warm phase of thermoperiod was delayed 15–18 h from light-on. In regimes with a 1 °C temperature step (WC 25.5:24.5 °C), the Eclosion rhythm was completely entrained to photoperiod. The observed interacting effect of light and temperature cycle on the Eclosion rhythm in D. antiqua can be explained by the two-oscillator model proposed by Pittendrigh and Bruce (1959) .
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adult Eclosion timing of the onion fly delia antiqua in response to daily cycles of temperature at different soil depths
Naturwissenschaften, 2003Co-Authors: Kazuhiro Tanaka, Yasuhiko WatariAbstract:For insects pupating in the soil, the day/night temperature cycle may provide a primary time cue (Zeitgeber) for adult Eclosion to occur at an appropriate time of the day. In the soil, however, the phase of temperature cycle is delayed with depth because of the low heat conductivity of the soil. Therefore pupae located deeper in the soil may compensate for the depth-dependent phase delay of Zeitgeber to avoid mistimed emergence. We examined the adult Eclosion timing of the onion fly, Delia antiqua, pupating at different depths in soil and under various thermoperiods in the laboratory to determine if such compensation indeed occurs. We found that D. antiqua is able to compensate for the depth-dependent phase delay of the Zeitgeber by advancing the Eclosion timing in response to the amplitude of the temperature cycle decreasing with depth.
Yasuhiko Shibanaka - One of the best experts on this subject based on the ideXlab platform.
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Eclosion hormone-mediated signal transduction in the silkworm abdominal ganglia: involvement of a cascade from inositol(1,4,5)trisphosphate to cyclic GMP.
Biochemical and biophysical research communications, 1994Co-Authors: Yasuhiko Shibanaka, Hideaki Hayashi, Michihiro Takai, Ichiro Umemura, Y. Fujisawa, M. Okamoto, Norihisa FujitaAbstract:The neuropeptide Eclosion hormone triggers ecdysis behavior in lepidopteran insects. We have previously shown that the Eclosion hormone stimulates the formation of two intracellular second messengers, cGMP and inositol(1,4,5)trisphosphate in the abdominal ganglia of Bombyx mori. In order to elucidate the intracellular signaling pathway involving these second messengers, we studied the Eclosion hormone-mediated signal transduction using saponin-treated abdominal ganglia.We obtained the following results; i) Eclosion hormone activated nitric oxide synthase, ii) the Eclosion hormone-induced cGMP increase was inhibited by various enzyme inhibitors such as NG-nitro-arginine; a nitric oxide synthase inhibitor, EGTA; a calcium chelating reagent, W-5; a calmodulin inhibitor and compound 48/80; a phospholipase C inhibitor and iii) the inositol(1,4,5)-trisphosphate stimulated the formation of cGMP, in the Bombyx abdominal ganglia. Based on these findings we tentatively propose a hypothetical pathway: The signal initially triggered by Eclosion hormone and Eclosion hormone receptor complex induces activation of phospholipase C which produces inositol(l,4,5)trisphosphate. Inositol(I,4,5)trisphosphate increases intracellular Ca2+, followed by subsequent activation of nitric oxide syrithase through the formation of Ca2+-calmodulin complex. The reaction product, nitric oxide acts on soluble guanylate cyclase to stimulate cGMP formation which induces the ecdysis behavior in Bombyx pharate adults.
