PHOTORECEPTIONS IN THE ECLOSION OF THE SILKWORM, <i>Bombyx mort</i>

Shimizu, Isamu; Matsui, Kei

doi:10.1111/j.1751-1097.1983.tb04493.x

Cited by 21 publications

(16 citation statements)

References 14 publications

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“…2A). Probably the depletion had no effect on entrainment of the circadian oscillatory mechanism of the silkworm, as reported previously (Shimizu & Matsui 1983;Sakamoto & Shimizu, 1994). Even at the low illumination (10 lux) in LDs, the lutein-supplemented silkworm showed hatching patterns similar to those observed in the carotenoid-rich group at the high light intensity.…”

Section: Discussionsupporting

confidence: 66%

“…Previously (Shimizu & Matsui 1983;Sakamoto & Shimizu, 1994) and in the present study using the silkworm, it was found that carotenoid is not indispensable for the entrainment, formation and sustainment of circadian rhythms. This suggests that there is a circadian photoreceptive molecule other than carotenoid-or retinal-based pigments.…”

Section: Discussionmentioning

confidence: 72%

“…This light-on response is probably due to the masking or startle effect of abruptly turning light-on (Saunders, 1982). There is some evidence that eyes for visual organs mediate photoreception for masking in other insects (Truman, 1972(Truman, , 1974 and in the eclosion of the silkworm 66 K. Sakamoto et al (Shimizu & Matsui, 1983). Larval ocelli might be involved in this masking during hatching of the silkworm.…”

Section: Discussionmentioning

confidence: 96%

“…In LD cycles, insects normally show unimodal rhythm patterns but sometimes do bimodal patterns, depending on photoperiod (Saunders, 1982). Actually, Shimizu and Matsui (1983) demonstrated that both unimodal and bimodal patterns could be seen in the daily eclosion rhythm of the silkworm, and that in the bimodal eclosion rhythm one peak was endogenously controlled and the other was a masking or an exogenous effect of light-on. Therefore, we used several LD cycles to investigate the mechanism that regulates hatching rhythms of the silkworm.…”

Section: Discussionmentioning

confidence: 98%

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Effect of Carotenoid Depletion on the Hatching Rhythm of the Silkworm, Bombyx mori

Sakamoto¹,

Asai²,

Okada³

et al. 2003

Biological Rhythm Research

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To investigate the functional involvement of carotenoid in the insect circadian rhythm, we observed the effect of carotenoid depletion on the hatching patterns of the silkworm under several light conditions. When eggs were transferred from continuous light (LL) to continuous darkness (DD), an overt hatching rhythm was initiated. The first hatching peak, which was observed at 13.2 h after the transfer in the carotenoid-depleted silkworm, was reduced remarkably in both control groups (carotenoid-rich and carotenoid-depleted but with lutein supplementation), though subsequent peaks occurred with similar timing. Under LD 4 : 20, LD 12 : 12 and LD 20 : 4, hatching patterns depended on the dietary carotenoid and the light intensity of the photophase. At a low light intensity, carotenoid depletion suppressed hatching as a masking effect just after light-on. Under LD 4 : 20 at a low light illumination, hatchings in the carotenoid-depleted silkworm were observed during scotophase, but few larvae hatched during scotophase in the control groups. Our findings suggest that carotenoid is not indispensable for the photoreception, formation and entrainment of the circadian hatching rhythm, but that a carotenoid-dependent process that is induced by light-off and damps out in an hour-glass mode, suppresses the hatching during darkness without affecting the circadian oscillation. The possibility that this carotenoid-dependent process is involved in the photoperiodic induction in the silkworm was discussed.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 98%

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Effect of Carotenoid Depletion on the Hatching Rhythm of the Silkworm, Bombyx mori

Sakamoto¹,

Asai²,

Okada³

et al. 2003

Biological Rhythm Research

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“…2000). Some reports have described circadian rhythms of silkworm hatching and eclosion (Shimizu & Matsui 1983; Sakamoto & Shimizu 1994; Tanaka 1996). In addition, the peripheral tissues of adult silkworm moths appear to have daily rhythms (Iwai et al .…”

Section: Introductionmentioning

confidence: 99%

Photoreception in decapitated larvae of silkworm Bombyx mori

Nobata¹,

Oishi²,

Takeda³

et al. 2012

Entomological Science

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To investigate the photoreception that controls daily oscillations at the periphery in insects, we decapitated larvae of the silkworm Bombyx mori (Lepidoptera: Bombycidae) by ligature, and observed rhythms in their peripheral tissues under several light conditions. We measured the mRNA expression of period (per) and timeless (tim), which are homologues of Drosophila clock genes that function in the core oscillator of the circadian clock system. The expression of both per and tim significantly changed in the midgut, Malpighian tubules and silk glands of decapitated larvae exposed to photophase and scotophase that were reversed from the original daily light–dark cycle under which the larvae were housed. Under constant darkness, the daily expression of tim mRNA persisted for at least one cycle in the midgut and silk gland. In addition, an appropriate light stimulus under constant darkness induced a significant phase shift in the endogenous timing system (probably a circadian clock) that determined peak levels of tim mRNA expression in the midgut and silk glands of decapitated larvae. Since light regulated the gene expression rhythm in peripheral tissues of decapitated silkworm larvae, neither the brain nor eyes were essential for photoreception to control daily oscillations in these tissues. Thus, peripheral tissues in insects might directly use light even at the larval stage.

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Daily and Seasonal Rhythms

Underwood

Wassmer

Page

1997

Comprehensive Physiology

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The sections in this article are: Daily Rhythms Models and Mechanisms Circadian Pacemaking Systems in Invertebrates Pacemakers in the Arthropod Brain Circadian Pacemakers Outside the Nervous System in Insects Pacemakers in the Gastropod Retina Multioscillator Organization Identification of Output Pathways Circadian Pacemaking Systems in Vertebrates The Mammalian SCN Other Circadian Oscillators in Mammals Hypothalamic Regulation of Circadian Function in Nonmammalian Vertebrates The Pineal Organ Eyes as Clocks Photoreceptor Localization and Mechanisms of Entrainment in Invertebrates Photoreceptive Input: Invertebrates Mechanisms of Regulation of Pacemaker Phase Photoreceptor Localization and Mechanisms of Entrainment in Vertebrates Identification of Photoreceptors Mechanisms of Regulation of Pacemaker Phase Seasonality in Invertebrates Modes of Seasonality Timing of Seasonal Cycles Photoperiodic Time Measurement Mechanisms of Photoperiodic Time Measurement The Photoperiodic Timer The Photoperiodic Counter Anatomical Location of Timers and Counters Photoreceptors Circannual Rhythms Seasonality in Vertebrates Photoperiodic Time Measurement: Models and Experimental Validation Physiological Mechanisms The Pineal and Melatonin: Mammals Mechanisms of Pineal Action The Pineal and Melatonin: Nonmammalian Vertebrates Photoreceptive Inputs: Mammalian Photoreceptive Inputs: Nonmammalian Maternal–Fetal Transfer of Photoperiodic Information Circannual Rhythms Physiological Mechanisms Concluding Comments

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PHOTORECEPTIONS IN THE ECLOSION OF THE SILKWORM, Bombyx mort

Cited by 21 publications

References 14 publications

Effect of Carotenoid Depletion on the Hatching Rhythm of the Silkworm, Bombyx mori

Effect of Carotenoid Depletion on the Hatching Rhythm of the Silkworm, Bombyx mori

Photoreception in decapitated larvae of silkworm Bombyx mori

Daily and Seasonal Rhythms

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