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Journal articles on the topic 'Free-running rhythm'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

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1

Kennaway, D. J., and C. F. Van Dorp. "Free-running rhythms of melatonin, cortisol, electrolytes, and sleep in humans in Antarctica." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 260, no. 6 (June 1, 1991): R1137—R1144. http://dx.doi.org/10.1152/ajpregu.1991.260.6.r1137.

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The geographic isolation and the prolonged absence of sunlight during winter make Antarctica an interesting environment for studying circadian rhythms. This study explored the effects of wintering on sleep, hormonal, and electrolyte rhythms in four human subjects living in a small Antarctic base. Up to the last sunset sleep, 6-sulfatoxymelatonin, cortisol, sodium, and potassium rhythms were synchronized within clock time. During the 126 days of winter, when there was no sunlight, the circadian rhythms of all measures free ran in each individual. For example, the free-running periods for the co

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2

Sailaja, B., and S. Sivaprasad. "Photoperiod-induced clock-shifting in the circadian protein and amino acid rhythms in the larval fat body of silkworm, Bombyx mori." Journal of Applied and Natural Science 3, no. 1 (June 1, 2011): 38–50. http://dx.doi.org/10.31018/jans.v3i1.151.

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The photoperiod-induced clock-shifting in the free running time of the circadian protein and amino acid rhythms was studied in the larval fat body of Bombyx mori. The analysis of peaks and troughs of phase response curves of the rhythm revealed that the fourth and fifth instar larvae grown under normal 12 h light and 12 h dark cycle (LD) showed 7 protein synthetic cycles, while those reared under continuous light (LL) recorded 9.5 cycles in fourth instar and 8 in fifth instar. Under continuous dark (DD), the protein rhythm maintained 8 cycles in fourth instar and 7.5 cycles in fifth instar. Cl

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3

Jilge, B., H. Hornicke, and H. Stahle. "Circadian rhythms of rabbits during restrictive feeding." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 253, no. 1 (July 1, 1987): R46—R54. http://dx.doi.org/10.1152/ajpregu.1987.253.1.r46.

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Without a zeitgeber the circadian rhythms of five physiological functions free-ran with a period length greater than 24 h. Restricted feeding time (RF) masked the free-running rhythms. In addition to masking, entrainment with RF occurred. This process was most evident in locomotor activity and visits to the food box. RF thus had zeitgeber properties in these rabbits. However, in most rabbits the RF zeitgeber was not strong enough to entrain the circadian rhythm completely. A small component free-ran during RF. Following return to continuous food access the whole circadian rhythm resumed to fre

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4

Abe, Masato S., Kentarou Matsumura, Taishi Yoshii, and Takahisa Miyatake. "Amplitude of circadian rhythms becomes weaken in the north, but there is no cline in the period of rhythm in a beetle." PLOS ONE 16, no. 1 (January 14, 2021): e0245115. http://dx.doi.org/10.1371/journal.pone.0245115.

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Many species show rhythmicity in activity, from the timing of flowering in plants to that of foraging behavior in animals. The free-running periods and amplitude (sometimes called strength or power) of circadian rhythms are often used as indicators of biological clocks. Many reports have shown that these traits are highly geographically variable, and interestingly, they often show latitudinal or longitudinal clines. In many cases, the higher the latitude is, the longer the free-running circadian period (i.e., period of rhythm) in insects and plants. However, reports of positive correlations be

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5

Dushay, M. S., R. J. Konopka, D. Orr, M. L. Greenacre, C. P. Kyriacou, M. Rosbash, and J. C. Hall. "Phenotypic and genetic analysis of Clock, a new circadian rhythm mutant in Drosophila melanogaster." Genetics 125, no. 3 (July 1, 1990): 557–78. http://dx.doi.org/10.1093/genetics/125.3.557.

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Abstract Clock is a semidominant X-linked mutation that results in shortening the period of Drosophila melanogaster's free-running locomotor activity rhythm from ca. 24.0 to ca. 22.5 hr. This mutation similarly shortened the phase response curve, determined by resetting activity rhythms with light pulses. Eclosion peaks for Clk cultures were separated by only 22.5 hr instead of the normal 24 hr. Clk was mapped close to, but separable from, another rhythm mutation--period01--by recombination. The estimated distance between these two mutations was short enough to suggest that Clk could be a per

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6

Heynick, Frank. "A geophysical note on man's free‐running circadian rhythm." Journal of Interdisiplinary Cycle Research 17, no. 2 (July 1986): 113–19. http://dx.doi.org/10.1080/09291018609359903.

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7

Yamada, Naoto, Kazutaka Shimoda, Ken Ohi, Saburo Takahashi, and Kiyohisa Takahashi. "Free-access to a running wheel shortens the period of free-running rhythm in blinded rats." Physiology & Behavior 42, no. 1 (January 1988): 87–91. http://dx.doi.org/10.1016/0031-9384(88)90265-x.

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8

Davis, Fred C., and N. Viswanathan. "Stability of circadian timing with age in Syrian hamsters." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, no. 4 (October 1, 1998): R960—R968. http://dx.doi.org/10.1152/ajpregu.1998.275.4.r960.

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The causes of age-related disruptions in the timing of human sleep and wakefulness are not known but may include changes in both the homeostatic and circadian regulation of sleep. In Syrian hamsters the free running period of the circadian activity/rest rhythm has been reported to shorten with age. Although this has been observed under a variety of experimental conditions, the changes have been small and their consistency uncertain. In the present study, the wheel running activity/rest rhythm was continuously measured in male Syrian hamsters ( Mesocricetus auratus) in dim constant light (<1

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9

Wolff, Gretchen, Marilyn J. Duncan, and Karyn A. Esser. "Chronic phase advance alters circadian physiological rhythms and peripheral molecular clocks." Journal of Applied Physiology 115, no. 3 (August 1, 2013): 373–82. http://dx.doi.org/10.1152/japplphysiol.01139.2012.

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Shifting the onset of light, acutely or chronically, can profoundly affect responses to infection, tumor progression, development of metabolic disease, and mortality in mammals. To date, the majority of phase-shifting studies have focused on acute exposure to a shift in the timing of the light cycle, whereas the consequences of chronic phase shifts alone on molecular rhythms in peripheral tissues such as skeletal muscle have not been studied. In this study, we tested the effect of chronic phase advance on the molecular clock mechanism in two phenotypically different skeletal muscles. The phase

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10

Underwood, H., T. Siopes, and K. Edmonds. "Eye and gonad: role in the dual-oscillator circadian system of female Japanese quail." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 272, no. 1 (January 1, 1997): R172—R182. http://dx.doi.org/10.1152/ajpregu.1997.272.1.r172.

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Experiments were conducted to determine the anatomic and physiological basis of the dual-oscillator circadian system of female Japanese quail. After blocking of ocular light perception by eye-patching, the circadian body temperature rhythm dissociates into two circadian components in continuous lighting (LL). One component free runs with a period significantly shorter than 24 h [mean period (tau) = 22.7 h] and is driven by an ocular pacemaker, whereas the other component free runs with a period significantly longer than 24 h (tau = 26.3 h). The long free-running rhythm is driven by the same ci

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11

Reid, D. G., and E. Naylor. "Free-Running, Endogenous Semilunar Rhythmicity in a Marine Isopod Crustacean." Journal of the Marine Biological Association of the United Kingdom 65, no. 1 (February 1985): 85–91. http://dx.doi.org/10.1017/s0025315400060823.

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In recent years several workers have postulated the occurrence in a number of coastal animals of endogenous behaviour and physiological rhythms of semilunar periodicity (see Naylor, 1982). However, only a few of these long term rhythms have been demonstrated as free-running cyclical behaviour over long periods of time in constant conditions. For example, the supra-littoral amphipod Talitrus saltator (Montagu) has been shown to express semilunar variations in daily locomotor activity over three cycles of neap/spring tides during 46 days in constant conditions in the laboratory (Williams, 1979).

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12

Edgar, D. M., and W. C. Dement. "Regularly scheduled voluntary exercise synchronizes the mouse circadian clock." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 261, no. 4 (October 1, 1991): R928—R933. http://dx.doi.org/10.1152/ajpregu.1991.261.4.r928.

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Circadian rhythm entrainment has long been thought to depend exclusively on periodic cues in the external environment. However, evidence now suggests that appropriately timed vigorous activity may also phase shift the circadian clock. Previously it was not known whether levels of exercise/activity associated with spontaneous behavior provided sufficient feedback to phase shift or synchronize circadian rhythms. The present study investigated this issue by monitoring the sleep-wake, drinking, and wheel-running circadian rhythms of mice (Mus musculus) during unrestricted access to running wheels

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13

Thomas, E. M., and S. M. Armstrong. "Effect of ovariectomy and estradiol on unity of female rat circadian rhythms." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 257, no. 5 (November 1, 1989): R1241—R1250. http://dx.doi.org/10.1152/ajpregu.1989.257.5.r1241.

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Sixteen rats were ovariectomized and given either a 1-cm implant of crystalline estradiol-17 beta (eight rats) or an empty implant (eight rats). A further six rats were sham ovariectomized and given empty implants, and eight rats were left unoperated. The rats were exposed to 70 days of constant dim light (LL) with a maximum illumination level of 20 lx, and circadian running and drinking rhythms were monitored. In LL, both the running and drinking activity rhythms of the ovariectomized, blank-implanted rats became markedly disrupted, whereas unoperated and sham-operated rats maintained unified

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14

Cambras, Trinitat, John R. Weller, Montserrat Anglès-Pujoràs, Michael L. Lee, Andrea Christopher, Antoni Díez-Noguera, James M. Krueger, and Horacio O. de la Iglesia. "Circadian desynchronization of core body temperature and sleep stages in the rat." Proceedings of the National Academy of Sciences 104, no. 18 (April 23, 2007): 7634–39. http://dx.doi.org/10.1073/pnas.0702424104.

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Proper functioning of the human circadian timing system is crucial to physical and mental health. Much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. We have developed an animal model of human internal desynchrony in which rats are exposed to artificially short (22-h) light–dark cycles. Under these conditions, locomotor activity, sleep–wake, and slow-wave sleep (SWS) exhibit two rhythms wit

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15

Robinson, Edward L., and Charles A. Fuller. "Endogenous thermoregulatory rhythms of squirrel monkeys in thermoneutrality and cold." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, no. 5 (May 1, 1999): R1397—R1407. http://dx.doi.org/10.1152/ajpregu.1999.276.5.r1397.

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Whole body heat production (HP) and heat loss (HL) were examined to determine if the free-running circadian rhythm in body temperature (Tb) results from coordinated changes in HP and HL rhythms in thermoneutrality (27°C) as well as mild cold (17°C). Squirrel monkey metabolism ( n = 6) was monitored by both indirect and direct calorimetry, with telemetered measurement of Tb and activity. Feeding was also measured. Rhythms of HP, HL, and conductance were tightly coupled with the circadian Tb rhythm at both ambient temperatures (TA). At 17°C, increased HP compensated for higher HL at all phases o

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16

Sailaja, B., and S. Sivaprasad. "Photoperiodic modulation of circadian rhythms in the silk gland protein profiles of Bombyx mori and its influence on the silk productivity and quality." Journal of Applied and Natural Science 2, no. 1 (June 1, 2010): 48–56. http://dx.doi.org/10.31018/jans.v2i1.94.

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Circadian rhythms in the silk gland protein profiles of Bombyx mori were analyzed under 12 h light and 12 h dark cycle (LD), continuous light (LL) and continuous dark (DD) conditions. The phase response curves of protein rhythms indicate the prevalence of a series of silk cycles, each comprising three phases; transcription, translation and consolidation of silk proteins. In the 24h- protein rhythm, the silk cycle repeats every 3h, 42 m under LD, 2h, 36m under LL and 3h under DD. The light and dark conditions advanced the rhythm of each silk cycle by 48m and 24m respectively. As a result the si

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17

Wenger, D., H. Biebach, and J. R. Krebs. "Free-running circadian rhythm of a learned feeding pattern in starlings." Naturwissenschaften 78, no. 2 (February 1991): 87–89. http://dx.doi.org/10.1007/bf01206266.

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18

Paolucci, Silvia, Elena Dalla Benetta, Lucia Salis, David Doležel, Louis van de Zande, and Leo Beukeboom. "Latitudinal Variation in Circadian Rhythmicity in Nasonia vitripennis." Behavioral Sciences 9, no. 11 (November 15, 2019): 115. http://dx.doi.org/10.3390/bs9110115.

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Many physiological processes of living organisms show circadian rhythms, governed by an endogenous clock. This clock has a genetic basis and is entrained by external cues, such as light and temperature. Other physiological processes exhibit seasonal rhythms, that are also responsive to light and temperature. We previously reported a natural latitudinal cline of photoperiodic diapause induction in the parasitic wasp Nasonia vitripennis in Europe and a correlated haplotype frequency for the circadian clock gene period (per). To evaluate if this correlation is reflected in circadian behaviour, we

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19

Wang, Danfeng, Guang Yang, and Wenfeng Chen. "Diel and Circadian Patterns of Locomotor Activity in the Adults of Diamondback Moth (Plutella xylostella)." Insects 12, no. 8 (August 14, 2021): 727. http://dx.doi.org/10.3390/insects12080727.

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The Diamondback Moth (Plutella xylostella) is a highly destructive lepidopteran pest of cruciferous crops. However, there still is relatively little known about the locomotor activities of diel and the circadian patterns in P. xylostella. Here, we present an analysis of the diel locomotion of P. xylostella under several laboratory settings. We established a system for measuring the individual locomotor activities of P. xylostella and found that both males and females showed a nocturnal pattern of activity under 26 or 20 °C LD conditions, with activity peaking immediately after lights off and q

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20

Yamanaka, Yujiro, Sato Honma, and Ken-ichi Honma. "Daily exposure to a running wheel entrains circadian rhythms in mice in parallel with development of an increase in spontaneous movement prior to running-wheel access." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 305, no. 11 (December 1, 2013): R1367—R1375. http://dx.doi.org/10.1152/ajpregu.00389.2013.

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Entrainment of circadian behavior rhythms by daily exposure to a running wheel was examined in mice under constant darkness. Spontaneous movement was individually monitored for more than 6 mo by a thermal sensor. After establishment of steady-state free running, mice were placed in a different cage equipped with a running-wheel for 3 h once per day at 6 AM. The daily exchange was continued for 80 days. The number of wheel revolutions during exposure to the running wheel was also measured simultaneously with spontaneous movement. In 13 out of 17 mice, circadian behavior rhythm was entrained by

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21

Kuroda, H. "Daily Wheel Running Activity Modifies the Period of Free-Running Rhythm in Rats Via Intergeniculate Leaflet." Physiology & Behavior 61, no. 5 (May 1997): 633–37. http://dx.doi.org/10.1016/s0031-9384(96)00457-x.

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22

Wollnik, F., and F. W. Turek. "SCN lesions abolish ultradian and circadian components of activity rhythms in LEW/Ztm rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 256, no. 5 (May 1, 1989): R1027—R1039. http://dx.doi.org/10.1152/ajpregu.1989.256.5.r1027.

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A trimodal locomotor activity pattern has been observed in LEW/Ztm rats. Complete and partial lesions of the suprachiasmatic nucleus (SCN) were used to determine whether the same neural substrate may underlie the circadian rhythms and the ultradian modulation of wheel-running activity in these rats. Whereas sham lesions had little or no effect on the wheel-running activity pattern, complete SCN lesions resulted in a complete loss of circadian and ultradian activity components under free-running or 12:12 h light-dark cycle (12:12 LD) conditions. Ultradian and circadian activity components were

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23

Hill, Elizabeth Anne. "Free-running circadian rhythm disorder in the sighted – case report & discussion." Res Medica 21, no. 1 (September 30, 2013): 50. http://dx.doi.org/10.2218/resmedica.v21i1.174.

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Tsujimaru, Shusaku, Hideaki Egami, Goro Honma, Yoshishige Ida, Hirotaka Mukasa, and Yoichi Nakazawa. "Effects of Vitamin B12on the Period of Free-Running Rhythm in Rats." Psychiatry and Clinical Neurosciences 46, no. 1 (March 1992): 225–26. http://dx.doi.org/10.1111/j.1440-1819.1992.tb00843.x.

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Kyorku, Charles, and John Brady. "A free-running bimodal circadian rhythm in the tsetse fly Glossina longipennis." Journal of Insect Physiology 40, no. 1 (January 1994): 63–67. http://dx.doi.org/10.1016/0022-1910(94)90112-0.

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26

Northcott, S. J., R. N. Gibson, and E. Morgan. "The persistence and modulation of endogenous circatidal rhythmicity in Lipophrys pholis (Teleostei)." Journal of the Marine Biological Association of the United Kingdom 70, no. 4 (November 1990): 815–27. http://dx.doi.org/10.1017/s0025315400059087.

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In constant conditions, freshly-collected Lipophrys pholis show an endogenous circatidal activity rhythm, the initial activity peaks of which are phased to the expected time of high tide. The rhythm usually damps out over a few days but it may re-appear spontaneously or as a result of disturbance caused by handling and transfer to the experimental apparatus. The free-running period is more variable in fish kept in non-tidal conditions for prolonged periods than in those recorded shortly after capture. The non-circatidal periodicity shown by some fish may be the result of stable coupling in ant

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Abe, H., and B. Rusak. "Anticipatory activity and entrainment of circadian rhythms in Syrian hamsters exposed to restricted palatable diets." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 263, no. 1 (July 1, 1992): R116—R124. http://dx.doi.org/10.1152/ajpregu.1992.263.1.r116.

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Activity rhythms were recorded from hamsters in three conditions: during timed feedings of an attractive diet with free access to regular food, during restriction to 70% of normal food consumption, and during moderate food deprivation with limited temporal access to an attractive diet. An attractive diet given to intact animals did not induce anticipatory activity or entrainment, but damage to the suprachiasmatic nuclei (SCN) led to the development of anticipatory activity. Food restriction to 70% of normal intake led to anticipatory components in some intact animals, without entraining the do

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Matsumura, Kentarou, Masato S. Abe, Manmohan D. Sharma, David J. Hosken, Taishi Yoshii, and Takahisa Miyatake. "Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae)." Biological Journal of the Linnean Society 130, no. 1 (March 7, 2020): 34–40. http://dx.doi.org/10.1093/biolinnean/blaa016.

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Abstract Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effe

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Tran, Damien, Mickael Perrigault, Pierre Ciret, and Laura Payton. "Bivalve mollusc circadian clock genes can run at tidal frequency." Proceedings of the Royal Society B: Biological Sciences 287, no. 1918 (January 8, 2020): 20192440. http://dx.doi.org/10.1098/rspb.2019.2440.

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Marine coastal habitats are complex cyclic environments as a result of sun and moon interactions. In contrast with the well-known circadian orchestration of the terrestrial animal rhythmicity (approx. 24 h), the mechanism responsible for the circatidal rhythm (approx. 12.4 h) remains largely elusive in marine organisms. We revealed in subtidal field conditions that the oyster Crassostrea gigas exhibits tidal rhythmicity of circadian clock genes and clock-associated genes. A free-running (FR) experiment showed an endogenous circatidal rhythm. In parallel, we showed in the field that oysters' va

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Abelló, P., D. G. Reid, and E. Naylor. "Comparative locomotor activity patterns in the portunid crabs Liocarcinus holsatus and L. depurator." Journal of the Marine Biological Association of the United Kingdom 71, no. 1 (February 1991): 1–10. http://dx.doi.org/10.1017/s0025315400037346.

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The free-running locomotor activity rhythms of freshly-captured swimming crabs Liocarcinus holsatus and L. depurator have been studied in constant conditions in the laboratory. L. holsatus captured in the intertidal zone of sandy beaches showed strong circatidal activity rhythms with maximum activity at high tide. L. holsatus captured in the sublittoral zone had a clear tendency to show circadian activity rhythms with highest activity during day-time hours. L. depurator occurred only sublittorally and showed circadian activity patterns with highest activity during the night. Exposure to hydros

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Poulis, J. A., F. Roelfsema, and D. van der Heide. "Circadian urinary excretion rhythms in adrenalectomized rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 251, no. 3 (September 1, 1986): R441—R449. http://dx.doi.org/10.1152/ajpregu.1986.251.3.r441.

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The impact of the adrenal system on urinary rhythms was investigated in adrenalectomized (ADX) rats under various experimental conditions. During a 12:12 light-dark cycle the acrophases were shifted in ADX rats with respect to control rats. Under constant light conditions ADX rats displayed free-running rhythms, similar to those of control rats. The periods were stable in blind rats but not in rats maintained on a constant light cycle. The abrupt change in period, which occurred after approximately 8 days, suggests a stage of internal desynchronization. A 6-h delay in the administration of cor

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Lax, Pedro, Salvador Zamora, and Juan A. Madrid. "Coupling effect of locomotor activity on the rat’s circadian system." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, no. 2 (August 1, 1998): R580—R587. http://dx.doi.org/10.1152/ajpregu.1998.275.2.r580.

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Exercise is recognized to affect circadian rhythmicity in a variety of ways. It masks the expression of other behavioral and physiological rhythms, entrains the master pacemaker, and influences the free-running period of other rhythms. In this paper we study the influence of exercise on the organization of the timing system by analyzing the effect of voluntary locomotor activity on the circadian feeding behavior of rats subjected to different lighting conditions. The availability of wheel running prevented loss of feeding circadian rhythmicity under constant bright light (LL) but did not elici

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Van Reeth, O., and F. W. Turek. "Daily injections of triazolam induce long-term changes in hamster circadian period." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 259, no. 3 (September 1, 1990): R514—R520. http://dx.doi.org/10.1152/ajpregu.1990.259.3.r514.

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Previous experiments in hamsters indicate that daily injections of the short-acting benzodiazepine, triazolam, can entrain the free-running circadian activity rhythm to the period of the injections and that, after discontinuation of triazolam injections, the period of the free-running activity rhythm remains close to that of the previous injection schedule for 20-50 cycles. In this paper, we extend these findings and demonstrate that 1) long-term treatment with triazolam can induce aftereffects on the period of the circadian clock underlying the activity rhythm that can last for up to 100 days

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Bulthuis, Nicholas, Katrina R. Spontak, Benjamin Kleeman, and Daniel J. Cavanaugh. "Neuronal Activity in Non-LNv Clock Cells Is Required to Produce Free-Running Rest:Activity Rhythms in Drosophila." Journal of Biological Rhythms 34, no. 3 (April 17, 2019): 249–71. http://dx.doi.org/10.1177/0748730419841468.

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Circadian rhythms in behavior and physiology are produced by central brain clock neurons that can be divided into subpopulations based on molecular and functional characteristics. It has become clear that coherent behavioral rhythms result from the coordinated action of these clock neuron populations, but many questions remain regarding the organizational logic of the clock network. Here we used targeted genetic tools in Drosophila to eliminate either molecular clock function or neuronal activity in discrete clock neuron subsets. We find that neuronal firing is necessary across multiple clock

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Seggio, Joseph A., Bernard Possidente, and S. Tariq Ahmad. "Larval Ethanol Exposure Alters Adult Circadian Free-Running Locomotor Activity Rhythm inDrosophila melanogaster." Chronobiology International 29, no. 1 (January 4, 2012): 75–81. http://dx.doi.org/10.3109/07420528.2011.635236.

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Greene, Andrew V., Nancy Keller, Hubertus Haas, and Deborah Bell-Pedersen. "A Circadian Oscillator in Aspergillus spp. Regulates Daily Development and Gene Expression." Eukaryotic Cell 2, no. 2 (April 2003): 231–37. http://dx.doi.org/10.1128/ec.2.2.231-237.2003.

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ABSTRACT We have established the presence of a circadian clock in Aspergillus flavus and Aspergillus nidulans by morphological and molecular assays, respectively. In A. flavus, the clock regulates an easily assayable rhythm in the development of sclerotia, which are large survival structures produced by many fungi. This developmental rhythm exhibits all of the principal clock properties. The rhythm is maintained in constant environmental conditions with a period of 33 h at 30°C, it can be entrained by environmental signals, and it is temperature compensated. This endogenous 33-h period is one

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Masana, Monica I., Isabel C. Sumaya, Michael Becker-Andre та Margarita L. Dubocovich. "Behavioral characterization and modulation of circadian rhythms by light and melatonin in C3H/HeN mice homozygous for the RORβ knockout". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 292, № 6 (червень 2007): R2357—R2367. http://dx.doi.org/10.1152/ajpregu.00687.2006.

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This study reports for the first time the effects of retinoid-related orphan receptors [RORβ; receptor gene deletion RORβ(C3H)−/−] in C3H/HeN mice on behavioral and circadian phenotypes. Pineal melatonin levels showed a robust diurnal rhythm with high levels at night in wild-type (+/+), heterozygous (+/−), and knockout (−/−) mice. The RORβ(C3H)−/− mice displayed motor (“duck gait,” hind paw clasping reflex) and olfactory deficits, and reduced anxiety and learned helplessness-related behaviors. Circadian rhythms of wheel-running activity in all genotypes showed entrainment to the light-dark (LD

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Laakso, M. L., T. Porkka-Heiskanen, L. Leinonen, S. L. Joutsiniemi, and P. T. Mannisto. "Hormonal and locomotor activity rhythms in rats under 90-min dark-pulse conditions." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 264, no. 6 (June 1, 1993): R1058—R1064. http://dx.doi.org/10.1152/ajpregu.1993.264.6.r1058.

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The ability of a short dark pulse to entrain the circadian rhythms in rats was investigated. Pineal melatonin contents and serum levels of corticosterone and thyrotropin, a thyroid-stimulating hormone (TSH), were measured and locomotor activity was recorded under 12:12-h light-dark cycles (LD; darkness from 1800 to 0600 h) and under a 22.5:1.5 h LD lighting schedule (darkness from 1800 to 1930 h). The 90-min dark pulse was enough to trigger the rise of melatonin synthesis, but a free-running component was detected in the locomotor activity. Corticosterone levels showed diurnal variations under

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HONMA, Ken-ichi, Sato HONMA, and Tsutomu HIROSHIGE. "Response curve, free-running period, and activity time in circadian locomotor rhythm of rats." Japanese Journal of Physiology 35, no. 4 (1985): 643–58. http://dx.doi.org/10.2170/jjphysiol.35.643.

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Takahashi, Kiyohisa, Mizuo Takashima, Ken Ohi, Naoto Yamada, and Kazutaka Shimoda. "Environmental factors influencing the free-running period of locomotor activity rhythm in blinded rats." Neuroscience Research Supplements 5 (January 1987): S134. http://dx.doi.org/10.1016/0921-8696(87)90281-7.

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Kitamura, Shingo, Akiko Hida, Minori Enomoto, Makiko Watanabe, Yasuko Katayose, Kentaro Nozaki, Sayaka Aritake, et al. "Intrinsic Circadian Period of Sighted Patients with Circadian Rhythm Sleep Disorder, Free-Running Type." Biological Psychiatry 73, no. 1 (January 2013): 63–69. http://dx.doi.org/10.1016/j.biopsych.2012.06.027.

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McMeechan, Fiona K., Andrea Manica, and William A. Foster. "Rhythms of activity and foraging in the intertidal insect Anurida maritima: coping with the tide." Journal of the Marine Biological Association of the United Kingdom 80, no. 1 (February 2000): 189–90. http://dx.doi.org/10.1017/s0025315499001770.

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The intertidal insect Anurida maritima (Apterygota: Collembola) has a circatidal rhythm of locomotory activity on the soil surface which was observed during both the day and the night. The main function of this activity was foraging for food. When a superabundant food supply was provided on the upper shore, this completely repressed the usual migration to the lower shore. There was a clear rhythm in feeding activity which was highest shortly after the sea uncovered the insects' shelters and declined rapidly during the intertidal period. The circatidal rhythm of locomotory activity persisted in

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Steiger, Silke S., Mihai Valcu, Kamiel Spoelstra, Barbara Helm, Martin Wikelski, and Bart Kempenaers. "When the sun never sets: diverse activity rhythms under continuous daylight in free-living arctic-breeding birds." Proceedings of the Royal Society B: Biological Sciences 280, no. 1764 (August 7, 2013): 20131016. http://dx.doi.org/10.1098/rspb.2013.1016.

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Circadian clocks are centrally involved in the regulation of daily behavioural and physiological processes. These clocks are synchronized to the 24 h day by external cues ( Zeitgeber ), the most important of which is the light–dark cycle. In polar environments, however, the strength of the Zeitgeber is greatly reduced around the summer and winter solstices (continuous daylight or continuous darkness). How animals time their behaviour under such conditions has rarely been studied in the wild. Using a radio-telemetry-based system, we investigated daily activity rhythms under continuous daylight

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Ono, Daisuke, Sato Honma, Yoshihiro Nakajima, Shigeru Kuroda, Ryosuke Enoki, and Ken-ichi Honma. "Dissociation of Per1 and Bmal1 circadian rhythms in the suprachiasmatic nucleus in parallel with behavioral outputs." Proceedings of the National Academy of Sciences 114, no. 18 (April 17, 2017): E3699—E3708. http://dx.doi.org/10.1073/pnas.1613374114.

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The temporal order of physiology and behavior in mammals is primarily regulated by the circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Taking advantage of bioluminescence reporters, we monitored the circadian rhythms of the expression of clock genes Per1 and Bmal1 in the SCN of freely moving mice and found that the rate of phase shifts induced by a single light pulse was different in the two rhythms. The Per1-luc rhythm was phase-delayed instantaneously by the light presented at the subjective evening in parallel with the activity onset of behavioral rhythm, wher

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Colwell, Christopher S., Stephan Michel, Jason Itri, Williams Rodriguez, J. Tam, Vincent Lelievre, Zhou Hu, X. Liu, and James A. Waschek. "Disrupted circadian rhythms in VIP- and PHI-deficient mice." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 285, no. 5 (November 2003): R939—R949. http://dx.doi.org/10.1152/ajpregu.00200.2003.

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The related neuropeptides vasoactive intestinal peptide (VIP) and peptide histidine isoleucine (PHI) are expressed at high levels in the neurons of the suprachiasmatic nucleus (SCN), but their function in the regulation of circadian rhythms is unknown. To study the role of these peptides on the circadian system in vivo, a new mouse model was developed in which both VIP and PHI genes were disrupted by homologous recombination. In a light-dark cycle, these mice exhibited diurnal rhythms in activity which were largely indistinguishable from wild-type controls. In constant darkness, the VIP/PHI-de

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Ruby, N. F., A. Saran, T. Kang, P. Franken, and H. C. Heller. "Siberian hamsters free run or become arrhythmic after a phase delay of the photocycle." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 271, no. 4 (October 1, 1996): R881—R890. http://dx.doi.org/10.1152/ajpregu.1996.271.4.r881.

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Body temperature (Tb) and locomotor activity were recorded telemetrically from male Siberian hamsters (Phodopus sungorus sungorus) that were 3 or 12 mo of age and maintained in a light-dark (LD) cycle of 16 h light/day for 2-4 mo. After 3 wk of Tb recording, the LD cycle was phase delayed by extending the light phase by 5 h for 1 day; animals remained on a 16:8-h LD cycle for the remainder of the experiment. Tb and activity rhythms of all animals were stably entrained to the LD cycle before the phase shift. After the phase shift, > or = 80% of the animals in each age group failed to reentra

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Gilberstadt, M. L., L. L. Bellinger, S. Lindblad, and W. C. Duane. "Liver denervation does not alter the circadian rhythm of bile acid synthesis in rats." American Journal of Physiology-Gastrointestinal and Liver Physiology 261, no. 5 (November 1, 1991): G799—G802. http://dx.doi.org/10.1152/ajpgi.1991.261.5.g799.

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In both rats and humans there is a distinct circadian rhythm of bile acid synthesis that is independent of feedback regulation. To determine whether the circadian rhythm is directly mediated via hepatic nerves, bile acid synthesis was studied in selectively liver-denervated male Sprague-Dawley rats in a bile fistula model. Complete denervation was confirmed by histofluorescent staining for neural elements in frozen sections of livers. There was no significant difference in mean bile acid synthesis, amplitude of the circadian rhythm, or time of peak synthesis between the denervated rats and non

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Eskandari, Rosa, Lalanthi Ratnayake, and Patricia L. Lakin-Thomas. "Shared Components of the FRQ-Less Oscillator and TOR Pathway Maintain Rhythmicity in Neurospora." Journal of Biological Rhythms 36, no. 4 (April 7, 2021): 329–45. http://dx.doi.org/10.1177/0748730421999948.

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Molecular models for the endogenous oscillators that drive circadian rhythms in eukaryotes center on rhythmic transcription/translation of a small number of “clock genes.” Although substantial evidence supports the concept that negative and positive transcription/translation feedback loops (TTFLs) are responsible for regulating the expression of these clock genes, certain rhythms in the filamentous fungus Neurospora crassa continue even when clock genes ( frq, wc-1, and wc-2) are not rhythmically expressed. Identification of the rhythmic processes operating outside of the TTFL has been a major

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Strogatz, S. H., R. E. Kronauer, and C. A. Czeisler. "Circadian pacemaker interferes with sleep onset at specific times each day: role in insomnia." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 253, no. 1 (July 1, 1987): R172—R178. http://dx.doi.org/10.1152/ajpregu.1987.253.1.r172.

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The human circadian pacemaker modulates our desire and ability to fall asleep at different times of day. To study this circadian component of sleep tendency, we have analyzed the sleep-wake patterns recorded from 15 free-running subjects in whom the sleep-wake cycle spontaneously desynchronized from the circadian rhythm of body temperature. The analysis indicates that the distribution of sleep onsets during free run is bimodal, with one peak at the temperature trough and, contrary to previous reports, a second peak 9-10 h later. Furthermore, there are two consistent zones in the circadian temp

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Maywood, E. S., M. H. Hastings, M. Max, E. Ampleford, M. Menaker, and A. S. I. Loudon. "Circadian and daily rhythms of melatonin in the blood and pineal gland of free-running and entrained Syrian hamsters." Journal of Endocrinology 136, no. 1 (January 1993): 65–73. http://dx.doi.org/10.1677/joe.0.1360065.

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ABSTRACT The aim of this study was to develop a radioimmunoassay for the measurement of endogenous circulating melatonin concentrations in the Syrian hamster, and then to determine the effect of various photic manipulations upon this endocrine signal. In experiment 1, pineal-intact or pinealectomized adult male Syrian hamsters, housed under a long photoperiod (LD; 16 h light:8 h darkness) for 2 weeks, were then either maintained on LD or transferred to a short photoperiod (SD; 8 h light:16 h darkness) for a further 8 weeks. The profile of serum melatonin concentrations was determined from bloo

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