Seasonal changes in the circadian period of the lake chub, Couesius plumbeus

1978 ◽  
Vol 56 (12) ◽  
pp. 2591-2596 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Seasonal Changes ◽  
Constant Darkness ◽  
Circadian Period ◽  
Minimum Period ◽  
Annual Variations ◽  
Circadian Organization ◽  
Annual Changes ◽  
The Times ◽  
Couesius Plumbeus

Systematic seasonal and annual changes are present in the length of the circadian period, τ, of the lake chub, Couesius plumbeus. Maximum and minimum period values of 28.1 and 24.8 h were recorded under constant darkness from fish obtained at the times of the winter and summer solstices, respectively. There was an asymmetric annual pattern in the τ values obtained from the increasing and decreasing photoperiods of spring and fall. Annual variations in τ were relatively independent of temperature. They were interpreted as being aftereffects of natural photoperiodic entrainment. Relations of annual changes in the length of the period to models of circadian organization and entrainment are examined.

Seasonal changes in the short-term activity and ultradian rhythms of a cyprinid fish, the lake chub, Couesius plumbeus

1981 ◽  
Vol 59 (3) ◽  
pp. 486-492 ◽  
Author(s):  
Martin Kavaliers
Keyword(s):  
Seasonal Changes ◽  
Temporal Pattern ◽  
Circadian System ◽  
Cyprinid Fish ◽  
Constant Darkness ◽  
Ultradian Rhythms ◽  
Short Term ◽  
Free Running ◽  
Annual Changes ◽  
Couesius Plumbeus

The temporal pattern of the locomotor activity of a cyprinid fish, the lake chub, Couesius plumbeus, was examined under seasonally appropriate light–dark cycles that included twilights and under constant darkness. Photoperiodically entrained and free-running circadian activity from constant darkness was composed of nonrandomly distributed short-term activity components (0.5–3.5 h) with significant ultradian frequencies. In both cases there was an annual rhythm in the length of the ultradian periods, ranging from 0.7 h in winter to 2.5 h in summer. This pattern was accompanied by annual changes in the frequency distribution of short-term activity components. Ultradian periods were correlated with both daylength in the entraining light–dark cycles and the seasonal changes in the circadian period of fish free-running under constant darkness. These results suggest that the expression of ultradian rhythms and short-term locomotor bouts is controlled by a multioscillator circadian system.

Twilight and day length affects the seasonality of entrainment and endogenous circadian rhythms in a fish, Couesius plumbeus

1981 ◽  
Vol 59 (7) ◽  
pp. 1326-1334 ◽  
Author(s):  
Martin Kavaliers ◽  
Donald M. Ross
Keyword(s):  
Circadian Rhythms ◽  
Seasonal Changes ◽  
Phase Relationship ◽  
Day Length ◽  
Constant Darkness ◽  
Diurnal Activity ◽  
Circadian Period ◽  
Dark Cycle ◽  
Environmental Light ◽  
Couesius Plumbeus

Twilight and day-length portions of the light-dark cycle determine the seasonal course of (i) the phase relationship (ψ) between activity and the daily environmental light–dark cycle, (ii) the duration of activity (α), and (iii) the circadian period (τ) under constant darkness of the lake chub (Couesius plumbeus). With fish held under seasonally appropriate light–dark cycles with twilight (LD + t), the onset of diurnal activity occurred during dawn and its timing (ψonset) followed a bimodal annual pattern that was correlated with seasonal changes in the duration and physical characteristics of twilight. The end of activity occurred during dusk (ψoffset) and followed a unimodal annual pattern that was determined by day length. α followed a sigmoidal annual pattern under LD + t. The circadian period underwent significant seasonal changes with maximum and minimum τ values occurring during summer and winter, respectively. Fish that were entrained to rectangular light–dark cycles that excluded twilights (LD) failed to show any seasonal changes in ψ and τ and the sigmoidal relation between α and day length was absent.

scholarly journals Intra-Annual Variability of the Radiocarbon Content of Corals from the Galapagos Islands

Radiocarbon ◽  
1993 ◽  
Vol 35 (2) ◽  
pp. 245-251 ◽  
Author(s):  
T. A. Brown ◽  
G. W. Farwell ◽  
P. M. Grootes ◽  
F. H. Schmidt ◽  
Minze Stuiver
Keyword(s):  
Southern Oscillation ◽  
Galapagos Islands ◽  
Ocean Current ◽  
Galápagos Islands ◽  
Ocean Water ◽  
Annual Variations ◽  
Surface Ocean ◽  
Annual Variability ◽  
Annual Changes ◽  
Detailed Record

We report AMS 14C measurements on subannual samples of coral from the Galapagos Islands that span the period, 1970–1973. Both the major 1972 El Niño/Southern Oscillation event and intra-annual changes in regional upwelling of 14C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. Our data show that the corals preserve a detailed record of past intra-annual variations of the 14C content of surface ocean water.

Annual Variations in Rheotactic Behaviour and Seawater Adaptability in Landlocked Arctic Char (Salvelinus alpinus)

1992 ◽  
Vol 49 (3) ◽  
pp. 448-452 ◽  
Author(s):  
Monika Schmitz
Keyword(s):  
Seasonal Changes ◽  
Salvelinus Alpinus ◽  
Challenge Test ◽  
Early Summer ◽  
Rapid Decrease ◽  
Arctic Char ◽  
Migratory Behaviour ◽  
Annual Variations ◽  
Seawater Tolerance ◽  
Seawater Challenge

The existence of basic smoltification characteristics, measured by means of seasonal changes in rheotactic behaviour and seawater adaptability, was studied from February to November in 1- and 2-yr-old landlocked Arctic char (Salvelinus alpinus). Up- and downstream directed movements were monitored in an annular stream tank at a water velocity of 0.2 m/s. A 48-h seawater challenge test using 25‰ seawater was performed at monthly intervals throughout the year to assess seawater adaptability. The 1-yr-old char displayed mainly nondirectional behaviour during spring, but from August onwards the movements were predominantly against the current. Seawater performance improved slightly in this group in May and June. The 2-yr-old char progressively developed a downstream behaviour and exhibited an increased seawater adaptability during spring and early summer. In late August, a marked reversal in rheotactic behaviour occurred, followed by a rapid decrease in seawater tolerance. The results demonstrate that seasonal changes in seawater adaptability and changes in migratory behaviour which were directionally consistent with smolting still exist in a population of Arctic char that has been landlocked for about 6000 yr.

Circadian organization of chitin in some insect skeletons

1965 ◽  
Vol s3-106 (76) ◽  
pp. 315-325
Author(s):  
A. C. NEVILLE
Keyword(s):  
Circadian Clock ◽  
General Feature ◽  
Periplaneta Americana ◽  
Constant Darkness ◽  
Actual Rate ◽  
Rate Of Increase ◽  
Parallel Fibres ◽  
Astronomical Clock ◽  
Circadian Organization ◽  
Water Bugs

A circadian clock is shown to be involved in the control of macromolecular orientation of chitin by cells secreting and organizing insect endocuticle. Daily organization of locust endocuticle into alternating lamellate and non-lamellate layers persists in constant temperature (36° C) and constant darkness for at least 2 weeks; the freerunning period is then about 23 h, so that after a number of days the circadian clock is 180° out of phase with the astronomical clock, with which it is normally phased. The rhythm is almost independent of temperature, with a Q10 of 1.04, as contrasted with a Q10 of 2.0 for the actual rate of increase of endocuticular thickness. Locust epidermal cells differ in response to specific imposed environmental conditions according to their location in the integument. In some cells, constant low temperature uncouples chitin lamellogenesis from the circadian clock, provided that illumination (light or dark) is constant also: the result is continuously lamellate endocuticle. In other cells constant light acts as an uncoupling factor, provided that temperature (high or low) is constant also: the result in this case is continuously non-lamellate endocuticle. The circadian rhythm of chitin lamellogenesis persists in a cave cricket (Dolichopoda linderi). A similar circadian lamellogenesis rhythm occurs in the endocuticle of nymphs and adults of the cockroach Periplaneta americana. A crossed-fibre multiple-ply endocuticle in the legs and wings of giant toe-biter water bugs (Belosto-matidae) also displays circadian organization, the chitin macromolecules in any one layer lying in parallel fibres, at an angle of approximately 6o° to those in the next layer. It is suggested that daily organization of the skeleton may be a general feature of arthropods. Examples include the phenomena of timing of chitin lamellogenesis; chitin crossed-fibrillar organization; degree of fluorescence of the rubber-like protein resilin; and mineralization of crayfish gastroliths.

Genetic analysis of daily physical activity using a mouse chromosome substitution strain

2009 ◽  
Vol 39 (1) ◽  
pp. 47-55 ◽  
Author(s):  
He S. Yang ◽  
Martha H. Vitaterna ◽  
Aaron D. Laposky ◽  
Kazuhiro Shimomura ◽  
Fred W. Turek
Keyword(s):  
Physical Activity ◽  
Physical Activity Level ◽  
Wheel Running ◽  
Daily Physical Activity ◽  
Activity Level ◽  
Constant Darkness ◽  
Circadian Period ◽  
Chromosome 13 ◽  
Running Activity ◽  
Wheel Running Activity

There is considerable evidence for a genetic basis underlying individual differences in spontaneous physical activity in humans and animals. Previous publications indicate that the physical activity level and pattern vary among inbred strains of mice and identified a genomic region on chromosome 13 as quantitative trait loci (QTL) for physical activity. To confirm and further characterize the role of chromosome 13 in regulating daily physical activity level and pattern, we conducted a comprehensive phenotypic study in the chromosome 13 substitution strain (CSS-13) in which the individual chromosome 13 from the A/J strain was substituted into an otherwise complete C57BL/6J (B6) genome. The B6 and A/J parental strains exhibited pronounced differences in daily physical activity, sleep-wake structure, circadian period and body weight. Here we report that a single A/J chromosome 13 in the context of a B6 genetic background conferred a profound reduction in both total cage activity and wheel-running activity under a 14:10-h light-dark cycle, as well as in constant darkness, compared with B6 controls. Additionally, CSS-13 mice differed from B6 controls in the diurnal distribution of activity and the day-to-day variability in activity onset. We further performed a linkage analysis and mapped a significant QTL on chromosome 13 regulating the daily wheel running activity level in mice. Taken together, our findings indicate a QTL on chromosome 13 with dramatic and specific effects on daily voluntary physical activity, but not on circadian period, sleep, or other aspects of activity that are different between B6 and A/J strains.

Functioning of the rat circadian system is modified by light applied in critical postnatal days

2001 ◽  
Vol 280 (4) ◽  
pp. R1023-R1030 ◽  
Author(s):  
M. M. Canal-Corretger ◽  
J. Vilaplana ◽  
T. Cambras ◽  
A. Díez-Noguera
Keyword(s):  
Light Pulse ◽  
Critical Period ◽  
Decisive Role ◽  
Circadian System ◽  
Constant Darkness ◽  
Biological Clocks ◽  
Critical Window ◽  
Lighting Conditions ◽  
Lactation Stage ◽  
Circadian Organization

Lighting conditions influence biological clocks. The present experiment was designed to test the presence of a critical window of days during the lactation stage of the rat in which light has a decisive role on the development of the circadian system. Rats were exposed to 4, 8, or 12 days of constant light (LL) during the first days of life. Their circadian rhythm was later studied under LL and constant darkness. The response to a light pulse was also examined. Results show that the greater the number of LL days during lactation, the stronger the rhythm under LL and the smaller the phase shift due to the light pulse. These responses are enhanced when rats are exposed to LL days around postnatal day 12. A mathematical model was built to explain the responses of the circadian system with respect to the timing of LL during lactation, and we deduced that between postnatal days 10 to 20there is a critical period of sensitivity to light; consequently, exposure to LL during this time modifies the circadian organization of the motor activity.

scholarly journals Identification of Genes Contributing to a Long Circadian Period in Drosophila Melanogaster

2020 ◽  
pp. 074873042097594
Author(s):  
Shailesh Kumar ◽  
Ilker Tunc ◽  
Terry R. Tansey ◽  
Mehdi Pirooznia ◽  
Susan T. Harbison
Keyword(s):  
Locomotor Activity ◽  
Genome Wide Association Study ◽  
Clock Genes ◽  
Critical Role ◽  
Constant Darkness ◽  
Circadian Period ◽  
Wild Type ◽  
Genetic Rescue ◽  
Long Period ◽  
Activity Behavior

The endogenous circadian period of animals and humans is typically very close to 24 h. Individuals with much longer circadian periods have been observed, however, and in the case of humans, these deviations have health implications. Previously, we observed a line of Drosophila with a very long average period of 31.3 h for locomotor activity behavior. Preliminary mapping indicated that the long period did not map to known canonical clock genes but instead mapped to multiple chromosomes. Using RNA-Seq, we surveyed the whole transcriptome of fly heads from this line across time and compared it with a wild-type control. A three-way generalized linear model revealed that approximately two-thirds of the genes were expressed differentially among the two genotypes, while only one quarter of the genes varied across time. Using these results, we applied algorithms to search for genes that oscillated over 24 h, identifying genes not previously known to cycle. We identified 166 differentially expressed genes that overlapped with a previous Genome-wide Association Study (GWAS) of circadian behavior, strongly implicating them in the long-period phenotype. We tested mutations in 45 of these genes for their effect on the circadian period. Mutations in Alk, alph, CG10089, CG42540, CG6034, Kairos ( CG6123), CG8768, klg, Lar, sick, and tinc had significant effects on the circadian period, with seven of these mutations increasing the circadian period of locomotor activity behavior. Genetic rescue of mutant Kairos restored the circadian period to wild-type levels, suggesting it has a critical role in determining period length in constant darkness.

Homeostatic regulation of sleep in arrhythmic Siberian hamsters

2004 ◽  
Vol 287 (1) ◽  
pp. R104-R111 ◽  
Author(s):  
Jennie E. Larkin ◽  
Tohei Yokogawa ◽  
H. Craig Heller ◽  
Paul Franken ◽  
Norman F. Ruby
Keyword(s):  
Constant Darkness ◽  
Sleep Regulation ◽  
Light Phase ◽  
Compensatory Response ◽  
Recovery Sleep ◽  
Siberian Hamsters ◽  
Novel Approach ◽  
Sleep Homeostasis ◽  
Circadian Organization ◽  
Simple Phase

Sleep is regulated by independent yet interacting circadian and homeostatic processes. The present study used a novel approach to study sleep homeostasis in the absence of circadian influences by exposing Siberian hamsters to a simple phase delay of the photocycle to make them arrhythmic. Because these hamsters lacked any circadian organization, their sleep homeostasis could be studied in the absence of circadian interactions. Control animals retained circadian rhythmicity after the phase shift and re-entrained to the phase-shifted photocycle. These animals displayed robust daily sleep-wake rhythms with consolidated sleep during the light phase beginning about 1 h after light onset. This marked sleep-wake pattern was circadian in that it persisted in constant darkness. The distribution of sleep in the arrhythmic hamsters over 24 h was similar to that in the light phase of rhythmic animals. Therefore, daily sleep amounts were higher in arrhythmic animals compared with rhythmic ones. During 2- and 6-h sleep deprivations (SD), it was more difficult to keep arrhythmic hamsters awake than it was for rhythmic hamsters. Because the arrhythmic animals obtained more non-rapid eye movement sleep (NREMS) during the SD, they showed a diminished compensatory response in NREMS EEG slow-wave activity during recovery sleep. When amounts of sleep during the SD were taken into account, there were no differences in sleep homeostasis between experimental and control hamsters. Thus loss of circadian control did not alter the homeostatic response to SD. This supports the view that circadian and homeostatic influences on sleep regulation are independent processes.

scholarly journals Neuron-specific knockouts indicate the importance of network communication to Drosophila rhythmicity

2019 ◽  
Author(s):  
M Schlichting ◽  
MM Diaz ◽  
J Xin ◽  
M Rosbash
Keyword(s):  
Gene Expression ◽  
Circadian Rhythms ◽  
Intercellular Communication ◽  
Clock Gene ◽  
Feedback Loops ◽  
Neuronal Firing ◽  
Network Communication ◽  
Constant Darkness ◽  
Circadian Period ◽  
Clock Gene Expression

AbstractAnimal circadian rhythms persist in constant darkness and are driven by intracellular transcription-translation feedback loops. Although these cellular oscillators communicate, isolated mammalian cellular clocks continue to tick away in darkness without intercellular communication. To investigate these issues in Drosophila, we assayed behavior as well as molecular rhythms within individual brain clock neurons while blocking communication within the ca. 150 neuron clock network. We also generated CRISPR-mediated neuron-specific circadian clock knockouts. The results point to two key clock neuron groups: loss of the clock within both regions but neither one alone has a strong behavioral phenotype in darkness; communication between these regions also contributes to circadian period determination. Under these dark conditions, the clock within one region persists without network communication. The clock within the famous PDF-expressing s-LNv neurons however was strongly dependent on network communication, likely because clock gene expression within these vulnerable sLNvs depends on neuronal firing or light.

Sign in / Sign up

Export Citation Format

Share Document