The Effect of Photoperiod on the Developmental Rate of Drosophila Pupae

1965 ◽  
Vol 43 (3) ◽  
pp. 411-423
Author(s):  
JANET E. HARKER
Keyword(s):  
Dark Period ◽  
Developmental Rate ◽  
Time Of Day ◽  
Constant Darkness ◽  
Time Interval ◽  
Simple Relationship ◽  
Light Cycle ◽  
Rate Of Development ◽  
Eclosion Rhythm ◽  
Developmental Rates

1. The time taken for Drosophila melanogaster to complete three stages of pupal development has been measured for pupae entering each stage at each particular hour of the day in cycles of 12 hr. light:12 hr. darkness, 4 hr. light:20 hr. darkness, 18 hr. light:6 hr. darkness. Similar measurements have been made for insects in which the larvae were subjected to the light cycles but the pupae remained in constant darkness. 2. The duration of each stage is affected by the time of day, relative to the light cycle, at which the stage is entered. When pupae are in constant darkness the developmental rate of each stage is affected by the time of day at which the stage is entered relative to the particular light cycle to which the larval stage had been exposed. 3. The eclosion rhythm, which arises as a summation effect of rhythms of development at earlier stages, may become bimodal in light cycles with suitable photofractions. 4. The rate of development of a pupa entering a stage during the light period is related to the time-interval since the light-on signal; the preceding dark period has no effect. 5. The developmental rate of pupa entering a stage during the dark period is affected by the time-interval since the light-off signal, but may also be affected by the previous light-on signal although there is no simple relationship between them. 6. As the developmental rates are maintained in constant darkness it is concluded that the rate of development is affected by factors following a diurnal rhythm. The form of the rhythm is determined by both light-on and light off signals, but the timing of the rhythm is determined by the two signals acting independently of each other.

The Effect of a Biological Clock on the Developmental Rate of Drosophila Pupae

1965 ◽  
Vol 42 (2) ◽  
pp. 323-337
Author(s):  
JANET E. HARKER
Keyword(s):  
Biological Clock ◽  
Bright Light ◽  
Developmental Rate ◽  
Time Of Day ◽  
Time Interval ◽  
Light Cycle ◽  
Continuous Darkness ◽  
Pupal Development ◽  
Wide Range ◽  
Three Stages

1. A study of the course of pupal development in two strains of Drosophila melanogaster has been made in an attempt to establish the factors affecting the time of adult eclosion. 2. The time taken to complete three stages of pupal development has been measured for pupae entering each stage at each particular hour of the day when insects were kept in 12 hr. light:12 hr. darkness, 12 hr. bright light: 12 hr. dim light, or in continuous darkness. 3. The duration of each stage, in both strains, is affected by the time of day, relative to the light cycle, at which the stage is entered. The duration of each stage for pupae kept in continuous darkness is affected by the time of day at which the stage is entered, relative to the light cycle to which they had been exposed as larvae. 4. The time-interval curves for all three stages of any one strain take the same form. 5. Because of the very wide range of developmental rates, dependent upon the time within the light cycle at which each stage begins, a population in which the larvae all pupate within a 24 hr. period will continue to produce adult flies over several days. 6. The eclosion rhythm is a population effect and does not reflect the phasing of individuals to a dawn eclosion; the majority of adults emerge at dawn because of the summation effect of circadian rhythms of development at earlier stages.

Disrupted circadian rhythms in VIP- and PHI-deficient mice

2003 ◽  
Vol 285 (5) ◽  
pp. R939-R949 ◽  
Author(s):  
Christopher S. Colwell ◽  
Stephan Michel ◽  
Jason Itri ◽  
Williams Rodriguez ◽  
J. Tam ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Wheel Running ◽  
Activity Rhythm ◽  
Activity Patterns ◽  
Circadian System ◽  
Diurnal Rhythms ◽  
Constant Darkness ◽  
Light Cycle ◽  
Wild Type ◽  
Deficient Mice

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-deficient mice exhibited pronounced abnormalities in their circadian system. The activity patterns started ∼8 h earlier than predicted by the previous light cycle. In addition, lack of VIP/PHI led to a shortened free-running period and a loss of the coherence and precision of the circadian locomotor activity rhythm. In about one-quarter of VIP/PHI mice examined, the wheel-running rhythm became arrhythmic after several weeks in constant darkness. Another striking example of these deficits is seen in the split-activity patterns expressed by the mutant mice when they were exposed to a skeleton photoperiod. In addition, the VIP/PHI-deficient mice exhibited deficits in the response of their circadian system to light. Electrophysiological analysis indicates that VIP enhances inhibitory synaptic transmission within the SCN of wild-type and VIP/PHI-deficient mice. Together, the observations suggest that VIP/PHI peptides are critically involved in both the generation of circadian oscillations as well as the normal synchronization of these rhythms to light.

A circadian rhythm in the locomotive behaviour of the giant garden slug Limax maximus

1977 ◽  
Vol 66 (1) ◽  
pp. 47-64
Author(s):  
P. G. Sokolove ◽  
C. M. Beiswanger ◽  
D. J. Prior ◽  
A. Gelperin
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Phase Angle ◽  
Circadian Rhythmicity ◽  
Constant Darkness ◽  
Light Cycle ◽  
Circadian Activity ◽  
Locomotor Rhythm ◽  
Activity Peak ◽  
Limax Maximus

The locomotor activity of the garden slug Limax maximus was examined for components of circadian rhythmicity. Behavioural (running wheel) studies clearly demonstrated that the activity satisfies the principal criteria of circadian rhythmicity. In constant darkness at a constant temperature, the locomotor activity freeran with a period of about 24 h (range 23-6-24-6 h). The rhythm was also expressed in constant light with a period for individual slugs that tended to be shorter in LL than in DD. The period of the rhythm was temperature compensated (11–5-21-5 degrees C) with a Q10 approximately equal to 1–00. The locomotor rhythm could be entrained to 24 h LD cycles such that the circadian activity peak occurred during the dark. The phase angle between the onset of activity and lights-off was not fixed, but was a function of the photoperiod of the entraining light cycle.

Organization of rat circadian rhythms during daily infusion of melatonin or S20098, a melatonin agonist

1999 ◽  
Vol 277 (3) ◽  
pp. R812-R828 ◽  
Author(s):  
B. Pitrosky ◽  
R. Kirsch ◽  
A. Malan ◽  
E. Mocaer ◽  
P. Pevet
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Phase Response Curve ◽  
Constant Darkness ◽  
Time Interval ◽  
General Activity ◽  
Activity Peak ◽  
Free Running ◽  
Wheel Activity ◽  
Free Running Period

Daily administration of melatonin or S20098, a melatonin agonist, is known to entrain the free-running circadian rhythms of rats. The effects of the duration of administration on entrainment were studied. The animals demonstrated free-running circadian rhythms (running-wheel activity, body temperature, general activity) in constant darkness. Daily infusions of melatonin or S20098 for 1, 8, or 16 h entrained the circadian rhythms to 24 h. Two daily infusions of 1 h (separated by 8 h) entrained the activity peak within the shorter time interval. The entraining properties of melatonin and S20098 were similar and were affected neither by pinealectomy nor by infusion of 1- or 8-h duration. However, with 16-h infusion, less than half of the animals became entrained. Once entrained, the phase angle between the onset of infusion and the rhythms (onset of activity or acrophase of body temperature) increased with the duration of infusion. Before entrainment, the free-running period increased with the duration of infusion, an effect that was not predictable from the phase response curve.

scholarly journals Day and night in the subterranean: measuring daily activity patterns of subterranean rodents (Ctenomys aff. knighti) using bio-logging

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Milene G Jannetti ◽  
C Loren Buck ◽  
Veronica S Valentinuzzi ◽  
Gisele A Oda
Keyword(s):  
Daily Activity ◽  
Activity Patterns ◽  
Extreme Environments ◽  
Total Duration ◽  
Time Of Day ◽  
Constant Darkness ◽  
Subterranean Rodents ◽  
Monte Desert ◽  
Direct Observations ◽  
Desert Rodents

Abstract While most studies of the impacts of climate change have investigated shifts in the spatial distribution of organisms, temporal shifts in the time of activity is another important adjustment made by animals in a changing world. Due to the importance of light and temperature cycles in shaping activity patterns, studies of activity patterns of organisms that inhabit extreme environments with respect to the 24-hour cyclicity of Earth have the potential to provide important insights into the interrelationships among abiotic variables, behaviour and physiology. Our previous laboratory studies with Argentinean tuco-tucos from the Monte desert (Ctenomys aff. knighti) show that these subterranean rodents display circadian activity/rest rhythms that can be synchronized by artificial light/dark cycles. Direct observations indicate that tuco-tucos emerge mainly for foraging and for removal of soil from their burrows. Here we used bio-logging devices for individual, long-term recording of daily activity/rest (accelerometry) and time on surface (light-loggers) of six tuco-tucos maintained in outdoor semi-natural enclosures. Environmental variables were measured simultaneously. Activity bouts were detected both during day and night but 77% of the highest values happened during the daytime and 47% of them coincided with time on surface. Statistical analyses indicate time of day and temperature as the main environmental factors modulating time on surface. In this context, the total duration that these subterranean animals spent on surface was high during the winter, averaging 3 h per day and time on surface occurred when underground temperature was lowest. Finally, transport of these animals to the indoor laboratory and subsequent assessment of their activity rhythms under constant darkness revealed a switch in the timing of activity. Plasticity of activity timing is not uncommon among desert rodents and may be adaptive in changing environments, such as the desert where this species lives.

scholarly journals Free-running circadian breathing rhythms are eliminated by suprachiasmatic nucleus lesion

2020 ◽  
Vol 129 (1) ◽  
pp. 49-57
Author(s):  
Benton S. Purnell ◽  
Gordon F. Buchanan
Keyword(s):  
Sleep Apnea ◽  
Circadian Rhythms ◽  
Suprachiasmatic Nucleus ◽  
Time Of Day ◽  
Sudden Unexpected Death ◽  
Constant Darkness ◽  
Unexpected Death ◽  
Treatment And Prevention ◽  
Free Running

It has long been appreciated that breathing is altered by time of day. This study demonstrates that rhythmicity in breathing persists in constant darkness but is dependent on the suprachiasmatic nucleus in the hypothalamus. Understanding circadian rhythms in breathing may be important for the treatment and prevention of diseases such as sleep apnea and sudden unexpected death in epilepsy.

Diurnal Variation in the Response of the Mandible to Orthopedic Force

2002 ◽  
Vol 81 (10) ◽  
pp. 711-715 ◽  
Author(s):  
S. Yamada ◽  
S. Saeki ◽  
I. Takahashi ◽  
K. Igarashi ◽  
H. Shinoda ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Dark Period ◽  
Time Of Day ◽  
Light Period ◽  
Considerable Reduction ◽  
Cartilage Metabolism ◽  
Differentiation And Proliferation ◽  
And Cartilage

Bone and cartilage metabolism is known to be more active during rest than during periods of activity. The purpose of this study was to examine the hypothesis that mandibular retractive force could be more effective when applied to rats during rest. Mandibular retractive force caused a considerable reduction in the condylar length in experimental groups, and the magnitude of this reduction was greater in the Light-period (08:00-20:00) group than in the Dark-period (20:00-08:00) group. The differentiation and proliferation of chondrocytes were inhibited in animals in the Light-period group, compared with those in the Dark-period group. These results suggest that the orthopedic effects of mandibular retractive force vary depending on the time of day the force is applied, and that such force may be more effective while animals are resting than while they are active.

Temperature thresholds and statistical modelling of larval Wuchereria bancrofti (Filariidea: Onchocercidae) developmental rates

Parasitology ◽  
1997 ◽  
Vol 114 (2) ◽  
pp. 123-134 ◽  
Author(s):  
F. LARDEUX ◽  
J. CHEFFORT
Keyword(s):  
Wuchereria Bancrofti ◽  
Developmental Rate ◽  
Statistical Modelling ◽  
Original Method ◽  
Frequency Data ◽  
Larval Stages ◽  
A Value ◽  
Temperature Thresholds ◽  
Developmental Rates ◽  
Aedes Polynesiensis

Developmental rates for Wuchereria bancrofti larvae maturing in the vector Aedes polynesiensis were estimated by analysing stage-frequency data consisting of counts of larval stages in mosquitoes reared at 20, 22·5, 25, 27·5, 30 and 32 °C. Base temperatures (i.e. low temperature thresholds) for W. bancrofti development were estimated by the x-intercept method and the model of Lactin et al. (1995). Resulting values were similar with both methods and were ≈12·5 °C for microfilariae (mf) in thorax, ≈17 °C for L1, 15·5 °C for L2 and 16·5 °C for L3. Upper thresholds estimated by the Lactin et al. model were 29·3 °C for mf, 29·1 °C for L1, 32·2 °C for L2 and 31·5 °C for L3. In addition, an original method was devised for computing the L3 upper threshold, by modelling L3 length shrinkage with temperature. It gave a value of 31·4 °C. At 32 °C, L2 and L3 stages exhibited altered morphology, larvae being shorter and wider than expected. The model of Lactin et al. described adequately the non-linear relationship between developmental rate and temperature, but a linear degree-day approach may be applied for temperatures below 27–28 °C.

Prehospital Emergency Medical Services Departure Interval: Does Patient Age Matter?

2016 ◽  
Vol 31 (6) ◽  
pp. 608-613 ◽  
Author(s):  
Bruno Schnegg ◽  
Mathieu Pasquier ◽  
Pierre-Nicolas Carron ◽  
Bertrand Yersin ◽  
Fabrice Dami
Keyword(s):  
Response Time ◽  
Emergency Medical Services ◽  
Time Of Day ◽  
Medical Services ◽  
Time Interval ◽  
Patient Age ◽  
Emergency Medical ◽  
Patient Âgé ◽  
Prehospital Emergency ◽  
The Impact

AbstractIntroductionThe concept of response time with minimal interval is intimately related to the practice of emergency medicine. The factors influencing this time interval are poorly understood.ProblemIn a process of improvement of response time, the impact of the patient’s age on ambulance departure intervals was investigated.MethodThis was a 3-year observational study. Departure intervals of ambulances, according to age of patients, were analyzed and a multivariate analysis, according to time of day and suspected medical problem, was performed.ResultsA total of 44,113 missions were included, 2,417 (5.5%) in the pediatric group. Mean departure delay for the adult group was 152.9 seconds, whereas it was 149.3 seconds for the pediatric group (P =.018).ConclusionA statistically significant departure interval difference between missions for children and adults was found. The difference, however, probably was not significant from a clinical point of view (four seconds).SchneggB, PasquierM, CarronPN, YersinB, DamiF. Prehospital Emergency Medical Services departure interval: does patient age matter?Prehosp Disaster Med. 2016;31(6):608–613.

MEIOSIS IN COPRINUS: VI. THE CONTROL OF THE INITIATION OF MEIOSIS

1974 ◽  
Vol 16 (1) ◽  
pp. 155-164 ◽  
Author(s):  
B. C. Lu
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Mycelial Growth ◽  
Dark Period ◽  
Continuous Light ◽  
Sensitive Period ◽  
Temperature Sensitive ◽  
Light Cycle ◽  
Sensitive Stage ◽  
Dark Regime

Meiosis in Coprinus lagopus is normally initiated at night under normal diurnal conditions. This timing can be shifted to 0900-1000 h by using a 16h light-8h dark regime with the light cycle commencing at 1600 h. For the initiation of meiosis, C. lagopus is temperature sensitive (35 C) under continuous light. The temperature sensitivity can be overcome by a dark period. The sensitive period occurs within 7 h of karyogmay. Only the first 2 h, however, are sensitive to light and high temperature. A shift-up to restrictive conditions before the sensitive stage effectively arrests the process leading to karyogamy. The arrest is reversible within 20 h. Upon returning to a 25 C chamber, karyogamy begins in 6 h in all basidiocarps. Thus using this technique accurate control of the initiation of meiosis can be achieved. Howeevr, prolonged arrest beyond 16 h causes the basidia to revert to mitosis and mycelial growth. The nucleolus is reduced in size and exhibits a large vacuole and a lack of granular components as shown by electron microscopy.

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