Thermal sensitivity of reptilian melatonin rhythms: "cold" tuatara vs. "warm" skink

1989 ◽  
Vol 256 (5) ◽  
pp. R1160-R1163 ◽  
Author(s):  
B. T. Firth ◽  
M. B. Thompson ◽  
D. J. Kennaway ◽  
I. Belan
Keyword(s):  
Environmental Conditions ◽  
Thermal Sensitivity ◽  
Cold Temperature ◽  
Daily Rhythm ◽  
Threshold Temperature ◽  
Daily Rhythms ◽  
Thermoregulatory Behavior ◽  
Lower Amplitude ◽  
Sphenodon Punctatus ◽  
Reptilian Species

Daily rhythms in plasma melatonin levels were compared in two ecologically diverse reptilian species under natural environmental conditions in autumn. The nocturnal, cold temperature-adapted tuatara (Sphenodon punctatus) had a melatonin rhythm of much lower amplitude than did the diurnal desert-adapted sleepy lizard (Tiliqua rugosa). Experiments in controlled laboratory environments showed that, although both species are capable of attaining a comparable melatonin peak (approximately 750 pmol/l), the threshold temperature at which a significant daily rhythm occurs is approximately 15 degrees C in S. punctatus compared with approximately 25 degrees C in T. rugosa. This difference probably reflects the disparate thermoregulatory adaptations of the two species, S. punctatus favoring mean activity temperatures of 11.5 degrees C and T. rugosa, 32.5 degrees C. In ectotherms such as reptiles, therefore, species-typical thermoregulatory behavior may provide thermal cues that interact with photoperiod to provide the appropriate melatonin signal for the regulation of annual physiological cycles.

scholarly journals Thermal limits for flight activity of field-collected Culicoides in the United Kingdom defined under laboratory conditions

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Laura A. Tugwell ◽  
Marion E. England ◽  
Simon Gubbins ◽  
Christopher J. Sanders ◽  
Jessica E. Stokes ◽  
...  
Keyword(s):  
Companion Animals ◽  
Flight Activity ◽  
Cold Temperature ◽  
Threshold Temperature ◽  
Thermal Limits ◽  
Laboratory Conditions ◽  
North East ◽  
Temperature Thresholds ◽  
South East England ◽  
The Uk

Abstract Background Culicoides biting midges (Diptera: Ceratopogonidae) are biological vectors of internationally important arboviruses and inflict biting nuisance on humans, companion animals and livestock. In temperate regions, transmission of arboviruses is limited by temperature thresholds, in both replication and dissemination of arboviruses within the vector and in the flight activity of adult Culicoides. This study aims to determine the cold-temperature thresholds for flight activity of Culicoides from the UK under laboratory conditions. Methods Over 18,000 Culicoides adults were collected from the field using 4 W down-draught miniature ultraviolet Centers for Disease Control traps. Populations of Culicoides were sampled at three different geographical locations within the UK during the summer months and again in the autumn at one geographical location. Activity at constant temperatures was assessed using a bioassay that detected movement of adult Culicoides towards an ultraviolet light source over a 24-h period. Results The proportion of active adult Culicoides increased with temperature but cold temperature thresholds for activity varied significantly according to collection season and location. Populations dominated by the subgenus Avaritia collected in South East England had a lower activity threshold temperature in the autumn (4 °C) compared with populations collected in the summer (10 °C). Within the subgenus Avaritia, Culicoides scoticus was significantly more active across all temperatures tested than Culicoides obsoletus within the experimental setup. Populations of Culicoides impunctatus collected in the North East of England were only active once temperatures reached 14 °C. Preliminary data suggested flight activity of the subgenus Avaritia does not differ between populations in South East England and those in the Scottish Borders. Conclusions These findings demonstrate seasonal changes in temperature thresholds for flight and across different populations of Culicoides. These data, alongside that defining thresholds for virus replication within Culicoides, provide a primary tool for risk assessment of arbovirus transmission in temperate regions. In addition, the study also provides a comparison with thermal limits derived directly from light-suction trapping data, which is currently used as the main method to define adult Culicoides activity during surveillance.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: II. SURFACE TEMPERATURE, VASCULARIZATION, AND IN VITRO RESPIRATION OF THE SKIN

1959 ◽  
Vol 37 (1) ◽  
pp. 1247-1253 ◽  
Author(s):  
O. Héroux
Keyword(s):  
Oxygen Uptake ◽  
Surface Temperature ◽  
Respiratory Rate ◽  
Environmental Conditions ◽  
Cold Temperature ◽  
Dorsal Skin ◽  
Adult Rats ◽  
White Rats ◽  
Different Types

The effect of cold temperature on the skin was studied on white rats exposed to two different types of environmental conditions. Two groups of adult rats kept in individual cages were continuously exposed for 3 months to constant cold temperature (18° and 6 °C) in the laboratory (indoor rats) while other groups of the same colony kept in groups of 10 were exposed for the same length of time to the fluctuating environmental conditions prevailing outside (outdoor rats).Indoor rats acclimated to 18 °C and 6 °C showed the same increase in the number of opened capillaries in the ears over the number observed in controls acclimated to 30 °C. "Summer and winter" outdoor rats showed the same number of capillaries as the "18 °C or 6 °C" indoor rats. Signs of injury healing such as thicker epidermis and larger nuclei were found in the ears of all the "6 °C" rats but in none of the "winter" rats. While the skin temperature measured at + 6 °C was slightly higher (0.4 to 1.0 °C) in rats acclimated at 6 °C than in those at 30 °C, it was lower (1.3 to 2.9 °C) in "winter" than in "summer" rats. After 28 days of acclimation, the rate of oxygen uptake of the dorsal skin of the foot was lower in "6 °C" than in "30 °C" rats but after 84 days it was significantly higher in the cold-acclimated rats. Similarly, after 3 months, the respiratory rate of the dorsal skin of the foot was higher in "winter" rats than in "summer" rats.

scholarly journals Cold temperature represses daily rhythms in the liver transcriptome of a stenothermal teleost under decreasing day length

2018 ◽  
Vol 221 (5) ◽  
pp. jeb170670 ◽  
Author(s):  
Jenni M. Prokkola ◽  
Mikko Nikinmaa ◽  
Mario Lewis ◽  
Katja Anttila ◽  
Mirella Kanerva ◽  
...  
Keyword(s):  
Cold Temperature ◽  
Day Length ◽  
Daily Rhythms ◽  
Liver Transcriptome

Daily rhythms of acute phase proteins in cattle under different natural environmental conditions

2012 ◽  
Vol 149 (1-2) ◽  
pp. 195-200 ◽  
Author(s):  
Claudia Giannetto ◽  
Stefania Casella ◽  
Elisabetta Giudice ◽  
Simona Marafioti ◽  
Francesco Fazio ◽  
...  
Keyword(s):  
Acute Phase ◽  
Environmental Conditions ◽  
Acute Phase Proteins ◽  
Daily Rhythms

Time-restricted feeding entrains daily rhythms of energy metabolism in mice

2006 ◽  
Vol 290 (5) ◽  
pp. R1276-R1283 ◽  
Author(s):  
Yoko Satoh ◽  
Hiroshi Kawai ◽  
Naomi Kudo ◽  
Yoichi Kawashima ◽  
Atsushi Mitsumoto
Keyword(s):  
Energy Metabolism ◽  
Clock Genes ◽  
Expression Patterns ◽  
Daily Rhythm ◽  
Dark Phase ◽  
Restricted Feeding ◽  
Daily Rhythms ◽  
Peripheral Tissues ◽  
Temperature Rhythm ◽  
Ad Libitum

Energy metabolism, oxygen consumption rate (V̇o2), and respiratory quotient (RQ) in mice were monitored continuously throughout 12:12-h light-dark cycles before, during, and after time-restricted feeding (RF). Mice fed ad libitum showed robust daily rhythms in both parameters: high during the dark phase and low during the light phase. The daily profile of energy metabolism in mice under daytime-only feeding was reversed at the beginning of the first fasting night. A few days after daytime-only feeding began, RF also reversed the circadian core body temperature rhythm. Moreover, RF for 6 consecutive days shifted the phases of circadian expression patterns of clock genes in liver significantly by 8–10 h. When mice were fed a high-fat (HF) diet ad libitum, the daily rhythm of RQ dampened day by day and disappeared on the sixth day of RF, whereas V̇o2 showed a robust daily rhythm. Mice fed HF only in the daytime had reversed V̇o2 and RQ rhythms. Similarly, mice fed HF only in the daytime significantly phase shifted the clock gene expression in liver, whereas ad libitum feeding with HF had no significant effect on the expression phases of liver clock genes. These results suggested that V̇o2 is a sensitive indicator of entrainment in the mouse liver. Moreover, physiologically, it can be determined without any surgery or constraint. On the basis of these results, we hypothesize that a change in the daily V̇o2 rhythm, independent of the energy source, might drive phase shifts of circadian oscillators in peripheral tissues, at least in the liver.

Daily rhythms of lipogenesis in fat and lean white-throated sparrows Zonotrichia albicollis.

1977 ◽  
Vol 232 (2) ◽  
pp. E193 ◽  
Author(s):  
A H Meier
Keyword(s):  
Body Fat ◽  
Liver Lipid ◽  
The Body ◽  
Daily Rhythm ◽  
Temporal Relations ◽  
Body Lipid ◽  
Daily Rhythms ◽  
Zonotrichia Albicollis ◽  
Fat Stores ◽  
Apparent Influence

Lipogenesis was assayed at 6 times a day in the migratory white-throated sparrow Zonotrichia albicollis by measuring the incorporation of label in liver and body lipid 4 h after injection of [3H] acetate. There were daily rhythms of 3H incorporation by liver lipid both in fat birds in the vernal migratory condition and in lean birds in the summer photorefractory condition. Most of the liver lipid incorporation of 3H was restricted to the late afternoon and early evening in both the fat and lean birds. In addition, the total liver incorporation was similar for both groups. On the other hand, nearly twice as much 3H was incorporated in the body lipid of fat birds as in that of lean birds, and a daily rhythm was present only in fat sparrows. Injections of prolactin given simultaneously with [3H] acetate early during the day (at a time when daily injections of the hormone can cause severe losses in body fat stores) drastically reduces liver and body lipid incorporation of 3H. However, injections of prolactin during the afternoon (when daily injections of the hormone produce large increases in body fat stores) have no apparent influence on the incorporation of label. Our results indicate that a principal difference between lean and fat birds resides in a greater capacity in fat birds to transport triglycerides from the liver, in which they are produced, to the body storage depots. The daily rhythm of prolactin in some temporal relations may cause fattening by increasing the transport capacity or cause loss in fat stores in other temporal relations by directly inhibiting hepatic lipogenesis.

COMPARISON BETWEEN SEASONAL AND THERMAL ACCLIMATION IN WHITE RATS: I. METABOLIC AND INSULATIVE CHANGES

1959 ◽  
Vol 37 (3) ◽  
pp. 473-478 ◽  
Author(s):  
O. Héroux ◽  
F. Depocas ◽  
J. S. Hart
Keyword(s):  
Metabolic Rate ◽  
Constant Temperature ◽  
Environmental Conditions ◽  
Resting Metabolic Rate ◽  
Thermal Acclimation ◽  
Cold Temperature ◽  
Metabolic Rates ◽  
Temperature Range ◽  
White Rats ◽  
Physiological Adjustments

Physiological adjustments to cold temperature have been compared in white rats exposed either to the outdoor fluctuating environmental conditions or to the indoor constant temperature conditions. While the metabolic adjustments such as increased peak metabolism and decreased shivering were similar in outdoor and indoor rats exposed to cold, the adjustments in insulation and thermoneutral metabolic rates were quite different. The pelage insulation increased in the rats kept outside during the winter but remained unchanged in the rats kept in a constant temperature room maintained at 6 °C. The resting metabolic rate measured at 30 °C increased in the 6 °C acclimated rats but not in the winter-exposed animals. Over the temperature range +30 °C to −15 °C, while the indoor cold-acclimated rats had a higher metabolic rate than their controls acclimated to 30 °C, the winter rats had a lower metabolism than their summer controls.

Vestibular loss disrupts daily rhythm in rats

2015 ◽  
Vol 118 (3) ◽  
pp. 310-318 ◽  
Author(s):  
T. Martin ◽  
B. Mauvieux ◽  
J. Bulla ◽  
G. Quarck ◽  
D. Davenne ◽  
...  
Keyword(s):  
Daily Rhythm ◽  
Control Group ◽  
Vestibular Input ◽  
Daily Rhythms ◽  
Cell Degeneration ◽  
Vestibular Loss ◽  
Anatomical Structures ◽  
Bilateral Vestibular Loss ◽  
Vestibular Lesion ◽  
Vestibular Pathology

Hypergravity disrupts the circadian regulation of temperature (Temp) and locomotor activity (Act) mediated through the vestibular otolithic system in mice. In contrast, we do not know whether the anatomical structures associated with vestibular input are crucial for circadian rhythm regulation at 1 G on Earth. In the present study we observed the effects of bilateral vestibular loss (BVL) on the daily rhythms of Temp and Act in semipigmented rats. Our model of vestibular lesion allowed for selective peripheral hair cell degeneration without any other damage. Rats with BVL exhibited a disruption in their daily rhythms (Temp and Act), which were replaced by a main ultradian period (τ <20 h) for 115.8 ± 68.6 h after vestibular lesion compared with rats in the control group. Daily rhythms of Temp and Act in rats with BVL recovered within 1 wk, probably counterbalanced by photic and other nonphotic time cues. No correlation was found between Temp and Act daily rhythms after vestibular lesion in rats with BVL, suggesting a direct influence of vestibular input on the suprachiasmatic nucleus. Our findings support the hypothesis that the vestibular system has an influence on daily rhythm homeostasis in semipigmented rats on Earth, and raise the question of whether daily rhythms might be altered due to vestibular pathology in humans.

The influence of plant raising conditions on the head weight of crisp lettuce at maturity

1982 ◽  
Vol 99 (2) ◽  
pp. 417-423 ◽  
Author(s):  
D. C. E. Wurr ◽  
Jane R. Fellows
Keyword(s):  
Environmental Conditions ◽  
Coefficient Of Variation ◽  
Artificial Lighting ◽  
Lower Amplitude ◽  
Head Weight ◽  
Similar Weight ◽  
Supplementary Lighting ◽  
And Tungsten

SUMMARYTwo experiments investigated the effects of raising crisp lettuce seedlings under different environmental conditions prior to transplanting, on transplant size and weight and head weight at maturity.The use of tungsten lighting for 4 h after the end of a 12 h period of fluorescent and tungsten lighting increased transplant size and weight and the weight of heads at maturity compared with fluorescent and tungsten lighting only. Glasshouse-raised transplants were larger than those raised under artificial lighting but gave heads of similar weight to transplants which had supplementary tungsten lighting for 2 weeks. Both these treatments gave significantly heavier heads than a drilled crop or plants raised without supplementary tungsten lighting. Increasing the number of weeks of the supplementary lighting treatment tended to increase the coefficient of variation (c.v.) of head weight. Nevertheless the drilled crop had a higher c.v. of head weight than any transplanted treatment.The variety Pennlake produced pointed (‘coned’) heads when grown in the open and its leaves were shorter and broader than those of plants grown in polyethylene tunnels, which did not show ‘coning’. It is suggested that ‘coning’ occurs primarily as a result of either lower mean temperatures or a lower amplitude of temperature when grown in the open. It occurred most frequently with glasshouse-raised plants indicating that a higher raising temperature may also contribute to the problem.

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