Behavioural thermoregulation and critical thermal limits of Macrobrachium acanthurus (Wiegman)

• (1)The preferred temperatures of Macrobrachium acanthurus were determined for prawns acclimated to 20°C, 23°C, 26°C, 29°C and 32°C, and the final preferendum estimate was (29.5°C).
• (2)The critical thermal minima (CTMin) and maxima (CTMax) were 11.0°C, 12.1°C, 13.0°C and 14.8°C, and 34.2°C, 35.0°C, 36.1°C and 39.8°C, respectively.
• (3)The zone of thermal tolerance assessed using the CTMin and CTMax boundaries was 644°C².
• (4)The acclimation response ratio was between 0.33 and 0.62.
• (5)To cultivate this species in the southeastern region of México it should be done in not <15°C (CTMin) during the winter and below 38°C in summer (CTMax).

     

Temperature acclimation in respiratory and cytochrome c oxidase activity in common carp (Cyprinus carpio)

• 1.1. Common carp (Cyprinus carpio) exposed to experimental temperatures of 12, 18, 24, 30 or 36°C for a 4-week period were used to investigate the effect of temperature acclimation on the frequency of opercular movement (FOM), growth and cytochrome c oxidase (CCO) activity in heart, liver and muscle.
• 2.2. An exponential relationship between FOM and temperature after the first week (10₁₀ =1.76) disappeared after the second week.
• 3.3. The initially high FOM at temperatures of 30 or 36°C and the low FOM at 18 or 12°C changed over 4 weeks to approach the FOM of fish at 24°C.
• 4.4. This change in the relationship of FOM to temperature from highly dependent to independent appeared to be thermal compensation.
• 5.5. Heart and liver CCO activities were significantly affected by temperature, with the lowest activity at the approximate optimum temperature for growth, 24°C.
• 6.6. Highest CCO activities for heart and liver occurred at both the highest and lowest temperatures.
• 7.7. Among the three tissues, heart CCO activity was generally the highest and most affected by acclimation temperature.
• 8.8. Muscle tissue had the lowest CCO activity and was unaffected by temperature.
• 9.9. The high CCO activity at a cold acclimation of temperature 12°C was probably due to thermal compensation and the high activity at 36°C may have been a result of thermal stress.

     

Effects of acclimation temperature,season, and time of day on the critical thermal maxima and minima of the crayfish Orconectes rusticus

• 1.1. The critical thermal minima (CTMin) and maxima (CTMax) were determined for field-acclimatized and laboratory-acclimated crayfish (Orconectes rusticus) throughout 1984.
• 2.2. The CTMin and CTMax of field-acclimatized crayfish were seasonally adjusted by 9.7 C and 14.7 C respectively.
• 3.3. Seasonal variation in both tolerance regimes persisted in crayfish acclimated in the laboratory at 5 and 25°C for one week; however, no diel variation existed in either the CTMin or CTMax of laboratory-acclimated crayfish.
• 4.4. Integration of thermal acclimation of the CTMin and CTMax with seasonal conditioning may influence the functional capacities of this species when considered in relation to the seasonal ranges in stream temperature.

     

Effect of temperature on oxygen consumption and heart rate of the australian crayfish Cherax tenuimanus (Smith)

• 1.1. Oxygen consumption at 18°C was 60% of the rate at 22 and 26°C.
• 2.2. Critical points, where the rate of oxygen consumption changed, were defined at 22°C (2.89 mg DO) and 26°C (3.46 mg DO). Linear regressions were fitted showing that oxygen consumption declined significantly (81.5% ±4.5) below the critical point.
• 3.3. Oxygen consumption was proportional to weight. Allometric relationships resulted in variable temperature-related coefficients for respiratory dependence on weight, a reflection of the crayfish adaptation towards re-establishment of a new equilibrium state.
• 4.4. Heart beat rate was lower at 18°C, and highest at the acclimation temperature (22°C). Stress at 26°C was evident.

     

Physically modeling operative temperatures and evaporation rates in amphibians

• (1)We designed a physical model that simulates the thermal and evaporative properties of live Western toads (Bufo boreas).
• (2)In controlled tests, the model tracked the body temperature of live toads with an average error of 0.3±0.03 °C (test range=4–30 °C).
• (3)It estimated the evaporative water loss of live toads with an average error of 0.35–0.65  g/h, or about 14% (test range=0.7–9 g/h).
• (4)Data collected with this physical model should provide an effective way for biologists to better understand habitat selection in toads and other amphibians

     

Behavior of the terrestrial nocturnal lizards Goniurosaurus kuroiwae kuroiwae and Eublepharis macularius (Reptilia: Eublepharidae) in a thigmothermal gradient

• 1.Two eublepharid gecko species were tested for their thermal preferences in a thigmothermal gradient.
• 2.Goniurosaurus kuroiwae kuroiwae from a humid subtropical Oriental forest selected a lower body temperature (Tp; average 16.6 °C) than Eublepharis macularius from an arid Palaearctic area (25.8 °C).
• 3.Both the locations of animals along the gradient and the Tp were significantly more variable among G. k. kuroiwae than among E. macularius.
• 4.There were no significant differences in Tp and in its variance between photophase and scotophase in either species.

     

Determination of temperature preference and the role of the enlarged cheliped in thermoregulation in male sand fiddler crabs,Uca pugilator

• 1.Male Uca pugilator whose major cheliped was immersed in 3 °C water bath experienced a significant drop in T_b. Thus, the enlarged claw of male Uca pugilator may have an unexplored function: thermoregulation.
• 2.Crabs prefer warmer substrates (19–24 and 28–30 °C) over cooler (15–17 °C).
• 3.Mean selected temperature (MST) may not be an accurate reflection of T_b. Crabs in a thermal chamber preferred temperatures between 25 and 30 °C but their average T_b was 23.2 °C.

     

Cold tolerance of steinernematid and heterorhabditid nematodes

• 1.1. Nematodes survive subzero temperatures using either a freeze-avoiding or freezing-tolerant strategy. Steinernema anomali, S. feltiae, and Heterorhabditis bacteriophora were all found to be freezing tolerant.
• 2.2. The lower lethal temperatures were −22, −19 and −14°C for S. feltiae, H. bacteriophora and S. anomali, respectively.
• 3.3. Survival after prolonged freezing at −4°C was 6, 5 and 3 days for S. feltiae, H. bacteriophora and S. anomali, respectively.
• 4.4. Acclimation to lower temperatures increased freezing tolerance. The freezing tolerance of Heterorhabditis bacteriophora increased under a stepwise acclimation regime; S. feltiae acclimated better under a direct acclimation regime.

     

Heating and cooling rates of eastern diamondback rattlesnakes,Crotalus adamanteus

• 1.Establishing if and how organisms modulate temperature changes is an important component of understanding their thermal biology.
• 2.We used temperature-sensitive radio-transmitters to monitor heating and cooling rates between 5 and 35 °C of four Crotalus adamanteus in the laboratory.
• 3.We found no difference between heating and cooling rates in C. adamanteus. Additionally, rates of temperature change mirrored those of a biophysical model, further suggesting a lack of physiological thermoregulation.
• 4.Our findings contrast previously published studies that demonstrate active temperature control of similarly sized reptiles and demonstrate a need for more investigations of physiological thermoregulation in reptiles.

     

Thermotolerance and thermal sensitization in a differentiating murine erythroleukemia cell line

• 1.1.|Friend erythroleukemia cells (FELC, a differentiating cell line) were heated at various temperatures and heating sequences. Heat treatments which ranged from 41.0 to 45.0°C and did not cause differentiation in FELC and inhibited the differentiation response to DMSO in FELC.
• 2.2.|Heating resulted in cell killing which increased with temperature and heating time. Protracted low temperature heating (40.0–42.0°C) or incubation at 37°C between two heat treatments at 45.0°C resulted in thermotolerance for both the endpoints of cell killing and differentiation.
• 3.3.|High temperature heating (45.0°C) before heating at 41.0–42.0°C resulted in increased thermal sensitivity to the latter heat treatments. This was observed for both the survival and differentiation endpoints.
• 4.4.|A comparison was made of the thermal sensitivity for the two endpoints of cell killing and differentiation.

     

Heart rate and its cholinergic control in the sole (Solea vulgaris), acclimatized to different temperatures

• 1.1. The effects of thermal acclimatization at 10 and 24°C on heart rate were investigated on unrestrained soles (Solea vulgaris).
• 2.2. The sensitivity of heart rate to temperature changes induced by temperature acclimatization was higher in cold-acclimatized than in warm-acclimatized soles.
• 3.3. Heart rate of cold-acclimatized fish to temperature changes was not affected by blocking the vagal tone with atropine.
• 4.4. After atropine treatment the ability of heart rate to show thermal compensation decreased in warm-acclimatized soles.
• 5.5. It is suggested that the vagus nerve can function differently at different temperatures.

     

The electrophoretic patterns of glucose-6-phosphate, 6-phosphogluconate and glucose dehydrogenases in Amoeba proteus (Pallas, 1766) Leidy, 1878 cultured at different temperatures

• 1.1. The detection of G6PD and 6PGD in A. proteus can be used to investigate the functioning of the phosphogluconic (or pentose phosphate) pathway in these amoebae.
• 2.2. In amoebae cultured at 10°C compared with those kept at 25°C, no differences in the number of G6PD, 6PGD and GlcDH electromorphs are revealed.
• 3.3. The acclimation of amoebae cultured at 25°C to a relatively low temperature of 10°C is accompanied by an increase in the activities of total Triton-soluble G6PD, 6PGD and GlcDH per cell, a rise in the activity of GlcDH per unit cell protein, and a change in the activity and heat resistance of some G6PD electromorphs.

     

Influence of environmental factors on the deep and skin temperature in the European bison,Bison bonasus (L.)

• 1.1. In 43 European bison divided into three groups (Group A, 3–8-month-old calves; Group B, 18-month-7-year-old young bison; Group C, 12–24-year-old bison) the rectal, humerus region and abdomen region temperatures were measured.
• 2.2. The experiments were carried out in winter months, from mid-December to mid-March.
• 3.3. The mean rectal temperatures changed from 38.55°C in calves to 38.15°C in the oldest bison.
• 4.4. The mean temperatures of the humerus region changed from 20.69°C in calves to 21.49°C in older bison.
• 5.5. The mean temperatures of the abdomen region changed from 20.79°C in calves to 22.17°C in older bison (Gr. B).
• 6.6. The cluster analysis divided the bison into four groups named hot, warm, cool and cold bison.
• 7.7. Only air temperature measured 2 m above the ground and snow cover influenced the integrated bison temperature. Age, sex and mass as well as some environmental factors had no influence.
• 8.8. Measurements made 1 to nearly 4hr after a bison's death showed a drop in rectal temperature and mostly increases in temperatures of the humerus and abdomen regions.

     

Effect of temperature and salinity on the oxygen consumption of laboratory produced Penaeus californiensis postlarvae

• 1.1. The oxygen consumption by P. californiensis postlarvae (mean wt = 0.38 g) was determined at five different temperatures and four salinities.
• 2.2. The O₂ in each chamber was recorded at 10 min intervals for 1 hr. The time course of oxygen depletion was independent of O₂ concentration down to 1.6 mg/l.
• 3.3. Oxygen consumption increased with temperature from 0.0045 mg/g/min at 19°C, to 0.0142 mg/g/min at 35°C. The thermal coefficient (Q₁₀) indicated a very high sensitivity of the postlarvae to temperature variations at 19–23°C.
• 4.4. The results show that oxygen consumption significantly depends on temperature (P < 0.001) while salinity has only a marginal effect.

     

Effect of acute temperature change on lung respiration of the mollusc Lymnaea stagnalis

• 1.Temperature-dependent effects on respiratory behaviour as well as the corresponding temperature-dependent activities of identified neurons within the respiratory network of the pulmonate snail Lymnaea stagnalis were investigated.
• 2.Lymnaea lung ventilation terminated at low temperatures (under 10 °C) while temperature elevation increased ventilation rates. The respiratory central pattern generator (CPG) functioning was relatively quiescent at temperatures under 12.5±0.44 °C.
• 3.Identified CPG neurons (RPeD1, VD4, VD1/RPaD2) and the respiratory network motor neurons (Vi- and RPa-cells) were found to exhibit varied temperature-dependent electrophysiological parameters (action potential frequency and amplitude, resting potential value) between cell types.
• 4.The observed alterations in the electrical activity of the Lymnaea respiratory network neurons underlie the marked changes of respiratory behaviour observed in the intact animal during temperature changes.

     

Effects of temperature and metabolic inhibitors on contraction of anterior byssus retractor muscle of Mytilus

• 1.1. Anterior byssus retractor muscle of Mytilus (ABRM) was stimulated to contract by ACh (acetylcholine) and effects of temperature (5–30°C), FDNB (1-fluoro 2,4 dinitro-benzene) and IAA (iodoacetic acid) on tension response were examined.
• 2.2. Isometric tension was highest at the temperature range of 10–20°C and decreased at higher and lower temperature than that range.
• 3.3. The rate of tension decay after washing of ACh was accelerated by the increase of temperature.
• 4.4. Tension redevelopment after release of 1 % during contraction was much smaller at 5°C than at 20°C.
• 5.5. Tension development by ACh and the rate of tension decay after washing of ACh were remarkably decreased by the treatment of FDNB or IAA.
• 6.6. The above results were discussed from the viewpoint that energy metabolism might be related to catch.

     

Proteome-wide Analysis of Protein Thermal Stability in the Model Higher Plant Arabidopsis thaliana

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Highlights

• •Over 1700 Arabidopsis proteins with thermal models in multiple replicates.
• •Melting temperature correlates with 1°, 2°, and 3° protein characteristics.
• •Ligand-induced thermal shifts are evident in complex protein extracts.

     

Effects of low environmental pH and temperature on hatching and metabolic rates in embryos of Anax junius drury (Odonata: Aeshnidae) and the role of hypoxia in the hatching process

• 1.1. Studies were conducted in order to determine the combined effects of low environmental pH and temperature on embryonic survival capacity and metabolic rates in the dragonfly, Anax junius Drury. Studies were also conducted to assess the effects of hypoxia on hatching success as well as to investigate the role of hypoxia as a possible physiological triggering mechanism for hatching.
• 2.2. At water temperatures of 10–30°C, an environmental pH value of 3.0 was extremely limiting and significantly reduced hatching success.
• 3.3. Over a pH range of 3.0–5.0, a water temperature of 30°C was found to be severely limiting. Over a pH range of 6.0–7.0, hatching success was greater than 80% at test temperatures ranging from 10 to 25°C.
• 4.4. Embryos of A. junius exhibited a greater tolerance to markedly low environmental pH (3.0) than that previously reported for fish and amphibians, although survival capacity was less than 10%.
• 5.5. An environmental pH value of 3.0 has a significant detrimental effect on embryonic development. Survivorship and developmental rate increase significantly over a pH range of 4.0–5.0.
• 6.6. Oxygen consumption rates were lowest for fertilized eggs exposed to a pH of 3.0 at all test temperatures (10–30°C). Metabolic rates increased significantly at pH 4.O.
• 7.7. Embryos hatch successfully under hypoxic conditions in both aqueous and nonaqueous media. Results suggest that hypoxia acts as a triggering mechanism for hatching in this aquatic insect.

     

Thermal acclimation of metabolism and preferred body temperature in lizards

• 1.1.|The standard metabolic rates (SMRs) and preferred body temperatures (PBTs) of the tropical cordylid Cordylus jonesi and temperature lacertid Lacerta lilfordi were determined following acclimation to constant environmental temperatures of 20 and 30°C.
• 2.2.|Although after 5 weeks the SMRs of Cordylus jonesi and Lacerta lilfordi displayed partial compensations of 20.9 and 10.5%, respectively, their PBTs did not alter over this period. Therefore, acclimation does not maintain complete metabolic homeostasis during either the active or inactive phase of the lizard.
• 3.3.|Cordylus jonesi allowed to thermoregulate behaviourally at their PBT during activity possessed similar SMRs to control animals maintained continually at the same background temperatures, indicating that acclimation state in lizards is determined by the body temperatures experienced while at rest.
• 4.4.|The particular acclimatory problems of animals exhibiting behavioural homeothermy are discussed.

     

Transfer system of cobalamin from pellicle to cytosolic binding proteins in Euglena gracilis

• 1.1. A cobalamin (Cb1)-transfer system from the pellicle to cytosolic Cb1-binding proteins occurs in Euglena gracilis.
• 2.2. The Cbl-transfer activity showed thermal dependency. The optimum temperature was 50°C. The Cbl-transfer activity was increased significantly above pH 7.0.
• 3.3. ATPase, thiol-groups and metal ions were not involved in the Cbl transfer.