The influence of aerial exposure on gas exchange and cardiac activity in the shore crab,Carcinus maenas (L.)

• 1.1. The cardiovascular physiology of adult Carcinus maenas (L.) emerging into air has been investigated at three different air temperatures.
• 2.2. Transition from seawater to air or vice versa triggered transient increases in cardiac and locomotor activity.
• 3.3. However, crabs became inactive 5–10 min after emerging from seawater (15°C) into air at the same temperature (15°C) or at lower temperatures (12–13°C) and heart rate fell.
• 4.4. At higher air temperatures (18–20°C) heart rate rose but to a lesser extent than predicted from aquatic Q₁₀ heart-rate values.
• 5.5. Crabs were again quiescent in aerial conditions.
• 6.6. Mean arterial oxygen tension (Pa_o2) was ~ 74 mmHg in submerged crabs but fell to ~ 38 mmHg in air while mean arterial carbon dioxide tension (Pa_o2) increased from 1 to 4 mmHg resulting in respiratory acidosis.
• 7.7. A model of gill function is proposed to explain the development of internal hypoxia in air.
• 8.8. The results are discussed in relation to the distribution of adult and juvenile C. maenas in situ.

     

Compensations for temperature in the activities of digestive enzymes of Periplan eta americana (L.)

• 1.1. Differential thermal acclimatory responses of maximal catalytic rates (V_max) of digestive enzymes have been measured in both sexes of Periplaneta americana adapted to 16 and 32°C.
• 2.2. Salivary amylase of females and gastric protease of males exhibit “translational” acclimation, the former showing a “complete” but the latter only a “partial” compensation. The value of Q₁₀ is not altered in the adaptive response.
• 3.3. An alteration of the thermal coefficient is evidenced by the “translational-cum-rotational” compensation of gastric amylolytic activity, with significant warm acclimation but no cold acclimation in both sexes.
• 4.4. Gastric protease of female cockroaches and gastric lipase of both sexes are characterized by the lack of an adaptive compensation to temperature, while salivary amylase of male appears to manifest an “inverse” acclimation.
• 5.5. Sexual dimorphism in the levels of the activities and in the patterns of thermal acclimation of the digestive enzymes is indicated.

     

Hypothermia and blood of crabs

• 1.1. The effect of acclimation to 10° and 30°C on the blood volume, clotting time, total blood protein and numbers of cells was determined in Uca pugilator.
• 2.2. There was no significant difference between blood volume in the 10° and 30° animals but there were significantly more cells and a higher blood protein in the 30° crabs.
• 3.3. The clotting time is significantly longer for the 10° crabs.
• 4.4. These changes associated with the blood parameters can be associated with the ecology of the animal.

     

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.

     

Metabolic rate and body temperature of adult and juvenile hyrax (Procavia capensis)

• 1.1. Resting metabolic rates (RMR) below thermoneutrality in adult hyrax acclimated to 26, 15 and 10°C remained unchanged, i.e. thermal conductance (K) remained constant.
• 2.2. Conductance in juveniles decreased with acclimation to lower ambient temperatures (T_a).
• 3.3. Body temperature (T_b) dropped by 3.8°C in adults exposed to T_a of 30 – 5°C. The decrease was constant.
• 4.4. Body temperature fell by 1.5°C in juveniles exposed to T_a of 30 – 20°C but stabilized between 20 and 5°C.
• 5.5. The labile T_b, associated with behavioural strategies and lower than predicted RMR, can be seen as an energy-conserving mechanism of particular importance during winter conditions.

     

The dependence of oxygen consumption of the common whelk (Buccinum undatum) on hypoxia,salinity and air exposure

• 1.1. Oxygen consumption of low salinity (20‰) acclimated whelks decreases markedly upon acute exposure to hypoxia (P_WO₂ = 35 Torr), but almost regenerates its original level within 48 hr exposure to the hypoxic condition.
• 2.2. This ability to regain the original level of oxygen consumption is not seen in high salinity (35‰) acclimated whelks.
• 3.3. Oxygen consumption in air at 10°C is more than twice the rate shown by low salinity acclimated whelks in normoxic water (P_WO₂ = 150 Torr).
• 4.4. Q₁₀ for oxygen consumption in air is about 1.0 in the temperature range 10–20°C.

     

Modification of glyceraldehyde-3-phosphate dehydrogenase,EC 1.2.1.12, isolated from rainbow trout during acclimation at 5 or 15°C—I. Changes in the activity of individual muscle isolates as evidence for variable adaptive responses

• 1.1. The mean K_m and V_max values for G3PDH isolated from the lateral muscle of cold-adapted (5°C) rainbow trout, Salmo gairdneri, were twice those of enzyme from warm-adapted (15°C) trout when assayed at 7°C but not at any other temperature.
• 2.2. The entropy of activation of warm enzyme was about 3 times that of cold enzyme. However, enthalpy or free energy of activation among acclimation groups differed less or not at all.
• 3.3. Individual G3PDH isolates within either adaptation group differed in kinetic characteristics.

     

Lactate dehydrogenase of goldfish red and white muscle in relation to thermal accumulation

• 1.1. Activities of the red and white muscle LDH from 8°C-acclimated goldfish were about three times higher than those acclimated to 28°C.
• 2.2. Isozyme composition and some kinetic properties of the red muscle LDH differed from those of the white muscle enzyme.
• 3.3. The amount of red muscle as well as LDH activity tended to increase during cold acclimation.

     

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).

     

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.

     

Modification of glyceraldehyde-3-phosphate dehydrogenase,EC 1.2.1.12, isolated from rainbow trout during acclimation at 5 or 15°C—II. Biochemical characterization of G3PDH muscle isolates

• 1.1. G3PDH was isolated from the lateral muscle of rainbow trout (Salmo gairdneri) acclimated at 5°C (cold) and 15°C (warm).
• 2.2. No differences were found in muscle concentration, molecular weights, isoelectric focusing patterns, amino acid compositions or peptide maps between cold and warm isolates.
• 3.3. Cold and warm G3PDH contained mannose in variable concentration but no other prosthetic groups.

     

The influences of individual variations in metabolic rate and tidal conditions on the response to hypoxia in Carcinus maenas (L.)

• 1.1. The oxygen consumption of crabs in normoxic and hypoxic (50% O₂) seawater was measured directly after collection.
• 2.2. The influences of size and lunar cycles were removed by scaling the data.
• 3.3. Strong negative correlations between low individual levels of O₂ consumption and the ability to compensate for hypoxia were apparent in Wicklow (subtidal) crabs.
• 4.4. Compensation for hypoxia was much greater on the flood tide than on the ebb.
• 5.5. Crabs from Roscoff (intertidal) had lower levels of compensation than those from Wicklow.
• 6.6. Size, sex and condition had no apparent effect upon these relationships.
• 7.7. Crabs acclimated to laboratory conditions have not shown this tidal variation in compensation for hypoxia.

     

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.

     

Effects of altitude on selected blood parameters in populations of the salamander Ambystoma macrodactylum

• 1.1. Adult long-toed salamanders were collected from three sites ranging in elevation from 420 to 2470 m and acclimated at 800 and 2400 m.
• 2.2. Variations in hemoglobin concentration (Hb) and hematocrit (Hct) among populations were analyzed.
• 3.3. Differences among populations were significant in the 800 m acclimation group but not those acclimated at 2400 m.
• 4.4. Significant increases in Hct were associated with acclimation at a higher elevation but concurrent increases in Hb were not observed.

     

Effect of warm acclimation on the cationic concentrations in the extracellular and intracellular body fluid of hibernating Rhagium inquisitor beetles

• 1.1. The effect of warm acclimation on the cationic concentrations of hibernating Rhagium inquisitor beetles was studied.
• 2.2. Following warm acclimation, the extracellular concentration of Mg²⁺ dropped from about 80 to about 50 mM. For Na⁺ and K⁺ the extracellular concentration remained constant at about 40 mM. The estimated intracellular concentration of Mg²⁺ was not affected by the warm acclimation, being about 80 mM in both groups of beetles. The corresponding concentration of Na⁺ increased from about 20 to about 30 mM, whereas for K⁺ there was no change, the concentration being about 140mM in both groups of beetles.
• 3.3. The marked drop in the extracellular concentration of Mg²⁺ might indicate that Mg²⁺ is involved in the regulation of the concentration of glycerol, which was reduced to zero during the warm acclimation.
• 4.4. The estimated equilibrium potentials of the respective ions might indicate that K⁺ is in electrochemical equilibrium across the cell membranes, whereas Na⁺ and to a lesser extent Mg²⁺ are actively transported out of the cells.
• 5.5. For Na⁺ there was a high positive equilibrium potential even in the cold acclimated beetles, indicating that Na⁺ has a high electrochemical potential difference across the cell membranes even at low temperatures. This is in agreement with the observation that hibernating insects are able to perform coorclinated walking immediately after heating to temperatures near zero.

     

Seasonal variation in the metabolic rates and Q10-values of the fingernail clam,Sphaerium striatinum lamarck

• 1.1. Metabolic rates were highest during periods of maximum reproduction.
• 2.2. The exponent of the metabolic rate-weight equation varied seasonally, rates of metabolism of small animals exhibited greater annual fluctuations than those of large animals.
• 3.3. Absolute and weight-specific Q₁₀s (determined at 5–10°C above field temperatures) for smaller clams were greatest in the winter; absolute values of Q₁₀ were highest for larger individuals in the summer.
• 4.4. Small clams had Q₁₀ < 1.0 in the summer; Q₁₀-values for larger clams were near 1.0 at this time.
• 5.5. 38.9% of the total energy assimilated by the population annually was allocated to metabolism, which is near the low end of the range of values reported for freshwater molluscs, suggesting that this species can partition a large amount of energy to growth and reproduction.

     

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.

     

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.

     

Water fluxes and urine production in blue crabs (Callinectes sapidus) as a function of environmental salinity

• 1.1. Water efflux and urine production rates were measured in blue crabs acclimated to several salinities.
• 2.2. In 100% seawater the mean rate of water efflux (31.3 ml/100g hr⁻¹) was significantly greater than that in 50% seawater (18.9 ml/100 g hr⁻¹.
• 3.3. Water efflux was directly related to body weight.
• 4.4. The mean urine production rate was significantly greater in crabs acclimated to 50% and 30% seawater (0.17 and 0.18 ml/100g hr⁻¹) than in animals conditioned to 100% seawater (0.09 ml/100 g hr⁻¹).
• 5.5. The difference between theoretical net water fluxes for crabs exposed to 100% seawater and 50% seawater was similar to the difference in urine output in the same salinities, demonstrating the importance of the antennal gland in volume regulation.