Contribution of aerobic and anaerobic scope to the total metabolic scope of the desert skink,Chalcides ocellatus (Forskal)

• 1.1. Measurements of aerobic scope (resting and active oxygen consumption rates) and anaerobic scope (resting and active production of lactate rates in the whole body homogenates) were carried out on the desert skink, Chalcides ocellatus at temperatures between 10 and 40°C.
• 2.2. The aerobic scope was maximal around the preferred body temperature with a low thermal temperature dependence above the preferred levels.
• 3.3. During initial stages of forced activity, C. ocellatus employed anaerobic metabolism as its major energy source.

     

The effects of acclimatization on body weight and oxygen consumption in Dipodomys panamintinus

• 1.1. Seasonal acclimatization effects on oxygen consumption, body temperature, and body weight were evaluated in three different experimental groups of Dipodomys panamintinus.
• 2.2. Body weights of wild field as well as captive animals housed in outdoor sand cages were maximum in winter and lowest in summer for both sexes.
• 3.3. Mean oxygen consumption was maximum in winter and lowest during spring in both sexes of the wild field and captive exposed groups.
• 4.4. Neither weight nor oxygen consumption of indoor control animals varied with the seasons.
• 5.5. No significant differences in body temperatures were observed during either the fall or winter seasons.

     

Respiratory mechanisms and metabolic adaptations of an intertidal crab,Chasmagnathus granulata (Dana, 1851)

• 1.1. The ventilatory mechanism, gill area, sites of oxygen uptake, oxygen consumption and activity of a crab from south Brazil, Chasmagnathus granulata, were investigated.
• 2.2. The oxygen uptake seems to be restricted to the gill lamellae.
• 3.3. The gill area varies with the wet body weight, being relatively higher in smaller animals. There is not a significative reduction of the gill area in relation to species of the infralittoral zone.
• 4.4. C. granulata presents a mechanism for recirculating the water of its branchial chamber when exposed to atmospheric air.
• 5.5. The oxygen consumption and activity are reduced when the animals are exposed to atmospheric air. The reduction in the oxygen consumption may be related to the poorly adapted respiratory system, while the decrease in activity may be a mechanism for saving energy during this hypoxic period.

     

Oxygen consumption and production by tropical ascidians symbiotic with Prochloron

• 1.1. Oxygen consumption and production rates were measured in two species of colonial ascidians that contained the algal symbiont, Prochloron.
• 2.2. Despite differences in size and habitats, the colonies showed similar rates of oxygen consumption and production.
• 3.3. Oxygen production by the colonies was light dependent.
• 4.4. Based on the data presented, the symbiosis is similar to other algal-invertebrate symbioses in producing more oxygen than is consumed when illuminated.

     

Variations of respiratory rate of Tisbe holothuriae humes (copepoda,harpacticoida) in relation to temperature,salinity and food type

• 1.1. The influence of temperature (14,19, 24°C), salinity (26,32, 38,44%.) and food type (artificial diets: Fryfood, Mytilus, Soya, Yeast, Spirulina) on the respiratory rate of Tisbe holothuriae has been studied.
• 2.2. Oxygen consumption decreased with decreasing temperature, but with a greater rate at supra- or subnormal salinities.
• 3.3. Multiple-regression analysis showed the quadratic effect of temperature and the linear effect of salinity to be the more important factors affecting respiration.
• 4.4. The food type also seems to exert an important effect on oxygen consumption.
• 5.5. A significant lowering of respiration was observed for all food tested when the animals were starved.

     

Variations in response to environmental hypoxia of different colour forms of the shore crab,Carcinus maenas

• 1.1. The oxygen consumption of red and green Carcinus in normoxic and hypoxic sea water was determined, using an oxygen electrode in a sealed respirometer.
• 2.2. The red crabs had significantly higher “excited” oxygen uptake rates and a lower ability to compensate for hypoxia than the green crabs.
• 3.3. Red Carcinus display an emersion response to declining oxygen at lower oxygen tensions than the green crabs.
• 4.4. Mortality of red crabs exposed to prolonged anoxia was much greater.
• 5.5. The relationship of these findings to the zonation of the two colour forms on the shore is discussed.

     

Oxygen debt in reptiles: Relationship between the time required for repayment and metabolic rate

• 1.1. The increase in O₂ consumption in a 5 g lizard (Anolis carolinensis) after feeding and after maximal work was compared with that in a kilogram alligator (Alligator mississippiensis) treated similarly.
• 2.2. The amount of extra O₂ consumed/kg was the same in both. At the peak, there was a 2.6 fold increase in both animals following exhaustive work. Oxygen usage was elevated for 2 hr in the lizard and for 12 hr in the alligator, in inverse proportion to their respective metabolic rates.
• 3.3. Although the extra oxygen consumed was the same. feeding increased metabolic rate at the maximum by 300% in the alligator and by only 40% in the lizard.

     

Metabolic energy of intact honey bee colonies

• 1.1. In late winter, oxygen consumption of honey bee (Apis mellifera L.) clusters showed marked 24-hr periodicity, even when held under constant temperature conditions.
• 2.2. Minimal rates of metabolism (as low as 3.4 w kg ⁻¹) were usually reached at night (ca. 0500 hr), and maximum rates (as high as 33.5 w kg⁻¹) in midday (ca. 1400 hr).
• 3.3. Colonies with brood showed less excursion in daily metabolic rate, by maintaining higher night-time levels.
• 4.4. There is a pronounced decrease in metabolic rate for the intact cluster of 9480–23,394 bees from the rates reported for individuals or small groups of bees.

     

Individual and sibling-group variation in metabolism of lizards: The aerobic capacity model for the origin of endothermy

• 1.1. We measured standard, resting and exercise metabolism of 28 Chaicides ocellatus (Scincidae). Individual lizards consistently showed statistically significant differences in mass-independent rates of standard and exercise metabolism during three replicates of the experiments at weekly intervals.
• 2.2. Metabolic differences were also detected among groups of siblings.
• 3.3. Mass-independent resting metabolic rates were closely correlated with standard rates, but there was no correlation of metabolic rates during forced activity with either standard or resting rates.
• 4.4. These data suggest a heritable component of metabolism for lizards, but they do not support the “aerobic capacity model” of the origin of endothermy, which proposes that initial selection for high resting metabolic rates operated via selection for high rates of aerobic metabolism during exercise.

     

Effects of salinity and temperature on oxygen consumption in a freshwater population of Palaemonetes antennarius (Crustacea,decapoda)

• 1.1. After step-like increases in salinity the shrimps exhibit the smallest increase in oxygen consumption in the lower salinity range. At higher salinities the shrimps show longer recovery times and greater increases in the metabolic rate after salinity shock.
• 2.2. In steady-state experiments, the shrimps display the lowest oxygen consumption rates near the isosmotic point. The lowest metabolic rates occur at salinities of 3‰ and 10‰ At salinities of 20‰ and above the rate of metabolism increases by 20–30%.
• 3.3. The calculated osmoregulatory work for animals in fresh water amounts to only 2.7% of routine metabolism and drops to 1.1% for shrimps in 3‰ and 0.7% in 5‰ salinity.
• 4.4. Locomotory activity in the form of position change was not responsible for the increased oxygen consumption of the animals after salinity shocks. A “tentative swimming activity” by fast and frequent beating of the pleopods without position change may be an important factor in the increase of metabolic rates.
• 5.5. In its temperature response, the brackish water population has a higher metabolic rate than the freshwater one. Between 5 and 35°C Q ₁₀-values range from 4.01 to 1.37.

     

Laboratory studies on the oxygen consumption of the marine teleost,Lichia amia (Linnaeus, 1758)

• 1.1. The oxygen consumption of the marine teleost, Lichia amia was investigated under controlled laboratory conditions.
• 2.2. The routine oxygen consumption showed a strong circadian rhythm with the fish being mainly active during the light period.
• 3.3. The specific mass exponent (dimension: μg O₂/g/hr) is temperature independent and ranges from 0.27–0.29.
• 4.4. Starving the fish results in a mean decrease in active, routine and standard oxygen consumption of 21%, 24% and 20%, respectively.
• 5.5. Feecling led to an increase in the oxygen consumption of the teleosts, with the mean metabolic rate over the 24 hr that followed, being 58% and 50% higher for fish that had been starved for 162hr and 40 hr, respectively.
• 6.6. Apparent SDA showed some variation and ranged from 6.0 to 35.5%.
• 7.7. The results obtained are generally in agreement with those recorded for other teleosts.

     

Measurements of oxygen consumption in Mytilus edulis during exposure to,and recovery from,high sublethal concentrations of formaldehyde,benzene and phenol

• 1.1. The rate of oxygen consumption has been monitored continuously in M. edulis during acute exposure to high sublethal concentrations of formaldehyde, phenol and benzene and subsequent recovery periods of 96 hr.
• 2.2. The results are discussed in relation to changes in the electrochemical potential difference of sodium, the content of ATP and the tissue concentration of strombine.
• 3.3. After exposure to benzene and phenol, an increase in the rate of oxygen consumption that could not be explained by oxygen debt from the exposure period was observed.
• 4.4. Depression of the rate of oxygen consumption after exposure to formaldehyde may be explained by a reduced ability to extract oxygen from the water.
• 5.5. The pattern of oxygen consumption and behavioural responses, as well as the combined changes in the biochemical markers, were distinctly different in the three cases.

     

Metabolic rates of Calathus melanocephalus (L.) (coleoptera,carabidae) from alpine and lowland habitats (jeløy and finse,norway and drenthe,the netherlands)

• 1.1. Metabolic rates (ml O₂/mg/hr) of three geographically separated populations of the carabid beetle Calathus melanocephalus L. (Finse and Je 10y, Norway and Drenthe, The Netherlands) were measured and compared by ANCOVA.
• 2.2. No significant relationship (P > 0.05) between metabolic rates and body weight or sex of the animals were found.
• 3.3. Individuals mostly acclimated to low temperatures by increased metabolic rates and in the opposite direction to higher temperatures. Individuals collected in early summer also showed higher metabolic rates than those caught later in the autumn.
• 4.4. Contradicting the theory of metabolic cold adaptation, beetles from The Netherlands had the highest metabolic rates, beetles from Finse intermediate rates and beetles from Jeløy the lowest rates.
• 5.5. No significant relation were found between geographical origin of the beetles and their respective chill-coma temperature.

     

The effects of temperature and moisture on survival capacity,cuticular permeability,hemolymph osmoregulation and metabolism in the scorpion,Centruroides hentzi (banks) (scorpiones,buthidae)

• 1.1. The temperature and water relations of Centruroides hentzi females were investigated. At 12 and 72% relative humidity (RH), the lower and upper Lt₅₀ were -4.5 and 43.7°C, and -4.7 and 45.1°C, respectively. When exposed to high temperature stress, survivorship was significantly greater under mesic conditions.
• 2.2. Cuticular water loss was higher under xeric conditions (12% RH), ranging from 0.061 mg/cm²/hr at 30°C to 0.211 at 41°C.
• 3.3. Exposure to dry air (0–5% RH) resulted in a significant increase in hemolymph osmolality: from 441 to 688 mOsm over a 5 day period.
• 4.4. Mean oxygen consumption rates increased from 161.7 mm³/g/hr at 34°C to 541.6 at 44°C. ATPase activity was significantly higher in animals acclimated and tested at 35°C.

     

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.

     

Agaricus bisporus tyrosinase—II. Characterization of hydroxylase and dehydrogenase activities

• 1.1. Preparative Isoelectric focusing (PIEF) was used to isolate hydroxylasic and dehydrogenasic activities, at different pI.
• 2.2. The fraction at pI 4.7 and 4.9 displays a pure dehydrogenase activity (substrate l-DOPA).
• 3.3. This fraction did not react with tyrosine, either in the spot-test or in absorption spectra (200–620 nm), and did not exhibit any oxygen consumption.
• 4.4. The fraction at pI 4.1 and 4.3 reacted with both l-DOPA and tyrosine as substrate, showing dehydrogenase and hydroxylase activity.
• 5.5. The latter activity was confirmed by the oxygen consumption test, showing that molecular oxygen is used to ortho-hydroxylate tyrosine.

     

Respiration and energetics in west indian gorgonacea (Anthozoa,octocorallia)

• 1.1. The rates of oxygen consumption of five species of Gorgonacea were determined and their daily energy requirements for metabolism were estimated.
• 2.2. Oxygen consumption rates varied between 0.15 and 0.76 mg O₂ g organic matter⁻¹ hr⁻¹.
• 3.3. Daily energy requirements varied between 13 and 66 cal g organic matter⁻¹ d⁻¹.
• 4.4. Energy costs for maintenance were somewhat lower than in other reef-dwelling Anthozoa.

     

Cardiac responses of larval and adult tiger salamanders to submergence and emergence

• 1.1. The ECG of aquatic Amhystoma tigrinum from the Colorado Rocky Mountains was recorded while the animals submerged and emerged in water. Older larvae and metamorphosed adults were compared.
• 2.2. Free-swimming animals of both types showed slight emergence tachycardia when taking a “gulp” of air.
• 3.3. Preventing access to air for 30 min or more resulted in a slight bradycardia in larvae. Some adults responded with increased, others with decreased, heart rate depending on their level of excitement.
• 4.4. Restraining the animals before forced submergence caused a greater bradycardia than when unrestrained.
• 5.5. Low dissolved oxygen accentuated the cardiac responses of larvae to submergence but not in adults.
• 6.6. Atropine only partially blocked the diving responses of both forms.
• 7.7. The degree of submergence bradycardia seems to be a function of the ability to extract oxygen from water. It probably is not an adaptation to diving in these forms. Instead the submerged heart rate in these predominantly aquatic salamanders may be the “normal” rate with emergence tachycardias for breaths of air.

     

An experimental analysis of the metabolic rate and food utilization of northern pike

• 1.1. The metabolism of northern pike (Esox lucius) was determined by oxygen consumption and ration experiments to obtain data for an energy budget analysis.
• 2.2. Metabolic measures of oxygen consumption were most reliable, and were described by the equations: R_met = 27.5 Wt^0.82 at 14°C and R_met = 1.6 Wt^0.97at 2°C.
• 3.3. In addition, conversion efficiency (K₂ = 0.319 ± 0.064) and assimilation efficiency (0.872 ± 0.060) were determined.
• 4.4. Proximate composition of fish under various feeding regimes indicated that energy gain or depletion from the body was due to changes in amount of whole body tissue or body protein, rather than specific utilization or storage of lipid.

     

Metabolic responses of the mussels Perna viridis and Perna indica to declining oxygen tension at different salinities

• 1.1. Oxygen uptake and ammonia loss were monitored during responses to reductions of both salinity and oxygen tension (PO₂) in the marine mussels Perna viridis and Perna indica from southern India.
• 2.2. The proportional contribution of protein to total catabolic substrates under natural environmental conditions was as much as 96% in P. viridis, relative to only 19% in P. indica.
• 3.3. Normoxic oxygen consumption remained statistically unchanged in P. viridis conditioned to salinities between 32 and 15‰, with no obvious signs of distress. Although equally unaffected at salinities between 32 and 20‰, P. indica showed significantly reduced oxygen uptake following transfer from 32 to 15‰, and had died within the next 7 days.
• 4.4. At salinities greater than 20‰, P. viridis was better able than P. indica to regulate oxygen consumption independent of PO₂.
• 5.5. P. indica showed a compensatory increase in oxyregulatory capacity at 15‰. This exceeded unstressed abilities, helping to maintain albeit reduced oxygen uptake throughout wider ranges of PO₂.
• 6.6. Different responses recorded in each of these tropical and often intertidal species were in accordance with their natural distributions. Nevertheless, the oxyregulatory capacity in both species was higher than in bivalves from temperate and/or subtidally restricted habitats.