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.

     

Skeleton weight-free oxygen consumption related to adaptations to environment and habits of six crustacean species

• 1.1. Oxygen consumption in six crustacean species from the continental shelf of the NW Gulf of Mexico was related to the ash free weight per dry weight (afdw) gram of the tissue excluding the exoskeleton, suggesting a close relationship to their life strategies.
• 2.2. Dry weight exoskeleton proportion varied among species, with highest values recorded in callapid brachyuran crab species (46.8–52.5%) against the values recorded in portunid crab (45.8–48%) and the shrimp species (26.7–35.7%).
• 3.3. Oxygen consumption was related to afdw in each species according to the expression y = ax^b, with b values ranging from 0.68 to 2.92.
• 4.4. Rates of oxygen consumption per afdw/dw were larger in shrimps than in portunids and callapids, and was related to the morphophysiology and lifestyle of six species described; the former as the morphological design of the exoskeleton versus the muscle content in the species and the latter as the activity rate in the environment.
• 5.5. The oxygen extraction efficiency, calculated from oxygen consumption, was higher in the eurytopic species Penaeus aztecus and Callinecies similis than in species restricted to the marine environment, hence considered as a response to environmental fluctuations.

     

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.

     

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.

     

Effects of temperature and acid stress on hatching,survival capacity,metabolism and postural reflexes in caenid mayflies (ephemeroptera)

• 1.1. Mortality was 100% at pH 3.5 over a temperature range of 10–30°C for embryos and nymphs of Caenis diminuta and C. hilaris.
• 2.2. Hatching success for both species was highest at pH values above 4.5.
• 3.3. Survival capacities were significantly higher at 20°C over a pH range of 4.0-7.2.
• 4.4. Oxygen consumption rates increase as a function of increasing temperature and reduced acidity.
• 5.5. Loss of the nymphal righting response was observed at pH 3.5. This response can be used as a behavioral assay for acid stress.

     

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.

     

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.

     

The effect of salinity and ion composition on oxygen consumption and nitrogen excretion of Macrobrachium rosenbergii (de man)

• 1.1. Oxygen consumption and nitrogen excretion rates of Macrobrachium rosenbergii were recorded in media of varying salinities and ion compositions (Mevo Hamma, Yahel, Elat—continental water; and 15 and 24%. seawater dilutions).
• 2.2. Oxygen consumption rates were not significantly different (P > 0.05) with the exclusion of Yahel having a metabolic rate of 0.258ml O₂/gfw/hr which was significantly different from the other experimental media at the P ≲- 0.05 level.
• 3.3. Nitrogen excretion rates were lowest in prawns adapted to Yahel water, 0.0188mg NH₄-N/gfw/hr and increased with salinity to 0.0494mg NH₄-N/gfw/hr in 24%.
• 4.4. The O: N ratios ranged from 12.24 to 22.65 indicating that in dilute media (Mevo Hamma and Yahel) relative to saline media (15%, Elat and 24%) more lipids and carbohydrates are utilized as an energy substrate while the latter group increased protein catabolism.

     

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.

     

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.

     

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.

     

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.

     

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.

     

Heat production of fish: A literature review

• 1.1. Results of investigations on direct calorimetry and simultaneous measurements of oxygen consumption and carbon dioxide and ammonia production of fish are summarized.
• 2.2. By means of indirect calorimetric formulae, the heat production and the protein, carbohydrate and fat oxidation are calculated from the oxygen consumption and carbon dioxide and ammonia production.
• 3.3. The lowest heat production values are obtained by long-term monitoring of groups of fish during darkness and under fasting conditions.
• 4.4. It is concluded that the heat production of standard metabolism at 20°C is 700J/hr/MW (MW = metabolic weight, kg^0.85).

     

The oxygen consumption rates of three gastrotrichs

• 1.1. The oxygen consumption rates for three sympatric species of marine gastrotrichs (anatomically similar, except that one contains hemoglobin) were measured with a Cartesian diver microrespirometer.
• 2.2. The rates for the two species without hemoglobin, Turbanella ocellata and Dolichodasys carolinensis, were 307.2 μl O₂ g⁻¹ hr⁻¹ and 108.0 μl O₂ g⁻¹ hr⁻¹, respectively, while the rate for the hemoglobin-containing species, Neodasys, was 208.9 μl O₂ g⁻¹ hr⁻¹.
• 3.3. The possession of hemoglobin by Neodasys (14% by volume) cannot be explained by an unusually high demand for oxygen.
• 4.4. Instead, the hemoglobin may be useful as an oxygen store providing continued aerobic metabolism in anoxic conditions, thus allowing Neodasys to exploit a different niche.

     

Specific dynamic action and feeding metabolism in common carp,Cyprinus carpio L.

• 1.1. Oxygen uptake attributable to Specific Dynamic Action (SDA) was measured in common carp, Cyprinus carpio L. (63.6–84.0 g) fed on 20, 35 and 50% dietary protein at 0.40 to 1.00% ration levels at 28°C.
• 2.2. After feeding both SDA magnitude and mean peak oxygen consumption increased directly with dietary protein and ration levels. SDA duration was not significantly related to dietary protein but significantly increased with ration levels.
• 3.3. SDA coefficients were 8.99, 13.51 and 15.94% with 20, 35 and 50% dietary protein showing a direction relationship to the protein content. The SDA coefficient did not change with ration size.
• 4.4. SDA models resulting from this work are of great interest for the aquaculturist, as post-feeding oxygen requirements in an intensive fish culture can be predicted where dietary protein and ration levels are known.

     

Oxygen consumption in the tortoise,Testudo hermanni G., subjected to sudden temperature changes in summer and autumn

• 1.1. A respirometer for long-term measurements of oxygen consumption in terrestrial vertebrates is described.
• 2.2. The tortoise, Testudo hermanni Gmelin, investigated in summer and autumn, presents a day-night rhythm of oxygen consumption at 28 and 18°C but not at 8°C.
• 3.3. The standard metabolic rate presents an important and constant thermal dependence in the range 8-18-28°C.

     

Respiratory function and nucleotide composition of erythrocytes from tropical elasmobranchs

• 1.1. Oxygen carrying capacity and parameters of erythrocyte-oxygen binding are similar for a range of elasmobranchs with markedly different swimming behaviour.
• 2.2. Erythrocyte nucleotide components in sharks include the allosteric hemoglobin modifiers GTP and ATP in similar ratios, and the total pool appears independent of locomotory activity. A rhinobatoid ray had no detectable erythrocyte trinucleotides, but had an appreciable pool of AMP together with IMP.
• 3.3. There was no evidence for either urea or NaCl modulation of hemoglobin function in erythrocytes from a carcharhinid shark.
• 4.4. These observations lead to the conclusion that parameters of the oxygen transport system in elasmobranchs are highly conserved.

     

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.

     

Oxygen binding characteristics of whole-blood and hemoglobin from the snake Thamnophis sirtalis

• 1.1. Oxygen binding capabilities of whole-blood and hemoglobin from the snake Thamnophis sirtalis were analyzed, at different temperatures and with various organic phosphate concentrations.
• 2.2. In whole-blood, the Hb-Hb co-operativity increases at high oxygen saturation, and at high temperatures (20 and 30°C) at low saturations as well. The co-operativity is slightly in excess of 4.
• 3.3. Half-saturation co-operatively in hemoglobin solutions increases significantly (0.2—0.4 units) on addition of ATP, but not when the temperature is raised.