Patterns of fuel utilization by the thoracic muscles of adult worker ants. The use of lipid by a hymenopteran

• 1.1. Patterns of fuel utilization in the thoracic muscles of three species of ants have been established.
• 2.2. The thoracic muscles of Formica ulkei exhibit a typical Hymenopteran metabolic organization, relying exclusively upon carbohydrate oxidation for the provision of metabolic energy. This species feeds upon honeydew.
• 3.3. Pogonomyrmex californicus, a granivorous ant, exhibits a metabolic organization unprecedented for a Hymenopteran species. Its thoracic energy metabolism is based upon lipid oxidation.
• 4.4. Atta colombica, a fungus feeder, can metabolize both carbohydrate and fat, a versatility which is not typical of Hymenoptera.
• 5.5. It is concluded that patterns of fuel utilization in insects are not determined by phylogenetic inertia, but are selected to accommodate the activity patterns, feeding ecology and dietary regime of the species.

     

Plasma lipoprotein profiles and arylesterase activities in two inbred strains of rabbits with high or low response of plasma cholesterol to dietary cholesterol

• 1.1. Cholesterol feeding for 4 weeks of female and male rabbits of two inbred strains increased plasma cholesterol concentrations by about 11 and 48 mmole/I in the hypo- and hyperresponsive strain, respectively.
• 2.2. On the low-cholesterol pre-experimental diet, the hyporesponsive animals had significantly higher plasma HDL (high density protein) cholesterol levels than hyperresponders.
• 3.3. In both strains, cholesterol feeding caused elevations of cholesterol in all lipoprotein classes, the difference between the hypo- and hyperresponsive strains in essence only being observed in the VLDL (very low density lipoprotein) fraction.
• 4.4. Basal plasma total arylesterase activity was significantly higher in the hypo- than in the hyperresponsive rabbits.
• 5.5. Dietary cholesterol caused an increase in plasma esterase activity in both strains.
• 6.6. We suggest that in rabbits a low plasma arylesterase activity and a low concentration of HDL cholesterol are associated with an increased sensitivity to dietary cholesterol.

     

The effect of pyridoxine deficiency on aminotransferase activity in liver and white muscle of rainbow trout (Salmo gairdneri Richardson)

• 1.1. Aspartate aminotransferase activity in the white muscle of rainbow trout dropped significantly after the animals had received a pyridoxine-deficient diet for 7 days.
• 2.2. Alanine aminotransferase activity in the white muscle of rainbow trout dropped significantly after the animals had been fed on a pyridoxine-deficient diet for 21 days.
• 3.3. Alanine and aspartate aminotransferase activity in the liver of rainbow trout did not drop significantly until the animals had received a pyridoxine-deficient diet for 28 days.
• 4.4. After rainbow trout have received a pyridoxine-deficient diet for 35 days, feeding with complete diet for 7 days is sufficient to restore the aminotransferase activities to the levels observed in control animals.

     

Transport of cholesterol in the hemolymph of the mollusc Diplodon delodontus

• 1.1. The dietary and inter-organ cholesterol transport in the hemolymph of the bivalve mollusc Diplodon delodontus, was studied. Plasma and hemocytes were obtained after feeding labeled cholesterol to animals or injecting it into the posterior adductor muscle.
• 2.2. In both cases, cholesterol was incorporated either into plasma or hematic cells.
• 3.3. Two plasmatic fractions differing in their hydrated densities were recognized as cholesterol carriers and were isolated. They have characteristics of high density (HDL) and very high density (VHDL) lipoproteins, respectively.
• 4.4. The major lipids in the different classes of lipoproteins were free sterols in HDL and phospholipids in VHDL.
• 5.5. Neither low nor very low density lipoprotein transporting cholesterol was detected.

     

Evaluation of the effects of injected eyestalk extract on rhythmic locomotor activity in Carcinus

• 1.1. The effects of injection of purified eyestalk extract on the locomotor activity of rhythmic Carcinus have been evaluated in relation to the equivocal responses elicited in early experiments following injection of crude eyestalk extract.
• 2.2. In most cases, locomotor activity was depressed by the effect of an eyestalk hormone which also acts as a depressor of neural activity.
• 3.3. Anomalous hyperactivity observed when injecting some crude extracts is thought to be induced by an electrolytic imbalance in the haemolymph fluid, due to the exaggerated K⁺ level of the crude eyestalk extract.

     

The effects of chronic metabolic acidosis on patterns of protein synthesis in rat renal cortex

• 1.1. In the rat chronic metabolic acidosis increases the net synthesis of 17 renal cortex proteins by amounts ranging from 1.5 to 4.5-fold.
• 2.2. These proteins have molecular weights between 13,000 and 42,000 and isoelectric points between approximately 5.5 and 7.0.
• 3.3. No new proteins not also present in normal animals are detected in renal cortex samples from acidotic animals.
• 4.4. Three proteins undergo substantial reductions in their net synthetic rates in chronic metabolic acidosis.
• 5.5. On the basis of their physical properties and similar alterations in net synthetic rate in acidosis some of these proteins appear to be closely related and may be coordinately expressed in the rat kidney.

     

In vivo photo-affinity labelling of glutathione receptors mediating the tentacle ball formation,a behavioral response associated with the feeding of Hydra

• 1.1. The tentacle ball formation, a response associated with the feeding of Hydra japonica, with S-(p-azidophenacyl)-glutathione (GSPAP) was reduced upon illumination.
• 2.2. GSPAP did not cause the depression without illumination nor did illumination without GSPAP.
• 3.3. The concentration dependence of the response of the photolabelled animals suggested high and low affinity glutathione receptors. The low affinity receptor may be efficiently tagged with GSPAP upon photolysis.

     

Correlation of acid phosphatase but not alkaline phosphatase activity with myelination in the developing mouse brain

• 1.1. Neonatal mice received subcutaneous injections of buffer, thiourea (TU) or propylthiouracil (PTU).
• 2.2. The PTU-treated mice were sacrificed on postnatal day 14 (P14) and the TU-treated mice on P28.
• 3.3. Brain weights of the TU- and PTU-treated mice were not significantly different from the controls.
• 4.4. Acid but not alkaline phosphatase activity in the braistem decreased after TU and PTU treatment.
• 5.5. Myelination as indicated by intensity of luxol fast blue staining was weaker in drug-treated animals.
• 6.6. The level of myelin marker enzyme, 2′,3′-cyclic nucleotide 3′-phosphohydrolase, was lower in the brainstem of PTU-treated animals.
• 7.7. The results suggest a correlation between acid phosphatase but not alkaline phosphatase activity with myelination in the developing mouse brain.

     

Melatonin: A coupling device between oscillators in the circadian system of the ruin lizard Podarcis sicula

• 1.1. Chronic administration of melatonin (in silastic capsules) lengthened the free-running period of the locomotor rhythm and shortened the circadian activity time in Podarcis sicula held in constant temperature and darkness.
• 2.2. Lizards displaying a bimodal pattern of activity invariably became unimodal after melatonin administration.
• 3.3. The results support the hypothesis that melatonin acts as a coupling device between circadian oscillators driving the locomotor rhythm in Podarcis sicula.

     

Analysis of postembryonic development of locomotor activity rhythm by corpora allata implantation in the cricket gryllus bimaculatus

• 1.1. Male crickets Gryllus bimaculatus show a drastic change in circadian rhythm from nymphal diurnality to adult nocturnality, in association with an increase in activity level several days after the imaginai moult.
• 2.2. The corpora allata implantation into male 7th or 8th instar nymphs produced supernumerary instar nymphs in about 30% of the implanted animals, but did not affected the normal development in the remaining animals.
• 3.3. The majority of the supernumerary instar nymphs were diurnal and sexually inactive, although their internal reproductive organs appeared to be fully mature.
• 4.4. The supernumerary instar nymphs became nocturnal with an increase in activity level several days after the imaginai (9th) moult.
• 5.5. The roles of the nervous system in the regulation of the rhythm reversal are discussed.

     

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.

     

Temperature acclimation in amphibians: Changes in lactate dehydrogenase activities and isoenzyme patterns in several tissues from adult Discoglossus pictus pictus (Otth.)

• 1.1. The effect of cold (8 ± 2°C) acclimation on the lactate dehydrogenase activities and isoenzyme patterns from sartorius muscle, liver, heart and brain of adult Discoglossus pictus pictus (Otth.) was studied.
• 2.2. Two groups of animals were studied: one set of animals was trapped in October and another set in December. In both cases some of the animals were sacrificed upon collection and some others subjected to 5 months of acclimation at 8 ± 2°C before being sacrificed for analysis.
• 3.3. A general trend towards a decrease in LDH specific activity was observed during cold acclimation. The magnitude of change, but not the direction, depends on both the tissue examined and the season at which the experiment was initiated.
• 4.4. A complex LDH isoenzyme reorganization was also found in liver, heart and brain. In liver from Experiment 1 and in heart from both experiments, a relative maintenance in M-type LDH activity during cold acclimation was observed. However, in brain there was a relative maintenance of LDH₃ activity in both experiments.
• 5.5. The low behavioral activity (and its metabolic consequences) and the existence of an intrinsic annual rhythm in D. pictus metabolism are suggested as responsible for the observed enzymatic changes.

     

Cross-correlation analysis of cerebrobuccal connective activity during Aplysia feeding behaviour

• 1.1. Two “en passant” electrodes were implanted around the cerebrobuecal connective (CBC) of Aplysia and used to record the activity, in the unrestrained animal, under three behavioural conditions; (a) absence of feeding behaviour, (b) appetitive feeding behaviour and (c) consummatory feeding behaviour.
• 2.2. The two simultaneous recordings were subjected to cross-correlation analysis, to subdivide spikes on the basis of their direction and speed of propagation.
• 3.3. There was virtually no CBC activity in the absence of food and feeding behaviour.
• 4.4. During appetitive feeding the metacerebral giant cell (MCC) was active and traffic was heaviest in the cerebral-to-buccal direction.
• 5.5. During consummatory feeding, traffic was also sustained in the buccal-to-cerebral direction; there was a reduction in the activity of the MCC, and a peak in the activity travelling to the cerebral ganglia, in the region of higher conduction velocity, was especially pronounced.
• 6.6. Further analysis showed this peak to have its largest amplitude during the actual ingestion of food and to be the result of the firing of several different units.
• 7.7. CBC traffic in both directions was also activated in one case of “spontaneous” biting.

     

Aerobic metabolism in snapping turtles,Chelydra serpentina,after thermal acclimation

• 1.1. Oxygen consumption of resting and active snapping turtles at 10, 20 and 30°C was measured following acclimation to 10 and 25°C.
• 2.2. Cold acclimation results in depressed resting and active rates of oxygen consumption and in a decreased aerobic metabolic scope for activity; these changes facilitate hibernation.
• 3.3. Warm-acclimated animals have a high aerobic capacity which supports aquatic and terrestrial activity.

     

Serum lipids,thyroxine and catecholamine levels in the reindeer with reference to the annual climatic cycle

• 1.1. Blood glucose and lactate, serum total lipid and triglyceride, thyroxine (T₄), epinephrine and norepinephrine concentrations and serum dopamine-β-hydroxylase activity were studied in 76 reindeer hinds and 127 calves with reference to the seasons.
• 2.2. Blood glucose level tended to be lowest in Autumn, and blood lactate highest in Summer.
• 3.3. Serum total lipids were smallest in Spring (2.8 g/l) and greatest in Autumn (5.3 g/l). Triglycerides were smallest in Winter (0.18 mmol/l) and highest in Autumn (0.32 mmol/l). In calves the total lipids increased during the neonatal period.
• 4.4. Serum epinephrine correlated with the weight, age, blood glucose and total lipids of the animals. In adult animals the lowest serum epinephrine level was found in Spring and the highest in Autumn (55 vs 190 ng/ml).
• 5.5. Serum norepinephrine concentration and dopamine-β-hydroxylase activity were highest in Spring and decreased towards Autumn. Parturition affected these parameters significantly.
• 6.6. The preponderance of high levels of some blood constituents in Autumn may be attributable to the replenishment of energy supplies for Winter time and also to the rutting season.
• 7.7. T₄ was smallest in Spring and highest in Summer. It was slightly greater in Winter than in Autumn. This suggests that the metabolic rate is tower in Winter than in Summer. Thus, the adaptation of the reindeer to a cold climate mainly utilizes insulation.

     

Turnover of the glycerol moiety of different lipid classes during development of Ceratitis capitata

• 1.1. Labelling of triacylglycerols, diacylglycerols, phosphatidylelthanolamine, phosphatidylcholine and their lysoderivatives was followed during the development of Ceratitis capitata after feeding larvae with [³H]glycerol. Both, specific activity and dpm/individual were plotted versus the time of development.
• 2.2. Decay curve for diacylglycerols had two exponential components accounting for two metabolic pools of this lipid class. Decay curves for phosphoglycerides and triacylglycerols exhibited a monophasic behaviour.
• 3.3. Triacylglycerols had large values of the turnover time parameters consistent with their reserve nature; phosphoglycerides exhibited a turnover time lower than that of triacylglycerols and similar to that of diacylglycerols in agreement with their metabolic relationships.
• 4.4. Half-life values of lysoderivatives were shorter than that of diacylglycerols suggesting a rapid deacylation-acylation mechanism for the phosphoglycerides.

     

Facultative aestivation in a tropical freshwater turtle Chelodina rugosa

• 1.1. Chelodina rugosa dug from aestivation sites at the end of the dry season were immediately alert and well coordinated.
• 2.2. Compared with non-aestivating animals, aestivating turtles had 20% higher plasma osmotic pressure and 7% higher sodium. Coupled with a small, but significant weight gain upon return to the water, this suggested the occurrence of minor dehydration in aestivating animals.
• 3.3. Plasma lactate levels of aestivating animals were low, averaging 1.99 mmol/l, consistent with aerobic rather than anaerobic metabolism having sustained their long period under ground.
• 4.4. No evidence was seen of dramatic physiological specialization. Aestivation in this species is interpreted as a primarily behavioural adaptation, made possible by typically reptilian abilities to tolerate a wide range in plasma electrolytes and to survive long periods without feeding.

     

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.

     

Comparative study on the fatty acid and lipid composition of four marine fish larvae

• 1.1. Fatty acid and lipid class composition were determined in larvae of four marine species: Atlantic halibut (Hippoglossus hippoglossus L.), plaice (Pleuronectes platessa), cod (Gadus morhua) and turbot (Scophthalmus maximus) at hatching and prior to first feeding.
• 2.2. Total fatty acid content decreased in the four species with up to 50% reduction in one of the halibut groups. Docosahexanaoic acid (22:6 n-3) was especially utilized.
• 3.3. Low lipid utilization was found in turbot in relation to the other three species.
• 4.4. Water environmental temperature may explain some of the differences in the fatty acid utilization and the source of metabolic energy between cold water species (halibut, cod, and plaice) and temperate species (turbot), in the period from hatching to prior to first feeding.
• 5.5. Relative amounts of neutral lipids and phospholipids were similar in plaice, cod and halibut, approximately 25% and 75% of total lipids, respectively, and were approximately constant during the yolk-sac stage. Neutral lipids were dominant for turbot at hatching, accounting for 53–55% of the total lipids, while phospholipids predominated prior to first feeding, being 56–59%.
• 6.6. Phosphatidylcholine was catabolized in halibut, plaice and cod but not in turbot, while phosphatidylethanolamine tended to be synthesized in all four species.

     

Role of the visceral nerve in heart rate variations during different behavioral patterns in Megalobulimus sanctipauli (mollusca,gastropoda, pulmonata)

• 1.1. The role of the visceral nerve in mediating the changes in heart rate associated with different behavioral patterns was investigated in Megalobulimus sanctipauli.
• 2.2. The results of acute and chronic denervation experiments indicate that the visceral nerve has no excitatory or inhibitory tonic action on the heart of snails retracted into the shell, nor does it account for the increase in heart rate associated with the locomotion and feeding behaviors.
• 3.3. These changes in heart rate are, probably, indirect effects of increased activity such as an increase in venous return.
• 4.4. The visceral nerve is responsible for approximately 3/4 of the increase in heart rate associated with the first minute of extrusion.
• 5.5. The small increase in heart rate observed in denervated animals is probably caused by an increase in venous return generated by muscle activity that forces the head and food out of the shell.