Sea water drinking as a homeostatic response to dehydration in hatchling loggerhead turtles Caretta caretta

• 1.1. Hatching Caretta caretta may lose up to 12% of their initial hatched weight from water loss during emergence from the nest.
• 2.2. After subsequent osmotic and excretory water loss in sea water, hatchlings will drink sea water (166 μl 100 g⁻¹ hr⁻¹) and return to their initial weight within 10–15 days, without feeding.
• 3.3. There were no significant changes in plasma osmolarity or sodium levels over this period.
• 4.4. This osmoregulatory strategy is in marked contrast to that seen in the estuarine crocodile, Crocodylus porosus.

     

Adaptations of Crocodylus acutus and Alligator for life in saline water

• 1.1. American crocodiles (C. acutus) weighing less than 200 g are unable to grow when kept in 35 ppt sea water in the laboratory. Yet paradoxically there are some highly saline areas in south Florida where rapid growth occurs. It is possible that these conflicting observations can be reconciled by behavioral osmoregulation of young crocodiles.
• 2.2. Hatching occurs during the rainy season and small crocodiles may drink from the brackish “lens” available during and after rainfall.
• 3.3. Using a weekly regime of alternating exposure to 35 ppt (6 days) and 4 ppt (12–24 hr), it has been demonstrated that growth of small crocodiles occurs. Feeding takes place primarily when brackish water is available. Salinities as high as 18 ppt were drunk when crocodiles were dehydrated by 15–20% of initial mass.
• 4.4. C. acutus and Alligator have a rather low rate of water efflux in sea water (0.2ml/100g-hr).
• 5.5. Sodium influx in sea water of C. acutus is low, but higher than efflux. Thus there is no evidence yet for a significant role of the lingual salt glands in sodium excretion.
• 6.6. The major adaptations to saline water of hatchling C. acutus are a low intake of sodium, an ability to selectively drink water of lower salinities, and to grow very rapidly (within 3–4 months) to a size much more tolerant of immersion in 35 ppt sea water.

     

Adenosine triphosphate as a determinant of magnesium levels in cytoplasm

• 1.1. Levels of free magnesium ion in various tissues are reviewed.
• 2.2. Total magnesium and ATP levels in different tissues are correlated, due to the presence of MgATP.
• 3.3. Relationships between pH and temperature in poikilotherms are such as to keep constant the amount of magnesium bound by ATP.
• 4.4. ATP hydrolysis in vivo generally tends to release magnesium ions, but conditions in some muscle may be such as to minimize this release.

     

Adaptation of rainbow trout (Salmo gairdnerii) to sea water: Changes in calcitonin levels

• 1.1. The calcitonin content of the ultimobranchial body (UBB) and plasma levels of calcitonin, calcium and phosphate were measured in rainbow trout (Salmo gairdnerii) following their transfer from fresh to sea water.
• 2.2. The plasma calcium level remained unchanged throughout the experiment while the UBB calcitonin content, plasma calcitonin and plasma phosphate rose significantly during the hours immediately following transfer.
• 3.3. The levels of all three subsequently fall so that, 8–15 days later, a new equilibrium was established with lower than control (fresh water) levels of UBB calcitonin, plasma calcitonin and plasma phosphate.
• 4.4. It would appear, from these data, that calcitonin plays some part in the endocrine regulation of sea water transfer.

     

Biochemical studies in a eunicid (polychaete) of the littoral of São Paulo,Brazil

• 1.1. The sodium, potassium, chloride, calcium, magnesium, phosphorus, sulphur, copper, iron, total carbon dioxide, uric acid, creatinine, urea, glucose, erythrocruoin, nitrogen, total iodine, protein-bound iodine, total lipids, triglycerides, alkaline phosphatase activity, acid phosphatase activity and copper oxidase activity contents of the blood of the giant Polychaete, Eunice sp., were determined.
• 2.2. The osmolarity of the blood was 997 mOsm/1 and the pH was 6·49, a very low value. The bicarbonate concentration estimated by the Henderson-Hasselbach equation was 4·70 mM/1.
• 3.3. The values of the sea water, sediments, water contained in the tube, tube, cuticle, muscle and faeces are also given.
• 4.4. The chemical composition of the mucus was determined.

     

Factors regulating the functioning of the in vitro perfused aglomerular kidney of the anglerfish,Lophius piscatorius L.

• 1.1. Kidneys of Lophius were perfused from the renal portal vein with a Ringer's solution.
• 2.2. Mammalian and piscine neurohypophysial hormones (in doses of 20–500 ng/kg body wt) did not affect the rate of urine production or the urinary concentration of inorganic ions.
• 3.3. The rate of urine production and the urinary concentration of magnesium and sodium ions varied with the concentration of magnesium in the perfusate.
• 4.4. The rate of urine production was positively correlated with urine magnesium concentration (r = 0.83 ± 0.04) and negatively correlated with that of sodium (r = −0.40).
• 5.5. The urinary concentration of sodium ions varied inversely with that of magnesium ions (r = −0.89).
• 6.6. Ouabain treatment (0.1–0.8 mM/l) reduced the rate of urine production by over 60% and altered, to varying extents, the pattern of electrolyte excretion. A simple model for the mode of formation of urine by the aglomerular kidney, based on the present results and other observations is suggested.

     

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.

     

Na+/H+ exchange in the kidneys of eels (Anguilla anguilla) adapted to sea water or to freshwater environments: Studies with brush border membrane vesicles

• 1.1. In brush border membrane vesicles isolated from eel kidneys, adapted either to sea water or freshwater environments, a Na⁺/H⁺ antiporter is present.
• 2.2. Using a calibration plot it is possible to evaluate the amount of protons that this antiporter can accumulate inside the vesicular space.
• 3.3. The activity of the antiporter seems to be affected by the salinity of the water; it is higher in animals adapted to seawater.
• 4.4. This adaptation seems to occur by a J_max regulation of the antiporter.

     

Identification and estimation of dopamine released from the anterior byssus retractor muscle of Mytilus californianus in response to nerve stimulation

• 1.1. Small quantities of sea water were recyclically perfused over the surface of paired anterior byssus retractor muscles of Mytilus californianus.
• 2.2. Dopamine was identified in the perfusate by thin-layer chromatography.
• 3.3. Stimulation of the pedal ganglion caused the dopamine content of the perfusate to increase.
• 4.4. A significant increment of release of dopamine was detected at stimulation frequencies above 3 Hz and increased progressively with increase in stimulation frequency.
• 5.5. The possibility of a role for dopamine as a relaxing or inhibitory neurotransmitter in Mytilus is considered in relation to the present and related evidence and to the actions of 5-HT, the probable relaxing transmitter.

     

In situ perfusion study of sodium transport across the nephridia of a marine invertebrate Sabella pavonia S. (Polychaeta; Annelida)

• 1.1. A suitable perfusion rate (0.110μl/min) was calculated after measuring nephridial volume and urine transit time.
• 2.2. Neither inulin nor albumin were found suitable as water movement markers for nephridia.
• 3.3. There was no net sodium flux through the nephridial wall.
• 4.4. Measurements of net nsodium flux through the nephridia showed that, in normal sea water, Sabella could not transport large amounts of sodium against a concentration gradient. A unidirectional sodium flux of about 10nequiv/min per cm crossed the nephridia.

     

Echinochrome-A as a bactericidal substance in the coelomic fluid of Echinus esculentus (L.)

• 1.1. The concentrations of echinochrome-A in coelomic fluid from healthy specimens of the sea urchin Echinus esculentus (L.) ranged from 3 to 60 μg/ml, with a geometric mean of 14 μg/ml.
• 2.2. Echinochrome-A (50 μg/ml) dissolved in sea water, with the aid of mammalian proteins as dispersants, was bactericidal or bacteriostatic towards six out of seven strains of marine gram-negative and gram-positive bacteria.
• 3.3. Echinochrome-A is suggested as a major factor in the bactericidal activity of coelomic fluid from E. esculentus.

     

Kinetic studies of catechol-o-methyltransferase from the brain of the African catfish,Clarias gariepinus

• 1.1. Optimum in vitro conditions, and kinetics of the enzyme catechol-O-methyltransferase from the brain of the male African catfish were studied.
• 2.2. A saturated level for S-adenosylmethionine, as methyldonor, and magnesium as cofactor was reached at 5 μM and 10 mM, respectively.
• 3.3. The addition of ascorbic acid, as an antioxidant, and tranylcypromine, as a MAO inhibitor, was not necessary, during incubations with fore-brain homogenates.
• 4.4. Kinetic analysis of the methylation of catecholestrone, catecholestradiol and dopamine showed K_m values of 1.2, 0.6 and 0.5 μM, respectively.
• 5.5. The affinity of the catecholsubstrates for the enzyme catechol-O-methyltransferase is much higher in the brain of the African catfish than in tissues of mammals.

     

Studies on the nutrition of the supralittoral isopod Ligia pallasii using chemically defined artificial diets: Assessment of vitamin,carbohydrate, fatty acid,cholesterol and mineral requirements

• 1.1. An artificial diet, consisting of a dry aggregate of 59 chemical substances, was used to assess the requirements of the sea slater Ligia pallasii for vitamins, carbohydrates, fatty acids, cholesterol and minerals.
• 2.2. Good growth and survival of L. pallasii was obtained on the diet, comparable to that on seaweeds and to that shown by a field population.
• 3.3. No dietary requirements for vitamins, fatty acids or cholesterol were shown for periods of 40 weeks or more for L. pallasii.
• 4.4. Carbohydrates were shown to be required by L. pallasii in its diet, in the order: starch, lactose > maltose, glucose > sucrose, cellulose.
• 5.5. Dietary requirements for minerals were, in order: calcium, magnesium, phosphorus > copper, nickel, zinc > iron, manganese, sulphur > iodine, silicon.
• 6.6. The results are discussed in relation to the role of gut bacteria in supplying required nutrients to their isopod hosts and the enhancement of this process through coprophagic behaviour.

     

Evaporative water loss and uptake in juvenile and adult Salamandra salamandra (L.) (Amphibia: Urodela)

• 1.1. Both juveniles and adults of this rare salamander were studied.
• 2.2. The rate of evaporative water loss increased with temperature and at lower humidities.
• 3.3. At all four temperatures and three humidities studied, adults lost water at a lower rate than juveniles.
• 4.4. Aggregating juveniles reduced water loss especially at lower moisture.
• 5.5. The rate of water uptake was greater in juveniles than in adults.
• 6.6. Juveniles were capable of absorbing moisture from moist soil even at 40% saturated soil.

     

Fluxes of dissolved amino acids between sea water and Echinaster

• 1.1. Measurement of free amino acid (primary amine) influx and efflux into the starfish, Echinaster, were accomplished utilizing improved methods of sea water purification and analysis.
• 2.2. Specimens placed in amino acid depleted sea water (5 × 10⁻⁸ M) demonstrated net release as measured with the fluorescamine method. Similarly, specimens placed in the same water to which amino acid mixtures had been reintroduced to normal levels demonstrated net uptake.
• 3.3. A mathematical model indicated an equilibrium amino acid concentration (when influx equals efflux) of 5.26 × 10⁻⁷ M, or about one fourth the level of natural sea water.
• 4.4. Since at normal environmental levels (20.65 × 10⁻⁷ M) net flux is inward by a ratio of nearly 4-1, it is concluded that the previous suggestions of some workers that such would not be the case for marine invertebrates are no longer valid.
• 5.5. The net uptake of amino acid from environmental levels would account for 5.67% of the measured total respiration if all were being metabolized.
• 6.6. This figure appears to be in line with the previously developed hypothesis that the epidermis largely obtains its nutrition directly from the environment. However, the real benefit of the uptake mechanism may be to prevent loss of the body amino acid pools.

     

Interrelationship between metabolism of tritiated water, 22sodium and dry matter intake by beef cattle consuming wheat straw and poultry litter in free choice

• 1.1. Metabolism of tritiated water and ²²sodium was studied in six beef cows under Mediterranean summer conditions in order to find whether the turnover of these tracers can be used to evaluate pasture intake.
• 2.2. The diet of the cows included ad libitum access to two components which were given separately in different troughs: one was poultry litter and the other was wheat straw, to simulate the dry pasture.
• 3.3. Voluntary daily dry matter intake (111 g/kg^0.75) was unexpectedly high considering the low digestibility of the feed.
• 4.4. The assumptions of constant ratios of water intake to water turnover and of dry matter intake to water intake were confirmed. Consequently, dry matter intake was determined accurately from water turnover measurements.
• 5.5. Sodium intake was practically equal to sodium turnover and most of the sodium secreted in feces was of endogenous origin.
• 6.6. Pasture intake can be predicted from sodium turnover once the concentration in feed and water consumed is known.

     

The effect of ovine prolactin on sodium and water transport across the intestine of the fowl (Gallus domesticus)

• 1.1. The effects of ovine prolactin on sodium and water transport across the intestine of 9-day old cockerels were studied by an in vitro everted gut sac technique and by an in vivo balance technique.
• 2.2. Prolactin was found to reduce sodium and water transport across the jejunum and the rectum. AVP was ineffective.
• 3.3. Plasma sodium levels tended to decrease in prolactin treated birds.
• 4.4. It is suggested that the action of prolactin on intestinal salt and water transport is important in maintaining electrolyte homeostasis.

     

Effects of membrane-perturbing drugs and noradrenalin on cAMP accumulation and red cell water content in carp (Cyprinus carpio) red cells

• 1.1. Carp red cells were treated with drugs that affect the cell membranes. The water content of the cells and the accumulation of cAMP in the cells were measured in normoxia and in hypoxia using non-stimulated and adrenergically stimulated cells.
• 2.2. WGA, DIDS + CCCP and A23187 increased the water content of nonstimulated normoxic cells.
• 3.3. In hypoxia ouabain and DIDS + CCCP increased the water content but cytochalasin B, NPM, DIDS, CCCP and A23187 + CA²⁺ abolished the hypoxia-induced swelling.
• 4.4. Any membrane perturbation induced some cAMP formation, Sophora and Anquilla lectins being most potent.
• 5.5. Also in adrenergically stimulated cells, membrane perturbation generally increased cAMP formation.
• 6.6. However, cAMP accumulation diminished in cells treated with cytochalasin B, CCCP and DIDS + CCCP.
• 7.7. The adrenergic swelling of carp red cells was reduced in normoxia by DIDS. NPM and CCCP increased the adrenergic swelling in normoxia to hypoxic level.
• 8.8. In hypoxia WGA and Anquilla lectin decreased the swelling.

     

Short-term osmotic responses of cells and tissues of the sea anemone,Condylactis gigantea

• 1.1. Cells of tentacles and body wall of the sea anemone Condylactis gigantea behaved as simple osmometers during 5hr exposure to 50, 67, 83, 100 and 125% sea-water.
• 2.2. All intracellular water appeared to be osmotically active.
• 3.3. Cell sodium, chloride and total osmolyte content remained invariable, with taurine decreasing and potassium increasing as sea-water concentration was reduced.
• 4.4. Tissues, as a whole, exhibited a pseudoregulatory response to changes in salinity as the large and osmotically inert extracellular space buffered volume changes to a considerable extent.

     

Physiology of terrestrial isopods

• 1.1. This article reviews the physiology of oniscidean isopods, a group of terrestrial crustaceans known commonly as woodlice or sowbugs.
• 2.2. The oniscideans are represented by several hundred species in 34 families and occupy habitats ranging from sea beach to woodland, grassland and desert.
• 3.3. The widespread interest in woodlice stems, in part, from their evolutionary transition from marine to terrestrial habit directly over sea beaches. Representative stages of this evolutionary transition are extant within the oniscidean group.
• 4.4. Water and water relations have featured prominently in the accession to land by woodlice; consequently, these topics have been the focus of much historical and recent research work. The present review builds on a strong foundation of behavioural research on water relations and explores the evolutionary success of these unique crustaceans from a physiological point of view, emphasizing recently published work.
• 5.5. Topics include gas exchange and effects on VO₂, marsupial adaptations, water-vapour absorption, ammonia excretion, moulting and its neuroendocrine control, nutrition and osmotic regulation