Hemolymph osmoregulation in three species of beetles

• 1.1. Hemolymph osmoregulation was examined in Chrysochus auratus, Tetraopes tetrophthalmus and Tenebrio molitor. These beetles differed in their water loss rates and in the availability of free water in their habitats.
• 2.2. During dehydration at comparable rates, osmotic responses were similar in these species. Osmoregulation after rehydration was better in C. auratus.
• 3.3. Osmoregulation ability was not significantly affected by the beetle's rate of dehydration.

     

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.

     

Ventilatory rate in the butterfish (Pholis gunnellus) as a consequence of temperature and previous emersion

• 1.1. Observation of ventilation in immersed Pholis gunnellus showed a linear relationship between ventilatory rate and temperature between 8 and 20°C.
• 2.2. At 13°C and after 30 min emersion, ventilatory rate was initially lower than prior to emersion, providing evidence of adequate uptake of O₂ for standard metabolism during the emersion period.
• 3.3. This species has a laterally elongate body form with reduced scales and extensive mucus secretion.
• 4.4. During emersion, gaping behaviour probably exposes the gills and extensively vascularised oesophageal regions to air.
• 5.5. These are considered to be morphological and behavioural adaptations by P. gunnellus, to aerial respiration in the intertidal habitats occupied by this species.

     

Hyperosmotic properties of the fluids of the perivisceral coelom and water vascular system of starfish kept under stable conditions

• 1.1. Osmotic measurements were made on the perivisceral coelomic and water vascular fluids of 4 species of northwest Pacific starfish and their stable sea-water media.
• 2.2. Mean levels of both fluids were hyperosmotic in every species, often at statistically significant levels.
• 3.3. For all species combined, mean hyperosmolality (mosmol/kg ± SE) of perivisceral coelomic fluid was 1.49 ± 0.17, and water vascular fluid 6.07 ± 0.74.
• 4.4. The hyperosmotic nature of these fluids contributes to water balance, working in conjunction with madreporitic inflow and other factors.

     

Water relations and thermal sensitivity of several cockroach species (Dictyoptera: Blattidae and blaberidae)

• 1.1. Per cent total body water content (%TBW), cuticular permeability (CP), rate of water loss, critical thermal maxima (CTMax), and upper lethal limits (ULL) were determined for Pacific beetle, Diploptera punctata (Eschscholtz), Surinam, Pycnoscelus surinamensis (L.), and Turkestan, Blaita lateralis (Walker), cockroaches.
• 2.2. Initial body mass ranged from 153.16 to 464.96 mg, for D. punctata and P. surinamensis cockroaches, respectively. Mean %TBW was 57.8 for P. surinamensis and 67.7 for B. lateralis.
• 3.3. Mean cuticular permeability was not related to initial mass and ranged from 20.9 to 38.7 μg/cm²/hr/mmHg for D. punctata and P. surinamensis, respectively.
• 4.4. Cumulative mass loss and %TBW lost increased linearly with desiccation time.
• 5.5. CTMax ranged from 43.2°C for D. punctata to 44.3°C for P. surinamensis. There were significant, but small differences in CTMax among the three species.
• 6.6. ULL were 2.2 to approximately 4°C greater than CTMax. The greatest ULL was 48.1°C for B. lateralis and the lowest ULL was 45.0°C for D. punctata.

     

Osmoregulatory adjustments by three atherinids (Leptatherina presbyteroides; Craterocephalus mugiloides; Leptatherina wallacei) to a range of salinities

• 1.1. Patterns of osmoregulation were studied in three species of Swan river atherinids (Leptatherina presbyteroides, lower estuarine and marine; Craterocephalus mugiloides, mid estuarine; Leptatherina wallacei, upper estuarine) over a wide range of salinities.
• 2.2. The plasma Na⁺ concentration was elevated with an increase in salinity.
• 3.3. Haematocrit and body water content decreased with acclimation to higher salinity.
• 4.4. All three species of atherinids osmotically regulated over a salinity range greater than that which these fish are reported to occur in.

     

A test of the thermal coadaptation hypothesis with black rat snakes (Elaphe obsoleta) and northern water snakes (Nerodia sipedon)

• 1.The thermal coadaptation hypothesis predicts that (1) ectotherms experiencing a narrow range of body temperatures in the wild will evolve to perform well over a narrow range of body temperatures and that (2) the optimal temperature for performance will be equal to the preferred body temperature of the species.
• 2.We tested the predictions of the thermal coadaptation hypothesis with black rat snakes (Elaphe obsoleta) and northern water snakes (Nerodia sipedon) because black rat snakes experience lower and more variable body temperatures than northern water snakes at our study site.
• 3.We measured swimming speed, tongue-flicking speed, and striking speed in black rat snakes, and swimming speed and tongue-flicking speed in northern water snakes.
• 4.Adult water snakes generally had narrower performance breadths and higher optimum performance temperatures than adult black rat snakes.
• 5.Performance breadths were the same for swimming, tongue flicking, and striking within adult black rat snakes, but performance optima for these behaviours differed significantly. Performance breadths differed and performance optima were the same for swimming and tongue flicking within adult northern water snakes.
• 6.The relative swimming performance of neonates of the two species was similar in breadth to that of adults, but the thermal optimum for neonate black rat snakes was higher than that of adults.
• 7.Overall, our results provided support for the thermal coadaptation hypothesis.

     

Volatile fatty acid excretion during anaerobiosis in the lugworm Arenicola marina

• 1.1. Accumulation and excretion of propionate and acetate during experimental anaerobiosis were investigated in the lugworm Arenicola marina.
• 2.2. The rate of accumulation and the ratio propionate/acetate were found to be tissue-specific.
• 3.3. The excretion of the volatile fatty acids showed a characteristic time course.
• 4.4. The results of experiments analyzing the role of different organs indicate that the excretion of these metabolites proceeded via the undifferentiated surface of the body.
• 5.5. The rate of excretion depended on the concentration gradient between animal and the ambient water, the chain-length of the fatty acid and the pH of the water. Propionate excretion was inhibited by butyrate.

     

Anuran amphibia which are not acclimable to high salt,tolerate high plasma urea

• 1.1. The capacity of five anuran Amphibians (Bufo viridis B. regularis, Rana ridibunda, Hyla arborea and Pelobates syriacus) to acclimate to NaCl and urea solutions was investigated.
• 2.2. All species could be acclimated to relatively high concentrations of urea solutions, while only Bufo viridis and Hyla arborea could be acclimated to 500 mOsm/kg or higher NaCl solutions.
• 3.3. The plasma urea concentration in B. viridis and H. arborea was elevated to levels over 140 mmol/1.
• 4.4. The sum of plasma sodium and chloride concentrations did not increase over 400 mmol/l in any species.
• 5.5. Urine osmolality, which was normally low, increased, but never exceeded the plasma osmolality.
• 6.6. In the urea acclimation conditions, urine electrolytes diminished, similarly in all species in this study.
• 7.7. It is concluded that anuran Amphibians can tolerate high plasma urea concentrations, but only those species which can elevate it, either through retention or net synthesis, can be acclimated to high salt solutions.

     

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.

     

Correlation of water translocation,cuticle dehydration and post-ecdysial sclerotization by the american cockroach

• 1.1. Haemolymph volume decreases during the initial 16 hr post-ecdysial period, increases after water ingestion and subsequently drops until the inter-ecdysial level is reached.
• 2.2. Total body water follows a similar pattern, but the changes are not as pronounced.
• 3.3. Tissue water is inversely proportional to the total body water.
• 4.4. Soluble cuticle protein declines throughout the initial 16 hr period while both β-glucosidase and alkaline phosphatase activity is lost within 6 hr after ecdysis.
• 5.5. Dehydration of the cuticle also occurs during the immediate 6 hr post-ecdysial period.
• 6.6. These data suggest that the formation of the protein-insoluble matrix is linked with water loss.
• 7.7. Water removal may decrease the distance between molecules allowing specific reactions to take place.

     

A novel inhibitor of glycogen phosphorylase from crayfish hepatopancreas

• 1.1. A novel glycogen phosphorylase inhibitor was partially purified from crayfish hepatopancreas.
• 2.2. The inhibitor was found only in two species of crayfish examined, and not in lobster, fresh and salt water clams, mussels or cockroaches.
• 3.3. The inhibitor is a small protein (M_r = 23,000) which did not show proteolytic activity.
• 4.4. Preliminary kinetic analysis of the inhibitory mechanism indicated that it bound to both glycogen and the glycogen phosphorylase protein.
• 5.5. Inhibitor binding to glycogen resulted in a competitive inhibition pattern with respect to glycogen phosphorylase (inhibition constant of ca 10 μg/ml).
• 6.6. The inhibitor also bound glycogen phosphorylase directly with a binding coefficient of 100 μg/ml resulting in a partially non-competitive inhibition pattern with respect to phosphate.

     

Effects of water stress on hemolymph volume,osmotic potential and chemical composition in Megetra cancellata

• 1.1. Rates of water loss in Megetra cancellata were very high compared to those reported for other xeric arthropods.
• 2.2. Hemolymph weight in hydrated animals was 43.0% of the total body weight while it was 24.7% in desiccated animals that had lost 16.1% of their body weight as water.
• 3.3. Hemolymph osmotic potential increased from 417 to 447 mOsm/kg in desiccated beetles, but osmotic regulation was evident.
• 4.4. Total hemolymph protein mass and concentration decreased in desiccated beetles while amino acid concentrations remained constant (at about 70 mM).
• 5.5. Na⁺ and −PO₄ concentrations increased in desiccated beetles.
• 6.6. Cl⁻ and K⁺ concentrations in desiccated beetles were equal to those in undesiccated beetles.

     

Scale regeneration of tilapia (Oreochromis niloticus) under various ambient and dietary calcium concentrations

• 1.1. Scale regeneration was examined in Oreochromis niloticus under normal, dietary calcium-deficient, and both dietary and ambient water calcium-deficient conditions.
• 2.2. Calcium contents of regenerating scales were dependent on the calcium status of the fish, but areal growth of the scales was independent.
• 3.3. Transient hypocalcemia accompanied with a loss of calcium from original scales was observed in descaled fish in dietary calcium deficiency, and intact and descaled fish in both dietary and ambient water calcium deficiency.
• 4.4. The results suggested that calcium mobilized from internal sources was insufficient and both water and dietary calcium were necessary for normal calcification of the regenerating scales.

     

Physiological diving adaptations of the australian water skink Sphenomorphus quoyii

• 1.1. Both the small riparian skink Sphenomorphus quoyii and its completely terrestrial relative Ctenotus robustus respond to forced submergence with instantaneous bradycardia.
• 2.2. The strength of the bradycardia was affected by water temperature and fear. Dives into hot (30°C) water produced weak and erratic bradycardia compared to dives into cold (19.5°C) water. For S. quoyii the strongest bradycardia occurred when submergence took place in water at a lower temperature than the pre-dive body temperature.
• 3.3. Upon emergence both species of skink exhibited elevated heart rates and breathing rates while heating from 19.5 to 30°C, compared to heating at rest. The increased heart and breathing rates probably act to replenish depleted oxygen stores and remove any lactate. Increased heart and ventilation rates are not indicators of physiological thermoregulation in this case.
• 4.4. Both lizard species exhibited higher heart rates and ventilation frequencies during heating than cooling.
• 5.5. Compared to its terrestrial relative, S. quoyii does not appear to possess any major thermoregulatory, ventilatory or cardiovascular adaptations to diving. However, very small reptiles may be generally preadapted to use the water to avoid predators.

     

A note on eggshell porosity,nest humidity and the effects of DDE in the grey heron (Ardea cinerea)

• 1.1. Water vapour conductance (G_H2O) was determined for 25 grey heron Ardea cinerea eggs in the laboratory, and in nests during natural incubation at two Scottish colonies.
• 2.2. The mean G_H2O of eggs measured in the nest which successfully hatched was 9.0 mgH;O/mmHg/day and the mean water vapour pressure gradient between egg and nest (ΔP_H2O), measured using “calibrated” duck eggs, averaged at 31 mmHg (4.13 kPa).
• 3.3. Based on eggshell porosity results, from the eggs which hatched, such a gradient would result in a loss of water from the eggs during incubation equivalent to 11% of their fresh weight.
• 4.4. Shell thickness, the number of pores/cm² of eggshell and DDE content were also determined for the 25 eggs measured in the laboratory.
• 5.5. Eggs containing high levels of DDE had thinner shells, more pores in the eggshell and a higher overall eggshell porosity.
• 6.6. The main problem posed by a high level of DDE would appear, however, not to be an excessive water loss from the egg during incubation, but rather eggshell thinning leading to a loss of the egg due to breakage in the nest.

     

Multiple hemoglobins in Triturus cristatus: their study by analytical isoelectrofocusing

• 1.1. Electrophoretic separation of the hemoglobin of healthy adult Triturus cristatus reveals four components.
• 2.2. Isoelectric focusing of the samee hemolysates in various commercial ampholytes of different chemical composition and pH range results in the separation of eight individual hemoglobin bands.
• 3.3. The bands obtained by electrophoresis are not homogeneous as revealed by individual gel electrofocusing. They finally separate into the same eight components, as in the whole hemolysate.
• 4.4. From the above findings it is concluded that this species has not four but eight individual hemoglobin molecular forms.
• 5.5. Our results demonstrate lack of hemoglobin polymorphism in this species.

     

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.

     

Toxicokinetics of xenobiotics in zebrafish—Comparison between tap and river water

• 1.1. Uptake and elimination of lindane, 3,4-dichloroaniline, phenol and 4-nitrophenol by the zebrafish Brachydanio rerio were investigated in tap water and in water of the river Rhine.
• 2.2. The differences in bioconcentration of chemicals between the two water types did not exceed a factor of 2.5.
• 3.3. Elimination kinetics were comparable in tap and river water.
• 4.4. It can be concluded that water of the river Rhine does not influence the kinetics of the investigated xenobiotics.