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.

     

Hemoglobin-containing cells of Neodasys (gastrotricha,chaetonotida)—II. Respiratory significance

• 1.1. The properties of the intracellular hemoglobin of Neodasys sp. are described and the utility of the hemoglobin in oxygen transport and storage is considered.
• 2.2. The hemoglobin is located in immobile cells which occupy 14% of the total body volume. Heme concentration in these cells was 18.5 mM and the oxygen p50 (in vivo) was approximately 1.0 mmHg.
• 3.3. It is argued that oxygen storage is the most likely function of Neodasys hemoglobin. A simple geometric argument indicates that body wall oxygen transport is not greatly improved by facilitation.
• 4.4. Respiratory function in Neodasys is compared with that in a related gastrotrich, Turbanella, which is morphologically similar and is sympatrie, but does not possess hemoglobin.

     

Characterization of hemoglobin from Phoronis architecta (phoronida)

• 1.1. Phoronis architecta hemoglobin is composed of four distinct hemoglobin subunits with minimum MW's of 16–17,000 or 17–19,000 daltons. All four hemoglobins are monomeric when oxygenated. Two of the monomers combine to form dimers when bound with carbon monoxide.
• 2.2. In cellulo, Phoronis architecta hemoglobin has a half-saturation (P₅₀) value of 1.3 ± 0.1 mm Hg, shows cooperative oxygen binding (Hill coefficient = 2.7 ± 0.3), and no Bohr effect from pH 6.6 to 7.9. In vitro, the hemoglobin has a P₅₀ of 0.76 ± 0.21 mm Hg but shows no cooperativity (0.90 ± 0.15 (SD)).
• 3.3. The oxygen dissociation constant (K_off) from hemoglobin is 2.7 ± 0.2 sec⁻¹, and the computed oxygen association constant (K_on) is 2.5 × 10⁶ M⁻¹ · sec⁻¹ (1.9–3.6 × 10⁶ M⁻¹ · sec⁻¹).

     

Glucose transport across the intestinal wall of the freshwater snail Biomphalaria glabrata

• 1.1. Isolated midguts of the freshwater snail Biomphalaria glabrata were mounted in an incubation chamber in saline containing 2 mM glucose and perfused with the same solution. External and internal media were continuously gassed with carbogen gas (95% O₂, 5% CO₂). In order to measure the flux rates of glucose [¹⁴C]glucose was applied in the perfusion medium or in the incubation medium. Net fluxes of glucose were calculated as the differences between unidirectional in- and effluxes.
• 2.2. A directed net flux from the mucosal to the serosal side of the intestine was demonstrated (mucosal to serosal = 50 ± 10 nmol cm⁻²hr⁻¹(N = 6) serosal to mucosal 7 ± 1 nmol cm⁻²hr⁻¹ (N = 6), net flux = 43 nmol cm⁻²hr⁻¹).r
• 3.3. The active transport of glucose was reduced by the presence of metabolic inhibitors, cyanide (1 mM) and dinitrophenol (1 mM) on the mucosal as well as on the serosal side. Ouabain (1 mM) inhibited the transport rate only when it was added on the serosal side. Amiloride (1 mM) had no effect on the transport rate whether added on the mucosal or on the serosal side.
• 4.4. Inhibition of glucose transport by oubain, a specific inhibitor of Na⁺/K⁺-ATPase, suggests that glucose transport is secondary active and coupled to Na⁺-transport.

     

Mg2+-dependent (Na+ + K+)- and Na+-ATPases in the kidneys of the gilthead bream (Sparus auratus L.)

• 1.1. The (Na⁺ + K⁺)- and Na⁺-ATPases, both present in kidney microsomes of Sparus auratus L., have different activities and optimal assay conditions as, in the first of the two stocks of fish used (A), the spec. act. of the former is 51.7 μmol P_i mg prot⁻¹ hr⁻¹ at pH 7.5, 100 mM Na⁺, 10 mM K⁺, 17.5 mM Mg²⁺, 7.5 mM ATP and that of the latter is 6.5 μmol P_i mg prot⁻¹ hr⁻¹ at pH 6.5, 40 mM Na⁺, 4.0 mM Mg²⁺, 2.5 mM ATP.
• 2.2. Ouabain and vanadate specifically inhibit the (Na⁺ + K⁺)-ATPase but not the Na⁺-ATPase that is preferentially inhibited by ethacrynic acid.
• 3.3. While the (Na⁺ + K⁺)-ATPase is strictly specific for ATP and Na⁺, Na⁺-ATPase can be activated by various monovalent cations and, apart from ATP, hydrolyses CTP, though less efficiently.
• 4.4. The second stock B, subjected to higher salinity than A, shows an acidic shifted Na⁺-ATPase optimal pH, opposed to the stability of that of the (Na⁺ + K⁺)-ATPase, a decreased (Na⁺ + K⁺)-ATPase and a strikingly depressed Na⁺-ATPase.
• 5.5. The results are compared with literature data and discussed on the basis of the presumptive different roles as well as functional prevalence in various salinities of the two ATPases.

     

A comparative study of the respiratory properties and physiological function of haemocyanin in two burrowing and two non-burrowing crustaceans

• 1.1. Oxygen dissociation curves were constructed for the haemolymph of two non-burrowing, Galathea strigosa and Eupagurus bernhardus, and two burrowing crustaceans, C. cassivelaunus and Nephrops norvegicus. The p₅₀ at in vivo pH values and 10°C was 12.6 Torr in G. strigosa, 23 Torr in E. bernhardus, 3.1 Torr in C. cassivelaunus and 11.5 Torr in N. norvegicus.
• 2.2. The Bohr values (Δlogp₅₀/ΔpH) were high in all species ranging between −0.96 and −1.48. Cooperativity expressed as P₅₀ averaged 3.3, 3.8 and 3.8 in G. strigosa, E. bernhardus and N. norvegicus. respectively. A lower value of 2.2 was observed in C. cassivelaunus.
• 3.3. The oxygen affinity of the haemocyanin was relatively temperature independent, the values for ΔH at pH7.9 ranging between −5.1 and −18.1 kJmol⁻¹.
• 4.4. Haemolymph respiratory gas analysis showed values similar to those previously reported in crustaceans: p_aO₂ ranging between 44 and 107 Torr and p_vO₂ values between 18 and 24 Torr.
• 5.5. Pre-/post-branchial pH differences were small in G. strigosa, E. bernhardus and N. Norvegicus, but averaged 0.09 of a pH unit in C. cassivelaunus. p_aCO₂ and P_vCO₂ values ranged between 1.4 and 2.3 Torr.
• 6.6. In buried C. cassivelaunus both pre- and post-branchial oxygen tensions decreased, as did oxygen tension overall during respiratory pauses.
• 7.7. Cardiac output values were low, ranging between 59 and 71 ml kg⁻¹ min⁻¹ for all four species and calculated stroke volumes were realistic in terms of animal size.
• 8.8. In the non-burrowing species physically dissolved oxygen accounted for 5–21% of the oxygen transported to the tissues. In the burrowing species values of 40–77% were found.

     

Bioelectrical potentials across the mantle epithelium of Achatina fulica

• 1.1. The shell side of the mantle of Achatina fulica is several millivolts positive to the blood side in vitro.
• 2.2. The electrical potential does not depend on Na⁺, Ca²⁺, Mg²⁺, K⁺ or HCO₃⁻ but requires the presence of chloride on the shell side.
• 3.3. The potential difference and short-circuit current ranged from 3.0 to 30.0 mV and 15.0 to 75 μA/cm² with averages at 10m V and 50 μA/cm² respectively.
• 4.4. The electrical gradient is reduced by 2,4-dinitrophenol, thiocyanate and furosemide but not by ouabain, CO₂ or acetozolamide.
• 5.5. It is suggested that the nature and mechanism of electrogenesis in Achatina parallels that of the Helix mantle.

     

Preparation of two neurotoxic esterases from the chick central nervous system

• 1.1. A standard procedure for lipid-extraction of lyophilized hen brain material is decribed.
• 2.2. Nine carboxylesterase isoenzymes (EC 3.1.1.1) are identified in lipid-extracted lyophilized material (LELM) using kinetic analysis of organophosphate inhibition. Total phenyl valerate (PV) hydrolysing carboxylesterase activity in LELM is 43.3U.g⁻¹
• 3.3. Two carboxylesterase isoenzymes of LELM are classified as neurotoxic esterases (NTE_A and NTEg_B).
• 4.4. Using n-octylglucoside 51% of the water-insoluble neurotoxic esterase activity from LELM are solubilized.
• 5.5. Six carboxylesterase isoenzymes including NTE_A (6.5 U-l⁻¹) and NTE_B (4.2 U-l⁻¹) are present in the solubilized preparation.
• 6.6. Throughout purification and separation steps carboxylesterase isoenzymes are identified by their rate constants for the reaction with organophosphorus inhibitors.

     

Blood changes in japanese eels,Anguilla japonica,experimentally infected with typical or atypicalAeromonas salmonicida

• 1.1. Changes in the blood and in the rate of oxygen consumption of Japanese eels injected intramuscularly in the head with a lethal dose of typical or atypical Aeromonas salmonicida at 20°C were investigated.
• 2.2. Eels infected with the bacteria became moribund within 4 to 6 days, and then died within 1 day.
• 3.3. The O₂ consumption rate and blood parameters changed markedly with infections. The responses of hosts to infection by the two kinds of bacteria differed with regard to the following four points: blood pH, plasma Cl⁻, lactic acid, and the numbers of granulocytes and lymphocytes.
• 4.4. The responses of eels infected with atypical A. salmonicida were larger and more rapid than those of eels infected with typical A. salmonicida.

     

Comparative study of the oxyhaemoglobin dissociation curve of four mammals: Man,dog, horse and cattle

• 1.1. The entire oxygen dissociation curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this curve, have been compared in four mammalians: man, dog, horse and cattle.
• 2.2. If the oxyphoric capacities are similar between these species (around 1.39ml O₂/gHb), their P50, measured in standard conditions, i.e. at pH 7.4;.pCO₂ 40mmHg and T 37°C, varies between 23.8 (± 0.8) mmHg for the horse, 25.0 (± 1.4) mmHg for cattle, 26.6 (± 1.2) for man and 28.8 (± 2.6) mmHg for the dog.
• 3.3. The higher dispersion of the dog's P50 is due to difference between breeds; in seven breeds investigated, the P50 ranges from 25.8 (spaniel) to 35.8 (hound).
• 4.4. We noted no sex difference in the four species.
• 5.5. The DPG level is confirmed to be low in cattle (< 1 μmol/gHb) as compared to man (13.5 ± 2.1 gmmol/gHb), horse (16.9 ± 1.1 gmmol/gHb) and dog (19.4 ± 2.8 μmol/gHb).
• 6.6. The oxygen exchange fraction defined as the difference in vol% between a pO₂ of 80 and 35 mmHg is, respectively, 3.6 (± 0.6) vol% for cattle, 4.0 (0.4) vol% for the horse, 5.5 (± 0.5) vol% for man and 6.6 (± 1.7) vol% for the dog.
• 7.7. The position and shape of the ODC, as well as T, DPG and pH effects, indicate that the haemoglobin of man and dog seem better adapted to O₂ delivery as compared to the horse and cattle.

     

Purification and properties of tetralysine endopeptidase from Escherichia coli AJ005

• 1.1. A new tetralysine endopeptidase from Escherichia coli AJ005 has been purified about 135-fold.
• 2.2. The peptidase seems to be specific to tetralysine among lysine homopolymers.
• 3.3. The optimal pH was about 7.5
• 4.4. The activity was inhibited by KCN but not inhibited by soybean trypsin inhibitor.
• 5.5. The apparent K_m value was 2.5 × 1O⁻³ M for tetralysine.

     

The pH dependence of the affinity,kinetics and cooperativity of ligand binding to the root effect haemoglobin of the goldfish Carassius auratus

• 1.1. The binding of O₂ to goldfish haemoglobin showed a strong pH dependence P₅₀=5.5 mmHg; n = 2.4 at pH 8.0 and P₅₀ = 170 mmHg; n = 1.0 at pH 5.5 such that the protein is only 50% saturated in a solution of air equilibrated buffer at pH 5.5.
• 2.2. The binding of CO is cooperative at high pH (n = 2.8; L = 1000; K_R = 0.1 μM; K_T = 4 μM) and non-cooperative (n = 1) at pH 5.5.
• 3.3. The rate of O₂ dissociation is extremely fast and pH dependent; being 30 sec⁻¹ at pH 8.0 and 400 sec⁻¹ at pH 6.0 at 1°C. At 23°C the rate of this process is too fast to obtain accurate data using stopped-flow techniques.
• 4.4. Partial photolysis of the oxyhaemoglobin species leads to homogeneous recombination kinetics at pH 8.0 with an associated rate constant of 4.7 × 10⁷ M⁻¹ sec⁻¹. At pH < 7.5 the recombination process occurs in two steps. One rate is equal to that observed at pH 8.0. The slower process is favoured at low pH.
• 5.5. Photolysis of the CO haemoglobin complex indicates that, at high pH, combination of CO with deoxyhaemoglobin is cooperative, whilst recombination with Hb(CO)₃ is non-cooperative and occurs at a rate of 1.2 × 10⁶ M⁻¹ sec⁻¹.
• 6.6. At neutral pH recombination of CO with partially linganded haemoglobin occurs in a two-step process. The proportion contributed by each of these two steps in pH dependent.
• 7.7. The functioning of this Root effect haemoglobin is discussed in terms of the two state-model of cooperativity in which the αβ chain heterogeneity is minimal

     

Measurement of blood flow to osseous tissue in dogs using the radiolabelled microsphere method

• 1.1. The purpose of this study was to examine bone blood flow in various intra- and extra-oral sites.
• 2.2. The radiolabelled microsphere method was utilized to assess osseous blood flow in the following regions of 10 dogs: rib, long bone, and anterior and posterior regions of the maxilla and mandible.
• 3.3. Samples of cancellous and cortical bone were also obtained from each of these regions with the exception of the maxilla and the anterior mandible.
• 4.4. Mean blood flow ranged from 3.71 ±0.81 (SE) ml min.⁻¹ 100 g⁻¹ in the mandibular posterior cortical bone to 22.7±4.66ml min⁻¹ 100 g⁻¹ in the cancellous rib samples.
• 5.5. Blood flow to the cancellous tissue of the rib was significantly greater (P < 0.05 ) than the other tissues with the exception of maxillary posterior bone and cortical rib.
• 6.6. Results from this study indicate that blood flow to the maxillary posterior bone is relatively high, but blood flow in other intraoral osseous sites is significantly less than that of cancellous rib bone.

     

Nacl flux in the flounder (Pseudopleuronectes americanus) intestine: Effects of ph and transport inhibitors

• 1.1. The effects of extracellular pH on Na⁺ and Cl⁻ absorption were studied in vitro in the small intestine of the winter flounder, Pseudopleuronectes americanus.
• 2.2. Reductions in bathing solution pH inhibited J_ms^na (mucosal-to-serosal flux) and J_net^na (net flux) (r = 0.90) and J_net^Cl (r = 0.92) [due to an increase in J_sm^Cl, (serosal-to-mucosal)] and decreased short circuit current (Isc).
• 3.3. Luminal bumetanide (0.1 mM) and amiloride (1 mM) inhibited Na⁺ and Cl⁻ absorption by reducing J_ms.
• 4.4. Luminal barium (5mM) and luminal copper (100 μM) decreased J_ms^Cl and increased J_sm^Cl.
• 5.5. We conclude that reductions in extracellular pH inhibit a luminal membrane NaCl absorptive process (Na⁺-K⁺-2Cl⁻) and stimulate an electrogenic Cl⁻ secretory process.

     

Hypoxia adaptation in the crayfish procambarus clarki

• 1.1. P. elarki is an oxyconformer, with an oxygen uptake rate of 144 ± 4 μl/g wet wt/hr at oxygen tensions above 90% saturation and an uptake rate of 18 ± 3 μl g wet wt/hr at 15 torr.
• 2.2. Between 159 and 40 tort, blood pH decreases slightly from 7.77 ± 0.03 to 7.65 ± .04, and at 15 torr, blood pH drops to 7.36 ± 0.06.
• 3.3. At normoxia, blood lactate levels are low at 0.66 ± 0.01 mM/l blood. After 2 and 5 hr exposure to 15 tort, blood lactate levels increase to 3.29 ± 0.47 and 8.91 ± 0.14 mM/l blood, respectively. Upon return to normoxia, blood lactate levels decrease and are comparable to normoxic controls after 13 hr.
• 4.4. During mild hypoxia, P. elarki maintains adequate oxygen transport by utilizing a high O₂ affinity hemocyanin in conjunction with a low metabolic demand by its tissues.

     

Ionic dependence and vanadate sensitivity of (Na+, K+)-ATPase isolated from branchial sac of ascidians

• 1.1. Ion dependence and vanadium-induced inhibition on branchial sac ATPase in five species of ascidian Phlebobranchiata (vanadium-accumulating) and Stolidobranchiata (iron-accumulating) were studied.
• 2.2. The ATPase was obtained from the microsomal fraction, which was prepared from each ascidian branchial sac.
• 3.3. The ATPase was dependent on Mg²⁺ and activated by exogenous Na⁺ + K⁺.
• 4.4. Ouabain inhibited the ATPase activity in vitro, 10 μM to 100 μM vanadate, in vitro, suppressed the (Na⁺, K⁺)-ATPase.

     

Determination of benzo(a)pyrene in isopods (Porcellio scaber Latr.) exposed to contaminated food

• 1.1. A method is presented for the determination of the polycyclic aromatic hydrocarbon benzo(a)pyrene (BaP) in the isopod Porcellio scaber, using reversed-phase HPLC with fluorescence detection.
• 2.2. This technique has a detection limit for BaP in P. scaber of approximately 3.2 ng g⁻¹ fresh weight.
• 3.3. BaP was assimilated from food by P. scaber.
• 4.4. After four weeks of ad libitum feeding on BaP-contaminated food, concentrations in the isopods were approximately 30–40 times lower than those in the food.
• 5.5. Male and female isopods did not differ in BaP concentration. Variation among males seemed to be much higher than among females.

     

The mechanism of interaction of ceruloplasmin with superoxide radicals

• 1.1. The mechanism of interaction of CP with O₂ radicals in chemical and enzymatic systems of Superoxide radical generation as well as in the pulse radiolysis technique was studied.
• 2.2. It is found that CP does not exert any kinetic influence on the decomposition of Superoxide radical and, unlike SOD, cannot catalyze the reaction of disproportionation of these radicals in systems with chemical and enzymatic generation of O₂⁻.
• 3.3. The data obtained confirm the suggestion that CP interacts with precursors of ₂⁻ radicals.
• 4.4. The irradiation of CP does not change its inhibiting activity in the reaction of the formation of Superoxide radicals in systems with enzymatic O₂⁻ generation, but decreases its oxidase activity.
• 5.5. The results obtained demonstrated that the increase in the radiation dose resulted in the decrease of the inhibiting activity of SOD, whereas the activity of CP did not change.

     

The dynamics of the permeation of an analogue of insect juvenile hormone into nematodes

• 1.1. ¹⁴C-dichlorofarnesoate permeated rapidly into Haemonchus contortus (infective juveniles) and Panagrellus redivivus (mixed cultures) and was strongly bound by hydrophobic association (K_s > 10⁻⁴M).
• 2.2. Uptake rose linearly with increases in temperature (5–38°C) and external concentration (C₀; 0.07–2.15 × 10⁻⁴ M). Within 1 hr the internal concentration, C₁ was >C C₀.
• 3.3. The pH of the medium (6–8) did not affect uptake.
• 4.4. Efflux of dichlorofarnesoate was low: the half-time of release was > 18 hr.
• 5.5. The uptake curve approximated to the expression C₁/C₀ = a(1 − e^−bt) with a and b as constants and t in hr.
• 6.6. These results clarify previous work on the inhibitory action of juvenile hormone on the development of nematodes.

     

Purification and properties of an ld-dipeptidase FROM Bacillus sphaericus

• 1.1. An ld-dipeptidase (EC 3.4.13.-) that hydrolyzes the unrelated dipeptides l-Ala-d-Glu (sp. act. 0.85 μmol·min⁻¹·mg⁻¹) and l-Lys-d-Ala (sp. act. 11 μmol · min⁻¹·mg⁻¹) has been purified 250-fold from the sporulation medium of Bacillus sphaericus with a 4% recovery of lytic activity.
• 2.2. Throughout the purification steps, followed with both substrates, the enzyme peaks of activities were congruent and the ratios of activities were constant. Both activities were activated 50-fold by cobalt. Polyacrylamide gel electrophoresis of the final preparation showed the two enzyme activities to be coincident. The data are consistent with those activities being due to a single enzyme.
• 3.3. Sodium dodecylsulfate polyacrylamide gel electrophoresis of the purified enzyme showed a single protein band (M_r 38,000).
• 4.4. This dipeptidase hydrolyzes some other ld-dipeptides with a free amino and carboxyl group. Although dipeptides having a di-amino acid as the amino terminus are the best of the substrates tested, the hydrolysis occurs also when neutral amino acids are N-terminal. The activity is higher with neutral C-terminal residues such as Gly or d-Ala than with a di-acid residue such as d-Glu.
• 5.5. This enzyme may have a function in peptidoglycan metabolism.