Inhibition of tubifex pyruvate kinase by storage phosphagens and adenosine triphosphate

• 1.1. Within the first 6–12 hr of experimental anaerobiosis the concentration of Tubifex phosphagens, phospholombricine and phosphoarginine, decrease to 10–30% of the values under aerobic conditions (7.5 and 3. μM/g dry wt).
• 2.2. High concentrations of both phosphagens (5–25 mM) inhibit Tubifex pyruvate kinase (PK) activity, the inhibitory mechanisms seem to be different. The inhibition is not mediated by the corresponding phosphagen kinases. Inhibition by phosphoarginine obviously requires an additional factor, which chemical nature is still unknown.
• 3.3. Certain phosphocreatine preparations also inhibit Tubifex PK. This inhibition, however, is likely due to contaminants than to phosphocreatine.
• 4.4. Mg-ATP demonstrates the strongest inhibitory effect on PK activity with a mixed competitive inhibition vs PEP and a non competitive vs ADP.

     

Cellular and intracellular localization of catalase and acid phosphatase in the midgut of Lumbricus terrestris L.: A cell fractionation study

• 1.1. Cellular and intracellular localization of catalase and acid phosphomonoesterase in the midgut of Lumbricus terrestris was studied by use of tissue fractionation.
• 2.2. At least 60–70% of the catalase resides in the chloragocyte cytosol and the remaining 30–40% resides in gut epithelium peroxisomes.
• 3.3. One of the main functions of the chloragocyte catalase is probably scavenging for H₂O₂ arising from the interaction between blood heme-protein and oxygen.
• 4.4. A simple method for the histochemical detection of cytosol catalase is proposed.
• 5.5. About 10% of the gut acid phosphatase resides in chloragocyte lysosomes. The chloragosomes contain no acid phosphatase.

     

Metals in the molluscan kidney: Uptake and subcellular distribution of 109Cd, 54Mn and 65Zn by the clam,Mercenaria mercenaria

• 1.1. Experiments were conducted to assess the relative tissue distribution of Cd, Mn and Zn accumulated by Mercenaria mercenaria from seawater using ¹⁰⁹Cd, ⁵⁴Mn and ⁶⁵Zn.
• 2.2. The kidney accumulated all three metals most extensively with Cd in particular showing the greatest degree of renal concentration.
• 3.3. Subcellular fractionation of the kidney showed that 34.3% of the ⁵⁴Mn, 5.6% of the ⁶⁵Zn and 1.3% of the ¹⁰⁹Cd had been incorporated into mineral concretions present in kidney cells.
• 4.4. Gel permeation chromatography of renal cytosol fractions showed the isotopes to be bound to macromolecules with mol. wt of approximately 60,000, 12,000 and 7500.

     

Blood volume recovery in hemorrhaged japanese quail

• 1.1. Blood volume and plasma biochemical changes and feed and water consumption in response to a hemorrhage by phlebotomy of 30% of the calculated total blood volume with and without replacement of blood volume with physiological saline were determined in juvenile male Coturnix coturnix japonica.
• 2.2. Plasma protein and osmolality decreased rapidly posthemorrhage and did not recover by 72 hr posthemorrhage.
• 3.3. Plasma glucose, Na⁺ and K⁺ increased within Ihr postphlebotomy. Plasma Na⁺ returned to nonphlebotomized levels within 6 hr postphlebotomy.
• 4.4. Saline replacement of blood volume resulted in hypervolemia within 3–5 min postphlebotomy.
• 5.5. Phlebotomized quail receiving no saline recovered blood volume to 0 hr (nonphlebotomized) levels within l hr postphlebotomy.

     

The effects of heavy metals and metabolic inhibitors on calcium uptake by gills and scales of Fundulus heteroclitus in vitro

• 1.1. Cadmium (Cd) and zinc (Zn) were inhibitory to calcium uptake by isolated gills of Fundulus heteroclitus in vitro. The metals appeared to act by displacing Ca²⁺ ions from protein carriers involved in facilitated diffusion.
• 2.2. In saltwater fish, transport of calcium across the serosal membrane of gill chloride cells is partly energy dependent and is likely mediated by Ca²⁺-ATPase. However, much of the calcium transport through the gill epithelium appears to occur by passive processes.
• 3.3. Cd (10⁻⁵M—10⁻³M) and Zn (10⁻⁷M—10⁻³ M) inhibited calcium uptake by isolated scale patches incubated in a physiological saline.
• 4.4. Cyanide, oubain, and quercetin treatment of scale patches produced results similar to those of the Cd and Zn treatments suggesting that metal-induced inhibition of ATPases may be responsible for reduced calcium transport by scale osteoblasts.

     

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.

     

The effect of salinity on coelomic fluid osmolyte concentration and intracellular water content in Luidia clathrata (Say) (Echinodermata: Asteroidea)

• 1.1. The concentrations (mM) of osmolytes in the coelomic fluid of Luidia clathrata kept at 25‰S seawater (control individuals) were: 345, Na⁺; 10, K⁺; 10, Ca²⁺; 44, Mg²⁺; 387, Cl⁻; 0.67, amino acids; 0.09, NH₄⁺.
• 2.2. When individuals were transferred from 25‰S to 15‰S or 35‰S, the concentrations of inorganic ions in the coelomic fluid usually equilibrated within 24hr and became the same as those in the medium.
• 3.3. The intracellular water content (g intracellular H₂O/g solute-free dry tissue) of the pyloric caeca and tube feet of control individuals throughout the experiment was 2.13 and 5.40, respectively.
• 4.4. In tissues of individuals transferred to 15‰S, the intracellular water content increased by an average 50% in 12 hr but returned to 19% above control levels during 1 week.
• 5.5. In tissues of individuals transferred to 35‰S, the intracellular water content decreased by an average 17% in 12 hr and did not change during 1 week.
• 6.6. Luidia clathrata is an osmoconformer and partial cell volume regulator within the seasonal salinity range it encounters.

     

An alkaline phosphatase from Thermus sp strain Rt41A

• 1.1. A thermostable orthophosphoric monoester phosphohydrolase (EC 3.1.3.1) from Thermus sp strain Rt41A has been purified 400-fold to give a specific activity of 25 U/mg at 60°C in IM diethanolamine (pH 11.1).
• 2.2. The enzyme has a M_r of 160,000 and is trimeric.
• 3.3. The half-life of the enzyme is 5 min at 85°C.
• 4.4. The enzyme has a wide specificity for a number of phosphate monoesters.
• 5.5. The H_m of the enzyme is pH dependent, so the pH optimum of the enzyme is affected by the substrate concentration.
• 6.6. The enzyme is inhibited 50% by 20 mM Ca²⁺ or Mg²⁺.
• 7.7. The K_i for phosphate, EDTA-di sodium salt and arsenate (in 1 M diethanolamine, pH 11.1) is approx 1.2, 1.6 and 4mM respectively.
• 8.8. Urea (200 mM) is not inhibitory.

     

Sodium-dependence of amino acid transport by the nephridia of Sabella pavonina (annelida,polychaeta)

• 1.1. In the absence of sodium, the reabsorption rate of amino acid α-aminoisobutyric acid (AIB) by the nephridia of Sabella pavonina is reduced to 20% and the AIB accumulation in the cells is reduced to 10%. These results suggest the presence of sodium-dependant processes.
• 2.2. The observed processes are reversible when control conditions are re-established.
• 3.3. A minimum of 17mEq/l Na⁺ is required to restore the normal reabsorption rate.
• 4.4. The addition ofamiloride (10⁻³⁵ M) decreases the reabsorption rate, but to a lesser extent than the absence of sodium.

     

Studies on prolonged spermatozoa survival in chiroptera—II. The role of zinc in the spermatozoa storage phenomenon

• 1.1. The mean annual Zn content of the sperm storage organs (uterus and epididymis) in Myotis velifer and M. lucifugus is two to three times higher than in corresponding tissues of other mammals.
• 2.2. The content of Zn in the sperm storage organs and male accessory glands has an annual cyclic pattern. Significant increases are recorded at prehibernation insemination (September) and posthibernation conception (April/May).
• 3.3. Zinc is present in the storage organs of bats throughout the spermatozoa storage phase of the reproductive cycle.
• 4.4. Zinc, due to its regulatory effects on spermatozoa (maturation, metabolism, motility) may be important in sperm storage in hibernating bats.

     

Effects of a purine inhibitor,allopurinol, on urate metabolism in the german cockroach,Blattella germanica L. (Dictyoptera: Blattellidae)

• 1.1. Adult male and female cockroaches (Blattella germanica) were maintained on a positive nitrogen balance diet (66% protein) containing various levels of allopurinol (0–3%) to determine the effects of allopurinol on urate synthesis and storage.
• 2.2. Each insect was injected with [¹⁴C]hypoxanthine and after 1 week was analyzed for whole-body hypoxanthine, xanthine and urate radiolabel.
• 3.3. There was a general trend of decreased whole-body radiolabel retention, radiolabeled body urates and total-body urate content in both sexes with increasing amounts of dietary allopurinol.
• 4.4. Virgin female adults were allowed to feed on diets containing 0, 25 and 66% protein plus 0.1% allopurinol and were injected with [¹⁴C]xanthine.
• 5.5. After 1 week radiolabel content in the whole-body xanthine and urate pools was determined.
• 6.6. Females on the 0% protein diets contained less radiolabel in the whole-body and body urates than those on either 25 or 66% protein diets.

     

Some physical and chemical properties of purified nematocysts of Hydra attenuata pall. (Hydrozoa,cnidaria)

• 1.1. A method for purifying undischarged nematocysts from Hydra and other cnidarians is described.
• 2.2. Isolated cysts (relative densities 1.22–1.24) evaginate their tubular content even after previous dehydration.
• 3.3. The cyst wall is permeable to dyes of mol. wts up to 600,000.
• 4.4. Approximately two-thirds of the cyst's dry wt are soluble proteins. Eighty per cent of them are of low mol. wt and highly anionic, presumably serving as binding sites for Ca²⁺ and Mg²⁺.
• 5.5. The other 20% includes 30 different proteins amongst them toxins and enzymes (phospholipase and little proteases but no collagenase, chitinase or hyaluronidase).

     

The effect of eyestalk ablation on growth,haemolymph composition and gill Na+, K+-ATPase activity of Penaeus monodon juveniles

• 1.1. Eyestalk unablated and unilaterally ablated Penaeus monodon juveniles had survival rates after 5 months of 75–72.5 and 67.5–60%, respectively.
• 2.2. Unilaterally ablated shrimps had significantly higher (P < 0.05) growth rate than unablated shrimps.
• 3.3. Eyestalk-ablatement resulted in a decrease in the haemolymph sodium concentration and an increase in the potassium and calcium concentration of shrimps.
• 4.4. The osmolarity of haemolymph and total protein concentration of unablated shrimps were demonstrated to be higher than those of unilaterally ablated shrimps.
• 5.5. The eyestalk-ablated shrimps possess higher total ATPase and Na⁺,K⁺-ATPase activities in the gill than those of unablated shrimps.

     

The digestive enzymes of the pacific brown shrimp Penaeus californiensis.: I—Properties of amylase activity in the digestive tract

• 1.1. Crude extract of the whole digestive tract from the brown shrimp (P. californiensis) was investigated for digestive amylase activity.
• 2.2. Considerable amylase activity was found at pH 6.5–8.0, with optimum pH at around 7.5.
• 3.3. Optimum temperature was found between 30–40°C, similar to amylases from other crustaceans.
• 4.4. Amylase activity was highly halotolerant, having 50% maximum activity at 3 M NaCl.
• 5.5. Maximum amylase activity was found at 0.01 M NaCl.
• 6.6. Amylase activity was partially inhibited by the divalent ions Hg²⁺, Zn²⁺, Cu²⁺ and Cr²⁺.
• 7.7. Mg²⁺ and Ca²⁺ ions seemed to enhance amylase activity.

     

Fermentation and the production of volatile fatty acids in the alimentary tract of the rock hyrax,Procavia capensis

• 1.1. Aspects of ruminant-like metabolism were examined in the hyrax Procavia capensis.
• 2.2. High concentrations of volatile fatty acids occurred in the cardiac stomach with a predominance of acetic and lactic acids.
• 3.3. Acetic (69%), propionic (22%) and butyric (8%) acids occurred in highest concentrations in the proximal caecum, with appreciable amounts in the proximal colon, distal caecum and appendices.
• 4.4. The depot fat contained high proportions of unsaturated C₁₈ (linoleic and linolenic) acids.
• 5.5. The glucose level in the plasma was within the range established for non-ruminant herbivores.
• 6.6. The possibility of silage-like fermentation occurring in the cardiac stomach is discussed.

     

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.

     

Reabsorption and accumulation of α-amino-iso-butyric acid in the nephridia of Sabella pavonina Sa vigny (Annelida polychaeta)

• 1.l. High amino acid concentrations were found in the anterior coelomic fluid of a Polychaeta (Sabella pavonina Savigny).
• 2.2. The concentrations being much higher in the fluid which penetrates the nephrostomia into the nephridia lumen than in the final urine indicates that the nephridia reabsorbs large amounts of amino acids.
• 3.3. Nephridial perfusion experiments showed that an amino acid analogue (α-amino-iso-butyric acid, AIB) is transported by the nephidia.
• 4.4. The transport took place across the nephridial wall owing to the presence of a carrier-mediated transport system and a diffusion system.
• 5.5. For the carrier-mediated transport, the V_max was 0.234 ± 0.025 nmol·min⁻ and the K_m 3.715 ± 0.315mmol·l⁻.
• 6.6. AIB accumulated in the nephridial cells up to a maximum rate of 01.17 nmol·min⁻.
• 7.7. Intracellular accumulation stopped increasing when the V_max for reabsorption was reached.
• 8.8. These results indicate that the carrier-mediated transport of AIB is located at the apical membrane of the nephridial cell, and that AIB transport by simple diffusion takes place through the paracellular pathway.

     

Demonstration of specific receptors for calcitonin in isolated trout gill cells

• 1.1. Salmon calcitonin binding by isolated gill cells from rainbow trout, Salmo gairdneri has been investigated.
• 2.2. The calcitonin receptor interaction is time- and temperature-dependent.
• 3.3. 50% of inhibition of the ¹²⁵I labeled calcitonin binding is observed in presence of 1.5 ng/ml unlabeled salmon calcitonin.
• 4.4. Two types of receptors are described: a high affinity-low capacity site and a low affinity-large capacity site.
• 5.5. These studies strongly support the role of calcitonin as a hormone regulating the gill function in physiological conditions.

     

Preparation and characterization of biotinylated probes for the β-interferon receptor

• 1.1. Recently we described the isolation of the β-interferon receptor [Zhang et al. (1986) J. biol. Chem. 261, 8017–8021]. A highly purified product was obtained but in low quantities.
• 2.2. The use ofbiotinylated β-interferon as a ligand represents an alternate approach to receptor isolation.
• 3.3. We have prepared and characterized the derivatives N-(biotinyl)- and N-(biotinyl-ϵ-aminocaproyl)-recombinant human [Ser¹⁷-interferon β (B- and BC-recHulFNβ).
• 4.4. Biotin incorporation does not result in any loss of antiviral activity, demonstrating the recognition of the derivative by the cell receptor.
• 5.5. The biotinylated recHuIFNβ binds specifically and reversibly to succinoylavidin or guanidine thiocyanate-stripped succinoylavidin linked to a Sepharose matrix.
• 6.6. Comparison of the competition curves obtained with [¹⁴C]biotin and [³H]biotinyl recHuIFN, in the presence of increasing concentrations of biotin suggests that the IFN moiety of the derivative has little effect on the affinity of biotin for avidin.
• 7.7. Biotinylated recHuIFNβ derivatives represent useful probes for the β-IFN receptor.

     

Evidence of presence of a low molecular weight,non-metallothionein-like metal-binding protein in the marine gastropod Nassarius reticulatus L.

• 1.1. A low molecular weight metal-binding protein was found in the snail Nassarius reticulatus cytosol, which was induced in heavy metal contaminated environments.
• 2.2. In our sodium dodecyl sulfate-mercaptoethanol polyacrylamide gel systems it behaved as a protein of 19 kDa mol. wt.
• 3.3. Amino acid composition studies definitely established this protein not to be metallothionein (Mt) like, because it had a much lower level of cysteine and substantial amounts of aromatic amino acids and histidine.
• 4.4. The metal-binding strength of this protein was concluded to be much weaker than that of Mt.
• 5.5. In the crustacean Pagurus bernhardus L. such a protein could not be demonstrated.
• 6.6. In both the snail and the crustacean Zn may inhibit the accumulation of Hg. The premise for studying the induction of the metal-binding Nassarius protein as a supplement to environmental metal monitoring purposes is briefly discussed.