Effect of polyunsaturated fatty acids on the growth of fish cells in culture

• 1.1. The effects on growth of supplementing the medium with (n-3) and (n-6) polyunsaturated fatty acids (PUFA) were investigated in Atlantic salmon (AS) and turbot (TF) cell lines.
• 2.2. Neither cell line grew in the absence of serum, and addition of increasing percentages of serum resulted in graded increases in cell growth in both cell lines.
• 3.3. The growth of AS cells was stimulated by supplementing the medium with both (n-6)PUFA and (n-3)PUFA at 5–25 μM, especially 18:3(n-3) and 20:5(n-3).
• 4.4. Intermediate concentrations (15–20 μM) of 18:2(n-6) and 18:3(n-3) increased cell growth in TF cells, although only after 8 days in culture.
• 5.5. In contrast, both (n-3) and (n-6)PUFA at 25 μM tended to inhibit the growth of TF cells, and in longer incubations caused cell death.
• 6.6. The inhibition of TF cell growth rate and, in particular, the cell death induced by 25 μM PUFA could be abolished by the addition of vitamin E to the medium.

     

Biphasic action of growth hormone on intestinal amino acid absorption in striped bass hybrids

• 1.1. Weekly injections of bovine growth hormone (bGH) increased the maximal transport rate of both Na⁺-dependent and Na⁺ -independent l-leucine transport with little effect on the affinity constants in the intestine of striped bass hybrids.
• 2.2. The Na⁺-dependent and the Na⁺-independent transport of the non-metabolizable analog cycloleucine was also stimulated by bGH.
• 3.3. The Na⁺ -dependent active transport was stimulated 2 days after the hormone treatment, while the stimulation of the Na⁺-independent diffusional transport was not observed until after 2 weeks of treatment.
• 4.4. Studies of intestinal morphometry and l-leucine transport using brush border membrane vesicles suggested that bGH affects intestinal amino acid absorption initially by increasing the number of transporters per cell.
• 5.5. This phase is followed by a general increase of the intestinal mass after long-term treatment with the hormone.

     

Sodium transport in red blood cells of lamprey LAmpetra fluviatilis

• 1.1. Unidirectional Na⁺ influx in lamprey red blood cells was determined using ²²Na as a tracer.
• 2.2. Total Na⁺ uptake and amiloride-inhibitable Na⁺ influx increased in a saturable fashion as a function of external Na⁺ concentration (Na_e).
• 3.3. At 141 mM Na_e, the average value of net Na⁺ influx was 13 ± 1.1 and the amiloride-sensitive Na⁺ influx was 5.3±1.1 mmol/l cells per hr (±SE).
• 4.4. The amiloride-sensitive component of Na⁺ influx was significantly activated by 10⁻⁵ M isoproterenol, by 2 × 10⁻⁵ M DNP, and by cell shrinkage.
• 5.5. Furosemide (1 mM) had no effect on the Na⁺ transport in red cells.
• 6.6. The residual amiloride-insensitive component of Na⁺ transport was a linear function of Na_e in the range of 5–141 mM. This transport seems to be accounted for by simple diffusion.

     

Changes of the fatty acid composition in smolts of masu salmon (Oncorhynchus masou), associated with desmoltification and sea-water transfer

• 1.1. Tissue lipid compositions of desmoltified yearlings of masu salmon (Oncorhynchus masou) obtained by keeping smoltified fish in fresh water, were examined and compared to those of smoltified fish before and after transfer to sea-water (SW).
• 2.2. Lipid contents of muscle, liver, gut and gills of desmolts tended to increase compared to those of initial smolts.
• 3.3. The increased proportion of triacylglycerol (TG) and decreased proportion of phospholipids (PL) characterized the tissue lipids of desmolts.
• 4.4. Liver and muscle lipids showed no distinct differences both in content and proportion between initial and SW smolts, but gut and gill lipids of SW smolts decreased in content accompanied by a decrease of TG and an increase of PL in proportion.
• 5.5. Excepting muscle non-polar lipids, tissue lipids of desmolts contained more mono-unsaturated fatty acids and saturated fatty acids and less polyunsaturated fatty acids (PUFA), especially (n-3) PUFA such as 22:6(n-3), than those of initial and SW smolts.
• 6.6. No large differences in fatty acid composition were seen between initial and SW smolts except for the gut.
• 7.7. The proportion of (n-3) PUFA in the gut of SW smolts was higher than that of initial smolts.
• 8.8. The results indicated that masu salmon smolts can modify their lipid metabolism to adapt to ambient salinity changes. The proportion of (n-3) PUFA particularly in polar lipids, or in osmoregulatory organs such as gut and gills, was seen to be critical in lipid types of freshwater- or sea-water-adapted fish.

     

Protein digestion and ion concentrations in rainbow trout (Salmo gairdnerii Rich.) digestive tract in sea- and fresh water

• 1.1. Rainbow trout maintained in fresh water or Actapted to sea-water for 24 hr were fed casein-based dry diet. After feeding, fish were kept in fresh water (FW) or transferred to artificial sea-water (SW) and sacrificed after 10 or 20 hr.
• 2.2. The digestive tract was separated into five parts: stomach, pyloric caeca region, middle intestine and two equal lengths of rectum.
• 3.3. The content of these parts was analysed for ions Na⁺, K⁺, Cl⁻, Mg²⁺ and for free, peptide and total amino acids.
• 4.4. In the fish stomach all ions, with the exception of Ca²⁺, indicate drinking of sea-water. In the pyloric caeca region Na⁺ appears to be efficiently absorbed in SW fish but influxed in FW fish. In the rectum of SW fish K⁺ appears to be reabsorbed but Na⁺ concentrated in faeces.
• 5.5. Free amino acid concentrations were always higher in gut lumen of SW than in FW fish in respect to time after feeding and portion of intestinal content. Free amino acids constitute at most 7.4–8.7% of total amino acids in the content of pyloric caeca region.
• 6.6. Peptide amino acids, being mostly di-, tri- and tetra-peptides, increased in stomach content from 14.7 to 28.4% of the total, from 6 to 10 hr after a meal in SW fish. Peptide amino acids constituted 80.3–89.0% of total amino acids in intestinal content of the pyloric caeca region. These peptide portions decreased in the mid-intestine (47.5–52.5%) and increased again in the rectum (73.6–76.0%).
• 7.7. It was concluded that in rainbow trout fed in both sea- or fresh water, ion concentrations do not seem to interfere with protein digestion and nutrient absorption in alimentary tract.

     

Crayfish retinular cells: Influence of extracellular sodium and calcium upon receptor potential

• 1.1. In crayfish, light stimulation of the retinular cells induces a depolarizing receptor potential.
• 2.2. Experiments were designed to determine the role of Na⁺ and Ca²⁺ on receptor potential during dark And light states.
• 3.3. Depolarization depends on Na⁺ and Ca²⁺ availability to the retinular cell.
• 4.4. Repolarization velocity and response duration depend on extracellular Ca²⁺ availability.
• 5.5. Light adaptation increases receptor potential dependence on calcium and sodium ions.
• 6.6. We analyse these results with respect to other invertebrate photoreceptors.

     

Driving forces for the uphill transport of amino acids into epidermal brush border membrane vesicles of the sea anemone,Anemonia sulcata (Cnidaria,anthozoa)

• 1.1. The transport of amino acids into membrane vesicles prepared from epidermal tentacle tissue of the sea anemone, Anemonia sulcata, depends on an electrochemical potential difference caused, e.g. by sodium chloride gradients.
• 2.2. Potassium or choline chloride gradients energized the transport less effectively than sodium chloride gradients. Both Na⁺-ions and Cl⁻-ions were required for the amino acid transport.
• 3.3. The uphill transport of amino acids along the downhill movement of driver ions (sodium chloride gradient conditions) was characterized by an overshoot; under sodium chloride equilibrium conditions, however, an accumulation of amino acids within the vesicles could not be measured.
• 4.4. Potassium diffusion potentials in combination with valinomycin indicated that hyperpolarization (vesicle inside negative) and hypopolarization (vesicle inside positive) enhanced or depressed the accumulation of amino acids within the vesicles.
• 5.5. Being at the phylogenetic base of the Eumetazoa, cnidarians show characteristics for the transmembrane transport of amino acids comparable to those established for vertebrates.

     

Effects of long- and medium-chain triglycerides on amino acid uptake in rat intestinal brush border membrane vesicles

• 1.1. Uptake of l-leucine, l-phenylalanine, l-proline and l-lysine into brush border membrane vesicles from rats fed either a medium-chain triglyceride (MCT) or a long-chain triglyceride (LCT) diet was studied under conditions of the presence or absence of a Na⁺ gradient.
• 2.2. From the results of initial rate, Na⁺-dependent transport in LCT feeding were lower than in feeding MCT. The Na⁺-independent transport did not vary in either group except for l-lysine uptake.
• 3.3. For l-leucine, l-phenylalanine and l-proline in Na⁺ dependence, kinetic analysis revealed 4–6-fold smaller V_max values in LCT group than in MCT group. l-Lysine in Na⁺-independent transport was 10-fold lower in LCT group than in MCT group. The K_m values were not affected by feeding the LCT or MCT diet.
• 4.4. It is clear that amino acid transport is regulated by different types of dietary fat. We consider that the alteration of transport activity is attributable to the changes in number of membrane-bound transport carriers but not to their affinity.

     

Effects of Na+ and/or K+ on the Mg2+-dependent ATPase activities in shrimp (Macrobrachium amazonicum) gill homogenates

• 1.1. Homogenates of gills from the freshwater shrimp M. amazonicum exhibit the following ATPase activities: (i) a basal, Mg²⁺-dependent ATPase; (ii) an ouabain-sensitive, Na⁺ + K⁺-stimulated ATPase; (iii) an ouabain-insensitive, Na⁺-stimulated ATPase; and (iv) an ouabain-insensitive, K⁺-stimulated ATPase.
• 2.2. K⁺ suppresses the Na⁺-stimulated ATPase activity in a mixed-type kind of inhibition, whereas Na⁺ does not exert any noticeable effect on the K⁺-stimulated ATPase activity.
• 3.3. The Na⁺- and the K⁺-stimulated ATPase activities are totally inhibited by 5 mM ethacrynic acid in the incubation medium.
• 4.4. The Na⁺- and the K⁺-stimulated ATPase activities are not expressions of the activation of a Ca-ATPase.
• 5.5. The possible localization and roles of the described ATPases within the gill epithelium are briefly discussed and evaluated.

     

Sodium and potassium balance of captive meadow voles (Microtus pennsylvanicus) fed laboratory chow and vegetation diets

• 1.1. Mineral balance was studied in meadow voles (Microtus pennsylvanicus) maintained in the laboratory.
• 2.2. Urine and fecal Na⁺ contents of voles on low-Na⁺ diets were comparable to those reported for other herbivore species, but urine and fecal K levels were higher.
• 3.3. Voles approached Na⁺ balance (input = output) on diets with Na⁺ content as low as 56 ppm.
• 4.4. There was not a clearcut hypertrophy of the adrenal-gland zona glomerulosa in voles maintained on low-Na⁺ diets.
• 5.5. Plasma K content and bone water content were higher in voles maintained on high-Na ⁺ vegetation diets, suggesting expansion of extracellular fluid volume.

     

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.

     

Serum ions concentration and atpase activity in gills,kidney and oesophagus of european sea bass (Dicentrarchus labrax,pisces, perciformes) during acclimation trials to fresh water

• 1.1. Kidney, oesophagus and gill Na⁺-K⁺ ATPase activity and serum Na⁺, K⁺ and Cl⁻ concentrations are evaluated in European sea bass during experimental acclimation to fresh water.
• 2.2. Kidney and oesophagus ATPase increase in low salinity and reach a maximum in fresh water.
• 3.3. Gill ATPase decreases during the acclimation trials and rises again to normal values after a 3-week stay in fresh water.
• 4.4. Na⁺ and K⁺ serum concentrations decrease during the trials and increase back after a 3-week stay in fresh water.
• 5.5. The correlations between enzymatic activities, serum ion concentrations, morphological changes and environmental salinity are discussed.

     

Na+-K+ ATPase and carbonic anhydrase activities in larvae,postlarvae and adults of the shrimp Penaeus japonicus (Decapoda,Penaeidea)

• 1.1. Activities of Na⁺-K⁺ ATPase and carbonic anhydrase were measured through the early post-embryonic development of Penaeusjaponicus. In adults, only the Na⁺-K⁺ ATPase activity was measured.
• 2.2. ATPase activity was variable in the successive development stages. From zero in nauplii, the activity slightly increased in zoeae, and rose sharply in mysis stages 2 and 3.
• 3.3. A further significant increase in activity was noted at the transition from late mysis to early postlarvae, concomitant with a change from the larval osmoconforming pattern of osmoregulation to the postlarval and adult hyper-hyporegulating pattern.
• 4.4. The activity of Na⁺-K⁺ ATPase, measured in isolated cephalothorax, increased from PL3 to PL4 to its maximum value in PL5; at this stage, osmoregulatory capacity was fully efficient.
• 5.5. In young stages of P. japonicus, the variations in Na⁺-K⁺ ATPase activity appear correlated with the development of osmoregulatory ultrastructures, and with osmoregulation and salinity tolerance.
• 6.6. These results are discussed with regard to their ecological and physiological implications.
• 7.7. In adults, the activity of Na⁺-K⁺ ATPase was high in gills and epipodites and no activity was detected in branchiostegites. These results are related to the ultrastructure of these organs.
• 8.8. The activity of carbonic anhydrase did not change significantly in larval and postlarval stages.
• 9.9. From these results, it is proposed that the effector sites of osmoregulation are located in branchiostegites, pleurae and epipodites in postlarvae, and in epipodites and mainly in gills in adults.

     

Comparative study of the endemic freshwater fauna of lake baikal—I. Phospholipid and fatty acid composition of two mollusc species,Baicalia oviformus and Benedictia baicalensis

• 1.1. Lipid and phospholipid compositions of endemic freshwater molluscs belonging to the class Gastropoda, Baicalia oviformus and Benedictia baicalensis, were studied.
• 2.2. The fatty acids composition of total lipids, neutral, glyco- and phospholipid fraction was investigated by capillary gas chromatography-mass spectrometry.
• 3.3. Ninety-five fatty acids were identified: 23 saturated (both iso- and anteiso-), 28 monoenoic, 14 dienoic and 30 polyenoic.
• 4.4. High percentage of the two main acids, 18:4 and 18:4(n-3) in phospholipid and glycolipid fractions were identified.
• 5.5. A number of unusual polyunsaturated fatty acids, such as 19:4, 18:5(n-3), 24:4(n-6), 24:5(n-6), 24:6(n-3), and furanoid acids, were found.

     

Interaction with functional membrane proteins—A common mechanism of toxicity for lipophilic environmental chemicals?

• 1.1. The effects of several phenols, anilines and aliphatic alcohols on yeast plasma membrane H⁺-ATPase and purine transport system as well as on Na⁺, K⁺-ATPase and adenosine uptake by Chinese hamster ovary cells (CHO) were investigated.
• 2.2. In all cases an inhibition was observed, which could be correlated with the octanol/water partition coefficients of the substances tested, thus making quantitative structure-activity predictions possible.
• 3.3. The observed effects correlated well with the influence of the chemicals on cell growth.
• 4.4. The results suggest a common mechanism of toxicity by the action of hydrophobic xenobiotics on biomembranes.

     

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.

     

Intestinal l-methionine transport in the cultured gilthead bream (Sparus aurata)

• 1.1. The influx and transepithelial movements of l-methionine and its effects on the electrophysiology and Na-Cl-transport in upper and lower intestine of the cultured fish, Spanis aurata, were measured.
• 2.2. The K_m and V_max of l-methionine influx into the tissues were higher in lower intestine than in upper intestine. A prominent diffusion-like transport component was also measured in both segments during influx experiments.
• 3.3. Net transepithelial fluxes of l-methionine (1 mM) were observed in both upper and lower intestine, this transport being Na⁺-dependent.
• 4.4. The two intestinal segments exhibited an electrical potential difference (PD) and a short circuit current (I_sc) serosa negative or near zero. Tissue conductance (G_t) was higher in posterior than in lower intestine.
• 5.5. Addition of l-methionine to the mucosal side of lower or upper intestine did not induce changes in PD in either part.
• 6.6. Isotopic fluxes of Cl⁻ or Na⁺ measurements under short circuit conditions showed that there were no net Cl⁻ or Na⁺ transport in either part.
• 7.7. l-Methionine additions to the mucosa did not induce changes in unidirectional fluxes of Cl⁻ or Na⁺ or in the (I_sc) in either the anterior or posterior intestine.

     

Changes in size,hydration and low molecular weight osmotic effectors during meiotic maturation of Fundulus oocytes in vivo

• 1.1. Gains in the water content of the Fundulus heteroclitus follicle account for over 90% of the total wet weight increase, and consequentially most of the size increase, associated with meiotic maturation.
• 2.2. Increases in intracellular Na⁺ and K⁺ actually exceed the accompanying increases in oocyte water, resulting in net gains in the concentration of these solutes. Changes in oocyte osmolality during maturation are mostly closely paralleled by variations in the concentration of K⁺.
• 3.3. Concentrations of various free amino acids, including taurine, remain constant or decline during maturation.
• 4.4. Taken together, these results suggest that an influx of K⁺, followed by osmotically-obliged water, is a primary cause of water uptake during oocyte maturation in F. heteroclitus.

     

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.

     

Dietary linoleic acid affects phospholipid fatty acid composition in heart and eicosanoid production by cardiomyocytes from atlantic salmon (Salmo salar)

• 1.1. Atlantic salmon post-smolts were fed practical-type diets containing linoleic acid at 10, 25 or 45% of total dietary fatty acids for a period of 20 weeks.
• 2.2. As dietary linoleic acid was increased, individual phospholipids of heart contained increased levels of 18:2n-6, 20:2n-6, 20:3n-6 and 20:4n-6 and reduced levels of 20:5n-3. The ratio of n-3/n-6 polyunsaturated fatty acids in heart phospholipids decreased and the ratio of 20:4n-6/20:5n-3 increased.
• 3.3. An increased production of thromboxane B₂ occurred in isolated cardiac myocytes from fish given the highest dietary linoleic acid but the production of 6-keto prostaglandin F_1α was not significantly affected, nor was the activity of heart sarcoplasmic reticulum Ca²⁺-Mg²⁺ ATPase (EC 3.6.1.4).