Effect of salinity on the osmotic,chloride, total protein and calcium concentrations in the hemolymph of the prawn Peneaus monodon (fabricius)

• 1.1. Osmolality and chloride concentrations in the hemolymph of Penaeus monodon became stable 1 day after molting in 32 ppt, while total protein and calcium concentrations remained stable throughout the molting cycle. When intermolt (≥ 36 hr postmolt) animals were transferred from control (32 ppt) to experimental (8–40 ppt) salinities, osmolality, chloride and total protein, but not calcium, concentrations in the hemolymph achieved steady state values 24–48 hr after transfer.
• 2.2. The hemolymph osmolality was a linear function (slope = 0.28) of medium osmolality at salinities between 8 and 40 ppt. It was isosmotic to seawater at 698 mOsm (10 g prawns) and 752 mOsm (30 g), and was hyperosmotic to the medium below isosmotic concentrations, and hypoosmotic to those above.
• 3.3. Hemolymph chloride concentration was isoionic to seawater at 334 mM, and was hyperregulated below isoionic concentrations, and hyporegulated to those above.
• 4.4. P. monodon maintained its hemolymph calcium concentration between 6.4 and 10 mM when medium salinities increased from 8 to 40 ppt.
• 5.5. Total protein concentration in the hemolymph was independent of medium salinity (8–40 ppt) and hemolymph osmolality (540–850 mOsm).

     

Ontogenic change of digestive enzymes in Penaeus monodon

• 1.1. Ontogenic changes of both proteases and carbohydrases of Penaeus monodon from different larva stages to adult were investigated.
• 2.2. Total protease activity was low during nauplius and zoea but peaked up in mysis. This was due to the activity increase of both trypsin and chymotrypsin.
• 3.3. The change of isozyme pattern of these two enzymes from different life stages of the shrimp was further determined by functional staining on an electrophoregram.
• 4.4. Activity of α-amylase increased after the post-larva stage, while that of chitinase and maltase showed a peak in zoea then gradually decreased to adult.
• 5.5. The ratio of α-amylase activity to protease coincided with the dietary change of the shrimp in different life stage.

     

Changes in blood metabolite concentrations in response to repeated capture,anaesthesia and blood sampling in the golden perch,Macquaria ambigua

• 1.1. The major metabolic changes associated with repeated capture, aquarium transfer, anaesthesia and blood sampling were investigated in an Australian freshwater fish, the golden perch (Macquaria ambigua),
• 2.2. A compounded stress response was seen after repetition of the procedure, in which the plasma glucose rose within 3 hr and amino acid concentrations rose and the serum free fatty acids concentration fell after 24 hr.
• 3.3. Alanine was identified as an important circulating energy store in the stress response of golden perch.
• 4.4. No change was noted in the serum protein, plasma lactate or β-hydroxybutyrate concentrations, indicating that tissue damage and hypoxia were absent, and that degradation of free fatty acids did not produce metabolites excess to the requirements of gluconeogenesis and the tricarboxylic acid cycle.

     

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.

     

Time-dependent cadmium-neurotoxicity in rat brain synaptosomal plasma membranes

• 1.1. The modulation of lipid dynamics and lipid protein interactions were studied in rat brain synaptosomal plasma membranes (SPM) up to 24 hr after exposure to cadmium (Cd).
• 2.2. The activity of acetylcholinesterase and adenylate cyclase showed a considerable decrease after 6 hr of Cd exposure, followed by a progressive increase up to 24 hr.
• 3.3. SPM chemiluminescence showed a maximum decrease at 12 hr, demonstrating a considerable increase in lipid peroxidation.
• 4.4. SPM of Cd-exposed animals showed a statistical significant increase in fluorescence anisotropy parameter [(r₀/r) — 1]⁻¹ at 18 and 24 hr compared to SPM of the control, indicating a decrease of membrane fluidity.

     

Sublethal effects of hypoxia in the abalone (Haliotis rufescens) as measured by in vivo31P NMR spectroscopy

• 1.1. Effects of hypoxia were investigated in red abalones (Haliotis rufescens) using a flow-through exposure system and in vivo³¹P NMR spectroscopy.
• 2.2. Following seawater acclimation, abalones were exposed to air for 1 hr, then seawater for 2.5 hr to check recovery; parallel controls were performed without air exposure.
• 3.3. In foot muscle, hypoxia produced a decrease in phosphoarginine concentration and intracellular pH, an increase in inorganic monophosphate concentration, and no change in that of ATP; upon resubmergence, all effects generally recovered.
• 4.4. The changes induced by hypoxia during normal tidal changes are consistent with the blockage of mitochondrial oxidative phosphorylation.
• 5.5. Use of in vivo NMR allows measurement of the biochemical effects of natural stress factors in live, intact aquatic organisms in the laboratory.

     

The effect of time on physiological changes in eel Anguilla anguilla,induced by lindane

• 1.1. Eel were exposed to a sublethal concentration of lindane (0.335 ppm) for 6, 12, 24, 48, 72 and 96 hr.
• 2.2. Concentrations of glycogen, glucose, lactate, pyruvate and lipids were determined in gill tissue after lindane exposure.
• 3.3. Gill glycogen descreased and glucose levels increased at 6 hr of treatment, lactate and pyruvate concentration increased between 6 and 48 hr. Total lipid values decreased between 6 and 24 hr; thereafter, the levels increased up to 72 hr of exposure.
• 4.4. Clear changes were found in all parameters tested in gill tissues. The observed effects of lindane on metabolism in fish are discussed in relation to acute stress syndrome.

     

Adenylate energy charge: A possible trophic index for management of oyster intensive aquaculture

• 1.1. O. edulis and C. gigas both exhibit a seasonal variation in AEC with minimum values in summer. Two factors, food and temperature, were examined to explain these low summer values.
• 2.2. The AEC level varied with food level but a seasonal pattern was still observed. Two age groups of oysters were tested, giving a similar response.
• 3.3. The effect of temperature on the seasonal variations in AEC was confirmed by a significant correlation between AEC and temperature. This relationship allows us to calculate an AEC standard that only retains the trophic information.
• 4.4. Different trophic levels were identified in Marennes-Oléron Bay with AEC standard but growth rate was not related to them. So, AEC may inform on the carrying capacity of a given area but does not predict growth performances which will depend on other parameters.

     

Digestion of protein in different marine species

• 1.1. The digestion proteases in five marine species (Atlantic halibut, Hippoglossus hippoglossus (L); Dover sole, Solea solea (L); turbot, Scophthalmus maximus, (L); European lobster, Hommarus gammaarus (L); and the giant prawn, Penaeus monodon) have been compared by biochemical methods.
• 2.2. The pH profiles for the hydrolysis of casein by extracts from the digestive systems of each species showed different characteristics; extracts from adult halibut, turbot and sole exhibited strong pepsin-like activity; whereas this enzyme was absent in P. monodon and in sole larvae.
• 3.3. Although lobster extracts, from either the hepatopancreas or the stomach, showed peaks at pH values of 5.8 and 2.5, this latter activity did not hydrolyse a specific substrate for pepsin.
• 4.4. Halibut and turbot digestive extracts contained an activity optimal at pH values in the region of 5.0 resembling a cathepsin-like enzyme; an activity which was not evident in the other species under similar experimental conditions.
• 5.5. Although all species possessed trypsin-like activity, the pH profiles of activity in the neutral to alkaline region were unique to each species.
• 6.6. The significance of these results is considered with respect to the anatomical differences in the alimentary systems of these species.

     

Increased muscle glucose uptake in response to chronic glyburide treatment is not related to changes in glucose transporter (GLUT4) protein

• 1.1. The mechanism of action of glyburide (a sulfonylurea) on muscle has been investigated by measuring glucose uptake and glucose transporter (GLUT4) protein levels after chronic glyburide treatment.
• 2.2. A dietary induced insulin resistant rat model (4 wk of high-fat, high-sucrose feeding) was given glyburide (2mg/kg/day) for 10 days and glucose uptake was measured in a perfused hindquarter preparation.
• 3.3. Protein levels of the GLUT4 glucose transporter were determined by Western analysis.
• 4.4. After 7 days of treatment, rats fed glyburide had lower blood glucose concentrations 2 hr (72 ± 5 vs 103 ± 12 mg/dl) and 24 hr (97 ± 7 vs 123 ± 7 mg/dl) after glyburide administration with no difference in serum insulin levels compared to vehicle treated animals.
• 5.5. Glucose uptake was approx doubled in basal state (0 insulin) in response to glyburide (2.8 + 0.4 vs 1.7 ± 0.2μ mol/g per hr).
• 6.6. Maximal insulin (100 nM) stimulated glucose uptake tended to be higher in the glyburide treated group, but did not reach statistical significance (8.0 ± 0.7 vs 7.0 ± 0.6 μmol/g per hr).
• 7.7. Western analysis revealed no significant effect of glyburide on the GLUT4 protein level in skeletal muscle.
• 8.8. These results suggest that glyburide alters glucose uptake through some mechanism other than alterations in the level of the GLUT4 glucose transporter protein.

     

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.

     

Sex-specific gene expression in distinct tissues of the shrimp Penaeus vannamei

• 1.1. Soluble proteins extracted from male and female Penaeus vannamei tissues such as eyes, eyestalks, brain, nerve cord, hemolymph, heart, muscle, hepatopancreas, hepatopancreas membrane and cuticular epidermis were analyzed and compared by high-resolution mini-two-dimensional polyacrylamide gel electrophoresis (mini-2D-PAGE).
• 2.2. In each shrimp tissue a large number of discrete polypeptides was observed.
• 3.3. The polypeptide patterns from the same tissue of female and male shrimp were mostly similar but both qualitative and quantitative differences were noted, suggesting the presence of sex-specific gene products in various shrimp tissues.
• 4.4. Future applications of these results are discussed.

     

The relationship between osmoregulation and nitrogen metabolism in the intertidal prawn,Palaemon elegans (Rathke)

• 1.1. The relationship between nitrogen metabolism and osmoregulation has been studied in the prawn Palaemon elegans (Rathke) following sudden exposure to hyper- and hyposaline conditions.
• 2.2. Animals acclimated to a salinity of 30‰ showed a pronounced increase in the rates of ammonia excretion during the first 2 hr after transfer to lower salinities. These gradually declined during the next 6 hr to rates that were significantly higher than that of control animals (30‰) and were maintained throughout the rest of the experiment.
• 3.3. Rates of ammonia excretion in animals transferred to hypersaline conditions (40‰) fluctuated considerably during the experiment. It was consistently observed, however, that there were two periods during the experiments when ammonia excretion rates had negative values indicating that NH⁺₄ ions were being taken up by the prawns.
• 4.4. Experiments in which small quantities of (NH₄)₂SO₄ containing the stable isotope ¹⁵N were added to the sea-water confirmed that P. elegans was able to take NH⁺₄ ions from the sea-water.
• 5.5. Changes in the Na⁺ ion concentration in the blood and the changes in free amino acid concentration in the blood and in the muscle after exposure to differing salinities were also determined. Their significance and relationship to the observed changes in the rates of ammonia excretion are discussed.

     

Effect of temperature and salinity on the oxygen consumption of laboratory produced Penaeus californiensis postlarvae

• 1.1. The oxygen consumption by P. californiensis postlarvae (mean wt = 0.38 g) was determined at five different temperatures and four salinities.
• 2.2. The O₂ in each chamber was recorded at 10 min intervals for 1 hr. The time course of oxygen depletion was independent of O₂ concentration down to 1.6 mg/l.
• 3.3. Oxygen consumption increased with temperature from 0.0045 mg/g/min at 19°C, to 0.0142 mg/g/min at 35°C. The thermal coefficient (Q₁₀) indicated a very high sensitivity of the postlarvae to temperature variations at 19–23°C.
• 4.4. The results show that oxygen consumption significantly depends on temperature (P < 0.001) while salinity has only a marginal effect.

     

Comparison of the proliferation and differentiation of myogenic satellite cells and embryonic myoblasts derived from the turkey

• 1.1. Embryonic and posthatch turkey skeletal muscle development was compared in in vitro studies using clonal-derived embryonic myoblasts and satellite cells.
• 2.2. Although population doubling times were similar between the two lines (25.4 hr for satellite cells and 26.4 hr for embryonic myoblasts), embryonic myoblasts consistently began log phase growth 24 hr earlier than satellite cells.
• 3.3. Differentiation (fusion) of embryonic myoblasts was maximized by 36 hr in Dulbecco's Modified Eagle's Medium containing 1% horse serum compared with 72 hr for satellite cells.
• 4.4. When administered a serum-free medium which supports proliferation of turkey satellite cells, embryonic myoblasts differentiated to form myotubes.

     

Effect of diet and essential amino acids gavage on young rat amino acid metabolism enzymes

• 1.1. The effects of a high-fat, high-energy diet and essential plus semi-essential amino acid gavage on pup rats have been studied (60–65 animals).
• 2.2. The activities of alanine transaminase, adenylate deaminase, glutamine synthetase and serine dehydratase have been tested in liver and muscle.
• 3.3. Plasma was used for the estimation of proteins, urea, amino acids, glucose, lactate, 3-hydroxy-butyrate and acetoacetate.
• 4.4. Liver and muscle glutamine synthetase activities are increased by diet and gavage administered. Hepatic serine dehydratase is inhibited by a cafeteria diet but activated by amino acid gavage. Adenylate deaminase is inhibited by diet and gavage in the liver, but gavage does not affect this enzyme activity in muscle. Liver alanine transaminase is increased by the diet; in the muscle, cafeteria diet and amino acid gavage showed the highest values for this enzyme.
• 5.5. In the plasma, the increase in lactate produced by the diet is inhibited by the amino acids provided. Cafeteria-fed pups showed lower urea levels and higher 3-hydroxybutyrate concentrations in the plasma.
• 6.6. Intracellular glucose is diminished by cafeteria diet. In contrast, the blood cell amino acid concentration increases with diet and gavage supplied.

     

Effects of anoxia on the haemolymph physiology and lactate concentrations in the freshwater crab Potamon warreni calman

• 1.1. Haemolymph lactate levels rose rapidly from 0.54 ( ± 0.39) mmol to 34.78 ( ± 4.9) mmol during 6 hr of anoxia in a N₂ atmosphere.
• 2.2. A sharp decrease in the pH from 7.478 (± 0.04) to 7.197 ( ± 0.04) and the total carbon dioxide content of the haemolymph from 13.97 (± 2.0) mmol to 6.25 (± 1.2) mmol during anoxia indicates a gross disturbance in the acid-base balance in Potamon warreni.
• 3.3. The low concentrations of succinate (98 ± 30 μmol) and alanine (5.8 ± 1.0 mmol) in the haemolymph suggest that they do not play a role as an energy source during anoxia.
• 4.4. Probably only l-( + )-lactate is produced during lactate production when P. warreni is exposed to anoxic conditions.

     

Varying amounts of stretch stimulus regulate stretch-induced muscle hypertrophy in the chicken

• 1.1. The effects of different amounts of passive stretch per day and number of days of stretch on muscle hypertrophy in the chicken patagialis (PAT) muscle were determined.
• 2.2. Stretch for 24 hr per day (h/d) resulted in a more rapid hypertrophy both on a wet and dry tissue basis (P < 0.001) than stretch for 4 h/d.
• 3.3. Stretch increased PAT weight 43% and 25% in 24 h/d and 4 h/d treatments, respectively, after 10 days of stretch, but by day 25 of stretch there was no difference between treatments.
• 4.4. In a second experiment, the PAT muscle was hypertrophied and then the effects of intermittent stretch (4 h/d) on regression of hypertrophy (muscle atrophy) were investigated.
• 5.5. Intermittent stretch (4 h/d) for 5 and 10 d significantly (P < 0.001) inhibited regression of hypertrophied muscle.
• 6.6. The results of the present study indicate that stretch-induced hypertrophy can be modulated by varying the amount of stretch applied per day.
• 7.7. Intermittent stretch can be used to inhibit the regression which occurs when a continuous stretch stimulus is removed.
• 8.8. Intermittent stretch is a useful model for investigating mechanisms of muscle hypertrophy and inhibition of muscle atrophy.

     

Reduced muscle protein breakdown in septic rats following treatment with interleukin-1 receptor antagonist

• 1.1. The role ofinterleukin-1 (IL-1) in sepsis-induced muscle proteolysis was assessed by treating septic rats with recombinant IL-1 receptor antagonist (rIL-Ira).
• 2.2. In initial experiments, we tested the effectiveness of IL-Ira in preventing muscle proteolysis induced by administration of IL-1.
• 3.3. When normal rats were treated with rIL-α (three intraperitoneal doses of 100 μ g/kg body weight each over 16 hr), total and myofibrillar muscle protein breakdown rates, measured as release oftyrosine and 3-methylhistidine, respectively, by incubated extensor digitorum longus muscles, were significantly increased.
• 4.4. This metabolic response to IL-α was completely abolished by rIL-Ira, administered as three intraperitoneal doses of 3 mg/kg body weight each over 16hr.
• 5.5. In subsequent experiments, sepsis was induced in rats by cecal ligation and puncture (CLP); non-septic rats were sham-operated.
• 6.6. Treatment of septic rats over 16hr with a total dose of 25mg/kg body weight of rIL-Ira reduced, but did not normalize, the increased muscle protein breakdown rates seen during sepsis.
• 7.7. When the dose of rIL-Ira was more than doubled and given as a constant infusion at a rate of 4.2 mg/kg body weight/hr for 16 hr, the increased rate of muscle proteolysis in septic rats was normalized.
• 8.8. The present study offers the first direct evidence that IL-1 is involved in the regulation of muscle proteolysis during sepsis.

     

1H NMR study of metabolic alterations in the small intestine of rats infected with Hymenolepis diminuta

• 1.1. 1H NMR spectra of the duodenum, jejunum and ileum tissues of the small intestine of a rat showed metabolic gradients.
• 2.2. The concentrations of metabolites in these gut regions were altered by the presence of the tapeworm Hymenolepis diminuta.
• 3.3. In the infected duodenum there was significantly less glycogen, glucose and phosphocreatine/creatine, but significantly more lactate than in the corresponding controls.
• 4.4. Infected jejunum contained significantly less betaine but significantly more succinate, alanine and lactate.
• 5.5. Infected ileum had significantly less glycogen and taurine but significantly more alanine and lactate.