Nutritional regulation of glycolysis in rainbow trout (Salmo gairdneri R.)

1. Some physico-chemical constants and the nutritional regulation of pyruvate kinase (PK), phosphofructokinase (PFK) and hexokinase (HK) from rainbow trout liver was investigated. 2. The maximum activity pH for the three enzymes appears to be in a physiological range. 3. The PK-enzyme shows sigmoid kinetic with respect to PEP with a Hill-coefficient of 3.1; the other two enzymes show michaelian kinetic for their substrates. 4. The nutritional treatments show that HK-enzyme increases its level with high carbohydrate diet and decreases with high protein diet and starvation. 5. PFK-enzyme decreases with high protein diet and starvation. 6. PK-enzyme only shows a decrease in level with starvation conditions.     

Phosphofructokinase during haemopoiesis of the rainbow trout (Salmo gairdneri R.): its isoenzymatic forms

Phosphofructokinase (EC 2.7.1.11) from trout haemopoietic cells and erythrocytes exhibits biphasic behaviour, with respect to fructose 6-phosphate and MgATP in extracts filtered through Sephadex G-25. Two different values of Hill coefficient and S0.5 have been found for each cellular population. Two forms of the enzyme with high and low affinity for the substrates, were obtained after affinity chromatography in each cellular population. The kinetic behaviour of these forms is different and may be due to a distinct composition and/or proportion and contribution of phosphofructokinase isoenzymes in both types of cells.     

The rainbow trout Salmo gairdneri (Rich.) fishery of Lake Titicaca

Rainbow trout were introduced to Lake Titicaca in 1942. A commercial trout canning operation started in 1961 but terminated in 1970. Data for this study were collected in 1966 and 1967, with the object of examining the life history, biology, and commercial fishery of Titicaca rainbow trout. Trout were caught commercially and experimentally by gillnets in different parts of the lake.
Lake Titicaca lies across the border of Peru and Bolivia at 3212 m above sea level. The physico-chemical characteristics of the lake appear ideal for self-sustaining populations of rainbow trout. Growth was constant throughout the year, and was good in relation to growth rates of rainbow trout in other parts of the world. Spawning took place in the tributaries in the winter. Recruitment to the fishery occurs in 7.62 cm stretch mesh gillnets at about 27 cm fork length.
The total annual commercial catch increased to 500 metric tons in 1965 before subsequently decreasing. The simplest explanation for the decline in total catch would be the increase in fishing mortality due to increased fishing effort, although it is possible that the decline in water level has had some effect. It appeared possible that the lake could sustain an annual catch of about 350 tons.     

Spermiogenesis in the rainbow trout (Salmo gairdneri)

In an ultrastructural study on the spermiogenesis of the rainbow trout (Salmo gairdneri R.) four spermatogenetic stages were identified. In young round spermatids, the nuclear chromatin was first heterogeneous (euchromatin and heterochromatin). Subsequently, it became more homogeneous and started to condense in the form of coarse granules and fibers and then into fibrils associated in ribbon-like elements which eventually partly fused together. During early spermiogenesis, a juxtanuclear vacuole appeared in the area where the nuclear envelope was specialized due to condensation of material between the two envelopes and a slight accumulation of nuclear material. This area was finally located in the anterior part of spermatids and spermatozoa; it probably plays a role during fertilization. A flagellar rootlet appeared early in spermiogenesis; it may play a role in the attachment of the flagellum to the nucleus since it persisted until the centriolar complex was definitively fixed in the implantation fossa. The flagellum did not display a plasma membrane and was first located in the cytoplasm, but when it was later extruded from the cell, it acquired a membrane. The cytoplasm was rich in ribosomes (free or in small groups) but poor in membranous organelles. The few mitochondria polarized around the centriolar complex were finally organized into an annular mid-piece. The spermatids remained connected by intercellular bridges until the end of spermiogenesis. The complexity of trout spermiogenesis is intermediate between that in poecilids and that in carp and pike, which have very simple spermatozoa. The role of the material from the nucleus and the cytoplasm reaching the Sertoli cell in the control of spermatogenesis has been discussed.     

Erythroid 5-aminolevulinate synthetase from trout (Salmo gairdneri R.)

A mitochondrial and cytosolic erythroid ALA-synthetase have been found in trout. The polypeptide existent in the cytosol is probably a precursor of the 90,000 mol. wt mitochondrial ALA-synthetase. The erythroid ALA-synthetase is about 20,000 mol. wt larger than the hepatic enzyme. The differences in mol. wt and catalytic properties between erythroid and hepatic enzyme support the existence of two forms of the ALA-synthetase in teleostei.     

Lysosomal damage under nitrite intoxication in rainbow trout (Salmo gairdneri Rich.)

1. In Salmo gairdneri specimens exposed to 450 micrograms/l NO2-N (nearly 36 hr LC50) for various exposure times (12-72 hr) some parameters of liver lysosomal function were examined. 2. In vivo both total proteolytic activity and single protease activities were inhibited, the inhibition increasing with the lengthening of exposure time. In vitro no analogous effect was observed. 3. Lysosomal membranes showed an increased fragility correlated with the physiological conditions of treated animals. 4. Data were considered as the results of a nitrite mediated effect on functional and structural proteins.     

Apomorphine-induced vomiting in rainbow trout (Salmo gairdneri)

1. The LD50 for a 7-day period following intraperitoneal injection of apomorphine-HCl was calculated to be 158 mg/kg in rainbow trout. 2. Intraperitoneal injection of apomorphine at doses of 60 mg/kg or greater caused vomiting of plastic balls which had been placed in the stomachs of rainbow trout. 3. Apomorphine-induced effects included vomiting, vomiting behavior, toxicity, increased respiration, impaired motor control and equilibrium, and increased aggression. 4. The vomiting control mechanism of trout may be similar to that described in mammals.     

Cytochemical demonstration of acid phosphatase activity in the pineal organ of the rainbow trout,Salmo gairdneri

Summary Activity of acid phosphatase (ACP) was investigated cytochemically in the pineal organ of the rainbow trout, Salmo gairdneri. Intense reaction product for ACP activity was observed (1) in lysosomes varying in size and shape and (2) in endoplasmic reticulum associated with the Golgi complex of (i) the pineal photoreceptor and supporting cells, (ii) vascular endothelial cells, and (iii) macrophages inhabiting pineal lumen, parenchymal epithelium and perivascular spaces. This localization of ACP is discussed with particular reference to the capacity for lysosomal digestion in a pineal organ combining photoreceptive and secretory functions, and lacking a blood-brain barrier, as holds true for the pineal of the rainbow trout. Taking advantage of its capacity for endocytotic uptake and lysosomal digestion, the pineal organ of the rainbow trout may serve as a barrier between the blood circulation and the cerebrospinal-fluid compartment. Furthermore, the macrophages may be considered as an essential component in pineal function of fish.Fellow of the Alexander von Humboldt Foundation.Fellow of the Alexander von Humboldt Foundation.     

Temporal variations in the diet of brown trout (Salmo trutta L.) and rainbow trout (S. gairdneri R.) in Rutland Water

The diet of brown trout (Salmo trutta L.) and rainbow trout (S. gairdneri Richardson) in Rutland Water were compared during the first two fishing seasons (April–October 1977 and 1978).Fortnightly samples of approximately forty stomachs were obtained from boat and bank, rod-and-line caught trout giving a total of 1046 stomachs over the two seasons.During 1977 seasonal changes in the diet were divided into two phases; the first being a period of abundant drowned terrestrial food until June. This was followed by a period of more stable water level from July onwards when chironomid larvae and pupae were consistently the most important food items and the diversity of food also increased.In 1978 the proportion of chironomid pupae and larvae declined and they were replaced in the diet by Gammarus and Asellus.     

The glutathione S-transferase activity in the kidney of rainbow trout (Salmo gairdneri)

Trout kidney contains 2.3 mmol GSH/kg. The cytosolic glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene as substrate is 0.35 mumol/min/mg protein. There is no detectable activity with 1,2-epoxy-3-(p-nitrophenoxy)propane, ethacrynic acid, p-nitrobenzyl chloride or p-nitrophenyl acetate. A variable proportion of the activity does not bind to a glutathione-affinity matrix. Its Km values for GSH and 1-chloro-2,4-dinitrobenzene are 3.0 and 5.1 mM, respectively. The rest of the activity is eluted from the affinity matrix as one main and two minor peaks. The main peak has Km values for GSH and 1-chloro-2,4-dinitrobenzene of 0.4 and 4.5 mM, respectively. Its subunit Mr is 22,900. The activity in the main peak is inhibited progressively by 1-chloro-2,4-dinitrobenzene with a rate constant of 0.11/min.     

Crystallization of the rainbow trout (Salmo gairdneri) haemoglobin IV

Crystals of rainbow trout (Salmo gairdneri) haemoglobin IV were grown in mini batches from a solution of ammonium sulphate. Large single crystals grew over five days and were up to 2 mm in length. X-ray diffraction experiments indicated a space group of C222(1) with unit cell dimensions of a = 85.3 A, b = 94.6 A and c = 105.7 A. The crystals diffract to better than 2.5 A but exhibit some mosaicity along the c axis.     

In vitro mitogenesis of peripheral blood lymphocytes from rainbow trout (Salmo gairdneri)

1. In vitro mitogenesis of rainbow trout peripheral blood lymphocytes (RBT PBL) was investigated to assess the applicability of this procedure in assessment of fish health. The assay variables of media, mitogen type and concentration, serum supplementation, lymphocyte isolation procedure, and duration of incubation were assessed. 2. Concanavalin A (Con A) stimulated greater proliferation of RBT PBL than did lipopolysaccharide (LPS), phytohemagglutinin (PHA), or pokeweed mitogen (PWM). 3. RBT PBL, cultured with 10 micrograms Con A/ml and incubated for four or five days, exhibited greater proliferation than with other treatment combinations. 4. The degree of Con A-induced PBL proliferation varied significantly (P less than 0.05) among fish. The mean was positively correlated with the relative standard deviation and thus exhibited significant heteroscedasticity. 5. Human serum, as an alternative to FBS supplementation of the culture medium, did not enhance RBT PBL proliferation or reduce variation in mean proliferation. 6. Power analysis with variance estimates from this study reveal that sample size requirements of further studies under the given conditions could severely limit the applicability of this procedure for RBT health assessment. Further work in this area should center around standardization of culture conditions pertaining to the source of protein supplementation.     

Chromosome polymorphism in the rainbow trout (Salmo gairdneri Richardson)

Chromosome preparations from lymphocyte cultures of 50 rainbow trout were studied. Diploid chromosome numbers of 59, 60, 61, 62 and 63 were found in different individuals in which the arm number (NF) was 104. Intraindividual polymorphism was found at a low level in 25 of the fish. The results suggest that numerous chromosome polymorphisms exist in rainbow trout.     

The response of alkaline phosphatase to osmoregulatory changes in the trout,Salmo gairdneri

Summary The relationship between alkaline phosphatase and environmental salinity was examined in the rainbow trout and the migratory rainbow (steelhead),Salmo gairdneri. The enzyme activity in tissues involved in osmoregulation was strongly correlated with the adaptation salinity and thus to the degree of salt and fluid transport in those tissues. After transfer from freshwater to seawater, the specific activity of the enzyme increased over 260% in the intestine, decreased by 50% in kidney, and was unchanged in the liver, an organ not directly involved in osmoregulation. The sea-run steelhead trout response was similar to the nonmigratory rainbow; although, the pre-migratory transformation (smoltification) had no effect on enzyme activity. Amino acid inhibitors of alkaline phosphatase significantly reduced fluid absorption in the isolated intestine of rainbow trout, reaffirming the relationship between the enzyme and fluid movement. Electrophoretic identification of trout alkaline phosphatase isozymes, clearly distinguishes the enzyme from different tissue origins. However, from the analysis of intestinal electrophoretic patterns, osmoregulatory adjustments are not associated with the induction of new alkaline phosphatase isozymes, or in the large scale preferential stimulation of one of the two existing intestinal isozymes over the other.     

Organ distribution of aldehyde dehydrogenase activity in the rainbow trout (Salmo gairdneri Richardson)

1. Aldehyde dehydrogenase activity was measured in gills, muscle, brain, intestine, kidney, heart and liver of rainbow trout, using 3,4-dihydroxyphenylacetaldehyde (the biogenic aldehyde derived from dopamine) as the substrate. 2. Aldehyde dehydrogenase activity was found to be present in all of the organs studied. 3. The highest activity was found in the liver (276 nmol/min.g wet wt of tissue). 4. A remarkably high activity was found in the heart (117 nmol/min.g). 5. The gills showed the lowest activity (1.9 nmol/min.g).     

Characterization of the muscarinic and serotoninergic receptors of the intestine of the rainbow trout (Salmo gairdneri)

The ability of carbachol and 5-hydroxytryptamine (5-HT) to contract isolated segments of rainbow trout intestine in a concentration-dependent manner indicates the presence of muscarinic and serotoninergic receptors in this tissue. The activity of these agonists appears to be directly on the smooth muscle, since ganglionic blockers and inhibitors of neurotransmission did not inhibit contractions. The carbachol-induced contractions were selectively inhibited by atropine and (+-)-3-quinuclidinyl xanthene-9-carboxylate hemioxalate hydrate, an M-2 muscarinic receptor antagonist. However, the inhibition was not competitive. McN-A-343, an M-1 muscarinic agonist had no effect on intrinsic tone. The 5-HT-induced contractions were selectively inhibited by methysergide and the 5-HT2 receptor blockers, ketanserin and 1-(1-naphthyl)piperazine. Again, the inhibition by these agents was not competitive. 5-HT1 and 5-HT3 receptor antagonists did not inhibit contractions. The results thus suggest that the smooth muscle of the rainbow trout intestine contains M-2 muscarinic and 5-HT2 receptors.     

Ultrastructure of the physostomatous swimbladder of rainbow trout (Salmo gairdneri)

Summary Rainbow trout swimbladder epithelium consists of non-ciliated and ciliated cells in the ratio of greater than 21. Non-ciliated cells contain vesicles filled with a mucus-like material and similar material is found lining the surface of the swimbladder lumen. Morphological evidence for discharge of the vesicle contents was obtained. In addition, nonciliated cells contain osmiophilic lamellar bodies which resemble the cytosomes of lung alveolar cells of air-breathing vertebrates. The non-ciliated cells do not appear to be involved in a process of active gas secretion.Supported by a research grant from the American Cancer Society, Oregon Division, Inc.