Influence of dietary amino acid patterns on the free amino acid contents of blood and muscle of rainbow trout (Salmo gairdnerii R.).

1. Groups of rainbow trout were given one or other of two diets that differed in amino acid profile for two months; concentrations of free amino acids in whole blood and latero-dorsal muscle were then measured. The effects of temperature (12 and 18 degrees C in freshwater) and salinity on the concentrations of free amino acids in these tissues were also observed. 2. Although both diets apparently met the essential amino acid requirements of the trout and were isoenergetic, they nevertheless had different nutritional values for trout. 3. Patterns of free amino acids in tissues of trout given the two diets were different. Blood and muscle amino acid fractions were affected differently by changes in dietary amino acids.     

Branched chain alpha-keto acid dehydrogenase in tissues from rainbow trout (Salmo gairdnerii)

Mitochondria isolated from skeletal red muscle of rainbow trout (Salmo gairdnerii) have remarkably high activity of branched chain alpha-keto acid dehydrogenase as measured with alpha-keto isocaproic acid as substrate. The activity of the dehydrogenase increases several-fold after preincubation of the mitochondria with an uncouple and oligomycin. The accumulation of the first product, isovaleryl-CoA is strongly stimulated by high concentrations of CoASH. In the crude mitochondrial lysates we have used, an unknown compound accumulates with time, during incubation with alpha-keto isocaproic acid, CoASH and NAD. The compound, probably a CoA derivative, is more hydrophobic than isovaleryl-CoA.     

Biosynthesis of rainbow trout (Salmo gairdnerii) hemoglobins in vitro

Cell free systems were established to analyze the biosynthesis of trout hemoglobins I, II and III. HbI, II and III were synthesized in trout erythroid cell lysates as well as in a mRNA dependent rabbit reticulocyte lysate supplemented with trout erythroid cell polyA-RNA. The newly synthesized hemoglobins apparently contained the N alpha-acetyl modification at their alpha-chain amino terminals since they co-migrated with carrier trout hemoglobins that are known to contain the modification. This observation suggests that the acetylation is determined by the information encoded in the mRNA.     

Organization of the histone genes in the rainbow trout (Salmo gairdnerii)

Summary Twelve clones containing histone genes were isolated from a genomic trout library constructed in the vector Charon 4A. Each of the clones was found to contain a conserved 10.2-kb Eco RI fragment that contained one copy of each of the histones in the order H4-H2B-H1-H2A-H3, all of which are transcribed from the same strand. Genomic Southern blots indicate that these clusters are representative of the vast majority of the histone genes in the trout. Tandemly linked clusters were not found. Approximately 145 copies of this cluster are present in a trout sperm cell. Sequence analysis has shown the genes to be without introns and to show strong selection for codons ending in C or G. Consensus signals similar to those found in other histone genes are present in the flanking regions.     

Main serum protein of rainbow trout (Salmo gairdnerii): its biological properties and significance

• 1.1. Main serum α₁-protein (α₁P) of rainbow trout was purified and its biochemical and physico-pathological properties were studied.
• 2.2. α₁P was suggested to be a primitive protein having both properties of albumin and AFP in serum proteins of mammals according to the following results.
• 3.3. Molecular weight (75,000), two kinds of molecules (pI 4.55 and 5.05) and amino acid composition.
• 4.4. Dye- or ConA binding activity.
• 5.5. Estrogen binding activity and inhibitory effect on lymphoblastoid-forming activity.
• 6.6. Possible osmotic regulator.
• 7.7. Significant elevation of blood α₁P level in the course of hepatoma induction.

     

Some functional consequences of partial hepatectomy in rainbow trout (Salmo gairdnerii)

A partial hepatectomy (an average of 36% of hepatic mass removed) was performed in rainbow trout. Thirty days after this partial hepatic removal, the liver had recovered its initial weight. During regeneration the remaining liver was unable to maintain normal blood levels of protein, cholesterol and, partially, lipids which decrease after surgery. The results obtained show that functional and liver weight regeneration proceed at different rates throughout a given time course, weight recovering faster than complete functional restoration.     

Isolation and characterization of ferritin from the liver of the rainbow trout (Salmo gairdneri R.).

A method for the purification of ferritin from rainbow trout liver by heat extraction and gel filtration is described. The number of iron atoms varied from 500 to 2000 in purified ferritin. The neutral sugar composition detected was 86 mol of glucose, 24 mol of fucose, 12 mol of galactose, and 8 mol of mannose per mol of ferritin and apoferritin. Release of iron was achieved using low molecular weight chelating agents. The order of effectiveness of chelators was nitrilotriacetate greater than EDTA greater than citrate. Removal of the iron does not imply reduction of Fe3+. The rate of release of iron increased with decreasing pH. The slowest release was at pH 7.5. The endogenous chelator is not only sulphydrylic but seems to include carbohydrates that participate in the binding of Fe2+. Trout ferritin exhibits heterogeneity upon isoelectric focusing; four isoferritins with pI values of 4.5 to 4.85 were detected. This heterogeneity represents polymorphic, not polymer, forms. The amino acid composition differs from that of ferritins from other species. High concentrations of glutamic and aspartic acids, alanine, leucine, glycine, and lysine were detected along with low concentrations of methionine and cysteine.     

Lipid peroxidation enzyme system in rainbow trout (Salmo gairdnerii) skeletal muscle microsomes

1. A microsomal lipid peroxidation enzyme system in rainbow trout white skeletal muscle was identified and characterized. 2. This enzyme system is very similar to that found in other fish such as red hake, winter flounder and herring. 3. NADH-cytochrome b5 reductase is suggested to be the enzyme involved, because of the specific requirement for NADH as the electron donor, the inhibition of enzyme activity by p-hydroxy-mercuribenzoate and the involvement of chelated non-heme iron. 4. The activating and inhibitory effects of EDTA and KCN on lipid peroxidation enzyme system activity at different concentrations are discussed extensively in terms of the possible initiation reaction mechanism.     

Histone H4 and H2B genes in rainbow trout (Salmo gairdnerii)

Summary The complete nucleotide sequence of the 3.0-kb BamH I-Sst I restriction fragment contained within the rainbow trout genomic clone TH2 has been determined. This region contains the rainbow trout H4 and H2B histone genes and 5 and 3 flanking and spacer sequences, and represents the 5 half of the histone-gene cluster; the remaining half has been characterized previously. The genes are uninterrupted, and are transcribed from the same strand. The protein sequence of H4, as determined from the nucleic acid sequence, is the same as that derived for other vertebrate H4 proteins, although comparison of nucleotide sequences shows a great deal of sequence divergence, especially in the third base position. The amino acid sequence of H2B, though largely homologous to those of other vertebrate H2B proteins, displays some characteristic differences in primary structure. Consensus sequences noted in many other eukaryotic genes, as well as histone-specific consensus sequences, have been identified. An unusual feature of the spacer region between the H4 and H2B genes is the presence of a duplicated sequence 87 bp in length. The 5 and 3 ends of each repeat are complementary, and each repeat contains smaller repeated sequences internally, as well as a possible cruciform structure.     

Changes in plasma lipoproteins and tissue lipoprotein lipase and salt-resistant lipase activities during spawning in the rainbow trout (Salmo gairdnerii R.)

1. Lipoprotein lipase and salt-resistant lipase activities increased in the ovaries but decreased in the adipose tissue of female trout in the months leading up to spawning. 2. The activity of the plasma cholesterol esterifying enzyme increased significantly immediately prior to spawning. 3. Plasma lipoprotein concentrations decreased during the approach to spawning. 4. These studies suggest that the developing ovaries in the trout receive their nutrients by lipolysis of plasma lipoproteins as well as by vitellogenin uptake; differentiation of the roles of the lipid stores in different tissues is proposed.     

Adaptation of rainbow trout (Salmo gairdnerii) to sea water: Changes in calcitonin levels

• 1.1. The calcitonin content of the ultimobranchial body (UBB) and plasma levels of calcitonin, calcium and phosphate were measured in rainbow trout (Salmo gairdnerii) following their transfer from fresh to sea water.
• 2.2. The plasma calcium level remained unchanged throughout the experiment while the UBB calcitonin content, plasma calcitonin and plasma phosphate rose significantly during the hours immediately following transfer.
• 3.3. The levels of all three subsequently fall so that, 8–15 days later, a new equilibrium was established with lower than control (fresh water) levels of UBB calcitonin, plasma calcitonin and plasma phosphate.
• 4.4. It would appear, from these data, that calcitonin plays some part in the endocrine regulation of sea water transfer.

     

Viability control and oxygen consumption of isolated hepatocytes from thermally acclimated rainbow trout (Salmo gairdnerii)

Hepatocytes were isolated by collagenase perfusion of the liver from rainbow trout acclimated to 10 and 20 degrees C. The suitability of the stimulation of cellular respiration by succinate as criterion of viability was examined and discussed. Endogenous respiration rates of the hepatocytes were a function of cell size to the power of 0.8. Specific oxygen consumption of the hepatocytes and respiratory control ratios of the mitochondria in situ were independent of acclimation temperature.     

Nucleotide sequence of 5S ribosomal RNA from rainbow trout (Salmo gairdnerii) liver.

Staring from low molecular weight RNA obtained from rainbow trout (Salmo gairdnerii) liver, 5S ribosomal RNA (rRNA) was highly purified by successive chromatography on columns of DEAE-Sephadex A50 and Sephadex G100. Products of complete and partial digestions on this RNA with pancreatic ribonuclease (RNase A) [EC 3.1.4.22] and RNase T [EC 3.1.4.8] were isolated and sequenced by conventional and high-performance liquid chromatography (HPLC) procedures. The nucleotide sequence of this RNA thus established was compared with those of five other vertebrae 5S rRNAs, and the rates of base substitution per site per year were found to be nearly constant in these RNAs. The analyses of the partial digests of the trout 5S rRNA revealed several sites susceptible to RNase attack, which could be accounted for by the secondary structure model for eukaryotic 5S rRNAs proposed by Nishikawa and Takemura (1).     

A comparative study of the hepatotoxicity of monochlorobenzene in the rainbow trout (Salmo gairdnerii) and the Sprague-Dawley rat

Chlorobenzene (CB) was less hepatotoxic to trout than to rats. This difference could not be totally accounted for by reduced absorption in the trout and CB was metabolized in the trout. Glutathione concentrations in trout livers were 1/3 of those of the rat and prior depletion of the tripeptide led to irreversible binding of CB to trout liver protein equivalent to that of rats suffering extensive necrosis. No consistent correlation between glutathione content or protein binding and liver damage was seen in either species.