Temperature and enzyme activity in poikilotherms. Isocitrate dehydrogenases in rainbow-trout liver.
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ABSTRACT:
SUBMITTER: Moon TW
PROVIDER: S-EPMC1177070 | biostudies-other | 1971 Aug
REPOSITORIES: biostudies-other
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Project description:1. The properties of fructose diphosphatase from the liver of rainbow trout (Salmo gairdnerii) were examined over the physiological temperature range of the organism. 2. Saturation curves for substrate (fructose 1,6-diphosphate) and a cofactor (Mg(2+)) are sigmoidal, and Hill plots of the results suggest a minimum of two interacting fructose 1,6-diphosphate sites and two interacting Mg(2+) sites per molecule of enzyme. 3. Mn(2+)-saturation curves are hyperbolic, and the K(a) for Mn(2+), which inhibits the enzyme at high concentrations, is 50-100-fold lower than the K(a) for Mg(2+). 4. Fructose diphosphatase is inhibited by low concentrations of AMP; this inhibition appears to be decreased and reversed by increasing the concentrations of Mg(2+) and Mn(2+). Higher concentrations of AMP are required to inhibit the trout fructose diphosphatase in the presence of Mn(2+). 5. The affinities of fructose diphosphatase for fructose diphosphate and Mn(2+) appear to be temperature-independent, whereas the affinities for Mg(2+) and AMP are highly temperature-dependent. 6. The pH optimum of the enzyme depends on the concentrations of Mg(2+) and Mn(2+). In addition, pH determines the K(a) for Mg(2+); at high pH, K(a) for Mg(2+) is lowered. 7. The enzyme is inhibited by Ca(2+) and Zn(2+), and the inhibition is competitive with respect to both cations. 8. The possible roles of these ions and AMP in the modulation of fructose diphosphatase and gluconeogenic activity are discussed in relation to temperature adaptation.
| S-EPMC1187510 | biostudies-other
Project description:In this project, effects of chronic temperature changes on the transcriptome of the rainbow trout heart (Oncorhynchus mykiss) were examined. Ectothermic animals of north-temperate latitudes experience large seasonal changes in temperature which strongly affect the rate of body functions. To compensate for the effects of temperature changes ectotherms can respond to chronic temperature changes by increasing the quantity of tissue or enzyme needed for different physiological tasks, or by expressing proteins isoforms which are more appropriate for the new thermal conditions. On the other hand, proteins which are needed in lesser amounts in the new thermal regime could be depressed or down-regulated. Although expression of proteins can be changed by multiple mechanisms during synthesis and degradation, temperature dependent changes in transcription of genes is probably the most important factor in modifying the proteome of the tissues. Rainbow trout are active throughout their thermal tolerance range (0-25°C). Maintenance of adequate cardiac function at different thermal conditions requires a thorough change of the cardiac phenotype which appears as compensatory changes in relative heart mass, energy metabolism, nervous and humoral control of cardiac contractility and in electrical and mechanical properties of the trout heart. Such an extensive structural and functional remodeling of the heart probably necessitates both qualitative and quantitative changes among the numerous macromolecules which constitute the cardiac phenotype and cannot, therefore, be solely based on posttranslational modification of proteins but is expected to require differential gene expression. As a power supply of the circulatory system, the heart is in the focal point of physiological plasticity and sets limits for the activity level of the animal in different thermal conditions. Although several aspects of heart function have been studied in thermally acclimated fish and a number of structural changes have been noticed on exposure to different temperatures, the cellular and molecular mechanisms involved in chronic thermal stress of the fish heart are only partially elucidated. An interesting and poorly examined feature of the cold-acclimated phenotype of the trout heart is the increased heart mass which attenuates the depressive effect of low temperature on cardiac pump function. The heart is a complex organ composed of multiple tissues which together provide the system all necessary qualifications for cardiac pump function. In addition to the contractile and metabolic machinery of the cardiac myocytes, the amount and quality of the extracellular matrix also contribute to the properties of the heart as a muscular pump. Due to the complexity of the heart an enormous amounts of research efforts are needed to find out and examine all crucial aspects of cardiac plasticity required for thermal acclimation. In this regard the screening of gene expression by cDNA micro arrays might provide a broader view to genomic basis of cardiac remodeling under changing temperatures and aid to reveal the candidate genes which are important for thermal acclimation and which might remain unnoticed by traditional biochemical and physiological methods. In the present study we the steady-state effects of temperature acclimation on gene expression of the rainbow trout heart were screened by micro array analysis. Keywords: parallel sample
2005-02-19 | GSE2277 | GEO
Project description:In this project, effects of chronic temperature changes on the transcriptome of the rainbow trout heart (Oncorhynchus mykiss) were examined. Ectothermic animals of north-temperate latitudes experience large seasonal changes in temperature which strongly affect the rate of body functions. To compensate for the effects of temperature changes ectotherms can respond to chronic temperature changes by increasing the quantity of tissue or enzyme needed for different physiological tasks, or by expressing proteins isoforms which are more appropriate for the new thermal conditions. On the other hand, proteins which are needed in lesser amounts in the new thermal regime could be depressed or down-regulated. Although expression of proteins can be changed by multiple mechanisms during synthesis and degradation, temperature dependent changes in transcription of genes is probably the most important factor in modifying the proteome of the tissues. Rainbow trout are active throughout their thermal tolerance range (0-25°C). Maintenance of adequate cardiac function at different thermal conditions requires a thorough change of the cardiac phenotype which appears as compensatory changes in relative heart mass, energy metabolism, nervous and humoral control of cardiac contractility and in electrical and mechanical properties of the trout heart. Such an extensive structural and functional remodeling of the heart probably necessitates both qualitative and quantitative changes among the numerous macromolecules which constitute the cardiac phenotype and cannot, therefore, be solely based on posttranslational modification of proteins but is expected to require differential gene expression. As a power supply of the circulatory system, the heart is in the focal point of physiological plasticity and sets limits for the activity level of the animal in different thermal conditions. Although several aspects of heart function have been studied in thermally acclimated fish and a number of structural changes have been noticed on exposure to different temperatures, the cellular and molecular mechanisms involved in chronic thermal stress of the fish heart are only partially elucidated. An interesting and poorly examined feature of the cold-acclimated phenotype of the trout heart is the increased heart mass which attenuates the depressive effect of low temperature on cardiac pump function. The heart is a complex organ composed of multiple tissues which together provide the system all necessary qualifications for cardiac pump function. In addition to the contractile and metabolic machinery of the cardiac myocytes, the amount and quality of the extracellular matrix also contribute to the properties of the heart as a muscular pump. Due to the complexity of the heart an enormous amounts of research efforts are needed to find out and examine all crucial aspects of cardiac plasticity required for thermal acclimation. In this regard the screening of gene expression by cDNA micro arrays might provide a broader view to genomic basis of cardiac remodeling under changing temperatures and aid to reveal the candidate genes which are important for thermal acclimation and which might remain unnoticed by traditional biochemical and physiological methods. In the present study we the steady-state effects of temperature acclimation on gene expression of the rainbow trout heart were screened by micro array analysis.
2010-06-10 | E-GEOD-2277 | biostudies-arrayexpress
Project description:1. The calculated energy charge of the liver cell from migrating salmon is very low (0.464), in keeping with the extended starvation and high rates of muscular and biosynthetic activity of these organisms. 2. Affinity of fructose 1,6-diphosphatase for substrate increases with a decrease in temperature. 3. Arrhenius plots of the saturation kinetics are complex and suggest an interconversion of one or more forms of the enzyme; this interconversion is dependent on the identity of the cofactor. 4. Affinity of salmon fructose 1,6-diphosphatase for its allosteric inhibitor (AMP) is lower than in other fructose 1,6-diphosphatases and this enzyme-AMP interaction is largely insensitive to temperature. The functional significance of diminished AMP-sensitivity is that it allows normal or high fructose 1,6-diphosphatase activity during a low energy charge. 5. These findings suggest mechanisms for the maintenance of high rates of gluconeogenesis in salmon during spawning migration.
| S-EPMC1185194 | biostudies-other
Project description:1. The properties of fructose diphosphatase from liver of South American lungfish (Lepidosiren paradoxa) were examined. 2. Saturation curves for substrate (fructose diphosphate) and both cofactors (Mn(2+) and Mg(2+)) are sigmoidal and Hill plots of these results suggest about 2 interacting substrate and cofactor sites/molecule of enzyme. 3. Mn(2+) is an efficient positive modulator of the enzyme and K(a) for Mn(2+) is about 20-30-fold lower than the K(a) for Mg(2+). 4. Lungfish fructose diphosphatase is inhibited by low concentrations of AMP, and the affinity of the enzyme for AMP is insensitive to temperature. 5. The affinities of fructose diphosphatase for fructose diphosphate and Mn(2+) appear to be dependent on temperature, whereas affinity for Mg(2+) is temperature-independent. 6. The pH optimum of the enzyme depends on the presence of the particular cofactor. As pH increases, the K(a) values of both cations are lowered, maximum velocities are increased and the saturation curves for cofactor become hyperbolic. 7. The possible roles of these ions, pH and substrate in the modulation of fructose diphosphatase and gluconeogenic activity in the lungfish are discussed in relation to aestivation and temperature adaptation.
| S-EPMC1187762 | biostudies-other
Project description:Vibrio anguillarum is an extracellular bacterial pathogen that is a causative agent of vibriosis in finfish and crustaceans with mortality rates ranging from 30% to 100%. Mutations in central metabolism (glycolysis and the TCA cycle) of intracellular pathogens often result in attenuated virulence due to depletion of required metabolic intermediates; however, it was not known whether mutations in central metabolism would affect virulence in an extracellular pathogen such as V. anguillarum.Seven central metabolism mutants were created and characterized with regard to growth in minimal and complex media, expression of virulence genes, and virulence in juvenile rainbow trout (Oncorhynchus mykiss). Only the isocitrate dehydrogenase (icd) mutant was attenuated in virulence against rainbow trout challenged by either intraperitoneal injection or immersion. Further, the icd mutant was shown to be immunoprotective against wild type V. anguillarum infection. There was no significant decrease in the expression of the three hemolysin genes detected by qRT-PCR. Additionally, only the icd mutant exhibited a significantly decreased growth yield in complex media. Growth yield was directly related to the abundance of glutamate. A strain with a restored wild type icd gene was created and shown to restore growth to a wild type cell density in complex media and pathogenicity in rainbow trout.The data strongly suggest that a decreased growth yield, resulting from the inability to synthesize ?-ketoglutarate, caused the attenuation despite normal levels of expression of virulence genes. Therefore, the ability of an extracellular pathogen to cause disease is dependent upon the availability of host-supplied nutrients for growth. Additionally, a live vaccine strain could be created from an icd deletion strain.
| S-EPMC5686843 | biostudies-literature
Project description:Cyanobacterial blooms have an impact on the aquatic ecosystem due to the production of toxins (e.g. microcystins, MCs), which constrain fish health or even cause fish death. However the toxicokinetics of the most abundant toxin, microcystin-LR (MC-LR), are not yet fully understood. To investigate the uptake mechanism, the novel Oatp1d1 in rainbow trout (rtOatp1d1) was cloned, identified and characterized. The cDNA isolated from a clone library consisted of 2772bp containing a 2115bp open reading frame coding for a 705 aa protein with an approximate molecular mass of 80kDa. This fish specific transporter belongs to the OATP1 family and has most likely evolved from a common ancestor of OATP1C1. Real time PCR analysis showed that rtOatp1d1 is predominantly expressed in the liver, followed by the brain while expression in other organs was not detectable. Transient transfection in HEK293 cells was used for further characterization. Like its human homologues OATP1A1, OATP1B1 and OATP1B3, rtOatp1d1 displayed multi-specific transport including endogenous and xenobiotic substrates. Kinetic analyses revealed a Km value of 13.9μM and 13.4μM for estrone-3-sulfate and methotrexate, respectively and a rather low affinity for taurocholate with a Km value of 103μM. Furthermore, it was confirmed that rtOatp1d1 is a MC-LR transporter and therefore most likely plays a key role in the susceptibility of rainbow trout to MC intoxications.
| S-EPMC4254065 | biostudies-literature
Project description:Rainbow trout myotubes treated with cortisol and/or infected with Piscirickettsia salmonis - Raw sequence reads
| PRJNA732666 | ENA
Project description:Gut bacteria of rainbow trout fed diets supplemented with Cellobiose
| PRJNA868155 | ENA
Project description:Rainbow trout skeletal muscle challenging with IPNV - Raw sequence reads
| PRJNA629987 | ENA