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1.
《Comparative biochemistry and physiology. A, Comparative physiology》1993,104(4):823-830
- 1.1. Indian River male broiler chickens growing from 7 to 28 days of age were fed diets containing 12, 18, 24 and 30% protein + 0 or 1 mg triiodothyronine (T3)/kg of diet to study energetic costs of lipogenesis and the use of various substrates for in vitro lipogenesis.
- 2.2. De novo lipid and CO2 production were determined in the presence of [1-14C]pyruvate, [2-14q]pyruvate, [3-14C]pyruvate, [2-14C]acetate and [U-14C]alanine.
- 3.3. Oxygen consumption was determined in mitochondrial preparations to estimate the energetic costs in expiants synthesizing lipid.
- 4.4. Radiolabeled CO2 derived from [1-14C]pyruvate was used as an estimate of coenzyme A availability in liver expiants. Lipids derived from [2-14C]pyruvate, [2-14C]acetate and [U-14C]alanine estimate relative substrate efficiency.
- 5.5. Labeled CO2 production from [1-14C]pyruvate was greatest in that group fed a 12% protein diet and least in the group fed a 30% protein diet.
- 6.6. In addition, T3 increased CO2 production from [1-14C]pyruvate.
- 7.7. The production of 14CO2 from the second carbon of pyruvate or acetate was increased by T3.
- 8.8. The low-protein diet (12% protein) increased (P <0.05) lipogenesis.
- 9.9. Adding T3 to the diets decreased carbon flux into lipid from all substrates, but increased CO2 production from all substrates without changing stage 3 and 4 respiration rates in mitochondrial preparations.
- 10.10. These observations imply that coenzyme A availability may have regulated de novo lipogenesis in the present study.
- 11.11. It was also concluded that previously noted effects of T3 on intermediary metabolism may involve metabolic pathways that do not involve changes in mitochondrial function.
2.
《Comparative biochemistry and physiology. A, Comparative physiology》1992,101(2):259-267
- 1.1. Changes in glomerular nitration rate (GFR), urine and blood properties and plasma catecholamines of carp were investigated during and following hypoxia.
- 2.2. GFR and urine flow decreased with increased urinary concentrations of bio-components, except protein, in the course of hypoxia.
- 3.3. Decreases in blood pH, and increases in haematocrit value and plasma K+, Ca2+, Mg2+, inorganic phosphate (Pi), ammonia, lactic acid and catecholamines (CAs) were observed as hypoxia progressed.
- 4.4. Increased GFR and urine flow, and higher values for urinary components, except protein, compared with those of the control were found in the initial post-stress stage.
- 5.5. The possible significance of increased plasma CAs in relation to changes in renal function in hypoxic carp is discussed.
3.
《Comparative biochemistry and physiology. A, Comparative physiology》1992,101(2):319-322
- 1.1. A charcoal adsorption assay demonstrated a large variance in androgen binding ability in female spotted hyaenas.
- 2.2. A positive correlation between plasma androgen binding ability and ovarian steroid concentrations was demonstrated in adult females.
- 3.3. The strong plasma binding affinity for testosterone and dihydrotestosterone (DHT) (nM) together with the lack of cortisol and weaker oestradiol-17β binding suggests that a specific androgen binding substance, possibly a protein, is present in adult females of this species.
- 4.4. The lack of high affinity binding in male spotted hyaenas is unusual and deserves further investigation.
- 5.5. Some androgen binding in all, including males and immature animals suggests that albumin may bind some plasma androgens in this species.
4.
《The International journal of biochemistry》1991,23(12):1445-1451
- 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
- 2.2. The enzyme has an apparent molecular weight of 24,000.
- 3.3. A Km value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
- 4.4. The enzyme is selectively activated and stabilized by Mn2+.
- 5.5. It requires high salt concentrations for stability and maximum activity.
- 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.
5.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1989,92(3):487-492
- 1.1. Subcellular distribution of (NA+, K+-ATPase and ouabain-insensitive ATPase (Mg2+-ATPase) are compared in branchial tissues of the euryhaline crab, Eriocheir sinensis, acclimated to fresh water.
- 2.2. Both the anterior and posterior gills contain cAMP-dependent protein kinase and endogenous protein substrate for phosphorylation.
- 3.3. Phosphorylation occurs in both “particulate” and “soluble” subcellular fractions but its stimulation by cAMP is restricted to the “soluble” fraction.
- 4.4. serotonin (5-HT) and dopamine receptors are present only in the “light particulate” fraction isolated from the posterior gills.
- 1.(a) Serotonin and dopamine have no effect on the phosphorylation observed in a subcellular fraction alone.
- 2.(b) Activation of the phosphorylation by serotonin and dopamine is found when the soluble fraction (source of cAMP-dependent protein kinase) is added to the fraction P3 from the posterior gills.
- 3.(c) No activation occurs with the fractions P3 as well as P1 or P2 (not shown) from anterior gills of fresh water crab.
- 4.(d) Cyproheptadine, a serotonin receptor antagonist, inhibits the 5-HT dependent increase in phosphorylation.
- 5.(e) The dopamine receptor antagonist, chlorpromazine, inhibits dopamine-stimulated phosphorylation.
- 6.5. Ouabain mimics the effect of cyproheptadine on the serotonin-stimulated phosphorylation found in the posterior gills.
6.
《Comparative biochemistry and physiology. A, Comparative physiology》1992,101(1):113-118
- 1.1. The effects of pressure on synaptic currents were examined in crayfish abdominal muscles.
- 2.2. Helium pressure (10.1 MPa) considerably decreased extracellulariy-recorded excitatory junctional potentials associated with increased short-term facilitation.
- 3.3. These effects could be mimicked by a reduction of [Ca2+]o, and partially compensated by an increase in [Ca2+]o.
- 4.4. Pressure also reduced the amplitude of the extracellular nerve terminal potentials (ENTP) by up to 25%, and significantly increased synaptic delay in a [Ca2+]o-dependent manner.
- 5.5. The interaction between compression and various [Ca2+]o were analysed in terms of an existing model of transmitter release. The results were consistent with the hypothesis that high pressure decreases the maximal Ca2+ influx into nerve terminals.
- 6.6. The decreased ENTP and increased synaptic delay suggest that additional processes may be involved in pressure effects on synaptic transmission.
7.
《The International journal of biochemistry》1993,25(11):1561-1564
- 1.1. The effect of incorporating D2O into the incubation medium on glycolysis and gluconeogenesis by hepatocytes from fasted rats was examined.
- 2.2. The substitution by heavy water, D2O, at concentrations from 10 to 40%, stimulated glucose uptake, lactate production and CO2 yields from glucose. At 10 mM glucose, 40% D2O doubled glucose uptake, increased CO2 production by 40%, and increased lactate production by 350%.
- 3.3. The stimulation of lactate production decreased at higher glucose concentrations, but was still substantial even at 80 mM glucose.
- 4.4. There was no effect on CO2 production above glucose concentrations of 30 mM.
- 5.5. Ten percent D2O showed little inhibition of lactate uptake, its oxidation and gluconeogenesis. At 40% D2O the inhibition ranged from 10 to 20%.
- 6.6. No effect of D2O on the rate of glucokinase or glucose-6-phosphatase was observed.
- 7.7. The concentration of fructose, 2,6-P was not affected by D2O
8.
《The International journal of biochemistry》1990,22(7):721-728
- 1.1. In the presence of insulin, 10−5 M 3,3',5-triiodothyronine (T3) treatment for 1/2 hr decreased fatty acid synthesis 35% only in adipocytes from lean rats, whereas at 10−11 M through 10−7M T3 the obese adipocytes had nearly a 20% increase in fatty acid synthesis.
- 2.2. A 2 hr pretreatment of adipocytes with 10−9 and 10−7 M T3 decreased insulin-stimulated fatty acid synthesis by nearly 20% in both lean and obese adipocytes.
- 3.3. In the absence of insulin, the 2 hr pretreatment with 10−9 M T3 resulted in a 45% increase in lean adipocyte fatty acid synthesis, though the obese adipocytes required at least 10−7 M T3 for 2 hr to increase the non-insulin-stimulated fatty acid synthesis by 50%.
- 4.4. At 10−9M T3 concentrations non-insulin-stimulated fatty acid synthesis was increased by 200% in lean adipose tissue explants, but obese adipose expiants were not significantly affected under these conditions.
- 5.5. The addition of 10−9 M T3 plus insulin to the explant media decreased fatty acid synthesis by 35% in both the lean and obese tissues.
- 6.6. The results also imply that the low T3 status of the obese rat may be contributory to the elevated fatty acid synthesis observed in obese adipocytes.
9.
《The International journal of biochemistry》1986,18(7):589-594
- 1.1. The properties of ATPase activity were studied with the cells at the early stationary phase of Saccharomycopsis fibuligera.
- 2.2. Optimal pH for the activity was approximately 7.
- 3.3. The activity was stimulated by Mg2+.
- 4.4. The activity was inhibited by NaF, DCCD, oligomycin, NaN3, NaVO3, or PCMB but not inhibited by ouabain.
10.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1988,89(2):499-502
- 1.1. To determine the physiological impact of Al on an organism stressed by low pH, the acid tolerant Libellula Julia was exposed to 30 mg/l Al at a pH of 2.3, 0.3 of a pH unit above its 96 hr lc50.
- 2.2. Aluminum at low pH, in comparison to low pH alone, caused highly significant losses of wet and ash weight and of body burdens of Na+ and Ca2+.
- 3.3. Since at the test pH Al exists as the ion, it would seem that a biological impact can be exerted not only by the ionized and unionized hydroxides, but also by Al3+.
11.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1986,83(4):875-879
- 1.1. A study has been made of phosphate-containing metabolites in single barnacle muscle fibers using phosphorus-31 nuclear magnetic resonance.
- 2.2. Spectra from single fibers (∼50 mg in wet weight) show major resonances from sugar phosphates, inorganic phosphate, arginine phosphate and the α, β and γ phosphorus atoms of ATP.
- 3.3. The approximate “free” concentration of each metabolite was determined by integration of the spectrum, using a sample of 1 M-methylene diphosphonic acid as a reference. A notable feature of the results obtained is that the concentrations of SP&Pi in freshly dissected fibers are low.
- 4.4. Time-dependent changes in 31P-NMR spectra indicate that ArP declines fairly slowly, while SP and Pi rises. The half-life of ArP at 26°C turns out to be about 8 hr. ATP remains relatively constant for the first 8 hr but disappears following the disappearance of ArP. As the intensity of the Pi resonance increases with time, it broadens and moves upfield, suggesting internal acidosis.
- 5.5. These results demonstrate that 31P-NMR can provide useful information about metabolism and its regulation in single barnacle muscle fibers.
12.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1988,89(2):513-516
- 1.1. The aggregation of erythrosomes within erythrophores of the squirrel fish (Myripristis occidentalis; belonging to the family Holocentridae) was, on pharmacological grounds, shown to be mediated by alpha2-adrenoceptors.
- 2.2. The erythrophores were shown to be controlled by adrenergic nerves activating the alpha2-adrenoceptors.
- 3.3. The erythrophores themselves were found to possess a K+-sensitive mechanism of aggregation.
- 4.4. Some similarities and differences of the alpha2-adrenoceptor-mediated chromatosome aggregation in melanophores and erythrophores are also discussed.
13.
《The International journal of biochemistry》1993,25(12):1963-1968
- 1.1. The native rat-kidney cortex Fructose-1,6-BPase is differentially regulated by Mg2+ and Mn2+.
- 2.2. Mg2+ binding to the enzyme is hyperbolic and large concentrations of the cation are non-inhibitory.
- 3.3. Mn2+ produces a 10-fold rise in Vmax higher than Mg2+. [Mn2+]0.5 is much larger than [Mg2+]0.5. At elevated [Mn2+] inhibition is observed.
- 4.4. Mg2+ and Mn2+ produce antagonistic effects on the inhibition of the enzyme by high substrate.
- 5.5. Fru-2,6-P2 inhibits the enzyme by rising the S0.5 and favouring a sigmoidal kinetics.
- 6.6. The inhibition by Fru-2,6-P2 is released by Mg2+ and more powerfully by Mn2+ increasing the I0.5.
14.
《The International journal of biochemistry》1993,25(4):575-579
- 1.1. Subcellular fractions of rat liver were assayed for PLA2 activity.
- 2.2. The PLA2 assay measures the release of [3 H]oleic acid from phospholipids, using labeled E. coli as substrate.
- 3.3. Nuclear fractions contained PLA2 activity, which was Ca2+ dependent and could not be explained from mitochondrial, microsomal or plasma membrane contamination.
- 4.4. The Vmax value of nuclear PLA2 is 0.30 ± 0.04 pmol oleic acid/min/mg protein; its Km value is 0.86±0.12μM, similar to that of mitochondrial PLA2.
- 5.5. We conclude that rat liver nuclei contain PLA2 activity.
15.
《Comparative biochemistry and physiology. A, Comparative physiology》1989,92(4):601-604
- 1.1. A half platelet preparation from Chinese crab (Eriocheir sinensis) gill is described which allows electrophysiological investigations of ion transport by gill epithelial monolayer when mounted in a modified Ussing chamber.
- 2.2. The resistance of these preparations equals half that of complete gill platelets (containing the gill epithelium and cuticle twice) indicating that cell damage during preparation of half platelets is negligible.
- 3.3. The transepithelial resistance (resistance of cuticle subtracted previously) was determined to be about 140 Ω cm2 when both sides are bathed with identical salines.
- 4.4. Similarities to the results obtained with perfused complete gills demonstrates the reliability of this preparation.
- 5.5. When identical salines are applied on both sides of the epithelium an outside positive transepithelial potential difference (PDte) up to 40 mV was measured.
- 6.6. The occurrence of such a high PDte under symmetric conditions and its sensitivity to CN− suggests the PDte to be generated by active transport processes.
16.
《The International journal of biochemistry》1993,25(8):1183-1187
- 1.1. Synaptic plasma membrane vesicles (SPMV) from rat brain synthesized ceramide-phosphoethanolamine (SpE), an analogue of sphingomyelin (SpC) from phosphatidylethanolamine (PE) and ceramide.
- 2.2. This reaction was catalyzed by PE: ceramide-phosphotransferase.
- 3.3. The presence of PC did not modify the SpE synthesis and PI and PS at twice PE concentration seemed to be activators; only PG was an inhibitor at all concentrations.
- 4.4. Some cations (Mg2+, Mn2+) were without effect, while Ca2+ increased transferase activity, so was interesting to study.
- 5.5. Transferase was compared with sialidase (external enzyme).
- 6.6. Kinetics other than those already performed by us were undertaken in order to confirm its location.
17.
- 1.1. Rainbow trout were acclimated to salt water (1.5, 2.0 or 3.0%, which means 40, 60 or 85% concentrated sea-water) and the electrolyte, glucose and cortisol concentrations of the plasma as well as the extra- and intracellular muscle space, the muscle electrolyte concentrations and the ATPase activity were analysed.
- 2.2. Plasma osmolality, Na+, Ca2+ and Mg2+ concentrations of the plasma had a maximum at 24 hr after the start of acclimation when acclimated to 3.0% salt water. Plasma osmolality, Na+ and Mg2+ concentrations were significantly higher during the whole acclimation time when exposed to 3.0% salt water.
- 3.3. Variations and regulations of ECS and ICS were clearly demonstrated. The intracellular electrolyte concentrations were also maximal at 24 hr.
- 4.4. The plasma glucose level was just slightly elevated, but the cortisol level clearly indicated a stress response at 24 hr.
- 5.5. The activity of gill Na-K-ATPase increased during the acclimation time.
- 6.6. The regulatory processes in trout during acclimation to salt water are compared with those occurring in tilapia and carp.
18.
《Comparative biochemistry and physiology. A, Comparative physiology》1992,101(3):451-454
- 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.
19.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1989,92(3):481-485
- 1.1. Carotenoid and retinoid forms were analysed by HPLC in various tissues of mature rainbow trout fed for 11 months (7–9°C) with astaxanthin (50 and 100 mg/kg diet) or canthaxanthin (100 mg/kg diet).
- 2.2. Decreasing concentrations of canthaxanthin, echinenone and β-carotene, but no retinol1, were found in the liver and skin of canthaxanthin-fed fish.
- 3.3. Higher retinol2 concentrations were found in ovaries and testes of astaxanthin-fed fish compared to canthaxanthin and control groups.
- 4.4. A new metabolic pathway for direct conversion of astaxanthin into retinol2 in gonads is proposed.
20.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1988,89(2):503-505
- 1.1. Microelectrodes have been used to measure K+ activities and electrical potential differences between the perivitelline fluid (pvf) of the eggs of pike (Esox lucius) and surrounding water in a range of pH, calcium and aluminium concentrations.
- 2.2. Potential differences between pvf and water are decreased by Ca2+ (10−3 M) while Al3+ (18 × 10−6 M) reverses the polarity of the potential difference.
- 3.3. K+ activities in the pvf of eggs in 10−4M KCl + 10−5M NaCl are decreased by Ca2+(10−3 M).
- 4.4. The results are discussed with reference to ion-exchange theory and chorion permeability.