scholarly journals Temperature affects the diffusion of small molecules through cytosol of fish muscle

1987 ◽  
Vol 129 (1) ◽  
pp. 191-203 ◽  
Author(s):  
B. D. Sidell ◽  
J. R. Hazel
Keyword(s):  
Small Molecules ◽  
Diffusion Coefficients ◽  
White Perch ◽  
Thermal Sensitivity ◽  
Fish Muscle ◽  
Temperature Acclimation ◽  
Effect Of Temperature ◽  
Relative Temperature ◽  
D Values

Undiluted cytosolic extracts were prepared from fast glycolytic muscle tissue of white perch (Morone americanus). Diffusion coefficients (D) through the cytosol preparations were estimated in vitro for a series of selected low molecular weight compounds using an experimental diffusion chamber. Determinations were made at 5 degrees and 25 degrees C to assess thermal sensitivity of the process. Non-metabolizable analogues of naturally occurring compounds were employed to avoid chemical alteration of solutes by the catalytically competent preparations during diffusion experiments. Kinematic viscosity of cytosolic extracts, which is a major determinant of diffusive resistance, increases from 2.94 +/− 0.06 to 5.35 +/− 0.02 X 10(−2) cm2 s-1 between temperatures of 25 degrees and 5 degrees C (Q10 = 1.35 +/− 0.01). The diffusion coefficients (D) of D-lactic acid are 2.26 +/− 0.84 and 0.79 +/− 0.15 X 10(−6) cm2s-1 at 25 degrees and 5 degrees C, respectively (Q10 = 1.84 +/− 0.36). The D values of 2-deoxyglucose are 2.87 +/− 1.01 and 1.22 +/− 0.36 X 10(−6) cm2s-1 at 25 degrees and 5 degrees C (Q10 = 1.75 +/− 0.54). The D values of Ca2+ are 2.47 +/− 0.28 and 1.09 +/− 0.36 X 10(−6) cm2s-1 at 25 degrees and 5 degrees C (Q10 = 2.04 +/− 0.36). The D values for the ATP analogue, AMP-PNP, are 0.87 +/− 0.33 and 0.81 +/− 0.15 X 10(−6) cm2s-1 at 25 degrees and 5 degrees C (Q10 = 0.98 +/− 0.12). AMP-PNP is the only compound tested which did not show significant thermal sensitivity of diffusion. Recently reported changes in muscle cell ultrastructure induced by temperature acclimation of fishes may serve to counteract the effect of temperature change on diffusion of key small molecules through the aqueous cytoplasm, thus maintaining flux rates between cellular compartments. These mechanisms may be of considerable import in achieving relative temperature independence of cellular function that is characteristic of many eurythermal aquatic animals.

scholarly journals THERMAL ACCLIMATION ALTERS BOTH ADRENERGIC SENSITIVITY AND ADRENOCEPTOR DENSITY IN CARDIAC TISSUE OF RAINBOW TROUT

1993 ◽  
Vol 181 (1) ◽  
pp. 27-48 ◽  
Author(s):  
J. E. Keen ◽  
D. M. Vianzon ◽  
A. P. Farrell ◽  
G. F. Tibbits
Keyword(s):  
Rainbow Trout ◽  
Cardiac Tissue ◽  
Radioligand Binding ◽  
Temperature Acclimation ◽  
Effect Of Temperature ◽  
Acclimation Temperature ◽  
Binding Studies ◽  
Tension Development

We examined the effect of temperature acclimation on the sensitivity of the rainbow trout heart to adrenaline and on the density of beta-adrenoceptors. The sensitivity of the heart was assessed using in situ working perfused heart and in vitro isometric ventricular strip preparations. When tested in situ and at acclimation temperature, hearts from fish acclimated to 8°C were approximately 10-fold more sensitive to adrenaline-supplemented perfusate than were hearts from fish acclimated to 18°C. The concentrations required for half-maximal stimulation (EC50) of myocardial power output were 1.9×10- 8 mol l-1 adrenaline and 1.7×10-7 mol l-1 adrenaline for hearts acclimated to 8°C and 18°C, respectively. In vitro, isometric ventricular strip preparations demonstrated a similar increase in adrenergic sensitivity with cold-acclimation. The EC50 values for maximal tension development were 2.7×10-7 mol l-1 adrenaline (8°C-acclimated) and 1.1×10-6 mol l-1 adrenaline (18°C-acclimated) when tested at acclimation temperature. This shift in adrenergic sensitivity was a function of the temperature acclimation because changes in bath temperature per se, either from 8°C to 18°C for 8°C- acclimated hearts or from 18°C to 8°C for 18°C-acclimated hearts, had no significant effect on the concentration-response curve for adrenaline. We conducted radioligand binding studies with [125I]iodocyanopindolol and propranolol to quantify the beta-adrenoceptor density (Bmax) of both homogenates and isolated sarcolemmal fractions of ventricles from rainbow trout acclimated to either 8°C or 18°C. The Bmax for isolated sarcolemmal fractions was significantly higher in the 8°C-acclimated group, but the Bmax of ventricular homogenates was not significantly different in the two acclimation groups. No significant differences in dissociation constant (Kd) were apparent in either the homogenates or sarcolemmal fractions. These results suggest that cardiac tissue from rainbow trout acclimated to 8°C has a greater cell surface adrenoceptor population available for beta-antagonist binding. This might explain the heightened cardiac sensitivity to adrenaline observed in situ and in vitro in 8°C-acclimated fish.

scholarly journals Plate-Based Respirometry to Assess Thermal Sensitivity of Zebrafish Embryo Bioenergetics in situ

2021 ◽  
Vol 12 ◽  
Author(s):  
Erik Rollwitz ◽  
Martin Jastroch
Keyword(s):  
Oxygen Consumption ◽  
Thermal Sensitivity ◽  
Coupling Efficiency ◽  
Temperature Acclimation ◽  
Effect Of Temperature ◽  
Proton Leak ◽  
Zebrafish Embryos ◽  
Atp Production ◽  
Extracellular Flux

Oxygen consumption allows measuring the metabolic activity of organisms. Here, we adopted the multi-well plate-based respirometry of the extracellular flux analyzer (Seahorse XF96) to investigate the effect of temperature on the bioenergetics of zebrafish embryos (Danio rerio) in situ. We show that the removal of the embryonic chorion is beneficial for oxygen consumption rates (OCR) and penetration of various mitochondrial inhibitors, and confirm that sedation reduces the variability of OCR. At 48h post-fertilization, embryos (maintained at a routine temperature of 28°C) were exposed to different medium temperatures ranging from 18°C to 37°C for 20h prior OCR measurement. Measurement temperatures from 18°C to 45°C in the XF96 were achieved by lowering the room temperature and active in-built heating. At 18°C assay temperature, basal OCR was low due to decreased ATP-linked respiration, which was not limited by mitochondrial power, as seen in substantial spare respiratory capacity. Basal OCR of the embryos increased with assay temperature and were stable up to 37°C assay temperature, with pre-exposure of 37°C resulting in more thermo-resistant basal OCR measured at 41°C. Adverse effects of the mitochondrial inhibitor oligomycin were seen at 37°C and chemical uncouplers disrupted substrate oxidation gradually with increasing assay temperature. Proton leak respiration increased at assay temperatures above 28°C and compromised the efficiency of ATP production, calculated as coupling efficiency. Thus, temperature impacts mitochondrial respiration by reduced cellular ATP turnover at lower temperatures and by increased proton leak at higher temperatures. This conclusion is coherent with the assessment of heart rate, an independent indicator of systemic metabolic rate, which increased with exposure temperature, peaking at 28°C, and decreased at higher temperatures. Collectively, plate-based respirometry allows assessing distinct parts of mitochondrial energy transduction in zebrafish embryos and investigating the effect of temperature and temperature acclimation on mitochondrial bioenergetics in situ.

THE EFFECT OF TEMPERATURE ACCLIMATION ON PATHWAYS OF GLUCOSE METABOLISM IN THE TROUT

1962 ◽  
Vol 40 (2) ◽  
pp. 261-270 ◽  
Author(s):  
P. W. Hochachka ◽  
F. R. Hayes
Keyword(s):  
Glucose Metabolism ◽  
Salvelinus Fontinalis ◽  
Liver Glycogen ◽  
Temperature Acclimation ◽  
Pentose Phosphate ◽  
Effect Of Temperature ◽  
Fat Synthesis ◽  
Epaxial Muscle

In warm (15 °C) acclimated Salvelinus fontinalis, (i) the respiration of epaxial muscle homogenates was almost completely inhibited by iodoacetate; (ii) C14O2 was incorporated primarily into positions 3, 4 of liver glycogen, and (iii) in vivo and in vitro glucose-1-C14 metabolism was similar to that of glucose-6-C14. The results suggest a predominant participation of the Embden–Meyerhof path.In cold-acclimated (4 °C) trout, (i) the respiration of muscle homogenates was higher and less sensitive to iodoacetate; (ii) less of the C14O2 incorporated into liver glycogen appeared in carbon atoms 3 and 4; (iii) there was a sharp discrimination between the metabolism of C1- and C6- labelled glucose; and (iv) acetate-1-C14 oxidation was lower, but incorporation into fat was higher than in the warm-adapted fish. An activation of the pentose phosphate cycle in conjunction with a higher rate of fat synthesis during cold compensation could account for all of the foregoing data.

The development of dormancy in bulblets of Lilium speciosum generated in vitro. II. The effect of temperature

1990 ◽  
Vol 80 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Isabelle Delvallee ◽  
Annie Paffen ◽  
Geert-Jan De Klerk
Keyword(s):  
Effect Of Temperature ◽  
Lilium Speciosum

Effect of Temperature on ADP-Induced Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 183-189
Author(s):  
C. A Praga ◽  
E. M Pogliani
Keyword(s):  
Platelet Aggregation ◽  
Incubation Period ◽  
Room Temperature ◽  
Important Variable ◽  
Practical Significance ◽  
Effect Of Temperature ◽  
Induce Platelet Aggregation ◽  
Cuvette Holder ◽  
Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

Effect of Temperature, Velocity Gradient and I.V. Heparin on in Vitro Blood Coagulation and Platelet Aggregation

1967 ◽  
Vol 17 (01/02) ◽  
pp. 112-119 ◽  
Author(s):  
L Dintenfass ◽  
M. C Rozenberg
Keyword(s):  
Blood Coagulation ◽  
Velocity Gradient ◽  
Elevated Temperatures ◽  
Morphological Changes ◽  
Effect Of Temperature ◽  
Clotting Time ◽  
Progressive Change ◽  
Aggregation Of Platelets ◽  
Microscopic Techniques

SummaryA study of blood coagulation was carried out by observing changes in the blood viscosity of blood coagulating in the cone-in-cone viscometer. The clots were investigated by microscopic techniques.Immediately after blood is obtained by venepuncture, viscosity of blood remains constant for a certain “latent” period. The duration of this period depends not only on the intrinsic properties of the blood sample, but also on temperature and rate of shear used during blood storage. An increase of temperature decreases the clotting time ; also, an increase in the rate of shear decreases the clotting time.It is confirmed that morphological changes take place in blood coagula as a function of the velocity gradient at which such coagulation takes place. There is a progressive change from the red clot to white thrombus as the rates of shear increase. Aggregation of platelets increases as the rate of shear increases.This pattern is maintained with changes of temperature, although aggregation of platelets appears to be increased at elevated temperatures.Intravenously added heparin affects the clotting time and the aggregation of platelets in in vitro coagulation.

Applicability of Instability Index for In vitro Protein Stability Prediction

2019 ◽  
Vol 26 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Dilani G. Gamage ◽  
Ajith Gunaratne ◽  
Gopal R. Periyannan ◽  
Timothy G. Russell
Keyword(s):  
Protein Stability ◽  
Caulobacter Crescentus ◽  
Effect Of Temperature ◽  
Instability Index ◽  
Dipeptide Composition ◽  
Experimental Conditions ◽  
The Stability ◽  
Vitro Protein

Background: The dipeptide composition-based Instability Index (II) is one of the protein primary structure-dependent methods available for in vivo protein stability predictions. As per this method, proteins with II value below 40 are stable proteins. Intracellular protein stability principles guided the original development of the II method. However, the use of the II method for in vitro protein stability predictions raises questions about the validity of applying the II method under experimental conditions that are different from the in vivo setting. Objective: The aim of this study is to experimentally test the validity of the use of II as an in vitro protein stability predictor. Methods: A representative protein CCM (CCM - Caulobacter crescentus metalloprotein) that rapidly degrades under in vitro conditions was used to probe the dipeptide sequence-dependent degradation properties of CCM by generating CCM mutants to represent stable and unstable II values. A comparative degradation analysis was carried out under in vitro conditions using wildtype CCM, CCM mutants and two other candidate proteins: metallo-β-lactamase L1 and α -S1- casein representing stable, borderline stable/unstable, and unstable proteins as per the II predictions. The effect of temperature and a protein stabilizing agent on CCM degradation was also tested. Results: Data support the dipeptide composition-dependent protein stability/instability in wt-CCM and mutants as predicted by the II method under in vitro conditions. However, the II failed to accurately represent the stability of other tested proteins. Data indicate the influence of protein environmental factors on the autoproteolysis of proteins. Conclusion: Broader application of the II method for the prediction of protein stability under in vitro conditions is questionable as the stability of the protein may be dependent not only on the intrinsic nature of the protein but also on the conditions of the protein milieu.

Conjugates of Classical DNA/RNA Binder with Nucleobase: Chemical, Biochemical and Biomedical Applications

2019 ◽  
Vol 26 (30) ◽  
pp. 5609-5624
Author(s):  
Dijana Saftić ◽  
Željka Ban ◽  
Josipa Matić ◽  
Lidija-Marija Tumirv ◽  
Ivo Piantanida
Keyword(s):  
Molecular Weight ◽  
Small Molecules ◽  
Biomedical Applications ◽  
Protein Targets ◽  
New Class ◽  
Rna Targets ◽  
Covalently Linked ◽  
Structural Aspects

: Among the most intensively studied classes of small molecules (molecular weight < 650) in biomedical research are small molecules that non-covalently bind to DNA/RNA, and another intensively studied class is nucleobase derivatives. Both classes have been intensively elaborated in many books and reviews. However, conjugates consisting of DNA/RNA binder covalently linked to nucleobase are much less studied and have not been reviewed in the last two decades. Therefore, this review summarized reports on the design of classical DNA/RNA binder – nucleobase conjugates, as well as data about their interactions with various DNA or RNA targets, and even in some cases protein targets are involved. According to these data, the most important structural aspects of selective or even specific recognition between small molecule and target are proposed, and where possible related biochemical and biomedical aspects were discussed. The general conclusion is that this, rather new class of molecules showed an amazing set of recognition tools for numerous DNA or RNA targets in the last two decades, as well as few intriguing in vitro and in vivo selectivities. Several lead research lines show promising advancements toward either novel, highly selective markers or bioactive, potentially druggable molecules.

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