scholarly journals Temperature Effects on Haemolymph Acid-Base Status In Vivo and In Vitro in the Two-Striped Grasshopper Melanoplus Bivittatus

1988 ◽  
Vol 140 (1) ◽  
pp. 421-435 ◽  
Author(s):  
JON M. HARRISON
Keyword(s):  
Body Temperature ◽  
Carbonic Acid ◽  
Temperature Shift ◽  
Effect Of Temperature ◽  
Locomotory Activity ◽  
Acid Base ◽  
Protein Dissociation ◽  
Acid Base Status

In this study, I examine the effect of temperature on haemolymph acid-base status in vivo and in vitro in the two-striped grasshopper Melanoplus bivittatus. Melanoplus bivittatus experience wide (up to 40 °C) diurnal body temperature fluctuations in the field, but maintain body temperature relatively constant during sunny days by behavioural thermoregulation. Haemolymph pH was statistically constant (7.12) between 10 and 25°C, but decreased by −0.017 units °C− from 25 to 40°C. Relative alkalinity and fractional protein dissociation were conserved only at body temperatures at which feeding and locomotory activity occur, above 20°C. Haemolymph total CO2 (Ctot) increased from 10 to 20°C and decreased from 20 to 40°C. Haemolymph Pco2 increased from 10 to 20°C and was statistically constant between 20 and 40°C. Carbonic acid pKapp in haemolymph was 6.122 at 35°C, and decreased with temperature by −0.0081 units°C−1. Haemolymph buffer value averaged −35mequivl−1pHunit−1. Haemolymph pH changes with temperature were small (less than −0.004 units°C−1) in vitro at constant Pco2. Therefore, passive physicochemical effects cannot account for the pattern of acid-base regulation in vivo. The temperature shift from 10 to 20°C was accompanied by a net addition of 4.2-6.2 mmoll−1 of bicarbonate equivalents to the haemolymph. The temperature shift from 20 to 40°C was accompanied by a net removal of 10–14 mmoll−1 of bicarbonate equivalents from the haemolymph. Haemolymph acid-base regulation in vivo during temperature changes is dominated by active variation of bicarbonate equivalents rather than by changes in Pco2 as observed for most other air-breathers.

Use of protein microarray to identify gene expression changes ofYersinia pestisat different temperatures

2011 ◽  
Vol 57 (4) ◽  
pp. 287-294 ◽  
Author(s):  
Bei Li ◽  
Yafang Tan ◽  
Jingyu Guo ◽  
Baizhong Cui ◽  
Zuyun Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Protein Microarray ◽  
Temperature Shift ◽  
Promising Technique ◽  
Different Temperatures ◽  
Monitoring Gene Expression ◽  
Identify Gene Expression

Yersinia pestis is a bacterium that is transmitted between fleas, which have a body temperature of 26 °C, and mammalian hosts, which have a body temperature of 37 °C. To adapt to the temperature shift, phenotype variations, including virulence, occur. In this study, an antigen microarray including 218 proteins of Y. pestis was used to evaluate antibody responses in a pooled plague serum that was unadsorbed, adsorbed by Y. pestis cultivated at 26 °C, or adsorbed by Y. pestis cultivated at 26 and 37 °C to identify protein expression changes during the temperature shift. We identified 12 proteins as being expressed at 37 °C but not at 26 °C, or expressed at significantly higher levels at 37 °C than at 26 °C. The antibodies against 7 proteins in the serum adsorbed by Y. pestis cultivated at 26 and 37 °C remained positive, suggesting that they were not expressed on the surface of Y. pestis in LB broth in vitro or specifically expressed in vivo. This study proved that protein microarray and antibody profiling comprise a promising technique for monitoring gene expression at the protein level and for better understanding pathogenicity, to find new vaccine targets against plague.

Cellular actions of cAMP on HCO3(-)-secreting cells of rabbit CCD: dependence on in vivo acid-base status

1994 ◽  
Vol 266 (4) ◽  
pp. F528-F535 ◽  
Author(s):  
C. Emmons ◽  
J. B. Stokes
Keyword(s):  
Anion Exchanger ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Disulfonic Acid ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Acid Base ◽  
Acid Base Status

HCO3- secretion by cortical collecting duct (CCD) occurs via beta-intercalated cells. In vitro CCD HCO3- secretion is modulated by both the in vivo acid-base status of the animal and by adenosine 3',5'-cyclic monophosphate (cAMP). To investigate the mechanism of cAMP-induced HCO3- secretion, we measured intracellular pH (pHi) of individual beta-intercalated cells of CCDs dissected from alkali-loaded rabbits perfused in vitro. beta-Intercalated cells were identified by demonstrating the presence of an apical anion exchanger (cell alkalinization in response to removal of lumen Cl-). After 180 min of perfusion to permit decrease of endogenous cAMP, acute addition of 0.1 mM 8-bromo-cAMP or 1 microM isoproterenol to the bath caused a transient cellular alkalinization (> 0.20 pH units). In the symmetrical absence of either Na+, HCO3-, or Cl-, cAMP produced no change in pHi. Basolateral dihydrogen 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (0.1 mM) for 15 min before cAMP addition also prevented this alkalinization. In contrast to the response of cells from alkali-loaded rabbits, addition of basolateral cAMP to CCDs dissected from normal rabbits resulted in an acidification of beta-intercalated cells (approximately 0.20 pH units). The present studies demonstrate the importance of the in vivo acid-base status of the animal in the regulation of CCD HCO3- secretion by beta-intercalated cells. The results identify the possible existence of a previously unrecognized Na(+)-dependent Cl-/HCO3- exchanger on the basolateral membrane of beta-intercalated cells in alkali-loaded rabbits.

Stimulation of chloride transport by HCO3-CO2 in rabbit cortical collecting tubule

1986 ◽  
Vol 251 (1) ◽  
pp. F49-F56 ◽  
Author(s):  
K. Tago ◽  
V. L. Schuster ◽  
J. B. Stokes
Keyword(s):  
Chloride Transport ◽  
Acid Base ◽  
Cl Transport ◽  
Collecting Tubule ◽  
Acid Base Status ◽  
Stimulation Of ◽  
Rabbit Cortical Collecting Tubule ◽  
Cortical Collecting Tubule

We examined both the role of HCO3-CO2 in Cl transport as well as the effect of in vivo acid-base status on Cl transport by the rabbit cortical collecting tubule. The lumen-to-bath 36Cl tracer flux, expressed as the rate coefficient KCl, was measured in either HEPES-buffered (CO2-free) or HCO3-CO2-containing solutions. Amiloride was added to the perfusate to minimize the transepithelial voltage and thus the electrical driving force for Cl diffusion. Because KCl fell spontaneously with time in HCO3-CO2 solutions in the absence but not the presence of cAMP, we used cAMP throughout to avoid time-dependent changes. Acute in vitro removal of bath HCO3-CO2 reduced KCl. Acetazolamide addition in HEPES-buffered solutions also lowered KCl; KCl could be restored to control values by adding exogenous HCO3-CO2 in the presence of acetazolamide. In vivo acid-base effects on Cl transport were determined by dissecting tubules from either NaHCO3-loaded or NH4Cl-loaded rabbits. Tubules from HCO3-loaded rabbits had higher rates of Cl self exchange. Acute in vitro addition of bath HCO3-CO2 increased KCl and did so to a greater degree in tubules from HCO3-loaded rabbits. Most of this effect of HCO3-CO2 addition on KCl could not be accounted for by Cl-HCO3 exchange; rather, it appeared due to stimulation of Cl self exchange. The data are consistent with 36Cl transport occurring via Cl-HCO3 exchange as well as Cl self exchange. Both processes are acutely stimulated by HCO3 and/or Co2, and both are chronically regulated by in vivo acid-base status.

Effect of temperature on intracellular pH in crayfish neurons and muscle fibers

1984 ◽  
Vol 246 (1) ◽  
pp. C45-C49 ◽  
Author(s):  
J. L. Rodeau
Keyword(s):  
Intracellular Ph ◽  
Muscle Fibers ◽  
Effect Of Temperature ◽  
Cellular Regulation ◽  
Acid Base ◽  
Astacus Leptodactylus ◽  
Acid Base Status ◽  
Effects Of Temperature ◽  
Ph Microelectrodes

Intracellular pH microelectrodes were used to determine the effects of temperature (13-26 degrees C) on the in vitro regulation of intracellular acid-base status of neurons and muscle fibers of the crayfish Astacus leptodactylus. The values of the temperature coefficients delta pH/delta T (pH unit/degrees C) were -0.019 and -0.026 for muscles and neurons, respectively, values which are close to the temperature coefficient (-0.019) of the pK' of protein imidazole buffer groups. When temperature varies, the dissociation ratio of imidazole groups is thus maintained by the cellular regulation of cytoplasmic pH. According to the alphastat regulation hypothesis, this constancy would minimize the temperature effects on enzymic systems.

scholarly journals Effect of temperature upon carbon dioxide stores in the snake Coluber constrictor and the turtle Chrysemys scripta

1988 ◽  
Vol 137 (1) ◽  
pp. 529-548 ◽  
Author(s):  
J. N. Stinner ◽  
R. L. Wardle
Keyword(s):  
Body Temperature ◽  
Open Systems ◽  
Effect Of Temperature ◽  
Temperature Plasma ◽  
Coluber Constrictor ◽  
Time Courses ◽  
Lactate Levels ◽  
Transient Elevation

The effect of temperature upon respiratory exchange ratio (R) was measured in snakes (Coluber constrictor) and turtles (Chrysemys scripta). Increasing body temperature produced a transient elevation of R, and lowering body temperature transiently depressed R. These thermal effects resulted from an ‘excess’ and a ‘deficit’ CO2 elimination, respectively. Steady-state blood CO2 content (CCO2) in C. constrictor decreased linearly with rising temperature. Plasma bicarbonate concentration, calculated from in vivo arterial PCO2 and pH, followed the same pattern. Also, time courses of blood CCO2 were consistent with the metabolic studies. Less than half of the change in blood CCO2 could be explained by shifts of the in vitro CO2 dissociation curve; the remainder was contributed by other tissues. Blood lactate levels changed little with temperature. Based upon the blood studies, the predicted quantity of CO2 eliminated from the extracellular space when temperature increases is about 29% of the excess CO2 eliminated from the snakes. Thus, CCO2 in other tissues also decreases with rising temperature. It is concluded that reptiles function as open systems with respect to CCO2, which does not agree with alphastat control. Systemic arterial PO2 and PCO2 increased with rising body temperature in C. constrictor. The mechanisms producing these increases are discussed.

The Effect of Salt Adaptation and Amiloride on the In Vivo Acid-Base Status of the Euryhaline Toad Bufo Viridis

1981 ◽  
Vol 93 (1) ◽  
pp. 93-99
Author(s):  
U. KATZ
Keyword(s):  
Tap Water ◽  
Salt Adaptation ◽  
Acid Base ◽  
Bufo Viridis ◽  
Acid Base Status ◽  
Simultaneous Decrease ◽  
Toad Bufo

1. The acid-base status of the blood of the toad Bufo viridis was studied during adaptation to high salinity and in tap water containing amiloride. 2. Both salt adaptation and immersion for 2-3 days in 5 x10−4 M amiloride in tap water resulted in a decrease in blood pH (from 7.720 ± 0.026 in tap water to 7.456±0.051 in 500 mOsm NaCl-adapted toads; mean ± S.E.), and a simultaneous decrease in the concentration of HCO3- (from 17.8 ±1.4 in tap water to 9.5±1.2 in salt-adapted toads). 3. In vitro determination of Na+/H+ exchange across the skin showed a 1:1 relation in skins from tap-water-adapted toads; this exchange was inhibited by amiloride. H+ secretion was abolished in skins from salt-adapted toads and the uptake of sodium was reduced.

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.

scholarly journals Damage to the gastric epithelium activates cellular bicarbonate secretion via SLC26A9 Cl−/HCO3−exchange

2010 ◽  
Vol 299 (1) ◽  
pp. G255-G264 ◽  
Author(s):  
Elise S. Demitrack ◽  
Manoocher Soleimani ◽  
Marshall H. Montrose
Keyword(s):  
Interstitial Fluid ◽  
Gastric Epithelium ◽  
Acid Base ◽  
Surface Ph ◽  
Two Photon ◽  
Acid Base Status ◽  
Genetic Deletion ◽  
Knockout Animals ◽  
Tissue Compartments

Gastric surface pH (pHo) transiently increases in response to focal epithelial damage. The sources of that increase, either from paracellular leakage of interstitial fluid or transcellular acid/base fluxes, have not been determined. Using in vivo microscopy approaches we measured pHowith Cl-NERF, tissue permeability with intravenous fluorescent-dextrans to label interstitial fluid (paracellular leakage), and gastric epithelial intracellular pH (pHi) with SNARF-5F (cellular acid/base fluxes). In response to two-photon photodamage, we found that cell-impermeant dyes entered damaged cells from luminal or tissue compartments, suggesting a possible slow transcellular, but not paracellular, route for increased permeability after damage. Regarding cytosolic acid/base status, we found that damaged cells acidified (6.63 ± 0.03) after photodamage, compared with healthy surface cells both near (7.12 ± 0.06) and far (7.07 ± 0.04) from damage ( P < 0.05). This damaged cell acidification was further attenuated with 20 μM intravenous EIPA (6.34 ± 0.05, P < 0.05) but unchanged by addition of 0.5 mM luminal H2DIDS (6.64 ± 0.08, P > 0.05). Raising luminal pH did not realkalinize damaged cells, suggesting that the mechanism of acidification is not attributable to leakiness to luminal protons. Inhibition of apical HCO3−secretion with 0.5 mM luminal H2DIDS or genetic deletion of the solute-like carrier 26A9 (SLC26A9) Cl−/HCO3−exchanger blocked the pHoincrease normally observed in control animals but did not compromise repair of damaged tissue. Addition of exogenous PGE2significantly increased pHoin wild-type, but not SLC26A9 knockout, animals, suggesting that prostaglandin-stimulated HCO3−secretion is fully mediated by SLC26A9. We conclude that cellular HCO3−secretion, likely through SLC26A9, is the dominant mechanism whereby surface pH transiently increases in response to photodamage.

Effects of acute temperature change, in vivo and in vitro, on the acid–base status of blood from yellowfin tuna (Thunnus albacares)

1992 ◽  
Vol 70 (4) ◽  
pp. 654-662 ◽  
Author(s):  
Richard W. Brill ◽  
Peter G. Bushnell ◽  
David R. Jones ◽  
Manabu Shimizu
Keyword(s):  
Ion Exchange ◽  
Exchange Rates ◽  
Temperature Change ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Skipjack Tuna ◽  
Acid Base ◽  
System Temperature

In most fishes, blood acid–base regulation following a temperature change involves active adjustments of gill ion-exchange rates which take hours or days to complete. Previous studies have shown that isolated blood from skipjack tuna, Katsuwonus pelamis, and albacore, Thunnus alalunga, had rates of pH change with temperature (in the open system) equivalent to those necessary to retain net protein charge in vivo (≈ −0.016 ΔpH∙ °C−1). It was postulated that this is due to protons leaving the hemoglobin combining with plasma bicarbonate [Formula: see text], which is removed as gaseous CO2, and that this ability evolved so that tunas need not adjust gill ion-exchange rates to regulate blood pH appropriately following ambient temperature changes. We reexamined this phenomenon using blood and separated plasma from yellowfin tuna, Thunnus albacares. Unlike previous studies, our CO2 levels (0.5 and 1.5% CO2) span those seen in yellowfin tuna arterial and venous blood. Various bicarbonate concentrations [Formula: see text] were obtained by collecting blood from fully rested as well as vigorously exercised fish. We use our in vitro data to calculate basic physiochemical parameters for yellowfin tuna blood: nonbicarbonate buffering (β), the apparent first dissociation constant of carbonic acid (pKapp), and CO2 solubility (αCO2). We also determined the effects of acute temperature change on arterial pH, [Formula: see text], and partial pressures of O2 and CO2in vivo. The pH shift of yellowfin tuna blood subjected to a closed-system temperature change did not differ from previous studies of other teleosts (≈ −0.016 ΔpH∙ °C−1). The pH shift in blood subjected to open-system temperature change was Pco2 dependent and lower than that in skipjack tuna or albacore blood in vitro, but identical with that seen in yellowfin tuna blood in vivo. However, pH adjustments in vivo were caused by changes in both [Formula: see text] and Pco2. The exact mechanisms responsible for these changes remain to be elucidated.

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