Temperature-Related Changes in the Erythrocytic Carbonic Anhydrase (Acetazolamide-Sensitive Esterase) Activity of Goldfish, Carassius Auratus

1979 ◽  
Vol 78 (1) ◽  
pp. 255-264
Author(s):  
ARTHUR H. HOUSTON ◽  
KAREN M. MEAROW

1. Carbonic anhydrase activity in ‘membrane’ and ‘cytosol’ fractions of goldfish erythrocytes was assayed by the p-nitrophenyl acetate procedure following thermal acclimation. 2. The thermal sensitivity of ‘membrane’-associated activity was apparently unaltered by acclimation. ‘Cytosol’ activity in warm-acclimated specimens was somewhat more thermosensitive than that of animals maintained at low temperature. 3. Significant increases in specific activity, and activity per unit volume of packed cells and blood were observed at higher temperatures when assays were conducted at the temperatures at which the system actually functions in the fish. By contrast, when determinations were carried out at a standard temperature (41 °C) corresponding to the upper incipient lethal for this species, activity was either unaffected, or declined as acclimation temperatures increased. 4. Changes in carbonic anhydrase activity following acclimation are consistent with the hypothesis that this system is implicated in the maintenance of stable plasma chloride levels, and the suggestion that alterations in red cell chloride levels with temperature are, in part at least, attributable to concomitant variations in enzyme activity.

1981 ◽  
Vol 27 (1) ◽  
pp. 87-92 ◽  
Author(s):  
M. N. MacLeod ◽  
I. W. DeVoe

The carbonic anhydrase activity and the growth of Neisseria sicca 19 were inhibited by the sulfonamide acetazolamide (10−5 M). Such inhibition was completely overcome by the addition of exogenous bicarbonate. Some carbonic anhydrase activity associated with the membranous envelope fraction of the cell was released when cells were broken by sonic treatment but not during cell breakage by high-pressure extrusion. After the selective solubilization (4 °C) of the inner membrane of envelopes by treatment with 1% sodium lauroyl sarcosinate, all detectable carbonic anhydrase activity was found in the soluble (inner membrane) fraction. After fractionation of the cell envelope into inner and outer membranes by treatment with ethylenediaminetetraacetate (EDTA) followed by sucrose density gradient centrifugation, the total and specific activity of carbonic anhydrase paralleled that of succinate dehydrogenase, an inner membrane enzyme marker. The Coomassie blue stained protein patterns after polyacrylamide gel electrophoresis of the bands from the sucrose density gradient provided confirmation that the inner and outer membranes had indeed been separated.


1987 ◽  
Vol 65 (8) ◽  
pp. 1956-1965 ◽  
Author(s):  
Jon Mallatt ◽  
David M. Conley ◽  
Richard L. Ridgway

Two enzymes implicated in branchial ion transport, Na+-K+-ATPase and carbonic anhydrase, were localized in gill ionocytes ("chloride cells") of the Pacific hagfish, Eptatretus stouti, by light microscopic histochemical techniques. In hagfish, ouabain-sensitive Na+-K+-ATPase activity was confined to apical halves of ionocytes, where most of the cytoplasmic tubular system is located. In marine teleosts, Na+-K+-ATPase was noted in chloride cells and erythrocytes. Acetazolamide and potassium cyanate sensitive carbonic anhydrase activity occurred throughout the cytoplasm and nucleus of hagfish ionocytes. Biochemical assay of hagfish gill homogenates for Na+-K+-ATPase yielded a specific activity of 3.1 μmol Pi∙mg protein−1∙h−1 at 37 °C. This resembles values we obtained for freshwater fish (Carassius auratus: 3.3 μmol Pi∙mg protein−1∙h−1; Tilapia shirana: 3.7 μmol Pi∙mg protein−1∙h−1), and is less than values we obtained for marine teleosts (Pomacentrus spp.: 13 μmol Pi∙mg protein−1∙h−1; Gillichthys mirabilis: 6.7 μmol Pi∙mg protein−1∙h−1). Hagfish resemble freshwater teleosts in many other gill features related to ion transport. The presence of carbonic anhydrase in gill ionocytes of hagfish supports the proposal that these cells function in acid–base regulation, i.e., that they exchange H+ for Na+ and [Formula: see text] for Cl−.


1988 ◽  
Vol 66 (3) ◽  
pp. 729-736 ◽  
Author(s):  
A. H. Houston ◽  
A. Murad ◽  
J. D. Gray

Immersion of goldfish, Carassius auratus, in 1 mg∙L−1 phenylhydrazine hydrochloride at 5 °C for 48 h led to reductions of 90–95% in hemoglobin and hematocrit within 10–14 days. Under similar conditions, 96-h exposures prompted heavy mortality. Fewer mortalities occurred after 24-h exposure periods; however, only modest reductions in O2-carrying capacity were seen. All higher concentration (2, 5, 10, 50 mg∙L−1) and temperature (10, 15, 20 °C) combinations led to complete mortality within 12–96 h regardless of exposure period (24, 48, 96 h). Exposure to phenylhydrazine hydrochloride caused decreases in hemoglobin and hematocrit, changes in the abundances of specific hemoglobin isomorphs, and the transient appearance of novel hemoglobin mobilities as well as evidence of osmo- and iono-regulatory dysfunction. Slow warming to 20 °C prompted red cell proliferation and hemoglobin synthesis and restoration of typical hemoglobin isomorph abundances. Incidence of transfer stresses was monitored by reference to differential leucocyte counts. Transfer led to lymphopenia and thrombopenia with neutrophilia and eosinophilia. Warming was accompanied by increases in lymphocyte and thrombocyte counts and reductions in those of monocytes and all granulocytes.


1993 ◽  
Vol 71 (11) ◽  
pp. 2190-2198 ◽  
Author(s):  
Ajmal Murad ◽  
Susan Everill ◽  
Arthur Houston

Erythrocyte division occurs in the blood of goldfish, Carassius auratus L., and is particularly prominent during response to respiratory stresses. The process involves nuclear elongation followed by cellular elongation, central constriction, and attenuation culminating in cell separation. Cytomorphic criteria developed in an earlier study of red cell maturation in this species suggest that the process is restricted to juvenile cells: those possessing the organelles required for hemoglobin synthesis. Consistent with this, but in distinct contrast to mature erythrocytes, dividing cells resemble juvenile cells in their incorporation of 55Fe. This is subsequently detectable by autoradiography in hemoglobin electropherograms. Immuno-fluorescent antibody probes for tubulin and actin revealed an ordered sequence of cytoskeletal changes during the division process. However, the nuclei of dividing cells do not take up [3H]thymidine, and although colchicine and nocodazole treatment led to the appearance of metaphase figures in pronephric and splenic erythroid cells, these were not evident in dividing cells. The nature and possible significance of the process are discussed.


1966 ◽  
Vol 23 (8) ◽  
pp. 1109-1120 ◽  
Author(s):  
Neil Ward Falkner ◽  
A. H. Houston

Red cell numbers and haematocrit values were notable principally for their constancy during a 10-day experimental period following the exposure of goldfish acclimated to 20 C to an abrupt increase of 10 C in environmental temperature. Mean erythrocytic volume underwent a transient decrease while total blood iron (and presumably haemoglobin) and mean erythrocytic iron content fell slightly during the latter portion of the period of observation. Goldfish maintained at 5 C were typically characterized by two haemoglobin polymorphs, a third fraction being commonly found in animals acclimated at 12, 20, and 30 C. The observations are discussed in relation to the respiratory acclimation of this species to increases in environmental temperature.


1995 ◽  
Vol 73 (3) ◽  
pp. 411-418 ◽  
Author(s):  
Arthur H. Houston ◽  
Ajmal Murad

Goldfish (Carassius auratus) were rendered anemic through immersion in phenylhydrazine∙HCl, a cohort of [3H]thymidine-labelled erythrocytes was established, and recovery followed over a 234-d period. Red blood cell (RBC), hemoglobin (Hb), and hematocrit (Hct) levels increased in biphasic fashion during recovery, rapid increases to plateau values being followed by more modest increases to levels equalling those observed prior to treatment. During the initial rapid phase of response, increased ventilatory and cardiovascular activities probably compensated for deficits in oxygen-carrying capacity but, by elevating blood O2 tension, may have suppressed erythropoiesis. Continuing slow increases in RBC, Hb, and Hct may point to some as yet unidentified alternative mechanism for stimulating red cell formation. During maturation, mean erythrocytic volume decreased, while mean erythrocytic hemoglobin level increased. Cycles of division of circulating juvenile erythrocytes occurred at roughly 56-d intervals, but did not appear to play a major role in elevating blood O2-carrying capacity. Division and karyorrhexis or cell breakdown were loosely correlated. Under the conditions employed, red cell half-life was approximately 80 d.


1962 ◽  
Vol 40 (7) ◽  
pp. 1169-1174 ◽  
Author(s):  
Arthur Hillier Houston

Cold death in goldfish acclimated to 20–22 °C and abruptly transferred to temperatures of 2.5–3.5 °C was accompanied by a decrease in plasma chloride concentration, but no marked change in tissue chloride level. While tissue water content remained relatively steady variations in chloride space indicated a progressive shift of fluids from the cellular to the extracellular phase. Although the data indicate some loss of osmoregulatory control during exposure to low temperatures, the variations noted were not considered to be great enough to have alone accounted for the death of the animals.


1981 ◽  
Vol 50 (2) ◽  
pp. 265-271 ◽  
Author(s):  
E. D. Crandall ◽  
A. Bidani

A mathematical model has been used to study the influences of the kinetics of erythrocyte HCO3(-)/Cl-- exchange on CO2 elimination in the lung. In addition to the chloride shift, the model includes 1) CO2-H2CO3 hydration-dehydration reactions in plasma and erythrocytes; 2) CO2 reactions with hemoglobin; 3) O2 binding to hemoglobin; 4)buffering of H+ intra- and extracellularly; 5) red cell volume changes; and 6) diffusion of gases between alveoli and blood. Carbonic anhydrase activity was assumed to be available to plasma as it passes through the lung capillaries. The results show that a reduction of PHCO3(-) leads to a reduction in pulmonary CO2 elimination of up to 30%, whether or not carbonic anhydrase activity is available to plasma. Characteristic slow downstream pH and PCO2 changes predicted for each case may represent an explanation for the apparent discrepancy between in vivo and in vitro slow downstream pH changes reported previously. We conclude that red cell HCO3(-)/Cl- exchange partially limits CO2 elimination from blood in the lung and may have a major influence on capillary gas transfer when its speed is abnormally slow.


1993 ◽  
Vol 175 (1) ◽  
pp. 195-209 ◽  
Author(s):  
M. Huber ◽  
H. Guderley

To examine whether the changes in metabolic organization induced by thermal acclimation modify glycolytic enzyme-binding, we acclimated goldfish, Carassius auratus, to 8 and 25 °C and measured the binding of phosphofructokinase (PFK), aldolase, pyruvate kinase and lactate dehydrogenase to subcellular particles in red and white muscle. When fish were sampled at rest at their acclimation temperature, only the percentage binding of PFK in red muscle was altered by thermal acclimation. By contrast, exhausting exercise at 15 sC led to markedly higher levels of binding of PFK in muscle of warm- than of cold-acclimated fish. This pattern was apparent in both red and white muscle. The specific activity of PFK in red muscle declined with exhausting exercise in warm- but not in cold-acclimated fish. In contrast, the units of PFK bound per gram of muscle did not differ in exhausted warm- and cold-acclimated fish. Cold- and warm-acclimated fish did not differ in their accumulation of lactate in white muscle at exhaustion. Furthermore, the PFK from white muscle of warm- and cold-acclimated fish did not differ in the pH dependence of binding to subcellular particles. These changes in the dynamics of PFK binding with temperature acclimation suggest that soluble PFK may be more susceptible to exercise-induced inhibition in warm- than in cold-acclimated goldfish. While the percentage binding and the specific activity of the other glycolytic enzymes were little affected by exhausting exercise, the units of aldolase bound per gram of white muscle decreased with exercise in warm-acclimated fish.


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