Acid release in cultured gas gland cells

1999 ◽  
Vol 124 ◽  
pp. S37
Author(s):  
B Pelster ◽  
H Niederstätter
Keyword(s):  
Gland Cells ◽  
Acid Release ◽  
Gas Gland

Mechanisms of acid release in isolated gas gland cells of the European eel Anguilla anguilla

1995 ◽  
Vol 269 (4) ◽  
pp. R793-R799 ◽  
Author(s):  
B. Pelster
Keyword(s):  
Carbonic Anhydrase ◽  
Disulfonic Acid ◽  
European Eel ◽  
Proton Release ◽  
Isolated Cells ◽  
Extracellular Medium ◽  
Proton Secretion ◽  
Gland Cells ◽  
Acid Release ◽  
Gas Gland

Mechanisms of acid production and of acid release have been analyzed in isolated gas gland cells of the eel swimbladder using a cytosensor microphysiometer. Incubation of isolated cells with oxamic acid caused a dose-dependent decrease in the rate of proton release. At the highest oxamic acid concentration used (20 mmol/l), proton release was reduced by approximately 40%; incubation with sodium fluoride (10 mmol/l) or removal of glucose from the extracellular medium caused 60 and 80% reduction, respectively. NaCN had little effect on proton secretion. Proton release of isolated gas gland cells was largely dependent on the extracellular sodium concentration, and this sodium effect was in part inhibitable by amiloride. A 15-20% reduction in the rate of proton secretion was observed in the presence of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, an inhibitor of anion exchange. Inhibition of mammalian H(+)-K(+)-adenosinetriphosphatase with omeprazole had no effect, whereas bafilomycin, an inhibitor of vesicular H(+)-adenosinetriphosphatase, induced a 25% reduction in proton secretion. Ethoxzolamide, a membrane-permeable inhibitor of carbonic anhydrase, caused a 60% reduction in proton secretion (inhibition constant = 54.4 nmol/l). Prontosil-dextran, a membrane-impermeable sulfonamide, also reduced the proton release, thus indicating the presence of a membrane-bound carbonic anhydrase facing the extracellular space.

pH-dependent proton secretion in cultured swim bladder gas gland cells

1997 ◽  
Vol 273 (5) ◽  
pp. R1719-R1725 ◽  
Author(s):  
B. Pelster ◽  
H. Niederstätter
Keyword(s):  
Acid Production ◽  
Ph Dependence ◽  
Low Ph ◽  
Swim Bladder ◽  
Proton Secretion ◽  
Gland Cells ◽  
Sodium Dependent ◽  
Acid Release ◽  
Decreasing Ph ◽  
Gas Gland

The pH dependence of acid production and of acid release has been analyzed in cultured gas gland cells of the European eel using a cytosensor microphysiometer. Total acid release of gas gland cells showed an optimum at pH 7.4–7.6, with only a minor reduction at acidic (pH 7.0) as well as at alkaline pH (pH 8.0). The acid production was largely dependent on the availability of extracellular glucose and was almost completely abolished if glucose was replaced by succinate, alanine, or even pyruvate. Phloretin, an inhibitor of glucose uptake, significantly reduced acid release of gas gland cells with a K i of ∼1 × 10−5 M, irrespective of pH. Although the glucose dependence of acid production was not modified by pH, acid release became increasingly sodium dependent with decreasing pH, but at low pH significantly higher sodium concentrations were necessary to achieve maximal rate of proton secretion. This sodium-dependent proton secretion could only in part be inhibited by application of 5-( N-methyl- N-isobutyl)-amiloride. Removal of extracellular potassium caused a slow reduction in the rate of acid secretion. A similar reduction was observed in the presence of ouabain, a specific inhibitor of Na+-K+-adenosinetriphosphatase, and both effects significantly increased with decreasing pH. The results demonstrate a significant pH dependence of the mechanisms of acid release in swim bladder gas gland cells and indicate that sodium-dependent pathways become especially important at low pH.

Control of acid secretion in cultured gas gland cells of the European eel Anguilla anguilla

1996 ◽  
Vol 270 (3) ◽  
pp. R578-R584
Author(s):  
B. Pelster ◽  
L. Pott
Keyword(s):  
Acid Secretion ◽  
Primary Culture ◽  
Single Cells ◽  
Calf Serum ◽  
Anguilla Anguilla ◽  
Beta Agonist ◽  
European Eel ◽  
Adrenergic Stimulation ◽  
Gland Cells ◽  
Gas Gland

Single cells and cell clusters isolated from the swimbladder epithelium of the European eel Anguilla anguilla attached to collagen S-coated petri dishes and proliferated in a modified Dulbecco's modified Eagle's medium, supplemented with 0.5% fetal calf serum. At a temperature of 20-22 degrees C, the growing colonies reached confluence typically within 6-8 days. Activities of glycolytic and pentose phosphate shunt enzymes remained stable or increased only slightly during the first 10 days of primary culture. Incubated in a defined medium providing glucose as a fuel, gas gland cells in primary culture produced and released lactic acid. The rate of acid secretion of cultured gas gland cells measured with a cytosensor microphysiometer was not influenced by cholinergic stimulation. Similarly, the Ca2+ ionophore A-23187 had no effect. Adrenergic stimulation with epinephrine or the beta-agonist isoproterenol also did not increase the rate of acid secretion, indicating that in gas gland cells the metabolic activity cannot be stimulated via beta-adrenergic stimulation followed by an increase in adenosine 3',5'-cyclic monophosphate (cAMP). Artificially increasing the intracellular concentration of cAMP by incubation with forskolin or the cAMP analogue 8-(4-chlorophenylthio)-cAMP even resulted in a marked reduction in the rate of acid secretion. The results demonstrate that primary cell culture provides a useful means for the analysis of metabolic control and of ion transfer processes in swimbladder gas gland cells.

scholarly journals Swimming under elevated hydrostatic pressure increases glycolytic activity in gas gland cells of the European eel

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0239627
Author(s):  
Gabriel Schneebauer ◽  
Constantin Lindemann ◽  
Victoria Drechsel ◽  
Lasse Marohn ◽  
Klaus Wysujack ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
European Eel ◽  
Gland Cells ◽  
Elevated Hydrostatic Pressure ◽  
Glycolytic Activity ◽  
Gas Gland

Swim bladder gas gland cells produce surfactant: in vivo and in culture

2000 ◽  
Vol 279 (6) ◽  
pp. R2336-R2343 ◽  
Author(s):  
C. Prem ◽  
W. Salvenmoser ◽  
J. Würtz ◽  
B. Pelster
Keyword(s):  
Surfactant Protein ◽  
Cross Reaction ◽  
Tissue Homogenate ◽  
European Eel ◽  
Microscopical Examination ◽  
Swim Bladder ◽  
Lamellar Bodies ◽  
Bladder Tissue ◽  
Gland Cells ◽  
Gas Gland

Electron microscopical examination of gas gland cells of the physostome European eel ( Anguilla anguilla) and of the physoclist perch ( Perca fluviatilis) revealed the presence of significant numbers of lamellar bodies, which are known to be involved in surfactant secretion. In the perch, in which the gas gland is a compact structure and gas gland cells are connected to the swim bladder lumen via small canals, lamellar bodies were also found in flattened cells forming the swim bladder epithelium. Flat epithelial cells are absent in the eel swim bladder, in which the whole epithelium consists of cuboidal gas gland cells. In both species, Western blot analysis using specific antibodies to human surfactant protein A (SP-A) showed a cross-reaction with swim bladder tissue homogenate proteins of ∼65 kDa and in the eel occasionally of ∼120 kDa, probably representing SP-A-like proteins in a dimeric and a tetrameric state. An additional band was observed at ∼45 kDa. Western blots using antibodies to rat SP-D again resulted in a single band at ∼45 kDa in both species, suggesting that there might be a cross-reaction of the antibody to human SP-A with an SP-D-like protein of the swim bladder tissue. To localize the surfactant protein, eel gas gland cells were cultured on permeable supports. Under these conditions, the gas gland cells regain their characteristic polarity. Electron microscopy confirmed the presence of lamellar bodies in cultured cells, and occasionally, exocytotic events were observed. Immunohistochemical staining using an antibody to human SP-A demonstrated the presence of surfactant protein only in luminal membranes and in adjacent lateral membranes. Only occasionally, evidence was found for the presence of surfactant protein in lamellar bodies.

Infection of the glass-eel swimbladder with the nematode Anguillicola crassus

Parasitology ◽  
2000 ◽  
Vol 121 (1) ◽  
pp. 75-83 ◽  
Author(s):  
K. NIMETH ◽  
P. ZWERGER ◽  
J. WÜRTZ ◽  
W. SALVENMOSER ◽  
B. PELSTER
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Swimming Activity ◽  
Microscopical Examination ◽  
Critical Swimming Speed ◽  
Glass Eel ◽  
Gland Cells ◽  
Anguillicola Crassus ◽  
Glass Eels ◽  
Gas Gland

The ability of the nematode Anguillicola crassus to infect eel larvae (glass-eel stage) was tested. The results show that glass-eels fed on infected copepods, the natural intermediate host of the nematode, can be infected. Light microscopical examination of the infected developing swimbladder tissue revealed that the infection results in a significant thickening of the connective tissue. The basolateral labyrinth of gas gland cells is very much reduced in infected swimbladders, and the distance of gas gland cells to blood capillaries is enlarged. Critical swimming speed, defined as the speed where the larvae were no longer able to swim against the current, was similar in infected and uninfected animals. At intermediate speeds (about 60–80% of critical swimming speed) infected eels showed a slightly higher swimming activity than control animals. Resting oxygen consumption, measured as an index of metabolic activity, within the first 2 months of infection was higher in control animals, which may be due to a reduced rate of activity in infected glass-eels. By 4–5 months after the infection, however, it was significantly higher in infected animals. This may indicate that at this stage a higher activity of the animals is required to compensate for the increase in body density, but swimming performance of infected and non-infected glass-eels was not significantly different. Oxygen consumption during swimming activity, measured in a swim tunnel at 50% of maximal swimming speed, also was not affected. The results thus show that even glass-eels can be infected with A. crassus, and this probably contributes to the rapid spread of the nematode in Europe. While aerobic metabolism during swimming activity is not affected at this stage of infection, the swimbladder tissue shows severe histological changes, which most likely will impair swimbladder function.

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