scholarly journals LOCALIZATION OF CARBONIC ANHYDRASE ACTIVITY IN TURTLE AND TOAD URINARY BLADDER MUCOSA

1972 ◽  
Vol 20 (9) ◽  
pp. 696-702 ◽  
Author(s):  
SEYMOUR ROSEN
Keyword(s):  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Activity ◽  
Cobalt Sulfide ◽  
Toad Urinary Bladder ◽  
Staining Reaction ◽  
Luminal Surface ◽  
Electron Microscopic ◽  
Turtle Bladder ◽  
Mucosal Cells ◽  
Sulfide Compound

Carbonic anhydrase activity was demonstrated in a distinct population of mucosal cells of whole stretched bladder of turtle and toad. The apical portions of the cells containing the enzyme were discretely stained as noncontiguous polygonal forms and allowed an estimation of the luminal surface representation of this epithelium. The slight luminal surface (0.8% or less) occupied by cells with carbonic anhydrase activity in the toad bladder contrasted with a greater representation in turtle bladder (6.4-12.2%) and correlated with the relative capacity of these tissues to acidify. After completion of the enzyme staining reaction the tissues of the turtle bladder were directly processed for electron microscopic observations without osmium tetroxide postfixation. The deposition of the electron-opaque cobalt sulfide compound was selective and was found only in cells with luminal representation and small apical granules, the recently described "third cell type"; cobalt sulfide was mainly present in the cytoplasm, an observation consonant with the known localization of carbonic anhydrase primarily in supernatant fractions.

scholarly journals Carbonic anhydrase, ultrastructural localization in the mouse gastric mucosa and improvements in the technique.

1980 ◽  
Vol 28 (6) ◽  
pp. 511-525 ◽  
Author(s):  
N Sugai ◽  
S Ito
Keyword(s):  
Electron Microscopy ◽  
Gastric Mucosa ◽  
Carbonic Anhydrase ◽  
Picric Acid ◽  
Ultrastructural Localization ◽  
Carbonic Anhydrase Activity ◽  
Cobalt Sulfide ◽  
Ultrastructural Studies ◽  
Mucosal Cells ◽  
Erythrocyte Carbonic Anhydrase

The ultrastructural localization of carbonic anhydrase activity in mouse gastric mucosal cells as revealed by the cobalt bicarbonate histochemical method of Hansson has been made. In addition the effects of fixatives used for ultrastructural studies have been evaluated for reduction of carbonic anhydrase activity; exogenous erythrocyte carbonic anhydrase has been localized in tissues; acetazolamide and potassium cyanate inhibition of activity demonstrated; and an improved method for the osmication of reacted tissues for electron microscopy has been developed. The results indicate that the glutaraldehyde, formaldehyde, picric acid fixative, which retains about 5% of the original carbonic anhydrase activity, is distinctly better for histochemical studies than formaldehyde fixation, which retains about 32% activity. Acetazolamide at 10(-5) M consistently inhibits histochemical reaction, as does 20 mM KCNO, in the incubation medium. Exogenous carbonic anhydrase is readily visualized by the histochemical technique. Electron microscopy of gastric mucosa reacted for carbonic anhydrase activity indicates the focal deposition of the cobalt sulfide reaction product in the cores of microvilli lining the intracellular canaliculi, in the basal and lateral cell folds of parietal cells, and in the microvilli as well as the cytoplasm between mucous granules in the surface mucous cells. In addition, some reaction product was found in the mitochondrial cristae and in some nuclei and intercellular spaces.

scholarly journals Ultrastructural localization of exogenous carbonic anhydrase activity in ileal absorptive cells of suckling rats.

1980 ◽  
Vol 28 (6) ◽  
pp. 563-569 ◽  
Author(s):  
N Sugai ◽  
S Ito
Keyword(s):  
Carbonic Anhydrase ◽  
Ultrastructural Localization ◽  
Carbonic Anhydrase Activity ◽  
Electron Microscopic Level ◽  
Cobalt Sulfide ◽  
Histochemical Reaction ◽  
Histochemical Technique ◽  
Electron Microscopic ◽  
Absorptive Cells ◽  
Different Types

To test the resolution and reliability of Hansson's histochemical reaction for carbonic anhydrase (CAH) activity at the electron microscopic level, purified exogenous bovine, rabbit, and human B and C CAH was reacted for histochemical activity after uptake by suckling rat ileal absorptive cells and examined microscopically. The cobalt sulfide reaction product was found confined to the apical vacuoles, tubules, and vesicles as small as 30 nm in diameter and was confined within the limiting membrane of the endocytic system. The histochemical technique did not distinguish between the different types or sources of the CAH nor were differences in their enzymatic activity apparent. It was concluded that when the cobalt precipitation technique of Hansson is used to demonstrate exogenous CAH activity it results in the precipitation of the reaction product at or very near the site of the CAH molecule. In addition to the resolution of the technique to demonstrate enzyme activity, this study suggests that the ultrastructural localization of intrinsic CAH activity can be accepted with greater confidence.

Carbonic anhydrase activity and aminopyrine uptake in isolated gastric mucosal cells

1984 ◽  
Vol 247 (3) ◽  
pp. G213-G219
Author(s):  
A. Wollin
Keyword(s):  
Carbonic Anhydrase ◽  
Acid Secretion ◽  
Carbonic Anhydrase Activity ◽  
Isolated Cells ◽  
Oxyntic Cell ◽  
Mucosal Cells ◽  
Cell Fractions ◽  
Isolated Cell

The role of carbonic anhydrase in the regulation and production of gastric acid was examined. Studies were done on isolated rabbit fundic mucosal cells, in which carbonic anhydrase activity and [14C]aminopyrine uptake were measured. The oxyntic cell-enriched cell fractions had the largest carbonic anhydrase content (4.2 +/- 0.1 U/10(6) cells) compared with other mucosal cells. The cellular carbonic anhydrase content of all isolated cell fractions was primarily a soluble enzyme, accounting for 10% of the total mucosal enzyme quantity. The remainder was found in the incubation medium from the mucosal dispersion procedure. The remaining cellular carbonic anhydrase activity in the oxyntic cell fraction was not enhanced by secretagogues. [14C]aminopyrine uptake increased dose dependently in the presence of histamine and dibutyryl cAMP. Acetazolamide (0.2 mM) inhibited the cellular carbonic anhydrase activity (99%) but did not interfere with the cellular uptake of [14C]aminopyrine. The present data from isolated cells suggest that cellular carbonic anhydrase in the oxyntic cell does not appear to be an integral step in the initiation of secretory function of isolated oxyntic cells. The lack of interference by the carbonic anhydrase inhibitor with H+ production does not exclude a role for carbonic anhydrase at high levels of acid secretion as it may occur in vivo, since isolated oxyntic cells probably do not achieve maximal rates of acid secretion and aminopyrine uptake reflects acid gradients and not rate of acid secretion.

Transport and histochemical studies of bicarbonate handling by the alligator kidney

1989 ◽  
Vol 256 (2) ◽  
pp. F239-F245 ◽  
Author(s):  
S. C. Ventura ◽  
T. E. Northrup ◽  
G. Schneider ◽  
J. J. Cohen ◽  
S. Garella
Keyword(s):  
Carbonic Anhydrase ◽  
Proximal Tubule ◽  
Collecting Duct ◽  
Distal Tubule ◽  
Carbonic Anhydrase Activity ◽  
Tubular Secretion ◽  
Ammonium Bicarbonate ◽  
Cobalt Sulfide ◽  
Orange Fluorescence ◽  
Collecting Duct Cells

The alligator excretes a persistently alkaline urine despite consuming an acid-residue diet. The amount of bicarbonate excreted is greater than the amount filtered, evidencing tubular secretion of bicarbonate. The parallel urinary excretion of ammonium maintains external acid balance. To investigate putative renal mechanisms responsible for the concurrent excretion of large quantities of ammonium bicarbonate, we used acridine orange fluorescence methodology in microvesicles prepared from the proximal tubule brush border to assess the activity of the Na+-H+ antiporter, and histochemical methods (cobalt sulfide precipitation) to assess carbonic anhydrase localization. We found no evidence for the presence of a functioning Na+-H+ antiporter, the protein known to be responsible for the majority of bicarbonate reabsorption in mammals; Na+-H+ exchange in vesicles from the alligator kidney failed to exhibit saturation kinetics, showed no affinity for lithium, and was not inhibited by amiloride. Sensitive histochemical techniques failed to reveal carbonic anhydrase activity anywhere in the proximal tubule but detected an abundance of enzyme activity in the basolateral membranes and nuclei of distal tubular cells. In the connecting segment and collecting duct, cells without carbonic anhydrase alternated with cells containing carbonic anhydrase; in the latter, the enzyme was localized to the basolateral and luminal membranes, the nucleus and, to a lesser extent, throughout the cytoplasm. We conclude that the proximal tubule of the alligator kidney is devoid of the machinery necessary for the transport of large amounts of bicarbonate. The principal site at which bicarbonate is added to the final urine appears to be the distal tubule, at which site carbonic anhydrase is widespread.

Silver Staining of Pancreatic Islets as Revealed by Electron Microscopy

1967 ◽  
Vol 25 ◽  
pp. 44-45
Author(s):  
Kazuaki Misugi ◽  
Nobuko Misugi ◽  
Hiroshi Yamada
Keyword(s):  
Pancreatic Islet ◽  
Silver Staining ◽  
Islet Cells ◽  
Severe Hypoglycemia ◽  
Granular Cell ◽  
Electron Microscopic Level ◽  
Staining Reaction ◽  
Electron Microscopic ◽  
Pancreatic Islet Cell ◽  
D Cell

The authors had described the fine structure of a type of pancreatic islet cell, which appeared different from typical alpha and beta cells, and tentatively considered that this third type of granular cell probably represents the D cell (Figure 1).Since silver staining has been widely used to differentiate different types of pancreatic islet cells by light microscopy, an attempt to examine this staining reaction at the electron microscopic level was made.Material and Method: Surgically removed specimens from three infants who suffered from severe hypoglycemia were used. The specimens were fixed and preserved in 20% neutral formalin. Frozen sections, 30 to 40 micron thick, were prepared and they were stained by Bielschowsky's method as modified by Suzuki (2). The stained sections were examined under a microscope and islet tissues were isolated. They were fixed in 1% osmium tetroxide in phosphate buffer for one hour and embedded in Epon 812 following dehydration through a series of alcohols and propylene oxide.

1123: Renal Oxalate Transport Depends on Local Carbonic Anhydrase Activity in the Proximal Tubule

2004 ◽  
Vol 171 (4S) ◽  
pp. 296-296
Author(s):  
Michael Straub ◽  
Joséphine Befolo-Elo ◽  
Richard E Hautmann ◽  
Edgar Braendle
Keyword(s):  
Carbonic Anhydrase ◽  
Proximal Tubule ◽  
Carbonic Anhydrase Activity ◽  
Oxalate Transport

scholarly journals Immunocytochemical localization of mitochondrial carbonic anhydrase in rat tissues.

1991 ◽  
Vol 39 (4) ◽  
pp. 451-459 ◽  
Author(s):  
H K Väänänen ◽  
N D Carter ◽  
S J Dodgson
Keyword(s):  
Skeletal Muscle ◽  
Carbonic Anhydrase ◽  
Cardiac Tissue ◽  
Polyclonal Antiserum ◽  
Heterogeneous Population ◽  
Rat Tissues ◽  
Staining Reaction ◽  
Gastric Parietal Cells ◽  
First Time ◽  
Carbonic Anhydrase Gene

We used a monospecific polyclonal antiserum against mitochondrial carbonic anhydrase (CA V) from rat liver to study tissue localization of this new member of the carbonic anhydrase gene family. Strong granular immunostaining reaction of CA V was observed in hepatocytes, myocardium, and in certain populations of skeletal muscle fibers. This is the first time that mitochondrial carbonic anhydrase is described in cardiac tissue of rat or any other species. Different epithelial cells revealed very heterogeneous staining reaction, suggesting that mitochondria are a heterogeneous population with respect to their CA V content. Many cells in different glandular epithelia did not show any CA V, whereas some cells, such as gastric parietal cells, were intensely stained with CA V antibodies. No systematic co-expression of CA V with CA I, CA II, or CA III was observed, although the distribution of CA V in skeletal muscle was somewhat similar to that of CA III. Connective tissue cells such as fibroblasts, chondroblasts, and osteoblasts were negative.

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