Mechanism of acid adaptation of a fish living in a pH 3.5 lake

2003 ◽  
Vol 284 (5) ◽  
pp. R1199-R1212 ◽  
Author(s):  
Taku Hirata ◽  
Toyoji Kaneko ◽  
Toshihiro Ono ◽  
Takeru Nakazato ◽  
Norihisa Furukawa ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Basolateral Membrane ◽  
Single Species ◽  
Carbonic Anhydrase Ii ◽  
Chloride Cells ◽  
Apical Surface ◽  
Acidic Lake ◽  
Apical Side ◽  
High Concentrations

Despite unfavorable conditions, a single species of fish, Osorezan dace, lives in an extremely acidic lake (pH 3.5) in Osorezan, Aomori, Japan. Physiological studies have established that this fish is able to prevent acidification of its plasma and loss of Na+. Here we show that these abilities are mainly attributable to the chloride cells of the gill, which are arranged in a follicular structure and contain high concentrations of Na+-K+-ATPase, carbonic anhydrase II, type 3 Na+/H+ exchanger (NHE3), type 1 Na+-HCO[Formula: see text] cotransporter, and aquaporin-3, all of which are upregulated on acidification. Immunohistochemistry established their chloride cell localization, with NHE3 at the apical surface and the others localized to the basolateral membrane. These results suggest a mechanism by which Osorezan dace adapts to its acidic environment. Most likely, NHE3 on the apical side excretes H+ in exchange for Na+, whereas the electrogenic type 1 Na+-HCO[Formula: see text]cotransporter in the basolateral membrane provides HCO[Formula: see text] for neutralization of plasma using the driving force generated by Na+-K+-ATPase and carbonic anhydrase II. Increased expression of glutamate dehydrogenase was also observed in various tissues of acid-adapted dace, suggesting a significant role of ammonia and bicarbonate generated by glutamine catabolism.

Prevalence of Autoantibodies to Carbonic Anhydrase II and Lactoferrin in Patients with Type 1 Diabetes

2004 ◽  
Vol 1037 (1) ◽  
pp. 131-132 ◽  
Author(s):  
ENRICO CESARE ◽  
MARCELLO PREVITI ◽  
FORTUNATO LOMBARDO ◽  
NICOLA MAZZÙ ◽  
ANTONINO BENEDETTO ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Ii

scholarly journals Carbonic anhydrase in human platelets

1984 ◽  
Vol 217 (3) ◽  
pp. 727-730 ◽  
Author(s):  
W Siffert ◽  
G Gros
Keyword(s):  
Carbonic Anhydrase ◽  
Carbonic Anhydrase Activity ◽  
Human Platelets ◽  
Carbonic Anhydrase Ii ◽  
Affinity Column ◽  
Kinetic Properties ◽  
Km Value ◽  
Flow Apparatus ◽  
High Concentrations ◽  
Kinetics Of

The carbonic anhydrase activity of human platelets was investigated by measuring the kinetics of CO2 hydration in supernatants of platelet lysates by using a pH stopped-flow apparatus. An average carbonic anhydrase concentration of 2.1 microM was determined for pellets of human platelets. Analysis of the kinetic properties of this carbonic anhydrase yielded a Km value of 1.0 mM, a catalytic-centre activity kcat. of 130000 s-1 and an inhibition constant Ki towards ethoxzolamide of 0.3 nM. From these values, CO2 hydration inside platelets is estimated to be accelerated by a factor of 2500. When platelet lysates were subjected to affinity chromatography, only the high-activity carbonic anhydrase II could be eluted from the affinity column, whereas the carbonic anhydrase isoenzyme I, which is known to occur in high concentrations in human erythrocytes, appeared to be absent.

Ion-secreting epithelia: chloride cells in the head region of Fundulus heteroclitus

1980 ◽  
Vol 238 (3) ◽  
pp. R185-R198 ◽  
Author(s):  
K. J. Karnaky
Keyword(s):  
Fundulus Heteroclitus ◽  
Chloride Transport ◽  
Basolateral Membrane ◽  
Freeze Fracture ◽  
Chloride Ion ◽  
Salt Gland ◽  
Chloride Cells ◽  
Head Region ◽  
Zonulae Occludentes ◽  
Apical Side

Transporting cells of ion-secreting epithelia are characterized by similar morphological patterns that include rich supplies of mitochondria, exotic patterns of surface amplification, and basolateral, plasma-membrane location of Na-K-ATPase, even though the direction of sodium transport across these epithelia is toward the apical side. Several new models for NaCl secretion propose that sodium, extruded into the intercellular space by Na-K-ATPase, reaches the apical side via the zonulae occludentes. Very recent freeze-fracture electron microscopy of avian salt gland and teleost chloride cells reveals that transporting cells are joined by simple, shallow zonulae occludentes. These observations lend morphological support to the concept that paracellular sodium ion permeation plays a central role in secretion. The chloride ion may traverse the epithelium via a transcellular route, entering the cell at the basolateral membrane by a chloride carrier linked to the cotransport of sodium down its electrochemical gradient into the cell. Finally, the chloride ion may exit the cell across the apical membrane by electrical forces. This review summarizes biochemical, morphological, and electrophysiological aspects of these new secretory models and the important contribution of a half century of research on teleost osmoregulatory mechanisms, including the chloride cell, to our understanding of sodium and chloride transport across secretory epithelia.

scholarly journals A novel juxtamembrane basolateral targeting motif regulates TGF-β receptor signaling in Drosophila

2020 ◽  
Author(s):  
Aidan J. Peterson ◽  
Stephen J. Murphy ◽  
Melinda G. Mundt ◽  
Maryjane Shimell ◽  
Edward B. Leof ◽  
...  
Keyword(s):  
Mdck Cells ◽  
Basolateral Membrane ◽  
Wing Disc ◽  
Female Sterility ◽  
Epithelial Tissue ◽  
Type I ◽  
Apical Surface ◽  
Type Ii ◽  
Apical Side ◽  
Basolateral Targeting

AbstractIn polarized epithelial cells, receptor-ligand interactions can be restricted by different spatial distributions of the two interacting components giving rise to an underappreciated layer of regulatory complexity. We explored whether such regulation occurs in the Drosophila wing disc, an epithelial tissue that requires the TGF-β family member Dpp for growth and patterning. Dpp protein has been observed in a gradient within the columnar cells of the disc, but also uniformly in the disc lumen leading to the question of how graded signaling is achieved in the face of two distinctly localized pools. We find the Dpp type II receptor Punt, but not the type I receptor Tkv, is enriched at the basolateral membrane, and depleted at the junctions and apical surface. Wit, a second type II receptor, shows a markedly different behavior, with the protein detected on all membrane regions but enriched at the apical side. Mutational studies enabled us to identify the BLT, a novel, short juxtamenbrane sequence that confers basolateral targeting of Punt in both wing discs and mammalian MDCK cells. Rescue of punt mutants with transgenes altered in the targeting motif showed that flies expressing apicalized Punt due to the lack of a functional BLT displayed developmental defects, female sterility and significant lethality. We also show that apicalized Punt does not produce an ectopic signal, indicating that the apical pool of Dpp is not a significant signaling source even when presented with Punt. Finally, we present evidence that the BLT acts through polarized sorting machinery that differs between types of epithelia. This suggests a code whereby each epithelial cell type may differentially traffic common receptors to enable distinctive responses to spatially localized pools of extracellular ligands.

Asymmetric distribution of muscarinic acetylcholine receptors in Madin-Darby canine kidney cells

1999 ◽  
Vol 277 (6) ◽  
pp. C1220-C1228 ◽  
Author(s):  
Laurie S. Nadler ◽  
Geetha Kumar ◽  
Thomas R. Hinds ◽  
Jacques C. Migeon ◽  
Neil M. Nathanson
Keyword(s):  
Basolateral Membrane ◽  
Muscarinic Acetylcholine Receptors ◽  
Asymmetric Distribution ◽  
Apical Surface ◽  
Binding Studies ◽  
Madin Darby Canine Kidney ◽  
Apical Side ◽  
Basolateral Side ◽  
Darby Canine Kidney ◽  
Canine Kidney

We have characterized the muscarinic ACh receptors (mAChRs) expressed in Madin- Darby canine kidney (MDCK) strain II epithelial cells. Binding studies with the membrane-impermeable antagonist N-[3H]methylscopolamine demonstrated that mAChRs are ∼2.5 times more abundant on the basolateral than on the apical surface. Apical, but not basolateral, mAChRs inhibited forskolin-stimulated adenylyl cyclase activity in response to the agonist carbachol. Neither apical nor basolateral mAChRs exhibited detectable carbachol-stimulated phospholipase C activity. Carbachol application to the apical or the basolateral membrane resulted in a threefold increase in intracellular Ca2+ concentration, which was completely inhibited by pertussis toxin on the apical side and partially inhibited on the basolateral side. RT-PCR analysis showed that MDCK cells express the M4 and M5 receptor mRNAs. These data suggest that M4 receptors reside on the apical and basolateral membranes of polarized MDCK strain II cells and that the M5 receptor may reside in the basolateral membrane of a subset of cells.

Inhibition Profiling of Urease and Carbonic Anhydrase II by High- Throughput Screening and Molecular Docking Studies of Structurally Diverse Organic Compounds

2020 ◽  
Vol 17 ◽  
Author(s):  
Majid Ali ◽  
Syed Majid Bukhari ◽  
Asma Zaidi ◽  
Farhan A. Khan ◽  
Umer Rashid ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Carbonic Anhydrase ◽  
Metal Complexes ◽  
Organic Compounds ◽  
High Throughput ◽  
High Throughput Screening ◽  
Docking Studies ◽  
Carbonic Anhydrase Ii ◽  
Molecular Docking Studies ◽  
Ic50 Values

Background:: Structurally diverse organic compounds and available drugs were screened against urease and carbonic anhydrase II in a formulation acceptable for high-throughput screening. Objective: The study was conducted to find out potential inhibitors of urease and carbonic anhydrase II. Methods:: Quantification of the possible HITs was carried out by determining their IC50 values. Results and Discussion:: of several screened compounds including derivatives of oxadiazole, coumarins, chromane-2, 4- diones and metal complexes of cysteine-omeprazole showed promising inhibitory activities with IC50 ranging from 47 μM to 412 μM against the urease. The interactions of active compounds with active sites of enzymes were investigated through molecular docking studies which revealed that (R)-1-(4-amino-4-(5-(thiophen-2-yl)-1,3,4-oxadiazol-2-yl) butyl) guanidine possessing IC50 of 47 μM, interacts with one of the nickel metal atom of urease besides further interactions as predictable hydrogen bonds with KCX490, Asp633, His492, His407 and His409 along with Ala440 and 636. Bi-ligand metal complexes of 4-aminoantipyrine based Schiff bases showed activation of urease with AC50 ranging from 68 μM to 112 μM. Almost 21 compounds with varying functional groups including pyrimidines, oxadiazoles, imidazoles, hydrazides and tin based compounds were active carbonic anhydrase II inhibitors presenting 98 μM to 390 μM IC50 values. Several N-substituted sulfonamide derivatives were inactive against carbonic anhydrase II. Conclusion:: Among all the screened compounds, highly active inhibitor of carbonic anhydrase II was (4-(3- hydroxyphenyl)-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)phenyl) methanone with IC50 of 98.0 μM. This particular compound showed metallic interaction with Zn ion of carbonic anhydrase II through hydroxyl group of phenyl ring.

Sign in / Sign up

Export Citation Format

Share Document