Carbonic anhydrase activity of rabbit lungs

1980 ◽  
Vol 49 (4) ◽  
pp. 589-600 ◽  
Author(s):  
R. M. Effros ◽  
L. Shapiro ◽  
P. Silverman
Keyword(s):  
Carbonic Anhydrase ◽  
Pulmonary Artery ◽  
Extravascular Lung Water ◽  
Carbonic Anhydrase Activity ◽  
Co2 Exchange ◽  
Tissue Binding ◽  
Lung Water ◽  
Expired Gas

Pulmonary carbonic anhydrase (CA) activity was studied in rabbit lungs perfused with solutions containing no CA. Measurements were made of the amount of 14CO2 appearing in the expired gas following injections of H14CO3(-), 14CO2, or a 20:1 mixture of each into the pulmonary artery. The fraction of the injected label in the expired gas was only 17% greater for 14CO2 than for the mixture, suggesting that equilibration between H14CO3(-) and 14CO2 was nearly complete during the capillary transit time. Inhibition of pulmonary CA decreased excretion of H14CO3(-) and the mixture by 40 and 49% and increased the excretion of 14CO2 by 96%. Addition of CA to the perfusate had no effect. Thus, CO2 exchange is not significantly limited by pulmonary CA if inhibitors are absent. Tissue binding of [3H]acetazolamide injected into the pulmonary artery was diminished by 50% when acetazolamide concentrations reached 0.13 x 10(-6) M. Each liter of extravascular lung water contained 1.25 x 10(-6) mol of receptors for acetazolamide that were accessible to plasma during a single circulation. Binding of [3H]acetazolamide was also observed in lungs of anesthetized rabbits, suggesting that pulmonary CA is accessible to plasma in vivo as well as in situ.

Involvement of αENaC and Nedd4-2 in the conversion from lung fluid secretion to fluid absorption at birth in the rat as assayed by RNA interference analysis

2007 ◽  
Vol 293 (4) ◽  
pp. L1069-L1078 ◽  
Author(s):  
Tianbo Li ◽  
Shyny Koshy ◽  
Hans G. Folkesson
Keyword(s):  
Extravascular Lung Water ◽  
Fluid Secretion ◽  
Alveolar Epithelial Cells ◽  
Na Channel ◽  
Fluid Absorption ◽  
Lung Water ◽  
Fourfold Increase ◽  
Lung Fluid ◽  
Near Term

To explore interactions between the epithelial Na channel (ENaC) and neural precursor expressed, developmentally downregulated protein 4-2 (Nedd4-2) at the conversion of the rat lung from fluid secretion to absorption at birth, we used small-interfering RNA (siRNA) against αENaC and Nedd4-2. siRNA-generating plasmid DNA (pDNA) was administered via trans-thoracic intrapulmonary (ttip) injection 24 h before ENaC and Nedd4-2 expression, extravascular lung water, and mortality were measured. αENaC mRNA and protein were specifically reduced by ∼65% after pSi-4 injection. Nedd4-2 mRNA and protein were reduced by ∼60% after pSi-N1 injection. Interestingly, αENaC and βENaC mRNA and protein expression were increased after Nedd4-2 silencing. Extravascular lung water was significantly increased after αENaC silencing and reduced after Nedd4-2 silencing. αENaC silencing resulted in a fourfold increase in newborn mortality, whereas silencing Nedd4-2 did not affect mortality. We also isolated distal lung epithelial (DLE) cells after in vivo αENaC or Nedd4-2 silencing and measured αENaC or Nedd4-2 expression in freshly isolated DLE cells. In these DLE cells, there were attenuated αENaC or Nedd4-2 mRNA and protein, thus demonstrating that αENaC and Nedd4-2 silencing occurred in alveolar epithelial cells after ttip injection. We also looked for pDNA by PCR to determine pDNA presence in the lungs and found strong evidence for pDNA presence in both lungs. Thus we provide evidence that ENaC and Nedd4-2 are involved in the transition from lung fluid secretion to fluid absorption near term and at birth.

scholarly journals Detection of urease and carbonic anhydrase activity using a rapid and economical field test to assess microbially-induced carbonate precipitation

2020 ◽  
Author(s):  
Fernando Medina Ferrer ◽  
Kathryn Hobart ◽  
Jake V. Bailey
Keyword(s):  
Carbon Sequestration ◽  
Carbonic Anhydrase ◽  
Marker Gene ◽  
Cost Effective ◽  
Carbonic Anhydrase Activity ◽  
Soil Restoration ◽  
Reaction Products ◽  
Calcareous Fens ◽  
Molecular Approaches

ABSTRACTMicrobial precipitation of calcium carbonate has diverse engineering applications, from building and soil restoration, to carbon sequestration. Urease-mediated ureolysis and CO2 (de)hydration by carbonic anhydrase (CA) are known for their potential to precipitate carbonate minerals, yet many microbial community studies rely on marker gene or metagenomic approaches that are unable to determine in situ activity. Here, we developed fast and cost-effective tests for the field detection of urease and CA activity using pH-sensitive strips inside microcentrifuge tubes that change color in response to the reaction products of urease (NH3) and CA (CO2). Samples from a saline lake, a series of calcareous fens, and ferrous springs were assayed in the field, finding relatively high urease activity in lake samples, whereas CA activity was only detected in a ferrous spring. Incubations of lake microbes with urea resulted in significantly higher CaCO3 precipitation compared to incubations with a urease inhibitor. Therefore, the rapid assay indicated an on-site active metabolism potentially mediating carbonate mineralization. Field urease and CA activity assays complement molecular approaches and facilitate the search for carbonate-precipitating microbes and their in situ activity, which could be applied toward agriculture, engineering and carbon sequestration technologies.

Carbonic anhydrase in the midgut of larvalAedes aegypti: cloning, localization and inhibition

2002 ◽  
Vol 205 (5) ◽  
pp. 591-602 ◽  
Author(s):  
Maria del Pilar Corena ◽  
Theresa J. Seron ◽  
Herm K. Lehman ◽  
Judith D. Ochrietor ◽  
Andrea Kohn ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Aedes Aegypti ◽  
Fruit Fly ◽  
Cellular Heterogeneity ◽  
Carbonic Anhydrases ◽  
Larval Midgut ◽  
Posterior Midgut

SUMMARYThe larval mosquito midgut exhibits one of the highest pH values known in a biological system. While the pH inside the posterior midgut and gastric caeca ranges between 7.0 and 8.0, the pH inside the anterior midgut is close to 11.0. Alkalization is likely to involve bicarbonate/carbonate ions. These ions are produced in vivo by the enzymatic action of carbonic anhydrase. The purpose of this study was to investigate the role of this enzyme in the alkalization mechanism, to establish its presence and localization in the midgut of larval Aedes aegypti and to clone and characterize its cDNA. Here, we report the physiological demonstration of the involvement of carbonic anhydrase in midgut alkalization. Histochemistry and in situ hybridization showed that the enzyme appears to be localized throughout the midgut, although preferentially in the gastric caeca and posterior regions with specific cellular heterogeneity. Furthermore, we report the cloning and localization of the first carbonic anhydrase from mosquito larval midgut. A cDNA clone from Aedes aegypti larval midgut revealed sequence homology to α-carbonic anhydrases from vertebrates. Bioinformatics indicates the presence of at least six carbonic anhydrases or closely related genes in the genome of another dipteran, the fruit fly Drosophila melanogaster. Molecular analyses suggest that the larval mosquito may also possess multiple forms.

Indicator dilution using a fluorescent indicator

1982 ◽  
Vol 52 (5) ◽  
pp. 1368-1374 ◽  
Author(s):  
V. B. Elings ◽  
F. R. Lewis ◽  
J. Briggs
Keyword(s):  
Extravascular Lung Water ◽  
Detection System ◽  
Indicator Dilution ◽  
Fluorescent Light ◽  
Left Heart ◽  
Lung Water ◽  
Fluorescent Indicator ◽  
Double Indicator Dilution

In vitro and in vivo indicator-dilution measurements are made with a fluorescent indicator and a novel detection system using a catheter containing a single optical fiber that carries both the exciting and returning fluorescent light. These fluorescent-dilution measurements are compared with simultaneous green dye-dilution measurements. The double-indicator-dilution measurement of extravascular lung water using heat and fluorescence is compared with gravimetric measurements. Also investigated is the sensitivity of the fluorescent measurement to changes in O2 saturation and hematocrit of the blood. An example of the measurement of a right-to-left heart shunt with this new indicator is given.

scholarly journals The Carbonic Anhydrase Inhibitor Ethoxzolamide Inhibits the Mycobacterium tuberculosis PhoPR Regulon and Esx-1 Secretion and Attenuates Virulence

2015 ◽  
Vol 59 (8) ◽  
pp. 4436-4445 ◽  
Author(s):  
Benjamin K. Johnson ◽  
Christopher J. Colvin ◽  
David B. Needle ◽  
Felix Mba Medie ◽  
Patricia A. DiGiuseppe Champion ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Carbonic Anhydrase ◽  
Regulatory System ◽  
Carbonic Anhydrase Activity ◽  
Carbonic Anhydrase Inhibitor ◽  
Fluorescent Reporter ◽  
Content Type ◽  
Pathogen Virulence ◽  
Mutant Phenotypes

ABSTRACTMycobacterium tuberculosismust sense and adapt to host environmental cues to establish and maintain an infection. The two-component regulatory system PhoPR plays a central role in sensing and responding to acidic pH within the macrophage and is required forM. tuberculosisintracellular replication and growthin vivo. Therefore, the isolation of compounds that inhibit PhoPR-dependent adaptation may identify new antivirulence therapies to treat tuberculosis. Here, we report that the carbonic anhydrase inhibitor ethoxzolamide inhibits the PhoPR regulon and reduces pathogen virulence. We show that treatment ofM. tuberculosiswith ethoxzolamide recapitulatesphoPRmutant phenotypes, including downregulation of the core PhoPR regulon, altered accumulation of virulence-associated lipids, and inhibition of Esx-1 protein secretion. Quantitative single-cell imaging of a PhoPR-dependent fluorescent reporter strain demonstrates that ethoxzolamide inhibits PhoPR-regulated genes in infected macrophages and mouse lungs. Moreover, ethoxzolamide reducesM. tuberculosisgrowth in both macrophages and infected mice. Ethoxzolamide inhibitsM. tuberculosiscarbonic anhydrase activity, supporting a previously unrecognized link between carbonic anhydrase activity and PhoPR signaling. We propose that ethoxzolamide may be pursued as a new class of antivirulence therapy that functions by modulating expression of the PhoPR regulon and Esx-1-dependent virulence.

Extravascular lung water measurements and hemodynamic monitoring in the critically ill: bedside alternatives to the pulmonary artery catheter

2006 ◽  
Vol 291 (6) ◽  
pp. L1118-L1131 ◽  
Author(s):  
Warren Isakow ◽  
Daniel P. Schuster
Keyword(s):  
Cardiac Output ◽  
Pulmonary Artery ◽  
Pulmonary Artery Catheter ◽  
Critically Ill ◽  
Extravascular Lung Water ◽  
Ejection Time ◽  
Lung Water ◽  
Descending Aorta ◽  
Hemodynamic Management ◽  
Flow Through

The recently completed Fluid and Catheter Treatment Trial conducted by the National Institutes of Health ARDSNetwork casts doubt on the value of routine pulmonary artery catheterization for hemodynamic management of the critically ill. Several alternatives are available, and, in this review, we evaluate the theoretical, validation, and empirical databases for two of these: transpulmonary thermodilution measurements (yielding estimates of cardiac output, intrathoracic blood volume, and extravascular lung water) that do not require a pulmonary artery catheter, and hemodynamic measurements (including estimates of cardiac output and ejection time, a variable sensitive to intravascular volume) obtained by esophageal Doppler analysis of blood flow through the descending aorta. We conclude that both deserve serious consideration as a means of acquiring useful hemodynamic data for managing shock and fluid resuscitation in the critically ill, especially in those with acute lung injury and pulmonary edema, but that additional study, including carefully performed, prospective clinical trials demonstrating outcome benefit, is needed.

scholarly journals Effect of NaHS on carbonic anhydrase activity of human erythrocyte

2016 ◽  
Vol 7 (3) ◽  
pp. 23-27 ◽  
Author(s):  
Abhijit Bhakta ◽  
Maitreyi Bandyopadhyay ◽  
Sayantan Dasgupta ◽  
Santanu Sen ◽  
Arun Kumar ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Normal Saline ◽  
Carbonic Anhydrase Activity ◽  
Experimental Models ◽  
Test Tube ◽  
Dependent Manner ◽  
Carbonic Anhydrases ◽  
Medical Sciences ◽  
First Time

Background: In contrast to its role as poison, hydrogen sulfide (H2S) is recently considered as a gaso-transmitter which mediates important physiologic functions in humans. Evidence is accumulating to demonstrate that inhibitors of H2S production or therapeutic H2S donor compounds exert significant effects in various experimental models. Carbonic anhydrases (CA) are a group of zinc-containing metalloenzymes that catalyse the reversible hydration of carbon dioxide. CAs activity in erythrocytes (CAI and CAII) has recently been observed to be associated with various pathological conditions especially in diabetes mellitus, hypertension and lipid disorders. Alteration of this enzyme activity has been reported by the effect of advanced glycation end products methylglyoxal and reduced glutathione.   Aims and Objectives: As H2S, being a mediator of many physiological functions and synthesized in vivo, may affect functions of many intracellular proteins like carbonic anhydrase, the objective of this study is to find out if there is any change in the carbonic anhydrase activity under the effect of H2S- donor NaHS in dose dependant manner using RBC model in vitro.Materials and Methods: Blood sample was collected from forty (40) numbers of healthy volunteers of 18-40 years of in heparin containing vials and packed cells were prepared immediately by centrifugation  The packed erythrocytes were washed three times with normal saline and  diluted (1:10) with the normal saline. One ml each of diluted packed cells was taken in eight test tubes. Serial dilutions of NaHS (1to 250 µMol/L) was added to all the test tubes except for the first test tube where only normal saline was added and   incubated at room temperature for one hour. Haemolysates was prepared from the erythrocytes with equal volume of distilled water in each tube and the CA activity was determined in the haemolysates using standardized method.Results: There is significant increase of CA activity in dose dependent manner under the effect of NaHS and also compared to the activity of hemolysate prepared without NaHS.  Conclusions:Our study for the first time demonstrated that the Carbonic Anhydrase activity of erythrocytes is significantly increases by the effect of NaHS and this study reveals some important biological role of H2S and carbonic anhydrase.Asian Journal of Medical Sciences Vol. 7(3) 2016 23-27

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