The role of extracellular carbonic anhydrase activity in inorganic carbon utilization of Phaeocystis globosa (Prymnesiophyceae): A comparison with other marine algae using the isotopic disequilibrium technique

2000 ◽  
Vol 45 (2) ◽  
pp. 372-380 ◽  
Author(s):  
J. Theo M. Elzenga ◽  
Hidde B. A. Prins ◽  
Jacqueline Stefels
Keyword(s):  
Carbonic Anhydrase ◽  
Marine Algae ◽  
Inorganic Carbon ◽  
Carbonic Anhydrase Activity ◽  
Carbon Utilization ◽  
Phaeocystis Globosa ◽  
Inorganic Carbon Utilization ◽  
Isotopic Disequilibrium

Extracellular carbonic anhydrase of Chlamydomonas reinhardtii: localization, structural properties, and catalytic properties

1991 ◽  
Vol 69 (5) ◽  
pp. 1079-1087 ◽  
Author(s):  
H. David Husic
Keyword(s):  
Plasma Membrane ◽  
Carbonic Anhydrase ◽  
Chlamydomonas Reinhardtii ◽  
Inorganic Carbon ◽  
Catalytic Properties ◽  
Physiological Role ◽  
Carbon Utilization ◽  
Unicellular Green Alga ◽  
Inorganic Carbon Utilization ◽  
Inorganic Carbon Acquisition

In the unicellular green alga Chlamydomonas reinhardtii, a form of the enzyme carbonic anhydrase that is localized outside of the plasma membrane is an inducible component of a system that is involved in inorganic carbon acquisition and concentration from the growth medium. This article contains a review and analysis of the current literature regarding the extracellular carbonic anhydrase from Chlamydomonas reinhardtii and presents some new studies on its extracellular localization, physiological role in inorganic carbon acquisition, and some of the structural and catalytic properties of the enzyme. Key words: carbonic anhydrase, Chlamydomonas reinhardtii, inorganic carbon utilization.

Adaptation of Elodea and Potamogeton to Different Inorganic Carbon Levels and the Mechanism for Photosynthetic Bicarbonate Utilisation

1988 ◽  
Vol 15 (6) ◽  
pp. 727 ◽  
Author(s):  
JTM Elzenga ◽  
HBA Prins
Keyword(s):  
Carbonic Anhydrase ◽  
Aquatic Macrophytes ◽  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Carbonic Anhydrase Activity ◽  
Small Contribution ◽  
Low Co2 ◽  
Unicellular Algae ◽  
Submerged Aquatic Macrophytes ◽  
Isotopic Disequilibrium

The different abilities of three submerged aquatic macrophytes, Elodea canadensis, E. nutallii and Potamogeton lucens, cultured under high and low CO2 concentrations, to utilise bicarbonate was found to correlate with the ability to exhibit a polar leaf pH reaction (i. e. acidification of the medium on one side of the leaf). The utilisation of bicarbonate did not depend on the induction of extracellular carbonic anhydrase activity as found with unicellular algae. Although the bicarbonate utilisation was inhibited by acetazolamide, an inhibitor of carbonic anhydrase activity, there was no difference in the concentration of extracellular carbonic anhydrase between leaves with high and with low bicarbonate utilisation. In experiments using the isotopic disequilibrium method we found only a small contribution of bicarbonate to the carbon fixation of protoplast. The percentage of bicarbonate contribution to the fixation did not differ between protoplasts isolated from Potamogeton leaves with high bicarbonate utilisation (from a low CO2 culture) and from leaves with low bicarbonate utilisation (from a high CO2 culture). We conclude that bicarbonate utilisation depends on the polar leaf pH reaction and that CO2 is the carbon species that is taken up by the leaf.

scholarly journals The Periplasmic α-Carbonic Anhydrase Activity of Helicobacter pylori Is Essential for Acid Acclimation

2005 ◽  
Vol 187 (2) ◽  
pp. 729-738 ◽  
Author(s):  
Elizabeth A. Marcus ◽  
Amiel P. Moshfegh ◽  
George Sachs ◽  
David R. Scott
Keyword(s):  
Helicobacter Pylori ◽  
Membrane Potential ◽  
Carbonic Anhydrase ◽  
Membrane Integrity ◽  
Carbonic Anhydrase Activity ◽  
Knockout Mutant ◽  
Inner Membrane ◽  
Acid Acclimation

ABSTRACT The role of the periplasmic α-carbonic anhydrase (α-CA) (HP1186) in acid acclimation of Helicobacter pylori was investigated. Urease and urea influx through UreI have been shown to be essential for gastric colonization and for acid survival in vitro. Intrabacterial urease generation of NH3 has a major role in regulation of periplasmic pH and inner membrane potential under acidic conditions, allowing adequate bioenergetics for survival and growth. Since α-CA catalyzes the conversion of CO2 to HCO3 −, the role of CO2 in periplasmic buffering was studied using an α-CA deletion mutant and the CA inhibitor acetazolamide. Western analysis confirmed that α-CA was bound to the inner membrane. Immunoblots and PCR confirmed the absence of the enzyme and the gene in the α-CA knockout. In the mutant or in the presence of acetazolamide, there was an ∼3 log10 decrease in acid survival. In acid, absence of α-CA activity decreased membrane integrity, as observed using membrane-permeant and -impermeant fluorescent DNA dyes. The increase in membrane potential and cytoplasmic buffering following urea addition to wild-type organisms in acid was absent in the α-CA knockout mutant and in the presence of acetazolamide, although UreI and urease remained fully functional. At low pH, the elevation of cytoplasmic and periplasmic pH with urea was abolished in the absence of α-CA activity. Hence, buffering of the periplasm to a pH consistent with viability depends not only on NH3 efflux from the cytoplasm but also on the conversion of CO2, produced by urease, to HCO3 − by the periplasmic α-CA.

Role of intracellular carbonic anhydrase in inorganic-carbon assimilation by Porphyridium purpureum

Planta ◽  
1987 ◽  
Vol 172 (4) ◽  
pp. 508-513 ◽  
Author(s):  
G. K. Dixon ◽  
B. N. Patel ◽  
M. J. Merrett
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Carbon Assimilation ◽  
Porphyridium Purpureum

Fractionation of carbonic anhydrase activity in Gracilaria sp. (Rhodophyta) and Enteromorpha intestinalis (Chlorophyta): changes in the extracellular activity in response to inorganic carbon levels

2000 ◽  
Vol 27 (12) ◽  
pp. 1161 ◽  
Author(s):  
Jesús R. Andría ◽  
Juan J. Vergara ◽  
J. Lucas Pérez-Lloréns
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Soluble Fraction ◽  
Total Activity ◽  
Carbonic Anhydrase Activity ◽  
Enteromorpha Intestinalis ◽  
Short Term ◽  
Carbon Availability ◽  
Species Specific ◽  
Extracellular Activity

The presence of different carbonic anhydrase (EC 4.2.1.1) activities has been investigated in the intertidal macroalgae Gracilaria sp. and Enteromorpha intestinalis (L.) Nees by using fractionation techniques. Activities, measured potentiometrically, were recorded for all fractions in both species, including those containing proteins associated with chloroplast membranes. In Gracilaria sp., most of the total activity was present in the soluble fraction, while similar activities were obtained for all fractions in E. intestinalis. By using inhibitors with a different capacity to enter the cell (acetazolamide and 6-ethoxyzolamide, inhibitors of external and total activity, respectively), a surface-accessible location was indicated for a high proportion of the soluble activity obtained in Gracilaria sp. In E. intestinalis, the inhibitor assays showed a substantial dependence of photosynthesis on intracellular activity. The short-term regulation of the extracellular activity in response to inorganic carbon availability was also examined in both macroalgae. Rapid repression (after 2 h) of the activity was recorded when Gracilaria sp. was transferred from limited to replete carbon conditions, while a fairly constant activity was recorded for E. intestinalis. In contrast, an increase of external activity was obtained for both macroalgae after being transferred to carbon-limited conditions, this response being more pronounced in E. intestinalis. Our results suggest the occurrence of a species-specific carbonic anhydrase system.

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