Carbonic anhydrase activity and inorganic carbon fluxes in low- and high-C1 cells of Chlamydomonas reinhardtu and Scenedesmus obliquus

1994 ◽  
Vol 90 (3) ◽  
pp. 537-547 ◽  
Author(s):  
Kristin Palmqvist ◽  
Jian-Wei Yu ◽  
Murray R. Badger
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Scenedesmus Obliquus ◽  
Carbon Fluxes ◽  
Carbonic Anhydrase Activity

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.

Studies on the carbonic anhydrase activity in Synechocystis PCC6803 wild type and an acetazolamide-resistant mutant

1991 ◽  
Vol 69 (5) ◽  
pp. 1103-1108 ◽  
Author(s):  
S. Bedu ◽  
F. Joset
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Physiological Role ◽  
Resistant Mutant ◽  
Carbonic Anhydrase Activity ◽  
Wild Type ◽  
Synechocystis Pcc6803 ◽  
Physiological Analysis ◽  
Carbon Concentrations

The problem of the role and the localization of carbonic anhydrase activity in cyanobacteria has been addressed by two approaches using strain Synechocystis PCC6803. Physiological analysis of the differential effects of carbonic anhydrase inhibitors on the entry and accumulation of CO2 in cells grown under low or high inorganic carbon concentrations and determination of carbonic anhydrase activities in cellular subfractions led to the hypothesis of the presence of two different enzymes in this strain. This conclusion is compatible with current models. Only the internal enzyme could be regulated by variations of the external inorganic carbon concentrations. A parallel analysis of a mutant of this strain resistant to the inhibitor acetazolamide supported the hypothesis of the presence of two enzymes. This clone would be selectively impaired in the carbonic anhydrase activity involved in the maintenance of the internal CO2 pool, while its transport capacity is unchanged. Key words: carbonic anhydrase, physiological role, localization, inhibitors, cyanobacteria, mutant.

Inorganic carbon transport in some marine microalgal species

1991 ◽  
Vol 69 (5) ◽  
pp. 1032-1039 ◽  
Author(s):  
M. J. Merrett
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Silicone Oil ◽  
Ph Regulation ◽  
Carbonic Anhydrase Activity ◽  
Carbon Accumulation ◽  
Bicarbonate Transport ◽  
High Affinity ◽  
Inorganic Carbon Transport ◽  
Carbon Transport

Inorganic carbon transport was investigated in a range of marine microalgae. A small-celled strain of Stichococcus bacillaris, containing appreciable carbonic anhydrase activity, showed a high affinity for CO2, while measurement of the internal inorganic carbon pool by the silicone oil layer centrifugal filtering technique showed cells concentrated inorganic carbon up to 20-fold in relation to the external medium at pH 5.0 but not pH 8.3. The addition of 14CO2 or H14CO3− to cells in short-term kinetic experiments at pH 8.3 confirmed that only CO2 provides the exogenous substrate for substantial inorganic carbon accumulation within the cell. High-affinity HCO3− transport in Phaeodactylum tricornutum and Porphyridium purpureum is dependent on sodium ions, while intracellular carbonic anhydrase increased the steady-state flux of CO2 from inside the plasmalemma to Rubisco. In the presence of HCO3− the intracellular pH in cells of P. purpureum is 7.1 but on carbon starvation the pH falls to 6.0. Ethoxyzolamide blocks bicarbonate-dependent alkalinization of the cytosol, confirming a central role for carbonic anhydrase–bicarbonate in cytosolic pH regulation. Carbonic anhydrase activity is pH dependent in P. purpureum so synergistic interaction between CO2 uptake and bicarbonate transport may occur.

Characterisation of inorganic carbon fluxes, carbonic anhydrase(s) and ribulose-1,5-biphosphate carboxylase-oxygenase in the green unicellular alga Coccomyxa

Planta ◽  
1995 ◽  
Vol 197 (2) ◽  
Author(s):  
Kristin Palmqvist ◽  
Dieter S�ltemeyer ◽  
Pierre Baldet ◽  
T.John Andrews ◽  
MurrayR. Badger
Keyword(s):  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Carbon Fluxes ◽  
Unicellular Alga

Changes in inorganic carbon uptake during the progression of a dinoflagellate bloom in a lake ecosystem

1998 ◽  
Vol 76 (6) ◽  
pp. 1043-1051 ◽  
Author(s):  
Ilana Berman-Frank ◽  
Jonathan Erez ◽  
Aaron Kaplan
Keyword(s):  
Carbonic Anhydrase ◽  
Growth Rates ◽  
Inorganic Carbon ◽  
Carbonic Anhydrase Activity ◽  
Quantum Yields ◽  
Carbon Uptake ◽  
In Situ Growth ◽  
Photosynthetic Rates ◽  
Inorganic Carbon Uptake

The physiological, biochemical, and genetic aspects of inorganic (Ci) carbon uptake in aquatic plants and algae have been studied extensively. Yet, to date, few studies examined these questions on dominant phytoplankton populations in their natural environment. Lake Kinneret, Israel, provides a good example of a system in which changes in CO2 availability play a vital role in the ecophysiology of inorganic carbon uptake and in the population dynamics during the annual bloom of the dinoflagellate Peridinium gatunense Nygaard. In this study we investigated whether the availability of CO2(aq) limited growth rates and primary productivity of in situ populations of P. gatunense and focused on the role of adaptive mechanisms for Ci uptake. At the onset of the bloom, when epilimnetic pH was low ( = 8) and Ci concentrations were high ( = 2.5 mM), carbonic anhydrase activity and cellular affinity to CO2(aq) were comparatively low. At this time photosynthetic rates, quantum yields, and in situ growth rates were high. As P. gatunense biomass increased, inorganic carbon decreased by 40%, while CO2(aq) concentrations declined 50-fold to values less than 2 µM. The algae adapted by acquiring a CO2-concentrating mechanism indicated by (i) intracellular Ci-concentrations higher by a factor of 5-70 relative to the ambient Ci; (ii) levels of carbonic anhydrase activity higher by 5- to 50-fold than those at the beginning of the bloom; and (iii) enhanced affinity for Ci and CO2(aq) 3- and 40-fold higher, respectively, than affinities at the start of the bloom. These mechanistic changes in carbon uptake were reflected in declining photosynthetic rates and quantum yields as well as in the carbon isotopic composition with lower fractionation (13C enrichment) of the algae as the bloom progressed. Finally, despite induction of adaptive uptake mechanisms to low CO2 availability; scarcity of other nutrients combined with low CO2 concentrations, increased temperatures, and increased turbulence cause a decline in in situ growth rates and the collapse of the dinoflagellate biomass.Key words: dinoflagellates, inorganic carbon uptake, CCM, carbonic anhydrase, Peridinium gatunense.

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