CARBONIC ANHYDRASE AND CARBON FIXATION IN COCCOLITHOPHORIDS 1

Rates of carbon fixation in coccolithophorids in culture, unlike many other algae, are carbon limited at ambient levels of dissolved inorganic carbon (DIC). Apparently, plants often rely on activity of carbonic anhydrase (CA) to raise the level of CO2 in cells and achieve carbon saturation. However, CA activities in the coccolithophorids, Coccolithus (= Emiliania) huxleyi Lohmann and Hymenomonas (=Cricosphaera) carterae Braarud, were either not detectable or very low compared to activities in other systems, including other algae, higher plants, and representative animals. Furthermore, additions of CA to medium with 2 mM DIC at pH 8.1 resulted in nearly 30% enhancement of photosynthesis, but not coccolith formation. Although carbon fixation in coccolithophorids can be suppressed by the CA inhibitor acetazolamide, studies of CaCO3 nucleation revealed a non‐specific effect of the inhibitor. Using a 30 min assay based on pH decreases accompanying loss of dissolved. CO32‐, inhibition of crystal formation in the absence of CA at 1 mM acetazolamide was demonstrated for decalcified crab carapace, a tissue with which normal CaCo3 deposition in vitro has been shown. The results suggest only a minor role for CA in coccolithophorids.

[1]  I. Hall,et al.  Effects of imide analogs on enzymes required for cholesterol and fatty acid synthesis. , 1981, Journal of pharmaceutical sciences.

[2]  R. Roer Mechanisms of Resorption and Deposition of Calcium in the Carapace of the Crab Carcinus Maenas , 1980 .

[3]  C. Sikes,et al.  Photosynthesis and coccolith formation: Inorganic carbon sources and net inorganic reaction of deposition1 , 1980 .

[4]  A. Miller,et al.  Evidence for HCO(3) Transport by the Blue-Green Alga (Cyanobacterium) Coccochloris peniocystis. , 1980, Plant physiology.

[5]  H. Seliger,et al.  Inorganic carbon requirements of natural populations and laboratory cultures of some Chesapeake Bay phytoplankton , 1979 .

[6]  G. Findenegg Inorganic carbon transport in microalgae I: Location of carbonic anhydrase and HCO3−/OH− exchange , 1979 .

[7]  G. Price Sulfonamide inhibition of human alkaline phosphatase. , 1979, Clinica chimica acta; international journal of clinical chemistry.

[8]  E. Degens Why do organisms calcify , 1979 .

[9]  C. Sikes CALCIFICATION AND CATION SORPTION OF CLADOPHOHA GLOMERATA (CHLOROPHYTA) 1, 2 , 1978 .

[10]  T. Cao,et al.  Inhibitory effect of acetazolamide on the activity of acetyl CoA carboxylase of mouse liver. , 1978, Life sciences.

[11]  J Gutknecht,et al.  Diffusion of carbon dioxide through lipid bilayer membranes. Effects of carbonic anhydrase, bicarbonate, and unstirred layers , 1977, The Journal of general physiology.

[12]  M. M. Bradford A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[13]  J. Talling,et al.  The depletion of carbon dioxide from lake water by phytoplankton , 1976 .

[14]  J. Ferguson,et al.  Kinetics of carbon dioxide uptake by phytoplankton at high pH1 , 1975 .

[15]  E. Nelson,et al.  Carbonic anhydrase levels in chlamydomonas , 1969 .

[16]  L. Lavine,et al.  Interference with Deposition of Minerals in a Coccolithophorid Protozoon , 1969 .

[17]  C. Slack,et al.  Distribution of carbonic anhydrase in relation to the C4 pathway of photosynthesis , 1968 .

[18]  T. Maren,et al.  Carbonic anhydrase: chemistry, physiology, and inhibition. , 1967, Physiological reviews.

[19]  R. Tashian,et al.  Characterization of a mutant human erythrocyte carbonic anhydrase: carbonic anhydrase Ic-Guam. The amino acid substitution and carboxylesterase and hydratase activities. , 1966, Archives of biochemistry and biophysics.

[20]  R. M. Pytkowicz Rates of Inorganic Calcium Carbonate Nucleation , 1965, The Journal of Geology.

[21]  Robert P. Davis The Kinetics of the Reaction of Human Erythrocyte Carbonic Anhydrase. I. Basic Mechanism and the Effect of Electrolytes on Enzyme Activity , 1958 .

[22]  C. Sikes,et al.  Functions of coccolith formation1 , 1982 .

[23]  A. Pentecost Calcification in Plants , 1980 .

[24]  T. Cao,et al.  Action of acetazolamide on liver pyruvate carboxylase activity, glycogenolysis and gluconeogenesis of mice. , 1978, The International journal of biochemistry.

[25]  G. A. Kerkut Microfiche—a communication revolution , 1977 .

[26]  D. Graham,et al.  Carbonate Dehydratase in Marine Organisms of the Great Barrier Reef , 1976 .

[27]  E. Nielsen The Uptake of Free CO2 and HCO3‐ during Photosynthesis of Plankton Algae with Special Reference to the Coccolithophorid Coccolithus huxleyi , 1966 .

[28]  H. Waris Cytophysiological studies on Micrasterias I. Nuclear and cell division. , 1950 .