Effect of dissolved inorganic carbon on the expression of carboxysomes, localization of Rubisco and the mode of inorganic carbon transport in cells of the cyanobacterium Synechococcus UTEX 625

1993 ◽  
Vol 159 (1) ◽  
pp. 21-29 ◽  
Author(s):  
R. Michael L. McKay ◽  
Sarah P. Gibbs ◽  
George S. Espie
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Inorganic Carbon Transport ◽  
Carbon Transport ◽  
In Cells

Regulation of dissolved inorganic carbon transport in green algae

1998 ◽  
Vol 76 (6) ◽  
pp. 1072-1083 ◽  
Author(s):  
Yusuke Matsuda ◽  
Gale G. Bozzo ◽  
Brian Colman
Keyword(s):  
Green Algae ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Inorganic Carbon Transport ◽  
Carbon Transport

Sources and mechanisms of inorganic carbon transport for coral calcification and photosynthesis

2000 ◽  
Vol 203 (22) ◽  
pp. 3445-3457 ◽  
Author(s):  
P. Furla ◽  
I. Galgani ◽  
I. Durand ◽  
D. Allemand
Keyword(s):  
Inorganic Carbon ◽  
Sea Water ◽  
External Medium ◽  
Dissolved Inorganic Carbon ◽  
Double Labelling ◽  
Stylophora Pistillata ◽  
Coral Calcification ◽  
Lighting Conditions ◽  
Inorganic Carbon Transport ◽  
Carbon Transport

The sources and mechanisms of inorganic carbon transport for scleractinian coral calcification and photosynthesis were studied using a double labelling technique with H(14)CO(3) and (45)Ca. Clones of Stylophora pistillata that had developed into microcolonies were examined. Compartmental and pharmacological analyses of the distribution of(45)Ca and H(14)CO(3) in the coelenteron, tissues and skeleton were performed in dark or light conditions or in the presence of various seawater HCO(3)(−) concentrations. For calcification, irrespective of the lighting conditions, the major source of dissolved inorganic carbon (DIC) is metabolic CO(2) (70–75% of total CaCO(3) deposition), while only 25–30% originates from the external medium (seawater carbon pool). These results are in agreement with the observation that metabolic CO(2) production in the light is at least six times greater than is required for calcification. This source is dependent on carbonic anhydrase activity because it is sensitive to ethoxyzolamide. Seawater DIC is transferred from the external medium to the coral skeleton by two different pathways: from sea water to the coelenteron, the passive paracellular pathway is largely sufficient, while a DIDS-sensitive transcellular pathway appears to mediate the flux across calicoblastic cells. Irrespective of the source, an anion exchanger performs the secretion of DIC at the site of calcification. Furthermore, a fourfold light-enhanced calcification of Stylophora pistillata microcolonies was measured. This stimulation was only effective after a lag of 10 min. These results are discussed in the context of light-enhanced calcification. Characterisation of the DIC supply for symbiotic dinoflagellate photosynthesis demonstrated the presence of a DIC pool within the tissues. The size of this pool was dependent on the lighting conditions, since it increased 39-fold after 3 h of illumination. Passive DIC equilibration through oral tissues between sea water and the coelenteric cavity is insufficient to supply this DIC pool, suggesting that there is an active transepithelial absorption of inorganic carbon sensitive to DIDS, ethoxyzolamide and iodide. These results confirm the presence of CO(2)-concentrating mechanisms in coral cells. The tissue pool is not, however, used as a source for calcification since no significant lag phase in the incorporation of external seawater DIC was measured.

Active HCO3− transport in cyanobacteria

1991 ◽  
Vol 69 (5) ◽  
pp. 936-944 ◽  
Author(s):  
George S. Espie ◽  
Anthony G. Miller ◽  
Ramani A. Kandasamy ◽  
David T. Canvin
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Reaction Medium ◽  
Transport Systems ◽  
Bicarbonate Transport ◽  
Key Words Cyanobacteria ◽  
Sodium Dependent ◽  
Rate Of Photosynthesis ◽  
Low Levels ◽  
In Cells

Cyanobacteria possess systems for the active transport of both CO2 and HCO3−. While the active CO2 transport system seems to be present in cells grown on all levels of CO2 or dissolved inorganic carbon, the bicarbonate transport systems are only present in cells grown on low levels of CO2 or dissolved inorganic carbon (air levels or lower). Active bicarbonate transport can be shown to occur when the rate of photosynthesis exceeds that which could be sustained by the production of CO2 from the dehydration of bicarbonate or when CO2 transport is inhibited with carbon oxysulfide or hydrogen sulfide. Two systems for active bicarbonate transport have been identified: one is dependent on the presence of millimolar concentrations of sodium, and the other is independent of the sodium requirement. Cells grown with air bubbling normally possess the first whereas cells grown in standing culture normally possess the second. The sodium-dependent bicarbonate transport can be inhibited by omitting sodium from the reaction medium or competitively with lithium when sodium is present. Monensin and amiloride also inhibit sodium-dependent bicarbonate transport. It does not appear to be inhibited by ethoxyzolamide. The inhibition of sodium-independent bicarbonate transport is not yet established. Bicarbonate transport appears to have no effect on CO2 transport and CO2 transport appears to have no effect on bicarbonate transport. Hence, the transport systems seems to be independent. Although a number of mechanisms have been proposed for bicarbonate transport, the experimental data are not sufficient to clearly distinguish between them. Key words: cyanobacteria, active CO2 transport, active HCO3− transport, photosynthesis, sodium.

Sign in / Sign up

Export Citation Format

Share Document