Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis
Symbiotic cnidarians absorb inorganic carbon from seawater to supply intracellular dinoflagellates with CO2 for their photosynthesis. To determine the mechanism of inorganic carbon transport by animal cells, we used plasma membrane vesicles prepared from ectodermal cells isolated from tentacles of t...
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ftunivmilanoair:oai:air.unimi.it:2434/39736 2024-02-11T10:02:52+01:00 Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis P. Furla D. Allemand M.N. Orsenigo P. Furla D. Allemand M.N. Orsenigo 2000 http://hdl.handle.net/2434/39736 eng eng American physiological society info:eu-repo/semantics/altIdentifier/pmid/10749774 volume:278 issue:4 firstpage:R870 lastpage:R881 journal:AMERICAN JOURNAL OF PHYSIOLOGY. REGULATORY, INTEGRATIVE AND COMPARATIVE PHYSIOLOGY http://hdl.handle.net/2434/39736 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-0033995429 Anthozoan Carbon-concentrating mechanism HCO3/- transport Sea anemone Symbiosis Settore BIO/09 - Fisiologia info:eu-repo/semantics/article 2000 ftunivmilanoair 2024-01-23T23:17:01Z Symbiotic cnidarians absorb inorganic carbon from seawater to supply intracellular dinoflagellates with CO2 for their photosynthesis. To determine the mechanism of inorganic carbon transport by animal cells, we used plasma membrane vesicles prepared from ectodermal cells isolated from tentacles of the sea anemone, Anemonia viridis. H14CO3/- uptake in the presence of an outward NaCl gradient or inward H+ gradient, showed no evidence for a Cl- or H+- driven HCO3/- transport. H14CO3/- and 36Cl- uptakes were stimulated by a positive inside-membrane diffusion potential, suggesting the presence of HCO3/- and Cl- conductances. A carbonic anhydrase (CA) activity was measured on plasma membrane (4%) and in the cytoplasm of the ectodermal cells (96%) and was sensitive to acetazolamide (IC50 = 20 nM) and ethoxyzolamide (IC50 = 2.5 nM). A strong DIDS-sensitive H+ATPase activity was observed (IC50 = 14 μM). This activity was also highly sensitive to vanadate and allyl isothiocyanate, two inhibitors of P-type H+-ATPases. Present data suggest that HCO3/- absorption by ectodermal cells is carried out by H+ secretion by H+-ATPase, resulting in the formation of carbonic acid in the surrounding seawater, which is quickly dehydrated into CO2 by a membrane-bound CA. CO2 then diffuses passively into the cell where it is hydrated in HCO3/- by a cytosolic CA. Article in Journal/Newspaper Carbonic acid The University of Milan: Archivio Istituzionale della Ricerca (AIR) |
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Open Polar |
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The University of Milan: Archivio Istituzionale della Ricerca (AIR) |
op_collection_id |
ftunivmilanoair |
language |
English |
topic |
Anthozoan Carbon-concentrating mechanism HCO3/- transport Sea anemone Symbiosis Settore BIO/09 - Fisiologia |
spellingShingle |
Anthozoan Carbon-concentrating mechanism HCO3/- transport Sea anemone Symbiosis Settore BIO/09 - Fisiologia P. Furla D. Allemand M.N. Orsenigo Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
topic_facet |
Anthozoan Carbon-concentrating mechanism HCO3/- transport Sea anemone Symbiosis Settore BIO/09 - Fisiologia |
description |
Symbiotic cnidarians absorb inorganic carbon from seawater to supply intracellular dinoflagellates with CO2 for their photosynthesis. To determine the mechanism of inorganic carbon transport by animal cells, we used plasma membrane vesicles prepared from ectodermal cells isolated from tentacles of the sea anemone, Anemonia viridis. H14CO3/- uptake in the presence of an outward NaCl gradient or inward H+ gradient, showed no evidence for a Cl- or H+- driven HCO3/- transport. H14CO3/- and 36Cl- uptakes were stimulated by a positive inside-membrane diffusion potential, suggesting the presence of HCO3/- and Cl- conductances. A carbonic anhydrase (CA) activity was measured on plasma membrane (4%) and in the cytoplasm of the ectodermal cells (96%) and was sensitive to acetazolamide (IC50 = 20 nM) and ethoxyzolamide (IC50 = 2.5 nM). A strong DIDS-sensitive H+ATPase activity was observed (IC50 = 14 μM). This activity was also highly sensitive to vanadate and allyl isothiocyanate, two inhibitors of P-type H+-ATPases. Present data suggest that HCO3/- absorption by ectodermal cells is carried out by H+ secretion by H+-ATPase, resulting in the formation of carbonic acid in the surrounding seawater, which is quickly dehydrated into CO2 by a membrane-bound CA. CO2 then diffuses passively into the cell where it is hydrated in HCO3/- by a cytosolic CA. |
author2 |
P. Furla D. Allemand M.N. Orsenigo |
format |
Article in Journal/Newspaper |
author |
P. Furla D. Allemand M.N. Orsenigo |
author_facet |
P. Furla D. Allemand M.N. Orsenigo |
author_sort |
P. Furla |
title |
Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
title_short |
Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
title_full |
Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
title_fullStr |
Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
title_full_unstemmed |
Involvement of H+-ATPase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
title_sort |
involvement of h+-atpase and carbonic anhydrase in inorganic carbon uptake for endosymbiont photosynthesis |
publisher |
American physiological society |
publishDate |
2000 |
url |
http://hdl.handle.net/2434/39736 |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_relation |
info:eu-repo/semantics/altIdentifier/pmid/10749774 volume:278 issue:4 firstpage:R870 lastpage:R881 journal:AMERICAN JOURNAL OF PHYSIOLOGY. REGULATORY, INTEGRATIVE AND COMPARATIVE PHYSIOLOGY http://hdl.handle.net/2434/39736 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-0033995429 |
_version_ |
1790598957001342976 |