Membrane permeability to CO2 of four species of diatoms and of artificial lipid membranes

Range 0.015 cm/sec - 0.056 cm/sec artificial lipid membranes ~0.1 cm/sec
Organism Diatoms
Reference Hopkinson BM, Dupont CL, Allen AE, Morel FM. Efficiency of the CO2-concentrating mechanism of diatoms. Proc Natl Acad Sci U S A. 2011 Mar 8 108(10):3830-7. doi: 10.1073/pnas.1018062108 p.2 right column 2nd paragraphPubMed ID21321195
Primary Source [9] Gutknecht J, Bisson MA, Tosteson FC. Diffusion of carbon dioxide through lipid bilayer membranes: effects of carbonic anhydrase, bicarbonate, and unstirred layers. J Gen Physiol. 1977 Jun69(6):779-94PubMed ID408462
Method P.1 right column 3rd paragraph: "The bulk of [investigators’] experiments consist of time courses of 18O depletion from labeled inorganic carbon, a process catalyzed by the presence of the enzyme carbonic anhydrase (CA) in cells. CA, which catalyzes the hydration of CO2 and dehydration of HCO3−, plays critical roles in CCMs [CO(2) concentrating mechanisms] and is present in all [their] experimental organisms: Thalassiosira weissflogii, T. pseudonana, T. oceanica, and Phaedactylum tricornutum, (SI Text, Experimental Organisms)."
Comments P.2 right column 2nd paragraph: "According to [investigators’] experimental data, the cytoplasmic membrane of diatoms is highly permeable to CO2. Calculated values of Pc [membrane permeability to CO2] range between 1.5 × 10^−2 and 5.6 × 10^−2 cm/s for the four species that [they] studied, indicating permeabilities that are just below those of artificial lipid membranes (∼10^−1 cm/s) (primary source)."
Entered by Uri M
ID 116872