Mg Isotope Fractionation during Uptake by a Rock-Inhabiting, Model Microcolonial Fungus Knufia petricola at Acidic and Neutral pH

The model rock-inhabiting microcolonial fungus Knufia petricola fractionates stable Mg isotopes in a time- and pH-dependent manner. During growth, the increase of 26Mg/24Mg in the fungal cells relative to the growth media amounted to 0.65 ± 0.14‰ at pH 6 and 1.11 ± 0.35‰ at pH 3. We suggest a consta...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 2017-09, Vol.51 (17), p.9691-9699
Main Authors: Pokharel, Rasesh, Gerrits, Ruben, Schuessler, Jan A., Floor, Geerke H., Gorbushina, Anna A., von Blanckenburg, Friedhelm
Format: Article
Language:English
Subjects:
Acidity
Ascomycota
Cell walls
Cells
Chemical Fractionation
Cytoplasmic membranes
Fluxes
Fractionation
Fungi
Growth media
Hydrogen ions
Hydrogen-Ion Concentration
Isotope fractionation
Isotopes
Magnesium
Magnesium - chemistry
Membranes
Metabolic pathways
pH effects
Ribosomes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The model rock-inhabiting microcolonial fungus Knufia petricola fractionates stable Mg isotopes in a time- and pH-dependent manner. During growth, the increase of 26Mg/24Mg in the fungal cells relative to the growth media amounted to 0.65 ± 0.14‰ at pH 6 and 1.11 ± 0.35‰ at pH 3. We suggest a constant equilibrium fractionation factor during incorporation of Mg into ribosomes and ATP as a cause of enrichment of 26Mg in the cells. We suggest too that the proton gradient across the cell wall and cytoplasmic membrane controls Mg2+ transport into the fungal cell. As the strength of this gradient is a function of extracellular solution pH, the pH-dependence on Mg isotope fractionation is thus due to differences in fungal cell mass fluxes. Through a mass balance model we show that Mg uptake into the fungal cell is not associated with a unique Mg isotope fractionation factor. This Mg isotope fractionation dependence on pH might also be observed in any organism with cells that follow similar Mg uptake and metabolic pathways and serves to reveal Mg cycling in ecosystems.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.7b01798