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Ammonium and methylamine transport by the ectomycorrhizal fungus Paxillus involutus and ectomycorrhizas

Javelle, Arnaud; Chalot, Michel; Söderström, Bengt LU and Botton, Bernard (1999) In FEMS Microbiology Ecology 30(4). p.355-366
Abstract
Using [C-14]methylamine as an analogue of ammonium, the kinetics and the energetics of NH: transport were studied in the ectomycorrhizal fungus, Paxillus involutus (Batsch) Fr. The apparent half-saturation constant (K-m) and the maximum uptake rate (V-max) for the carrier-mediated transport derived from the Eadie-Hofstee transformation were 180 mu M and 380 nmol (mg dry wt)(-1) min(-1,) respectively. Both pH dependence and inhibition by protonophores indicate that methylamine transport in P. involutus was dependent on the electrochemical H+ gradient. Both long-term and short-term uptake experiments were consistent with regulation of ammonium/methylamine transport processes by the presence of an organic nitrogen source. Analysis of... (More)
Using [C-14]methylamine as an analogue of ammonium, the kinetics and the energetics of NH: transport were studied in the ectomycorrhizal fungus, Paxillus involutus (Batsch) Fr. The apparent half-saturation constant (K-m) and the maximum uptake rate (V-max) for the carrier-mediated transport derived from the Eadie-Hofstee transformation were 180 mu M and 380 nmol (mg dry wt)(-1) min(-1,) respectively. Both pH dependence and inhibition by protonophores indicate that methylamine transport in P. involutus was dependent on the electrochemical H+ gradient. Both long-term and short-term uptake experiments were consistent with regulation of ammonium/methylamine transport processes by the presence of an organic nitrogen source. Analysis of methylamine uptake by different P. involutus isolates revealed no obvious trend in the uptake capacities in relation to N deposition at the collection site. Kinetic parameters were determined in P. involutus/Betula pendula (Roth.) axenic association and in detached mycorrhizal roots isolated from forest sites. Enhanced methylamine uptake in the presence of the fungal symbiont was demonstrated. Homogeneous V-max values were found for axenic and detached mycorrhizas, whereas K-m values showed greater variations. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved. (Less)
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Contribution to journal
publication status
published
subject
keywords
Ammonium/methylamine uptake, Kinetic experiment, Mycorrhiza, Paxillus involutus
in
FEMS Microbiology Ecology
volume
30
issue
4
pages
355 - 366
publisher
Elsevier
external identifiers
  • scopus:0032754798
ISSN
1574-6941
DOI
10.1111/j.1574-6941.1999.tb00663.x
language
English
LU publication?
yes
id
e7362385-cadd-4a2b-8679-6e84047a827c (old id 2226217)
date added to LUP
2012-01-16 13:34:22
date last changed
2017-10-01 03:53:59
@article{e7362385-cadd-4a2b-8679-6e84047a827c,
  abstract     = {Using [C-14]methylamine as an analogue of ammonium, the kinetics and the energetics of NH: transport were studied in the ectomycorrhizal fungus, Paxillus involutus (Batsch) Fr. The apparent half-saturation constant (K-m) and the maximum uptake rate (V-max) for the carrier-mediated transport derived from the Eadie-Hofstee transformation were 180 mu M and 380 nmol (mg dry wt)(-1) min(-1,) respectively. Both pH dependence and inhibition by protonophores indicate that methylamine transport in P. involutus was dependent on the electrochemical H+ gradient. Both long-term and short-term uptake experiments were consistent with regulation of ammonium/methylamine transport processes by the presence of an organic nitrogen source. Analysis of methylamine uptake by different P. involutus isolates revealed no obvious trend in the uptake capacities in relation to N deposition at the collection site. Kinetic parameters were determined in P. involutus/Betula pendula (Roth.) axenic association and in detached mycorrhizal roots isolated from forest sites. Enhanced methylamine uptake in the presence of the fungal symbiont was demonstrated. Homogeneous V-max values were found for axenic and detached mycorrhizas, whereas K-m values showed greater variations. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.},
  author       = {Javelle, Arnaud and Chalot, Michel and Söderström, Bengt and Botton, Bernard},
  issn         = {1574-6941},
  keyword      = {Ammonium/methylamine uptake,Kinetic experiment,Mycorrhiza,Paxillus involutus},
  language     = {eng},
  number       = {4},
  pages        = {355--366},
  publisher    = {Elsevier},
  series       = {FEMS Microbiology Ecology},
  title        = {Ammonium and methylamine transport by the ectomycorrhizal fungus Paxillus involutus and ectomycorrhizas},
  url          = {http://dx.doi.org/10.1111/j.1574-6941.1999.tb00663.x},
  volume       = {30},
  year         = {1999},
}