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Protonmotive force driven 6-deoxyglucose uptake by the oral pathogen, Streptococcus mutans Ingbritt

Protonmotive force driven 6-deoxyglucose uptake by the oral pathogen, Streptococcus mutans Ingbritt
Protonmotive force driven 6-deoxyglucose uptake by the oral pathogen, Streptococcus mutans Ingbritt

Streptococcus mutans Ingbritt was grown in glucose-excess continuous culture to repress the glucose phosphoenolpyruvate phosphotransferase system (PTS) and allow investigation of the alternative glucose process using the non-PTS substrate, (3H) 6-deoxyglucose. After correcting for non-specific adsorption to inactivated cells, the radiolabelled glucose analogue was found to be concentrated approximately 4.3-fold intracellularly by bacteria incubated in 100 mM Tris-citrate buffer, pH 7.0. Mercaptoethanol or KCl enhanced 6-deoxyglucose uptake, enabling it to be concentrated internally by at least 8-fold, but NaCl was inhibitory to its transport. Initial uptake was antagonised by glucose but not 2-deoxyglucose. Evidence that 6-deoxyglucose transport was driven by protonmotive force (Δp) was obtained by inhibiting its uptake with the protonophores, 2,4-dinitrophenol, carbonylcyanide m-chlorophenylhydrazine, gramicidin and nigericin, and the electrical potential difference (ΔΨ) dissipator, KSCN. The membrane ATPase inhibitor, N,N1-dicyclohexyl carbodiimide, also reduced 6-deoxyglucose uptake as did 100 mM lactate. In combination, these two inhibitors completely abolished 6-deoxyglucose transport. This suggests that the driving force for 6-deoxyglucose uptake is electrogenic, involving both the transmembrane pH gradient (ΔpH) and ΔΨ. ATP hydrolysis, catalysed by the ATPase, and lactate excretion might be important contributors to ΔpH.

Chemostat culture, Dental disease, Protonmotive force, Streptococcus mutans, Sugar transport
0302-8933
118-124
Keevil, C. W.
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
McDermid, A. S.
34686047-11ba-41da-884d-1dc41fa7024b
Marsh, P. D.
9d226405-bfd2-432b-ac22-ea619f706805
Ellwood, D. C.
a7dc8f2a-f392-42b4-a022-fa5a58cf6be6
Keevil, C. W.
cb7de0a7-ce33-4cfa-af52-07f99e5650eb
McDermid, A. S.
34686047-11ba-41da-884d-1dc41fa7024b
Marsh, P. D.
9d226405-bfd2-432b-ac22-ea619f706805
Ellwood, D. C.
a7dc8f2a-f392-42b4-a022-fa5a58cf6be6

Keevil, C. W., McDermid, A. S., Marsh, P. D. and Ellwood, D. C. (1986) Protonmotive force driven 6-deoxyglucose uptake by the oral pathogen, Streptococcus mutans Ingbritt. Archives of Microbiology, 146 (2), 118-124. (doi:10.1007/BF00402337).

Record type: Article

Abstract

Streptococcus mutans Ingbritt was grown in glucose-excess continuous culture to repress the glucose phosphoenolpyruvate phosphotransferase system (PTS) and allow investigation of the alternative glucose process using the non-PTS substrate, (3H) 6-deoxyglucose. After correcting for non-specific adsorption to inactivated cells, the radiolabelled glucose analogue was found to be concentrated approximately 4.3-fold intracellularly by bacteria incubated in 100 mM Tris-citrate buffer, pH 7.0. Mercaptoethanol or KCl enhanced 6-deoxyglucose uptake, enabling it to be concentrated internally by at least 8-fold, but NaCl was inhibitory to its transport. Initial uptake was antagonised by glucose but not 2-deoxyglucose. Evidence that 6-deoxyglucose transport was driven by protonmotive force (Δp) was obtained by inhibiting its uptake with the protonophores, 2,4-dinitrophenol, carbonylcyanide m-chlorophenylhydrazine, gramicidin and nigericin, and the electrical potential difference (ΔΨ) dissipator, KSCN. The membrane ATPase inhibitor, N,N1-dicyclohexyl carbodiimide, also reduced 6-deoxyglucose uptake as did 100 mM lactate. In combination, these two inhibitors completely abolished 6-deoxyglucose transport. This suggests that the driving force for 6-deoxyglucose uptake is electrogenic, involving both the transmembrane pH gradient (ΔpH) and ΔΨ. ATP hydrolysis, catalysed by the ATPase, and lactate excretion might be important contributors to ΔpH.

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More information

Published date: 1 November 1986
Keywords: Chemostat culture, Dental disease, Protonmotive force, Streptococcus mutans, Sugar transport

Identifiers

Local EPrints ID: 431319
URI: http://eprints.soton.ac.uk/id/eprint/431319
ISSN: 0302-8933
PURE UUID: 4eeff4ce-f10e-40df-be80-1cdf3d20e1d4
ORCID for C. W. Keevil: ORCID iD orcid.org/0000-0003-1917-7706

Catalogue record

Date deposited: 29 May 2019 16:30
Last modified: 30 May 2019 00:36

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