Glutamate uptake in Lactobacillus delbrueckii subsp. bulgaricus CNRZ 208 and its enhancement by a combination of Mn2+ and Mg2
Aims: To demonstrate the mechanism of glutamate uptake in the dairy strain Lactobacillus delbrueckii subsp. bulgaricus CNRZ 208, and to characterize key aspects of the system . Methods and Results: Glutamate uptake proceeded via an active transport system requiring an exogenous source of energy. The...
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Published in | Letters in applied microbiology Vol. 35; no. 5; pp. 428 - 432 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Blackwell Science Ltd
01.01.2002
Blackwell Science |
Subjects | |
Online Access | Get full text |
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Summary: | Aims:
To demonstrate the mechanism of glutamate uptake in the dairy strain
Lactobacillus delbrueckii
subsp.
bulgaricus
CNRZ 208, and to characterize key aspects of the system
.
Methods and Results:
Glutamate uptake proceeded via an active transport system requiring an exogenous source of energy. The system also transported aspartate and glutamine. It was unique, with a K
t
of 2·8 µmol l
−1
and a V
max
of 900 µmol s
−1
(g dry weight)
−1
. The activity was optimal at pH 7·3 and 50°C, was independent of the glutamate charge, and was enhanced by Mn
2+
+ Mg
2+
in combination. Inhibition of the activity by uncouplers and ionophores showed that transport was driven by an ATP‐dependent mechanism involving the proton‐motive force. This inhibition was partially abolished in the presence of both Mn
2+
and Mg
2+ .
Conclusions:
We demonstrated for the first time that an active transport system governs the uptake of the essential amino acid glutamate in
Lact. delbrueckii
subsp.
bulgaricus
CNRZ 208, the activity of which is enhanced by a combination of Mn
2+
and Mg
2+ .
Significance and Impact of the Study:
The potential of the findings is discussed with reference to the growth of
Lact. delbrueckii
subsp.
bulgaricus in mixed‐strain cultures for the dairy industry. |
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Bibliography: | Present addresses: G. Savoy de Giori, 1 Centro de Referencia para Lactobacilos (CERELA), Chacabuco 145, 4000 Tucuman, Argentina; and M. Ferchichi, Fromagerie des Chaumes, BP 5, 64110 Jurançon, France. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0266-8254 1472-765X 1365-2673 |
DOI: | 10.1046/j.1472-765X.2002.01208.x |