This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by García-Quintáns, N.
Right arrow Articles by López, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by García-Quintáns, N.
Right arrow Articles by López, P.
Agricola
Right arrow Articles by García-Quintáns, N.
Right arrow Articles by López, P.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, April 2008, p. 1988-1996, Vol. 74, No. 7
0099-2240/08/$08.00+0     doi:10.1128/AEM.01851-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Activation of the Diacetyl/Acetoin Pathway in Lactococcus lactis subsp. lactis bv. diacetylactis CRL264 by Acidic Growth{triangledown} ,{dagger}

Nieves García-Quintáns,1 Guillermo Repizo,2 Mauricio Martín,1 Christian Magni,2 and Paloma López1*

Departamento de Ciencia de Proteínas, Centro de Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain,1 Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina2

Received 9 August 2007/ Accepted 24 January 2008

Lactococcus lactis subsp. lactis bv. diacetylactis strains are aroma-producing organisms used in starter cultures for the elaboration of dairy products. This species is essentially a fermentative microorganism, which cometabolizes glucose and citrate to yield aroma compounds through the diacetyl/acetoin biosynthetic pathway. Our previous results have shown that under acidic growth Lactococcus bv. diacetylactis CRL264 expresses coordinately the genes responsible for citrate transport and its conversion into pyruvate. In the present work the impact of acidic growth on glucose, citrate, and pyruvate metabolism of Lactococcus bv. diacetylactis CRL264 has been investigated by proteomic analysis. The results indicated that acid growth triggers the conversion of citrate, but not glucose, into {alpha}-acetolactate via pyruvate. Moreover, they showed that low pH has no influence on levels of lactate dehydrogenase and pyruvate dehydrogenase. Therefore, the influence of external pH on regulation of the diacetyl/acetoin biosynthetic pathway in Lactococcus bv. diacetylactis CRL264 has been analyzed at the transcriptional level. Expression of the als, aldB, aldC, and butBA genes encoding the enzymes involved in conversion of pyruvate into aroma compounds has been investigated by primer extension, reverse transcription-PCR analysis, and transcriptional fusions. The results support that this biosynthetic pathway is induced at the transcriptional level by acidic growth conditions, presumably contributing to lactococcal pH homeostasis by synthesis of neutral compounds and by decreasing levels of pyruvate.

* Corresponding author. Mailing address: Departamento de Ciencia de Proteínas, Centro de Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain. Phone: (34) 918373112. Fax: (34) 915360432. E-mail: plg{at}cib.csic.es

{triangledown} Published ahead of print on 1 February 2008.

{dagger} Supplemental material for this article may be found at http://aem.asm.org/.

Applied and Environmental Microbiology, April 2008, p. 1988-1996, Vol. 74, No. 7
0099-2240/08/$08.00+0     doi:10.1128/AEM.01851-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Blancato, V. S., Repizo, G. D., Suarez, C. A., Magni, C. (2008). Transcriptional Regulation of the Citrate Gene Cluster of Enterococcus faecalis Involves the GntR Family Transcriptional Activator CitO. J. Bacteriol. 190: 7419-7430 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»