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Type: Journal article
Title: Regulation of neuraminidase expression in Streptococcus pneumoniae
Author: Gualdi, L.
Hayre, J.
Gerlini, A.
Bidossi, A.
Colomba, L.
Trappetti, C.
Pozzi, G.
Docquier, J.
Andrew, P.
Ricci, S.
Oggioni, M.
Citation: BMC Microbiology, 2012; 12(1):1-12
Publisher: BioMed Central Ltd.
Issue Date: 2012
ISSN: 1471-2180
Statement of
Luciana Gualdi, Jasvinder Kaur Hayre, Alice Gerlini, Alessandro Bidossi, Leonarda Colomba, Claudia Trappetti, Gianni Pozzi, Jean-Denis Docquier, Peter Andrew, Susanna Ricci and Marco R Oggioni
Abstract: BACKGROUND: Sialic acid (N-acetylneuraminic acid; NeuNAc) is one of the most important carbohydrates for Streptococcus pneumoniae due of its role as a carbon and energy source, receptor for adhesion and invasion and molecular signal for promotion of biofilm formation, nasopharyngeal carriage and invasion of the lung. RESULTS: In this work, NeuNAc and its metabolic derivative N-acetyl mannosamine (ManNAc) were used to analyze regulatory mechanisms of the neuraminidase locus expression. Genomic and metabolic comparison to Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii and Streptococcus sanguinis elucidates the metabolic association of the two amino sugars to different parts of the locus coding for the two main pneumococcal neuraminidases and confirms the substrate specificity of the respective ABC transporters. Quantitative gene expression analysis shows repression of the locus by glucose and induction of all predicted transcriptional units by ManNAc and NeuNAc, each inducing with higher efficiency the operon encoding for the transporter with higher specificity for the respective amino sugar. Cytofluorimetric analysis demonstrated enhanced surface exposure of NanA on pneumococci grown in NeuNAc and ManNAc and an activity assay allowed to quantify approximately twelve times as much neuraminidase activity on induced cells as opposed to glucose grown cells. CONCLUSIONS: The present data increase the understanding of metabolic regulation of the nanAB locus and indicate that experiments aimed at the elucidation of the relevance of neuraminidases in pneumococcal virulence should possibly not be carried out on bacteria grown in glucose containing media.
Keywords: Sialic acid; Metabolic regulation; Carbon catabolite repression
Description: The electronic version of this article is the complete one and can be found online at: Extent: 12p.
Rights: © 2012 Gualdi et al.; licensee BioMed Central Ltd.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
RMID: 0020123505
DOI: 10.1186/1471-2180-12-200
Appears in Collections:Molecular and Biomedical Science publications

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