16S-23S and 23S-5S intergenic spacer regions of Streptococcus thermophilus and Streptococcus salivarius, primary and secondary structure

1995 ◽  
Vol 31 (5) ◽  
pp. 270-278 ◽  
Author(s):  
Mohamed Nour ◽  
Afaf Naimi ◽  
Genevi�ve Beck ◽  
Christine Branlant
Keyword(s):  
Secondary Structure ◽  
Intergenic Spacer ◽  
Streptococcus Thermophilus ◽  
Streptococcus Salivarius

25S-18S rDNA intergenic spacer ofNicotiana sylvestris (Solanaceae): Primary and secondary structure analysis

1999 ◽  
Vol 218 (1-2) ◽  
pp. 89-97 ◽  
Author(s):  
R. A. Volkov ◽  
A. Bachmair ◽  
I. I. Panchuk ◽  
S. S. Kostyshyn ◽  
D. Schweizer
Keyword(s):  
Secondary Structure ◽  
Structure Analysis ◽  
18S Rdna ◽  
Intergenic Spacer ◽  
Secondary Structure Analysis ◽  
Rdna Intergenic Spacer

scholarly journals Role of galK and galM in Galactose Metabolism by Streptococcus thermophilus

2007 ◽  
Vol 74 (4) ◽  
pp. 1264-1267 ◽  
Author(s):  
Katy Vaillancourt ◽  
Nathalie Bédard ◽  
Christian Bart ◽  
Mélanie Tessier ◽  
Gilles Robitaille ◽  
...  
Keyword(s):  
Streptococcus Thermophilus ◽  
Streptococcus Salivarius ◽  
Galactose Metabolism

ABSTRACT Streptococcus thermophilus is unable to metabolize the galactose moiety of lactose. In this paper, we show that a transformant of S. thermophilus SMQ-301 expressing Streptococcus salivarius galK and galM was able to grow on galactose and expelled at least twofold less galactose into the medium during growth on lactose.

scholarly journals Galactose and Lactose Genes from the Galactose-Positive Bacterium Streptococcus salivarius and the Phylogenetically Related Galactose-Negative Bacterium Streptococcus thermophilus: Organization, Sequence, Transcription, and Activity of the gal Gene Products

2002 ◽  
Vol 184 (3) ◽  
pp. 785-793 ◽  
Author(s):  
Katy Vaillancourt ◽  
Sylvain Moineau ◽  
Michel Frenette ◽  
Christian Lessard ◽  
Christian Vadeboncoeur
Keyword(s):  
Gene Cluster ◽  
Streptococcus Thermophilus ◽  
Gene Clusters ◽  
Northern Blotting ◽  
Gene Products ◽  
Streptococcus Salivarius ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Identical Nucleotide

ABSTRACT Streptococcus salivarius is a lactose- and galactose-positive bacterium that is phylogenetically closely related to Streptococcus thermophilus, a bacterium that metabolizes lactose but not galactose. In this paper, we report a comparative characterization of the S. salivarius and S. thermophilus gal-lac gene clusters. The clusters have the same organization with the order galR (codes for a transcriptional regulator and is transcribed in the opposite direction), galK (galactokinase), galT (galactose-1-P uridylyltransferase), galE (UDP-glucose 4-epimerase), galM (galactose mutarotase), lacS (lactose transporter), and lacZ (β-galactosidase). An analysis of the nucleotide sequence as well as Northern blotting and primer extension experiments revealed the presence of four promoters located upstream from galR, the gal operon, galM, and the lac operon of S. salivarius. Putative promoters with virtually identical nucleotide sequences were found at the same positions in the S. thermophilus gal-lac gene cluster. An additional putative internal promoter at the 3′ end of galT was found in S. thermophilus but not in S. salivarius. The results clearly indicated that the gal-lac gene cluster was efficiently transcribed in both species. The Shine-Dalgarno sequences of galT and galE were identical in both species, whereas the ribosome binding site of S. thermophilus galK differed from that of S. salivarius by two nucleotides, suggesting that the S. thermophilus galK gene might be poorly translated. This was confirmed by measurements of enzyme activities.

scholarly journals A Novel Pheromone Quorum-Sensing System Controls the Development of Natural Competence in Streptococcus thermophilus and Streptococcus salivarius

2009 ◽  
Vol 192 (5) ◽  
pp. 1444-1454 ◽  
Author(s):  
Laetitia Fontaine ◽  
Céline Boutry ◽  
Marie Henry de Frahan ◽  
Brigitte Delplace ◽  
Christophe Fremaux ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Response Regulator ◽  
Streptococcus Thermophilus ◽  
Streptococcus Salivarius ◽  
Gene Encoding ◽  
Component System ◽  
Sensing System ◽  
Quorum Sensing System ◽  
Streptococcal Species ◽  
Transcriptional Induction

ABSTRACT In streptococcal species, the key step of competence development is the transcriptional induction of comX, which encodes the alternative sigma factor σX, which positively regulates genes necessary for DNA transformation. In Streptococcus species belonging to the mitis and mutans groups, induction of comX relies on the activation of a three-component system consisting of a secreted pheromone, a histidine kinase, and a response regulator. In Streptococcus thermophilus, a species belonging to the salivarius group, the oligopeptide transporter Ami is essential for comX expression under competence-inducing conditions. This suggests a different regulation pathway of competence based on the production and reimportation of a signal peptide. The objective of our work was to identify the main actors involved in the early steps of comX induction in S. thermophilus LMD-9. Using a transcriptomic approach, four highly induced early competence operons were identified. Among them, we found a Rgg-like regulator (Ster_0316) associated with a nonannotated gene encoding a 24-amino-acid hydrophobic peptide (Shp0316). Through genetic deletions, we showed that these two genes are essential for comX induction. Moreover, addition to the medium of synthetic peptides derived from the C-terminal part of Shp0316 restored comX induction and transformation of a Shp0316-deficient strain. These peptides also induced competence in S. thermophilus and Streptococcus salivarius strains that are poorly transformable or not transformable. Altogether, our results show that Ster_0316 and Shp0316, renamed ComRS, are the two members of a novel quorum-sensing system responsible for comX induction in species from the salivarius group, which differs from the classical phosphorelay three-component system identified previously in streptococci.

scholarly journals Streptococcus thermophilus: To Survive, or Not to Survive the Gastrointestinal Tract, That Is the Question!

Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2175
Author(s):  
Anđela Martinović ◽  
Riccardo Cocuzzi ◽  
Stefania Arioli ◽  
Diego Mora
Keyword(s):  
Gastrointestinal Tract ◽  
World Wide ◽  
Intervention Studies ◽  
Scientific Literature ◽  
Scientific Evidence ◽  
Streptococcus Thermophilus ◽  
Streptococcus Salivarius ◽  
Human Gastrointestinal Tract ◽  
Scientific Validity ◽  
Stool Samples

The probiotic market is increasing world-wide as well as the number of products marketed as probiotics. Among the latter, many products contain Streptococcus thermophilus strains at several dosages. However, the scientific evidence that should support the probiotic status of those S. thermophilus strains is often contradictory. This review analyses the scientific literature aimed to assess the ability of S. thermophilus strains to survive the human gastrointestinal tract by discussing the scientific validity of the methods applied for the bacterial recovery and identification from stool samples. This review highlights that in most of the intervention studies reviewed, the identification of S. thermophilus strains from stools was not carried out with the necessary taxonomic accuracy to avoid their misidentification with Streptococcus salivarius, a common human commensal and a species phylogenetically close to S. thermophilus. Moreover, this review highlights how critical the accurate taxonomic identification of S. thermophilus in metagenomics-based studies can be.

scholarly journals Phosphorylation of Streptococcus salivarius Lactose Permease (LacS) by HPr(His∼P) and HPr(Ser-P)(His∼P) and Effects on Growth

2003 ◽  
Vol 185 (23) ◽  
pp. 6764-6772 ◽  
Author(s):  
Christian Lessard ◽  
Armelle Cochu ◽  
Jean-Dominique Lemay ◽  
Denis Roy ◽  
Katy Vaillancourt ◽  
...  
Keyword(s):  
Streptococcus Thermophilus ◽  
Lactose Permease ◽  
Streptococcus Salivarius ◽  
Phosphorylated Form ◽  
Generation Times ◽  
Related Organism ◽  
Oral Bacterium ◽  
Mutant Strains ◽  
Enzyme I ◽  
Phosphotransferase Transport System

ABSTRACT The oral bacterium Streptococcus salivarius takes up lactose via a transporter called LacS that shares 95% identity with the LacS from Streptococcus thermophilus, a phylogenetically closely related organism. S. thermophilus releases galactose into the medium during growth on lactose. Expulsion of galactose is mediated via LacS and stimulated by phosphorylation of the transporter by HPr(His∼P), a phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS). Unlike S. thermophilus, S. salivarius grew on lactose without expelling galactose and took up galactose and lactose concomitantly when it is grown in a medium containing both sugars. Analysis of the C-terminal end of S. salivarius LacS revealed a IIA-like domain (IIALacS) almost identical to the IIA domain of S. thermophilus LacS. Experiments performed with purified proteins showed that S. salivarius IIALacS was reversibly phosphorylated on a histidine residue at position 552 not only by HPr(His∼P) but also by HPr(Ser-P)(His∼P), a doubly phosphorylated form of HPr present in large amounts in rapidly growing S. salivarius cells. Two other major S. salivarius PTS proteins, IIABL Man and IIABH Man, were unable to phosphorylate IIALacS. The effect of LacS phosphorylation on growth was studied with strain G71, an S. salivarius enzyme I-negative mutant that cannot synthesize HPr(His∼P) or HPr(Ser-P)(His∼P). These results indicated that (i) the wild-type and mutant strains had identical generation times on lactose, (ii) neither strain expelled galactose during growth on lactose, (iii) both strains metabolized lactose and galactose concomitantly when grown in a medium containing both sugars, and (iv) the growth of the mutant was slightly reduced on galactose.

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