Revival of the Species Streptococcus thermophilus (ex Orla-Jensen, 1919) nom. rev.

Schleifer, Karl Heinz; Ehrmann, M. A.; Krusch, U.; Neve, Horst

doi:10.1016/s0723-2020(11)80314-0

Cited by 69 publications

(30 citation statements)

References 9 publications

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“…Furthermore, examination of each locus separately showed that S. thermophilus and the two commensal streptococci have no alleles in common. These results confirm the status of S. thermophilus as a distinct species (35).…”

Section: Discussionsupporting

confidence: 85%

“…For several years, S. thermophilus was classified as an S. salivarius subspecies (Streptococcus salivarius ssp. thermophilus) before regaining full species status based on DNA-DNA reassociation experiments (35). Recently, a population genetic analysis using multilocus sequence typing (MLST) was performed to better understand the phylogenetic relationship between S. salivarius and S. vestibularis and assess the genetic diversity within each species.…”

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confidence: 99%

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Emergence of a Cell Wall Protease in the Streptococcus thermophilus Population

Delorme

Bartholini

Bolotine

et al. 2010

Appl Environ Microbiol

106

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Streptococcus thermophilus is perceived as a recently emerged food bacterium that evolved from a commensal ancestor by loss and gain of functions. Here, we provide data allowing a better understanding of this evolutionary scheme. A multilocus sequence typing approach that we developed showed that S. thermophilus diverges significantly from its potential ancestors of the salivarius group and displays a low level of allelic variability, confirming its likely recent emergence. An analysis of the origin and dissemination of the prtS gene was carried out within this evolutionary scheme. This gene encodes a protease that allows better growth in milk by facilitating casein breakdown to supply amino acids. The S. thermophilus protease exhibits 95% identity to the animal Streptococcus suis protein PrtS. Genomic analysis showed that prtS is part of an island flanked by two tandem insertion sequence elements and containing three other genes which present the best identities and synteny with the S. suis genome. These data indicate a potential origin for this "ecological" island in a species closely related to S. suis. The analysis of the distribution of the prtS gene in S. thermophilus showed that the gene is infrequent in historical collections but frequent in recent industrial ones. Moreover, this "ecological" island conferring an important metabolic trait for milk adaptation appears to have disseminated by lateral transfer in the S. thermophilus population. Taken together, these data support an evolutionary scheme of S. thermophilus where gene acquisition and selection by food producers are determining factors. The source and impact of genes acquired by horizontal gene transfer on the physiology and safety of strains should be addressed.

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Section: Discussionsupporting

confidence: 85%

mentioning

confidence: 99%

Emergence of a Cell Wall Protease in the Streptococcus thermophilus Population

Delorme

Bartholini

Bolotine

et al. 2010

Appl Environ Microbiol

106

View full text Add to dashboard Cite

show abstract

“…An example of this evolutionary trend is represented by the milkadapted Streptococcus thermophilus and the closest phylogenetic neighbor Streptococcus salivarius. S. salivarius is an inhabitant of the oral cavity of mammals, and, despite the high-level phylogenetic relationship with S. thermophilus, the two species show extremely different carbohydrate utilization patterns, with only a few sugars utilized by the latter (46). The predicted Bifidobacterium ancestor would have been a microaerophile or facultative aerobe, which is reflected by the loss of the genes specifying the electron chain transport cytochrome bd subunits and particular enzymes (i.e., catalase and superoxide dismutase), which allow removal of toxic products that arise as a result of oxygen-mediated respiration (predicted to be present in members of the B. asteroides phylogenetic group).…”

Section: Resultsmentioning

confidence: 99%

Genomic Encyclopedia of Type Strains of the Genus Bifidobacterium

Milani

Lugli

Duranti

et al. 2014

Appl Environ Microbiol

217

225

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e Bifidobacteria represent one of the dominant microbial groups that are present in the gut of various animals, being particularly prevalent during the suckling stage of life of humans and other mammals. However, the overall genome structure of this group of microorganisms remains largely unexplored. Here, we sequenced the genomes of 42 representative (sub)species across the Bifidobacterium genus and used this information to explore the overall genetic picture of this bacterial group. Furthermore, the genomic data described here were used to reconstruct the evolutionary development of the Bifidobacterium genus. This reconstruction suggests that its evolution was substantially influenced by genetic adaptations to obtain access to glycans, thereby representing a common and potent evolutionary force in shaping bifidobacterial genomes.

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“…S. thermophilus and Streptococcus salivarius were shown to be closely related (S. thermophilus was formerly named S. salivarius subsp. thermophilus) but distinct enough to belong to different species (4,50). Thus, in this paper, the species was named S. thermophilus.…”

Section: Methodsmentioning

confidence: 99%

Physical and genetic map of Streptococcus thermophilus A054

Roussel¹,

Pébay²,

Guédon³

et al. 1994

J Bacteriol

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The three restriction endonucleases Sfil, BssHl, and SmaI were found to generate fragments with suitable size distributions for mapping the genome of Streptococcus thermophilus A054. A total of 5, 8, and 24 fragments were produced with SfiI, BssHI, and SmaI, respectively. An average genome size of 1,824 kb was determined by summing the total fragment sizes obtained by digestions with these three enzymes. Partial and multiple digestions of genomic DNA in conjunction with Southern hybridization were used to map SfI, BssHII, and SmaI fragments. All restriction fragments were arranged in a unique circular chromosome. Southern hybridization analysis with specific probes allowed 23 genetic markers to be located on the restriction map. Among them, six rrn loci were precisely located. The area of the chromosome containing the ribosomal operons was further detailed by mapping some of the ApaI and SgrAI sites. Comparison of macrorestriction patterns from three clones derived from strain A054 revealed two variable regions in the chromosome. One was associated with the tandem rinD and rnnE loci, and the other was mapped in the region of the lactose operon.Streptococcus thermophilus is an economically important lactic acid bacterium used in the manufacture of yoghurt and some hard cheeses. It is a gram-positive, facultative anaerobic microorganism that is exclusively isolated from milk and fermented dairy products. Despite its importance in the dairy industry, genetic studies of S. thermophilus have been limited until recently. To date, basic methods of gene transfer by transformation, transduction, or conjugative mobilization have been reported (34). Several genes have been cloned and analyzed, including genes involved in glucide metabolism (lacZ, lacS, galE, galM, and ldh [5,25,43,44,51]) and DNA recombination (recA [15]), ribosomal sequences (4, 23, 38), and the aspartate racemase gene (62). A marked restriction polymorphism has been detected between different strains of this species by analysis of hybridization patterns obtained with a species-specific probe (13) and with probes by genes coding for rRNA (38). Despite the availability of gene transfer systems and cloned genes, the structure and organization of the S. thermophilus genome are not well defined.Pulsed-field gel electrophoresis (PFGE) (9, 52) has proved to be an efficient method for genome size estimation and construction of chromosomal maps, as well as being a useful tool for the characterization of bacterial species. Preliminary results from PFGE have indicated a genome size of 1.75 Mb for strain STi of S. thermophilus (31) and allowed restriction polymorphism within S. thermophilus to be observed (48).In this study, we used PFGE to estimate the size of the chromosome of S. thermophilus A054 and to construct a physical map by using the restriction enzymes SMaI, Sfil, BssHII, ApaI, and SgrAI. Hybridization probes were used to locate 23 genetic markers on the chromosomal map. Genetic polymorphism within strain A054 was analyzed by comparing the macrorestric...

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Revival of the Species Streptococcus thermophilus (ex Orla-Jensen, 1919) nom. rev.

Cited by 69 publications

References 9 publications

Emergence of a Cell Wall Protease in the Streptococcus thermophilus Population

Emergence of a Cell Wall Protease in the Streptococcus thermophilus Population

Genomic Encyclopedia of Type Strains of the Genus Bifidobacterium

Physical and genetic map of Streptococcus thermophilus A054

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