Explore the vast range of titles available.

This study evaluated the effect of a partly fermented infant formula (using the bacterial strains Bifidobacterium breve C50 and Streptococcus thermophilus 065) with a specific prebiotic mixture (short-chain galacto-oligosaccharides (scGOS) and long-chain fructo-oligosaccharides (lcFOS; 9:1)) on the incidence of gastrointestinal symptoms, stool characteristics, sleeping and crying behaviour, growth adequacy and safety. Two-hundred infants ≤28 days of age were assigned either to experimental infant formula containing 30% fermented formula and 0.8 g/100 mL scGOS/lcFOS or to non-fermented control infant formula without scGOS/lcFOS. A group of breastfed infants served as a reference. No relevant differences in parent-reported gastrointestinal symptoms were observed. Stool consistency was softer in the experimental versus control group with values closer to the breastfed reference group. Daily weight gain was equivalent for both formula groups (0.5 SD margins) with growth outcomes close to breastfed infants. No clinically relevant differences in adverse events were observed, apart from a lower investigator-reported prevalence of infantile colic in the experimental versus control group (1.1% vs. 8.7%; p < 0.02). Both study formulae are well-tolerated, support an adequate infant growth and are safe for use in healthy term infants. Compared to the control formula, the partly fermented formula with prebiotics induces stool consistencies closer to breastfed infants.

Lactic acid bacteria (LAB) contribute to human health; however, the probiotic properties vary among strains classified into the same species. The primary objective of this study was to evaluate the effects of yogurts made by different types of LAB on the gastrointestinal system. The yogurts were also evaluated by measuring serum lipid contents and liver functional indicators as a secondary objective. Healthy human adults (n = 68) with some complaints with regard to intestinal health, including constipation and diarrhea, were randomly assigned to receive one of three types of yogurt in a double-blind manner: type A, a yogurt made by plant-derived LAB (mainly Lactobacillus [Lb.] plantarum SN35N); type B, a yogurt made by plant-derived LAB (mainly Lb. plantarum SN13T); and type C, a yogurt made by animal-derived LAB (mainly Lactococcus lactis A6 and Streptococcus thermophilus 510) as a control. The subjects consumed 100 g of yogurt daily for 6 wk. Data were collected from clinical visits at 2-wk intervals and by diaries used to record defecation and health conditions. Drastic and constant increments of defecation frequency in subjects with constipation were observed with type A and B yogurts but not with type C yogurt. Type B and C yogurts resulted in decreases in total and low-density lipoprotein cholesterol. The serum concentrations of liver functional parameters were improved by the type B yogurt (12–25% reduction). The present study suggests that Lb. plantarum SN13T exhibits a superior probiotic effect on constipation in addition to improving the serum lipid contents and liver function.

Type III CRISPR-Cas systems in prokaryotes provide immunity against invading nucleic acids through the coordinated degradation of transcriptionally active DNA and its transcripts by the Csm effector complex. The Cas10 subunit of the complex contains an HD nuclease domain that is responsible for DNA degradation and two Palm domains with elusive functions. In addition, Csm6, a ribonuclease that is not part of the complex, is also required to provide full immunity. We show here that target RNA binding by the Csm effector complex of Streptococcus thermophilus triggers Cas10 to synthesize cyclic oligoadenylates (cA n ; n = 2 to 6) by means of the Palm domains. Acting as signaling molecules, cyclic oligoadenylates bind Csm6 to activate its nonspecific RNA degradation. This cyclic oligoadenylate–based signaling pathway coordinates different components of CRISPR-Cas to prevent phage infection and propagation.

Background Streptococcus thermophilus is a Gram-positive bacterium widely used as starter in the dairy industry as well as in many traditional fermented products. In addition to its technological importance, it has also gained interest in recent years as beneficial bacterium due to human health-promoting functionalities. The objective of this study was to inventory the main health-promoting properties of S. thermophilus and to study their intra-species diversity at the genomic and genetic level within a collection of representative strains. Results In this study various health-related functions were analyzed at the genome level from 79 genome sequences of strains isolated over a long time period from diverse products and different geographic locations. While some functions are widely conserved among isolates (e.g., degradation of lactose, folate production) suggesting their central physiological and ecological role for the species, others including the tagatose-6-phosphate pathway involved in the catabolism of galactose, and the production of bioactive peptides and gamma-aminobutyric acid are strain-specific. Most of these strain-specific health-promoting properties seems to have been acquired via horizontal gene transfer events. The genetic basis for the phenotypic diversity between strains for some health related traits have also been investigated. For instance, substitutions in the galK promoter region correlate with the ability of some strains to catabolize galactose via the Leloir pathway. Finally, the low occurrence in S. thermophilus genomes of genes coding for biogenic amine production and antibiotic resistance is also a contributing factor to its safety status. Conclusions The natural intra-species diversity of S. thermophilus , therefore, represents an interesting source for innovation in the field of fermented products enriched for healthy components that can be exploited to improve human health. A better knowledge of the health-promoting properties and their genomic and genetic diversity within the species may facilitate the selection and application of strains for specific biotechnological and human health-promoting purpose. Moreover, by pointing out that a substantial part of its functional potential still defies us, our work opens the way to uncover additional health-related functions through the intra-species diversity exploration of S. thermophilus by comparative genomics approaches.

Thirty-four strains of lactic acid bacteria (seven Bifidobacterium , 11 Lactobacillus , six Lactococcus , and 10 Streptococcus thermophilus ) were assayed in vitro for antioxidant activity against ascorbic and linolenic acid oxidation (TAA AA and TAA LA ), trolox-equivalent antioxidant capacity (TEAC), intracellular glutathione (TGSH), and superoxide dismutase (SOD). Wide dispersion of each of TAA AA , TAA LA , TEAC, TGSH, and SOD occurred within bacterial groups, indicating that antioxidative properties are strain specific. The strains Bifidobacterium animalis subsp. lactis DSMZ 23032, Lactobacillus acidophilus DSMZ 23033, and Lactobacillus brevis DSMZ 23034 exhibited among the highest TAA AA , TAA LA , TEAC, and TGSH values within the lactobacilli and bifidobacteria. These strains were used to prepare a potentially antioxidative probiotic formulation, which was administered to rats at the dose of 10 7 , 10 8 , and 10 9  cfu/day for 18 days. The probiotic strains colonized the colon of the rats during the trial and promoted intestinal saccharolytic metabolism. The analysis of plasma antioxidant activity, reactive oxygen molecules level, and glutathione concentration, revealed that, when administered at doses of at least 10 8  cfu/day, the antioxidant mixture effectively reduced doxorubicin-induced oxidative stress. Probiotic strains which are capable to limit excessive amounts of reactive radicals in vivo may contribute to prevent and control several diseases associated with oxidative stress.

Type II CRISPR-Cas systems introduce double-strand breaks into DNA of invading genetic material and use DNA fragments to acquire novel spacers during adaptation. These breaks can be the substrate of several DNA repair pathways, paving the way for interactions. We report that non-homologous end-joining (NHEJ) and type II-A CRISPR-Cas systems only co-occur once among 5563 fully sequenced prokaryotic genomes. We investigated experimentally the possible molecular interactions using the NHEJ pathway from Bacillus subtilis and the type II-A CRISPR-Cas systems from Streptococcus thermophilus and Streptococcus pyogenes . Our results suggest that the NHEJ system has no effect on CRISPR immunity. On the other hand, we provide evidence for the inhibition of NHEJ repair by the Csn2 protein. Our findings give insights on the complex interactions between CRISPR-Cas systems and repair mechanisms in bacteria, contributing to explain the scattered distribution of CRISPR-Cas systems in bacterial genome. The double-strand breaks generated by CRISPR-Cas systems are the target of multiple DNA repair pathways. Here the authors find incompatibility between NHEJ and type II-A CRISPR-Cas systems due to Csn2 mediated inhibition of end-joining.

Streptococcus thermophilus is the most important thermophilic dairy starter, and is widely used in the dairy industry. Streptococcus thermophilus exopolysaccharides received wide attention over recent decades, because they can improve the properties of the dairy product and confer beneficial health effects. The understanding of the regulatory and biosynthetic mechanisms of EPS will improve the EPS biosynthesis, increase the productivity of EPSs, and develop EPSs with desirable properties. The structure of EPSs is the focus of this study. Revealing the structure–function relationship can lead to increase the knowledge base and from there to increased research of EPS. The EPS yield is a key limiting factor in the research and utilization of EPS. In the present review, biosynthetic pathways and genetics of S. thermophilus EPSs were described and reviewed. At the same time, functional properties and applications of EPS, and strategies for enhancement of EPS production are discussed.

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.

Lactobacillus delbrueckii subsp. bulgaricus ( L. bulgaricus ) and Streptococcus thermophilus ( S. thermophilus ) are commonly used starters in milk fermentation. Fermentation experiments revealed that L. bulgaricus-S. thermophilus interactions ( LbSt I ) substantially impact dairy product quality and production. Traditional biological humidity experiments are time-consuming and labor-intensive in screening interaction combinations, an artificial intelligence-based method for screening interactive starter combinations is necessary. However, in the current research on artificial intelligence based interaction prediction in the field of bioinformatics, most successful models adopt supervised learning methods, and there is a lack of research on interaction prediction with only a small number of labeled samples. Hence, this study aimed to develop a semi-supervised learning framework for predicting LbSt I using genomic data from 362 isolates (181 per species). The framework consisted of a two-part model: a co-clustering prediction model (based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) dataset) and a Laplacian regularized least squares prediction model (based on K-mer analysis and gene composition of all isolates datasets). To enhance accuracy, we integrated the separate outcomes produced by each component of the two-part model to generate the ultimate LbSt I prediction results, which were verified through milk fermentation experiments. Validation through milk fermentation experiments confirmed a high precision rate of 85% (17/20; validated with 20 randomly selected combinations of expected interacting isolates). Our data suggest that the biosynthetic pathways of cysteine, riboflavin, teichoic acid, and exopolysaccharides, as well as the ATP-binding cassette transport systems, contribute to the mutualistic relationship between these starter bacteria during milk fermentation. However, this finding requires further experimental verification. The presented model and data are valuable resources for academics and industry professionals interested in screening dairy starter cultures and understanding their interactions.

Background CodY (Control of dppY) is a global transcriptional regulator of Streptococcus thermophilus (ST). In this study, we utilized a S. thermophilus codY gene deletion mutant strain to explore metabolites that may affect the oxidative-stress resistance of Lactobacillus delbrueckii subsp. bulgaricus . The context of this research is to understand the role of CodY in the interaction between S. thermophilus and L. delbrueckii , particularly focusing on the impact of CodY on the oxidative-stress resistance of L. delbrueckii . Results Firstly, the ST-1Δ codY mutant strain was constructed by the knockout technique. We found that codY gene deletion significantly reduced the growth rate and resistance to oxidative stress of L. delbrueckii in co-culture, with a decrease in viable bacterial count to 5.26 ± 0.04 log(cfu/mL), and a decrease in survival by 15% and 25% under 5 mM and 10 mM H 2 O 2 stress, respectively. Metabolites were comprehensively analyzed under three different culture conditions, and we identified 35 differentiated metabolites associated with CodY regulation. These metabolites were screened by their significant differential metabolite expression folds (up- or down-regulation) under different culture conditions, and Variable Importance in Projection (VIP) values assessed their significance, fold changes, and P values. Further, we identified six compounds, including lysine, 4-hydroxyphenylacetic acid, cycloleucine, glycine-L-lysine, 3-hydroxyphenylacetic acid, and N 6 -acetyl-L-lysine, which significantly enhanced the oxidative-stress resistance of L. delbrueckii . The viable counts of L. delbrueckii were increased by 7.73%, 6.49%, 4.27%, 3.62%, 2.12%, and 1.38%, respectively, in the medium supplemented with these substances under the stress of 10 mM H 2 O 2 . Conclusions The study results are important for understanding the synergistic effect of the two bacteria during fermentation and their response to environmental stresses. The findings provide insights into the role of CodY in modulating the oxidative-stress resistance of L. delbrueckii and highlight the potential of identified metabolites to enhance the performance of this bacterium under stress conditions. This could have implications for the development of strategies to improve the robustness of industrial fermentation processes involving these bacteria.