WorldWideScience

Sample records for alkalithermophile natranaerobius thermophilus

  1. Risposta adattativa allo stress in Streptococcus thermophilus

    OpenAIRE

    Asterinou, Kleopatra

    2009-01-01

    Streptococcus thermophilus è uno dei batteri lattici più utilizzati nell’ industria alimentare per la produzione di cibi fermentati. In questo lavoro sono stati isolati mutanti di S. thermophilus di alcuni geni noti dalla letteratura per essere indotti in condizioni di stress di natura acida, termica ed osmotica, e di alcuni geni che codificano per prodotti implicati nel processo della trans-traduzione. Sono stati condotti esperimenti sui mutanti per studiarne il fenotipo in diverse condizion...

  2. Cracking Streptococcus thermophilus to stimulate the growth of the probiotic Lactobacillus casei in co-culture.

    Science.gov (United States)

    Ma, Chengjie; Ma, Aimin; Gong, Guangyu; Liu, Zhenmin; Wu, Zhengjun; Guo, Benheng; Chen, Zhengjun

    2015-10-01

    Lactobacillus casei, a probiotic, and Streptococcus thermophilus, a fast acidifying lactic acid bacterial strain, are both used in the food industry. The aim of this study was to investigate the interaction between L. casei and S. thermophilus in the presence or absence of S. thermophilus-specific bacteriophage during milk fermentation. The acidification capability of L. casei co-cultured with S. thermophilus was significantly higher than that observed for L. casei or S. thermophilus cultured alone. However, the probiotic content (i.e., L. casei cell viability) was low. The fastest acidification and the highest viable L. casei cell count were observed in co-cultures of L. casei and S. thermophilus with S. thermophilus phage. In these co-cultures, S. thermophilus compensated for the slow acid production of L. casei in the early exponential growth phase. Thereafter, phage-induced lysis of the S. thermophilus cells eliminated the competition for nutrients, allowing L. casei to grow well. Additionally, the ruptured S. thermophilus cells released intracellular factors, which further promoted the growth and function of the probiotic bacteria. Crude cellular extract isolated from S. thermophilus also significantly accelerated the growth and propagation of L. casei, supporting the stimulatory role of the phage on this micro-ecosystem. PMID:26093989

  3. Genetic analysis of lipolytic activities in Thermus thermophilus HB27.

    Science.gov (United States)

    Leis, Benedikt; Angelov, Angel; Li, Haijuan; Liebl, Wolfgang

    2014-12-10

    The extremely thermophilic bacterium Thermus thermophilus HB27 displays lipolytic activity for the hydrolysis of triglycerides. In this study we performed a mutational in vivo analysis of esterases and lipases that confer growth on tributyrin. We interrupted 10 ORFs suspected to encode lipolytic enzymes. Two chromosomal loci were identified that resulted in reduced hydrolysis capabilities against tributyrin and various para-nitrophenyl acyl esters. By implementation of a convenient new one-step method which abstains from the use of selectable markers, a mutant strain with multiple scar-less deletions was constructed by sequentially deleting ORFs TT_C1787, TT_C0340, TT_C0341 and TT_C0904. The quadruple deletion mutant of T. thermophilus exhibited significantly lower lipolytic activity (approximately 25% residual activity compared to wild type strain) over a broad range of fatty acyl esters and had lost the ability to grow on agar plates containing tributyrin as the sole carbon source. Furthermore, we were able to determine the impact of each gene disruption on the lipolytic activity profile in this model organism and show that the esterase activity in T. thermophilus HB27 is due to a concerted action of several hydrolases having different substrate preferences and activities. The esterase-less T. thermophilus multi-deletion mutant from this study can be used as a screening and expression host for esterase genes from thermophiles or metagenomes. PMID:25102235

  4. Viability and cholesterol uptake by Streptococcus thermophilus cultures in artificial git fluids

    OpenAIRE

    Małgorzata Ziarno

    2010-01-01

    Background. Streptococcus thermophilus is traditionally used in association with Lb. delbrueckii subsp. bulgaricus as a starter culture for the production of yoghurt. Some researchers have indicated that S. thermophilus may provide additional health benefits, for example it may reduce cholesterol levels. The aim of this study was to in vitro evaluate the cholesterol uptake and the viability of S. thermophilus isolates in artificial GIT environments. Material and methods. Twelve isolates ...

  5. Production of probiotic fresh white cheese using co-culture with Streptococcus thermophilus

    OpenAIRE

    Oktay Yerlikaya; Elif Ozer

    2014-01-01

    In this research, the probiotic Streptococcus thermophilus was inoculated into milk as co-culture to produce probiotic cheese. The effects of using Streptococcus thermophilus with other probiotic bacteria on cheese composition, and microbiological viability during 28 days of storage were investigated. Sensorial properties were determined only at 1st and 28th days of storage. The results showed that the use of Streptococcus thermophilus as co-culture in probiotic cheese production did not affe...

  6. Bioprospecting of strains of Streptococcus thermophilus from Indian fermented milk products for folate production

    OpenAIRE

    Iyer, Ramya; Tomar, Sudhir Kumar; Mohanty, Ashok Kumar; Singh, Prashant; Singh, Rameshwar

    2011-01-01

    International audience This study deals with the bio-prospecting of folate producing strains of Streptococcus thermophilus isolated from milk and different fermented milk products of Indian origin. From a total of 500 randomly selected colonies isolated from 209 different samples, 117 isolates were identified as S. thermophilus by classical biochemical and molecular characterization. Frequency of incidence of S. thermophilus in the different samples of milk and milk products was variable w...

  7. Effects of Argonaute on Gene Expression in Thermus thermophilus

    OpenAIRE

    Swarts, D.C.; Koehorst, J.J.; Westra, E.R.; Schaap, P.J.; Oost, van der, J.

    2015-01-01

    BACKGROUND: Eukaryotic Argonaute proteins mediate RNA-guided RNA interference, allowing both regulation of host gene expression and defense against invading mobile genetic elements. Recently, it has become evident that prokaryotic Argonaute homologs mediate DNA-guided DNA interference, and play a role in host defense. Argonaute of the bacterium Thermus thermophilus (TtAgo) targets invading plasmid DNA during and after transformation. Using small interfering DNA guides, TtAgo can cleave single...

  8. Effects of Argonaute on Gene Expression in Thermus thermophilus

    OpenAIRE

    2015-01-01

    Background Eukaryotic Argonaute proteins mediate RNA-guided RNA interference, allowing both regulation of host gene expression and defense against invading mobile genetic elements. Recently, it has become evident that prokaryotic Argonaute homologs mediate DNA-guided DNA interference, and play a role in host defense. Argonaute of the bacterium Thermus thermophilus (TtAgo) targets invading plasmid DNA during and after transformation. Using small interfering DNA guides, TtAgo can cleave single ...

  9. Cloning, purification and crystallization of Thermus thermophilus proline dehydrogenase

    International Nuclear Information System (INIS)

    Cloning, purification and crystallization of T. thermophilus proline dehydrogenase is reported. The detergent n-octyl β-d-glucopyranoside was used to reduce polydispersity, which enabled crystallization. Nature recycles l-proline by converting it to l-glutamate. This four-electron oxidation process is catalyzed by the two enzymes: proline dehydrogenase (PRODH) and Δ1-pyrroline-5-carboxylate dehydrogenase. This note reports the cloning, purification and crystallization of Thermus thermophilus PRODH, which is the prototype of a newly discovered superfamily of bacterial monofunctional PRODHs. The results presented here include production of a monodisperse protein solution through use of the detergent n-octyl β-d-glucopyranoside and the growth of native crystals that diffracted to 2.3 Å resolution at Advanced Light Source beamline 4.2.2. The space group is P212121, with unit-cell parameters a = 82.2, b = 89.6, c = 94.3 Å. The asymmetric unit is predicted to contain two protein molecules and 46% solvent. Molecular-replacement trials using a fragment of the PRODH domain of the multifunctional Escherichia coli PutA protein as the search model (24% amino-acid sequence identity) did not produce a satisfactory solution. Therefore, the structure of T. thermophilus PRODH will be determined by multiwavelength anomalous dispersion phasing using a selenomethionyl derivative

  10. Unidirectional reconstitution into detergent-destabilized liposomes of the purified lactose transport system of Streptococcus thermophilus

    NARCIS (Netherlands)

    Veenhoff, Liesbeth; Liang, Wei-Jun; Henderson, Peter J.F.; Leblanc, Gérard; Poolman, Bert

    1996-01-01

    The lactose transport protein (LacS) of Streptococcus thermophilus was amplified to levels as high as 8 and 30% of total membrane protein in Escherichia coli and S, thermophilus, respectively, In both organisms the protein was functional and the expression levels were highest with the streptococcal

  11. Viability and cholesterol uptake by Streptococcus thermophilus cultures in artificial git fluids

    Directory of Open Access Journals (Sweden)

    Małgorzata Ziarno

    2010-03-01

    Full Text Available Background. Streptococcus thermophilus is traditionally used in association with Lb. delbrueckii subsp. bulgaricus as a starter culture for the production of yoghurt. Some researchers have indicated that S. thermophilus may provide additional health benefits, for example it may reduce cholesterol levels. The aim of this study was to in vitro evaluate the cholesterol uptake and the viability of S. thermophilus isolates in artificial GIT environments. Material and methods. Twelve isolates of S. thermophilus were cultured in artificial gastric fluid (with pepsin added and in artificial duodenal fluid (with the enzyme complex added, and in M17 broth containing cholesterol at an initial concentration of 600 µg/mL, as well as in M17 broth without cholesterol. Immediately after the adding of bacteria inoculums and at the end of experiment, the concentration of cholesterol and the number of bacteria were measured. Results. S. thermophilus did not remove statistically significant amounts of cholesterol from artificial gastric fluid. The isolates showed the ability to uptake cholesterol from M17 broth and artificial duodenal fluid, and the degree of cholesterol uptake depended on the isolate. All isolates of S. thermophilus remove much more cholesterol from M17 broth than from artificial duodenal fluid. All S. thermophilus isolates had worse survival in artificial gastric or duodenal fluids than in M17 broth. Conclusions. The ability of S. thermophilus cells to survive in artificial gastric fluid and artificial duodenal fluid varied according to the isolates.

  12. BlpC regulated bacteriocin production in Streptococcus thermophilus NRRL-B59671

    Science.gov (United States)

    Streptococcus thermophilus NRRL-B59671 was previously shown to produce a bacteriocin with anti-pediococcal activity, but the genetic components required for production were not characterized. Genome sequencing of several strains of S. thermophilus has identified a genetic locus which encodes a quor...

  13. Uptake of Branched-Chain Amino Acids by Streptococcus thermophilus

    OpenAIRE

    Akpemado, K. M.; Bracquart, P. A.

    1983-01-01

    The transport of branched-chain amino acids in Streptococcus thermophilus was energy dependent. The metabolic inhibitors of glycolysis and ATPase enzymes were active, but the proton-conducting uncouplers were not. Transport was optimal at temperatures of between 30 and 45°C and at pH 7.0 for the three amino acids leucine, valine, and isoleucine; a second peak existed at pH 5.0 with valine and isoleucine. By competition and kinetics studies, the branched-chain amino acids were found to share a...

  14. Preliminary X-ray crystallographic study of glucose dehydrogenase from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The glucose dehydrogenase (GDH) protein from T. thermophilus HB8 was cloned, expressed, purified and crystallized. GDH crystals belong to space group P21 and diffract to 1.9 Å resolution. Thermus thermophilus is an aerobic chemoorganotroph that has been found to grow anaerobically in the presence of nitrate. Crystals of glucose dehydrogenase (GDH) from T. thermophilus HB8 belong to space group P21, with unit-cell parameters a = 36.90, b = 132.96, c = 60.78 Å, β = 97.2°. Preliminary studies and molecular-replacement calculations reveal that the asymmetric unit contains two monomers

  15. Fast induction of nisin resistance in Streptococcus thermophilus INIA 463 during growth in milk.

    Science.gov (United States)

    Garde, Sonia; Avila, Marta; Medina, Margarita; Nuñez, Manuel

    2004-11-01

    Streptococcus thermophilus INIA 463 became nisin-resistant after exposure in skim milk to subminimal inhibitory concentrations of nisin (1-3 IU/ml) for less than 2 h. Addition of 20 IU/ml caused a 4 log unit decrease in S. thermophilus counts of a culture not exposed previously to nisin, whereas no decrease was observed in the culture exposed to nisin for 2 h. Transfer of immunity genes as responsible for nisin resistance was discarded. The presence of extracellular or intracellular specific nisin-degrading enzymes was not detected in the nisin-resistant variant of S. thermophilus INIA 463. Nisin resistance was caused by the induction of a resistance mechanism. Transmission electron microscopy (TEM) revealed that the nisin-resistant variant of S. thermophilus INIA 463 had a thickened cell wall compared to the wild strain. Resistance to nisin was lost after one transfer (4 h growth) in nisin-free skim milk. PMID:15364470

  16. Mechanism of resistance to macrolide-lincosamide-streptogramin antibiotics in Streptococcus thermophilus

    Science.gov (United States)

    Resistance to macrolide-lincosamide-streptogramin (MLS) group antibiotics in the dairy bacterium Streptococcus thermophilus (ST) is documented but the mechanism of resistance has not been elucidated. MIC values for erythromycin (Erm), azithromycin (Azm), tylosin (Tyl), spiramycin (Spm), pristinamyci...

  17. Cleavage of Phage DNA by the Streptococcus thermophilus CRISPR3-Cas System

    OpenAIRE

    Magadán, Alfonso H.; Marie-Ève Dupuis; Manuela Villion; Sylvain Moineau

    2012-01-01

    Streptococcus thermophilus, similar to other Bacteria and Archaea, has developed defense mechanisms to protect cells against invasion by foreign nucleic acids, such as virus infections and plasmid transformations. One defense system recently described in these organisms is the CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats loci coupled to CRISPR-associated genes). Two S. thermophilus CRISPR-Cas systems, CRISPR1-Cas and CRISPR3-Cas, have been shown to actively blo...

  18. Isolation and characterization of chromosomal promoters of Streptococcus salivarius subsp. thermophilus.

    Science.gov (United States)

    Slos, P; Bourquin, J C; Lemoine, Y; Mercenier, A

    1991-01-01

    A promoter probe vector, pTG244, was constructed with the aim of isolating transcription initiation signals from Streptococcus thermophilus (Streptococcus salivarius subsp. thermophilus). pTG244 is based on the Escherichia coli-streptococcus shuttle vector pTG222, into which the promoterless chloramphenicol acetyltransferase gene of Bacillus pumilus (cat-86) was cloned. Random Sau3A fragments from the S. thermophilus A054 chromosomal DNA were cloned upstream of the cat-86 gene by using E. coli as the host. The pool of recombinant plasmids were introduced into S. thermophilus and Lactococcus lactis subsp. lactis in order to search for promoter activity in these hosts. For S. thermophilus, it was necessary to first select erythromycin-resistant transformants and then to screen for chloramphenicol resistance among these. Direct selection of chloramphenicol-resistant clones was, however, possible in L. lactis subsp. lactis. Six fragments exhibiting promoter activity were characterized in S. thermophilus by measuring the levels of cat-86 transcription and/or chloramphenicol acetyltransferase specific activity. Three of the promoter-carrying fragments were sequenced. The 5' ends of their corresponding mRNAs were determined by S1 mapping and shown to correspond to a purine residue in all cases. Upstream from these potential transcription start points, sequences homologous to the E. coli sigma 70 and the Bacillus subtilis vegetative sigma 43 (or sigma A) consensus promoters were identified. Images PMID:1854195

  19. Effects of Argonaute on Gene Expression in Thermus thermophilus.

    Directory of Open Access Journals (Sweden)

    Daan C Swarts

    Full Text Available Eukaryotic Argonaute proteins mediate RNA-guided RNA interference, allowing both regulation of host gene expression and defense against invading mobile genetic elements. Recently, it has become evident that prokaryotic Argonaute homologs mediate DNA-guided DNA interference, and play a role in host defense. Argonaute of the bacterium Thermus thermophilus (TtAgo targets invading plasmid DNA during and after transformation. Using small interfering DNA guides, TtAgo can cleave single and double stranded DNAs. Although TtAgo additionally has been demonstrated to cleave RNA targets complementary to its DNA guide in vitro, RNA targeting by TtAgo has not been demonstrated in vivo.To investigate if TtAgo also has the potential to control RNA levels, we analyzed RNA-seq data derived from cultures of four T. thermophilus strain HB27 variants: wild type, TtAgo knockout (Δago, and either strain transformed with a plasmid. Additionally we determined the effect of TtAgo on expression of plasmid-encoded RNA and plasmid DNA levels.In the absence of exogenous DNA (plasmid, TtAgo presence or absence had no effect on gene expression levels. When plasmid DNA is present, TtAgo reduces plasmid DNA levels 4-fold, and a corresponding reduction of plasmid gene transcript levels was observed. We therefore conclude that TtAgo interferes with plasmid DNA, but not with plasmid-encoded RNA. Interestingly, TtAgo presence stimulates expression of specific endogenous genes, but only when exogenous plasmid DNA was present. Specifically, the presence of TtAgo directly or indirectly stimulates expression of CRISPR loci and associated genes, some of which are involved in CRISPR adaptation. This suggests that TtAgo-mediated interference with plasmid DNA stimulates CRISPR adaptation.

  20. Whole-Genome Sequences of Streptococcus thermophilus Strains TH1435 and TH1436, Isolated from Raw Goat Milk.

    Science.gov (United States)

    Treu, Laura; Vendramin, Veronica; Bovo, Barbara; Campanaro, Stefano; Corich, Viviana; Giacomini, Alessio

    2014-01-01

    We report the genome sequences of two Streptococcus thermophilus strains, TH1435 and TH1436, isolated from raw goat milk devoted to the production of artisanal cheese in the Friuli-Venezia Giulia region in Italy. The genome sequences of these two quickly acidifying strains are the first available genome sequences of S. thermophilus strains isolated in Italy. PMID:24435859

  1. INSERTION OF A HETEROLOGOUS GENE CONSTRUCT INTO A NON-FUNCTIONAL ORF OF THE STREPTOCOCCUS THERMOPHILUS CHROMOSOME

    Science.gov (United States)

    A vector was constructed to allow for the integration of recombinant genes within the chromosome of Streptococcus thermophilus. The vector, pINTRS, contained a temperature sensitive origin of replication and an erythromycin resistance gene for initial selection in S. thermophilus. The region of th...

  2. Multi-site-specific 16S rRNA methyltransferase RsmF from Thermus thermophilus

    DEFF Research Database (Denmark)

    Demirci, Hasan; Larsen, Line H G; Hansen, Trine;

    2010-01-01

    Cells devote a significant effort toward the production of multiple modified nucleotides in rRNAs, which fine tune the ribosome function. Here, we report that two methyltransferases, RsmB and RsmF, are responsible for all four 5-methylcytidine (m(5)C) modifications in 16S rRNA of Thermus...... thermophilus. Like Escherichia coli RsmB, T. thermophilus RsmB produces m(5)C967. In contrast to E. coli RsmF, which introduces a single m(5)C1407 modification, T. thermophilus RsmF modifies three positions, generating m(5)C1400 and m(5)C1404 in addition to m(5)C1407. These three residues are clustered near...

  3. Therapeutic effect of Streptococcus thermophilus CRL 1190-fermented milk on chronic gastritis

    Institute of Scientific and Technical Information of China (English)

    Cecilia; Rodríguez; Marta; Medici; Fernanda; Mozzi; Graciela; Font; de; Valdez

    2010-01-01

    AIM: To investigate the potential therapeutic effect of exopolysaccharide (EPS)-producing Streptococcus thermophilus (S. thermophilus) CRL 1190 fermented milk on chronic gastritis in Balb/c mice. METHODS: Balb/c mice were fed with the fermented milk for 7 d after inducing gastritis with acetyl-salicylic acid (ASA, 400 mg/kg body weight per day for 10 d). Omeprazole was included in this study as a positive therapeutic control. The gastric in? ammatory activity was evaluated from gastric histology and in? amm...

  4. Production of probiotic fresh white cheese using co-culture with Streptococcus thermophilus

    Directory of Open Access Journals (Sweden)

    Oktay Yerlikaya

    2014-09-01

    Full Text Available In this research, the probiotic Streptococcus thermophilus was inoculated into milk as co-culture to produce probiotic cheese. The effects of using Streptococcus thermophilus with other probiotic bacteria on cheese composition, and microbiological viability during 28 days of storage were investigated. Sensorial properties were determined only at 1st and 28th days of storage. The results showed that the use of Streptococcus thermophilus as co-culture in probiotic cheese production did not affect negatively the cheese components. Fat and dry matter properties of cheese weren't influenced by added probiotic bacteria. However, different level of pH, salt and lactic acid were detected. All probiotic bacteria were present in high levels throughout storage of cheeses, above 7 Log cfu.g- 1, threshold required for probiotic activity. Sensory panel showed that the highest average sensory evaluation points were recorded in cheeses made with Streptococcus thermophilus plus Lactobacillus casei, whereas other probiotic bacteria combinations had been affected less in regard to taste or appearance.

  5. Streptococcus thermophilus, an emerging and promising tool for heterologous expression: Advantages and future trends.

    Science.gov (United States)

    Lecomte, Xavier; Gagnaire, Valérie; Lortal, Sylvie; Dary, Annie; Genay, Magali

    2016-02-01

    Streptococcus thermophilus is the second most used bacterium in dairy industry. It is daily consumed by millions of people through the worldwide consumption of yogurts, cheeses and fermented milks. S. thermophilus presents many features that make it a good candidate for the production of heterologous proteins. First, its ability to be naturally transformable allows obtaining swiftly and easily recombinant strains using various genetic tools available. Second, its Generally Recognised As Safe status and its ability to produce beneficial molecules or to liberate bioactive peptides from milk proteins open up the way for the development of new functional foods to maintain health and well-being of consumers. Finally, its ability to survive the intestinal passage and to be metabolically active in gastrointestinal tract allows considering S. thermophilus as a potential tool for delivering various biological molecules to the gastrointestinal tract. The aim of this review is therefore to take stock of various genetic tools which can be employed in S. thermophilus to produce heterologous proteins and to highlight the advantages and future trends of use of this bacterium as a heterologous expression host. PMID:26611164

  6. Evaluating acetaldehyde synthesis from L-14C(U)] threonine by Streptococcus thermophilus and Lactobacillus bulgaricus

    International Nuclear Information System (INIS)

    To evaluate the synthesis of acetaldehyde from threonine during growth of yogurt cultures, Streptococcus thermophilus MS1 and Lactobacillus bulgaricus MR1 were grown in defined medium in which 10% of the total threonine was composed of L-[carbon-14(U)]threonine. Acetaldehyde production was monitored by formation of 2,4-dinitrophenylhydrazone followed by separation and analysis using high performance liquid chromatography. After growth for 8 h at 420C, approximately 2.0% of the total acetaldehyde (780.4 nmol) produced was from L-[carbon-14]threonine. Threonine aldolase activity was determined in cell-free extracts from S. thermophilus and L. bulgaricus grown in Elliker broth. Increasing incubation temperature from 30 to 420C decreased threonine aldolase activity in cells of the streptococcus harvested after 8 h of incubation. Effect of incubation temperature was more dramatic in cells harvested after 18 h where the activity of cells grown at 480C was 89% lower than that of cells grown at 300C. Cell extracts from S. thermophilus MS1 possessed higher threonine aldolase activity than did those from L. bulgaricus MR1. Increased assay temperature from 30 to 420C increased threonine aldolase activity in S. thermophilus MS1

  7. Characterization of DNA transport in the thermophilic bacterium Thermus thermophilus HB27.

    Science.gov (United States)

    Schwarzenlander, Cornelia; Averhoff, Beate

    2006-09-01

    Horizontal gene transfer has been a major force for genome plasticity over evolutionary history, and is largely responsible for fitness-enhancing traits, including antibiotic resistance and virulence factors. In particular, for adaptation of prokaryotes to extreme environments, lateral gene transfer seems to have played a crucial role. Recently, by performing a genome-wide mutagenesis approach with Thermus thermophilus HB27, we identified the first genes in a thermophilic bacterium for the uptake of free DNA, a process called natural transformation. Here, we present the first data on the biochemistry and bioenergetics of the DNA transport process in this thermophile. We report that linear and circular plasmid DNA are equally well taken up with a high maximal velocity of 1.5 microg DNA.(mg protein)(-1).min(-1), demonstrating an extremely efficient binding and uptake rate of 40 kb.s(-1).cell(-1). Uncouplers and ATPase inhibitors immediately inhibited DNA uptake, providing clear evidence that DNA translocation in HB27 is an energy-dependent process. DNA uptake studies with genomic DNA of Bacteria, Archaea and Eukarya revealed that Thermus thermophilus HB27 takes up DNA from members of all three domains of life. We propose that the extraordinary broad substrate specificity of the highly efficient Thermus thermophilus HB27 DNA uptake system may contribute significantly to thermoadaptation of Thermus thermophilus HB27 and to interdomain DNA transfer in hot environments. PMID:16939619

  8. Inhibition of microbial adhesion to silicone rubber treated with biosurfactant from Streptococcus thermophilus A

    NARCIS (Netherlands)

    Rodrigues, L; van der Mei, H; Banat, IM; Teixeira, J; Oliveira, R

    2006-01-01

    Microbial adhesion of four bacterial and two yeast strains isolated from explanted voice prostheses to silicone rubber before and after conditioning with a biosurfactant obtained from the probiotic bacterium Streptococcus thermophilus A was investigated in a parallel plate flow chamber. The silicone

  9. Purification, crystallization and preliminary X-ray diffraction study on pyrimidine nucleoside phosphorylase TTHA1771 from Thermus thermophilus HB8

    OpenAIRE

    Shimizu, Katsumi; Kunishima, Naoki

    2007-01-01

    The pyrimidine nucleoside phosphorylase TTHA1771 from T. thermophilus HB8 has been overexpressed, purified and crystallized. The crystals diffract X-rays to 1.8 Å resolution using synchrotron radiation.

  10. PEDIOCIN PRODUCTION IN MILK BY PEDIOCOCCUS ACIDILACTICI IN CO-CULTURE WITH STREPTOCOCCUS THERMOPHILUS AND LACTOBACILLUS DELBRUECKII SUBSP. BULGARICUS

    Science.gov (United States)

    The production of pediocin in milk by Pediococcus acidilactici was evaluated in co-culture with the dairy fermentation cultures Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Lactococcus lactis subsp. lactis. The cultures were tested singly or in different combinations...

  11. Enzymatic fractionation of the antimicrobial peptides casocidin and isracidin by Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus

    Science.gov (United States)

    The cumulative effect of peptidase and protease activities associated with cells of Streptococcus thermophilus (ST) and Lactobacillus delbrueckii subsp. bulgaricus (LB) was evaluated on the milk-protein based antimicrobial peptides casocidin and isracidin. Reaction mixtures of casocidin or isracidin...

  12. Crystallization and preliminary X-ray crystallographic analysis of Thermus thermophilus transcription elongation complex bound to Gfh1

    International Nuclear Information System (INIS)

    To elucidate which RNA polymerase structural state a particular T. thermophilus Gre-family protein (Gfh1) associates with, the T. thermophilus RNAP elongation complex was cocrystallized with Gfh1. RNA polymerase (RNAP) elongates RNA by iterative nucleotide-addition cycles (NAC). A specific structural state (or states) of RNAP may be the target of transcription elongation factors. Gfh1, a Thermus thermophilus Gre-family protein, inhibits NAC. To elucidate which RNAP structural state Gfh1 associates with, the T. thermophilus RNAP elongation complex (EC) was cocrystallized with Gfh1. Of the 70 DNA/RNA scaffolds tested, two (for EC1 and EC2) were successfully crystallized. In the presence of Gfh1, EC1 and EC2 yielded crystals belonging to space group P21 with similar unit-cell parameters (crystals 1 and 2, respectively). X-ray diffraction data sets were obtained at 3.6 and 3.8 Å resolution, respectively

  13. Cloning, nucleotide sequence, and engineered expression of Thermus thermophilus DNA ligase, a homolog of Escherichia coli DNA ligase.

    OpenAIRE

    Lauer, G; Rudd, E A; McKay, D L; Ally, A; Ally, D; Backman, K C

    1991-01-01

    We have cloned and sequenced the gene for DNA ligase from Thermus thermophilus. A comparison of this sequence and those of other ligases reveals significant homology only with that of Escherichia coli. The overall amino acid composition of the thermophilic ligase and the pattern of amino acid substitutions between the two proteins are consistent with compositional biases in other thermophilic enzymes. We have engineered the expression of the T. thermophilus gene in Escherichia coli, and we sh...

  14. Carbohydrate metabolism is essential for the colonization of Streptococcus thermophilus in the digestive tract of gnotobiotic rats.

    Directory of Open Access Journals (Sweden)

    Muriel Thomas

    Full Text Available Streptococcus thermophilus is the archetype of lactose-adapted bacterium and so far, its sugar metabolism has been mainly investigated in vitro. The objective of this work was to study the impact of lactose and lactose permease on S. thermophilus physiology in the gastrointestinal tract (GIT of gnotobiotic rats. We used rats mono-associated with LMD-9 strain and receiving 4.5% lactose. This model allowed the analysis of colonization curves of LMD-9, its metabolic profile, its production of lactate and its interaction with the colon epithelium. Lactose induced a rapid and high level of S. thermophilus in the GIT, where its activity led to 49 mM of intra-luminal L-lactate that was related to the induction of mono-carboxylic transporter mRNAs (SLC16A1 and SLC5A8 and p27(Kip1 cell cycle arrest protein in epithelial cells. In the presence of a continuous lactose supply, S. thermophilus recruited proteins involved in glycolysis and induced the metabolism of alternative sugars as sucrose, galactose, and glycogen. Moreover, inactivation of the lactose transporter, LacS, delayed S. thermophilus colonization. Our results show i/that lactose constitutes a limiting factor for colonization of S. thermophilus, ii/that activation of enzymes involved in carbohydrate metabolism constitutes the metabolic signature of S. thermophilus in the GIT, iii/that the production of lactate settles the dialogue with colon epithelium. We propose a metabolic model of management of carbohydrate resources by S. thermophilus in the GIT. Our results are in accord with the rationale that nutritional allegation via consumption of yogurt alleviates the symptoms of lactose intolerance.

  15. Sequencing and transcriptional analysis of the streptococcus thermophilus histamine biosynthesis gene cluster: Factors that affect differential hdca expression

    OpenAIRE

    Calles-Enríquez, Marina; Hjort Eriksen, Benjamin; Skov Andersen, Pia; Rattray, F.; Johansen, Annette H.; Fernández García, María; Ladero Losada, Víctor Manuel; Álvarez González, Miguel Ángel

    2010-01-01

    Histamine, a toxic compound that is formed by the decarboxylation of histidine through the action of microbial decarboxylases, can accumulate in fermented food products. From a total of 69 Streptococcus thermophilus strains screened, two strains, CHCC1524 and CHCC6483, showed the capacity to produce histamine. The hdc clusters of S. thermophilus CHCC1524 and CHCC6483 were sequenced, and the factors that affect histamine biosynthesis and histidine-decarboxylating gene (hdcA) expression were st...

  16. Preparation of low galactose yogurt using cultures of Gal+Streptococcus thermophilus in combination with Lactobacillus delbrueckii ssp. bulgaricus

    OpenAIRE

    Anbukkarasi, Kaliyaperumal; UmaMaheswari, Thiyagamoorthy; Hemalatha, Thiagarajan; Nanda, Dhiraj Kumar; Singh, Prashant; Singh, Rameshwar

    2014-01-01

    Streptococcus thermophilus is an important lactic starter used in the production of yogurt. Most strains of S. thermophilus are galactose negative (Gal−) and are able to metabolize only glucose portion of lactose and expel galactose into the medium. This metabolic defect leads to the accumulation of free galactose in yogurt, resulting in galactosemia among consumers. Hence there is an absolute need to develop low galactose yogurt. Therefore, in this study, three galactose positive (Gal+) S. t...

  17. The ltp gene of temperate Streptococcus thermophilus phage TP-J34 confers superinfection exclusion to Streptococcus thermophilus and Lactococcus lactis

    International Nuclear Information System (INIS)

    The ltp gene, located within the lysogeny module of temperate Streptococcus thermophilus phage TP-J34, has been shown to be expressed in lysogenic strain S. thermophilus J34. It codes for a lipoprotein, as demonstrated by inhibition of cleavage of the signal sequence by globomycin. Exposure of Ltp on the surface of Lactococcus lactis protoplasts bearing a plasmid-encoded copy of ltp has been demonstrated by immunogold labeling and electron microscopy. Expression of ltp in prophage- and plasmid-cured S. thermophilus J34-6f interfered with TP-J34 infection. While plating efficiency was reduced by a factor of about 40 and lysis of strain J34-6f in liquid medium was delayed considerably, phage adsorption was not affected at all. Intracellular accumulation of phage DNA was shown to be inhibited by Ltp. This indicates interference of Ltp with infection at the stage of triggering DNA release and injection into the cell, indicating a role of Ltp in superinfection exclusion. Expression of ltp in L. lactis Bu2-60 showed that the same superinfection exclusion mechanism was strongly effective against phage P008, a member of the lactococcal 936 phage species: no plaque-formation was detectable with even 109 phage per ml applied, and lysis in liquid medium did not occur. In Lactococcus also, Ltp apparently inhibited phage DNA release and/or injection. Ltp appears to be a member of a family of small, secreted proteins with a 42 amino acids repeat structure encoded by genes of Gram-positive bacteria. Some of these homologous genes are part of the genomes of prophages

  18. Standardization of lyophilization medium for Streptococcus thermophilus subjected to viability escalation on freeze drying

    Directory of Open Access Journals (Sweden)

    Rohit Sharma

    2014-09-01

    Full Text Available The objective of the present study is to develop a lyophilization medium for Streptococcus thermophilus (NCIM 2904 as the industrial exploitation of this bacterium totally depends upon preservation and lyophilization protocols. Protective effect of 18 compounds were observed individually and in combinations with different sugars, sugar alcohols, polymers, protein concentrates and buffers. Among all the protectants tested, ammonium citrate (1% w/w, K2HPO4 (1% w/w and KH2PO4 (1% w/w provided lowest protection to these bacterial cells while 10% (w/w sodium caseinate, whey protein concentrate, sweet whey powder, and skim milk showed significant results in viability escalation. Survival in carbon sources like lactose, sucrose and maltodextrine was also favored maximally. Combination of sodium caseinate 10%, skim milk 5%, sucrose 5%, lactose 5% and mono sodium glutamate 1% in distilled water in ratio of 1:5 with S. thermophilus showed survival percentage of 96%.

  19. Physicochemical characteristics and bioactivities of the exopolysaccharide and its sulphated polymer from Streptococcus thermophilus GST-6.

    Science.gov (United States)

    Zhang, Jian; Cao, Yongqiang; Wang, Ji; Guo, Xialei; Zheng, Yi; Zhao, Wen; Mei, Xueyang; Guo, Ting; Yang, Zhennai

    2016-08-01

    Exopolysaccharide (EPS) produced by Streptococcus thermophilus GST-6 in skim milk was extracted and purified. The EPS was composed of glucose and galactose in a molar ratio of 1.80:1.03 with identical primary structure to the EPS from S. thermophilus ST1 reported previously. The purified EPS was sulphated at a sulphonation degree of 0.26±0.03, and presence of sulphate groups in the sulphated EPS (SEPS) was confirmed. Microstructural studies demonstrated a porous web with coarse surface for the EPS while the SEPS appeared as stacked flakes with relatively uniform shapes. Sulphonation of the EPS slightly decreased its degrading temperature from 234.6°C to 232.5°C. The DPPH, superoxide and hydroxyl radicals scavenging activities of the EPS were significantly (P<0.05) improved after sulphonation. The SEPS also showed stronger inhibitory activity than the EPS against Eschericia coli, Salmonella typhimurium and Staphylococcus aureus. PMID:27112886

  20. Effect of freeze drying process on some properties of Streptococcus thermophilus isolated from dairy products

    OpenAIRE

    Selwal, Krishan K.; Selwal, Manjit K.; D.N. Gandhi

    2011-01-01

    The present investigation represents the effect of freeze drying on some properties as acid and bile tolerance of Streptococcus thermophilus MTCC 1938 culture isolated from dairy products. The cell paste obtained from milk based medium was freeze dried with a pressure of 50-100 mtorr for 24h at -40ºC. Acid and bile tolerance test exhibited 3.8-4.9 and 3.2-3.8 log counts reduction after freeze drying respectively.

  1. Effect of freeze drying process on some properties of Streptococcus thermophilus isolated from dairy products

    OpenAIRE

    Selwal, Krishan K.; Selwal, Manjit K.; D.N. Gandhi

    2011-01-01

    The present investigation represents the effect of freeze drying on some properties as acid and bile tolerance of Streptococcus thermophilus MTCC 1938 culture isolated from dairy products. The cell paste obtained from milk based medium was freeze dried with a pressure of 50–100 mtorr for 24h at -40°C. Acid and bile tolerance test exhibited 3.8–4.9 and 3.2–3.8 log counts reduction after freeze drying respectively.

  2. Standardization of lyophilization medium for Streptococcus thermophilus subjected to viability escalation on freeze drying

    OpenAIRE

    Rohit Sharma; Bhagwan S. Sanodiya; Gulab S. Thakur; Pallavi Jaiswal; Anjana Sharma; Bisen, Prakash S.

    2014-01-01

    The objective of the present study is to develop a lyophilization medium for Streptococcus thermophilus (NCIM 2904) as the industrial exploitation of this bacterium totally depends upon preservation and lyophilization protocols. Protective effect of 18 compounds were observed individually and in combinations with different sugars, sugar alcohols, polymers, protein concentrates and buffers. Among all the protectants tested, ammonium citrate (1% w/w), K2HPO4 (1% w/w) and KH2PO4 (1% w/w) provide...

  3. Isolation and partial characterization of a biosurfactant produced by streptococcus thermophilus A

    OpenAIRE

    Rodrigues, L. R.; Teixeira, J.A.; Mei, Henny van der; Oliveira, Rosário

    2006-01-01

    Isolation and characterization of the surface active components from the crude biosurfactant produced by Streptococcus thermophilus A was studied. A fraction rich in glycolipids was obtained by the fractionation of crude biosurfactant using hydrophobic interaction chromatography. Molecular (by Fourier transform infrared spectroscopy) and elemental compositions (by X-ray photoelectron spectroscopy) were determined. Critical micelle concentration achieved was 20 g/l, allowing for a surfac...

  4. Bioremediation potential of a newly isolate solvent tolerant strain Bacillus thermophilus PS11

    OpenAIRE

    PAYEL SARKAR; SHILPI GHOSH

    2012-01-01

    The increased generation of solvent waste has been stated as one of the most critical environmental problems. Though microbial bioremediation has been widely used for waste treatment but their application in solvent waste treatment is limited since the solvents have toxic effects on the microbial cells. A solvent tolerant strain of Bacillus thermophilus PS11 was isolated from soil by cyclohexane enrichment. Transmission electron micrograph of PS11 showed convoluted cell membrane and accumulat...

  5. Genetically Engineered Immunomodulatory Streptococcus thermophilus Strains Producing Antioxidant Enzymes Exhibit Enhanced Anti-Inflammatory Activities

    OpenAIRE

    del Carmen, Silvina; de Moreno de LeBlanc, Alejandra; Martin, Rebeca; Chain, Florian; Langella, Philippe; Bermúdez-Humarán, Luis G; LeBlanc, Jean Guy

    2014-01-01

    The aims of this study were to develop strains of lactic acid bacteria (LAB) having both immunomodulatory and antioxidant properties and to evaluate their anti-inflammatory effects both in vitro, in different cellular models, and in vivo, in a mouse model of colitis. Different Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were cocultured with primary cultures of mononuclear cells. Analysis of the pro- and anti-inflammatory cytokines secreted by these cells...

  6. Genetically engineered immunomodulatory Streptococcus thermophilus strains producing antioxidant enzymes exhibit enhanced anti-inflammatory activities.

    Science.gov (United States)

    Del Carmen, Silvina; de Moreno de LeBlanc, Alejandra; Martin, Rebeca; Chain, Florian; Langella, Philippe; Bermúdez-Humarán, Luis G; LeBlanc, Jean Guy

    2014-02-01

    The aims of this study were to develop strains of lactic acid bacteria (LAB) having both immunomodulatory and antioxidant properties and to evaluate their anti-inflammatory effects both in vitro, in different cellular models, and in vivo, in a mouse model of colitis. Different Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were cocultured with primary cultures of mononuclear cells. Analysis of the pro- and anti-inflammatory cytokines secreted by these cells after coincubation with candidate bacteria revealed that L. delbrueckii subsp. bulgaricus CRL 864 and S. thermophilus CRL 807 display the highest anti-inflammatory profiles in vitro. Moreover, these results were confirmed in vivo by the determination of the cytokine profiles in large intestine samples of mice fed with these strains. S. thermophilus CRL 807 was then transformed with two different plasmids harboring the genes encoding catalase (CAT) or superoxide dismutase (SOD) antioxidant enzymes, and the anti-inflammatory effects of recombinant streptococci were evaluated in a mouse model of colitis induced by trinitrobenzenesulfonic acid (TNBS). Our results showed a decrease in weight loss, lower liver microbial translocation, lower macroscopic and microscopic damage scores, and modulation of the cytokine production in the large intestines of mice treated with either CAT- or SOD-producing streptococci compared to those in mice treated with the wild-type strain or control mice without any treatment. Furthermore, the greatest anti-inflammatory activity was observed in mice receiving a mixture of both CAT- and SOD-producing streptococci. The addition of L. delbrueckii subsp. bulgaricus CRL 864 to this mixture did not improve their beneficial effects. These findings show that genetically engineering a candidate bacterium (e.g., S. thermophilus CRL 807) with intrinsic immunomodulatory properties by introducing a gene expressing an antioxidant enzyme enhances its anti

  7. The Streptococcus thermophilus CRISPR/Cas system provides immunity in Escherichia coli

    OpenAIRE

    Sapranauskas, Rimantas; Gasiunas, Giedrius; Fremaux, Christophe; Barrangou, Rodolphe; Horvath, Philippe; Siksnys, Virginijus

    2011-01-01

    The CRISPR/Cas adaptive immune system provides resistance against phages and plasmids in Archaea and Bacteria. CRISPR loci integrate short DNA sequences from invading genetic elements that provide small RNA-mediated interference in subsequent exposure to matching nucleic acids. In Streptococcus thermophilus, it was previously shown that the CRISPR1/Cas system can provide adaptive immunity against phages and plasmids by integrating novel spacers following exposure to these foreign genetic elem...

  8. Confounders of mutation-rate estimators: selection and phenotypic lag in Thermus thermophilus

    OpenAIRE

    Kissling, Grace E.; Grogan, Dennis W.; John W Drake

    2013-01-01

    In a recent description of the rate and character of spontaneous mutation in the hyperthermophilic bacterium Thermus thermophilus, the mutation rate was observed to be substantially lower than seen in several mesophiles. Subsequently, a report appeared indicating that this bacterium maintains an average of about 4.5 genomes per cell. This number of genomes might result in a segregation lag for the expression of a recessive mutation and might therefore lead to an underestimate of the rate of m...

  9. In vitro reconstitution of Cascade-mediated CRISPR immunity in Streptococcus thermophilus

    OpenAIRE

    Sinkunas, Tomas; Gasiunas, Giedrius; Waghmare, Sakharam P; Dickman, Mark J; Barrangou, Rodolphe; Horvath, Philippe; Siksnys, Virginijus

    2013-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR)-encoded immunity in Type I systems relies on the Cascade (CRISPR-associated complex for antiviral defence) ribonucleoprotein complex, which triggers foreign DNA degradation by an accessory Cas3 protein. To establish the mechanism for adaptive immunity provided by the Streptococcus thermophilus CRISPR4-Cas (CRISPR-associated) system (St-CRISPR4-Cas), we isolated an effector complex (St-Cascade) containing 61-nucleotide CRISPR R...

  10. Cleavage of phage DNA by the Streptococcus thermophilus CRISPR3-Cas system.

    Directory of Open Access Journals (Sweden)

    Alfonso H Magadán

    Full Text Available Streptococcus thermophilus, similar to other Bacteria and Archaea, has developed defense mechanisms to protect cells against invasion by foreign nucleic acids, such as virus infections and plasmid transformations. One defense system recently described in these organisms is the CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats loci coupled to CRISPR-associated genes. Two S. thermophilus CRISPR-Cas systems, CRISPR1-Cas and CRISPR3-Cas, have been shown to actively block phage infection. The CRISPR1-Cas system interferes by cleaving foreign dsDNA entering the cell in a length-specific and orientation-dependant manner. Here, we show that the S. thermophilus CRISPR3-Cas system acts by cleaving phage dsDNA genomes at the same specific position inside the targeted protospacer as observed with the CRISPR1-Cas system. Only one cleavage site was observed in all tested strains. Moreover, we observed that the CRISPR1-Cas and CRISPR3-Cas systems are compatible and, when both systems are present within the same cell, provide increased resistance against phage infection by both cleaving the invading dsDNA. We also determined that overall phage resistance efficiency is correlated to the total number of newly acquired spacers in both CRISPR loci.

  11. Crystallization and preliminary crystallographic analysis of molybdenum-cofactor biosynthesis protein C from Thermus thermophilus

    International Nuclear Information System (INIS)

    The molybdenum-cofactor biosynthesis protein C from T. thermophilus has been crystallized in two different space groups, P21 and R32; the crystals diffracted to 1.9 and 1.75 Å resolution, respectively. The Gram-negative aerobic eubacterium Thermus thermophilus is an extremely important thermophilic microorganism that was originally isolated from a thermal vent environment in Japan. The molybdenum cofactor in this organism is considered to be an essential component required by enzymes that catalyze diverse key reactions in the global metabolism of carbon, nitrogen and sulfur. The molybdenum-cofactor biosynthesis protein C derived from T. thermophilus was crystallized in two different space groups. Crystals obtained using the first crystallization condition belong to the monoclinic space group P21, with unit-cell parameters a = 64.81, b = 109.84, c = 115.19 Å, β = 104.9°; the crystal diffracted to a resolution of 1.9 Å. The other crystal form belonged to space group R32, with unit-cell parameters a = b = 106.57, c = 59.25 Å, and diffracted to 1.75 Å resolution. Preliminary calculations reveal that the asymmetric unit contains 12 monomers and one monomer for the crystals belonging to space group P21 and R32, respectively

  12. Preparation of low galactose yogurt using cultures of Gal(+) Streptococcus thermophilus in combination with Lactobacillus delbrueckii ssp. bulgaricus.

    Science.gov (United States)

    Anbukkarasi, Kaliyaperumal; UmaMaheswari, Thiyagamoorthy; Hemalatha, Thiagarajan; Nanda, Dhiraj Kumar; Singh, Prashant; Singh, Rameshwar

    2014-09-01

    Streptococcus thermophilus is an important lactic starter used in the production of yogurt. Most strains of S. thermophilus are galactose negative (Gal(-)) and are able to metabolize only glucose portion of lactose and expel galactose into the medium. This metabolic defect leads to the accumulation of free galactose in yogurt, resulting in galactosemia among consumers. Hence there is an absolute need to develop low galactose yogurt. Therefore, in this study, three galactose positive (Gal(+)) S. thermophilus strains from National Collection of Dairy Cultures (NCDC) viz. NCDC 659 (AJM), NCDC 660 (JM1), NCDC 661 (KM3) and a reference galactose negative (Gal(-)) S. thermophilus NCDC 218 were used for preparation of low galactose yogurt. In milk fermented using S. thermophilus isolates alone, NCDC 659 released less galactose (0.27 %) followed by NCDC 661 (0.3 %) and NCDC 660 (0.45 %) after 10 h at 42 °C. Milk was fermented in combination with Gal(-) L. delbrueckii subsp. bulgaricus NCDC 04, in which NCDC 659 released least galactose upto 0.49 % followed by NCDC 661 (0.51 %) and NCDC 660 (0.60 %) than reference Gal(-) NCDC 218(0.79 %). Low galactose yogurt was prepared following standard procedure using Gal(+) S. thermophilus isolates and Gal(-) L. delbrueckii subsp. bulgaricus NCDC 04 in 1:1 ratio. Among which low galactose yogurt by NCDC 659 combination contained less galactose 0.37 % followed by NCDC 661 (0.51 %), NCDC 660 (0.65 %) and reference Gal(-) NCDC 218 (0.98 %) after 4 h of fermentation. This study clearly reveals that Gal(+) S. thermophilus isolates can be paired with Gal(-) L. delbrueckii subsp. bulgaricus for developing low galactose yogurt. PMID:25190881

  13. Therapeutic effect of Streptococcus thermophilus CRL 1190-fermented milk on chronic gastritis

    Directory of Open Access Journals (Sweden)

    Cecilia Rodríguez, Marta Medici, Fernanda Mozzi, Graciela Font de Valdez

    2010-04-01

    Full Text Available AIM: To investigate the potential therapeutic effect of exopolysaccharide (EPS-producing Streptococcus thermophilus (S. thermophilus CRL 1190 fermented milk on chronic gastritis in Balb/c mice.METHODS: Balb/c mice were fed with the fermented milk for 7 d after inducing gastritis with acetyl-salicylic acid (ASA, 400 mg/kg body weight per day for 10 d. Omeprazole was included in this study as a positive therapeutic control. The gastric inflammatory activity was evaluated from gastric histology and inflammation score, number of interleukin-10 (IL-10, interferon-γ (INFγ and tumor necrosis factor-α (TNF-α cytokine-producing cells in the gastric mucosa, and thickness of the mucus layer.RESULTS: Animals receiving treatment with the EPS-producing S. thermophilus CRL 1190 fermented milk showed a conserved gastric mucosa structure similar to that of healthy animals. Inflammation scores of the fermented milk-treated mice were lower than those of mice in the gastritis group (0.2 ± 0.03 vs 2.0 ± 0.6, P < 0.05. A marked decrease in INFγ+ (15 ± 1.0 vs 28 ± 1.2, P < 0.05 and TNF-α+ (16 ± 3.0 vs 33 ± 3.0, P < 0.05 cells and an increase in IL-10+ (28 ± 1.5 vs 14 ± 1.3, P < 0.05 cells compared to the gastritis group, was observed. Also, an increase in the thickness of the mucus gel layer (2.2 ± 0.6 vs 1.0 ± 0.3; 5.1 ± 0.8 vs 1.5 ± 0.4 in the corpus and antrum mucosa, respectively, P < 0.05 compared with the gastritis group was noted. A milk suspension of the purified EPS from S. thermophilus CRL1190 was also effective as therapy for gastritis.CONCLUSION: This study suggests that fermented milk with S. thermophilus CRL 1190 and/or its EPS could be used in novel functional foods as an alternative natural therapy for chronic gastritis induced by ASA.

  14. Cloning, expression and purification of D-Tyr-tRNATyr-deacylase from Thermus thermophilus

    Directory of Open Access Journals (Sweden)

    Rybak M. Yu.

    2015-06-01

    Full Text Available D-Tyr-tRNATyr-deacylase (DTD is a conservative enzyme, found in all domains of life, which ensures an additional checkpoint in the recycling of misaminoacylated D-Tyr-tRNATyr. DTD is capable of accelerating the hydrolysis of the ester linkage of D-Tyr-tRNATyr producing a free tRNA and D-tyrosine, thereby preventing an incorrect incorporation of D-amino acids into proteins. Deacylase distinguishes between D- and L-aminoacyl moieties and does not hydrolyze L-aminoacylated tRNA. The structural bases of this specificity and the mechanism of D-aminoacyl-tRNA hydrolysis are poorly understood. Aim. To clone D-Tyr-tRNATyr-deacylase from T. thermophilus (DTDTT, optimize the conditions for its expression in E.coli and develop an efficient purification procedure yielding the high quality enzyme suitable for the structural and functional studies. Methods. For amplification of DTD gene from T. thermophilus genomic DNA and its cloning into the pProEXHTb expression vector modern techniques were applied. Purification of the recombinant DTD protein was done with three types of column chromatography. His-tag was cleaved out from DTD by TEV protease. The cleavage was confirmed by Western blot analysis with anti-His-tag antibodies. Molecular weight of purified DTDTT was determined by the gel-filtration. Results. The expression construct pProEXHTb, containing DTD sequence from T. thermophilus, was obtained and successfully expressed in the BL21(DE3pLysS E.coli strain. The protein of interest was purified to homogeneity by the combination of affinity (Ni-NTA, anion-exchange (Q-Sepharose and size-exclusion (Superdex S 200 chromatographies. 2 mg of more than 90% pure recombinant DTD can be obtained from 1 L of bacterial culture. Molecular weight of purified DTD from T. thermophilus was determined to be 32 kDa, suggesting its dimeric structure. Conclusions. The pProEXHTb expression vector can be used for expression of DTD from T. thermophilus. The preparative amounts of

  15. Nutritional Composition and Protein Profile of Goat Yogurt PE with Double Culture between Streptococcus thermophilus and Lactobacilus species

    OpenAIRE

    Budiarti, Ismi Kurnia; Padaga, Masdiana C.; Fatchiyah, Fatchiyah

    2013-01-01

    Aim: The aims of this study are to characterize the nutrient compositions and protein profiles of Etawah breed (PE) goat yogurt fermented by double cultures . Material and Methods: To accomplish this, we used goat and bovine milk in five treatment groups: (1) fresh milk bovine, (2) goat,(3) milk fermented by L. acidophilus and S. thermophilus (LA + ST), (4) L. bulgaricus and S. thermophilus (LB+ ST),and (5) a comersial mixture. PE goat milk was fermented using 2.5% starting bacterial con...

  16. Nutritional Composition and Protein Profile of Goat Yogurt PE with Double Culture between Streptococcus thermophilus and Lactobacilus species

    OpenAIRE

    Ismi Kurnia Budiarti; Padaga, Masdiana C.; Fatchiyah Fatchiyah

    2013-01-01

    Aim: The aims of this study are to characterize the nutrient compositions and protein profiles of Etawah breed (PE) goat yogurt fermented by double cultures . Material and Methods: To accomplish this, we used goat and bovine milk in five treatment groups: (1) fresh milk bovine, (2) goat,(3) milk fermented by L. acidophilus and S. thermophilus (LA + ST), (4) L. bulgaricus and S. thermophilus (LB+ ST),and (5) a comersial mixture. PE goat milk was fermented using 2.5% starting bacterial concentr...

  17. Structure and mechanism of the aberrant ba3-cytochrome c oxidase from Thermus thermophilus

    OpenAIRE

    Soulimane, Tewfik; Buse, Gerhard; Bourenkov, Gleb P.; Bartunik, Hans D.; Huber, Robert; Than, Manuel E

    2000-01-01

    Cytochrome c oxidase is a respiratory enzyme catalysing the energy-conserving reduction of molecular oxygen to water. The crystal structure of the ba3-cytochrome c oxidase from Thermus thermophilus has been determined to 2.4 Å resolution using multiple anomalous dispersion (MAD) phasing and led to the discovery of a novel subunit IIa. A structure-based sequence alignment of this phylogenetically very distant oxidase with the other structurally known cytochrome oxidases leads to the identifica...

  18. Phosphorylation and Functional Properties of the IIA Domain of the Lactose Transport Protein of Streptococcus thermophilus

    OpenAIRE

    Gunnewijk, M.G W; Postma, P W; Poolman, B

    1999-01-01

    The lactose-H+ symport protein (LacS) of Streptococcus thermophilus has a carboxyl-terminal regulatory domain (IIALacS) that is homologous to a family of proteins and protein domains of the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS) in various organisms, of which IIAGlc of Escherichia coli is the best-characterized member. On the basis of these similarities, it was anticipated that IIALacS would be able to perform one or more functions associated with IIAGlc, i.e., carr...

  19. Characterization of the PIB-Type ATPases Present in Thermus thermophilus

    OpenAIRE

    Schurig-Briccio, Lici A.; Gennis, Robert B.

    2012-01-01

    PIB-type ATPases transport heavy metals (Cu2+, Cu+, Ag+, Zn2+, Cd2+, Co2+) across biomembranes, playing a key role in homeostasis and in the mechanisms of biotolerance of these metals. Three genes coding for putative PIB-type ATPases are present in the genome of Thermus thermophilus (HB8 and HB27): the TTC1358, TTC1371, and TTC0354 genes; these genes are annotated, respectively, as two copper transporter (CopA and CopB) genes and a zinc-cadmium transporter (Zn2+/Cd2+-ATPase) gene. We cloned a...

  20. Genomic restriction map of the extremely thermophilic bacterium Thermus thermophilus HB8.

    OpenAIRE

    Borges, K M; Bergquist, P L

    1993-01-01

    A physical map of the chromosome of the extremely thermophilic eubacterium Thermus thermophilus HB8 has been constructed by using pulsed-field gel electrophoresis techniques. A total of 26 cleavage sites for the rarely cutting restriction endonucleases HpaI, MunI, and NdeI were located on the genome. On the basis of the sizes of the restriction fragments generated, the genome size was estimated to be 1.74 Mbp, which is significantly smaller than the chromosomes of Escherichia coli and other m...

  1. Purification, Characterization, Gene Cloning, Sequencing, and Overexpression of Aminopeptidase N from Streptococcus thermophilus A

    OpenAIRE

    Chavagnat, Frederic; Casey, Michael G.; Meyer, Jacques

    1999-01-01

    The general aminopeptidase PepN from Streptococcus thermophilus A was purified to protein homogeneity by hydroxyapatite, anion-exchange, and gel filtration chromatographies. The PepN enzyme was estimated to be a monomer of 95 kDa, with maximal activity on N-Lys–7-amino-4-methylcoumarin at pH 7 and 37°C. It was strongly inhibited by metal chelating agents, suggesting that it is a metallopeptidase. The activity was greatly restored by the bivalent cations Co2+, Zn2+, and Mn2+. Except for prolin...

  2. Lactose uptake driven by galactose efflux in Streptococcus thermophilus: Evidence for a galactose-lactose antiporter

    International Nuclear Information System (INIS)

    Galactose-nonfermenting (Gal-) Streptococcus thermophilus TS2 releases galactose into the extracellular medium when grown in medium containing excess lactose. Starved and de-energized Gal- cells, however, could be loaded with galactose to levels approximately equal to the extracellular concentration (0 to 50 mM). When loaded cells were separated from the medium and resuspended in fresh broth containing 5 mM lactose, galactose efflux occurred. De-energized, galactose-loaded cells, resuspended in buffer or medium, accumulated [14C]lactose at a greater rate and to significantly higher intracellular concentrations than unloaded cells. Uptake of lactose by loaded cells was inhibited more than that by unloaded cells in the presence of extracellular galactose, indicating that a galactose gradient was involved in the exchange system. When de-energized, galactose-loaded cells were resuspended in carbohydrate-free medium at pH 6.7, a proton motive force (Δp) of 86 to 90 mV was formed, whereas de-energized, nonloaded cells maintained a Δp of about 56 mV. However, uptake of lactose by loaded cells occurred when the proton motive force was abolished by the addition of an uncoupler or in the presence of a proton-translocating ATPase inhibitor. These results support the hypothesis that galactose efflux in Gal- S. thermophilus is electrogenic and that the exchange reaction (lactose uptake and galactose efflux) probably occurs via an antiporter system

  3. Structure of a UPF0150-family protein from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The crystal structure of the hypothetical protein TTHA0281 from T. thermophilus HB8 has been determined at 1.9 Å resolution. The TTHA0281 protein forms a homotetramer in which each monomer adopts an α-β-β-β-α fold. TTHA0281 is a hypothetical protein from Thermus thermophilus HB8 that belongs to an uncharacterized protein family, UPF0150, in the Pfam database and to COG1598 in the National Center for Biotechnology Information Database of Clusters of Orthologous Groups. The X-ray crystal structure of the protein was determined by a multiple-wavelength anomalous dispersion technique and was refined at 1.9 Å resolution to a final R factor of 18.5%. The TTHA0281 monomer adopts an α-β-β-β-α fold and forms a homotetramer. Based on the properties and functions of structural homologues of the TTHA0281 monomer, the TTHA0281 protein is speculated to be involved in RNA metabolism, including RNA binding and cleavage

  4. Structure of the stand-alone RAM-domain protein from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The crystal structure of the stand-alone RAM domain from T. thermophilus HB8 has been determined at 2.4 Å resolution. The structure revealed that five dimers are arranged to form a ring. The stand-alone RAM (regulation of amino-acid metabolism) domain protein SraA from Thermus thermophilus HB8 (TTHA0845) was crystallized in the presence of zinc ions. The X-ray crystal structure was determined using a multiple-wavelength anomalous dispersion technique and was refined at 2.4 Å resolution to a final R factor of 25.0%. The monomeric structure is a βαββαβ fold and it dimerizes mainly through interactions between the antiparallel β-sheets. Furthermore, five SraA dimers form a ring with external and internal diameters of 70 and 20 Å, respectively. This decameric structure is unique compared with the octameric and dodecameric structures found for other stand-alone RAM-domain proteins and the C-terminal RAM domains of Lrp/AsnC-family proteins

  5. Structure of the minimized α/β-hydrolase fold protein from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The crystal structure of the minimized α/β-hydrolase fold protein encoded by the gene TTHA1544 from T. thermophilus HB8 has been determined at 2.0 Å resolution. The gene encoding TTHA1544 is a singleton found in the Thermus thermophilus HB8 genome and encodes a 131-amino-acid protein. The crystal structure of TTHA1544 has been determined at 2.0 Å resolution by the single-wavelength anomalous dispersion method in order to elucidate its function. There are two molecules in the asymmetric unit. Each molecule consists of four α-helices and six β-strands, with the β-strands composing a central β-sheet. A structural homology search revealed that the overall structure of TTHA1544 resembles the α/β-hydrolase fold, although TTHA1544 lacks the catalytic residues of a hydrolase. These results suggest that TTHA1544 represents the minimized α/β-hydrolase fold and that an additional component would be required for its activity

  6. Bioremediation potential of a newly isolate solvent tolerant strain Bacillus thermophilus PS11

    Directory of Open Access Journals (Sweden)

    PAYEL SARKAR

    2012-01-01

    Full Text Available The increased generation of solvent waste has been stated as one of the most critical environmental problems. Though microbial bioremediation has been widely used for waste treatment but their application in solvent waste treatment is limited since the solvents have toxic effects on the microbial cells. A solvent tolerant strain of Bacillus thermophilus PS11 was isolated from soil by cyclohexane enrichment. Transmission electron micrograph of PS11 showed convoluted cell membrane and accumulation of solvents in the cytoplasm, indicating the adaptation of the bacterial strain to the solvent after 48h of incubation. The strain was also capable of growing in presence of wide range of other hydrophobic solvents with log P-values below 3.5. The isolate could uptake 50 ng/ml of uranium in its initial 12h of growth, exhibiting both solvent tolerance and metal resistance property. This combination of solvent tolerance and metal resistance will make the isolated Bacillus thermophilus PS11 a potential tool for metal bioremediation in solvent rich wastewaters.

  7. Production of gamma-aminobutyric acid by Streptococcus salivarius subsp. thermophilus Y2 under submerged fermentation.

    Science.gov (United States)

    Yang, S-Y; Lü, F-X; Lu, Z-X; Bie, X-M; Jiao, Y; Sun, L-J; Yu, B

    2008-04-01

    Gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the central nervous system, has several well-known physiological functions and has been applied to the production of many drugs and functional foods. The technology of GABA production via submerged fermentation by Streptococcus salivarius subsp. thermophilus Y2 was investigated in this paper. It indicated that the GABA production was related to the biochemical characteristics of glutamate decarboxylase (GAD) of S. salivarius subsp. thermophilus Y2. After 24 h of fermentation at 37 degrees C, which is the suitable culture conditions for GAD-production, then the culture condition were adjusted to the optimal temperature (40 degrees C) and pH (4.5) for the GAD reaction activity in biotransformation of cells and pyridoxal 5'-phosphate (0.02 mmol/l) were added to the broth at the 48 h, the GABA production was increased up to 1.76-fold, reaching 7984.75 +/- 293.33 mg/l. The strain shows great potential use as a starter for GABA-containing yoghurt, cheese and other functional fermented food productions. PMID:17514494

  8. Structure of putative 4-amino-4-deoxychorismate lyase from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The putative 4-amino-4-deoxychorismate lyase (TTHA0621) from T. thermophilus HB8 was cloned, overexpressed, purified and crystallized. Its crystal structure was determined by a combination of SAD and molecular-replacement methods and was refined to 1.93 Å resolution. The pyridoxal 5′-phosphate-dependent enzyme 4-amino-4-deoxychorismate lyase converts 4-amino-4-deoxychorismate to p-aminobenzoate and pyruvate in one of the crucial steps in the folate-biosynthesis pathway. The primary structure of the hypothetical protein TTHA0621 from Thermus thermophilus HB8 suggests that TTHA0621 is a putative 4-amino-4-deoxychorismate lyase. Here, the crystal structure of TTHA0621 is reported at 1.93 Å resolution. The asymmetric unit contained four NCS molecules related by 222 noncrystallographic symmetry, in which the formation of intact dimers may be functionally important. The cofactor pyridoxal 5′-phosphate (PLP) binds to the protein in the large cleft formed by the N-terminal and C-terminal domains of TTHA0621. The high structural similarity and the conservation of the functional residues in the catalytic region compared with 4-amino-4-deoxychorismate lyase (PabC; EC 4.1.3.38) from Escherichia coli suggest that the TTHA0621 protein may also possess 4-amino-4-deoxychorismate lyase activity

  9. Evaluating acetaldehyde synthesis from L-/sup 14/C(U)) threonine by Streptococcus thermophilus and Lactobacillus bulgaricus

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, D.W.; Schmidt, R.H.; Shireman, R.B.; Smith, K.L.; Jezeski, J.J.

    1986-05-01

    To evaluate the synthesis of acetaldehyde from threonine during growth of yogurt cultures, Streptococcus thermophilus MS1 and Lactobacillus bulgaricus MR1 were grown in defined medium in which 10% of the total threonine was composed of L-(carbon-14(U))threonine. Acetaldehyde production was monitored by formation of 2,4-dinitrophenylhydrazone followed by separation and analysis using high performance liquid chromatography. After growth for 8 h at 42/sup 0/C, approximately 2.0% of the total acetaldehyde (780.4 nmol) produced was from L-(carbon-14)threonine. Threonine aldolase activity was determined in cell-free extracts from S. thermophilus and L. bulgaricus grown in Elliker broth. Increasing incubation temperature from 30 to 42/sup 0/C decreased threonine aldolase activity in cells of the streptococcus harvested after 8 h of incubation. Effect of incubation temperature was more dramatic in cells harvested after 18 h where the activity of cells grown at 48/sup 0/C was 89% lower than that of cells grown at 30/sup 0/C. Cell extracts from S. thermophilus MS1 possessed higher threonine aldolase activity than did those from L. bulgaricus MR1. Increased assay temperature from 30 to 42/sup 0/C increased threonine aldolase activity in S. thermophilus MS1.

  10. Correlation of Activities of the Enzymes α-Phosphoglucomutase, UDP-Galactose 4-Epimerase, and UDP-Glucose Pyrophosphorylase with Exopolysaccharide Biosynthesis by Streptococcus thermophilus LY03

    OpenAIRE

    Degeest, Bart; De Vuyst, Luc

    2000-01-01

    The effects of different carbohydrates or mixtures of carbohydrates as substrates on bacterial growth and exopolysaccharide (EPS) production were studied for the yoghurt starter culture Streptococcus thermophilus LY03. This strain produces two heteropolysaccharides with the same monomeric composition (galactose and glucose in the ratio 4:1) but with different molecular masses. Lactose and glucose were fermented by S. thermophilus LY03 only when they were used as sole energy and carbohydrate s...

  11. Characterization of the Function and Interaction of Proteins Involved in Exopolysaccharide Synthesis in Streptococcus thermophilus, Streptococcus iniae, and Lactococcus lactis subsp. cremoris

    OpenAIRE

    Cefalo, Angela D.

    2012-01-01

    Amino acid residues that are important for metal binding and catalysis in Grampositive phosphotyrosine phosphatases were identified in Streptococcus thermophilus Wzh/EpsB proteins. The Wzh protein from S. thermophilus MR-1C was purified after heterologous expression and tested for phosphatase activity against synthetic phosphotyrosine and phosphoserine/threonine peptides. The purified Wzh protein was able to remove phosphate from both phosphotyrosine peptides tested and the phosphatase activi...

  12. Reconstitution of translation from Thermus thermophilus reveals a minimal set of components sufficient for protein synthesis at high temperatures and functional conservation of modern and ancient translation components

    OpenAIRE

    Ying ZHOU; Asahara, Haruichi; Gaucher, Eric A.; Chong, Shaorong

    2012-01-01

    Thermus thermophilus is a thermophilic model organism distantly related to the mesophilic model organism E. coli. We reconstituted protein translation of Thermus thermophilus in vitro from purified ribosomes, transfer ribonucleic acids (tRNAs) and 33 recombinant proteins. This reconstituted system was fully functional, capable of translating natural messenger RNA (mRNA) into active full-length proteins at temperatures up to 65°C and with yields up to 60 μg/ml. Surprisingly, the synthesis of a...

  13. Assembling the Streptococcus thermophilus clustered regularly interspaced short palindromic repeats (CRISPR) array for multiplex DNA targeting.

    Science.gov (United States)

    Guo, Lijun; Xu, Kun; Liu, Zhiyuan; Zhang, Cunfang; Xin, Ying; Zhang, Zhiying

    2015-06-01

    In addition to the advantages of scalable, affordable, and easy to engineer, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) technology is superior for multiplex targeting, which is laborious and inconvenient when achieved by cloning multiple gRNA expressing cassettes. Here, we report a simple CRISPR array assembling method which will facilitate multiplex targeting usage. First, the Streptococcus thermophilus CRISPR3/Cas locus was cloned. Second, different CRISPR arrays were assembled with different crRNA spacers. Transformation assays using different Escherichia coli strains demonstrated efficient plasmid DNA targeting, and we achieved targeting efficiency up to 95% with an assembled CRISPR array with three crRNA spacers. PMID:25748774

  14. Expression, purification and characterization of recombinant protein tyrosine phosphatase from Thermus thermophilus HB27

    Institute of Scientific and Technical Information of China (English)

    Yejing Wang; Fanguo Meng; Yingmei Zhang

    2009-01-01

    The low-molecular-weight protein tyrosine phospha-tases (PTPase) exist ubiquitously in prokaryotes and eukaryotes and play important roles in the regulation of physiological activities. We report here the expression, purification and characterization of an active and soluble PTPase from Thermus thermophilus HB27 in Escherichia coli. This PTPase has an optimum pH range of 2.8-4.8 when using p-nitrophenyl phos-phate as the substrate. The thermal inactivation results indicate a high thermal stability of this enzyme, with the optimum temperature of 75℃ for activity. It can be activated by Mn2+, Mg2+, Ca2+, Ba2+, and Ni2+, but inhibited by Zn2+, Cu2+, Cl-, and SO2-4. These results suggest that this heat-resistant PTPase may play impor-tant roles in vivo in the adaptation of the microorgan-ism to extreme temperatures and specific nutritional conditions.

  15. Identification of lactobacillus casei-BDI and Streptococcus thermophilus by fluorescence spectra

    Institute of Scientific and Technical Information of China (English)

    Hao Wu; Tuo Zhu; Wei Chen; Hao Zhang; Jianlei Yang

    2009-01-01

    Fluorescence analysis applied in the study of lactic acid bacteria (LAB) provides a new method and theory to study probiotics and realize the detection and identification of the strains.It is also possible to achieve automation and computerization.In this letter,the differences between the fluorescence spectra of lactobacillus casei-BDI (Lc-BDI) and Streptococcus thermophilus (St) are shown,and the second-order derivative spectra are used to further study the diversity of these two strains.According to the results,with thc excitation wavelengths of 285 and 340 nm,there are significant differences between them.The experiment is repeated for 6 times,showing good repetitiveness.

  16. An efficient gene replacement and deletion system for an extreme thermophile, Thermus thermophilus.

    Science.gov (United States)

    Tamakoshi, M; Yaoi, T; Oshima, T; Yamagishi, A

    1999-04-15

    A Thermus thermophilus host strain of which the leuB gene was totally deleted was constructed from a delta pyrE strain by a two step method. First, the leuB gene was replaced with the pyrE gene. Second, the inserted pyrE gene was deleted by using 5-fluoroorotic acid. A plasmid vector with the leuB marker was constructed and the plasmid complemented the leuB deficiency of the host. When the leuB gene from Escherichia coli and its derivative encoding a stabilized enzyme were expressed with the host-vector system, their growth temperature reflected the stability of the enzyme. These results suggest that the gene replacement deletion method using the pyrE gene is useful for the construction of a reliable plasmid vector system and it can be applied to the selection of stabilized enzymes. PMID:10227171

  17. Properties of Streptococcus thermophilus fermented milk containing variable concentrations of Bifidobacterium longum and Lactobacillus acidophilus Propriedades de leites fermentados por Streptococcus thermophilus contendo concentrações variáveis de Bifidobacterium longum e Lactobacillus acidophilus

    Directory of Open Access Journals (Sweden)

    Patrícia Blumer Zacarchenco

    2006-09-01

    Full Text Available Sensory evaluation and analysis of pH, titratable acidity and microbial counts after 1, 7, 14 and 21 days of storage of five combinations of lyophilized Bifidobacterium longum and/or Lactobacillus acidophilus added to milk fermented with Streptococcus thermophilus were studied during storage at 4ºC. The taste and acidity sensory attributes were significantly (PForam estudadas as características sensoriais, de pH e acidez de cinco combinações de leites fermentados por Streptococcus thermophilus, adicionados de Bifidobacterium longum e/ou Lactobacillus acidophilus liofilizados. Os efeitos sobre as características sensoriais tornaram-se significantes (p < 0,05 com o aumento do tempo de estocagem. As combinações favoritas continham, inicialmente, Bif. longum e L. acidophilus (10(8 e 10(7ufc/mL, respectivamente e Bif. longum apenas (10(8ufc/mL. Estas combinações não diferiram significativamente do leite fermentado padrão, nem entre si. As notas mais baixas e os maiores valores de acidez titulável foram apresentados pelo leite fermentado por Streptococcus thermophilus contendo apenas L. acidophilus (10(8ufc/mL, concentração inicial. Durante 21 dias de estocagem a 4ºC, as contagens de células viáveis de Str. thermophilus não mudaram, as de Bif. longum mantiveram-se constantes ou reduziram em um ciclo logarítmico e, as de L. acidophilus reduziram de 1 a 2 ciclos logarítmicos. Não foi observada inibição da pós-acidificação resultante da presença de bifidobactéria ou L. acidophilus.

  18. Purification, crystallization and preliminary X-ray analysis of the fumarylacetoacetase family member TTHA0809 from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The putative fumarylacetoacetase TTHA0809 from T. thermophilus HB8 has been overexpressed, purified and crystallized. The crystals diffracted X-rays to 2.2 Å resolution using synchrotron radiation. Fumarylacetoacetase catalyzes the final step of tyrosine and phenylalanine catabolism. A recombinant form of the fumarylacetoacetase family member TTHA0809 from Thermus thermophilus HB8 has been crystallized by the oil-microbatch method using sodium chloride as a precipitating agent. The crystals belong to the monoclinic space group P21, with unit-cell parameters a = 93.3, b = 73.4, c = 122.6 Å, β = 111.8°. The crystals are most likely to contain two dimers in the asymmetric unit, with a VM value of 3.32 Å3 Da−1. Diffraction data were collected at 2.2 Å resolution using synchrotron radiation at beamline BL26B1 of SPring-8, Japan

  19. Expression in E. coli and purification of Thermus thermophilus translation initiation factors IF1 and IF3.

    Science.gov (United States)

    Wolfrum, Alexandra; Brock, Stephan; Mac, Thi; Grillenbeck, Norbert

    2003-05-01

    The initiation of protein translation in bacteria requires in addition to mRNA, fMet-tRNA, and ribosomal subunits three protein factors, the initiation factor 1 (IF1), initiation factor 2 (IF2), and initiation factor 3 (IF3). The genes coding for IF1 and IF3 from Thermus thermophilus have been identified and cloned into pET expression vector and were expressed as soluble proteins in Escherichia coli. IF1 was purified by a DEAE-cellulose chromatography, followed by heat denaturation, chromatography on Hydroxylapatit, and gel permeation chromatography using Sephacryl 200HR. For the purification of IF3, a heat denaturation step is followed by anion-exchange chromatography on Q-Sepharose FF and gel permeation chromatography on Sephacryl 200HR. Using these procedures we obtained chromatographically pure and biologically active preparations of both T. thermophilus IF1 and IF3. PMID:12729721

  20. Structure of TTHA1623, a novel metallo-β-lactamase superfamily protein from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The crystal structures of TTHA1623 from T. thermophilus HB8 in an iron-bound and a zinc-bound form have been determined to 2.8 and 2.2 Å resolution, respectively. TTHA1623 is a metallo-β-lactamase superfamily protein from the extremely thermophilic bacterium Thermus thermophilus HB8. Homologues of TTHA1623 exist in a wide range of bacteria and archaea and one eukaryote, Giardia lamblia, but their function remains unknown. To analyze the structural properties of TTHA1623, the crystal structures of its iron-bound and zinc-bound forms have been determined to 2.8 and 2.2 Å resolution, respectively. TTHA1623 possesses an αββα-fold similar to that of other metallo-β-lactamase superfamily proteins with glyoxalase II-type metal coordination. However, TTHA1623 exhibits a putative substrate-binding pocket with a unique shape

  1. Cloning, expression, purification, crystallization and initial crystallographic analysis of the preprotein translocation ATPase SecA from Thermus thermophilus

    International Nuclear Information System (INIS)

    The SecA ATPase from T. thermophilus was cloned, expressed, purified and crystallized. Complete diffraction data sets were collected for two crystal forms at 2.8 and 3.5 Å resolution, respectively. Determination of the structure is now in progress. The Thermus thermophilus gene encoding the preprotein translocation ATPase SecA was cloned and expressed and the purified protein was crystallized by the hanging-drop vapour-diffusion technique in two different space groups P31(2)21 (a = b = 168.6, c = 149.8 Å) and P61(5)22 (a = b = 130.9, c = 564.6 Å). The crystals, improved by macroseeding, diffracted to beyond 2.8 and 3.5 Å resolution for the trigonal and hexagonal crystal forms, respectively. Structure determination using the multiple isomorphous replacement method is in progress

  2. Phage-induced expression of CRISPR-associated proteins is revealed by shotgun proteomics in Streptococcus thermophilus.

    Directory of Open Access Journals (Sweden)

    Jacque C Young

    Full Text Available The CRISPR/Cas system, comprised of clustered regularly interspaced short palindromic repeats along with their associated (Cas proteins, protects bacteria and archaea from viral predation and invading nucleic acids. While the mechanism of action for this acquired immunity is currently under investigation, the response of Cas protein expression to phage infection has yet to be elucidated. In this study, we employed shotgun proteomics to measure the global proteome expression in a model system for studying the CRISPR/Cas response in S. thermophilus DGCC7710 infected with phage 2972. Host and viral proteins were simultaneously measured following inoculation at two different multiplicities of infection and across various time points using two-dimensional liquid chromatography tandem mass spectrometry. Thirty-seven out of forty predicted viral proteins were detected, including all proteins of the structural virome and viral effector proteins. In total, 1,013 of 2,079 predicted S. thermophilus proteins were detected, facilitating the monitoring of host protein synthesis changes in response to virus infection. Importantly, Cas proteins from all four CRISPR loci in the S. thermophilus DGCC7710 genome were detected, including loci previously thought to be inactive. Many Cas proteins were found to be constitutively expressed, but several demonstrated increased abundance following infection, including the signature Cas9 proteins from the CRISPR1 and CRISPR3 loci, which are key players in the interference phase of the CRISPR/Cas response. Altogether, these results provide novel insights into the proteomic response of S. thermophilus, specifically CRISPR-associated proteins, upon phage 2972 infection.

  3. Characterization and evolution of a family of integrative and potentially conjugative or mobilizable elements from Streptococcus thermophilus

    OpenAIRE

    Pavlovic, Guillaume; Burrus, Vincent; Toulmay, Alexandre; Choulet, Frédéric; Decaris, Bernard; Guédon, Gérard

    2004-01-01

    International audience The integrative and conjugative elements (ICEs) excise by site-specific recombination, self-transfer the resulting circular form by conjugation and integrate into the genome of the recipient bacterium. The 34.7-kb element from Streptococcus thermophilus CNRZ368, ICESt1, excises and integrates by site-specific recombination. This element also possesses a conjugation module distantly related to that of the conjugative transposon Tn916 from Enterococcus faecalis. Theref...

  4. A Novel Heme a Insertion Factor Gene Cotranscribes with the Thermus thermophilus Cytochrome ba3 Oxidase Locus▿

    OpenAIRE

    Werner, Carolin; Richter, Oliver-Matthias H.; Ludwig, Bernd

    2010-01-01

    Studying the biogenesis of the Thermus thermophilus cytochrome ba3 oxidase, we analyze heme a cofactor insertion into this membrane protein complex. Only three proteins linked to oxidase maturation have been described for this extreme thermophile, and in particular, no evidence for a canonical Surf1 homologue, required for heme a insertion, is available from genome sequence data. Here, we characterize the product of an open reading frame, cbaX, in the operon encoding subunits of the ba3-type ...

  5. Phage-Induced Expression of CRISPR-Associated Proteins is Revealed by Shotgun Proteomics in Streptococcus thermophilus

    Energy Technology Data Exchange (ETDEWEB)

    Young, Jacque C [ORNL; Dill, Brian [ORNL; Pan, Chongle [ORNL; Hettich, Robert {Bob} L [ORNL; Banfield, Jillian F. [University of California, Berkeley; Shah, Manesh B [ORNL; Fremaux, Christophe [Danisco France SAS; Horvath, Philippe [Danisco France SAS; Barrangou, Rodolphe [Danisco USA; Verberkmoes, Nathan C [ORNL

    2012-01-01

    The CRISPR/Cas system, comprised of clustered regularly interspaced short palindromic repeats along with their associated (Cas) proteins, protects bacteria and archaea from viral predation and invading nucleic acids. While the mechanism of action for this acquired immunity is currently under investigation, the response of Cas protein expression to phage infection has yet to be elucidated. In this study, we employed shotgun proteomics to measure the global proteome expression in a model system for studying the CRISPR/Cas response: infection of S. thermophilus DGCC7710 with phage 2972. Host and viral proteins were simultaneously measured following inoculation at two different multiplicities of infection and across various time points using two-dimensional liquid chromatography tandem mass spectroscopy. Thirty-seven out of forty predicted viral proteins were detected, including all proteins of the structural virome and viral effector proteins. In total, 1,013 of 2,079 predicted S. thermophilus proteins were detected, facilitating the monitoring of host protein synthesis changes in response to virus infection. Importantly, Cas proteins from all four CRISPR loci in the S. thermophilus DGCC7710 genome were detected, including loci previously thought to be inactive. Many Cas proteins were found to be constitutively expressed, but several demonstrated increased abundance during peak infection, including the Cas9 proteins from the CRISPR1 and CRISPR3 loci, which are key players in the interference phase of the CRISPR/Cas response. Altogether, these results provide novel insights into the proteomic response of S. thermophilus, specifically CRISPR-associated proteins, upon phage 2972 infection.

  6. Purification, properties, and sequence specificity of SslI, a new type II restriction endonuclease from Streptococcus salivarius subsp. thermophilus.

    Science.gov (United States)

    Benbadis, L; Garel, J R; Hartley, D L

    1991-01-01

    SslI, a type II restriction endonuclease, was purified from Streptococcus salivarius subsp. thermophilus strain BSN 45. SslI is an isoschizomer of BstNI. SslI activity was maximum at pH 8.8, 0 to 50 mM NaCl, 2 to 8 mM Mg2+, and 42 degrees C. Activity against phage DNA in vitro was demonstrated. Images PMID:1785940

  7. Mixed-culture transcriptome analysis reveals the molecular basis of mixed-culture growth in Streptococcus thermophilus and Lactobacillus bulgaricus

    OpenAIRE

    Sieuwerts, S.; Molenaar, D; Hijum, van, S.A.F.T.; Beerthuyzen, M.; Stevens, M.J.A.; Janssen, P.W.; Ingham, C J; Bok, de, F.A.M.; Vos, de, W.M.; Hylckama Vlieg, van, J.E.T.

    2010-01-01

    Many food fermentations are performed using mixed cultures of lactic acid bacteria. Interactions between strains are of key importance for the performance of these fermentations. Yogurt fermentation by Streptococcus thermophilus and Lactobacillus bulgaricus (basonym, Lactobacillus delbrueckii subsp. bulgaricus) is one of the best-described mixed-culture fermentations. These species are believed to stimulate each other's growth by the exchange of metabolites such as folic acid and carbon dioxi...

  8. Cloning, expression, purification, crystallization and preliminary X-ray crystallographic study of molybdopterin synthase from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The molybdopterin synthase from T. thermophilus HB8 was cloned, expressed, purified and crystallized. The crystals belong to space group P21 and diffracted to a resolution of 1.64 Å. Thermus thermophilus is a Gram-negative aerobic thermophilic eubacterium which can grow at temperatures ranging from 323 to 355 K. In addition to their importance in thermostability or adaptation strategies for survival at high temperatures, the thermostable enzymes in thermophilic organisms contribute to a wide range of biotechnological applications. The molybdenum cofactor in all three kingdoms consists of a tricyclic pyranopterin termed molybdopterin that bears the cis-dithiolene group responsible for molybdenum ligation. The crystals of molybdopterin synthase from T. thermophilus HB8 belong to the primitive monoclinic space group P21, with unit-cell parameters a = 33.94, b = 103.32, c = 59.59 Å, β = 101.3°. Preliminary studies and molecular-replacement calculations reveal the presence of three monomers in the asymmetric unit

  9. Site-directed mutation of a laccase from Thermus thermophilus: Effect on the activity profile

    Directory of Open Access Journals (Sweden)

    Liu Xin

    2012-01-01

    Full Text Available A site-directed mutant R453T of a laccase from Thermus thermophilus HB27 (Tth-laccase was constructed in order to investigate the effect on laccase catalytic properties. The mutated gene was cloned and overexpressed in Escherichia coli. Nickel-affinity purification was achieved and followed by copper ion incorporation. The mature mutated enzyme was quantitatively equal to the wild type. A photometric assay based on the oxidation of the substrate 2,2-azino-bis-(3- ethylbenzthiazoline-6-sulfonate (ABTS was employed in comparison with the wild-type Tth-laccase on catalytic properties. The R453T mutant exhibited improvement in substrate affinity and specific activity at room temperature, whereas those parameters were not significantly influenced when the temperature increased up to 65°C or higher. The mutant had better catalytic activity than that of the wild type at acidic pH. Investigated by circular dichroism spectroscopy, the mutant Tth-laccase displayed similar profiles at low and high temperatures.

  10. Expression and Characterization of Recombinant Thermostable Alkaline Phosphatase from a Novel Thermophilic Bacterium Thermus thermophilus XM

    Institute of Scientific and Technical Information of China (English)

    Jianbo LI; Limei XU; Feng YANG

    2007-01-01

    A gene (tap) encoding a thermostable alkaline phosphatase from the thermophilic bacterium Thermus thermophilus XM was cloned and sequenced. It is 1506 bp long and encodes a protein of 501 amino acid residues with a calculated molecular mass of 54.7 kDa. Comparison of the deduced amino acid sequence with other alkaline phosphatases showed that the regions in the vicinity of the phosphorylation site and metal binding sites are highly conserved. The recombinant thermostable alkaline phosphatase was expressed as a His6-tagged fusion protein in Escherichia coli and its enzymatic properties were characterized after purification. The pH and temperature optima for the recombinant thermostable alkaline phosphatases activity were pH 12 and 75 ℃. As expected, the enzyme displayed high thermostability, retaining more than 50% activity after incubating for 6 h at 80 ℃. Its catalytic function was accelerated in the presence of 0.1 mM Co2+, Fe2+, Mg2+, or Mn2+ but was strongly inhibited by 2.0 mM Fe2+. Under optimal conditions, the Michaelis constant (Km) for cleavage of p-nitrophenyl-phosphate was 0.034 mM. Although it has much in common with other alkaline phosphatases, the recombinant thermostable alkaline phosphatase possesses some unique features, such as high optimal pH and good thermostability.

  11. Long-Range PCR Amplification of DNA by DNA Polymerase III Holoenzyme from Thermus thermophilus

    Directory of Open Access Journals (Sweden)

    Wendy Ribble

    2015-01-01

    Full Text Available DNA replication in bacteria is accomplished by a multicomponent replicase, the DNA polymerase III holoenzyme (pol III HE. The three essential components of the pol III HE are the α polymerase, the β sliding clamp processivity factor, and the DnaX clamp-loader complex. We report here the assembly of the functional holoenzyme from Thermus thermophilus (Tth, an extreme thermophile. The minimal holoenzyme capable of DNA synthesis consists of α, β and DnaX (τ and γ, δ and δ′ components of the clamp-loader complex. The proteins were each cloned and expressed in a native form. Each component of the system was purified extensively. The minimum holoenzyme from these five purified subunits reassembled is sufficient for rapid and processive DNA synthesis. In an isolated form the α polymerase was found to be unstable at temperatures above 65°C. We were able to increase the thermostability of the pol III HE to 98°C by addition and optimization of various buffers and cosolvents. In the optimized buffer system we show that a replicative polymerase apparatus, Tth pol III HE, is capable of rapid amplification of regions of DNA up to 15,000 base pairs in PCR reactions.

  12. Structural analysis of the exopolysaccharide produced by Streptococcus thermophilus ST1 solely by NMR spectroscopy

    International Nuclear Information System (INIS)

    The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT experiments. The EPS is composed of hexasaccharide repeating units with the following structure: → 3)[α-d-Glcp-(1 → 4)]-β-d-Galp-(1 → 4)-β-d-Glcp-(1 → 4)[β-d-Galf-(1 → 6)]-β-d-Glcp-(1 → 6)-β-d-Glcp-(1 →, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined using translational diffusion experiments which resulted in Mw = 62 kDa, corresponding to 64 repeating units in the EPS.

  13. Structural analysis of the exopolysaccharide produced by Streptococcus thermophilus ST1 solely by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Saewen, Elin [Arrhenius Laboratory, Stockholm University, Department of Organic Chemistry (Sweden); Huttunen, Eine; Zhang Xue [University of Helsinki, Department of Food Technology (Finland); Yang Zhennai [Northeast Agricultural Research Center of China, Center of Agro-food Technology (China); Widmalm, Goeran, E-mail: gw@organ.su.s [Arrhenius Laboratory, Stockholm University, Department of Organic Chemistry (Sweden)

    2010-06-15

    The use of lactic acid bacteria in fermentation of milk results in favorable physical and rheological properties due to in situ exopolysaccharide (EPS) production. The EPS from S. thermophilus ST1 produces highly viscous aqueous solutions and its structure has been investigated by NMR spectroscopy. Notably, all aspects of the elucidation of its primary structure including component analysis and absolute configuration of the constituent monosaccharides were carried out by NMR spectroscopy. An array of techniques was utilized including, inter alia, PANSY and NOESY-HSQC TILT experiments. The EPS is composed of hexasaccharide repeating units with the following structure: {yields} 3)[{alpha}-d-Glcp-(1 {yields} 4)]-{beta}-d-Galp-(1 {yields} 4)-{beta}-d-Glcp-(1 {yields} 4)[{beta}-d-Galf-(1 {yields} 6)]-{beta}-d-Glcp-(1 {yields} 6)-{beta}-d-Glcp-(1 {sup {yields}}, in which the residues in square brackets are terminal groups substituting backbone sugar residues that consequently are branch-points in the repeating unit of the polymer. Thus, the EPS consists of a backbone of four sugar residues with two terminal sugar residues making up two side-chains of the repeating unit. The molecular mass of the polymer was determined using translational diffusion experiments which resulted in M{sub w} = 62 kDa, corresponding to 64 repeating units in the EPS.

  14. Heterologous Expression of an Alkali and Thermotolerant Lipase from Talaromyces thermophilus in Trichoderma reesei.

    Science.gov (United States)

    Zhang, Xu; Li, Xueqi; Xia, Liming

    2015-07-01

    To heterologously express a Talaromyces thermophilus lipase gene in Trichoderma reesei, an efficient binary vector pChph-pCBH1sigpro-ttl which includes a newly designed cbh1 promoter and hygromycin-resistant marker was constructed. This plasmid was then transformed into T. reesei via improved Agrobacterium EHA 105-mediated transformation. After modification of co-culture conditions and enzymolysis treatment of conidia, 258 transformants were produced. A two-step screening method based on antibiotic resistance and capacity to utilize lactose and tributyrin was introduced to further select promising candidates, which would be additionally verified by PCR analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and lipase activity assay. Lipase production was carried out in shaking flasks, and the activity reached 241 IU/mL (7415.4 IU/mg) after 84-h fermentation. It was found that this lipase performed high alkali and thermostable tolerance with the optimal pH 9.5 and temperature 60 °C, and it could retain more than 70 % activity after being disposed in pH 11 or 70 °C for 1 h. This study herein would benefit the genetic engineering of T. reesei and the industrial application of this important fungal lipase. PMID:26077681

  15. A novel pheromone quorum-sensing system controls the development of natural competence in Streptococcus thermophilus and Streptococcus salivarius.

    Science.gov (United States)

    Fontaine, Laetitia; Boutry, Céline; de Frahan, Marie Henry; Delplace, Brigitte; Fremaux, Christophe; Horvath, Philippe; Boyaval, Patrick; Hols, Pascal

    2010-03-01

    In streptococcal species, the key step of competence development is the transcriptional induction of comX, which encodes the alternative sigma factor sigma(X), 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. PMID:20023010

  16. A Novel Pheromone Quorum-Sensing System Controls the Development of Natural Competence in Streptococcus thermophilus and Streptococcus salivarius▿ †

    Science.gov (United States)

    Fontaine, Laetitia; Boutry, Céline; de Frahan, Marie Henry; Delplace, Brigitte; Fremaux, Christophe; Horvath, Philippe; Boyaval, Patrick; Hols, Pascal

    2010-01-01

    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. PMID:20023010

  17. Identification of novel esterase-active enzymes from hot environments by use of the host bacterium Thermus thermophilus

    Directory of Open Access Journals (Sweden)

    Benedikt eLeis

    2015-04-01

    Full Text Available Functional metagenomic screening strategies, which are independent of known sequence information, can lead to the identification of truly novel genes and enzymes. Since E. coli has been used exhaustively for this purpose as a host, it is important to establish alternative expression hosts and to use them for functional metagenomic screening for new enzymes. In this study we show that Thermus thermophilus HB27 is an excellent screening host and can be used as an alternative provider of truly novel biocatalysts. In a previous study we constructed the mutant strain BL03 that was no longer able to grow on defined minimal medium supplemented with tributyrin as the sole carbon source and could be used as a host to screen for metagenomic DNA fragments that could complement growth on tributyrin. Several thousand single fosmid clones from thermophilic metagenomic libraries from heated compost and hot spring water samples were subjected to a comparative screening for esterase activity in both T. thermophilus strain BL03 and E. coli EPI300. We scored a greater number of active clones in the thermophilic bacterium than in the mesophilic E. coli. From all clones functionally screened in E. coli, only two thermostable α/β-fold hydrolase enzymes with high amino acid sequence similarity to already characterized enzymes were identifiable. In contrast, five further fosmids were found that conferred lipolytic activities in T. thermophilus. Four open reading frames (ORFs were found which did not share significant similarity to known esterase enzymes. Two of the genes were expressed in both hosts and the novel thermophilic esterases, which based on their primary structures could not be assigned to known esterase or lipase families, were purified and preliminarily characterized. Our work underscores the benefit of using additional screening hosts other than E. coli for the identification of novel biocatalysts with industrial relevance.

  18. High yield of mannosylglycerate production by upshock fermentation and bacterial milking of trehalose-deficient mutant Thermus thermophilus RQ-1

    OpenAIRE

    K Egorova; Grudieva, T.; Morinez, C.; Kube, J.; Santos, H.; Costa, M Da; Antranikian, G.

    2007-01-01

    Abstract A production process, using upshock fermentation and osmotic downshock, for the effective production/excretion of mannosylglycerate (MG) by the trehalose-deficient mutant of the strain Thermus thermophilus RQ-1 has been developed. In the first phase of fed-batch fermentation, the knockout mutant was grown at 70°C on a NaCl-free medium. After the culture reached the end of the exponential growth phase, upshift in temperature and NaCl concentration was applied. The temperature was inc...

  19. Röntgenstrukturanalyse der ba3 Cytochrom-c Oxidase aus Thermus thermophilus und ihres Substrates Cytochrom-c552

    OpenAIRE

    Than, Manuel E.

    2007-01-01

    Die dreidimensionalen Strukturen der ba3 Cytocrom-c Oxidase aus dem Eubakterium Thermus thermophilus sowie ihres Substrates Cytochrom-c552 wurden mit den Methoden der Röntgenstrukturanalyse bei einer Auflösung von 2,4 Å bzw. 1,28 Å aufgeklärt. Die Analyse dieser Strukturen ermöglichte das Verständnis der besonderen biochemischen Eigenschaften dieser beiden Proteine bezüglich Thermostabilität, Protonenpumpaktivität, Reaktionsmechanismus und Elektronenübertragung im Vergleich zu typischen Vert...

  20. Sequencing and transcriptional analysis of the Streptococcus thermophilus histamine biosynthesis gene cluster: factors that affect differential hdcA expression

    DEFF Research Database (Denmark)

    Calles-Enríquez, Marina; Hjort, Benjamin Benn; Andersen, Pia Skov;

    2010-01-01

    produce histamine. The hdc clusters of S. thermophilus CHCC1524 and CHCC6483 were sequenced, and the factors that affect histamine biosynthesis and histidine-decarboxylating gene (hdcA) expression were studied. The hdc cluster began with the hdcA gene, was followed by a transporter (hdcP), and ended with...... the hdcB gene, which is of unknown function. The three genes were orientated in the same direction. The genetic organization of the hdc cluster showed a unique organization among the lactic acid bacterial group and resembled those of Staphylococcus and Clostridium species, thus indicating possible...

  1. The three major types of CRISPR-Cas systems function independently in CRISPR RNA biogenesis in Streptococcus thermophilus

    OpenAIRE

    Carte, Jason; Christopher, Ross T.; Smith, Justin T.; Olson, Sara; Barrangou, Rodolphe; Moineau, Sylvain; Glover, Claiborne V. C.; Graveley, Brenton R.; Terns, Rebecca M.; Terns, Michael P.

    2014-01-01

    CRISPR-Cas systems are small RNA-based immune systems that protect prokaryotes from invaders such as viruses and plasmids. We have investigated the features and biogenesis of the CRISPR (cr)RNAs in Streptococcus thermophilus (Sth) strain DGCC7710, which possesses four different CRISPR-Cas systems including representatives from the three major types of CRISPR-Cas systems. Our results indicate that the crRNAs from each CRISPR locus are specifically processed into divergent crRNA species by Cas ...

  2. Zygote-mediated generation of genome-modified mice using Streptococcus thermophilus 1-derived CRISPR/Cas system.

    Science.gov (United States)

    Fujii, Wataru; Kakuta, Shigeru; Yoshioka, Shin; Kyuwa, Shigeru; Sugiura, Koji; Naito, Kunihiko

    2016-08-26

    Mammalian zygote-mediated genome-engineering by CRISPR/Cas is currently used for the generation of genome-modified animals. Here we report that a Streptococcus thermophilus-1 derived orthologous CRISPR/Cas system, which recognizes the 5'-NNAGAA sequence as a protospacer adjacent motif (PAM), is useful in mouse zygotes and is applicable for generating knockout mice (87.5%) and targeted knock-in mice (45.5%). The induced mutation could be inherited in the next generation. This novel CRISPR/Cas can expand the feasibility of the zygote-mediated generation of genome-modified animals that require an exact mutation design. PMID:27318086

  3. Crystal structure of phenylacetic acid degradation protein PaaG from Thermus thermophilus HB8.

    Science.gov (United States)

    Kichise, Tomoyasu; Hisano, Tamao; Takeda, Kazuki; Miki, Kunio

    2009-09-01

    Microbial degradation of phenylacetic acid proceeds via the hybrid pathway that includes formation of a coenzyme A thioester, ring hydroxylation, non-oxygenolytic ring opening, and beta-oxidation-like reactions. A phenylacetic acid degradation protein PaaG is a member of the crotonase superfamily, and is a candidate non-oxygenolytic ring-opening enzyme. The crystal structure of PaaG from Thermus thermophilus HB8 was determined at a resolution of 1.85 A. PaaG consists of three identical subunits related by local three-fold symmetry. The monomer is comprised of a spiral and a helical domain with a fold characteristic of the crotonase superfamily. A putative active site residue, Asp136, is situated in an active site cavity and surrounded by several hydrophobic and hydrophilic residues. The active site cavity is sufficiently large to accommodate a ring substrate. Two conformations are observed for helix H2 located adjacent to the active site. Helix H2 is kinked at Asn81 in two subunits, whereas it is kinked at Leu77 in the other subunit, and the side chain of Tyr80 is closer to Asp136. This indicates that catalytic reaction of PaaG may proceed with large conformational changes at the active site. Asp136 is the only conserved polar residue in the active site. It is located at the same position as those of 4-chlorobenzoyl-CoA dehalogenase and peroxisomal Delta(3),Delta(2)-enoyl-CoA isomerase, indicating that PaaG may undergo isomerization or a ring-opening reaction via a Delta(3),Delta(2)-enoyl-CoA isomerase-like mechanism. PMID:19452559

  4. Crystal structure studies of NADP+ dependent isocitrate dehydrogenase from Thermus thermophilus exhibiting a novel terminal domain

    International Nuclear Information System (INIS)

    Highlights: • We determined the structure of isocitrate dehydrogenase with citrate and cofactor. • The structure reveals a unique novel terminal domain involved in dimerization. • Clasp domain shows significant difference, and catalytic residues are conserved. • Oligomerization of the enzyme is quantized with subunit-subunit interactions. • Novel domain of this enzyme is classified as subfamily of the type IV. - Abstract: NADP+ dependent isocitrate dehydrogenase (IDH) is an enzyme catalyzing oxidative decarboxylation of isocitrate into oxalosuccinate (intermediate) and finally the product α-ketoglutarate. The crystal structure of Thermus thermophilus isocitrate dehydrogenase (TtIDH) ternary complex with citrate and cofactor NADP+ was determined using X-ray diffraction method to a resolution of 1.80 Å. The overall fold of this protein was resolved into large domain, small domain and a clasp domain. The monomeric structure reveals a novel terminal domain involved in dimerization, very unique and novel domain when compared to other IDH’s. And, small domain and clasp domain showing significant differences when compared to other IDH’s of the same sub-family. The structure of TtIDH reveals the absence of helix at the clasp domain, which is mainly involved in oligomerization in other IDH’s. Also, helices/beta sheets are absent in the small domain, when compared to other IDH’s of the same sub family. The overall TtIDH structure exhibits closed conformation with catalytic triad residues, Tyr144-Asp248-Lys191 are conserved. Oligomerization of the protein is quantized using interface area and subunit–subunit interactions between protomers. Overall, the TtIDH structure with novel terminal domain may be categorized as a first structure of subfamily of type IV

  5. AcEST: BP918368 [AcEST

    Lifescience Database Archive (English)

    Full Text Available YMU001_000112_F10 559 Adiantum capillus-veneris mRNA. clone: YMU001_000112_F10. BP918368 - Show ... 2A810|B2A810_NATTJ Peptide chain release factor 2 (BRF -2) OS... 34 6.2 tr|Q4XUR1|Q4XUR1_PLACH Putative un ... 2A810|B2A810_NATTJ Peptide chain release factor 2 (BRF -2) OS=Natranaerobius thermophilus (strain ATCC BAA ...

  6. Expression, crystallization and preliminary X-ray analysis of a ferric binding protein from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    The cloning, expression, purification, crystallization and preliminary X-ray analysis of a ferric binding protein encoded by T. thermophilus HB8 in apo and iron-bound holo states are presented. Four different crystal forms were obtained. A ferric binding protein from Thermus thermophilus HB8 (TtFbpA) was expressed, purified and crystallized using the hanging-drop vapour-diffusion method. Four different crystal forms were obtained and characterized by X-ray diffraction. Two crystal forms with TtFbpA in the apo state belonged to the orthorhombic space group P212121 (unit-cell parameters a = 42.1, b = 139.3, c = 326.5 Å and a = 42.1, b = 139.3, c = 218.9 Å). The third form with TtFbpA also in the apo state belonged to the monoclinic space group P21 (unit-cell parameters a = 66.5, b = 61.7, c = 73.9 Å, β = 111.7°). The fourth form, with TtFbpA in the iron-bound holo state as confirmed by an atomic absorption spectrophotometry assay, belonged to the trigonal space group P3121 or P3221 (unit-cell parameters a = 63.6, b = 63.6, c = 266.7 Å, α = β = 90.0, γ = 120.0°)

  7. Study on Streptococcus thermophilus isolated from Qula and associated characteristic of acetaldehyde and diacetyl in their fermented milk.

    Science.gov (United States)

    Zha, Musu; Yu, Jie; Zhang, Yong; Wang, Hongmei; Bai, Na; Qin, Yanting; Liangliang, De; Liu, Wenjun; Zhang, Heping; Bilige, Menghe

    2015-01-01

    In this study, the lactic acid bacterial population of Qula cheese from the Gansu and Sichuan provinces of China were isolated and identified. Eight strains of Streptococcus thermophilus were isolated, of which five strains were selected for further characterization based on their fermentation properties. The changes in a number of parameters, including titration acidity, pH, viable counts, PrtS protease activity and the production of acetaldehyde, diacetyl and organic acid, were monitored during fermentation and the storage of fermented milks produced by the respective strain. All of the strains displaying acidifying capacity and all five fermented milks maintained high viable counts of S. thermophilus from fermentation to storage. Our study found that the changes in the monitored parameters were strain-specific and varied considerably among the five tested strains. Fermented milks produced by strain IMAU80809 had the highest concentration of acetaldehyde and were most favorable in the sensory evaluation. This study confirms that Qula cheese is a good source for isolating novel lactic acid bacterial strains with different fermentation properties, which will be very useful for further development and industrialization of traditionally fermented dairy products. PMID:26018501

  8. Optimization and effect of dairy industrial waste as media components in the production of hyaluronic acid by Streptococcus thermophilus.

    Science.gov (United States)

    Mohan, Naresh; Balakrishnan, Rengesh; Sivaprakasam, Senthilkumar

    2016-08-17

    Hyaluronic acid (HA) production using a dairy industrial waste is a more cost-efficient strategy than using an expensive synthetic medium. In this study, we investigated the production of HA using Streptococcus thermophilus under shake flask conditions using dairy industrial waste as nutritional supplements, namely whey permeate (WP) and whey protein hydrolysate (WPH). Preliminary screening using Plackett-Burman design exhibited WP, WPH, initial pH, and inoculum size as significant factors influencing HA titer. Response surface methodology design of four factors was formulated at three levels for enhanced production of HA. Shake flask HA fermentation by S. thermophilus was performed under global optimized process conditions and the optimal HA titer (342.93 mg L(-1)) corroborates with Box-Behnken design prediction. The molecular weight of HA was elucidated as 9.22-9.46 kDa. The ultralow-molecular weight HA reported in this study has a potential role in drug and gene delivery applications. PMID:26681350

  9. Crystallization and preliminary X-ray analysis of peptidyl-tRNA hydrolase from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    Peptidyl-tRNA hydrolase from T. thermophilus has been expressed, purified and crystallized. The crystals diffracted X-rays to atomic resolution (beyond 1.0 Å resolution). Peptidyl-tRNA is produced from the ribosome as a result of aborted translation. Peptidyl-tRNA hydrolase cleaves the ester bond between the peptide and the tRNA of peptidyl-tRNA molecules, to recycle tRNA for further rounds of protein synthesis. In this study, peptidyl-tRNA hydrolase from Thermus thermophilus HB8 (TthPth) was crystallized using 2-methyl-2,4-pentanediol as a precipitant. The crystals belonged to the orthorhombic space group P212121, with unit-cell parameters a = 47.45, b = 53.92, c = 58.67 Å, and diffracted X-rays to atomic resolution (beyond 1.0 Å resolution). The asymmetric unit is expected to contain one TthPth molecule, with a solvent content of 27.13% (VM = 1.69 Å3 Da−1). The structure is being solved by molecular replacement

  10. Draft Genome Sequences of Methanoculleus horonobensis Strain JCM 15517, Methanoculleus thermophilus Strain DSM 2373, and Methanofollis ethanolicus Strain JCM 15103, Hydrogenotrophic Methanogens Belonging to the Family Methanomicrobiaceae

    Science.gov (United States)

    Kusada, Hiroyuki; Yoneda, Yasuko; Tamaki, Hideyuki

    2016-01-01

    The family Methanomicrobiaceae comprises hydrogen- and formate-utilizing methanogens. Genome sequencing of nine species of Methanomicrobiaceae has been conducted so far. Here, we report three additional draft genome sequences of Methanomicrobiaceae, those of Methanoculleus horonobensis JCM 15517 (=T10T), Methanoculleus thermophilus DSM 2373 (=CR-1T), and Methanofollis ethanolicus JCM 15103 (=HASUT). PMID:27034500

  11. Mutations in conserved helix 69 of 23S rRNA of Thermus thermophilus that affect capreomycin resistance but not posttranscriptional modifications

    DEFF Research Database (Denmark)

    Monshupanee, Tanakarn; Gregory, Steven T; Douthwaite, Stephen; Chungjatupornchai, Wipa; Dahlberg, Albert E

    2008-01-01

    Translocation during the elongation phase of protein synthesis involves the relative movement of the 30S and 50S ribosomal subunits. This movement is the target of tuberactinomycin antibiotics. Here, we describe the isolation and characterization of mutants of Thermus thermophilus selected for...

  12. Effect of bifidobacterium Bb12 with or without Streptococcus thermophilus supplemented formula on nutritional status.

    Science.gov (United States)

    Nopchinda, Supujchara; Varavithya, Wandee; Phuapradit, Pornpimol; Sangchai, Rawiwan; Suthutvoravut, Umaporn; Chantraruksa, Vinita; Haschke, Ferdinand

    2002-11-01

    Acute diarrhea is a common cause of infant morbidity and mortality. Probiotic supplemented infant formula is one of the effective methods for prevention of rotavirus diarrhea. Other benefits of the probiotics supplemented formula were evaluated by monitoring the growth of the children. A double-blind, placebo-controlled trial was done in 148 children aged 6-36 months. They were divided into 3 groups: the Bb12 group, 51 children received infant formula with Bifidobacteria Bb12 supplement; the Bb12+ST group, 54 children received infant formula with Bb12 and Streptococcus thermophilus supplement; and the control group, 43 children received infant formula without supplement. The mean weight Z-score according to WHO reference standard of the Bbl2 group was -1.8 +/- 0.12, the Bb12+ST group was -1.4 +/- 0.11 and the control group was -1.8 +/- 0.13 at entry. The mean weight Z-score of children after 6 month showed that the children in the Bbl2+ST group had the highest increase in weight which was increased from -1.4 +/- 0.11 to -0.9 +/- 0.12 compared to the Z-score of the Bb12 group which had increased from -1.8 +/- 0.12 to -1.2 +/- 0.13 and in the control group from -1.8 +/- 0.13 to -1.7 +/- 0.25. In terms of the mean height Z-score, the Bb12 group was -2.7 +/- 0.14 to -1.7 +/- 0.16 which was higher than the Bb12+ST group (- 2.2 +/- 0.13 to -1.7 +/- 0.13) but was not different from the control group. However, the mean weight/height Z-score of the Bbl2+ST group had approached the reference standard (Bb12 group -0.1 +/- 0.11 to -0.1 +/- 0.13, Bb12+ST group -0.1 +/- 0.10 to 0.3 +/- 0.17, control group -0.4 +/- 0.12 to -0.1 +/- 0.16). Data showed that children who received the probiotics supplement formula had better growth during the 6 month period. PMID:12549799

  13. Impact of engineered Streptococcus thermophilus trains overexpressing glyA gene on folic acid and acetaldehyde production in fermented milk Impacto de linhagens de Streptococcus thermophilus com aumento da expressão do gene glyA na produção de ácido folico e acetaldeído em leite fermentado

    Directory of Open Access Journals (Sweden)

    Ana Carolina Sampaio Dória Chaves

    2003-11-01

    Full Text Available The typical yogurt flavor is caused by acetaldehyde produced through many different pathways by the yogurt starter bacteria L. bulgaricus and S. thermophilus. The attention was focused on one specific reaction for acetaldehyde and folic acid formation catalyzed by serine hydroxymethyltransferase (SHMT, encoded by the glyA gene. In S. thermophilus, this enzyme SHMT also plays the typical role of the enzyme threonine aldolase (TA that is the interconvertion of threonine into glycine and acetaldehyde. The behavior of engineered S. thermophilus strains in milk fermentation is described, folic acid and acetaldehyde production were measured and pH and counts were followed. The engineered S. thermophilus strains StA2305 and StB2305, have the glyA gene (encoding the enzyme serine hydroxymethyltransferase overexpressed. These engineered strains showed normal growth in milk when it was supplemented with Casitione. When they were used in milk fermentation it was observed an increase in folic acid and in acetaldehyde production by StA2305 and for StB2305 it was noticed a significative increase in folic acid formation.O acetaldeído, responsável pelo sabor e aroma característicos de iogurte, é produzido por diferentes vias metabólicas pelas bactérias lácticas: Streptococcus thermophilus (S. thermophilus e Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus. Neste trabalho, a atenção foi focada especificamente na reação para a formação de acetaldeído e de ácido fólico, catalisada pela enzima serina hidroximetil transferase (SHMT, codificada pelo gene glyA. A enzima SHMT catalisa diversas reações e, no caso da bactéria S. thermophilus, ela exerce também a atividade característica da enzima treonina aldolase (TA, definida como a interconversão do aminoácido treonina em glicina e acetaldeído. Foram construídas linhagens de S. thermophilus (StA2305 e StB2305 com super expressão do gene glyA. Estas linhagens modificadas apresentaram

  14. Electron transfer among the CuA-, heme b- and a3-centers of Thermus thermophilus cytochrome ba3

    DEFF Research Database (Denmark)

    Farver, Ole; Chen, Ying; Fee, James A;

    2006-01-01

    The 1-methyl-nicotinamide radical (MNA(*)), produced by pulse radiolysis has previously been shown to reduce the Cu(A)-site of cytochromes aa(3), a process followed by intramolecular electron transfer (ET) to the heme a but not to the heme a(3) [Farver, O., Grell, E., Ludwig, B., Michel, H. and...... Pecht, I. (2006) Rates and equilibrium of CuA to heme a electron transfer in Paracoccus denitrificans cytochrome c oxidase. Biophys. J. 90, 2131-2137]. Investigating this process in the cytochrome ba(3) of Thermus thermophilus (Tt), we now show that MNA(*) also reduces Cu(A) with a subsequent ET to the...... heme b and then to heme a(3), with first-order rate constants 11200 s(-1), and 770 s(-1), respectively. The results provide clear evidence for ET among the three spectroscopically distinguishable centers and indicate that the binuclear a(3)-Cu(B) center can be reduced in molecules containing a single...

  15. Complete genome sequence of Streptococcus thermophilus MN-BM-A01, a strain with high exopolysaccharides production.

    Science.gov (United States)

    Bai, Ying; Sun, Erna; Shi, Yudong; Jiang, Yunyun; Chen, Yun; Liu, Songling; Zhao, Liang; Zhang, Ming; Guo, Huiyuan; Zhang, Hao; Mu, Zhishen; Ren, Fazheng

    2016-04-20

    Streptococcus thermophilus MN-BM-A01 (ST MN-BM-A01) (CGMCC No. 11383) was a strain isolated from Yogurt Block in Gansu, China. The yogurt fermented with this strain has good flavor, acidity, and viscosity. Moreover, ST MN-BM-A01 could produce a high level of EPS which can confer the yogurt with improved rheological properties. We reported the complete genome sequence of ST MN-BM-A01 that contains 1,876,516bp encoding 1704 coding sequences (CDSs), 67 tRNA genes and 6 rRNA operons. The genomic sequence indicated that this strain included a 35.3-kb gene cluster involved in EPS biosynthesis. PMID:26956372

  16. Nutritional Composition and Protein Profile of Goat Yogurt PE with Double Culture between Streptococcus thermophilus and Lactobacilus species

    Directory of Open Access Journals (Sweden)

    Ismi Kurnia Budiarti

    2013-08-01

    Full Text Available Aim: The aims of this study are to characterize the nutrient compositions and protein profiles of Etawah breed (PE goat yogurt fermented by double cultures . Material and Methods: To accomplish this, we used goat and bovine milk in five treatment groups: (1 fresh milk bovine, (2 goat,(3 milk fermented by L. acidophilus and S. thermophilus (LA + ST, (4 L. bulgaricus and S. thermophilus (LB+ ST,and (5 a comersial mixture. PE goat milk was fermented using 2.5% starting bacterial concentrations at 45oC with a pH ranging from 4.5 to 6.6. Nutrient compositions were measured by proximate analysis.SDS PAGE was conducted using 15% separating and 3% stacking gels. To measure the density of protein bands, we used QuantityOne software. Results: Our results indicated that LA+ST and LB+ST treatments had higher levels of lipids than the control treatment. Conversely, both strain combinations had lower levels of proteins than the control. Organoleptic testing suggests that many attributes (e.g., colour, taste, smell, texture and viscosity differ significantly from the control. Protein profiles revealed that while the LB + ST and commercial cultures contained proteins with a molecular weight of 36 kDa, the LA + ST cultures did not appear to possess this protein.Based on the molecular weight, we suggest that this protein is in the alpha casein group. Conclusion: The protein composition of fermented goat and bovine milk is similiar, but the absence of band with molecular weight 36 kDa from goat milk, LB+ST and mix comercial. [Cukurova Med J 2013; 38(4.000: 681-686

  17. The extent of co-metabolism of glucose and galactose by L. lactis changes with the expression of the lacSZ operon from Streptococcus thermophilus

    DEFF Research Database (Denmark)

    Solem, Christian; Købmann, Brian Jensen; Jensen, Peter Ruhdal

    2008-01-01

    The lactose transporter and β-galactosidase from Streptococcus thermophilus, encoded by the lacSZ operon, were introduced into the lactose-negative strain Lactococcus lactis MG1363 and the expression of the lacSZ operon was modulated by substitution of the native promoter with randomized synthetic...... only glucose was metabolized in glycolysis. Interestingly, strains with low expression of the operon showed a mixed acid metabolism and co-metabolism of galactose and glucose. The lactose flux increased gradually with increasing expression of the lacSZ operon until an optimum was observed at...... promoters. A series of strains with various expression levels of lacSZ were examined for their fermentation of lactose. Strains with a high expression level were found to metabolize lactose in a similar manner to S. thermophilus, i.e. the galactose moiety of lactose was excreted to the growth medium and...

  18. beta-Glucosidase as a reporter for the gene expression studies in Thermus thermophilus and constitutive expression of DNA repair genes.

    Science.gov (United States)

    Ohta, Toshihiro; Tokishita, Shin-Ichi; Imazuka, Reiko; Mori, Ichiro; Okamura, Jin; Yamagata, Hideo

    2006-07-01

    Thermus thermophilus is an extremely thermophilic eubacterium that grows optimally at 70-75 degrees C. Because the frequency of DNA damage, such as deamination, depurination and single-strand breaks, increases as the temperature rises, the regulation of expression as well as the specificities and activities of T.thermophilus DNA repair systems are of particular interest. To study those systems, we developed a gene expression vector using the T.thermophilus beta-glucosidase gene (bgl) with host strain JOS9 (Deltabgl) derived from the T.thermophilus wild-type strain HB27. Since HB27 has two putative beta-galactosidase genes, the use of a single bgl gene as a reporter in combination with a Deltabgl host strain permits the study of gene expression against a low background level. We assayed Bgl activity with 2-nitrophenyl-beta-d-glucopyranoside as the substrate at 80 degrees C. We measured the expression of seven genes involved in DNA repair--three nucleotide excision repair genes (uvrA, uvrB and uvrC) and four recombinational repair genes (recA, ruvA, ruvB and ruvC). Expression levels of uvrA and uvrB were about three times those of uvrC, while those of ruvA, ruvB and ruvC were almost equal. Both ruvA and ruvC formed an operon with their adjacent 5'-upstream gene paaG and ftsQAZ, respectively. recA was transcribed as an operon of four genes, amt-cinA-ligT-recA. All seven DNA repair genes were expressed constitutively, and the DNA damaging agent mitomycin C did not increase their expression. PMID:16777922

  19. Selective and differential enumerations of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium spp. in yoghurt--a review.

    Science.gov (United States)

    Ashraf, Rabia; Shah, Nagendra P

    2011-10-01

    Yoghurt is increasingly being used as a carrier of probiotic bacteria for their potential health benefits. To meet with a recommended level of ≥10(6) viable cells/g of a product, assessment of viability of probiotic bacteria in market preparations is crucial. This requires a working method for selective enumeration of these probiotic bacteria and lactic acid bacteria in yoghurt such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lb. acidophilus, Lb. casei and Bifidobacterium. This chapter presents an overview of media that could be used for differential and selective enumerations of yoghurt bacteria. De Man Rogosa Sharpe agar containing fructose (MRSF), MRS agar pH 5.2 (MRS 5.2), reinforced clostridial prussian blue agar at pH 5.0 (RCPB 5.0) or reinforced clostridial agar at pH 5.3 (RCA 5.3) are suitable for enumeration of Lb. delbrueckii subsp. bulgaricus when the incubation is carried out at 45°C for 72h. S. thermophilus (ST) agar and M17 are recommended for selective enumeration of S. thermophilus. Selective enumeration of Lb. acidophilus in mixed culture could be made in Rogosa agar added with 5-bromo-4-chloro-3-indolyl-β-d-glucopyranoside (X-Glu) or MRS containing maltose (MRSM) and incubation in a 20% CO2 atmosphere. Lb. casei could be selectively enumerated on specially formulated Lb. casei (LC) agar from products containing yoghurt starter bacteria (S. thermophilus and Lb. delbrueckii subsp. bulgaricus), Lb. acidophilus, Bifidobacterium spp. and Lb. casei. Bifidobacterium could be enumerated on MRS agar supplemented with nalidixic acid, paromomycin, neomycin sulphate and lithium chloride (MRS-NPNL) under anaerobic incubation at 37°C for 72h. PMID:21807435

  20. The Activity of the Lactose Transporter from Streptococcus thermophilus Is Increased by Phosphorylated IIA and the Action of β-Galactosidase

    OpenAIRE

    Geertsma, Eric R.; Duurkens, Ria H.; Poolman, Bert

    2005-01-01

    The metabolism of lactose by Streptococcus thermophilus is highly regulated, allowing the bacterium to prefer lactose over glucose as main source of carbon and energy. In vitro analysis of the enzymes involved in transport and hydrolysis of lactose showed that the transport reaction benefits from the hydrolysis of lactose at the trans side of the membrane. Furthermore, the activity of LacS is modulated by PEP-dependent phosphorylation of the IIA domain via the general energy coupling proteins...

  1. Structural Analysis of Thermus thermophilus HB27 Mannosyl-3-phosphoglycerate Synthase Provides Evidence for a Second Catalytic Metal Ion and New Insight into the Retaining Mechanism of Glycosyltransferases

    OpenAIRE

    Gonçalves, Susana; Borges, Nuno; Esteves, Ana M.; Bruno L. Victor; Soares, Cláudio M.; Santos, Helena; Matias, Pedro M.

    2010-01-01

    Mannosyl-3-phosphoglycerate synthase is a glycosyltransferase involved in the two-step synthetic pathway of mannosylglycerate, a compatible solute that accumulates in response to salt and/or heat stresses in many microorganisms thriving in hot environments. The three-dimensional structure of mannosyl-3-phosphoglycerate synthase from Thermus thermophilus HB27 in its binary complex form, with GDP-α-d-mannose and Mg2+, shows a second metal binding site, about 6 Å away from the mannose moiety. Ki...

  2. Co-utilization of glucose and xylose by evolved Thermus thermophilus LC113 strain elucidated by (13)C metabolic flux analysis and whole genome sequencing.

    Science.gov (United States)

    Cordova, Lauren T; Lu, Jing; Cipolla, Robert M; Sandoval, Nicholas R; Long, Christopher P; Antoniewicz, Maciek R

    2016-09-01

    We evolved Thermus thermophilus to efficiently co-utilize glucose and xylose, the two most abundant sugars in lignocellulosic biomass, at high temperatures without carbon catabolite repression. To generate the strain, T. thermophilus HB8 was first evolved on glucose to improve its growth characteristics, followed by evolution on xylose. The resulting strain, T. thermophilus LC113, was characterized in growth studies, by whole genome sequencing, and (13)C-metabolic flux analysis ((13)C-MFA) with [1,6-(13)C]glucose, [5-(13)C]xylose, and [1,6-(13)C]glucose+[5-(13)C]xylose as isotopic tracers. Compared to the starting strain, the evolved strain had an increased growth rate (~2-fold), increased biomass yield, increased tolerance to high temperatures up to 90°C, and gained the ability to grow on xylose in minimal medium. At the optimal growth temperature of 81°C, the maximum growth rate on glucose and xylose was 0.44 and 0.46h(-1), respectively. In medium containing glucose and xylose the strain efficiently co-utilized the two sugars. (13)C-MFA results provided insights into the metabolism of T. thermophilus LC113 that allows efficient co-utilization of glucose and xylose. Specifically, (13)C-MFA revealed that metabolic fluxes in the upper part of metabolism adjust flexibly to sugar availability, while fluxes in the lower part of metabolism remain relatively constant. Whole genome sequence analysis revealed two large structural changes that can help explain the physiology of the evolved strain: a duplication of a chromosome region that contains many sugar transporters, and a 5x multiplication of a region on the pVV8 plasmid that contains xylose isomerase and xylulokinase genes, the first two enzymes of xylose catabolism. Taken together, (13)C-MFA and genome sequence analysis provided complementary insights into the physiology of the evolved strain. PMID:27164561

  3. 2-Methylthio-1,4-naphthoquinone, a unique sulfur-containing quinone from a thermophilic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus.

    OpenAIRE

    Ishii, M.; Kawasumi, T.; Igarashi, Y.; Kodama, T; Minoda, Y

    1987-01-01

    A quinone was extracted and purified from the cells of an extremely thermophilic hydrogen bacterium, Hydrogenobacter thermophilus TK-6 (IAM 12695). Its chemical structure was determined as 2-methylthio-3-VI, VII-tetrahydromultiprenyl-1,4-naphthoquinone by elemental analysis, 1H nuclear magnetic resonance spectroscopy, mass spectroscopy, and infrared spectroscopy of the quinone and by gas-liquid chromatography and gas chromatography-mass spectroscopy analysis of the ozonolysis products of the ...

  4. High yield of mannosylglycerate production by upshock fermentation and bacterial milking of trehalose-deficient mutant Thermus thermophilus RQ-1.

    Science.gov (United States)

    Egorova, K; Grudieva, T; Morinez, C; Kube, J; Santos, H; da Costa, M S; Antranikian, G

    2007-07-01

    A production process, using upshock fermentation and osmotic downshock, for the effective production/excretion of mannosylglycerate (MG) by the trehalose-deficient mutant of the strain Thermus thermophilus RQ-1 has been developed. In the first phase of fed-batch fermentation, the knockout mutant was grown at 70 degrees C on a NaCl-free medium. After the culture reached the end of the exponential growth phase, upshift in temperature and NaCl concentration was applied. The temperature was increased to 77 degrees C, and NaCl was added up to 3.0% and kept constant during the second phase of fermentation. Although this shift in cultivation parameters caused a dramatic drop of cell density, a significant improvement in accumulation of MG up to 0.64 micromol/mg protein compared to batch fermentations (0.31 micromol/mg protein) was achieved. A total yield of 4.6 g MG/l of fermentation broth was obtained in the dialysis bioreactor with a productivity of 0.29 g MG l(-1) h(-1). The solute was released from the harvested biomass by osmotic downshock using demineralized water at 70 degrees C. More than 90% of the intracellularly accumulated solute was recovered from the water fraction. The process was very efficient, as hyperosmotic shock, release of the solute, and reiterative fed-batch fermentation could be repeated at least four times. PMID:17361428

  5. A novel heme a insertion factor gene cotranscribes with the Thermus thermophilus cytochrome ba3 oxidase locus.

    Science.gov (United States)

    Werner, Carolin; Richter, Oliver-Matthias H; Ludwig, Bernd

    2010-09-01

    Studying the biogenesis of the Thermus thermophilus cytochrome ba(3) oxidase, we analyze heme a cofactor insertion into this membrane protein complex. Only three proteins linked to oxidase maturation have been described for this extreme thermophile, and in particular, no evidence for a canonical Surf1 homologue, required for heme a insertion, is available from genome sequence data. Here, we characterize the product of an open reading frame, cbaX, in the operon encoding subunits of the ba(3)-type cytochrome c oxidase. CbaX shares no sequence identity with any known oxidase biogenesis factor, and CbaX homologues are found only in the Thermaceae group. In a series of cbaX deletion and complementation experiments, we demonstrate that the resulting ba(3) oxidase complexes, affinity purified via an internally inserted His tag located in subunit I, are severely affected in their enzymatic activities and heme compositions in both the low- and high-spin sites. Thus, CbaX displays typical features of a generic Surf1 factor essential for binding and positioning the heme a moiety for correct assembly into the protein scaffold of oxidase subunit I. PMID:20622059

  6. Probiotic Leuconostoc mesenteroides ssp.cremoris and Streptococcus thermophilus induce IL-12 and IFN-γ production

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM: To investigate the capacity of potentially probiotic strains from six bacterial genera to induce cytokine production alone or in combinations in order to identify potential enhancing or synergistic effects in order to select probiotic bacteria for in vivo purposes. METHODS: Cytokine production in human peripheral blood mononuclear cells (PBMC) in response to stimulation with eleven different potentially probiotic bacterial strains from Streptococcus, Lactobacillus, Bifidobacterium, Lactococcus, Leuconostoc and Propionibacterium genera was analysed. Production and mRNA expression of TNF-α, IL-12,IFN-γ and IL-10 were determined by ELISA and Northern blotting, respectively. RESULTS: All tested bacteria induced TNF-α production. The best inducers of Thl type cytokines IL-12 and IFN-γ were Streptococcus and Leuconostoc strains. All Bifidobacteriurn and Propionibacteriurn strains induced higher IL-10 production than other studied bacteria. Stimulation of PBNC with any bacterial combinations did not result in enhanced cytokine production suggesting that different bacteria whether gram-positive or gram negative compete with each other during host cell interactions. CONCLUSION: The probiotic S. thermophilus and Leuconostoc strains are more potent inducers of Thl type cytokines IL-12 and IFN-γ than the probiotic Lactobacillus strains. Bacterial combinations did not result in enhanced cytokine production.

  7. Characterization, Anti-Inflammatory and Antiproliferative Activities of Natural and Sulfonated Exo-Polysaccharides from Streptococcus thermophilus ASCC 1275.

    Science.gov (United States)

    Li, Siqian; Shah, Nagendra P

    2016-05-01

    Exo-polysaccharides (EPS) isolated from Streptococcus thermophilus ASCC 1275 were sulfated (31%). High-performance liquid chromatography identified that EPS was composed of mannose (30.19%), galactose (20.10%), glucose (18.05%), glucosamine (16.04%), galactosamine (9.06%), glucuronic acid (3.55%), and ribose (3.01%). Pro-/anti-inflammatory cytokine secretion ratios (IL-1β/IL-10, IL-6/IL-10, and TNF-α/IL-10) of lipopolysaccharide stimulated RAW 264.7 macrophages were significantly decreased by EPS and S.EPS treatments in a dose dependent manner. Furthermore, anti-inflammatory activities of S.EPS improved 49.3% and 24.0% than those of EPS before or after LPS treatment. The reactive oxygen species were inhibited by EPS and S.EPS by 49.6% and 55.1% at 50 μg/mL, respectively. Inhibition activities of S.EPS on nitric oxide production were 12.9% and 55.4% higher than those of EPS at 10 and 50 μg/mL. Additionally, S.EPS exhibited stronger antiproliferative activity on Caco-2 and HepG2 cells. Our results indicated that anti-inflammatory and antiproliferative activities of EPS were significantly (P < 0.01) improved by sulfonation. PMID:27010963

  8. 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

    Science.gov (United States)

    Vaillancourt, Katy; Moineau, Sylvain; Frenette, Michel; Lessard, Christian; Vadeboncoeur, Christian

    2002-01-01

    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. PMID:11790749

  9. Quantitative analysis of the lactic acid and acetaldehyde produced by Streptococcus thermophilus and Lactobacillus bulgaricus strains isolated from traditional Turkish yogurts using HPLC.

    Science.gov (United States)

    Gezginc, Y; Topcal, F; Comertpay, S; Akyol, I

    2015-03-01

    The present study was conducted to evaluate the lactic acid- and acetaldehyde-producing abilities of lactic acid bacterial species isolated from traditionally manufactured Turkish yogurts using HPLC. The lactic acid bacterial species purified from the yogurts were the 2 most widely used species in industrial yogurt production: Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria have the ability to ferment hexose sugars homofermentatively to generate lactic acid and some carbonyl compounds, such as acetaldehyde through pyruvate metabolism. The levels of the compounds produced during fermentation influence the texture and the flavor of the yogurt and are themselves influenced by the chemical composition of the milk, processing conditions, and the metabolic activity of the starter culture. In the study, morphological, biochemical, and molecular characteristics were employed to identify the bacteria obtained from homemade yogurts produced in different regions of Turkey. A collection of 91 Strep. thermophilus and 35 L. bulgaricus strains were investigated for their lactic acid- and acetaldehyde-formation capabilities in various media such as cow milk, LM17 agar, and aerobic-anaerobic SM17 agar or de Man, Rogosa, and Sharpe agar. The amounts of the metabolites generated by each strain in all conditions were quantified by HPLC. The levels were found to vary depending on the species, the strain, and the growth conditions used. Whereas lactic acid production ranged between 0 and 77.9 mg/kg for Strep. thermophilus strains, it ranged from 0 to 103.5 mg/kg for L. bulgaricus. Correspondingly, the ability to generate acetaldehyde ranged from 0 to 105.9 mg/kg in Strep. thermophilus and from 0 to 126.9 mg/kg in L. bulgaricus. Our study constitutes the first attempt to determine characteristics of the wild strains isolated from traditional Turkish yogurts, and the approach presented here, which reveals the differences in metabolite production abilities of the

  10. Molecular identification of differentially regulated genes in the hydrothermal-vent species Bathymodiolus thermophilus and Paralvinella pandorae in response to temperature

    Directory of Open Access Journals (Sweden)

    Shillito Bruce

    2009-05-01

    Full Text Available Abstract Background Hydrothermal vents and cold seeps represent oases of life in the deep-sea environment, but are also characterized by challenging physical and chemical conditions. The effect of temperature fluctuations on vent organisms in their habitat has not been well explored, in particular at a molecular level, most gene expression studies being conducted on coastal marine species. In order to better understand the response of hydrothermal organisms to different temperature regimes, differentially expressed genes (obtained by a subtractive suppression hybridization approach were identified in the mussel Bathymodiolus thermophilus and the annelid Paralvinella pandorae irlandei to characterize the physiological processes involved when animals are subjected to long term exposure (2 days at two contrasting temperatures (10° versus 20°C, while maintained at in situ pressures. To avoid a potential effect of pressure, the experimental animals were initially thermally acclimated for 24 hours in a pressurized vessel. Results For each species, we produced two subtractive cDNA libraries (forward and reverse from sets of deep-sea mussels and annelids exposed together to a thermal challenge under pressure. RNA extracted from the gills, adductor muscle, mantle and foot tissue were used for B. thermophilus. For the annelid model, whole animals (small individuals were used. For each of the four libraries, we sequenced 200 clones, resulting in 78 and 83 unique sequences in mussels and annelids (about 20% of the sequencing effort, respectively, with only half of them corresponding to known genes. Real-time PCR was used to validate differentially expressed genes identified in the corresponding libraries. Strong expression variations have been observed for some specific genes such as the intracellular hemoglobin, the nidogen protein, and Rab7 in P. pandorae, and the SPARC protein, cyclophilin, foot protein and adhesive plaque protein in B. thermophilus

  11. Use of microparticulated whey protein concentrate, exopolysaccharide-producing Streptococcus thermophilus, and adjunct cultures for making low-fat Italian Caciotta-type cheese

    OpenAIRE

    Di Cagno, R.; De Pasquale, I.; De Angelis, M.; Buchin, Solange; Rizzello, C. G.; Gobbetti, M

    2014-01-01

    Low-fat Caciotta-type cheeses were manufactured with partially skim milk (fat content of similar to 0.3%) alone (LFC); with the supplementation of 0.5% (wt/vol) microparticulated whey protein concentrate (MWPC) (LFC-MWPC); with MWPC and exopolysaccharides (EPS)-producing Streptococcus thermophilus ST446 (LFC-MWPC-EPS); and with MWPC, EPS-producing strain ST446, and Lactobacillus plantarum LP and Lactobacillus rhamnosus LRA as adjunct cultures (LFC-MWPC-EPS-A). The non-EPS-producing isogenic v...

  12. Improved acid stress survival of Lactococcus lactis expressing the histidine decarboxylation pathway of Streptococcus thermophilus CHCC1524.

    Science.gov (United States)

    Trip, Hein; Mulder, Niels L; Lolkema, Juke S

    2012-03-30

    Degradative amino acid decarboxylation pathways in bacteria generate secondary metabolic energy and provide resistance against acid stress. The histidine decarboxylation pathway of Streptococcus thermophilus CHCC1524 was functionally expressed in the heterologous host Lactococcus lactis NZ9000, and the benefits of the newly acquired pathway for the host were analyzed. During growth in M17 medium in the pH range of 5-6.5, a small positive effect was observed on the biomass yield in batch culture, whereas no growth rate enhancement was evident. In contrast, a strong benefit for the engineered L. lactis strain was observed in acid stress survival. In the presence of histidine, the pathway enabled cells to survive at pH values as low as 3 for at least 2 h, conditions under which the host cells were rapidly dying. The flux through the histidine decarboxylation pathway in cells grown at physiological pH was under strict control of the electrochemical proton gradient (pmf) across the membrane. Ionophores that dissipated the membrane potential (ΔΨ) and/or the pH gradient (ΔpH) strongly increased the flux, whereas the presence of glucose almost completely inhibited the flux. Control of the pmf over the flux was exerted by both ΔΨ and ΔpH and was distributed over the transporter HdcP and the decarboxylase HdcA. The control allowed for a synergistic effect between the histidine decarboxylation and glycolytic pathways in acid stress survival. In a narrow pH range around 2.5 the synergism resulted in a 10-fold higher survival rate. PMID:22351775

  13. Phosphoproteomic analysis reveals the effects of PilF phosphorylation on type IV pilus and biofilm formation in Thermus thermophilus HB27.

    Science.gov (United States)

    Wu, Wan-Ling; Liao, Jiahn-Haur; Lin, Guang-Huey; Lin, Miao-Hsia; Chang, Ying-Che; Liang, Suh-Yuen; Yang, Feng-Ling; Khoo, Kay-Hooi; Wu, Shih-Hsiung

    2013-10-01

    Thermus thermophilus HB27 is an extremely thermophilic eubacteria with a high frequency of natural competence. This organism is therefore often used as a thermophilic model to investigate the molecular basis of type IV pili-mediated functions, such as the uptake of free DNA, adhesion, twitching motility, and biofilm formation, in hot environments. In this study, the phosphoproteome of T. thermophilus HB27 was analyzed via a shotgun approach and high-accuracy mass spectrometry. Ninety-three unique phosphopeptides, including 67 in vivo phosphorylated sites on 53 phosphoproteins, were identified. The distribution of Ser/Thr/Tyr phosphorylation sites was 57%/36%/7%. The phosphoproteins were mostly involved in central metabolic pathways and protein/cell envelope biosynthesis. According to this analysis, the ATPase motor PilF, a type IV pili-related component, was first found to be phosphorylated on Thr-368 and Ser-372. Through the point mutation of PilF, mimic phosphorylated mutants T368D and S372E resulted in nonpiliated and nontwitching phenotypes, whereas nonphosphorylated mutants T368V and S372A displayed piliation and twitching motility. In addition, mimic phosphorylated mutants showed elevated biofilm-forming abilities with a higher initial attachment rate, caused by increasing exopolysaccharide production. In summary, the phosphorylation of PilF might regulate the pili and biofilm formation associated with exopolysaccharide production. PMID:23828892

  14. A highly conserved DNA replication module from Streptococcus thermophilus phages is similar in sequence and topology to a module from Lactococcus lactis phages.

    Science.gov (United States)

    Desiere, F; Lucchini, S; Bruttin, A; Zwahlen, M C; Brüssow, H

    1997-08-01

    A highly conserved DNA region extending over 5 kb was observed in Streptococcus thermophilus bacteriophages. Comparative sequencing of one temperate and 26 virulent phages demonstrated in the most extreme case an 18% aa difference for a predicted protein, while the majority of the phages showed fewer, if any aa changes. The relative degree of aa conservation was not homogeneous over the DNA segment investigated. Sequence analysis of the conserved segment revealed genes possibly involved in DNA transactions. Three predicted proteins (orf 233, 443, and 382 gene product (gp)) showed nucleoside triphosphate binding motifs. Orf 443 gp showed in addition a DEAH box motif, characteristically found in a subgroup of helicases, and a variant zinc finger motif known from a phage T7 helicase/primase. Tree analysis classified orf 443 gp as a distant member of the helicase superfamily. Orf 382 gp showed similarity to putative plasmid DNA primases. Downstream of orf 382 a noncoding repeat region was identified that showed similarity to a putative minus origin from a cryptic S. thermophilus plasmid. Four predicted proteins showed not only high degrees of aa identity (34 to 63%) with proteins from Lactococcus lactis phages, but their genes showed a similar topological organization. We interpret this as evidence for a horizontal gene transfer event between phages of the two bacterial genera in the distant past. PMID:9268169

  15. Purification, crystallization and preliminary X-ray diffraction of SecDF, a translocon-associated membrane protein, from Thermus thermophilus

    International Nuclear Information System (INIS)

    SecDF is a multi-path membrane protein required for efficient protein translocation and integration via translocon. Purification and crystallization of T. thermophilus SecDF have been achieved by exploiting unique crystallization techniques that allowed the collection of a 3.74 Å data set. Thermus thermophilus has a multi-path membrane protein, TSecDF, as a single-chain homologue of Escherichia coli SecD and SecF, which form a translocon-associated complex required for efficient preprotein translocation and membrane-protein integration. Here, the cloning, expression in E. coli, purification and crystallization of TSecDF are reported. Overproduced TSecDF was solubilized with dodecylmaltoside, chromatographically purified and crystallized by vapour diffusion in the presence of polyethylene glycol. The crystals yielded a maximum resolution of 4.2 Å upon X-ray irradiation, revealing that they belonged to space group P43212. Attempts were made to improve the diffraction quality of the crystals by combinations of micro-stirring, laser-light irradiation and dehydration, which led to the eventual collection of complete data sets at 3.74 Å resolution and preliminary success in the single-wavelength anomalous dispersion analysis. These results provide information that is essential for the determination of the three-dimensional structure of this important membrane component of the protein-translocation machinery

  16. Models for the a subunits of the Thermus thermophilus V/A-ATPase and Saccharomyces cerevisiae V-ATPase enzymes by cryo-EM and evolutionary covariance.

    Science.gov (United States)

    Schep, Daniel G; Zhao, Jianhua; Rubinstein, John L

    2016-03-22

    Rotary ATPases couple ATP synthesis or hydrolysis to proton translocation across a membrane. However, understanding proton translocation has been hampered by a lack of structural information for the membrane-embedded a subunit. The V/A-ATPase from the eubacteriumThermus thermophilusis similar in structure to the eukaryotic V-ATPase but has a simpler subunit composition and functions in vivo to synthesize ATP rather than pump protons. We determined theT. thermophilusV/A-ATPase structure by cryo-EM at 6.4 Å resolution. Evolutionary covariance analysis allowed tracing of the a subunit sequence within the map, providing a complete model of the rotary ATPase. Comparing the membrane-embedded regions of theT. thermophilusV/A-ATPase and eukaryotic V-ATPase fromSaccharomyces cerevisiaeallowed identification of the α-helices that belong to the a subunit and revealed the existence of previously unknown subunits in the eukaryotic enzyme. Subsequent evolutionary covariance analysis enabled construction of a model of the a subunit in theS. cerevisaeV-ATPase that explains numerous biochemical studies of that enzyme. Comparing the two a subunit structures determined here with a structure of the distantly related a subunit from the bovine F-type ATP synthase revealed a conserved pattern of residues, suggesting a common mechanism for proton transport in all rotary ATPases. PMID:26951669

  17. Purification, crystallization and preliminary X-ray diffraction of SecDF, a translocon-associated membrane protein, from Thermus thermophilus

    Energy Technology Data Exchange (ETDEWEB)

    Tsukazaki, Tomoya; Mori, Hiroyuki [Institute for Virus Research, Kyoto University, Kyoto 606-8507 (Japan); Fukai, Shuya; Numata, Tomoyuki [Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa 226-8501 (Japan); Perederina, Anna [Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Schools of Medicine and Dentistry, Birmingham, Alabama 35294 (United States); Adachi, Hiroaki [SOSHO Inc., 7-7-15-208 Asagi, Saito, Ibaraki, Osaka 567-0085 (Japan); Department of Electrical, Electronic and Information Engineering, Osaka University, Osaka 565-0871 (Japan); CREST, JST, Saitama 332-0012 (Japan); Matsumura, Hiroyoshi [SOSHO Inc., 7-7-15-208 Asagi, Saito, Ibaraki, Osaka 567-0085 (Japan); CREST, JST, Saitama 332-0012 (Japan); Department of Materials Chemistry, Osaka University, Osaka 565-0871 (Japan); Takano, Kazufumi [SOSHO Inc., 7-7-15-208 Asagi, Saito, Ibaraki, Osaka 567-0085 (Japan); CREST, JST, Saitama 332-0012 (Japan); Department of Material and Life Science, Osaka University, Osaka 565-0871 (Japan); Murakami, Satoshi [SOSHO Inc., 7-7-15-208 Asagi, Saito, Ibaraki, Osaka 567-0085 (Japan); CREST, JST, Saitama 332-0012 (Japan); PRESTO, JST, Saitama 332-0012 (Japan); Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047 (Japan); Inoue, Tsuyoshi [SOSHO Inc., 7-7-15-208 Asagi, Saito, Ibaraki, Osaka 567-0085 (Japan); CREST, JST, Saitama 332-0012 (Japan); Department of Materials Chemistry, Osaka University, Osaka 565-0871 (Japan); Mori, Yusuke; Sasaki, Takatomo [SOSHO Inc., 7-7-15-208 Asagi, Saito, Ibaraki, Osaka 567-0085 (Japan); Department of Electrical, Electronic and Information Engineering, Osaka University, Osaka 565-0871 (Japan); CREST, JST, Saitama 332-0012 (Japan); Vassylyev, Dmitry G. [Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Schools of Medicine and Dentistry, Birmingham, Alabama 35294 (United States); Nureki, Osamu, E-mail: onureki@bio.titech.ac.jp [Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa 226-8501 (Japan); PRESTO, JST, Saitama 332-0012 (Japan); Ito, Koreaki, E-mail: onureki@bio.titech.ac.jp [Institute for Virus Research, Kyoto University, Kyoto 606-8507 (Japan); CREST, JST, Saitama 332-0012 (Japan)

    2006-04-01

    SecDF is a multi-path membrane protein required for efficient protein translocation and integration via translocon. Purification and crystallization of T. thermophilus SecDF have been achieved by exploiting unique crystallization techniques that allowed the collection of a 3.74 Å data set. Thermus thermophilus has a multi-path membrane protein, TSecDF, as a single-chain homologue of Escherichia coli SecD and SecF, which form a translocon-associated complex required for efficient preprotein translocation and membrane-protein integration. Here, the cloning, expression in E. coli, purification and crystallization of TSecDF are reported. Overproduced TSecDF was solubilized with dodecylmaltoside, chromatographically purified and crystallized by vapour diffusion in the presence of polyethylene glycol. The crystals yielded a maximum resolution of 4.2 Å upon X-ray irradiation, revealing that they belonged to space group P4{sub 3}2{sub 1}2. Attempts were made to improve the diffraction quality of the crystals by combinations of micro-stirring, laser-light irradiation and dehydration, which led to the eventual collection of complete data sets at 3.74 Å resolution and preliminary success in the single-wavelength anomalous dispersion analysis. These results provide information that is essential for the determination of the three-dimensional structure of this important membrane component of the protein-translocation machinery.

  18. Crystallization and preliminary X-ray diffraction analysis of a soluble domain of the putative zinc transporter CzrB from Thermus thermophilus

    International Nuclear Information System (INIS)

    Diffraction-quality crystals of the apo (1.7 Å) and zinc-bound forms (2.2 Å) of the water-soluble C-terminal domain of the putative zinc transporter CzrB from T. thermophilus have been grown using recombinant production of the protein in E. coli and a combination of vapour-diffusion, batch and seeding crystallogenesis techniques. CzrB is a putative zinc transporter from Thermus thermophilus. The protein is proposed to consist of a hexahelical transmembrane domain with a cytosolic extramembranal C-terminus. The latter 92-residue fragment may be expressed free and may function independently of the full-length integral membrane protein. A 6×His-tagged form of the water-soluble fragment has been overexpressed in Escherichia coli and diffraction-quality crystals of the tagged and tag-free variants have been grown. Preliminary X-ray analyses of tag-free fragment crystals with (2.2 Å resolution) and without zinc ions (1.7 Å resolution) reveal that the former has at least two zinc ions bound per monomer

  19. Functional expression of a penicillin acylase from the extreme thermophile Thermus thermophilus HB27 in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Torres Leticia L

    2012-08-01

    Full Text Available Abstract Background Penicillin acylases (PACs are enzymes of industrial relevance in the manufacture of β-lactam antibiotics. Development of a PAC with a longer half-life under the reaction conditions used is essential for the improvement of the operational stability of the process. A gene encoding a homologue to Escherichia coli PAC was found in the genome of the thermophilic bacterium Thermus thermophilus (Tth HB27. Because of the nature of this PAC and its complex maturation that is crucial to reach its functional heterodimeric final conformation, the overexpression of this enzyme in a heterologous mesophilic host was a challenge. Here we describe the purification and characterization of the PAC protein from Tth HB27 overexpressed in Escherichia coli. Results Fusions to a superfolder green fluorescent protein and differential membrane solubilization assays indicated that the native enzyme remains attached through its amino-terminal end to the outer side of the cytoplasmic membrane of Tth cells. In order to overexpress this PAC in E. coli cells, a variant of the protein devoid of its membrane anchoring segment was constructed. The effect of the co-expression of chaperones and calcium supplementation of the culture medium was investigated. The total production of PAC was enhanced by the presence of DnaK/J and GrpE and even more by trigger factor and GroEL/ES. In addition, 10 mM calcium markedly improved both PAC specific and volumetric activities. Recombinant PAC was affinity-purified and proper maturation of the protein was confirmed by SDS-PAGE and MALDI-TOF analysis of the subunits. The recombinant protein was tested for activity towards several penicillins, cephalosporins and homoserine lactones. Hydrophobic acyl-chain penicillins were preferred over the rest of the substrates. Penicillin K (octanoyl penicillin was the best substrate, with the highest specificity constant value (16.12 mM-1.seg-1. The optimum pH was aprox. 4 and the optimum

  20. High resolution structure of the ba3 cytochrome c oxidase from Thermus thermophilus in a lipidic environment.

    Directory of Open Access Journals (Sweden)

    Theresa Tiefenbrunn

    Full Text Available The fundamental chemistry underpinning aerobic life on Earth involves reduction of dioxygen to water with concomitant proton translocation. This process is catalyzed by members of the heme-copper oxidase (HCO superfamily. Despite the availability of crystal structures for all types of HCO, the mode of action for this enzyme is not understood at the atomic level, namely how vectorial H(+ and e(- transport are coupled. Toward addressing this problem, we report wild type and A120F mutant structures of the ba(3-type cytochrome c oxidase from Thermus thermophilus at 1.8 Å resolution. The enzyme has been crystallized from the lipidic cubic phase, which mimics the biological membrane environment. The structures reveal 20 ordered lipid molecules that occupy binding sites on the protein surface or mediate crystal packing interfaces. The interior of the protein encloses 53 water molecules, including 3 trapped in the designated K-path of proton transfer and 8 in a cluster seen also in A-type enzymes that likely functions in egress of product water and proton translocation. The hydrophobic O(2-uptake channel, connecting the active site to the lipid bilayer, contains a single water molecule nearest the Cu(B atom but otherwise exhibits no residual electron density. The active site contains strong electron density for a pair of bonded atoms bridging the heme Fe(a3 and Cu(B atoms that is best modeled as peroxide. The structure of ba(3-oxidase reveals new information about the positioning of the enzyme within the membrane and the nature of its interactions with lipid molecules. The atomic resolution details provide insight into the mechanisms of electron transfer, oxygen diffusion into the active site, reduction of oxygen to water, and pumping of protons across the membrane. The development of a robust system for production of ba(3-oxidase crystals diffracting to high resolution, together with an established expression system for generating mutants, opens the

  1. 东太平洋海隆热液区嗜热深海偏顶蛤(Bathymodiolus thermophilus)的形态和分布特征%Characteristics of morphology and distribution about Bathymodiolus thermophilus from hydrothermal area of the EPR

    Institute of Scientific and Technical Information of China (English)

    王建佳; 林荣澄; 黄丁勇; 刘昕明; 牛文涛

    2013-01-01

    在2009-2010年的中国大洋第21航次环球科学考察中, “大洋一号”考察船对东太平洋海隆1.2°N周边新发现的“宝石山”热液区进行了综合调查,并利用我国自主研发的电视抓斗采集到了贻贝类样品,经形态学研究鉴定为嗜热深海偏顶蛤Bathymodiolus thermophilus,Kenk&Wilson,1985,这是此物种在该区域分布的新纪录.文章对样品进行了详细描述,并与其它海区发现的B.thermophilus进行了形态学上的比较和讨论.%During the 21st ocean survey of China during 2009-2010,the vessel " DA YANG YI HAO" made a comprehensive investigation in the hydrothermal area of the new discovered 'Precious Stone Mountain' surrounding 1.2 °N of the EPR,and it acquired some specimens of Mytilidae by use of the independently researched and developed TV-Grab.After morphological researches,we identified these specimens as Bathymodiolus thermophilus,Kenk & Wilson,1985.This is new record in the regional distribution of B.thermophilus.The article described the samples,and carried out some morphological comparations and discussions with this species found from other areas.

  2. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to beta-galactosidase from Streptococcus thermophilus and reduction of gastrointestinal discomfort pursuant to Article 14 of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    deliver an opinion on the scientific substantiation of a health claim related to beta-galactosidase from Streptococcus thermophilus and reduction of gastrointestinal discomfort. According to the applicant, the food constituent which is the subject of the claim is beta-galactosidase from Streptococcus...... thermophilus. Streptococcus thermophilus is added to infant formulae in the production process for fermentation purposes and the live organisms are inactivated after the fermentation process. The Panel considers that the food constituent, beta-galactosidase from Streptococcus thermophilus, under the conditions...... of use proposed by the applicant, is sufficiently characterised. The claimed effect proposed by the applicant is “reduction of gastro-intestinal discomfort”. The target population proposed by the applicant is infants and young children. The Panel considers that reduction of gastrointestinal...

  3. Dicty_cDB: Contig-U01651-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available sapiens mRNA for FLJ00032 pro... 35 4.3 CU928165_180( CU928165 |pid:none) Kluyveromyces thermotoler...CP001034_1554( CP001034 |pid:none) Natranaerobius thermophilus JW/... 33 9.5 AK290475_1( AK290475 |pid:none) Homo...centrotus pulcherrimus BAC clone: BUB1-08B10_... 48 0.57 1 ( BX567647 ) Glossina morsitans morsi...ts to DB: 1,023,198,253 Number of extensions: 65930039 Number of successful extensions: 5917718 Number of sequences better th... of extensions: 19201541 Number of successful extensions: 55778 Number of sequences better th

  4. Crystallization and preliminary X-ray analysis of the oxygenase component (HpaB) of 4-hydroxyphenylacetate 3-monooxygenase from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    Crystals of the oxygenase component (HpaB) of 4-hydroxyphenylacetate 3-monooxygenase from T. thermophilus HB8 were obtained which diffracted synchrotron X-rays to a resolution of 1.6 Å. The 4-hydroxyphenylacetate (4HPA) 3-monooxygenase enzyme catalyzes the hydroxylation of 4HPA to 3,4-dihydroxyphenylacetate in the initial step of the degradation pathway of 4HPA. This enzyme consists of two components: an oxygenase (HpaB) and a reductase (HpaC). HpaB hydroxylates 4HPA using an oxygen molecule and a reduced flavin, which is supplied by HpaC. HpaB from Thermus thermophilus HB8 was overexpressed in Escherichia coli and crystallized. Crystals of HpaB were grown in 0.4 M 1,6-hexanediol, 0.1 M sodium acetate pH 5.0 and 25%(v/v) glycerol and diffracted X-rays to a resolution of 1.60 Å. The crystals belong to the orthorhombic space group I222, with unit-cell parameters a = 91.8, b = 99.6, c = 131.1 Å. The asymmetric unit volume provides space for only one subunit of the tetrameric HpaB molecule, giving a Matthews coefficient VM of 2.8 Å3 Da−1 and a solvent content of 55.1%. Platinum-derivatized crystals of HpaB were prepared by soaking native crystals in a solution containing 1 mM ammonium tetrachloroplatinate(II) for 1 d and diffracted X-rays to a resolution of 2.50 Å. MAD data were successfully collected for structural determination using these crystals

  5. High-resolution structures of Thermus thermophilus enoyl-acyl carrier protein reductase in the apo form, in complex with NAD+ and in complex with NAD+ and triclosan

    International Nuclear Information System (INIS)

    T. thermophilus enoyl-acyl carrier protein reductase was crystallized in the apo form, with NAD+ bound and with NAD+ and the inhibitor triclosan bound. The structures were solved by molecular replacement and refined at 1.50, 1.86 and 1.90 Å resolution, respectively. The structures are described, analysed and compared with those of enoyl-acyl carrier protein reductases from other species. Enoyl-acyl carrier protein reductase (ENR; the product of the fabI gene) is an important enzyme that is involved in the type II fatty-acid-synthesis pathway of bacteria, plants, apicomplexan protozoa and mitochondria. Harmful pathogens such as Mycobacterium tuberculosis and Plasmodium falciparum use the type II fatty-acid-synthesis system, but not mammals or fungi, which contain a type I fatty-acid-synthesis pathway consisting of one or two multifunctional enzymes. For this reason, specific inhibitors of ENR are attractive antibiotic candidates. Triclosan, a broad-range antibacterial agent, binds to ENR, inhibiting fatty-acid synthesis. As humans do not have an ENR enzyme, they are not affected. Here, high-resolution structures of Thermus thermophilus (Tth) ENR in the apo form, bound to NAD+ and bound to NAD+ plus triclosan are reported. Differences from and similarities to other known ENR structures are reported; in general, the structures are very similar. The cofactor-binding site is also very similar to those of other ENRs and, as reported for other species, triclosan leads to greater ordering of the loop that covers the cofactor-binding site, which, together with the presence of triclosan itself, presumably provides tight binding of the dinucleotide, preventing cycling of the cofactor. Differences between the structures of Tth ENR and other ENRs are the presence of an additional β-sheet at the N-terminus and a larger number of salt bridges and side-chain hydrogen bonds. These features may be related to the high thermal stability of Tth ENR

  6. Sugar Utilization and Acid Production by Free and Entrapped Cells of Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Lactococcus lactis subsp. lactis in a Whey Permeate Medium

    Science.gov (United States)

    Audet, Pascal; Paquin, Celine; Lacroix, Christophe

    1989-01-01

    Cells of Streptococcus salivarius subsp. thermophilus and Lactococcus lactis subsp. lactis entrapped in k-carrageenan-locust bean gum gel performed similarly to free cells in the conversion of lactose to lactic acid. Bead diameter influenced the fermentation rate. Cells entrapped in smaller beads (0.5 to 1.0 mm) showed higher release rates, higher lactose, glucose, and formic acid utilization, higher galactose accumulation, and higher lactic acid production than did cells entrapped in larger beads (1.0 to 2.0 mm). Values for smaller beads were comparable with those for free cells. Immobilization affected the fermentation rate of lactic acid bacteria, especially Lactobacillus delbrueckii subsp. bulgaricus. Entrapped cells of L. delbrueckii subsp. bulgaricus demonstrated a lower lactic acid production than did free cells in batch fermentation. The kinetics of the production of formic and pyruvic acids by L. lactis subsp. lactis and S. salivarius subsp. thermophilus are presented. PMID:16347822

  7. Identification of the outer membrane porin of Thermus thermophilus HB8: the channel-forming complex has an unusually high molecular mass and an extremely large single-channel conductance.

    Science.gov (United States)

    Maier, E; Polleichtner, G; Boeck, B; Schinzel, R; Benz, R

    2001-01-01

    The outer membrane of the thermophilic bacterium Thermus thermophilus was isolated using sucrose step gradient centrifugation. Its detergent extracts contained an ion-permeable channel with an extremely high single-channel conductance of 20 nS in 1 M KCl. The channel protein was purified by preparative sodium dodecyl sulfate (SDS)-polyacylamide gel electrophoresis. It has a high molecular mass of 185 kDa, and its channel-forming ability resists boiling in SDS for 10 min. PMID:11133980

  8. Identification of the Outer Membrane Porin of Thermus thermophilus HB8: the Channel-Forming Complex Has an Unusually High Molecular Mass and an Extremely Large Single-Channel Conductance

    OpenAIRE

    Maier, Elke; Polleichtner, Georg; Boeck, Birgit; Schinzel, Reinhard; Benz, Roland

    2001-01-01

    The outer membrane of the thermophilic bacterium Thermus thermophilus was isolated using sucrose step gradient centrifugation. Its detergent extracts contained an ion-permeable channel with an extremely high single-channel conductance of 20 nS in 1 M KCl. The channel protein was purified by preparative sodium dodecyl sulfate (SDS)-polyacylamide gel electrophoresis. It has a high molecular mass of 185 kDa, and its channel-forming ability resists boiling in SDS for 10 min.

  9. Enhanced Heavy Metal Tolerance and Accumulation by Transgenic Sugar Beets Expressing Streptococcus thermophilus StGCS-GS in the Presence of Cd, Zn and Cu Alone or in Combination

    OpenAIRE

    Liu, Dali; An, Zhigang; Mao, Zijun; Ma, Longbiao; Lu, Zhenqiang

    2015-01-01

    Phytoremediation is a promising means of ameliorating heavy metal pollution through the use of transgenic plants as artificial hyperaccumulators. A novel Streptococcus thermophilus γ-glutamylcysteine synthetase-glutathione synthetase (StGCS-GS) that synthesizes glutathione (GSH) with limited feedback inhibition was overexpressed in sugar beet (Beta vulgaris L.), yielding three transgenic lines (s2, s4 and s5) with enhanced tolerance to different concentrations of cadmium, zinc and copper, as ...

  10. Study on the effect of melamine on the growth of Streptococcus thermophilus%三聚氰胺对嗜热链球菌生长影响的研究

    Institute of Scientific and Technical Information of China (English)

    郭丽琼; 田雪琴; 苏霞; 吴厚玖; 曹秋旭; 董文博

    2012-01-01

    通过在MRS液体培养基里分别添加0‰、0.25‰、0.5‰、1‰、2‰、3‰及饱和的三聚氰胺,接种嗜热链球菌,在42℃下培养48h,通过测定培养液的pH变化和计数细菌总数来考察三聚氰胺对嗜热链球菌生长的影响。结果表明:嗜热链球菌不能以三聚氰胺为氮源物质而加以降解利用,三聚氰胺在水溶解度范围内对嗜热链球菌的生长没有促进作用,只有微弱的抑制效果。%MRS liquid mediums added respectively with 0‰,0.25‰,0.5‰,1‰,2‰,3‰ and saturation concentration melamine were used to cultivate Streptococcus thermophilus.After 48h at 42℃ in the culture medium,the impaction of melamine on the growth of Streptococcus thermophilus was tested through measuring the pH of the medium and calculating the final total number of bacteria.The experimental results showed that melamine couldn't be used and degraded by Streptococcus thermophilus as a nitrogen and melamine within the water solubility couldn't promote the growth of Streptococcus thermophilus while it had a little inhibition effect on the growth of it.

  11. Structure of a conserved hypothetical protein, TTHA0849 from Thermus thermophilus HB8, at 2.4 Å resolution: a putative member of the StAR-related lipid-transfer (START) domain superfamily

    International Nuclear Information System (INIS)

    The crystal structure of a conserved hypothetical protein, TTHA0849 from T. thermophilus HB8, has been determined at 2.4 Å resolution. The compact α+β structure shows the typical folding of the steroidogenic acute regulatory-related lipid-transfer (START) domain. The crystal structure of a conserved hypothetical protein, TTHA0849 from Thermus thermophilus HB8, has been determined at 2.4 Å resolution as a part of a structural and functional genomics project on T. thermophilus HB8. The main-chain folding shows a compact α+β motif, forming a hydrophobic cavity in the molecule. A structural similarity search reveals that it resembles those steroidogenic acute regulatory proteins that contain the lipid-transfer (START) domain, even though TTHA0849 shows comparatively weak sequence identity to polyketide cyclases. However, the size of the ligand-binding cavity is distinctly smaller than other START domain-containing proteins, suggesting that it catalyses the transfer of smaller ligand molecules

  12. Use of the dynamic gastro-intestinal model TIM to explore the survival of the yogurt bacterium Streptococcus thermophilus and the metabolic activities induced in the simulated human gut.

    Science.gov (United States)

    Uriot, Ophélie; Galia, Wessam; Awussi, Ahoefa Ablavi; Perrin, Clarisse; Denis, Sylvain; Chalancon, Sandrine; Lorson, Emilie; Poirson, Chantal; Junjua, Maira; Le Roux, Yves; Alric, Monique; Dary, Annie; Blanquet-Diot, Stéphanie; Roussel, Yvonne

    2016-02-01

    Streptococcus thermophilus, a lactic acid bacterium used to produce yogurts and cheeses is more and more considered for its potential probiotic properties. This implies that additional information should be obtained regarding its survival and metabolic activity in the human Gastro-Intestinal Tract (GIT). In this study, we screened 30 S. thermophilus strains for urease, small heat shock protein, and amino-acid decarboxylase functions which may play a role in survival in the upper part of the GIT. The survival kinetics of 4 strains was investigated using the TIM, a physiologically relevant in vitro dynamic gastric and small intestinal model. The three strains LMD9, PB18O and EBLST20 showed significantly higher survival than CNRZ21 in all digestive compartments of the TIM, which may be related to the presence of urease and heat shock protein functions. When LMD9 bacterial cells were delivered in a fermented milk formula, a significant improvement of survival in the TIM was observed compared to non-fermented milk. With the RIVET (Recombinase In Vivo Expression Technology) method applied to the LMD9 strain, a promoter located upstream of hisS, responsible for the histidyl-transfer RNA synthesis, was found to be specifically activated in the artificial stomach. The data generated on S. thermophilus survival and its adaptation capacities to the digestive tract are essential to establish a list of biomarkers useful for the selection of probiotic strains. PMID:26611166

  13. Use of microparticulated whey protein concentrate, exopolysaccharide-producing Streptococcus thermophilus, and adjunct cultures for making low-fat Italian Caciotta-type cheese.

    Science.gov (United States)

    Di Cagno, R; De Pasquale, I; De Angelis, M; Buchin, S; Rizzello, C G; Gobbetti, M

    2014-01-01

    Low-fat Caciotta-type cheeses were manufactured with partially skim milk (fat content of ~0.3%) alone (LFC); with the supplementation of 0.5% (wt/vol) microparticulated whey protein concentrate (MWPC) (LFC-MWPC); with MWPC and exopolysaccharides (EPS)-producing Streptococcus thermophilus ST446 (LFC-MWPC-EPS); and with MWPC, EPS-producing strain ST446, and Lactobacillus plantarum LP and Lactobacillus rhamnosus LRA as adjunct cultures (LFC-MWPC-EPS-A). The non-EPS-producing isogenic variant Streptococcus thermophilus ST042 was used for making full-fat Caciotta-type cheese (FFC), LFC, and LFC-MWPC. Cheeses were characterized based on compositional, microbiological, biochemical, texture, volatile components (purge and trap, and solid-phase microextraction coupled with gas chromatography-mass spectrometry), and sensory analyses. Compared with FFC and LFC (51.6 ± 0.7 to 53.0 ± 0.9%), the other cheese variants retained higher levels of moisture (60.5 ± 1.1 to 67.5 ± 0.5%). The MWPC mainly contributed to moisture retention. Overall, all LFC had approximately one-fourth (22.6 ± 0.8%) of the fat of FFC. Hardness of cheeses slightly varied over 7d of ripening. Microbial EPS positively affected cheese texture, and the texture of LFC without MWPC or microbial EPS was excessively firm. Free amino acids were at the highest levels in LFC treatments (2,705.8 ± 122 to 3,070.4 ± 123 mg/kg) due to the addition of MWPC and the peptidase activity of adjunct cultures. Aldehydes, alcohols, ketones, sulfur compounds, and short- to medium-chain carboxylic acids differentiated LFC variants and FFC. The sensory attributes pleasant to taste, intensity of flavor, overall acceptability, and pleasant to chew variously described LFC-MWPC-EPS and LFC-MWPC-EPS-A. Based on the technology options used, low-fat Caciotta-type cheese (especially ripened for 14 d) has promising features to be further exploited as a suitable alternative to the full-fat variant. PMID:24183686

  14. Adesão de linhagem selvagem de Streptococcus thermophilus em superfície de aço inoxidável e efeitos da higienização na sua remoção Adhesion of a wild strain of Streptococcus thermophilus onto stainless steel surfaces and the effects of cleaning and sanification on its removal

    OpenAIRE

    Ana Lourdes Neves GÂNDARA; OLIVEIRA José Sátiro de

    2000-01-01

    Linhagem selvagem de Streptococcus thermophilus isolada de leite pasteurizado foi avaliada em modelo experimental quanto a adesão em superfície de aço inoxidável e comportamento frente à limpeza e sanificação. Em leite, a adesão do microrganismo em aço inoxidável foi estudada em 6h de contato a 45°C sob agitação e uma higienização com detergentes alcalino e ácido seguida de sanificação foi utilizada para avaliação do comportamento das células aderidas frente à higienização. Esse microrganismo...

  15. Comparison of the backbone dynamics of wild-type Hydrogenobacter thermophilus cytochrome c{sub 552} and its b-type variant

    Energy Technology Data Exchange (ETDEWEB)

    Tozawa, Kaeko; Ferguson, Stuart J.; Redfield, Christina, E-mail: christina.redfield@bioch.ox.ac.uk [University of Oxford, Department of Biochemistry (United Kingdom); Smith, Lorna J., E-mail: lorna.smith@chem.ox.ac.uk [University of Oxford, Department of Chemistry (United Kingdom)

    2015-06-15

    Cytochrome c{sub 552} from the thermophilic bacterium Hydrogenobacter thermophilus is a typical c-type cytochrome which binds heme covalently via two thioether bonds between the two heme vinyl groups and two cysteine thiol groups in a CXXCH sequence motif. This protein was converted to a b-type cytochrome by substitution of the two cysteine residues by alanines (Tomlinson and Ferguson in Proc Natl Acad Sci USA 97:5156–5160, 2000a). To probe the significance of the covalent attachment of the heme in the c-type protein, {sup 15}N relaxation and hydrogen exchange studies have been performed for the wild-type and b-type proteins. The two variants share very similar backbone dynamic properties, both proteins showing high {sup 15}N order parameters in the four main helices, with reduced values in an exposed loop region (residues 18–21), and at the C-terminal residue Lys80. Some subtle changes in chemical shift and hydrogen exchange protection are seen between the wild-type and b-type variant proteins, not only for residues at and neighbouring the mutation sites, but also for some residues in the heme binding pocket. Overall, the results suggest that the main role of the covalent linkages between the heme group and the protein chain must be to increase the stability of the protein.

  16. The structure of putative N-acetyl glutamate kinase from Thermus thermophilus reveals an intermediate active site conformation of the enzyme.

    Science.gov (United States)

    Sundaresan, Ramya; Ragunathan, Preethi; Kuramitsu, Seiki; Yokoyama, Shigeyuki; Kumarevel, Thirumananseri; Ponnuraj, Karthe

    2012-04-13

    The de novo biosynthesis of arginine in microorganisms and plants is accomplished via several enzymatic steps. The enzyme N-acetyl glutamate kinase (NAGK) catalyzes the phosphorylation of the γ-COO(-) group of N-acetyl-L-glutamate (NAG) by adenosine triphosphate (ATP) which is the second rate limiting step in arginine biosynthesis pathway. Here we report the crystal structure of putative N-acetyl glutamate kinase (NAGK) from Thermus thermophilus HB8 (TtNAGK) determined at 1.92Å resolution. The structural analysis of TtNAGK suggests that the dimeric quaternary state of the enzyme and arginine insensitive nature are similar to mesophilic Escherichia coli NAGK. These features are significantly different from its thermophilic homolog Thermatoga maritima NAGK which is hexameric and arginine-sensitive. TtNAGK is devoid of its substrates but contains two sulfates at the active site. Very interestingly the active site of the enzyme adopts a conformation which is not completely open or closed and likely represents an intermediate stage in the catalytic cycle unlike its structural homologs, which all exist either in the open or closed conformation. Engineering arginine biosynthesis pathway enzymes for the production of l-arginine is an important industrial application. The structural comparison of TtNAGK with EcNAGK revealed the structural basis of thermostability of TtNAGK and this information could be very useful to generate mutants of NAGK with increased overall stability. PMID:22452987

  17. The activity of the lactose transporter from Streptococcus thermophilus is increased by phosphorylated IIA and the action of beta-galactosidase.

    Science.gov (United States)

    Geertsma, Eric R; Duurkens, Ria H; Poolman, Bert

    2005-12-01

    The metabolism of lactose by Streptococcus thermophilus is highly regulated, allowing the bacterium to prefer lactose over glucose as main source of carbon and energy. In vitro analysis of the enzymes involved in transport and hydrolysis of lactose showed that the transport reaction benefits from the hydrolysis of lactose at the trans side of the membrane. Furthermore, the activity of LacS is modulated by PEP-dependent phosphorylation of the IIA domain via the general energy coupling proteins of the PTS, Enzyme I and HPr. To determine whether unphosphorylated LacS-IIA inhibited, or the phosphorylated form stimulated lactose counterflow, a LacS-IIA truncation mutant of LacS was constructed. Detailed analyses of transport in whole cells and in proteoliposomes indicated that unphosphorylated LacS-IIA does not functionally interact with the carrier domain. Instead, interaction of the phosphorylated form of LacS-IIA with the carrier stimulates lactose counterflow transport. The proposed mode of regulation thus proceeds via a mechanism opposite to the inducer exclusion type of regulation in gram-negative bacteria, where transporters are inhibited by binding of the unphosphorylated form of IIA(Glc). PMID:16313191

  18. A Flexible Domain-Domain Hinge Promotes an Induced-fit Dominant Mechanism for the Loading of Guide-DNA into Argonaute Protein in Thermus thermophilus.

    Science.gov (United States)

    Zhu, Lizhe; Jiang, Hanlun; Sheong, Fu Kit; Cui, Xuefeng; Gao, Xin; Wang, Yanli; Huang, Xuhui

    2016-03-17

    Argonaute proteins (Ago) are core components of the RNA Induced Silencing Complex (RISC) that load and utilize small guide nucleic acids to silence mRNAs or cleave foreign DNAs. Despite the essential role of Ago in gene regulation and defense against virus, the molecular mechanism of guide-strand loading into Ago remains unclear. We explore such a mechanism in the bacterium Thermus thermophilus Ago (TtAgo), via a computational approach combining molecular dynamics, bias-exchange metadynamics, and protein-DNA docking. We show that apo TtAgo adopts multiple closed states that are unable to accommodate guide-DNA. Conformations able to accommodate the guide are beyond the reach of thermal fluctuations from the closed states. These results suggest an induced-fit dominant mechanism for guide-strand loading in TtAgo, drastically different from the two-step mechanism for human Ago 2 (hAgo2) identified in our previous study. Such a difference between TtAgo and hAgo2 is found to mainly originate from the distinct rigidity of their L1-PAZ hinge. Further comparison among known Ago structures from various species indicates that the L1-PAZ hinge may be flexible in general for prokaryotic Ago's but rigid for eukaryotic Ago's. PMID:26908081

  19. Ribosomes containing mutants of L4 ribosomal protein from Thermus thermophilus display multiple defects in ribosomal functions and sensitivity against erythromycin

    Science.gov (United States)

    TSAGKALIA, AIKATERINI; LEONTIADOU, FOTINI; XAPLANTERI, MARIA A.; PAPADOPOULOS, GEORGIOS; KALPAXIS, DIMITRIOS L.; CHOLI-PAPADOPOULOU, THEODORA

    2005-01-01

    Protein L4 from Thermus thermophilus (TthL4) was heterologously overproduced in Escherichia coli cells. To study the implication of the extended loop of TthL4 in the exit-tunnel and peptidyltransferase functions, the highly conserved E56 was replaced by D or Q, while the semiconserved G55 was changed to E or S. Moreover, the sequence -G55E56- was inverted to -E55G56-. When we incorporated these mutants into E. coli ribosomes and investigated their impact on poly(Phe) synthesis, high variations in the synthetic activity and response to erythromycin of the resulting ribosomes were observed. In the absence of erythromycin, ribosomes harboring mutations G55E and E56D in TthL4 protein were characterized by low activity in synthesizing poly(Phe) and decreased capability in binding tRNA at the A site. On the other hand, ribosomes possessing mutations G55E, G55S, G55E-E56G, or E56Q in TthL4 protein were unexpectedly more sensitive to erythromycin. Evidence in support of these findings was drawn by in vivo experiments, assessing the erythromycin sensitivity of E. coli cells expressing wild-type or mutant TthL4 proteins. Our results emphasize the role of the extended loop of L4 ribosomal protein in the exit-tunnel and peptidyltransferase center functions. PMID:16244130

  20. Improved Helicobacter pylori Eradication Rate of Tailored Triple Therapy by Adding Lactobacillus delbrueckii and Streptococcus thermophilus in Northeast Region of Thailand: A Prospective Randomized Controlled Clinical Trial

    Directory of Open Access Journals (Sweden)

    Taweesak Tongtawee

    2015-01-01

    Full Text Available Background and Aim. To evaluate the effect of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus to Helicobacter pylori eradication in different periods of therapeutic protocol. Methods. Infected patients were randomized to one-week tailored triple therapy (esomeprazole 20 mg bid, clarithromycin 500 mg bid/metronidazole 400 mg tid if clarithromycin resistant, and amoxicillin 1000 mg bid with placebo (group 1, n=100; one week of pretreatment with probiotics (group 2, n=100; and one week of pretreatment with probiotic followed by one week of the same probiotics after treatment (group 3, n=100. Result. PP analysis involved 292 patients, 98 in group 1, 97 in group 2, and 97 in group 3. Successful eradication was observed in 229 patients; by PP analysis, the eradication rates were significantly higher (P<0.01, 95% CI; 0.71–0.97 in group 2 and group 3 than group 1. ITT analysis eradication rates were significantly higher in group 2 and group 3 than group 1 (P<0.01 95% CI; 0.72–0.87, and there is no significant difference between the three groups (P=0.32 in terms of adverse events. Conclusion. Adding probiotics before or before and after tailored treatment can improve Helicobacter pylori eradication rates. This trial is registered with Thai Clinical Trials Registry number: TCTR20141209001.

  1. Comparative Analysis of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) of Streptococcus thermophilus St-I and its Bacteriophage-Insensitive Mutants (BIM) Derivatives.

    Science.gov (United States)

    Li, Wan; Bian, Xin; Evivie, Smith Etareri; Huo, Gui-Cheng

    2016-09-01

    The CRISPR-Cas (CRISPR together with CRISPR-associated proteins) modules are the adaptive immune system, acting as an adaptive and heritable immune system in bacteria and archaea. CRISPR-based immunity acts by integrating short virus sequences in the cell's CRISPR locus, allowing the cell to remember, recognize, and clear infections. In this study, the homology of CRISPRs sequence in BIMs (bacteriophage-insensitive mutants) of Streptococcus thermophilus St-I were analyzed. Secondary structures of the repeats and the PAMs (protospacer-associated motif) of each CRISPR locus were also predicted. Results showed that CRISPR1 has 27 repeat-spacer units, 5 of them had duplicates; CRISPR2 has one repeat-spacer unit; CRISPR3 has 28 repeat-spacer units. Only BIM1 had a new spacer acquisition in CRISPR3, while BIM2 and BIM3 had no new spacers' insertion, thus indicating that while most CRISPR1 were more active than CRISPR3, new spacer acquisition occurred just in CRSPR3 in some situations. These findings will help establish the foundation for the study of CRSPR-Cas systems in lactic acid bacteria. PMID:27378131

  2. Structural basis for the hydrolysis of ATP by a nucleotide binding subunit of an amino acid ABC transporter from Thermus thermophilus.

    Science.gov (United States)

    Devi, Seenivasan Karthiga; Chichili, Vishnu Priyanka Reddy; Jeyakanthan, J; Velmurugan, D; Sivaraman, J

    2015-06-01

    ATP-binding cassette (ABC) transporters are a major family of small molecule transporter proteins, and their deregulation is associated with several diseases, including cancer. Here, we report the crystal structure of the nucleotide binding domain (NBD) of an amino acid ABC transporter from Thermus thermophilus (TTHA1159) in its apo form and as a complex with ADP along with functional studies. TTHA1159 is a putative arginine ABC transporter. The apo-TTHA1159 was crystallized in dimeric form, a hitherto unreported form of an apo NBD. Structural comparison of the apo and ADP-Mg(2+) complexes revealed that Phe14 of TTHA1159 undergoes a significant conformational change to accommodate ADP, and that the bound ADP interacts with the P-loop (Gly40-Thr45). Modeling of ATP-Mg(2+):TTHA1159 complex revealed that Gln86 and Glu164 are involved in water-mediated hydrogen bonding contacts and Asp163 in Mg(2+) ion-mediated hydrogen bonding contacts with the γ-phosphate of ATP, consistent with the findings of other ABC transporters. Mutational studies confirmed the necessity of each of these residues, and a comparison of the apo/ADP Mg(2+):TTHA1159 with its ATP-complex model suggests the likelihood of a key conformational change to the Gln86 side chain for ATP hydrolysis. PMID:25916755

  3. Improved Growth of Lactobacillus bulgaricus and Streptococcus thermophilus as well as Increased Antioxidant Activity by Biotransforming Litchi Pericarp Polysaccharide with Aspergillus awamori

    Directory of Open Access Journals (Sweden)

    Sen Lin

    2013-01-01

    Full Text Available This study was conducted to increase the bioactivity of litchi pericarp polysaccharides (LPPs biotransformed by Aspergillus awamori. Compared to the non-A. awamori-fermented LPP, the growth effects of A. awamori-fermented LPP on Lactobacillus bulgaricus and Streptococcus thermophilus were four and two times higher after 3 days of fermentation, respectively. Increased 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and DNA protection activity of litchi pericarp polysaccharides were also achieved after A. awamori fermentation. Moreover, the relative content of glucose and arabinose in LPP after fermentation decreased from 58.82% to 22.60% and from 18.82% to 10.09%, respectively, with a concomitant increase in the relative contents of galactose, rhamnose, xylose, and mannose. Furthermore, lower molecular weight polysaccharides were obtained after A. awamori fermentation. It can be concluded that A. awamori was effective in biotransforming LPP into a bioactive mixture with lower molecular weight polysaccharides and higher antioxidant activity and relative galactose content.

  4. Characteristics of third-generation glucose biosensors based on Corynascus thermophilus cellobiose dehydrogenase immobilized on commercially available screen-printed electrodes working under physiological conditions.

    Science.gov (United States)

    Zafar, Muhammad Nadeem; Safina, Gulnara; Ludwig, Roland; Gorton, Lo

    2012-06-01

    In this article, we describe a third-generation amperometric glucose biosensor working under physiological conditions. This glucose biosensor consists of a recently discovered cellobiose dehydrogenase from the ascomycete Corynascus thermophilus (CtCDH) immobilized on different commercially available screen-printed electrodes made of carbon (SPCEs), carboxyl-functionalized single-walled carbon nanotubes (SPCE-SWCNTs), or multiwalled carbon nanotubes (SPCE-MWCNTs) by simple physical adsorption or a combination of adsorption followed by cross-linking using poly(ethyleneglycol) (400) diglycidyl ether (PEGDGE) or glutaraldehyde (GA). The CtCDH-based third-generation glucose biosensor has a linear range between 0.025 and 30 mM and a detection limit of 10 μM glucose. Biosensors based on SWCNTs showed a higher sensitivity and catalytic response than the ones functionalized with MWCNTs and the SPCEs. A drastic increase in response was observed for all three electrodes when the adsorbed enzyme was cross-linked with PEGDGE or GA. The operational stability of the biosensor was tested for 7 h by repeated injections of 50 mM glucose, and only a slight decrease in the electrochemical response was found. The selectivity of the CtCDH-based biosensor was tested on other potentially interfering carbohydrates such as mannose, galactose, sucrose, and fucose that might be present in blood. No significant analytical response from any of these compounds was observed. PMID:22381371

  5. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and

    DEFF Research Database (Denmark)

    Tetens, Inge

    to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort. The food that is the subject of the health claim is a combination of four bacterial strains—B. longum LA 101, L....... helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104. The Panel considers that the food, a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104, which is the subject of the health claim is sufficiently characterised. The claimed effect proposed by the...... applicant is "improves intestinal comfort". The Panel considers that reduction of gastro-intestinal discomfort is a beneficial physiological effect. The Panel considers that the only human study provided for the substantiation of the claim (with limitations) did not find an effect of a combination of the...

  6. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium logum LA 10, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing

    DEFF Research Database (Denmark)

    Tetens, Inge

    substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort. The food that is the subject of the health claim is a combination of B. longum LA 101, L...... and effect relationship cannot be established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103, and S. thermophilus LA 104 and reducing intestinal discomfort. © European Food Safety Authority, 2013...

  7. On the Thermus thermophilus HB8 potential pathogenicity triggered from rhamnolipids secretion: morphological alterations and cytotoxicity induced on fibroblastic cell line.

    Science.gov (United States)

    Pantazaki, A A; Choli-Papadopoulou, T

    2012-05-01

    A limited number of bacterial strains usually grown under nutrient limitation secrete rhamnolipids (RLs), which are recorded as virulence factors that are implicated in the pathogenicity of a microorganism. The non-pathogenic T. thermophilus HB8 produces extracellular rhamnolipids (TthRLs) under defined cultivation conditions using sunflower seed oil and sodium gluconate as carbon sources. In particular, the secreted TthRLs have been isolated, purified and identified with ATR-FTIR. Their effects on the cells' viability were examined when they were supplemented in a culture of human skin fibroblasts. Purified TthRLs triggered a sequence of rapid and pronounced morphological alterations characterized by transformation of fibroblast shape from polygonal to fusiform; retraction with cytoplasm condensation, rounding up, distortion of nuclei and loss of lamellar processes, and finally disruption of membrane. The addition of TthRLs in the cultured fibroblasts caused cytotoxicity, in contrast to that of rhamnose that stimulated viability, as it was assessed by MTT test. These results revealed that among the constituents of RLs that are implicated in the cytotoxicity, it has to be attributed to the lipidic chain variation and not to the carbohydrate part. TthRLs cytotoxicity on fibroblasts is comparable, and provoked similar effects, to that caused by saponin white, a known surfactant. TthRLs secretion might be a crucial point for the transformation of a non-pathogenic bacterium to a pathogenic one under certain environmental conditions favoring their secretion. RLs secretion in the microorganism's world might be a general route for the passage in the pathogenicity to ensure their survival under nutrient limitation conditions. PMID:21611776

  8. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improves stool frequency pursuant to Article 13(5 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2013-02-01

    Full Text Available Following an application from PiLeJe submitted for authorisation of a health claim pursuant to Article 13(5 of Regulation (EC No 1924/2006 via the Competent Authority of France, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improves stools frequency. The food that is the subject of the health claim is a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104. The information provided was insufficient to establish that the strain L. lactis LA 103 was sufficiently characterised. The Panel considers that if in a combination of several microorganisms and/or ingredients one microorganism or ingredient used in the combination is not sufficiently characterised, then the combination is considered to be not sufficiently characterised. A combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103, and S. thermophilus LA 104 is not sufficiently characterised. The Panel concludes that a cause and effect relationship cannot be established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104 and improves stool frequency.

  9. Thermorudis pharmacophila sp. nov., a novel member of the class Thermomicrobia isolated from geothermal soil, and emended descriptions of Thermomicrobium roseum, Thermomicrobium carboxidum, Thermorudis peleae and Sphaerobacter thermophilus.

    Science.gov (United States)

    Houghton, Karen M; Morgan, Xochitl C; Lagutin, Kirill; MacKenzie, Andrew D; Vyssotskii, Mikhail; Mitchell, Kevin A; McDonald, Ian R; Morgan, Hugh W; Power, Jean F; Moreau, John W; Hanssen, Eric; Stott, Matthew B

    2015-12-01

    An aerobic, thermophilic and cellulolytic bacterium, designated strain WKT50.2T, was isolated from geothermal soil at Waikite, New Zealand. Strain WKT50.2T grew at 53-76 °C and at pH 5.9-8.2. The DNA G+C content was 58.4 mol%. The major fatty acids were 12-methyl C18 : 0 and C18 : 0. Polar lipids were all linked to long-chain 1,2-diols, and comprised 2-acylalkyldiol-1-O-phosphoinositol (diolPI), 2-acylalkyldiol-1-O-phosphoacylmannoside (diolP-acylMan), 2-acylalkyldiol-1-O-phosphoinositol acylmannoside (diolPI-acylMan) and 2-acylalkyldiol-1-O-phosphoinositol mannoside (diolPI-Man). Strain WKT50.2T utilized a range of cellulosic substrates, alcohols and organic acids for growth, but was unable to utilize monosaccharides. Robust growth of WKT50.2T was observed on protein derivatives. WKT50.2T was sensitive to ampicillin, chloramphenicol, kanamycin, neomycin, polymyxin B, streptomycin and vancomycin. Metronidazole, lasalocid A and trimethoprim stimulated growth. Phylogenetic analysis of 16S rRNA gene sequences showed that WKT50.2T belonged to the class Thermomicrobia within the phylum Chloroflexi, and was most closely related to Thermorudis peleae KI4T (99.6% similarity). DNA-DNA hybridization between WKT50.2T and Thermorudis peleae DSM 27169T was 18.0%. Physiological and biochemical tests confirmed the phenotypic and genotypic differentiation of strain WKT50.2T from Thermorudis peleae KI4T and other members of the Thermomicrobia. On the basis of its phylogenetic position and phenotypic characteristics, we propose that strain WKT50.2T represents a novel species, for which the name Thermorudis pharmacophila sp. nov. is proposed, with the type strain WKT50.2T ( = DSM 26011T = ICMP 20042T). Emended descriptions of Thermomicrobium roseum, Thermomicrobium carboxidum, Thermorudis peleae and Sphaerobacter thermophilus are also proposed, and include the description of a novel respiratory quinone, MK-8 2,3-epoxide (23%), in Thermomicrobium roseum. PMID

  10. Effect of the addition of phytosterols and tocopherols on Streptococcus thermophilus robustness during industrial manufacture and ripening of a functional cheese as evaluated by qPCR and RT-qPCR.

    Science.gov (United States)

    Pega, J; Rizzo, S; Pérez, C D; Rossetti, L; Díaz, G; Ruzal, S M; Nanni, M; Descalzo, A M

    2016-09-01

    The quality of functional food products designed for the prevention of degenerative diseases can be affected by the incorporation of bioactive compounds. In many types of cheese, the performance of starter microorganisms is critical for optimal elaboration and for providing potential probiotic benefits. Phytosterols are plant lipophilic triterpenes that have been used for the design of functional dairy products because of their ability to lower serum cholesterol levels in humans. However, their effect on the starter culture behavior during cheesemaking has not yet been studied. Here, we followed DNA and RNA kinetics of the bacterium Streptococcus thermophilus, an extensively used dairy starter with probiotic potential, during industrial production of a functional, semi-soft, reduced-fat cheese containing phytosterol esters and alpha-tocopherol as bioactive compounds. For this purpose, real-time quantitative PCR (qPCR) and reverse transcription-qPCR (RT-qPCR) assays were optimized and applied to samples obtained during the manufacture and ripening of functional and control cheeses. An experimental set-up was used to evaluate the detection threshold of free nucleic acids for extraction protocols based on pelleted microorganisms. To our knowledge, this straight-forward approach provides the first experimental evidence indicating that DNA is not a reliable marker of cell integrity, whereas RNA may constitute a more accurate molecular signature to estimate both bacterial viability and metabolic activity. Compositional analysis revealed that the bioactive molecules were effectively incorporated into the cheese matrix, at levels considered optimal to exert their biological action. The starter S. thermophilus was detected by qPCR and RT-qPCR during cheese production at the industrial level, from at least 30min after its inoculation until 81days of ripening, supporting the possible role of this species in shaping organoleptic profiles. We also showed for the first time that

  11. Adesão de linhagem selvagem de Streptococcus thermophilus em superfície de aço inoxidável e efeitos da higienização na sua remoção

    Directory of Open Access Journals (Sweden)

    GÂNDARA Ana Lourdes Neves

    2000-01-01

    Full Text Available Linhagem selvagem de Streptococcus thermophilus isolada de leite pasteurizado foi avaliada em modelo experimental quanto a adesão em superfície de aço inoxidável e comportamento frente à limpeza e sanificação. Em leite, a adesão do microrganismo em aço inoxidável foi estudada em 6h de contato a 45°C sob agitação e uma higienização com detergentes alcalino e ácido seguida de sanificação foi utilizada para avaliação do comportamento das células aderidas frente à higienização. Esse microrganismo aderiu a essa superfície produzindo uma carga de 10(4UFC/cm². Após a limpeza alcalina não foram detectadas células aderidas; em seguida a limpeza ácida 6 UFC/cm² ainda foram detectadas. A sanificação com hipoclorito de sódio, após a limpeza, foi suficiente para reduzir a carga de S. thermophilus selvagem aderida ao aço inoxidável. O modelo experimental mostrou-se adequado para o estudo, indicando que a cultura selvagem de Streptococcus thermophilus é produtora de biofilme em superfície de aço inoxidável. A limpeza da superfície de aço inoxidável por detergência alcalina remove mais que 99,9% das células aderidas. Pequenos números de células remanescentes são removidos na detergência ácida o que demonstra a necessidade das diferentes etapas e tipos de detergentes para a eficiência da limpeza. Melhores resultados na remoção desse biofilme são alcançadas com detergência alcalina seguida de detergência ácida e mais eficientemente quando se utiliza uma sanificação complementar com hipoclorito de sódio.

  12. Adesão de linhagem selvagem de Streptococcus thermophilus em superfície de aço inoxidável e efeitos da higienização na sua remoção

    OpenAIRE

    Ana Lourdes Neves GÂNDARA; OLIVEIRA José Sátiro de

    2000-01-01

    Linhagem selvagem de Streptococcus thermophilus isolada de leite pasteurizado foi avaliada em modelo experimental quanto a adesão em superfície de aço inoxidável e comportamento frente à limpeza e sanificação. Em leite, a adesão do microrganismo em aço inoxidável foi estudada em 6h de contato a 45°C sob agitação e uma higienização com detergentes alcalino e ácido seguida de sanificação foi utilizada para avaliação do comportamento das células aderidas frente à higienização. Esse microrganismo...

  13. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to a combination of Lactobacillus acidophilus BCCM/LMG P-18806, Lactobacillus delbrueckii BCCM/LMG P-18805 and Streptococcus thermophilus BCCM/LMG P-18807 and reduction

    DEFF Research Database (Denmark)

    Tetens, Inge

    Lactobacillus acidophilus BCCM/LMG P-18806, Lactobacillus delbrueckii BCCM/LMG P-18805 and Streptococcus thermophilus BCCM/LMG P-18807 and reduction of gastro-intestinal discomfort, decreasing potentially pathogenic gastro-intestinal microorganisms, improved lactose digestion, and reduction in numbers of...... circulating CD34+ cells. The food constituent that is the subject of the health claim, a combination of L. acidophilus BCCM/LMG P-18806, L. delbrueckii BCCM/LMG P-18805 and S. thermophilus BCCM/LMG P-18807, is sufficiently characterised. The evidence provided did not establish that the proposed claimed effect......, reduction in numbers of circulating CD34+ cells, is a beneficial physiological effect. The claimed effect, reduction of gastro-intestinal discomfort, is a beneficial physiological effect for the general population. The claimed effect, a decrease in potentially pathogenic gastro-intestinal microorganisms...

  14. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort pursuant to Article 13(5 of Regulation (EC No 1924/2006

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA

    2014-05-01

    Full Text Available Following an application from PiLeJe, submitted pursuant to Article 13(5 of Regulation (EC No 1924/2006 via the Competent Authority of France, the Panel on Dietetic Products, Nutrition and Allergies (NDA was asked to deliver an opinion on the scientific substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and reducing intestinal discomfort. The food that is the subject of the health claim is a combination of four bacterial strains—B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104. The Panel considers that the food, a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104, which is the subject of the health claim is sufficiently characterised. The claimed effect proposed by the applicant is "improves intestinal comfort". The Panel considers that reduction of gastro-intestinal discomfort is a beneficial physiological effect. The Panel considers that the only human study provided for the substantiation of the claim (with limitations did not find an effect of a combination of the bacterial strains being the subject of the claim on gastrointestinal discomfort. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104 and reducing gastro-intestinal discomfort.

  15. 益生菌Lactobacillus plantarum P8与Streptococcus thermophilus混合发酵对发酵乳品质的影响%Effect of probiotic Lactobacillus plantarum P8 and Streptococcus thermophilus on the quality of fermented milk

    Institute of Scientific and Technical Information of China (English)

    何秋雯; 王水泉; 鲍雅静; 礼贺; 王记成; 张和平; 陈卫

    2012-01-01

    将益生菌Lactobacillus plantarum P8以不同接种比例分别与Streptococcus thermophilus ND03、ND05和ND07复配发酵牛乳,并以S.thermophilus单菌发酵为对照.于0h、发酵结束(pH=4.5)及4℃冷藏24 h,分别测定发酵乳样品的发酵时间,及pH值、黏度、脱水收缩率和活菌数并进行感官鉴评.结果表明,L.plantarum P8与S.thermophilus ND03复配,发酵时间显著高于其他组,各组样品黏度和脱水收缩率差异不显著;L.plantarum P8与S.thermophilus ND05分别以5×106 mL-1接种1∶1复配时,样品中L.plantarum P8的活菌数为5.26×107mL-1,酸度适宜,无乳清析出,有良好的黏度,产品风味较好,将该组合应用于发酵乳生产,较可行.%L. plantarutn P8 was mixed respectively with S. thermophillus ND03, ND05 and ND07 with different proportion for bovine milk fermentation with single S. thermophillus fermented milk as the control. At the baseline (0 h), the end of fermentation (pH=4.5) and storage (4℃ for 24 h) fermentation time, pH, viscosity, syneresis, and sensory characteristics of yogurts as well as the bacterial viable counts were evaluated. The results indicated that fermention time of milk fermented by combined L. plantarum P8 and S. thermophilus ND03 was significantly longer than other groups(P<0.05=,while viscosity and syneresis had no significant differences(P>0.05). Moreover, the fermented milk showed great quality with fine viscosity, moderate acidity, no whey separating, good spinnablility and nice flavor while combined L. plantarum P8 and S. thermophilus ND05 with 1:1 ratio(5×l06 mL-1 each) for fermentation, suggesting that this combination could be applied for yoghurt production.

  16. Optimize culture conditions of streptococcus thermophilus for fermentation producing nisin by response surface methodology%响应面法优化 Nisin 发酵的培养条件

    Institute of Scientific and Technical Information of China (English)

    贺小贤; 郑茂奎; 刘欢; 彭光杰

    2014-01-01

    In order to improve fermentation titer unit of Nisin ,the MRS was used as the fer‐mentation medium by streptococcus thermophilus and titer unit of Nisin to Staphylococcus aureus which is used as indicator bacteria serve as detection index of titer unit of Nisin .On the basis of single factor experiment ,optimization of fermentation initial pH ,inoculation a‐mount of Streptococcus thermophilus and corn steep liquor content for producing Nisin by u‐sing response surface analysis methodology .The experiment results showed that the optimal fermentation condition was initial pH 6 .60 ,inoculation amount of 4 .80% and corn steep liq‐uor content of 25 .60% ,and corn steep liquor content is the maximum factor for affecting the fermentation titer unit of Nisin and inoculation is the minimal factor .Under these conditions , the Nisin titer unit was increased by 18 .07% and reached up to 1 602 .77 ± 6 .38 IU/mL which is consistent with the predicted value .These show that it is effective for optimizing culture conditions of Nisin by response surface methodology .%为了提高嗜热乳链球菌发酵生产Nisin的效价,以M RS为发酵培养基,以金黄色葡萄球菌为效价检测指示菌,以Nisin效价为考察指标,在单因素实验的基础上,采用响应面分析法优化发酵初始pH、接种量以及玉米浆添加量.结果表明影响Nisin效价的最大因素是玉米浆添加量,其次是发酵初始p H ,接种量影响最小.最佳初始p H6.60,接种量4.80%,玉米浆添加量2560%,在此条件下 Nisin 的效价可达1602.77±6.38 IU/mL ,较优化前提高了18.07%,其实验结果与模型预测值拟合良好,说明通过响应面试验设计对Nisin发酵条件的优化是有效的.

  17. An example of non-conservation of oligomeric structure in prokaryotic aminoacyl-tRNA synthetases. Biochemical and structural properties of glycyl-tRNA synthetase from Thermus thermophilus.

    Science.gov (United States)

    Mazauric, M H; Reinbolt, J; Lorber, B; Ebel, C; Keith, G; Giegé, R; Kern, D

    1996-11-01

    Glycyl-tRNA synthetase (Gly-tRNA synthetase) from Thermus thermophilus was purified to homogeneity and with high yield using a five-step purification procedure in amounts sufficient to solve its crystallographic structure [Logan, D.T., Mazauric, M.-H., Kern, D. & Moras, D. (1995) EMBO J. 14, 4156-4167]. Molecular-mass determinations of the native and denatured protein indicate an oligomeric structure of the alpha 2 type consistent with that found for eukaryotic Gly-tRNA synthetases (yeast and Bombyx mori), but different from that of Gly-tRNA synthetases from mesophilic prokaryotes (Escherichia coli and Bacillus brevis) which are alpha 2 beta 2 tetramers. N-terminal sequencing of the polypeptide chain reveals significant identity, reaching 50% with those of the eukaryotic enzymes (B. mori, Homo sapiens, yeast and Caenorhabditis elegans) but no significant identity was found with both alpha and beta chains of the prokaryotic enzymes (E. coli, Haemophilus influenzae and Coxiella burnetii) albeit the enzyme is deprived of the N-terminal extension characterizing eukaryotic synthetases. Thus, the thermophilic Gly-tRNA synthetase combines strong structural homologies of eukaryotic Gly-tRNA synthetases with a feature of prokaryotic synthetases. Heat-stability measurements show that this synthetase keeps its ATP-PPi exchange and aminoacylation activities up to 70 degrees C. Glycyladenylate strongly protects the enzyme against thermal inactivation at higher temperatures. Unexpectedly, tRNA(Gly) does not induce protection. Cross-aminoacylations reveal that the thermophilic Gly-tRNA synthetase charges heterologous E. coli tRNA(gly(GCC)) and tRNA(Gly(GCC)) and yeast tRNA(Gly(GCC)) as efficiently as T. thermophilus tRNA(Gly). All these aminoacylation reactions are characterized by similar activation energies as deduced from Arrhenius plots. Therefore, contrary to the E. coli and H. sapiens Gly-tRNA synthetases, the prokaryotic thermophilic enzyme does not possess a strict

  18. Dicty_cDB: Contig-U06996-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 8 AY142891_1( AY142891 |pid:none) Heliobacillus mobilis Dephospho-Co... 93 6e-18 FN392322_502( FN392322 |pid...1034 |pid:none) Natranaerobius thermophilus JW/... 92 1e-17 CP000474_1981( CP000474 |pid:none) Arthrobacter ... CP000088 |pid:none) Thermobifida fusca YX, complete... 86 7e-16 (Q38VS6) RecName: Full=Dephospho-CoA kinase...roxidans MPO... 55 1e-06 AM942759_2031( AM942759 |pid:none) Proteus mirabilis strain HI4320... 55 1e-06 (Q5N.....................done Score E Sequences producing significant alignments: (bits) Value N ( AU269735 ) Dictyosteli

  19. Dicty_cDB: Contig-U10434-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ochondrial-processing peptidase subuni... 80 3e-14 AE008692_1890( AE008692 |pid:none) Zymomonas mobilis subsp. mobili...e-23 AL591785_132( AL591785 |pid:none) Sinorhizobium meliloti 1021 comp... 110 3e-23 CP000463_4718( CP000463...37( CP001034 |pid:none) Natranaerobius thermophilus JW/... 106 4e-22 CP000908_3211( CP000908 |pid:none) Methylob...8_783( CP000088 |pid:none) Thermobifida fusca YX, complete ... 93 6e-18 CP000766_320( CP000766 |pid:none) Ri...e MTYFT1G-... 90 4e-17 CP000117_2333( CP000117 |pid:none) Anabaena variabilis ATC

  20. Dicty_cDB: Contig-U16390-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 38 1.8 CP001034_767( CP001034 |pid:none) Natranaerobius thermophilus JW/N... 38 2.3 CP000686_2932( CP000686 |pid:none) Roseiflex... 0.00 m3a: 0.00 m3b: 0.00 m_ : 1.00 40.0 %: extracellular, including cell wall 16.0 %: cytoplasmic 12.0 %: mitochon...te s... 46 7.1 1 ( AP008207 ) Oryza sativa (japonica cultivar-group) genomic DN... 46 7.1 1 ( AP0...s: 59344 Number of successful extensions: 6416 Number of sequences better than 10.0: 198 length of query: 2794 le...e:ddv43d20, 3' ... 198 8e-46 1 ( AC176379 ) Strongylocentrotus purpuratus clon

  1. Preparation of Gamma-Aminobutyric Acid Using Streptococcus salivarius subsp.thermophilus Y-2 Cells%唾液链球菌嗜热亚种Y-2细胞转化法制备γ-氨基丁酸

    Institute of Scientific and Technical Information of China (English)

    杨胜远; 陆兆新; 吕凤霞; 别小妹

    2011-01-01

    研究反应pH值、反应温度、重金属盐、表面活性剂、底物浓度、菌体质最浓度和磷酸吡哆醛添加量对Streptococcus salivarius subsp.thermophilus Y-2细胞转化法生产γ-氨基丁酸的影响.获得反应体系的最佳组成为:湿菌体25g/L、BaCl2 40mmol/L、Triton X-100体积分数0.02%、L-谷氨酸单钠盐(L-monosodium glutamate,MSG)47.5g/L和L-谷氨酸(L-glutamic acid,L-Glu)90.0g/L.该体系在40℃、pH4.5和搅拌速度100r/min的最适转化条件下进行反应72h,转化液GABA产量达到了(87.16±4.33)g/L,细胞平均生产力为(48.42±2.41)mg/(h·g),摩尔转化率为(97.60±4.71)%.

  2. Obtención de ácido láctico por fermentación de almidón de ñame espino mediante el Lactobacillus delbrueckii ssp. bulgaricus y el Streptococcus thermophilus para su uso en la producción de ácido poliláctico

    OpenAIRE

    Tejada Tovar, Ronald Eduardo

    2015-01-01

    Resumen: El propósito del presente trabajo fue evaluar la producción de ácido láctico obtenido por la fermentación del almidón de ñame espino Discorea rotundata mediante la acción de la mezcla de Lactobacillus delbrueckii ssp. bulgaricus y el Streptococcus thermophilus, para su posible uso en la obtención de APL; estableciendo el proceso de obtención y caracterizando el producto obtenido mediante análisis de sus propiedades fisicoquímicas y funcionales; a este se le realizó un seguimiento med...

  3. Overexpression of a novel thermostable and chloride-tolerant laccase from Thermus thermophilus SG0.5JP17-16 in Pichia pastoris and its application in synthetic dye decolorization.

    Directory of Open Access Journals (Sweden)

    Huiping Liu

    Full Text Available Laccases have been used for the decolorization and detoxification of synthetic dyes due to their ability to oxidize a wide variety of dyes with water as the sole byproduct. A putative laccase gene (LacTT from Thermus thermophilus SG0.5JP17-16 was screened using the genome mining approach, and it was highly expressed in Pichia pastoris, yielding a high laccase activity of 6130 U/L in a 10-L fermentor. The LacTT open reading frame encoded a protein of 466 amino acid residues with four putative Cu-binding regions. The optimal pH of the recombinant LacTT was 4.5, 6.0, 7.5 and 8.0 with 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonic acid (ABTS, syringaldazine (SGZ, guaiacol, and 2,6-dimethoxyphenol (2,6-DMP as the substrate, respectively. The optimal temperature of LacTT was 90°C with guaiacol as the substrate. LacTT was highly stable at pH 4.0-11.0 and thermostable at 40°C-90°C, confirming that it is a pH-stable and thermostable laccase. Furthermore, LacTT also exhibited high tolerance to halides such as NaCl, NaBr and NaF, and decolorized 100%, 94%, 94% and 73% of Congo Red, Reactive Black B and Reactive Black WNN, and Remazol Brilliant Blue R, respectively. Interestingly, addition of high concentration of NaCl increased the RBBR decolorization efficiency of LacTT. These results suggest that LacTT is a good candidate for industrial applications such as dyestuff processing and degradation of dyes in textile wastewaters.

  4. 固定化唾液链球菌生产γ-氨基丁酸的研究%PRUDUCTION OF γ-AMINOBUTYRIC ACID BY IMMOBILIZED Streptococcus salivarius subsp.thermophilus Y-2

    Institute of Scientific and Technical Information of China (English)

    焦阳; 汪建敏; 杨胜远; 周利娟; 姚正颖; 吕凤霞; 邹晓葵; 陆兆新

    2009-01-01

    以唾液链球茵嗜热亚种(Streptococcus salivarius subsp.thermophilus Y-2)为供试菌株,考察了卡拉胶、明胶和海藻酸钙等材料将此菌株固定化的效果,并通过比较固定化细胞的谷氨酸脱羧酶(glutamatedecarboxylase,GAD)活性及γ-氨基丁酸的产量和载体机械强度,确定了海藻酸钙作为固定化细胞的适宜载体.优化后得到的最适固定化条件(W/V)为:海藻酸钠2%,CaCl_2 14%,茵体25%,凝胶平均颗粒直径1.64 mm,在此条件下测得固定化细胞的GAD活性为游离细胞的1.2倍.细胞多批次应用稳定性试验证明:固定化细胞较游离细胞有着更稳定的GAD活性,反复使用60 h后,固定化细胞GAD活性仍能保持其初始活性的90%以上,γ-氨基丁酸的积累量达到7.97 g/L.

  5. All the O2 Consumed by Thermus thermophilus Cytochrome ba3 Is Delivered to the Active Site through a Long, Open Hydrophobic Tunnel with Entrances within the Lipid Bilayer.

    Science.gov (United States)

    Mahinthichaichan, Paween; Gennis, Robert B; Tajkhorshid, Emad

    2016-03-01

    Cytochrome ba3 is a proton-pumping heme-copper oxygen reductase from the extreme thermophile Thermus thermophilus. Despite the fact that the enzyme's active site is buried deep within the protein, the apparent second order rate constant for the initial binding of O2 to the active-site heme has been experimentally found to be 10(9) M(-1) s(-1) at 298 K, at or near the diffusion limit, and 2 orders of magnitude faster than for O2 binding to myoglobin. To provide quantitative and microscopic descriptions of the O2 delivery pathway and mechanism in cytochrome ba3, extensive molecular dynamics simulations of the enzyme in its membrane-embedded form have been performed, including different protocols of explicit ligand sampling (flooding) simulations with O2, implicit ligand sampling analysis, and in silico mutagenesis. The results show that O2 diffuses to the active site exclusively via a Y-shaped hydrophobic tunnel with two 25-Å long membrane-accessible branches that coincide with the pathway previously suggested by the crystallographically identified xenon binding sites. The two entrances of the bifurcated tunnel of cytochrome ba3 are located within the lipid bilayer, where O2 is preferentially partitioned from the aqueous phase. The largest barrier to O2 migration within the tunnel is estimated to be only 1.5 kcal/mol, allowing O2 to reach the enzyme active site virtually impeded by one-dimensional diffusion once it reaches a tunnel entrance at the protein surface. Unlike other O2-utilizing proteins, the tunnel is "open" with no transient barriers observed due to protein dynamics. This unique low-barrier passage through the protein ensures that O2 transit through the protein is never rate-limiting. PMID:26845082

  6. Effect of ABF Bio + malt extract on the growth of Streptococcus thermophilus%双麦麦精对嗜热链球菌生长影响的研究

    Institute of Scientific and Technical Information of China (English)

    赵爽; 刘少伟; 陈如琪; 吕宝龙; 卢艳花; 费楠

    2012-01-01

    主要研究双麦麦精对嗜热链球菌生长过程的影响。通过在营养成分缺省的培养基中添加双麦麦精,采用分光光度法测定菌液吸光值(OD600),根据OD值确定对应的嗜热链球菌的活菌数,从而分析双麦麦精对嗜热链球菌生长情况的影响。利用正交实验,通过直接计数法确定双麦麦精与其他营养成分的最佳比例。结果表明,双麦麦精对嗜热链球菌的生长有明显的促进作用,可为嗜热链球菌提供充足的碳源和生长因子。双麦麦精的添加量为16g/L时效果最佳。分析比较吸光值法和直接计数法测得的生长曲线,结果表明两种方法具有良好的相似性,其中在对数期有强相关性。%The effects of ABF Bio + malt extract on the main nutrition constituent of the Streptococcus thermophiles in its growth progress by adding ABF Bio + malt in the incomplete nutrient medium were studied.The number of viable cells in Streptococcus thermophiles counted according to its Bacilli absorbance was used to analyse the effect on Streptococcus thermophiles brought by ABF Bio + malt extract.The optimal proportion of ABF Bio + malt extract and other nutrients was determined by orthogonal experiment with direct counting method.The results showed that ABF Bio + malt extract played an important role of the augmentor the growth of streptococcus thermophilus as well as a provider of sufficient carbon source and growth factors for it.The ABF Bio + malt extract produced the best result when its additive amount reached 16g/L.After analysis and comparison of the growth curves which were measured by absorb value method and the direct counting method respectively, the curves were proved to be of good similarity, especially in the logarithmic phase.

  7. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014. Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and

    DEFF Research Database (Denmark)

    Tetens, Inge

    to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improvement of bowel function by increasing stool frequency. The food that is the subject of the health claim is a combination of four bacterial...... effect proposed by the applicant is "improves stool frequency". The Panel considers that improvement of bowel function by increasing stool frequency, provided that it does not result in diarrhoea, is a beneficial physiological effect. The Panel considers that the human study provided for the...... substantiation of the claim did not find an increase in stool frequency following consumption of a combination of the bacterial strains which is the subject of the claim. The Panel concludes that a cause and effect relationship has not been established between the consumption of a combination of B. longum LA 101...

  8. Purification and Structural Characterization of Exopolysaccharide Produced by Streptococcus thermophilus CH9%嗜热链球菌CH9胞外多糖的分离纯化及结构分析

    Institute of Scientific and Technical Information of China (English)

    张新源; 刘会平; 曹春玲; 季玲

    2012-01-01

    Crude exopolysaccharides (EPS) isolated from the fermentation supernatant of Streptococcus thermophilus CH9 were fractionated by DEAE-52 column chromatography into EPS1, EPS2 and EPS3. Sephadex G-100 column chromatography was used to further ffactionate the three factions to harvest their respective major components named as EPSla, EPS2a and EPS3a, respectively. EPSla was a neutral polysaccharide with a molecular weight of 1.8×10^6 U, and EPS2a and EPS3a were acidic polysaccharides with a molecular weight of 1.06×10^6u and 1.05 × 10^6 u, respectively. Agarose gel electrophoresis analysis indicated that all these three polysaccharides consisted of a single component. UV and IR spectroscopic analyses showed that all of them had characteristic adsorption peaks of polysaccharide. EPS2a and EPS3a might be polysaccharide- protein complexes. Congo red test revealed that EPSla rather than EPS2a and EPS3a had a three-stranded helix structure. Beta elimination test demonstrated that EPS la and EPS3a were -O-linked, but EPS2a was a -N-linked polysaccharide.%对嗜热链球菌CH9胞外多糖进行分离纯化,经DEAE-52离子交换柱及SephadexG-100凝胶柱得到单一组分,利用高效液相色谱(HPLC)测其分子质量,结果表明:EPSla为中性多糖,分子质量为1.8×10^6u;EPS2a、EPS3a为酸性多糖,分子质量分别为1.06×10^6、1.05X10^u。经琼脂糖凝胶电泳)及SephadexG-100凝胶柱鉴定3种糖均为单一组分。紫外及红外光谱扫描结果显示:3种糖均具有多糖的特征吸收峰,且EPS2a、EPS3a可能为糖与蛋白的复合物。刚果红实验表明:EPSla具有三股螺旋结构,而其他两种糖并未发现此现象。卢消去实验证明:EPSla、EPS3a为—O-连接,EPS2a为-N-连接。

  9. Effects of inoculum ratios of Lactobacillus delbrueckii subsp.bulgaricus and Streptococcus thermophilus on the quality of probiotic fermented milk by Bifidobacterium lactis%Lactobacillus delbrueckii subsp.bulgaricus和Streptococcus thermophilus接种比例对Bifidobacterium lactis益生菌发酵乳品质的影响

    Institute of Scientific and Technical Information of China (English)

    李慧; 白梅; 王记成; 魏爱彬; 孔亚楠; 张和平; 孙天松

    2012-01-01

    Different ratios (1:1, 1:10, 1:100, 1:1000) of Lactobacillus delbnteckii subsp. Bulgaricus ND02 (LB-ND02) and Streptococcus thermophilus ND03 (ST-ND03) plus with Bifidobacterium lactis V9 (B. Lactis V9, 2.0X107 g"1) were used as starter cultures for milk fermentation. Some indexs of prepared probiotic fermented milk were determined for evaluation for effect of different ratios of inoculum on the quality of probiotic fermented milk during the fermentation and storage. The results showed the fermentation time was significandy prolonged, viable numbers of B. Lactis V9 was significantly increased .After the fermentation followed by a 28 d storage, the survival of B. Lactis V9 were significandy different and the postacidifition was weakened as the ratio of LB-ND02 decreased. . It is suggested that different ratios of LB-ND02 and ST-ND03 significandy influence the fermentation time, viable numbers of B. Lactis V9, postacidifition and visicosity during the fermentation and storage.%将Lactobacillus delbrueckii subsp.bulgaricus ND02(LB-ND02)和Streptococcus thermophilus ND03(ST-ND03)按1∶1、1∶10、1∶100、1∶1000接种于脱脂乳中,同时接入益生菌Bifidobacterium lactis V9(B.lactis V9,接种量为2.0×107 g-1),于42℃进行发酵.通过对发酵及贮藏过程中发酵乳指标的测定,评价LB-ND02和ST-ND03的接种比例对发酵乳品质的影响.结果表明,随着LB-ND02接种比例减小,凝乳时间显著延长,B.lactis V9活菌数显著提高.4 ℃贮藏28 d后,随LB-ND02接种比例减小,B.lactis V9存活率差异显著,后酸化也显著减弱.研究发现,LB-ND02和ST-ND03的接种比例,显著影响发酵乳的发酵时间、B.lactis V9活菌数、后酸化及黏度.

  10. 唾液链球菌嗜热亚种Y-2产谷氨酸脱羧酶的影响因子确立%Ascertainment of Factors Affecting Glutamate Decarboxylase Production by Streptococcus Salivarius ssp.thermophilus Y-2

    Institute of Scientific and Technical Information of China (English)

    杨胜远; 陆兆新; 余勃; 林谦; 焦阳; 别小妹; 吕凤霞

    2008-01-01

    从产酶和细胞生长较好的MRS培养基出发,对Streptococcus salivarius ssp.thermophilus Y-2产谷氨酸脱羧酶(glutamate decarboxylase,GAD)的影响因子进行探讨,结果当培养基组成和培养条件为蛋白胨15g/L、牛肉膏12.5g/L、蔗糖12.5g/L、柠檬酸二铵2.0g/L、乙酸钠5.0g/L、K2HPO4 2.0g/L、CaCl2 2.0 g/L、Tween 80 1.0ml、pH7.0、接种量2%(V/V)、发酵温度37℃、发酵时间12h时,较有利于菌株Y-2产GAD.Plackett-Burman设计法研究表明培养基初始pH值和K2HPO4为影响菌株Y-2产GAD的主要影响因素.经对菌株Y-2产GAD影响因素的筛选,新获得的培养基在组成上与MRS培养基相比已发生显著变化,GAD活力提高了1.3倍.

  11. Identification of PHA loci in Thermus thermophilus HB8 genome

    OpenAIRE

    Papi, R. M.; Mimikakou, G. E.; A. A. Pantazaki; Kyriakidis, D A

    2008-01-01

    Abstract Poster Presentation Journal URL: http://www3.interscience.wiley.com/journal/119877016/tocgroup Polyhydroxyalkanoic acids (PHAs) are carbon and energy storage polymers synthesized by most eubacteria and archea in response to environmental conditions. The PHA biosynthetic bacteria are classified into four groups based on the organization of the pha gene locus and the structure-function properties of the PHA synthases. Synthases are the key enzymes in the biosynthesis of PHA and c...

  12. Identificazione, caratterizzazione ed industrializzazione di ceppi di Streptococcus thermophilus per la produzione di yogurt

    OpenAIRE

    D'Alonges, Sara

    2013-01-01

    Il contesto globale del comparto agro-alimentare richiede ad oggi una ricerca continua per assicurare qualità e sicurezza degli alimenti. La produzione moderna di alimenti richiede elevato grado di standardizzazione, particolarmente la produzione gli alimenti fermentati che include un processo biotecnologico in cui la componente biotica gioca un ruolo fondamentale Di qui la necessità disporre di un’ampia gamma di microrganismi atti alla conduzione del processo fermentativo in modo da im...

  13. Expression and Characterization of Hyperthermostable Exo-polygalacturonase TtGH28 from Thermotoga thermophilus.

    Science.gov (United States)

    Wagschal, Kurt; Rose Stoller, J; Chan, Victor J; Lee, Charles C; Grigorescu, Arabela A; Jordan, Douglas B

    2016-07-01

    D-galacturonic acid is a potential platform chemical comprising the principal component of pectin in the citrus processing waste stream. Several enzyme activities are required for the enzymatic production of galacturonic acid from pectin, including exo- and endo-polygalacturonases. The gene TtGH28 encoding a putative GH28 polygalacturonase from Pseudothermotoga thermarum DSM 5069 (Theth_0397, NCBI# AEH50492.1) was synthesized, expressed in Escherichia coli, and characterized. Alignment of the amino acid sequence of gene product TtGH28 with other GH28 proteins whose structures and details of their catalytic mechanism have been elucidated shows that three catalytic Asp residues and several other key active site residues are strictly conserved. Purified TtGH28 was dimeric and hyperthermostable, with K t (0.5)  = 86.3 °C. Kinetic parameters for activity on digalacturonic acid, trigalacturonic acid, and polygalacturonic acid were obtained. No substrate inhibition was observed for polygalacturonate, while the K si values for the oligogalacturonides were in the low mM range, and K i for product galacturonic acid was in the low μM range. Kinetic modeling of the progress of reaction showed that the enzyme is both fully exo- and fully non-processional. PMID:27209035

  14. Probiotic Leuconostoc mesenteroides ssp. cremoris and Streptococcus thermophilus induce IL-12 and IFN-γ production

    OpenAIRE

    Kekkonen, Riina A; Kajasto, Elina; Miettinen, Minja; Veckman, Ville; Korpela, Riitta; Julkunen, Ilkka

    2008-01-01

    AIM: To investigate the capacity of potentially probiotic strains from six bacterial genera to induce cytokine production alone or in combinations in order to identify potential enhancing or synergistic effects in order to select probiotic bacteria for in vivo purposes.

  15. A novel consortium of Lactobacillus rhamnosus and Streptococcus thermophilus for increased access to functional fermented foods

    OpenAIRE

    Kort, Remco; Westerik, Nieke; Mariela Serrano, L.; Douillard, François P.; Gottstein, Willi; Mukisa, Ivan M.; Tuijn, Coosje J.; Basten, Lisa; Hafkamp, Bert; Meijer, Wilco C.; Teusink, Bas; Vos, de, W.M.; Reid, Gregor; Sybesma, Wilbert

    2015-01-01

    Background The lactic acid bacterium Lactobacillus rhamnosus GG is the most studied probiotic bacterium with proven health benefits upon oral intake, including the alleviation of diarrhea. The mission of the Yoba for Life foundation is to provide impoverished communities in Africa increased access to Lactobacillus rhamnosus GG under the name Lactobacillus rhamnosus yoba 2012, world’s first generic probiotic strain. We have been able to overcome the strain’s limitations to grow in food matrice...

  16. Sequences spanning the leader-repeat junction mediate CRISPR adaptation to phage in Streptococcus thermophilus

    OpenAIRE

    Wei, Yunzhou; Chesne, Megan T.; Terns, Rebecca M.; Terns, Michael P.

    2015-01-01

    CRISPR-Cas systems are RNA-based immune systems that protect prokaryotes from invaders such as phages and plasmids. In adaptation, the initial phase of the immune response, short foreign DNA fragments are captured and integrated into host CRISPR loci to provide heritable defense against encountered foreign nucleic acids. Each CRISPR contains a ∼100–500 bp leader element that typically includes a transcription promoter, followed by an array of captured ∼35 bp sequences (spacers) sandwiched bet...

  17. Cloning, expression and purification of D-Tyr-tRNATyr-deacylase from Thermus thermophilus

    OpenAIRE

    Rybak M. Yu.; Kovalenko O. P.; Kryklyvyi I. A.; Tukalo M. A.

    2015-01-01

    D-Tyr-tRNATyr-deacylase (DTD) is a conservative enzyme, found in all domains of life, which ensures an additional checkpoint in the recycling of misaminoacylated D-Tyr-tRNATyr. DTD is capable of accelerating the hydrolysis of the ester linkage of D-Tyr-tRNATyr producing a free tRNA and D-tyrosine, thereby preventing an incorrect incorporation of D-amino acids into proteins. Deacylase distinguishes between D- and L-aminoacyl moieties and does not hydrolyze L-aminoacylated tRNA. The structural ...

  18. Detection and transfer of the glutamate decarboxylase gene in Streptococcus thermophilus

    Science.gov (United States)

    GABA (gamma-aminobutyric acid) is generated from glutamate by the action of glutamic acid decarboxylase (GAD) and characterized by hypotensive, diuretic and tranquilizing effects in humans and animals. The production of GABA by lactic acid starter bacteria would enhance the functionality of fermen...

  19. New biotechnological perspectives of a NADH oxidase variant from Thermus thermophilus HB27 as NAD+-recycling enzyme

    Directory of Open Access Journals (Sweden)

    Rocha-Martín Javier

    2011-11-01

    Full Text Available Abstract Background The number of biotransformations that use nicotinamide recycling systems is exponentially growing. For this reason one of the current challenges in biocatalysis is to develop and optimize more simple and efficient cofactor recycling systems. One promising approach to regenerate NAD+ pools is the use of NADH-oxidases that reduce oxygen to hydrogen peroxide while oxidizing NADH to NAD+. This class of enzymes may be applied to asymmetric reduction of prochiral substrates in order to obtain enantiopure compounds. Results The NADH-oxidase (NOX presented here is a flavoenzyme which needs exogenous FAD or FMN to reach its maximum velocity. Interestingly, this enzyme is 6-fold hyperactivated by incubation at high temperatures (80°C under limiting concentrations of flavin cofactor, a change that remains stable even at low temperatures (37°C. The hyperactivated form presented a high specific activity (37.5 U/mg at low temperatures despite isolation from a thermophile source. Immobilization of NOX onto agarose activated with glyoxyl groups yielded the most stable enzyme preparation (6-fold more stable than the hyperactivated soluble enzyme. The immobilized derivative was able to be reactivated under physiological conditions after inactivation by high solvent concentrations. The inactivation/reactivation cycle could be repeated at least three times, recovering full NOX activity in all cases after the reactivation step. This immobilized catalyst is presented as a recycling partner for a thermophile alcohol dehydrogenase in order to perform the kinetic resolution secondary alcohols. Conclusion We have designed, developed and characterized a heterogeneous and robust biocatalyst which has been used as recycling partner in the kinetic resolution of rac-1-phenylethanol. The high stability along with its capability to be reactivated makes this biocatalyst highly re-useable for cofactor recycling in redox biotransformations.

  20. Pulse Radiolysis Studies of Temperature Dependent Electron Transfers among Redox Centers in ba(3)-Cytochrome c Oxidase from Thermus thermophilus

    DEFF Research Database (Denmark)

    Farver, Ole; Wherland, Scot; Antholine, William E;

    2010-01-01

    The functioning of cytochrome c oxidases involves orchestration of long-range electron transfer (ET) events among the four redox active metal centers. We report the temperature dependence of electron transfer from the Cu(A)(r) site to the low-spin heme-(a)b(o) site, i.e., Cu(A)(r) + heme-a(b)(o) ...

  1. Investigation of vital pathogenic target orotate phosphoribosyltransferases (OPRTase) from Thermus thermophilus HB8: Phylogenetic and molecular modeling approach.

    Science.gov (United States)

    Surekha, Kanagarajan; Prabhu, Damodharan; Richard, Mariadasse; Nachiappan, Mutharasappan; Biswal, Jayashree; Jeyakanthan, Jeyaraman

    2016-06-01

    Biosynthesis pathways of pyrimidine and purine are shown to play an important role in regular cellular activities. The biosynthesis can occur either through de novo or salvage pathways based on the requirement of the cell. The pyrimidine biosynthesis pathway has been linked to several disorders and various autoimmune diseases. Orotate phosphoribosyl transferase (OPRTase) is an important enzyme which catalyzes the conversion of orotate to orotate monophosphate in the fifth step of pyrimidine biosynthesis. Phylogenetic analysis of 228 OPRTase sequences shows the distribution of proteins across different living forms of life. High structural similarities between Thermusthermophilus and other organisms kindled us to concentrate on OPRTase as an anti-pathogenic target. In this study, a homology model of OPRTase was constructed using 2P1Z as a template. About 100ns molecular dynamics simulation was performed to investigate the conformational stability and dynamic patterns of the protein. The amino acid residues (Met1, Asp2, Glu43, Ala44, Glu47, Lys51, Ala157 and Leu158) lining in the binding site were predicted using SiteMap. Further, structure based virtual screening was performed on the predicted binding site using ChemBridge, Asinex, Binding, NCI, TosLab and Zinc databases. Compounds retrieved from the screening collections were manually clustered. The resultant protein-ligand complexes were subjected to molecular dynamics simulations, which further validates the binding modes of the hits. The study may provide better insight for designing potent anti-pathogenic agent. PMID:26861612

  2. 12-Fold symmetry of the putative portal protein from the Thermus thermophilus bacteriophage G20C determined by X-ray analysis

    International Nuclear Information System (INIS)

    Crystal data on a putative portal protein from the thermostable bacteriophage G20C indicate that it forms a 12-subunit assembly. In tailed bacteriophages and several animal viruses, the portal protein forms the gateway through which viral DNA is translocated into the head structure during viral particle assembly. In the mature virion the portal protein exists as a dodecamer, while recombinant portal proteins from several phages, including SPP1 and CNPH82, have been shown to form 13-subunit assemblies. A putative portal protein from the thermostable bacteriophage G20C has been cloned, overexpressed and purified. Crystals of the protein diffracted to 2.1 Å resolution and belonged to space group P4212, with unit-cell parameters a = b = 155.3, c = 115.4 Å. The unit-cell content and self-rotation function calculations indicate that the protein forms a circular 12-subunit assembly

  3. Impact of process parameters on the sourdough microbiota, selection of suitable starter strains, and description of the novel yeast Cryptococcus thermophilus sp. nov.

    OpenAIRE

    Vogelmann, Stephanie Anke

    2013-01-01

    The microbiota of a ripe sourdough consists of lactic acid bacteria (LAB), especially of the genus Lactobacillus, and yeasts. Their composition is influenced by the interplay of species or strains, the kind of substrate as well as the process parameters temperature, dough yield, redox potential, refreshment time, and number of propagation steps (Hammes and Gänzle, 1997). As taste and quality of sourdough breads are mainly influenced by the fermentation microbiota, intense research has been fo...

  4. Molecular identification of differentially regulated genes in the hydrothermal-vent species Bathymodiolus thermophilus and Paralvinella pandorae in response to temperature

    OpenAIRE

    Shillito Bruce; Jollivet Didier; Boutet Isabelle; Moraga Dario; Tanguy Arnaud

    2009-01-01

    Abstract Background Hydrothermal vents and cold seeps represent oases of life in the deep-sea environment, but are also characterized by challenging physical and chemical conditions. The effect of temperature fluctuations on vent organisms in their habitat has not been well explored, in particular at a molecular level, most gene expression studies being conducted on coastal marine species. In order to better understand the response of hydrothermal organisms to different temperature regimes, d...

  5. Elektronentransfer zwischen Komplex III und IV der Atmungskette von Paracoccus denitrificans und Thermus thermophilus : funktionelle und kinetische Charakterisierung der Interaktionen anhand von löslichen Fragmenten

    OpenAIRE

    Janzon, Julia

    2007-01-01

    Adenosintriphosphat (ATP) als universelles Energieäquivalent der Zelle wird durch die oxidative Phosphorylierung synthetisiert, bei der Elektronen entlang des elektrochemischen Gefälles der Atmungskette über verschiedene Redoxkomplexe transferiert und durch die chemiosmotische Kopplung Protonen über die Membran gepumpt werden. Der Protonengradient wird dann von der ATP-Synthase genutzt, um ADP zu ATP zu phosphorylieren. Zentraler Redoxkomplex der Atmungskette vieler Pro- und Eukaryonten ist d...

  6. Detection and Homology Analysis of CRISPR in Streptococcus thermophilus%嗜热链球菌中CRISPR序列的检测与同源性分析

    Institute of Scientific and Technical Information of China (English)

    邓凯波; 霍贵成

    2013-01-01

    为探明内蒙古的8株嗜热链球菌的CRISPR,用PCR方法扩增了其CRISPR序列,并采用生物信息学方法分析和预测了重复序列(direct repeat,DR)的同源性及二级结构.结果表明:除S4只含有一个CRISPR结构外,其余7株嗜热链球菌均检测出3条CRISPR序列,远高于CRISPR database公布细菌中具有该结构的比例(46.4%),且分别具特异性的重复序列(DR1~DR3); CRISPR最长达2853bp,最短仅101bp.对DR的二级结构预测发现,DR1~DR3均能形成回文结构,但茎环大小会有差异;在同源性比对中发现,除多数同属或同种外,供试DR还与个别远缘菌种具有高同源性,这种现象证明了供试菌株的CRISPR序列同样存在的水平基因转移,并可能存在其他的进化进程.

  7. Detection of CRSPR-Cas system in Streptococcus thermophilus%嗜热链球菌CRISPR-Cas系统的检测

    Institute of Scientific and Technical Information of China (English)

    李婉; 梁宏彰; 张丹青; 王娜娜; 唐雅茹; 李柏良; 霍贵成

    2016-01-01

    [目的]CRISPR-Cas系统为嗜热链球菌抵抗噬菌体等外源基因元件提供获得性免疫,分析NCBI中已公开发表全基因组序列的9株嗜热链球菌所含CRISPR-Cas系统的数目和类型,对实验室相应菌株的CRISPR-Cas系统进行检测.[方法]利用生物信息学方法对NCBI中9株已测序嗜热链球菌所含CRISPR-Cas系统进行分析,根据其Cas基因序列设计引物,对实验室嗜热链球菌菌株的Cas基因进行扩增、测序,分析实验室6株嗜热链球菌的CRISPR-Cas系统情况.[结果]9株标准菌株均含不同数目的CRISPR-Cas系统,其类型主要为Ⅱ-A型、Ⅲ-A型和Ⅰ-E型,各类型的标志Cas基因高度保守.6株供试菌中,S4仅含Cas9基因,其它5株均含有Cas9基因、Ca1O基因和Cas9*基因,79和KLDS3.0207还含有Cas3基因.[结论]可根据标准菌株高度保守的Cas基因设计引物,预测未知嗜热链球菌所含CRISPR-Cas系统的数目和类型.S4仅含1个Ⅱ-A型CRISPR-Cas系统,其它5株均含有2个Ⅱ-A型CRISPR-Cas系统和1个Ⅲ-A型CRISPR-Cas系统,此外,79和KLDS3.0207均含有1个Ⅰ-E型CRISPR-Cas系统.

  8. Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria

    OpenAIRE

    Xue Han; Zhe Yang; Xueping Jing; Peng Yu; Yingchun Zhang; Huaxi Yi; Lanwei Zhang

    2016-01-01

    19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricu...

  9. The physiological functions of capsule polysaccharide produced by streptococcus salivarius subsp. Thermophilus%唾液链球菌嗜热亚种荚膜多糖生理功能特性研究

    Institute of Scientific and Technical Information of China (English)

    顾瑞霞; 刘爱萍; 程涛; 骆承庠

    2000-01-01

    通过对唾液链球菌嗜热亚种的研究发现,细胞固有发酵活性、抵抗外界不良环境能力与荚膜无关.破坏唾液链球菌嗜热亚种LCX2001的荚膜,会使发酵速度加快,但同时对外界不良环境的抵抗力下降.这些研究结果表明,有无荚膜,或荚膜大小对同一亚种所表现出来的不同生理特性没有决定作用;破坏荚膜,会影响细胞体与外界物质交换能力,对细胞体许多生理功能有影响;荚膜起到阻止外界物质的进入细胞和细胞内产生的乳酸向外界释放的作用.

  10. Study on Flavour Compounds Analysis in Milk by Coculturing with Streptococcus salivarius subsp.thermophilus%唾液链球菌嗜热亚种发酵乳风味成分分析

    Institute of Scientific and Technical Information of China (English)

    王伟军; 李延华; 张兰威; 于俊林

    2008-01-01

    本实验使用同时蒸馏萃取-气谱-质谱(SDE-GC-MS)技术对5株唾液链球菌嗜热亚种S.t-9、S.t-17YA、S.t-1703CA、S.t-1703D和S.t-03发酵乳中风味物质进行了定性及定量分析,分别鉴定出24种、20种、13种、20种、21种风味物质,共涉及6大类:酸类化合物、酯类化合物、醇类化合物、羰基化合物、芳环和杂环化合物,35种物质.另外,5株菌代谢主要风味物质2,3.丁二酮的能力大小为:S.t-1703D>S.t-1703CA>S.t-17YA>S.t-03>S.t-9,除S.t-9菌代谢2,3-丁二酮量较低外,其它4种菌代谢丁二酮的能力差异不大.

  11. KINETICS OF EXOPOLYSACCHARIDE BY STREPTOCOCCUS SALIVARIUS SUBSP. THERMOPHILUS LCX2001 FERMENTATION FOR PRODUCTION OF EXOPOLYSACCHARIDE%唾液链球菌嗜热亚种LCX2001胞外多糖分批发酵动力学

    Institute of Scientific and Technical Information of China (English)

    顾瑞霞; 刘爱萍; 骆承庠

    2001-01-01

    对唾液链球菌嗜热亚种LCンX2001生物合成胞外多糖(EPS)的动力学进行了研究,基于Logistic-equation方程和Luedeking-piret方程,得到了描述发酵过程的动力学模型和模型参数.该模型反映了细胞生长、乳酸生成、EPS生物合成和基质消耗之间的关系,模型的拟合结果与实验值吻合较好,误差小于10%.

  12. Optimization of Carrot Yoghurt Production by Fermentation of Immobilized Lactobacillus delbrueckii subsp bulgaricus and Streptococcus salivarius subsp thermophilus%固定化乳酸菌发酵胡萝卜酸奶工艺研究

    Institute of Scientific and Technical Information of China (English)

    吴定; 孙嘉文; 姚明兰; 路桂红

    2010-01-01

    通过固定化乳酸菌发酵胡萝卜酸奶,建立新的胡萝卜酸奶发酵工艺.经过单因素试验和正交试验,确定固定化乳酸菌发酵胡萝卜酸奶的配方和发酵工艺.胡萝卜酸奶的配方:奶粉9g、胡萝卜13g、白砂糖8g、蒸馏水100mL.胡萝卜酸奶发酵工艺:固定化德氏乳杆菌保加利亚亚种与固定化唾液链球菌嗜热亚种的比为2:1接种发酵液(菌种的总添加量为6g/100mL)、在37℃发酵培养7h、然后4℃冷藏12h.结果表明,采用固定化乳酸菌新技术可以发酵生产营养丰富、口感良好的胡萝卜酸奶.

  13. Scientific Opinion on the safety and efficacy of Probiotic LACTINA® (Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus lactis, Streptococcus thermophilus and Enterococcus faecium for chickens for fattening and piglets

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-04-01

    Full Text Available Probiotic LACTINA® is a feed additive consisting of six strains of lactic acid bacteria. In 2007 the European Food Safety Authority was requested to evaluate the safety and efficacy of the additive when used as a zootechnical additive (functional group: gut flora stabilisers in diets for chickens for fattening, piglets and pigs for fattening. At that time the FEEDAP Panel was able to conclude only on the safety for the environment. EFSA is now requested to assess the safety for the target animals and consumers, and the efficacy of the additive when added in diets for chickens for fattening at 5 x 108 - 9 x 109 CFU/kg feed and for piglets at 9 x 108 - 1 x 1010 CFU/kg feed. The identity of the six strains was established. As no antibiotic resistance of concern was detected and as five of the strains qualify for the Qualified Presumption of Safety approach to safety assessment, their use is presumed safe for target species and consumers. The Enterococcus faecium strain is not a recognised pathogen for animals and as the additive did not adversely affect growth of chickens or piglets, Probiotic LACTINA® is considered safe for the target species up to 1 x 1010 CFU/kg feed. The E. faecium strain does not contain marker genes typical of hospital-associated isolates responsible for clinical infections. The metabolic pathways of E. faecium are well known. Since no other harmful metabolites are expected and the additive does not contain excipients of concern, it is considered safe for consumers. Probiotic LACTINA® showed a potential to increase the body weight of suckling piglets when used at approximately 5 x 109 CFU/kg feed. The Panel could not conclude on the efficacy of Probiotic LACTINA® when used in diets for chickens for fattening or weaned piglets.

  14. Study on co-culture of Yeast and Streptococcus.thermophilus with Apple Pomace%苹果渣制备饲料酵母和嗜热链球菌

    Institute of Scientific and Technical Information of China (English)

    李瑛; 吕嘉枥

    2011-01-01

    With apple pomace-based materials, separate and mixed culture of yeast and Streptococcus thermophilusiS. T) was studied. The respective growth curves of them under different temperature were discussed, and on this basis, the feasibili-ty of the mixed culture was studied. The results indicated that : in separate fermentation the total number of viable cells was up to 4. 32× 108 cfu/ml, in staged constant-temperature-fermentation (first 4% yeast inoculated and cultured at 35℃ for 2 d, then 2% S. T inoculated) the total number of viable was up to 6. 53 X 108 cfu/ml, and in staged variable-temperature-fermenta-tion(first 4% yeast inoculated and cultured at 32℃ for 2 d, then up to 37℃ , 2% of S. T inoculated) the total number of viable cells was up to 7. 21× 108 cfu/ml, there were no major differences. Thus, the use of apple pomace mixed culture of yeasts and S. T was indeed feasible.%以苹果渣为主料,分别单独和混合培养饲料酵母菌和嗜热链球菌.探讨了各自在不同温度下的生长曲线,并在此基础上研究了混合培养的可行性.结果显示:单独发酵活菌总数可达4.32×108 cfu/ml,分段恒温发酵(35℃下培养,先接入4%酵母菌培养2d,再接入2%嗜热链球菌)活菌总数可达6.53×108 cfu/ml,分段变温培养(32℃下先接入4%酵母菌培养2d,再将温度调制37℃接入2%嗜热链球菌)活菌总数可达7.21×108 cfu/ml,没有较大差异.由此可见,利用苹果渣混合培养酵母菌和嗜热链球菌确实可行.

  15. Protein: FBB4 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB4 T. thermophilus V-ATPase atpC ... V-type ATP synthase subunit C ... V-ATPase subunit C ... 300852 Therm ... us thermophilus (strain HB8 / ATCC ... 27634 / DSM 579) 3168086 P74902 1R5Z, 3J0J 1V9M ...

  16. Dicty_cDB: Contig-U12103-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available d:none) Prochlorococcus marinus str. AS9... 96 3e-18 AY057845_38( AY057845 |pid:none) Zymomonas mobili...962( AM263198 |pid:none) Listeria welshimeri serovar 6b s... 94 2e-17 CP000879_1482( CP000879 |pid:none) Petrotoga mobili...( AY427777 |pid:none) Canis familiaris isolate AS22 ABCA... 141 8e-32 AY028899_1( AY028899 |pid:none) Homo sapiens ATP-bi..._1961( CP000885 |pid:none) Clostridium phytofermentans ISD... 102 3e-20 CP000117_418( CP000117 |pid:none) Anabaena variabili...acter thermautotr... 98 7e-19 CP001034_1544( CP001034 |pid:none) Natranaerobius thermophil

  17. 一株嗜热菌的分离、鉴定及海藻糖合成酶基因的克隆%Isolation and Identification of a Thermophile Bacterium and Cloning of Trehalose Synthase Gene

    Institute of Scientific and Technical Information of China (English)

    王慧荣; 韦宇拓; 黄日波

    2011-01-01

    从广西贺州市80℃热泉分离了一株嗜热菌TTH,生长温度范围在55℃~85℃,最适生长温度70℃左右,最高生长温度85℃,G+C物质的量分数为67.6%.对菌株TTH从形态、培养条件、16S rRNA基因序列和系统发育分析方面进行了研究,表明该菌株与3株嗜热栖热菌(Thermus thermophilus)的同源性达到98%,初步鉴定是嗜热栖热菌(Thermus thermophilus).克隆了该菌的海藻糖合成酶基因,它与菌株Thermus thermophilus RQ-1,Thermus caldophilus,Thermus thermophilus HB8,Thermus thermophilus的同源性达到87%.%A thermophile strain, designated as TTH, was isolated from 80℃ hot spring at Hezhou county in Guangxi province. It could grow at temperatures from 55℃ to 85℃, with the optimal temperature 70℃, the highest temperature 85℃ , and with 67. 6% molar content of the G + C. The researches which were based on the TTH morphological , culture conditions, 16S rDNA sequence, as well as the phylogenetic analysis show that the strain TTH has 98% sequence identity with three kinds of Thennus thermophilus. Therefore the strain is tentatively identified as Thermits thermophilus. Trehalose synthase gene of TTH was cloned and analyzed. It has 87% identity to the treS gene from Thermits thermophilus RQ-1, Thermits caldophilus, Thermits thermophilus HB8 and Thermits thermophilus.

  18. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to the substantiation of health claims related to various microorganisms and changes in bowel function, and digestion and absorption of nutrients (ID 960, 961, 967, 969, 971, 975, 983, 985, 994, 996, 998, 1006, 1014), decreasing potentially pathogenic gastro-intestinal microorganisms (ID 960, 967, 969, 971, 975, 983, 985, 994, 996, 998, 1006, 1014), and stimulation of immunological responses (ID 962, 968, 970, 972, 976, 984, 986, 995, 997, 999, 1007, 1015) (further assessment) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    030802, Lactobacillus salivarius THT 031001 and Streptococcus thermophilus THT 070102, are sufficiently characterised. The evidence provided did not establish that the proposed claimed effect, stimulation of immunological responses, is a beneficial physiological effect. The references provided...

  19. Protein: FBB5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB5 RNA modification mnmG gidA tRNA uridine 5-carboxymethylaminomethyl modification enzyme MnmG ... 52 Thermus thermophilus (strain HB8 / ATCC 27634 / DSM ... 579) 3169842 Q5SGV8 ...

  20. Protein: FBB5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB5 RNA modification queA S-adenosylmethionine:tRNA ribosyltransferase-isomerase Queuosine bios ... 52 Thermus thermophilus (strain HB8 / ATCC 27634 / DSM ... 579) 3169205 Q5SMH0 ...

  1. Protein: FBB5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB5 RNA modification secDF Protein translocase subunit SecDF 300852 Thermus thermophilus (strai ... n HB8 / ATCC 27634 / DSM ... 579) 3168575 Q5SKE6 3AQP, 2RRN, 3AQO 21562494 #201 ...

  2. Protein: FBB5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB5 RNA modification secY Protein translocase subunit SecY 300852 Thermus thermophilus (strain ... HB8 / ATCC 27634 / DSM ... 579) 3169829 Q5SHQ8 2ZJS, 2ZQP 18923527 #20081016 ...

  3. Protein: FBB4 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB4 Reductase TT_C0153 Hypothetical membrane spanning protein 262724 Thermus thermophilus (stra ... in HB27 / ATCC BAA-163 / DSM ... 7039) 2774686 Q72LA6 2VPX, 2VPY, 2VPW, 2VPZ 185367 ...

  4. Protein: FBB5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB5 RNA modification tgt Queuine tRNA-ribosyltransferase Guanine insertion enzyme, tRNA-guanine ... 52 Thermus thermophilus (strain HB8 / ATCC 27634 / DSM ... 579) 3168583 Q5SLI7 ...

  5. Diversity, Activity, and Evolution of CRISPR Loci in Streptococcus thermophilus▿ †

    OpenAIRE

    Horvath, Philippe; Romero, Dennis A.; Coûté-Monvoisin, Anne-Claire; Richards, Melissa; Deveau, Hélène; Moineau, Sylvain; Boyaval, Patrick; Fremaux, Christophe; Barrangou, Rodolphe

    2007-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are hypervariable loci widely distributed in prokaryotes that provide acquired immunity against foreign genetic elements. Here, we characterize a novel Streptococcus thermophilus locus, CRISPR3, and experimentally demonstrate its ability to integrate novel spacers in response to bacteriophage. Also, we analyze CRISPR diversity and activity across three distinct CRISPR loci in several S. thermophilus strains. We show that both ...

  6. Production of Synbiotic Yogurt-Like Using Indigenous Lactic Acid Bacteria as Functional Food

    Directory of Open Access Journals (Sweden)

    M. Astawan

    2012-04-01

    Full Text Available Yoghurt is a product of fermented milk using Lactobacillus bulgaricus and Streptococcus thermophilus as culture starter. Indigenous probiotic lactic acid bacteria, Lactobacillus plantarum 2C12 or Lactobacillus acidophilus 2B4, were applied in the making of functional synbiotic yoghurt-like with 5% of fructo-oligosaccharide (FOS as a prebiotic source. The aim of this study was to determine the best formula of functional synbiotic yoghurt-like among four formulas: F1 (L. bulgaricus + S. thermophilus, F2 (L. bulgaricus + S. thermophilus + L. plantarum 2C12, F3 (L. bulgaricus+ S. thermophilus + L. acidophilus 2B4, and F4 (L. bulgaricus + S. thermophilus + L. plantarum 2C12 + L. acidophilus 2B4 to be choosen and followed detection of it’s flavor to improve the product quality and consumer acceptance. The results showed that the F3 synbiotic yogurt made from mixed culture L. bulgaricus, S. thermophilus, and L. acidophilus 2B4 had the highest antibacterial effect against Enteropathogenic Escherichia coli (EPEC. Addition of 1.75% natural corn starch as a stabilizer produced optimum improvement in yoghurt consistency and minimize whey separation. Result of sensory evaluation indicated that the yoghurt with addition of 1% strawberry flavor and 0.1% vanilla flavor were ranked at first and second. Yoghurts were still good to be consumed after 15 d storage period at the refrigeration temperature (10 oC.

  7. 唾液链球菌嗜热亚种LCX2001胞外多糖合成条件的研究%Study on Exopolysaccharide Synthesis by Streptococcus salivarius subsp.thermophilus LCX2001 Grown in Chemically Defined Medium

    Institute of Scientific and Technical Information of China (English)

    顾瑞霞; 刘爱萍; 程涛; 骆承庠

    2000-01-01

    从众多的用于乳酸菌生长的合成和半合成培养基(MRS、M17、ATP、SL、Elliker、SDM),选择了ATP作为唾液链球菌嗜热亚种LCX2001胞外多糖产生的基本培养基,在此基础上开发了LCX合成培养基,并对碳源、培养基的初始pH、发酵温度和发酵时间进行了探讨.该菌生物合成EPS的工艺条件为:葡萄糖和/或乳糖是该菌株合成EPS的合适的碳源,添加量为20g/L,培养基的初始pH值为6.5,发酵温度为35℃,发酵时间为20h.

  8. Thermostabilization of desulfurization enzymes from Rhodococcos sp. IGTS8. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane II

    2000-12-15

    The objective of this project was to develop thermophilic cultures capable of expressing the desulfurization (dsz) operon of Rhodococcus sp. IGTS8. The approaches taken in this project included the development of plasmid and integrative expression vectors that function well in Thermus thermophilus, the cloning of Rhodococcus dsz genes in Thermus expression vectors, and the isolation of bacterial cultures that express the dsz operon at thermophilic temperatures. This project has resulted in the development of plasmid and integrative expression vectors for use in T. thermophilus. The dsz genes have been expressed at moderately thermophilic temperatures (52 C) in Mycobacterium phlei and at temperatures as high as 72 C in T. thermophilus. The tools and methods developed in this project will be generally useful for the expression of heterologous genes in Thermus. Key developments in the project have been the isolation of a Mycobacterium phlei culture capable of expressing the desulfurization operon at 52 C, development of plasmid and integrative expression vectors for Thermus thermophilus, and the development of a host-vector system based on the malate dehydrogenase gene that allows plasmids to be stably maintained in T. thermophilus and provides a convenient reporter gene for the accurate quantification of gene expression. Publications have been prepared regarding each of these topics; these preprints are included.

  9. Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product

    Directory of Open Access Journals (Sweden)

    Abdelkader Mezaini

    2009-01-01

    Full Text Available In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria. Streptococcus thermophilus T2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, by S. thermophilus T2 cells, was measured by the end of the late-log phase (90 AU ml−1 with a bacteriocine production rate of 9.3 (AU ml−1 h−1. In addition, our findings showed that the bacteriocin, produced by S. thermophilus T2, was stable over a wide pH range (4–8; this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food.

  10. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) Scientific Opinion on the substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus

    DEFF Research Database (Denmark)

    Tetens, Inge

    substantiation of a health claim related to a combination of Bifidobacterium longum LA 101, Lactobacillus helveticus LA 102, Lactococcus lactis LA 103 and Streptococcus thermophilus LA 104 and improves stools frequency. The food that is the subject of the health claim is a combination of B. longum LA 101, L...... and effect relationship cannot be established between the consumption of a combination of B. longum LA 101, L. helveticus LA 102, L. lactis LA 103 and S. thermophilus LA 104 and improves stool frequency. © European Food Safety Authority, 2013...

  11. Probiotinių mikroorganizmų įtaka pieno rūgšties izomerų kiekiui jogurte

    OpenAIRE

    Garmienė, G.; Kulikauskienė, M.; Saikauskienė, V.

    2005-01-01

    Fermentiniu metodu tirtas pieno rūgšties izomerų kiekis jogurte. Nustatyta, kad jogurto gamyboje kartu vartojant tradicinių pieno rūgšties bakterijų Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus ir probiotinių kultūrų Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei subsp. casei mišinius bei didinant santykinį S. thermophilus kiekį bendroje tradicinių jogurto kultūrų masėje, galima produktui suteikti ne tik pageidaujamas kokybines savybes, bet ir sumaž...

  12. 21 CFR 131.206 - Nonfat yogurt.

    Science.gov (United States)

    2010-04-01

    ... solids not fat, and has a titratable acidity of not less than 0.9 percent, expressed as lactic acid. The... specified in paragraph (c) of this section with a characterizing bacterial culture that contains the lactic acid-producing bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus. One or more of...

  13. 21 CFR 131.203 - Lowfat yogurt.

    Science.gov (United States)

    2010-04-01

    ..., expressed as lactic acid. The food may be homogenized and shall be pasteurized or ultra-pasteurized prior to... specified in paragraph (c) of this section with a characterizing bacterial culture that contains the lactic acid-producing bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus. One or more of...

  14. 21 CFR 131.200 - Yogurt.

    Science.gov (United States)

    2010-04-01

    ... solids not fat, and has a titratable acidity of not less than 0.9 percent, expressed as lactic acid. The... in paragraph (c) of this section with a characterizing bacterial culture that contains the lactic acid-producing bacteria, Lactobacillus bulgaricus and Streptococcus thermophilus. One or more of...

  15. Prokysávací schopnosti mlékárenské suroviny

    OpenAIRE

    BOUŠKOVÁ, Lucie

    2012-01-01

    The evaluation of changes during fermentation of heat-modified milk in connection with different fermentation temperatures was main goal of this thesis. Titrable acidity, active acidity and growth dynamics of bacteria strains - Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus were observed during fermentation process.

  16. Biochemical Characteristics and Viability of Probiotic and Yogurt Bacteria in Yogurt during the Fermentation and Refrigerated Storage

    Directory of Open Access Journals (Sweden)

    F Sarvari

    2014-09-01

    Full Text Available This research aimed to investigate the viability of probiotic bacteria (Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12 and yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus in yogurt during the fermentation, immediately after fermentation and during refrigerated storage (21 d, 4˚C. Also the biochemical characteristics of milk as affected by the commercial 4-strain mixed starter culture were investigated. Storage time affected the viability of all bacterial species. The concentration of lactic acid during the fermentation increased in parallel with the titrable acidity, and the concentration of acetic acid was proportional to the viability of Bifidobacterium lactis. The acetaldehyde level was decreased in the yogurt from day 0 up to the end of the storage. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were multiplied considerably during the fermentation. Streptococcus thermophilus could maintain its viability to the highest level, but Lactobacillus delbrueckii ssp. bulgaricus lost its viability rapidly during the cold storage compared to Streptococcus thermophilus. The multiplication and viability of probiotic bacteria were also influenced by the associative strains and species of yogurt organisms. Bifidobacteria counts were satisfactory. The loss of viability for bifidobacteria was gradual and steady during the storage, and they showed good stability during the storage as compared to Lactobacillus acidophilus.

  17. Influence of fructooligosaccharides on the fermentation profile and viable counts in a symbiotic low fat milk

    Science.gov (United States)

    Oliveira, Ricardo P.S.; Casazza, Alessandro A.; Aliakbarian, Bahar; Perego, Patrizia; Converti, Attilio; Oliveira, Maricê N.

    2013-01-01

    This study evaluated the effects of prebiotics on fermentation profile and growth of Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhamnosus, and Bifidobacterium lactis in co-cultures with Streptococcus thermophilus. Acidification rate and viability were positively influenced by the co-culture with B. lactis and by both inulin or oligofructose in low fat milk. PMID:24294233

  18. Influence of fructooligosaccharides on the fermentation profile and viable counts in a symbiotic low fat milk

    Directory of Open Access Journals (Sweden)

    Ricardo P.S. Oliveira

    2013-01-01

    Full Text Available This study evaluated the effects of prebiotics on fermentation profile and growth of Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhamnosus, and Bifidobacterium lactis in co-cultures with Streptococcus thermophilus. Acidification rate and viability were positively influenced by the co-culture with B. lactis and by both inulin or oligofructose in low fat milk.

  19. ANTIMICROBIAL ACTIVITY AND PHOTOCHEMICAL SCREENING OF TINOSPORA CORDIFOLIA AND EUPHORBIA HIRTA

    OpenAIRE

    Amit Sandhu; Neha bhardwaj; Vikas Menon; Ruby Gupta

    2013-01-01

    The present study deals with the antimicrobial activity and phytochemical screening of the two medicinal plants, Tinospora cordifolia and Euphorbia hirta those are commonly available in India. Results of antimicrobial activity revealed that these medicinal plant extracts were very effective against Serratia marcescens, E. coli, Streptococcus thermophilus, Fusarium oxysporium, Aspergillus niger while these extracts showed very less inhibition against Trichoderma reesei. Phytochemical analysis ...

  20. 76 FR 66187 - Bacteriophage of Clavibacter Michiganensis Subspecies Michiganensis; Exemption From the...

    Science.gov (United States)

    2011-10-26

    ... thermophilus phages in a large- production cheese factory in Argentina. Journal of Dairy Science 89:3791-3799... agricultural practices. On behalf of OmniLytics, Inc., Interregional Research Project Number 4 (IR-4) submitted... Findings In the Federal Register of September 23, 2009 (74 FR 48556) (FRL- 8434-7), EPA issued a...

  1. Examination of middle concentrations of oxytetracycline residues in cow milk after intrauterine application

    OpenAIRE

    Vuković V.; Kasalica A.; Vićentijević M.

    2011-01-01

    After intrauterine application of oxytetracycline in a dose of 2.0 g per cow, excretion of residues in milk was monitored using Resasurine test with Str. thermophilus and specific quantitative procedure (Vukovic, 1999). Mean concentrations of oxytetracycline residues in milk samples, the total quantity per milking and the total quantity per cow were monitored.

  2. Production of Volatile Compounds in Reconstituted Milk Reduced-Fat Cheese and the Physicochemical Properties as Affected by Exopolysaccharide-Producing Strain

    Directory of Open Access Journals (Sweden)

    Weijun Wang

    2012-12-01

    Full Text Available The application of the exopolysaccharide-producing strains for improving the texture and technical properties of reduced-fat cheese looks very promising. Streptococcus thermophilus TM11 was evaluated for production of reduced-fat cheese using reconstituted milk powder (CRMP. The physicochemical analysis of fresh and stored cheeses showed that this strain slightly increased moisture content resulting in cheese with higher yield and lower protein content compared to the direct acidified cheese. The volatiles of cheese were determined by SPME and GC equipped with a mass spectrometer. The results indicated that the major compounds included aldehydes, ketones and acids, whereas, alcohols and branched-chain aldehydes that contribute to exciting and harsh flavors were not found in CRMP. By the textural profile analysis, we found the cheese made with S. thermophilus TM11 had lower cohesiveness, resilience and higher adhesiveness than the direct acidified cheese, and had similar hardness. Further, S. thermophilus TM11 greatly changed the protein matrix with more opened cavities according to observation by scanning electron microscopy. Consequently, use of S. thermophilus TM11 could endow CRMP with the novel and suitable flavor properties and improved texture quality.

  3. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    DEFF Research Database (Denmark)

    Wong, Jaslyn E M M; Midtgaard, Søren Roi; Gysel, Kira; Thygesen, Mikkel B; Sørensen, Kasper K; Jensen, Knud J; Stougaard, Jens; Thirup, Søren; Blaise, Mickaël

    multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering...

  4. Crystal structures at 2.5 Angstrom resolution of seryl-tRNA synthetase complexed with two analogs of seryl adenylate

    DEFF Research Database (Denmark)

    Belrhali, H.; Yaremchuk, A.; Tukalo, M.;

    1994-01-01

    Crystal structures of seryl-tRNA synthetase from Thermus thermophilus complexed with two different analogs of seryl adenylate have been determined at 2.5 Angstrom resolution. The first complex is between the enzyme and seryl-hydroxamate-AMP (adenosine monophosphate), produced enzymatically in the...

  5. Survival of Yogurt Bacteria in the Human Gut

    OpenAIRE

    Elli, Marina; Callegari, Maria Luisa; Ferrari, Susanna; Bessi, Elena; Cattivelli, Daniela; Soldi, Sara; Morelli, Lorenzo; Goupil Feuillerat, Nathalie; Antoine, Jean-Michel

    2006-01-01

    Whether Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus can be recovered after passage through the human gut was tested by feeding 20 healthy volunteers commercial yogurt. Yogurt bacteria were found in human feces, suggesting that they can survive transit in the gastrointestinal tract.

  6. DEGRADATION OF MILK-BASED BIOACTIVE PEPTIDES BY YOGURT FERMENTATION BACTERIA

    Science.gov (United States)

    The effect of cell associated peptidases in yogurt starter culture strains Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus on milk-protein based antimicrobial and hypotensive peptides was evaluated to determine their survival in yogurt-type dairy foods. The 11mer antimicr...

  7. STUDY OF THE COMBINED EFFECTS OF ARABINOGALACTAN AND LACTULOSE ON THE DEVELOPMENT OF THE STARTER CULTURES FOR YOGHURT Исследование совместного влияния арабиногалактана и лактулозы на развитие закваски для йогурта

    Directory of Open Access Journals (Sweden)

    Zavezenova I. V.

    2013-05-01

    Full Text Available In this article, we present the results of the research of influence of polysaccharides and prebiotics on physical, chemical, rheological, microbiological and organoleptic indicators of a sour-milk product on the basis of ferment starting cultures of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. The optimum dose of polysaccharides and prebiotics adding into a sour-milk product is proved

  8. Protein: FBB5 [TP Atlas

    Lifescience Database Archive (English)

    Full Text Available FBB5 RNA modification TTHA0533 Probable ribosomal RNA small subunit methyltransferase 300852 The ... rmus thermophilus (strain HB8 / ATCC 27634 / DSM ... 579) 3169440 Q5SKW0 3DMF, 3DMH, 3DMG 2ZUL, 2ZWV ...

  9. Rice8987 g_array: cDNA information: 950 [RMOS[Archive

    Lifescience Database Archive (English)

    Full Text Available g_0950 CH2920 >AB010884_1(AB010884|pid:g3062847) Thermus thermophilus fumC and sodA genes for cl ... ass II fumarase and manganese ... superoxide dismutase, complete cds. DPlate 023 C08 ...

  10. Nisin-induced Expression of Pediocin in Dairy Lactic Acid Bacteria

    Science.gov (United States)

    To test if a single vector, nisin-controlled expression (NICE) system could be used to regulate expression of the pediocin operon in Streptococcus thermophilus, Lactococcus lactis subsp. lactis and Lactobacillus casei, the intact pediocin operon was cloned into pMSP3535 immediately down stream of th...

  11. Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids

    Science.gov (United States)

    Helinck, Sandra; Le Bars, Dominique; Moreau, Daniel; Yvon, Mireille

    2004-01-01

    Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus to produce aroma compounds from three amino acids, leucine, phenylalanine, and methionine, under mid-pH conditions of cheese ripening (pH 5.5), and we investigated the catabolic pathways used by these bacteria. In the three lactic acid bacterial species, amino acid catabolism was initiated by a transamination step, which requires the presence of an α-keto acid such as α-ketoglutarate (α-KG) as the amino group acceptor, and produced α-keto acids. Only S. thermophilus exhibited glutamate dehydrogenase activity, which produces α-KG from glutamate, and consequently only S. thermophilus was capable of catabolizing amino acids in the reaction medium without α-KG addition. In the presence of α-KG, lactobacilli produced much more varied aroma compounds such as acids, aldehydes, and alcohols than S. thermophilus, which mainly produced α-keto acids and a small amount of hydroxy acids and acids. L. helveticus mainly produced acids from phenylalanine and leucine, while L. delbrueckii subsp. lactis produced larger amounts of alcohols and/or aldehydes. Formation of aldehydes, alcohols, and acids from α-keto acids by L. delbrueckii subsp. lactis mainly results from the action of an α-keto acid decarboxylase, which produces aldehydes that are then oxidized or reduced to acids or alcohols. In contrast, the enzyme involved in the α-keto acid conversion to acids in L. helveticus and S. thermophilus is an α-keto acid dehydrogenase that produces acyl coenzymes A. PMID:15240255

  12. Genomics of Streptococcus salivarius, a major human commensal.

    Science.gov (United States)

    Delorme, Christine; Abraham, Anne-Laure; Renault, Pierre; Guédon, Eric

    2015-07-01

    The salivarius group of streptococci is of particular importance for humans. This group consists of three genetically similar species, Streptococcus salivarius, Streptococcus vestibularis and Streptococcus thermophilus. S. salivarius and S. vestibularis are commensal organisms that may occasionally cause opportunistic infections in humans, whereas S. thermophilus is a food bacterium widely used in dairy production. We developed Multilocus sequence typing (MLST) and comparative genomic analysis to confirm the clear separation of these three species. These analyses also identified a subgroup of four strains, with a core genome diverging by about 10%, in terms of its nucleotide sequence, from that of S. salivarius sensu stricto. S. thermophilus species displays a low level of nucleotide variability, due to its recent emergence with the development of agriculture. By contrast, nucleotide variability is high in the other two species of the salivarius group, reflecting their long-standing association with humans. The species of the salivarius group have genome sizes ranging from the smallest (∼ 1.7 Mb for S. thermophilus) to the largest (∼ 2.3 Mb for S. salivarius) among streptococci, reflecting genome reduction linked to a narrow, nutritionally rich environment for S. thermophilus, and natural, more competitive niches for the other two species. Analyses of genomic content have indicated that the core genes of S. salivarius account for about two thirds of the genome, indicating considerable variability of gene content and differences in potential adaptive features. Furthermore, we showed that the genome of this species is exceptionally rich in genes encoding surface factors, glycosyltransferases and response regulators. Evidence of widespread genetic exchanges was obtained, probably involving a natural competence system and the presence of diverse mobile elements. However, although the S. salivarius strains studied were isolated from several human body-related sites

  13. The size and shape of three water-soluble, non-ionic polysaccharides produced by lactic acid bacteria: A comparative study.

    Science.gov (United States)

    Dalheim, Marianne Øksnes; Arnfinnsdottir, Nina Bjørk; Widmalm, Göran; Christensen, Bjørn E

    2016-05-20

    Three water-soluble, non-ionic extracellular polysaccharides (EPS) obtained from lactic acid bacteria (S. thermophilus THS, L. helveticus K16 and S. thermophilus ST1) were subjected to a comparative study by means of multidetector size-exclusion chromatography, providing distributions and averages of molar masses, radii of gyration and intrinsic viscosities. All polysaccharides displayed random coil character. Further analysis of the data reveals differences in chain stiffness and extension that could be well correlated to structural features. The calculated persistence lengths ranged from 5 to 10nm and fall within the range typical for many single-stranded bacterial or plant polysaccharides. The ST1 polysaccharide had the highest molar mass but the lowest persistence length, which is attributed to the presence of the flexible (1→6)-linkage in the main chain. PMID:26917378

  14. Effect of oxidoreduction potential on aroma biosynthesis by lactic acid bacteria in nonfat yogurt.

    Science.gov (United States)

    Martin, F; Cachon, R; Pernin, K; De Coninck, J; Gervais, P; Guichard, E; Cayot, N

    2011-02-01

    The aim of this study was to investigate the effect of oxidoreduction potential (Eh) on the biosynthesis of aroma compounds by lactic acid bacteria in non-fat yogurt. The study was done with yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus. The Eh was modified by the application of different gaseous conditions (air, nitrogen, and nitrogen/hydrogen). Acetaldehyde, dimethyl sulfide, diacetyl, and pentane-2,3-dione, as the major endogenous odorant compounds of yogurt, were chosen as tracers for the biosynthesis of aroma compounds by lactic acid bacteria. Oxidative conditions favored the production of acetaldehyde, dimethyl sulfide, and diketones (diacetyl and pentane-2,3-dione). The Eh of the medium influences aroma production in yogurt by modifying the metabolic pathways of Lb. bulgaricus and Strep. thermophilus. The use of Eh as a control parameter during yogurt production could permit the control of aroma formation. PMID:21257030

  15. Bacteriological quality of freshly processed broiler chickens as affected by carcass pretreatment and gamma irradiation

    International Nuclear Information System (INIS)

    Chicken carcasses dipped in whey fermented by Streptococcus thermophilus, lactic acid solution or water and irradiated at 2.5 kGy by 60Co were evaluated for bacteriological quality on day 1, day-3 and at 3-day intervals for an 18-day storage (4 degrees C) period. Unirradiated carcasses treated similarly were used as control. Gram negative bacteria, Yersinia and Campylobacter counts were significantly (p0.01) lower in irradiated samples, but no significant (p0.05) differences were observed ammong the dipping solutions. Salmonellae were completely eliminated in irradiated samples. Whey fermented by S. thermophilus reduced the proportion of Salmonella contaminated carcasses from 67% to 20%. As evidenced by the bacterial counts the shelf-life was found to be 15 days for irradiated carcasses compared to about 6 days for the unirradiated samples

  16. Acceptability of yoghurt and probiotic yoghurt from goat’s milk

    Directory of Open Access Journals (Sweden)

    Rajka Božanić

    2001-10-01

    Full Text Available From goat’s milk with 2% of inoculum of yoghurt culture DVS-YC 180(Streptococcus thermophilus and Lactobacillus delbrueckii subsp.bulgaricus, and mixed ABT 4 culture (Lactobacillus acidophilus,Streptococcus thermophilus and Bifidobacterium spp firm fermentedbeverages were produced. The influence of whey protein concentrate and milk powder addition, at the concentration of 2 %, on fermentation and samples acceptability was investigated. Whey protein concentrate and milk powder addition improved the consistency and sensory characteristic of the products. Probiotics yoghurt had slightly higher sensory properties. After hedonic scaleevaluation the control yoghurt samples and control probiotic yoghurt samples were not acceptable. Analysis of variance showed significant differences between investigated yoghurt and probiotic yoghurt, and Duncan test showed that yoghurt and probiotic yoghurt samples with additives were significantly different from others, i.e., they proved to be better then control samples.

  17. AcEST: BP914129 [AcEST

    Lifescience Database Archive (English)

    Full Text Available N=ser1 PE=1 SV=2 33 0.34 sp|Q6CSR7|SFH1_KLULA Chromatin structure-remodeling complex subu... 33 0.58 sp|P22865|USP45_LACLM Secre...LAGSSTSGGSS 921 >sp|Q6CSR7|SFH1_KLULA Chromatin structure-remodeling complex subunit SFH1 OS=Kluyveromyces lact...ted 45 kDa protein OS=Lactococcus lac... 32 0.99 sp|Q5M5Z0|SSTT_STRT2 Serine/threonine transporter sstT OS=Strep...: 320 GNTNSGTSTGNTGGTTTGGS 339 >sp|Q5M5Z0|SSTT_STRT2 Serine/threonine transporter sstT OS=Streptococcus thermophilus (str...ILSVVSTISACGASGIAGGSLLLVPVACSLFGISNDLA 361 >sp|Q5M1F4|SSTT_STRT1 Serine/threonine transporter sstT OS=Streptococcus thermophilus (str

  18. Influence of myrtle juice and syrup on microbiological, physicochemical, and sensory features of goat’s milk yogurt made with indigenous starter Culture

    OpenAIRE

    Mangia, Nicoletta Pasqualina; Murgia, Marco Ambrogio; FANCELLO, FRANCESCO; Nudda, Anna; Deiana, Pietrino

    2014-01-01

    This study evaluated the effect of Myrtle Juice (MJ) and Syrup (MS) on microbiological, physicochemical and sensory features in goat milk yogurt fermented by indigenous Streptococcus thermophilus and Lactobacillus delbruekii subsp. bulgaricus during 30 days of storage. Generally, in all samples, the high LAB number at the end of incubation and the pH values ranging from 4.1 to 4.6 indicates a good effectiveness of the used starter on fermentation process. L. delbrueckii subsp. bulgaricus c...

  19. Characterization of goat milk and potentially symbiotic non-fat yogurt

    OpenAIRE

    Noelia Fernanda Paz; Enzo Gonçalvez de Oliveira; Martha Susana Nuñez de Kairuz; Adriana Noemí Ramón

    2014-01-01

    Combining prebiotics and probiotic microorganisms improve quality in the formulation of foods. In this paper, the characteristics of goat milk and symbiotic yogurt were studied. Raw goat milk was analyzed and the skimming process was optimized. For the formulation of a potentially non-fat symbiotic yogurt made with skimmed goat milk, inulin, gelatin, sugar, and Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. rhamnoshus. ...

  20. Signature Lipids and Stable Carbon Isotope Analyses of Octopus Spring Hyperthermophilic Communities Compared with Those of Aquificales Representatives

    OpenAIRE

    Jahnke, Linda L.; Eder, Wolfgang; Huber, Robert; Hope, Janet M.; Hinrichs, Kai-Uwe; Hayes, John M.; Des Marais, David J.; Cady, Sherry L.; Summons, Roger E.

    2001-01-01

    The molecular and isotopic compositions of lipid biomarkers of cultured Aquificales genera have been used to study the community and trophic structure of the hyperthermophilic pink streamers and vent biofilm from Octopus Spring. Thermocrinis ruber, Thermocrinis sp. strain HI 11/12, Hydrogenobacter thermophilus TK-6, Aquifex pyrophilus, and Aquifex aeolicus all contained glycerol-ether phospholipids as well as acyl glycerides. The n-C20:1 and cy-C21 fatty acids dominated all of the Aquificales...

  1. Phylogenetic analysis of the hyperthermophilic pink filament community in Octopus Spring, Yellowstone National Park

    Energy Technology Data Exchange (ETDEWEB)

    Reysenbach, A.L.; Wickham, G.S.; Pace, N.R. [Indiana Univ., Bloomington, IN (United States)

    1994-06-01

    This study uses a molecular phylogenetic approach to characterize the pink filament community at the outflow of Octopus Spring in Yellowstone National Park. The temperature range of the spring is from 84 to 88 C. The authors show that the pink filaments are most closely related to the hydrogen-oxidizing bacterium Aquifex pyrophilus and a close relative Hydrogenobacter thermophilus. 38 refs., 4 figs., 1 tab.

  2. Efficiency of new fungal cellulase systems in boosting enzymatic degradation of barley straw lignocellulose

    DEFF Research Database (Denmark)

    Rosgaard, L.; Pedersen, S.; Meyer, Anne Boye Strunge

    2006-01-01

    the catalytic glucose yields significantly as compared to those obtained with the benchmark Celluclast + Novozyme 188 blend. A comparison of glucose yields obtained on steam-pretreated barley straw and microcrystalline cellulose, Avicel, indicated that the yield improvements were mainly due to the presence......This study examined the cellulytic effects on steam-pretreated barley straw of cellulose-degrading enzyme systems from the five thermophilic fungi Chaetomium thermophilum, Thielavia terrestris, Thermoascus aurantiacus, Corynascus thermophilus, and Myceliophthora thermophila and from the mesophile...

  3. The Inhibition effect of Yoghurt Starter Culture Metabolites

    OpenAIRE

    ASLIM, Belma; BEYATLI, Yavuz

    2000-01-01

    In this study effect of some separate and combined metabolic compounds produced by lactic acid were tested on food pathogenic and contaminant microorgnasms. For this study, five strains of each Lactobacillus bulgaricus and Streptococcus thermophilus were used. The inhibition effects of the metabolic products (lactic acid, hydrogen peroxide, acetaldehyde, diacetyl) produced by the stains on test bacteria ( Staphylococcus aureus, Escherichia coli) were determined. Also, a random combination...

  4. Polyphasic Approach to Bacterial Dynamics during the Ripening of Spanish Farmhouse Cheese, Using Culture-Dependent and -Independent Methods▿

    OpenAIRE

    Martín-Platero, Antonio M.; Valdivia, Eva; Maqueda, Mercedes; Martín-Sánchez, Inés; Martínez-Bueno, Manuel

    2008-01-01

    We studied the dynamics of the microbial population during ripening of Cueva de la Magahá cheese using a combination of classical and molecular techniques. Samples taken during ripening of this Spanish goat's milk cheese in which Lactococcus lactis and Streptococcus thermophilus were used as starter cultures were analyzed. All bacterial isolates were clustered by using randomly amplified polymorphic DNA (RAPD) and identified by 16S rRNA gene sequencing, species-specific PCR, and multiplex PCR...

  5. Should yoghurt cultures be considered probiotic?

    Science.gov (United States)

    Guarner, Francisco; Perdigon, Gabriela; Corthier, Gérard; Salminen, Seppo; Koletzko, Berthold; Morelli, Lorenzo

    2005-06-01

    Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Consumption of yoghurt has been shown to induce measurable health benefits linked to the presence of live bacteria. A number of human studies have clearly demonstrated that yoghurt containing viable bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii sp. bulgaricus) improves lactose digestion and eliminates symptoms of lactose intolerance. Thus, these cultures clearly fulfil the current concept of probiotics. PMID:16022746

  6. Lactic Acid and Probiotic Bacteria from Fermented and Probiotic Dairy Products

    OpenAIRE

    B.K.L. Karna; Virginia L. Barraquio; O. C. Emata

    2007-01-01

    Lactic acid and probiotic bacteria were enumerated and isolated from commercially available yoghurt andprobiotic milk products. Lactobacillus delbrueckii ssp. bulgaricus were enumerated and isolated usingMRS agar incubated anaerobically at 37oC for 72 hrs. M17 agar was used for the enumeration andisolation of Streptococcus thermophilus incubated aerobically at 37oC for 48 hrs. MRS agar and modifiedMRS agar (MRS + L-cysteine + LiCl + Na propionate) were used for the enumeration and isolation ...

  7. Optimization Of Freeze-Dried Starter For Yogurt By Full Factorial Experimental Design

    OpenAIRE

    Chen He; Niu Jinfeng; Shu Guowei; Wan Hongchang

    2015-01-01

    With the rapidly development of fermented milk product, it is significant for enhancing the performance of starter culture. This paper not only investigated the influence of anti-freeze factors and freeze-drying protective agents on viable count, freeze-drying survival rate and yield of Lactobacillus bulgaricus (LB) and Streptococcus thermophilus (ST), but also optimized the bacteria proportion of freeze-dried starter culture for yogurt by full factorial experimental design. The results showe...

  8. Selection of folate-producing lactic acid bacteria for improving fermented goat milk

    OpenAIRE

    Sanna, Maria Giovanna; Mangia, Nicoletta Pasqualina; Giovanni GARAU; Murgia, Marco Ambrogio; Massa, Tomasina G.; Franco, Mario Andrea; Deiana, Pietrino

    2005-01-01

    Goat milk is a complete food but its low level of folic acid diminisches its nutritional efficacy. In this study, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lb. delbrueckii subsp. lactis and Lb. helveticus strains were selected for folate production in goat milk to improve its quality. A suitable HPLC method was developed to directly determine both total folate and its biologically active derivatives such as 5-methyl-tetrahydrofolate (5- CH3-H4-PteGlu), tetrah...

  9. Crystal Structures and Molecular Dynamics Simulations of Thermophilic Malate Dehydrogenase Reveal Critical Loop Motion for Co-Substrate Binding

    OpenAIRE

    Hung, Chih-Hung; Hwang, Tzann-Shun; Chang, Yu-Yung; Luo, Huei-Ru; Wu, Szu-Pei; Hsu, Chun-Hua

    2013-01-01

    Malate dehydrogenase (MDH) catalyzes the conversion of oxaloacetate and malate by using the NAD/NADH coenzyme system. The system is used as a conjugate for enzyme immunoassays of a wide variety of compounds, such as illegal drugs, drugs used in therapeutic applications and hormones. We elucidated the biochemical and structural features of MDH from Thermus thermophilus (TtMDH) for use in various biotechnological applications. The biochemical characterization of recombinant TtMDH revealed great...

  10. The properties and acceptability of fresh cheese produced using the mixture probiotic culture

    OpenAIRE

    Rajka Božanić; Ljubica Tratnik; Ida Drgalić

    2002-01-01

    Investigation and production of dairy food with probiotic cultures isincreasing due to its health and nutritive benefits. In this paper the probiotic fresh cheese was produced from skim milk samples with 0,1% fat (A) and 1,0% fat (B). Fermentation of skim milk samples was conducted at 40°C by 2% addition of DVS-ABT4 mixture probiotic cultures inoculum with selected bacteria (Lactobacillus acidophilus, Bifidobacterium ssp. and Streptococcus thermophilus) and without rennet addition. After milk...

  11. Effect of green tea supplementation on the microbiological, antioxidant, and sensory properties of probiotic milks

    OpenAIRE

    Najgebauer-Lejko, Dorota

    2014-01-01

    Green tea and its constituents are known for a wide range of health-promoting properties. They may exert antimicrobial action but without altering lactic acid bacteria. The aim of the present study was to estimate the effect of green tea addition on the selected properties of probiotic milks. Bioyogurts (fermented with ABT-1 coculture of Streptococcus thermophilus, Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12) and acidophilus milks (fermented with pure L. acido...

  12. Low-cost fermentative medium for biosurfactant production by probiotic bacteria

    OpenAIRE

    Rodrigues, L. R.; Teixeira, J.A.; Oliveira, Rosário

    2006-01-01

    Potential use of alternative fermentative medium for biosurfactant production by Lactococcus lactis 53 and Streptococcus thermophilus A was studied. Suitable models were established to describe the response of the experiments pertaining to glucose, lactose or sucrose consumption, cell growth and biosurfactant production. Synthetic media MRS and M17 broth were used as control experiments. When the synthetic media were replaced by cheaper alternative media, as cheese whey and molasses, ferme...

  13. Production optimization of probiotic soft cheese made from goat's and cow's milk

    OpenAIRE

    Ida Drgalić; Ljubica Tratnik; Rajka Božanić; Sandra Koruga

    2006-01-01

    The aim of this study was to determine optimal rennet share and fat content in milk for probiotic soft cheeseproduction made from goat's and cow's milk using DVS mixed probiotic culture ABT-4 (Lactobacillus acidophilus, Bifidobacterium spp. and Streptococcus thermophilus), with desirable sensory properties, which will be acceptable by consumers. The best sensory scores had samples of probiotic soft cheese produced in laboratory conditions from milk with 1% of milk fat, pasteurized at 65°C/30 ...

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

    Science.gov (United States)

    Lessard, Christian; Cochu, Armelle; Lemay, Jean-Dominique; Roy, Denis; Vaillancourt, Katy; Frenette, Michel; Moineau, Sylvain; Vadeboncoeur, Christian

    2003-01-01

    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, IIABLMan and IIABHMan, 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. PMID:14617640

  15. Probiotic activity of Lactobacillus delbrueckii subsp. bulgaricus in the oral cavity

    OpenAIRE

    Stamatova, Iva

    2010-01-01

    Yogurt consumption has been related to longevity of some populations living on the Balkans. Yogurt starter L. delbrueckii subsp. bulgaricus and Str. thermophilus have been recognized as probiotics with verified beneficial health effects. The oral cavity emerges as a arget for probiotic applications. Probiotics have demonstrated promising results in controlling dental diseases and oral yeast infections. However, L. bulgaricus despite its broad availability in dairy products has not been evalua...

  16. Competition mechanisms of lactic acid bacteria and bifidobacteria: Fermentative metabolism and colonization

    OpenAIRE

    Tabasco, Raquel; Fernández de Palencia, P.; Fontecha, F. Javier; Peláez, Carmen; Requena, Teresa

    2014-01-01

    Enzyme activities (α- and β-glucosidases, α- and β-galactosidases and β-fructofuranosidase) and organic acid production of four strains of lactic acid bacteria (LAB; Streptococcus thermophilus STY-31, Lactobacillus delbrueckii subsp. bulgaricus LBY-27, Lactobacillus casei LC-01 and Lactobacillus acidophilus LA-5) and Bifidobacterium lactis BB-12 were tested on milk and MRS fermentation broth with glucose, lactose or fructooligosaccharides (FOS) as carbon source. The highest β-galactosidase ac...

  17. Cas9 function and host genome sampling in Type II-A CRISPR–Cas adaptation

    OpenAIRE

    Wei, Yunzhou; Terns, Rebecca M.; Terns, Michael P.

    2015-01-01

    Wei et al. found that Cas9, previously identified as the nuclease responsible for ultimate invader destruction, is also essential for adaptation in Streptococcus thermophilus. Cas9 nuclease activity is dispensable for adaptation. Wei et al. also revealed extensive, unbiased acquisition of the self-targeting host genome sequence by the CRISPR–Cas system that is masked in the presence of active target destruction.

  18. Argonaute of the archaeon Pyrococcus furiosus is a DNA-guided nuclease that targets cognate DNA

    OpenAIRE

    Swarts, Daan C.; Hegge, Jorrit W.; Hinojo, Ismael; Shiimori, Masami; Ellis, Michael A.; Dumrongkulraksa, Justin; Terns, Rebecca M.; Terns, Michael P.; van der Oost, John

    2015-01-01

    Functions of prokaryotic Argonautes (pAgo) have long remained elusive. Recently, Argonautes of the bacteria Rhodobacter sphaeroides and Thermus thermophilus were demonstrated to be involved in host defense. The Argonaute of the archaeon Pyrococcus furiosus (PfAgo) belongs to a different branch in the phylogenetic tree, which is most closely related to that of RNA interference-mediating eukaryotic Argonautes. Here we describe a functional and mechanistic characterization of PfAgo. Like the bac...

  19. Structural insight into negative DNA supercoiling by DNA gyrase, a bacterial type 2A DNA topoisomerase

    OpenAIRE

    Papillon, Julie; Ménétret, Jean-François; Batisse, Claire; Hélye, Reynald; Schultz, Patrick; Potier, Noëlle; Lamour, Valérie

    2013-01-01

    Type 2A DNA topoisomerases (Topo2A) remodel DNA topology during replication, transcription and chromosome segregation. These multisubunit enzymes catalyze the transport of a double-stranded DNA through a transient break formed in another duplex. The bacterial DNA gyrase, a target for broad-spectrum antibiotics, is the sole Topo2A enzyme able to introduce negative supercoils. We reveal here for the first time the architecture of the full-length Thermus thermophilus DNA gyrase alone and in a cl...

  20. Cas9–crRNA ribonucleoprotein complex mediates specific DNA cleavage for adaptive immunity in bacteria

    OpenAIRE

    Gasiunas, Giedrius; Barrangou, Rodolphe; Horvath, Philippe; Siksnys, Virginijus

    2012-01-01

    Clustered, regularly interspaced, short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems provide adaptive immunity against viruses and plasmids in bacteria and archaea. The silencing of invading nucleic acids is executed by ribonucleoprotein complexes preloaded with small, interfering CRISPR RNAs (crRNAs) that act as guides for targeting and degradation of foreign nucleic acid. Here, we demonstrate that the Cas9–crRNA complex of the Streptococcus thermophilus CRISPR3/Cas system in...

  1. Hazelnut milk fermentation using probiotic Lactobacillus rhamnosus GG and inulin

    OpenAIRE

    Bernat Pérez, Neus; Cháfer Nácher, María Teresa; Chiralt Boix, Mª Amparo; González Martínez, María Consuelo

    2014-01-01

    Following the consumer demand of healthy vegetable products due to their interesting nutritional profiles and potential functionalities, the fermentation process of hazelnut milk with Lactobacillus rhamnosus GG and S.thermophilus was studied. The effect of different factors (glucose, inulin and inoculum contents) was analysed to ensure sufficient probiotic survivals in a minimum time. The shelf life of the optimised product was characterised in terms of its main physicochemical and quality pa...

  2. Biochemical Characteristics and Viability of Probiotic and Yogurt Bacteria in Yogurt during the Fermentation and Refrigerated Storage

    OpenAIRE

    F Sarvari; A.M. Mortazavian; M.R. Fazei

    2014-01-01

    This research aimed to investigate the viability of probiotic bacteria (Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) and yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) in yogurt during the fermentation, immediately after fermentation and during refrigerated storage (21 d, 4˚C). Also the biochemical characteristics of milk as affected by the commercial 4-strain mixed starter culture were investigated. Storage time affected the via...

  3. A non-hydrolyzed, fermented milk formula reduces digestive and respiratory events in infants at high risk of allergy

    OpenAIRE

    Dupont, Christophe; Morisset, Martine; Aubert-Jacquin, Cécile; Soulaines, Pascale; Moneret-Vautrin, Denise-Anne

    2010-01-01

    Abstract Objective: To determine the impact of a not hydrolyzed fermented infant formula containing heat-killed Bifidobacterium breve C50 and Streptococcus thermophilus 065 (HKBBST) on the incidence of allergy-like events during the first two years of life in children at high risk of atopy. Methods: This multicenter, randomized, double-blind, controlled study included infants at high risk of atopy. Infants used HKBBST or a standard infant formula (SIF) since birth until 1 year o...

  4. Effect of Bifidobacterium lactis LKM 512 yogurt on fecal microflora in middle to old aged persons

    OpenAIRE

    Matsumoto, Mitsuharu; Tadenuma, Tadashi; Nakamura, Kyoko; Kume, Hitoshi; Imai, Tetsuya; Kihara, Ritsuko; Watanabe, Masatoshi; Benno, Yoshimi

    2011-01-01

    Effect of yogurt (LKM512 yogurt) prepared Bifidobacterium lactis LKM 512, Lactobacillus delbrueckii subsp. bulgaricus LKM 1759 and Streptococcus thermophilus LKM 1742 on fecal microflora in 11 volunteers (six males and five females, average age 76.9 years) given this yogurt 100 g/day for 2 weeks were determined. At week 2 of consumption, the number of bifidobacteria in the fecal microflora increased significantly (p<0.05). Meanwhile, the frequencies of occurrence of peptostreptococci, veil...

  5. Evaluation the Sensory and Probiotics Properties of the Yogurt Supplemented with Carrot Juice

    OpenAIRE

    Carmen R. Pop; Cătălina Topan; Ancuţa M. Rotar; Cristina Semeniuc; Liana Salanţă

    2015-01-01

    This study aimed to develop a new type of yogurt through addition of carrot juice. Yogurt is a fermented milk product obtained from fermentation of Lactobacillus bulgaricus and Streptococcus thermophilus strains. The effect of carrot juice at different levels (0%, 8%, 16%, 24%) on sensory properties and the viability of probiotic bacteria in yogurts during storage (21 days) at refrigerated temperature (4°C) was evaluated. The yogurt supplementation with 24 % carrot juice significantly improve...

  6. Scarce Evidence of Yogurt Lactic Acid Bacteria in Human Feces after Daily Yogurt Consumption by Healthy Volunteers

    OpenAIRE

    del Campo, Rosa; Bravo, Daniel; Cantón, Rafael; Ruiz-Garbajosa, Patricia; García-Albiach, Raimundo; Montesi-Libois, Alejandra; Yuste, Francisco-Javier; Abraira, Victor; Baquero, Fernando

    2005-01-01

    In a double-blind prospective study including 114 healthy young volunteers, the presence in human feces of the yogurt organisms Lactobacillus delbrueckii and Streptococcus thermophilus after repeated yogurt consumption (15 days) was analyzed by culture, specific PCR, and DNA hybridization of total fecal DNA. Detection of yogurt lactic acid bacteria in total fecal DNA by bacterial culture and PCR assay was consistently negative. DNA compatible with yogurt bacteria was found by hybridization ex...

  7. Développement d'un milieu sélectif pour le dénombrement des bifidobactéries dans les laits fermentés

    OpenAIRE

    Bonaparte, Christine; Klein, Günter; Kneifel, Wolfgang; Reuter, Gerhard

    2001-01-01

    International audience Development of a selective culture medium for the enumeration of bifidobacteria in fermented milks. The use of selective culture media is necessary to demonstrate the presence of bifidobacteria in European fermented milks, since Lactobacillus (L.) acidophilus, L. delbrueckii ssp. bulgaricus and Streptococcus (S.) thermophilus usually dominate the flora in these products. But a fully selective medium suppressing these microorganisms does not exist as yet. Therefore, t...

  8. Regulation of bacterial sugar-H+ symport by phosphoenolpyruvate-dependent enzyme I/HPr-mediated phosphorylation

    OpenAIRE

    Poolman, B; Mollet, B; Nieuwenhuis, B; Sulter, G.

    1995-01-01

    The lactose-H+ symport protein (LacS) of Streptococcus thermophilus has a C-terminal hydrophilic domain that is homologous to IIA protein(s) domains of the phosphoenolpyruvate:sugar phosphotransferase system (PTS). C-terminal truncation mutants were constructed and expressed in Escherichia coli and their properties were analyzed. Remarkably, the entire IIA domain (160 amino acids) could be deleted without significant effect on lactose-H+ symport and galactoside equilibrium exchange. Analysis ...

  9. Regulatory RNAs in the Less Studied Streptococcal Species: From Nomenclature to Identification

    Science.gov (United States)

    Zorgani, Mohamed A.; Quentin, Roland; Lartigue, Marie-Frédérique

    2016-01-01

    Streptococcal species are Gram-positive bacteria involved in severe and invasive diseases in humans and animals. Although, this group includes different pathogenic species involved in life-threatening infections for humans, it also includes beneficial species, such as Streptococcus thermophilus, which is used in yogurt production. In bacteria virulence factors are controlled by various regulatory networks including regulatory RNAs. For clearness and to develop logical thinking, we start this review with a revision of regulatory RNAs nomenclature. Previous reviews are mostly dealing with Streptococcus pyogenes and Streptococcus pneumoniae regulatory RNAs. We especially focused our analysis on regulatory RNAs in Streptococcus agalactiae, Streptococcus mutans, Streptococcus thermophilus and other less studied Streptococcus species. Although, S. agalactiae RNome remains largely unknown, sRNAs (small RNAs) are supposed to mediate regulation during environmental adaptation and host infection. In the case of S. mutans, sRNAs are suggested to be involved in competence regulation, carbohydrate metabolism, and Toxin–Antitoxin systems. A new category of miRNA-size small RNAs (msRNAs) was also identified for the first time in this species. The analysis of S. thermophilus sRNome shows that many sRNAs are associated to the bacterial immune system known as CRISPR-Cas system. Only few of the other different Streptococcus species have been the subject of studies pointed toward the characterization of regulatory RNAs. Finally, understanding bacterial sRNome can constitute one step forward to the elaboration of new strategies in therapy such as substitution of antibiotics in the management of S. agalactiae neonatal infections, prevention of S. mutans dental caries or use of S. thermophilus CRISPR-Cas system in genome editing applications. PMID:27507970

  10. Response surface optimization of the medium components for the production of biosurfactants by probiotic bacteria

    OpenAIRE

    L. R. Rodrigues; J.A. Teixeira; Oliveira, Rosário; Mei, Henny van der

    2006-01-01

    Optimization of the medium for biosurfactants production by probiotic bacteria (Lactococcus lactis 53 and Streptococcus thermophilus A) was carried out using response surface methodology. Both biosurfactants were proved to be growth-associated, thus the desired response selected for the optimization was the biomass concentration. The selected factors based on MRS medium for L. lactis 53 growth were peptone, meat extract, yeast extract, lactose, ammonium citrate and KH2PO4. For S. thermophi...

  11. Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria.

    Science.gov (United States)

    Han, Xue; Yang, Zhe; Jing, Xueping; Yu, Peng; Zhang, Yingchun; Yi, Huaxi; Zhang, Lanwei

    2016-01-01

    19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711) were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (p starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture. PMID:27294135

  12. PETROLEUM BIOREFINING FOR POLLUTION PREVENTION

    Energy Technology Data Exchange (ETDEWEB)

    John J. Kilbane II

    2002-03-01

    The objective of this project was to isolate and characterize thermophilic bacterial cultures that can be used for the selective removal of nitrogen, sulfur, and/or metals in the biorefining of petroleum. The project was completed on schedule and no major difficulties were encountered. Significant progress was made on multiple topics relevant to the development of a petroleum biorefining process capable of operating at thermophilic temperatures. New cultures capable of selectively cleaving C-N or C-S bonds in molecules relevant to petroleum were obtained, and the genes encoding the enzymes for these unique biochemical reactions were cloned and sequenced. Genetic tools were developed that enable the use of Thermus thermophilus as a host to express any gene of interest, and information was obtained regarding the optimum conditions for the growth of T. thermophilus. The development of a practical biorefining process still requires further research and the future research needs identified in this project include the development of new enzymes and pathways for the selective cleavage of C-N or C-S bonds that have higher specific activities, increased substrate range, and are capable of functioning at thermophilic temperatures. Additionally, there is a need for process engineering research to determine the maximum yield of biomass and cloned gene products that can be obtained in fed-batch cultures using T. thermophilus, and to determine the best configuration for a process employing biocatalysts to treat petroleum.

  13. Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Xue Han

    2016-01-01

    Full Text Available 19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L and viscosity (7716 mpa/s. Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711 were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (p<0.05. In addition, the yogurt fermented by SH-1 had the lowest syneresis (8.5% and better texture and sensory than the samples fermented by YO-MIX 465 and YF-L711. It manifested that the selected higher exopolysaccharide production starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture.

  14. A selected core microbiome drives the early stages of three popular italian cheese manufactures.

    Directory of Open Access Journals (Sweden)

    Francesca De Filippis

    Full Text Available Mozzarella (M, Grana Padano (GP and Parmigiano Reggiano (PR are three of the most important traditional Italian cheeses. In the three cheese manufactures the initial fermentation is carried out by adding natural whey cultures (NWCs according to a back-slopping procedure. In this study, NWCs and the corresponding curds from M, GP and PR manufactures were analyzed by culture-independent pyrosequencing of the amplified V1-V3 regions of the 16S rRNA gene, in order to provide insights into the microbiota involved in the curd acidification. Moreover, culture-independent high-throughput sequencing of lacS gene amplicons was carried out to evaluate the biodiversity occurring within the S. thermophilus species. Beta diversity analysis showed a species-based differentiation between GP-PR and M manufactures indicating differences between the preparations. Nevertheless, all the samples shared a naturally-selected core microbiome, that is involved in the curd acidification. Type-level variability within S. thermophilus species was also found and twenty-eight lacS gene sequence types were identified. Although lacS gene did not prove variable enough within S. thermophilus species to be used for quantitative biotype monitoring, the possibility of using non rRNA targets for quantitative biotype identification in food was highlighted.

  15. Benzoic Acid Production with Respect to Starter Culture and Incubation Temperature during Yogurt Fermentation using Response Surface Methodology.

    Science.gov (United States)

    Yu, Hyung-Seok; Lee, Na-Kyoung; Jeon, Hye-Lin; Eom, Su Jin; Yoo, Mi-Young; Lim, Sang-Dong; Paik, Hyun-Dong

    2016-01-01

    Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products. PMID:27433115

  16. Fermentation of aqueous plant seed extracts by lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Schafner, D.W.; Beuchat, R.L.

    1986-05-01

    The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

  17. Microbial evolution of traditional mountain cheese and characterization of early fermentation cocci for selection of autochtonous dairy starter strains.

    Science.gov (United States)

    Carafa, Ilaria; Clementi, Francesca; Tuohy, Kieran; Franciosi, Elena

    2016-02-01

    The microbial population of Traditional Mountain (TM) cheese was investigated and characterized for the selection of cocci suitable for developing new starter cultures. Samples of milk, curd and cheese at different ripening times were enumerated in selective culture media and 640 colonies were isolated from curd and cheese after 24 h of ripening. The Lactic Acid Bacteria (LAB) isolated from M17 were clustered into 231 biotypes by RAPD-PCR analysis and identified as Lactococcus lactis, Streptococcus thermophilus and Enterococcus faecalis. Forty percent of enterococci showed the in vitro ability to inhibit raw milk resident coliforms, but they were excluded as possible starters due to the presence of associated risk factors. All lactococci and streptococci were tested for their technological properties; 4 Lc. lactis subsp. lactis and 2 Sc. thermophilus which were fast acidifiers and did not produce unpleasant flavours were subjected to the freeze-drying stability test. Lc. lactis subsp. lactis biotype 68 and Sc. thermophilus biotype 93 showed the best technological properties and may be appropriate for cheese production. This work gave evidence of the high biodiversity of TM-cheese autochthonous biotypes which could be used as starter cultures for the improvement of TM-cheese technology. PMID:26678135

  18. Antimicrobial potential of commercial silver nanoparticles and the characterization of their physical properties toward probiotic bacteria isolated from fermented milk products.

    Science.gov (United States)

    Mikiciuk, Jakub; Mikiciuk, Ewa; Wrońska, Anna; Szterk, Arkadiusz

    2016-01-01

    The application of nanotechnology in the agriculture and food sector is relatively recent compared to its usage in drug delivery or pharmaceuticals. Therefore, this paper presents a study of the effect of silver nanoparticles on probiotic bacteria based on the example of Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Streptococcus thermophilus ST-Y31 isolated from fermented milk products. Probiotic bacteria are one of the most crucial groups of bacteria for the food industry, because of their claimed health-promoting properties. Studies have shown that the type and concentration of silver nanoparticle solutions have a significant impact on the tested probiotic bacteria which are profitable for the digestive system. In the presence of all tested silver nanoparticles, St. thermophilus ST-Y31 growth was inhibited significantly by the dilution method as opposed to the disk-diffusion method. Both the disk-diffusion and the dilution methods showed no significant differences between L. acidophilus LA-5 and B. animalis subsp. lactis BB-12. The concentrations 2 μg mL(-1) and 0.25 μg mL(-1) had the highest antibacterial activity and statistically significant impacts on the tested probiotic strains. To our knowledge, this is the first report on potential antimicrobial effect of nanosilver against the health-promoting probiotic bacteria L. acidophilus LA-5, B. animalis subsp. lactis BB-12 and St. thermophilus ST-Y31 isolated from fermented milk products. PMID:26766747

  19. Microbial community dynamics in thermophilic undefined milk starter cultures.

    Science.gov (United States)

    Parente, Eugenio; Guidone, Angela; Matera, Attilio; De Filippis, Francesca; Mauriello, Gianluigi; Ricciardi, Annamaria

    2016-01-18

    Model undefined thermophilic starter cultures were produced from raw milk of nine pasta-filata cheesemaking plants using a selective procedure based on pasteurization and incubation at high temperature with the objective of studying the microbial community dynamics and the variability in performances under repeated (7-13) reproduction cycles with backslopping. The traditional culture-dependent approach, based on random isolation and molecular characterization of isolates was coupled to the determination of pH and the evaluation of the ability to produce acid and fermentation metabolites. Moreover, a culture-independent approach based on amplicon-targeted next-generation sequencing was employed. The microbial diversity was evaluated by 16S rRNA gene sequencing (V1-V3 regions), while the microdiversity of Streptococcus thermophilus populations was explored by using novel approach based on sequencing of partial amplicons of the phosphoserine phosphatase gene (serB). In addition, the occurrence of bacteriophages was evaluated by qPCR and by multiplex PCR. Although it was relatively easy to select for a community dominated by thermophilic lactic acid bacteria (LAB) within a single reproduction cycle, final pH, LAB populations and acid production activity fluctuated over reproduction cycles. Both culture-dependent and -independent methods showed that the cultures were dominated by either S. thermophilus or Lactobacillus delbrueckii subsp. lactis or by both species. Nevertheless, subdominant mesophilic species, including lactococci and spoilage organisms, persisted at low levels. A limited number of serB sequence types (ST) were present in S. thermophilus populations. L. delbrueckii and Lactococcus lactis bacteriophages were below the detection limit of the method used and high titres of cos type S. thermophilus bacteriophages were detected in only two cases. In one case a high titre of bacteriophages was concurrent with a S. thermophilus biotype shift in the culture

  20. Influence of stevioside and rebaudioside A on fermentation bacterium in food%甜菊甙及A3甙对食品发酵菌的影响研究

    Institute of Scientific and Technical Information of China (English)

    钱丽丽; 范雪峰; 孙丽建; 张丽萍

    2011-01-01

    试验主要研究了甜菊总甙与A3甙这两种甜味剂对嗜热链球菌、植物乳杆菌和酿酒酵母的影响,受试菌选择以食品常用发酵菌为研究对象,在MRS和YPD培养基中添加不同量的甜菊甙和A3甙,测定各受试菌在甜菊甙和A3甙不同浓度下的生长曲线,同时做对照试验.受试菌的生长曲线测定方法采用比浊法,测定波长植物乳杆菌、嗜热链球菌为600nm,酿酒酵母为560nm.结果表明甜菊甙及A3甙对植物乳杆菌和酿酒酵母的生长影响作用不明显,对嗜热链球菌表现为双重影响,在低浓度0.01%~0.1%的甜菊甙和A3甙添加组对该菌生长有促进作用,而在甜菊甙和A3甙浓度0.5%~1%时则表现抑制生长作用,甜菊甙和A3甙之间对嗜热链球菌生长曲线影响无显著差异.通过研究,初步探究了发酵食品中添加这两种甜味剂对三种发酵菌生长情况的影响.%This paper studied how stevioside and rebaudiodside A - two kinds of food sweetener affect the growth of streptococcus thermophilus, lactobacillus plantarum and saccharomyces cerevisiae. Common food fermentation bacterium was selected in the study. Stevioside and rebaudiodside A with different amount were added to MRS broth and YPD broth cultured bacterium, and the growth of bacteria under different concentration was compared with the controlled trial. The determination method is turbidimetry at the wavelength of 600nm for streptococcus thermophilus, lactobacillus,and 560nm for saccharomyces cerevisiae. The results indicated that stevioside and rebaudiodside A have not significantly affected the growth of lactobacillus plantarum and saccharomyces cerevisiae; however, they showed two different effects on streptococcus thermophilus growth: at low concentration (0. 01% ~ 0. 5 % ), it promoted the growth of streptococcus thermophilus, while at higher concentration of more than 0. 5%, it inhibited the grow of streptococcus thermophilus. There was no obvious

  1. Development of a fermented ice-cream as influenced by in situ exopolysaccharide production: Rheological, molecular, microstructural and sensory characterization.

    Science.gov (United States)

    Dertli, Enes; Toker, Omer S; Durak, M Zeki; Yilmaz, Mustafa T; Tatlısu, Nevruz Berna; Sagdic, Osman; Cankurt, Hasan

    2016-01-20

    This study aimed to investigate the role of in situ exopolysaccharide (EPS) production by EPS(+)Streptococcus thermophilus strains on physicochemical, rheological, molecular, microstructural and sensory properties of ice cream in order to develop a fermented and consequently functional ice-cream in which no stabilizers would be required in ice-cream production. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 32, 37 and 42 °C and time; 2, 3 and 4h) on pH, S. thermophilus count, EPS amount, consistency coefficient (K), and apparent viscosity (η50) were investigated and optimized using single and multiple response optimization tools of response surface methodology. Optimization analyses indicated that functional ice-cream should be fermented with strain 1 or strain mixture at 40-42 °C for 4h in order to produce the most viscous ice-cream with maximum EPS content. Optimization analysis results also revealed that strain specific conditions appeared to be more effective factor on in situ EPS production amount, K and η50 parameters than did fermentation temperature and time. The rheological analysis of the ice-cream produced by EPS(+) strains revealed its high viscous and pseudoplastic non-Newtonian fluid behavior, which demonstrates potential of S. thermophilus EPS as thickening and gelling agent in dairy industry. FTIR analysis proved that the EPS in ice-cream corresponded to a typical EPS, as revealed by the presence of carboxyl, hydroxyl and amide groups with additional α-glycosidic linkages. SEM studies demonstrated that it had a web-like compact microstructure with pores in ice-cream, revealing its application possibility in dairy products to improve their rheological properties. PMID:26572373

  2. Effect of bacteria proportion on the fermentation of goat yoghurt with probiotic culture

    Directory of Open Access Journals (Sweden)

    Guowei Shu

    2015-12-01

    Full Text Available Background. Goat milk production in Shaanxi province is dominant in China, but the product is mainly in- fant formula and adult milk powder; product homogeneity is serious and has no goat yoghurt with probiotic culture. Methods. The effect of bacteria proportion (1:3:1, 1:2:1, 1:1:1, 2:1:1, 3:1:1 on pH, acidity, and viable counts and sensory evaluation of goat milk fermented by probiotics including L. acidophilus, B. bifidum  or L. casei besides, S. thermophilus and L. bulgaricus for developing AB-goat yoghurt and BC-goat yoghurt was investigated. Results. The optimum bacteria proportion of L. acidophilus : B. bifidum : S. thermophilus and L. bulgaricus for AB-goat yoghurt and B. bifidum : L. casei : S. thermophilus and L. bulgaricus for BC-goat yoghurt were both 2:1:1. The pH, acidity, the viable counts of L. acidophilus and B. bifidum, the total viable counts were respectively 4.60, 7.73 (g/L, 3.50×107 cfu/mL, 3.40×107 cfu/mL and 2.30×109 cfu/mL in AB-goat yoghurt. The pH, acidity, the viable counts of B. bifidum and L. casei, the total viable counts were respectively  4.61, 8.16 (g/L, 7.60×107 cfu/mL, 5.60×107 cfu/mL and 2.04×109 cfu/mL in BC-goat yoghurt. Conclusion. The bacteria proportion had a significant effect on fermentation of AB- and BC-goat yoghurt, the results are beneficial for developing AB-goat yoghurt and BC-goat yoghurt.

  3. The evaluation of mixtures of yeast and potato extracts in growth media for biomass production of lactic cultures.

    Science.gov (United States)

    Gaudreau, H; Renard, N; Champagne, C P; Van Horn, D

    2002-07-01

    The effectiveness of yeast extracts (YE) and potato extracts (PE) to promote growth of seven lactic cultures was evaluated by automated spectrophotometry (AS). Two aspects of the growth curve were analysed: (1) maximum biomass obtained (using ODmax) and (2) highest specific growth rate mu(max)) Eleven lots from the same PE-manufacturing process were examined for lot-to-lot variability. The ODmax values of three of the seven strains were significantly affected by lot source, but mu(max) was not significantly affected. The growth of bacteria was systematically lower in base medium containing 100% PE than in base medium containing 100% YE for both ODmax or mu(max) data, which could be related to the lower content in nitrogen-based compounds in PE. In AS assays, highest OD values for Lactobacillus casei EQ28, Lactobacillus rhamnosus R-011, Lactobacillus plantarum EQ12, and Streptococcus thermophilus R-083 were obtained with a mixture of PE and YE. Fermentations (2 L) were also carried out to determine the accuracy of AS to predict biomass levels obtained under fermentation trials. In these fermentations, replacement of 50% YE with PE was shown to enable good growth of S. thermophilus. With L. rhamnosus R-011, a high correlation (R2 = 0.95) was found between ODmax data obtained in the AS assays and that of the 2-L bioreactor when the same growth medium was used for both series of fermentations. However, AS was not as efficient when industrial media were used for the bioreactor assays. The relationship was still good for ODmax between AS data and that of the bioreactor data with L. rhamnosus R-011 in industrial LBS medium (R2 = 0.87), but was very poor with the S. thermophilus R-083 on Rosell #43 industrial medium (R2 = 0.33). Since PE cost 40% less than YE, there are strong economic advantages in considering such a partial replacement of YE by PE. PMID:12224561

  4. A culture-dependent survey of thermophilic bacteria from hot springs in Xiamen area in China

    Institute of Scientific and Technical Information of China (English)

    YANG Bo; OUYANG Jianping; AO Jingqun; CHEN Xinhua

    2009-01-01

    Microbes are believed to play important roles in ecosystem function in many environments. The hot springs of Xiamen Island are close to the Xiamen Sea, and may have some characteristics different from those of inland hot springs. Microbes living in the hot springs of Xiamen may have new characteristics. However, little is known about microbial communities of hot springs close to the Xiamen Sea. A cuhure-dependent survey of microbial population in the Xiamen hot springs was pcrformed by using an approach combining total cellular protein profile identification and 16S rRNA gene sequencing. A total of 328 isolates of bacteria were obtained from liquid and sediment samples from the Xiamen hot springs, including neutrophilie thermophilic bacteria and moderately thermophilic acidophiles. Neutrophilic thermophilic bacteria, which grow at a temperature range of 55-90℃ including Rhodothermus marinus (Strain 1) , Thermus thermophilus (Strain 2), Thermus thiopara (Strain 3) , Geobacillus stearothermophilus(Strain 4) , Geobacillus thermoleovorans (Strain 5) , and Pseudomonas pseudoal-caligenes (Strain 6), were recovered by 2216E plates. Moderately thermophilic acidophiles, which can grow at temperatures above 50℃ and a pH range of 1. 8-3.5 such as Alicyclobacillus acidoterrestris (Strain 8) , Sul-fobacillus acidophilus (Strain 9), and Sulfobacillus thermosulfidooxidans (Strain 10), were isolated on selective solid medium containing sulfur and Fe2+. Among these strains, Rhodothermus marinus, Thermus thermophilus and Geobacillus stearothermophilus are not only thermophilcs, but also halophiles. One bacterium strain (Strain 6) shared 99% nucleotide sequence homology with Pseudomonas pseudoalcaligenes on the 16S rRNA gene se-quence, but was quite different from Pseudomonas pseudoalcaligenes in biological characteristics, suggesting that it may represent a novel thermophilic species. Results indicated that various species of neutrophilic thermophiles and moderately thermophilic

  5. Aceitação sensorial e caracterização de frozen yogurt de leite de cabra com adição de cultura probiótica e prebiótico Sensorial acceptance and characterization of goat's milk frozen yogurt with addition of probiotic culture and prebiotic

    OpenAIRE

    Larissa Lima Alves; Neila Silvia Pereira dos Santos Richards; Larissa Vargas Becker; Diego Fontana de Andrade; Liana Inês Guidolin Milani; Ana Paula de Souza Rezer; Gustavo Callegari Scipioni

    2009-01-01

    O leite de cabra é recomendado para pessoas intolerantes ao leite de vaca e/ou portadoras de desordens gastrintestinais. frozen yogurt elaborado a partir de iogurte de leite de cabra foi acrescido de 1% de prebiótico (inulina), 0,25% de cultura starter (Streptococcus thermophilus e Lactobacillus bulgaricus) e 0,25% de cultura probiótica (Bifidobacterium animalis e Lactobacillus acidophilus) para verificar seu potencial probiótico (após sete e 120 dias de armazenamento), sua qualidade físico-q...

  6. Adenosine Triphosphate Stimulates Aquifex aeolicus MutL Endonuclease Activity

    OpenAIRE

    Jerome Mauris; Thomas C Evans

    2009-01-01

    BACKGROUND: Human PMS2 (hPMS2) homologues act to nick 5' and 3' to misincorporated nucleotides during mismatch repair in organisms that lack MutH. Mn(++) was previously found to stimulate the endonuclease activity of these homologues. ATP was required for the nicking activity of hPMS2 and yPMS1, but was reported to inhibit bacterial MutL proteins from Thermus thermophilus and Aquifex aeolicus that displayed homology to hPMS2. Mutational analysis has identified the DQHA(X)(2)E(X)(4)E motif pre...

  7. Röntgenstrukturanalyse von LytB aus Aquifex aeolicus und Plasmodium falciparum

    OpenAIRE

    Rekittke, Ingo

    2010-01-01

    Der MEP-Weg stellt auf Grund seiner besonderen Eigenschaften ein interessantes Ziel für die de novo Entwicklung antimikrobialer und herbizider Wirkstoffe dar. Mit Ausnahme der letzten beiden Enzyme GcpE und LytB ist der MEP-Weg schon strukturell geklärt. Um diese Lücke zu schliessen, wurden in dieser Arbeit Kristallisationsexperimente mit Aquifex aeolicus und Plasmodium falciparum LytB und Thermus thermophilus GcpE durchgeführt. Durch die im Rahmen dieser Arbeit durchgeführten Experimente ...

  8. Dicty_cDB: Contig-U11162-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) Kuenenia stuttgartiensis genome f... 137 1e-30 AE014613...r violaceus PCC 7421 D... 134 7e-30 U57757_1( U57757 |pid:none) Treponema pallidum PolA gene, partial ... 13...s ... 133 2e-29 AJ238760_2( AJ238760 |pid:none) Rickettsia montana ftsY (partial)...i 12J chromos... 131 6e-29 BX897699_6( BX897699 |pid:none) Bartonella henselae strain...) Neisseria meningitidis 053442, c... 129 2e-28 EU708319_1( EU708319 |pid:none) Thermus thermophilus strain

  9. Typing some of lactic acid bacteria in Syria using PCR and FT-IR techniques

    International Nuclear Information System (INIS)

    Lactic Acid Bacteria (LAB) are considered to be the most useful microorganisms. They are beneficial in flavoring foods, inhibiting pathogenic as well as spoilage bacteria in food products. The isolates of LAB were obtained from traditional Syrian dairy products (white cheese and curdled yogurt) obtained from different regions in Syria. The isolates were subjected to phenotypic characterization analyses. The PCR technique of bacterial DNA was evaluated as an advanced tool for the identification of LAB. It was found that strains: E. faecium, E. faecalis and S. thermophilus dominate in white cheese and in yogurt. Our results demonstrated that we could identify LAB using Fourier transform infrared spectroscopy (FT-IR) patterns. (Authors)

  10. Mechanism of CuA assembly

    OpenAIRE

    Luciano A Abriata; Banci, Lucia; Bertini, Ivano; Ciofi-Baffoni, Simone; Gkazonis, Petros; Spyroulias, Georgios A.; Alejandro J. Vila; Wang, Shenlin

    2008-01-01

    Copper is essential for proper functioning of cytochrome c oxidases, and therefore for cellular respiration in eukaryotes and many bacteria. Here we show that a new periplasmic protein (PCuAC) selectively inserts Cu(I) ions into subunit II of Thermus thermophilus ba3 oxidase to generate a native CuA site. The purported metallochaperone Sco1 is unable to deliver copper ions; instead, it works as a thiol-disulfide reductase to maintain the correct oxidation state of the CuA cysteine ligands.

  11. Identification of lactic acid bacteria isolated from Tarhana, a traditional Turkish fermented food

    DEFF Research Database (Denmark)

    Sengun, Ilkin Yucel; Nielsen, Dennis Sandris; Karapinar, Mehmet;

    2009-01-01

    Tarhana is a traditional fermented product produced from a mixture of spontaneously fermented yogurt and wheat flour in Turkey. The aims of the present study were to enumerate and identify for the first time by molecular biology-based methods predominant lactic acid bacteria (LAB) isolated during...... processing of Tarhana. Samples were collected from eight different regions of Turkey. In order to explore the relationship between raw material and the microbiology of Tarhana, yogurt and wheat flour were also analyzed. A total of 226 Gram-positive and catalase-negative isolates were obtained from MRS, M17...... and S. thermophilus was found to be the yogurt....

  12. Procedimiento para la detección e identificación simultánea y específica de bacterias lácticas y bifidobacterias en leches fermentadas y en cultivos iniciadores para leches fermentadas

    OpenAIRE

    Tabasco Rentero, Raquel; Paarup, Torsten; Janer Otero, Carolina; Peláez Martínez, María Carmen; Requena Rolanía, María Teresa

    2006-01-01

    Procedimiento para la detección e identificación simultánea y específica de bacterias lácticas y bifidobacterias en leches fermentadas y en cultivos iniciadores para leches fermentadas. El procedimiento permite la rápida y simultánea detección e identificación de diferentes especies de bacterias lácticas (S. thermophilus, L. bulgaricus, L. casei, L. acidophilus) en cultivos mixtos con B. lactis, especies habitualmente presentes en yogur y leches fermentadas que contien...

  13. Dicty_cDB: Contig-U12254-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 000880_1391( CP000880 |pid:none) Salmonella enterica subsp. ariz... 204 6e-51 CP0...ubsp. ... 203 1e-50 CP000026_1250( CP000026 |pid:none) Salmonella enterica subsp. ente... 203 2e-50 BX571662... CP000024 |pid:none) Streptococcus thermophilus CNRZ1... 201 5e-50 AE017220_1528( AE017220 |pid:none) Salmonella enterica subsp. ente... ... 116 2e-24 AM933173_2393( AM933173 |pid:none) Salmonella enterica subsp. ente... 116 2e-24 CP000383_2164...) Database: CSM 6905 sequences; 5,674,871 total letters Score E Sequences producing significant alignment

  14. ПОКАЗАТЕЛИ КАЧЕСТВА СМЕСИ КИСЛОМОЛОЧНОГО МОРОЖЕНОГО

    OpenAIRE

    Ахмедова, В.; Рябцева, С.

    2013-01-01

    Исследование было проведено путем сквашивания смеси кисломолочного мороженого различными комбинациями культур: L. acidophilus, St. thermophilus, L. casei+ St. thermophilus, L. bulgaricus+ St. thermophilus, Lac. spp + St. thermophilus, симбиотическая закваска на основе кефирных грибков. Бактериальные закваски вносили в смесь в количестве 5%, после чего экспериментальные образцы подвергались физико-химической и органолептической оценки. Среди представленных образцов высокую оценку по показателя...

  15. Utilización de inulina en la formulación de yogur descremado de leche de cabra Using inulin in the formulation of non-fat goats´milk yogurt

    OpenAIRE

    Enzo Goncalvez de Oliveira; Noelia F Paz; Erica N Budde; Andrea P Cravero; Adriana N Ramón

    2012-01-01

    La inulina es una fibra prebiótica que imparte mayor cremosidad y favorece la textura y firmeza en productos lácteos. El objetivo de este trabajo fue utilizarla para reemplazar la grasa en la formulación de un yogur descremado de leche de cabra, de consistencia batida. Para ello se utilizó: leche de cabra biotipo Saanen; cultivos de bacterias lácticas liofilizadas: Streptococcus thermophilus (ST M6) y Lactobacillus delbrueckii subsp. bulgaricus (Lb-12); inulina en polvo; azúcar, gelatina sin ...

  16. Estudio microbiológico comparativo de yogur fresco y termizado en un modelo animal in vivo Comparative microbiological study of fresh and heat-treated yoghurt in an in vivo animal model

    OpenAIRE

    J. E. García de los Ríos; J. Santos Jiménez Gómez; P. A. Jiménez Gómez; M.ª P. Reche Sainz; F. Álvarez Dávila; A. M.ª Rojas Mendoza

    2003-01-01

    En un ensayo agudo, ratas en ayunas de 24 h fueron sondadas con 2 ml de yogur fresco, yogur termizado o agua destilada, y se sacrificaron a las 2, 4, 8 y 24 h después, siendo comparadas con ratas sin sondar. Se determinó la supervivencia de las bacterias lácticas del yogur administrado en estómago e intestinos de los animales, y si las bacterias aisladas tenían el perfil de las cepas de Lactobacillus delbrueckii subsp. bulgaricus y Streptococcus thermophilus aisladas originalmente del yogur. ...

  17. Cas5d processes pre-crRNA and is a member of a larger family of CRISPR RNA endonucleases

    OpenAIRE

    Garside, Erin L.; Schellenberg, Matthew J.; Gesner, Emily M.; Bonanno, Jeffrey B.; Sauder, J. Michael; Burley, Stephen K.; Almo, Steven C.; Mehta, Garima; MacMillan, Andrew M.

    2012-01-01

    A detailed functional analysis of the CRISPR-associated Thermus thermophilus Cas5d protein identifies it as a sequence-specific pre-crRNA processing endonuclease. High-resolution X-ray structural studies of a second Cas5d ortholog highlight similarities with previously characterized CRISPR processing enzymes. A combination of structural and functional analyses based on these results allow a modeling of the interaction of Cas5d with its RNA substrate and suggest that it is a member of a larger...

  18. The influence of heme ruffling on spin densities in ferricytochromes c probed by heme core 13C NMR

    OpenAIRE

    Kleingardner, Jesse G.; Bowman, Sarah E. J.; Bren, Kara L.

    2013-01-01

    The heme in cytochromes c undergoes a conserved out-of-plane distortion known as ruffling. For cytochromes c from the bacteria Hydrogenobacter thermophilus and Pseudomonas aeruginosa, NMR and EPR spectra have been shown to be sensitive to the extent of heme ruffling and to provide insights into the effect of ruffling on electronic structure. Using mutants of each of these cytochromes that differ in the amount of heme ruffling, NMR characterization of the low-spin (S=1/2) ferric proteins has c...

  19. Probiotics.

    Science.gov (United States)

    Kligler, Benjamin; Cohrssen, Andreas

    2008-11-01

    Probiotics are microorganisms with potential health benefits. They may be used to prevent and treat antibiotic-associated diarrhea and acute infectious diarrhea. They may also be effective in relieving symptoms of irritable bowel syndrome, and in treating atopic dermatitis in children. Species commonly used include Lactobacillus sp., Bifidobacterium sp., Streptococcus thermophilus, and Saccharomyces boulardii. Typical dosages vary based on the product, but common dosages range from 5 to 10 billion colony-forming units per day for children, and from 10 to 20 billion colony-forming units per day for adults. Significant adverse effects are rare, and there are no known interactions with medications. PMID:19007054

  20. Growth of ABT-5 bacteria culture in whey supplemented with whey protein concentrate

    OpenAIRE

    Bojan Matijević; Rajka Božanić; Ljubica Tratnik

    2010-01-01

    The objective of this research was to decrease the duration of whey fermentation and to analyze the impact of whey protein concentrates (WPC) addition on growth and activity as well as on survival of mixed ABT-5 culture bacteria (Lactobacillus acidophilus, Bifidobacterium spp. and Streptococcus thermophilus) during 28 days of fermented whey cold storage (5 °C). Whey fermentation was observed at 37 °C with and without 1.5 and 3 % WPC addition. Whey fermentation with mixed ABT-5 bacterial cultu...

  1. La cinétique microbienne et d’acidité du yaourt associé aux huiles essentielles Ammoïdes verticillata et Thymus ciliatus

    OpenAIRE

    ZAHDOUR, MANEL

    2016-01-01

    Les huiles essentielles renferment plusieurs constituants qui sont bénéfiques pour le corps humain. Cependant il est difficile de les consommer directement. Pour cette raison on a étudié leurs effet sur vecteur alimentaire tel que le yaourt. Ce dernier en le préparant, on ajoute l’huile essentielle de Thymus ciliatus et d’ Ammoïdes verticullata avec des concentrations de 0.3 et 0.6%, pour compter le nombre des bactéries lactiques (Streptococcus thermophilus et Lactobacillus bul...

  2. DETERMINATION OF QUALITY PROPERTIES OF DIET ACIDOPHILUS BIFIDUS YOGHURT AND DIET YOGHURT

    Directory of Open Access Journals (Sweden)

    Oğuz GÜRSOY

    1999-03-01

    Full Text Available Diet yoghurt and diet Asidophilus bifidus yoghurt were produced from cow milk and fat ratio was decreased below 1 %. In production of diet Asidophilus bifidus yoghurt, freeze dried DVS culture which contains normal yoghurt bacteria (Streptococcus thermophilus ve Lactobacillus delbrueckii subsp. bulgaricus and therapeutic lactic acid bacteria (Lactobacillus acidophilus and Bifidobacteria was used. In production of diet yoghurt, normal yoghurt bacteria were used. Chemical, microbiological and sensory properties of these products were determined and compared. Generally, except the consistency sensed in mouth, chemical, microbiological and sensory properties were approximately same. Finally, these products were healthier than other yoghurt products, because of the amount of low fat and containing therapeutic bacteria.

  3. Fizikalno-kemijske, teksturne i senzorne značajke probiotičkoga jogurta pripremljenog od naklijalog zrnja soje

    OpenAIRE

    Yang, Mei; Li LI

    2010-01-01

    U ovom su radu, pomoću probiotičkih sojeva Lactobacillus helveticus B02, Streptococcus thermophilus IFFI 6038 i Lactobacillus bulgaricus AS1.1482, fermentacijom na 42 °C tijekom 4 sata, pripremani jogurti od mlijeka dobivenog iz naklijalog zrnja soje [Glycine max (L.) Merrill], različite dužine hipokotila. Ispitane su fizikalno-kemijske, teksturne i senzorne značajke dobivenih proizvoda. Rezultati su pokazali da je jogurt dobiven iz naklijalog zrnja soje dužine hipokotila od 3 cm imao manju p...

  4. The Incidence of Necrotizing Enterocolitis Is Increased Following Probiotic Administration to Preterm Pigs

    DEFF Research Database (Denmark)

    Cilieborg, Malene Skovsted; Thymann, Thomas; Siggers, Richard;

    2011-01-01

    Preterm birth and necrotizing enterocolitis (NEC) is associated with inappropriate gut colonization and immunity, which may be improved by probiotic bacteria. Using a preterm pig model of NEC, we investigated the effects of probiotics on intestinal structure, function, microbiology, and immunology...... in the immediate postnatal period. Just after birth, caesarean-delivered preterm pigs were inoculated with Lactobacillus paracasei, Bifidobacteria animalis, and Streptococcus thermophilus (total 2.4 x 1010/d) either as live (ProLive, n = 14) or gamma-irradiated dead bacteria (ProDead, n = 12) and...

  5. 不同添加剂对冷藏期酸奶品质和活菌数的影响%The effects of different additives on the quality and active cell count of sour milk during the period of cold storage

    Institute of Scientific and Technical Information of China (English)

    韩向红; 黄吟; 王锐萍; 何滨

    2003-01-01

    该试验采用嗜热链球菌(Streptococcus thermophilus)和保加利亚乳杆菌(Lactobacillus balgaricus)作为混合菌剂对乳液及分别加入不同添加剂的乳液进行酸奶发酵,发现所添加的添加剂均可促进产酸并提高冷藏期酸奶的品质和活菌数,其中以胡萝卜汁效果最好.

  6. Influence of Pollen, Chia Seeds and Cranberries Addition on the Physical and Probiotics Characteristics of Yogurt

    Directory of Open Access Journals (Sweden)

    Carmen Pop

    2015-05-01

    Full Text Available Yoghurt is a fermented milk product obtained from fermentation of Lactobacillus bulgaricus and Streptococcus thermophilus strains. The effect of bee pollen, chia seeds and cranberries on the viability of probiotic bacteria in yogurts during storage (21 days at refrigerated temperature (4°C was evaluated. The yogurt supplementation with 1,4 % chia seeds and 7,6% cranberries significantly improves the stability of the lactic acid bacteria, that contained the recommended levels of (106–107 cfu/g probiotic bacteria at the end of 21-day shelf life.

  7. Molecular basis of dihydrouridine formation on tRNA

    OpenAIRE

    Yu, Futao; Tanaka, Yoshikazu; Yamashita, Keitaro; Suzuki, Takeo; Nakamura, Akiyoshi; Hirano, Nagisa; Suzuki, Tsutomu; Yao, Min; Tanaka, Isao

    2011-01-01

    Dihydrouridine (D) is a highly conserved modified base found in tRNAs from all domains of life. Dihydrouridine synthase (Dus) catalyzes the D formation of tRNA through reduction of uracil base with flavin mononucleotide (FMN) as a cofactor. Here, we report the crystal structures of Thermus thermophilus Dus (TthDus), which is responsible for D formation at positions 20 and 20a, in complex with tRNA and with a short fragment of tRNA (D-loop). Dus interacts extensively with the D-arm and recogni...

  8. Proteolytic and ACE-inhibitory activities of probiotic yogurt containing non-viable bacteria as affected by different levels of fat, inulin and starter culture

    OpenAIRE

    Shakerian, Mansour; Razavi, Seyed Hadi; Ziai, Seyed Ali; Khodaiyan, Faramarz; Yarmand, Mohammad Saeid; Moayedi, Ali

    2013-01-01

    In this study, the effects of fat (0.5 %, 3.2 % and 5.0 %), inulin (0.0 and 1.0 %) and starter culture (0.0 %, 0.5 %, 1.0 % and 1.5 %) on the angiotensin converting enzyme (ACE)-inhibitory activity of probiotic yogurt containing non-viable bacteria were assessed. Proteolytic activities of bacteria were also investigated. Yogurts were prepared either using a sole yogurt commercial culture including Streptococcus thermophilus and Lactobacillus delbrueckii subs. bulgaricus or bifidobacterium ani...

  9. Sensory Evaluation of the Strawberry Flavored Yoghurt with Stevia and Sucrose Addition

    OpenAIRE

    Lisak, Katarina; Lenc, Maja; Jeličić, Irena; Božanić, Rajka

    2012-01-01

    As obesity is a growing problem in the world the target of food industries is to produce low calorie products safe for the human health. According to the non-caloric value of stevia and its beneficial influence on human health, there is a great possibility of its use in the food industry. Plain yoghurts were produced by fermentation with ABT-5 cultures (Lactobacillus acidophilus, Streptococcus thermophilus and Bifi dobacterium spp.) and flavored by addition of 0.2 mL/100 g strawberry aroma. Y...

  10. Antibiotic susceptibility of strains in Chinese medical probiotic products

    Institute of Scientific and Technical Information of China (English)

    TANG Huan; YUAN Jing; XIE Cai-hong; WEI Hong

    2007-01-01

    Objective:To investigate the susceptibility of strains separated from probiotic products for medical purpose to 14 antimicrobial agents. Methods:The single aerobic strains were isolated from these products respectively and disc agar diffusion assay was proceeded to determine the susceptibility. Results:Probiotics tested in the study mostly showed multiresistant to the agents. Lactobacillus acidophilus LAP,LAB, Lactobacillus bulgaricus LBJ and Streptococcus thermophilus STJ were resistant to vancomycin. Conclusion: Drug resistance exists in most of commercial probiotics. The evaluation and monitoring of safety of probiotic products for medical purpose should be paid great attention.

  11. STUDY OF GUSTATORY AND STRUCTURAL PROPERTIES OF KEFIR PRODUCT

    OpenAIRE

    MILENA H. MOMCHILOVA; GERGANA B. IVANOVA; AKSENIYA ATANASOVA; NEVENKA RUMYAN; NELLY V. GEORGIEVA

    2012-01-01

    The subject of the study is the improvement of Kefir culture. For this investigation it was used Kefir culture and two series of experiments were carried out. Yeasts from probiotic strain Saccharomyces boulardii were added in the first series and the lactic acid bacteria (LAB) of Streptococcus thermophilus strain, with a polysaccharide activity were added to Kefir culture in the second series. The fermentation conditions were 30°C, duration 16 hours and cooling 4 hours up to 4°C. The characte...

  12. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

    2015-01-01

    Ammonia-rich substrates can cause inhibition on anaerobic digestion process. Syntrophic acetate oxidizing bacteria (SAOB) and hydrogenotrophic methanogens are important for the ammonia inhibitory mechanism on anaerobic digestion. The roles and interactions of SAOB and hydrogenotrophic methanogens...... to ammonia inhibition effect are still unclear. The aim of the current study was to determine the ammonia toxicity levels of various pure strains of SAOB and hydrogenotrophic methanogens. Moreover, ammonia toxicity on the syntrophic cultivated strains of SAOB and hydrogenotrophic methanogens was...... tested. Thus, four hydrogenotrophic methanogens (i.e. Methanoculleus bourgensis, Methanobacterium congolense, Methanoculleus thermophilus and Methanothermobacter thermautotrophicus), two SAOB (i.e. Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) and their syntrophic cultivation, were...

  13. of intestinal microflora” pursuant to Article 14 of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    of a health claim related to a combination of Lactobacillus delbrueckii subsp. bulgaricus AY/CSL (LMG P-17224) and Streptococcus thermophilus 9Y/CSL (LMG P-17225) and “beneficial modulation of intestinal microflora”. The scope of the application was proposed to fall under a health claim referring to children...... microflora”. The target population, as proposed by the applicant, is children from 3 months to 14 years old. No evidence has been provided by the applicant to establish that the claimed effect, “beneficial modulation of the intestinal microflora”, is a beneficial physiological effect. The Panel concludes...... of the intestinal microflora”. © European Food Safety Authority, 2011...

  14. Typing some of lactic acid bacteria in Syria using PCR and FT-IR techniques

    International Nuclear Information System (INIS)

    Lactic Acid Bacteria (LAB) are considered to be the most useful microorganisms. They are beneficial in flavoring foods, inhibiting pathogenic as well as spoilage bacteria in food products. The isolates of LAB were obtained from traditional Syrian dairy products (white cheese and curdled yogurt) obtained from different regions in Syria. The isolates were subjected to phenotypic characterization analyses. The PCR technique of bacterial DNA was evaluated as an advanced tool for the identification of LAB. It was found that strains: E. faecium, E. faecalis and S. thermophilus dominate in white cheese and in yogurt. Our results demonstrated that we could identify LAB using Fourier transform infrared spectroscopy (FT-IR) patterns. (author)

  15. Application of the extracellular alpha-amylase gene from Streptococcus bovis 148 to construction of a secretion vector for yogurt starter strains.

    Science.gov (United States)

    Satoh, E; Ito, Y; Sasaki, Y; Sasaki, T

    1997-11-01

    Streptococcus thermophilus ATCC 19258, Lactobacillus delbrueckii subsp. bulgaricus T-11, and Lactococcus lactis subsp. lactis IL1403 were transformed with the alpha-amylase gene (amyA) from Streptococcus bovis 148 by using a wide host-range vector, and all the transformants secreted the alpha-amylase successfully. Since the promoter and the secretion signal of the amyA gene were functional in these strains, we constructed a secretion vector using the expression elements of amyA. Trials to secrete foreign enzymes in yogurt starter strains were performed using this novel secretion vector. PMID:9361445

  16. Crystal structures at 2.5 Angstrom resolution of seryl-tRNA synthetase complexed with two analogs of seryl adenylate

    DEFF Research Database (Denmark)

    Belrhali, H.; Yaremchuk, A.; Tukalo, M.; Larsen, K.; Berthet-Colominas, C.; Leberman, R.; Beijer, B.; Sproat, B.; Als-Nielsen, J.; Grübel, G.; Legrand, J.-F.; Lehmann, M.; Cusack, S.

    1994-01-01

    crystal from adenosine triphosphate (ATP) and serine hydroxamate, and the second is with a synthetic analog of seryl adenylate (5'-O-[N-(L-seryl)-sulfamoyl]adenosine), which is a strong inhibitor of the enzyme. Both molecules are bound in a similar fashion by a network of hydrogen bond interactions in a......Crystal structures of seryl-tRNA synthetase from Thermus thermophilus complexed with two different analogs of seryl adenylate have been determined at 2.5 Angstrom resolution. The first complex is between the enzyme and seryl-hydroxamate-AMP (adenosine monophosphate), produced enzymatically in the...

  17. Crystal structure of tRNA m(1)A58 methyltransferase TrmI from Aquifex aeolicus in complex with S-adenosyl-L-methionine.

    Science.gov (United States)

    Kuratani, Mitsuo; Yanagisawa, Tatsuo; Ishii, Ryohei; Matsuno, Michiyo; Si, Shu-Yi; Katsura, Kazushige; Ushikoshi-Nakayama, Ryoko; Shibata, Rie; Shirouzu, Mikako; Bessho, Yoshitaka; Yokoyama, Shigeyuki

    2014-09-01

    The N (1)-methyladenosine residue at position 58 of tRNA is found in the three domains of life, and contributes to the stability of the three-dimensional L-shaped tRNA structure. In thermophilic bacteria, this modification is important for thermal adaptation, and is catalyzed by the tRNA m(1)A58 methyltransferase TrmI, using S-adenosyl-L-methionine (AdoMet) as the methyl donor. We present the 2.2 Å crystal structure of TrmI from the extremely thermophilic bacterium Aquifex aeolicus, in complex with AdoMet. There are four molecules per asymmetric unit, and they form a tetramer. Based on a comparison of the AdoMet binding mode of A. aeolicus TrmI to those of the Thermus thermophilus and Pyrococcus abyssi TrmIs, we discuss their similarities and differences. Although the binding modes to the N6 amino group of the adenine moiety of AdoMet are similar, using the side chains of acidic residues as well as hydrogen bonds, the positions of the amino acid residues involved in binding are diverse among the TrmIs from A. aeolicus, T. thermophilus, and P. abyssi. PMID:24894648

  18. Structure of bacterial respiratory complex I.

    Science.gov (United States)

    Berrisford, John M; Baradaran, Rozbeh; Sazanov, Leonid A

    2016-07-01

    Complex I (NADH:ubiquinone oxidoreductase) plays a central role in cellular energy production, coupling electron transfer between NADH and quinone to proton translocation. It is the largest protein assembly of respiratory chains and one of the most elaborate redox membrane proteins known. Bacterial enzyme is about half the size of mitochondrial and thus provides its important "minimal" model. Dysfunction of mitochondrial complex I is implicated in many human neurodegenerative diseases. The L-shaped complex consists of a hydrophilic arm, where electron transfer occurs, and a membrane arm, where proton translocation takes place. We have solved the crystal structures of the hydrophilic domain of complex I from Thermus thermophilus, the membrane domain from Escherichia coli and recently of the intact, entire complex I from T. thermophilus (536 kDa, 16 subunits, 9 iron-sulphur clusters, 64 transmembrane helices). The 95Å long electron transfer pathway through the enzyme proceeds from the primary electron acceptor flavin mononucleotide through seven conserved Fe-S clusters to the unusual elongated quinone-binding site at the interface with the membrane domain. Four putative proton translocation channels are found in the membrane domain, all linked by the central flexible axis containing charged residues. The redox energy of electron transfer is coupled to proton translocation by the as yet undefined mechanism proposed to involve long-range conformational changes. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt. PMID:26807915

  19. Effect of adjuncts on microbiological and chemical properties of Scamorza cheese.

    Science.gov (United States)

    Guidone, Angela; Braghieri, Ada; Cioffi, Silvia; Claps, Salvatore; Genovese, Francesco; Morone, Giuseppe; Napolitano, Fabio; Parente, Eugenio

    2015-03-01

    Scamorza is a semi-hard, pasta filata cheese resembling low-moisture Mozzarella cheese, with a short ripening time (starter: Streptococcus thermophilus or S. thermophilus with peptidolytic Lactococcus lactis, Lactobacillus helveticus, and Lactobacillus paracasei strains as adjuncts). The cheeses were ripened for 30d. The adjunct did not significantly affect acid production or growth of the primary starter; 2 of the species used in the adjunct (Lb. paracasei and Lb. helveticus) rapidly colonized the cheese and persisted until the end of ripening, whereas the counts of nonstarter lactic acid bacteria in the control cheese were low until the end of ripening. The use of adjuncts affected pH, microbial composition (as assessed by both culture-dependent and culture-independent methods), total free amino acid content, and volatile profile (measured using an electronic nose), whereas milk type had only a minor effect. Although differences in primary proteolysis were found, they were probably indirect and related to the effects on pH and moisture. We conclude that, even with a short ripening time (30d), use of a peptidolytic adjunct may significantly affect important features of Scamorza and may be used to create a product that is measurably different from competing products. PMID:25582584

  20. EFFECTS OF ARTICHOKE (CYNARA SCOLYMUS L. EXTRACT ADDITION ON MICROBIOLOGICAL AND PHYSICO-CHEMICAL PROPERTIES OF PROBIOTIC YOGURT

    Directory of Open Access Journals (Sweden)

    Jalal Ehsani

    2015-06-01

    Full Text Available In this study, the effects of addition of artichoke (Cynara scolymus L. leaf extract into yogurt (0 or 0.5% on biochemical parameters (pH, titrable acidity and the viability of probiotic bacteria (Lactobacillus acidophilus LA-5, Bifidobacterium lactis BB-12 during fermentation and over 28 days of refrigerated storage (4°C were investigated. Moreover, the amounts of syneresis, total phenolic content, antioxidant activity and sensory attributes of yogurts at the end of fermentation were assessed. Yogurts contained the two yogurt bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus: ABY or only S. thermophilus (ABT as adjunct culture to probiotics. Yogurts containing Cynara scolymus L. (ABT-C and ABY-C had faster acidity increase, shorter incubation time and greater final titrable acidity than control yogurts (ABT and ABY. Also, yogurts containing Cynara scolymus L. had lower syneresis, higher total phenolic content and greater antioxidant activity. ABT-C yogurt had the ever greatest viability of probiotics. In case of samples sensory evaluation, generally, the highest total score was related to ABT yogurt whereas lowest total score belonged to ABT-C yogurt.

  1. Ribosome engineering to promote new crystal forms

    International Nuclear Information System (INIS)

    Truncation of ribosomal protein L9 in T. thermophilus allows the generation of new crystal forms and the crystallization of ribosome–GTPase complexes. Crystallographic studies of the ribosome have provided molecular details of protein synthesis. However, the crystallization of functional complexes of ribosomes with GTPase translation factors proved to be elusive for a decade after the first ribosome structures were determined. Analysis of the packing in different 70S ribosome crystal forms revealed that regardless of the species or space group, a contact between ribosomal protein L9 from the large subunit and 16S rRNA in the shoulder of a neighbouring small subunit in the crystal lattice competes with the binding of GTPase elongation factors to this region of 16S rRNA. To prevent the formation of this preferred crystal contact, a mutant strain of Thermus thermophilus, HB8-MRCMSAW1, in which the ribosomal protein L9 gene has been truncated was constructed by homologous recombination. Mutant 70S ribosomes were used to crystallize and solve the structure of the ribosome with EF-G, GDP and fusidic acid in a previously unobserved crystal form. Subsequent work has shown the usefulness of this strain for crystallization of the ribosome with other GTPase factors

  2. Nutritive characteristics of probiotic quark as influenced by type of starter

    Directory of Open Access Journals (Sweden)

    Đurić Mirjana S.

    2007-01-01

    Full Text Available Quark was manufactured, under laboratory conditions, by standard batch process, from two types of milk: I partially skimmed, with 1.6 % of fat and II whole milk, with 3.5 % of fat. As starters, two probiotic cultures were applied: I DVS-Probio-TecTM ABT- 1, Lactobacillus acidophilus-5, Bifidobacterium-12, S. thermophilus and II DVS-Probio-TecTM ABT-2, Lactobacillus acidophilus-5, Bifidobacterium-12, S. thermophilus. Also, the traditional cheese culture (CH - N22 was used. The obtained Quark samples were tested by standard methods in order to determine their nutritive characteristics. The results have shown that probiotic starter ABT-1 ensured the highest level of utilization of fat, proteins, lactose and phosphorus from partially skimmed milk. Probiotic culture ABT-2 was less effective, but combined with the traditional starter and applied to a whole milk could give Quark with acceptable nutritive characteristics. When sensory characteristics of products were tested, it has been proven that the application of ABT-2 culture and combination of probiotic starters ABT-2 and traditional culture gave good products with typical mild flavor. On the contrary, inoculation with ABT-1 probiotic starter resulted in lower-quality products in case of both kinds of milk applied. .

  3. Thermal adaptation of conformational dynamics in ribonuclease H.

    Directory of Open Access Journals (Sweden)

    Kate A Stafford

    Full Text Available The relationship between inherent internal conformational processes and enzymatic activity or thermodynamic stability of proteins has proven difficult to characterize. The study of homologous proteins with differing thermostabilities offers an especially useful approach for understanding the functional aspects of conformational dynamics. In particular, ribonuclease HI (RNase H, an 18 kD globular protein that hydrolyzes the RNA strand of RNA:DNA hybrid substrates, has been extensively studied by NMR spectroscopy to characterize the differences in dynamics between homologs from the mesophilic organism E. coli and the thermophilic organism T. thermophilus. Herein, molecular dynamics simulations are reported for five homologous RNase H proteins of varying thermostabilities and enzymatic activities from organisms of markedly different preferred growth temperatures. For the E. coli and T. thermophilus proteins, strong agreement is obtained between simulated and experimental values for NMR order parameters and for dynamically averaged chemical shifts, suggesting that these simulations can be a productive platform for predicting the effects of individual amino acid residues on dynamic behavior. Analyses of the simulations reveal that a single residue differentiates between two different and otherwise conserved dynamic processes in a region of the protein known to form part of the substrate-binding interface. Additional key residues within these two categories are identified through the temperature-dependence of these conformational processes.

  4. Combining crystallography and EPR: crystal and solution structures of the multidomain cochaperone DnaJ

    Energy Technology Data Exchange (ETDEWEB)

    Barends, Thomas R. M., E-mail: thomas.barends@mpimf-heidelberg.mpg.de [MPI for Medical Research, Heidelberg (Germany); Brosi, Richard W. W. [Freie Universitat Berlin, Berlin (Germany); Steinmetz, Andrea; Scherer, Anna; Hartmann, Elisabeth; Eschenbach, Jessica; Lorenz, Thorsten [MPI for Medical Research, Heidelberg (Germany); Seidel, Ralf [MPI for Molecular Physiology, Dortmund (Germany); Shoeman, Robert L.; Zimmermann, Sabine [MPI for Medical Research, Heidelberg (Germany); Bittl, Robert [Freie Universitat Berlin, Berlin (Germany); Schlichting, Ilme; Reinstein, Jochen [MPI for Medical Research, Heidelberg (Germany)

    2013-08-01

    The crystal structure of the N-terminal part of T. thermophilus DnaJ unexpectedly showed an ordered GF domain and guided the design of a construct enabling the first structure determination of a complete DnaJ cochaperone molecule. By combining the crystal structures with spin-labelling EPR and cross-linking in solution, a dynamic view of this flexible molecule was developed. Hsp70 chaperones assist in a large variety of protein-folding processes in the cell. Crucial for these activities is the regulation of Hsp70 by Hsp40 cochaperones. DnaJ, the bacterial homologue of Hsp40, stimulates ATP hydrolysis by DnaK (Hsp70) and thus mediates capture of substrate protein, but is also known to possess chaperone activity of its own. The first structure of a complete functional dimeric DnaJ was determined and the mobility of its individual domains in solution was investigated. Crystal structures of the complete molecular cochaperone DnaJ from Thermus thermophilus comprising the J, GF and C-terminal domains and of the J and GF domains alone showed an ordered GF domain interacting with the J domain. Structure-based EPR spin-labelling studies as well as cross-linking results showed the existence of multiple states of DnaJ in solution with different arrangements of the various domains, which has implications for the function of DnaJ.

  5. Role of milk protein-based products in some quality attributes of goat milk yogurt.

    Science.gov (United States)

    Gursel, A; Gursoy, A; Anli, E A K; Budak, S O; Aydemir, S; Durlu-Ozkaya, F

    2016-04-01

    Goat milk yogurts were manufactured with the fortification of 2% (wt/vol) skim goat milk powder (SGMP), sodium caseinate (NaCn), whey protein concentrate (WPC), whey protein isolate (WPI), or yogurt texture improver (YTI). Yogurts were characterized based on compositional, microbiological, and textural properties; volatile flavor components (with gas chromatography); and sensory analyses during storage (21d at 5°C). Compared with goat milk yogurt made by using SGMP, the other goat milk yogurt variants had higher protein content and lower acidity values. Goat milk yogurts with NaCn and WPC, in particular, had better physical characteristics. Using WPI caused the hardest structure in yogurt, leading to higher syneresis values. Acetaldehyde and ethanol formation increased with the incorporation of WPI, WPC, or YTI to yogurt milk. The tyrosine value especially was higher in the samples with NaCn and YTI than in the samples with WPC and WPI. Counts of Streptococcus thermophilus were higher than the counts of Lactobacillus delbrueckii ssp. bulgaricus, possibly due to a stimulatory effect of milk protein-based ingredients other than SGMP on the growth of S. thermophilus. Yogurt with NaCn was the best accepted among the yogurts. For the parameters used, milk protein-based products such as NaCn or WPC have promising features as suitable ingredients for goat milk yogurt manufacture. PMID:26874417

  6. Selection of dairy culture and changes of Podravec cheese acidity during production

    Directory of Open Access Journals (Sweden)

    Slavko Kirin

    2002-06-01

    Full Text Available The selection and characteristics of dairy culture play a basic role in all types of cheese production process. The most important characteristic is acidification ability i.e. lactic acid formation, which regulates manufacturing and maturing conditions of cheese, thus affecting its organoleptic characteristics as well. In this work the results on control of acidity increase in Podravec cheeseproduction are presented. In the production process, a technical culture as well as identical frozen and concentrated culture, with and without auxiliary Streptococcus thermophilus for direct milk inoculation, were used. It was established that the acidity, expressed as pH value, is more intensively developed in cheeses produced with culture for direct inoculation. This was especially evident in the first phases of production i.e. before cheese salting. During salting the acidity of cheeses, in both cases, was almoust identical. Cheeses produced with identical frozen culture and auxiliary Streptococcus thermophilus culture had more pronounced acidity before salting and lower after salting in comparison with cheeses with the mentioned two cultures. Organoleptic and other characteristics of mature cheeses were identical.

  7. Identifikace bakterií mléčného kvašení v kysaných mléčných výrobcích s využitím amplifikačních metod

    OpenAIRE

    Tycová, Martina

    2008-01-01

    Polymerázová řetěžová reakce (PCR) je molekulární diagnostická metoda, která umožňuje identifikaci bakterií mléčného kvašení používaných v potravinářském průmyslu. V této práci byla použita PCR pro identifikaci bakterií druhu Streptococcus thermophilus v 10-ti náhodně vybraných komerčně dostupných kysaných mléčných výrobcích a pro identifikaci druhu Streptococcus thermophilus v 25 lyofilizátech kmenů získaných ze Sbírky mlékařských kultur Laktoflóra (CCDM, Tábor, CZ). Druhově specifické PCR p...

  8. 益生菌Lactobacillus helveticus H9在脱脂乳中复配发酵特性研究%Mixed fermentation characteristic of probiotic Lactobacillus helveticus H9 in skim

    Institute of Scientific and Technical Information of China (English)

    陈永福; 李常坤; 王记成

    2015-01-01

    将益生菌Lactobacillus helveticus H9分别与Lactococcus lactis、Streptococcus thermophilus及Lactobacillus delbrueckii subsp.bulgaricus和Streptococcus thermophilus三类不同的菌种复配发酵脱脂乳,对其复配发酵乳的ACE抑制率、Val-Pro-Pro浓度、Ile-Pro-Pro浓度、游离氨基氮浓度、滴定酸度、pH值、活菌数、黏度、脱水收缩性和凝乳时间进行测定.结果表明,L.helveticus H9与Streptococcus thermophilus IMAU40115, Lactococcus lactis subsp.cremoris IMAU60065,Lactococcus lactis subsp.cremoris IMAU60064,L.delbrueckii subsp.bulgaricus IMAU20094和Streptococcus thermophilus IMAU40051的复配发酵乳的ACE抑制率大于60%,而且和IMAU40115、IMAU20094和IMAU40051的复配发酵乳具有较高的Val-Pro-Pro和Ile-Pro-Pro浓度.从复配菌种的种类分析发现,Lactococcus lactis较Streptococcus thermophilus和酸奶发酵剂更适宜与L.helveticus H9复配发酵.本文为进一步研究L helveticus H9发酵乳的开发提供了借鉴.

  9. Fermentation and storage of probiotic yoghurt from goat’s milk

    Directory of Open Access Journals (Sweden)

    Rajka Božanić

    2002-04-01

    Full Text Available Cow’s and goat’s milk supplemented with inulin were fermented withABT4 culture. The population growth of Streptococcus thermophilus,Lactobacillus acidophilus and Bifidobacterium ssp. in plain and inulinsupplemented goat’s milk during fermentation was evaluated. The survival of strains during 28 d of storage was followed in comparison with that of cow’s milk. The time required to reach the desired pH of 4.6 during fermentation was 6 h for both types of milk. At that time the proportion of viable cells of Streptococcus thermophilus, Lactobacillus acidophilus and Bifidobacterium ssp. in all fermented samples was comparable 40 : 33 : 27, respectively. During the storage viable count of streptococci and bifidobacteria have not decreased. In supplemented samples viable counts of bifidobacteria were increased and during 28th day of storage were higher for 0.6 logarithms compared to the non supplemented samples. Surviving of lactobacilli was poorer in fermented goat's milk than in fermented cow's milk during storage. The addition of inulin improved the firmness of fermented goat’s and cow’s milks products. Inulin addition partly masked the goat’s flavour of produced yoghurt. During storage the fermented goat's samples were scored better in comparison with cow's samples. Goat’s milk fermented with probiotic bacteria and fortified with inulin complies with the requirements of functional food.

  10. The regulatory mechanism underlying light-inducible production of carotenoids in nonphototrophic bacteria.

    Science.gov (United States)

    Takano, Hideaki

    2016-07-01

    Light is a ubiquitous environmental factor serving as an energy source and external stimulus. Here, I review the conserved molecular mechanism of light-inducible production of carotenoids in three nonphototrophic bacteria: Streptomyces coelicolor A3(2), Thermus thermophilus HB27, and Bacillus megaterium QM B1551. A MerR family transcriptional regulator, LitR, commonly plays a central role in their light-inducible carotenoid production. Genetic and biochemical studies on LitR proteins revealed a conserved function: LitR in complex with adenosyl B12 (AdoB12) has a light-sensitive DNA-binding activity and thus suppresses the expression of the Crt biosynthesis gene cluster. The in vitro DNA-binding and transcription assays showed that the LitR-AdoB12 complex serves as a repressor allowing transcription initiation by RNA polymerase in response to illumination. The existence of novel light-inducible genes and the unique role of the megaplasmid were revealed by the transcriptomic analysis of T. thermophilus. The findings suggest that LitR is a general regulator responsible for the light-inducible carotenoid production in the phylogenetically divergent nonphototrophic bacteria, and that LitR performs diverse physiological functions in bacteria. PMID:26967471

  11. Combining crystallography and EPR: crystal and solution structures of the multidomain cochaperone DnaJ

    International Nuclear Information System (INIS)

    The crystal structure of the N-terminal part of T. thermophilus DnaJ unexpectedly showed an ordered GF domain and guided the design of a construct enabling the first structure determination of a complete DnaJ cochaperone molecule. By combining the crystal structures with spin-labelling EPR and cross-linking in solution, a dynamic view of this flexible molecule was developed. Hsp70 chaperones assist in a large variety of protein-folding processes in the cell. Crucial for these activities is the regulation of Hsp70 by Hsp40 cochaperones. DnaJ, the bacterial homologue of Hsp40, stimulates ATP hydrolysis by DnaK (Hsp70) and thus mediates capture of substrate protein, but is also known to possess chaperone activity of its own. The first structure of a complete functional dimeric DnaJ was determined and the mobility of its individual domains in solution was investigated. Crystal structures of the complete molecular cochaperone DnaJ from Thermus thermophilus comprising the J, GF and C-terminal domains and of the J and GF domains alone showed an ordered GF domain interacting with the J domain. Structure-based EPR spin-labelling studies as well as cross-linking results showed the existence of multiple states of DnaJ in solution with different arrangements of the various domains, which has implications for the function of DnaJ

  12. Estudio microbiológico comparativo de yogur fresco y termizado en un modelo animal in vivo Comparative microbiological study of fresh and heat-treated yoghurt in an in vivo animal model

    Directory of Open Access Journals (Sweden)

    J. E. García de los Ríos

    2003-08-01

    Full Text Available En un ensayo agudo, ratas en ayunas de 24 h fueron sondadas con 2 ml de yogur fresco, yogur termizado o agua destilada, y se sacrificaron a las 2, 4, 8 y 24 h después, siendo comparadas con ratas sin sondar. Se determinó la supervivencia de las bacterias lácticas del yogur administrado en estómago e intestinos de los animales, y si las bacterias aisladas tenían el perfil de las cepas de Lactobacillus delbrueckii subsp. bulgaricus y Streptococcus thermophilus aisladas originalmente del yogur. Tambien se hizo el recuento del número de microorganismos totales que crecían en el medios para lactobacilos y estreptococos lácticos. Se hicieron análisis de los diferentes tipos de colonias resultantes en los medios para lactobacilos y estreptococos lácticos. Ninguna de las colonias caracterizadas en este ensayo agudo resultó ser L. delbrueckii subsp. bulgaricus o S. thermophilus. El análisis estadístico de los resultados no mostró diferencias significativas en el log UFC · g-1, de la microbiota intestinal de los cuatro grupos de animales en ninguno de los tiempos. En un ensayo crónico, se sacrificaron tres grupos de animales, alojados en células individuales de metabolismo, tras 30 días de alimentación ad libitum con dieta semisintética con 10% de yogur fresco, con 10% de yogur termizado o solo con dieta semisintética. Los resultados no mostraron diferencias significativas en el log UFC · g-1 de los microorganismos de la microbiota intestinal entre los tres grupos de animales en ninguno de los tiempos. A su vez, se caracterizaron los diferentes tipos de colonias resultantes en los medios para lactobacilos y estreptococos lácticos, y ninguna de las colonias caracterizadas en este ensayo crónico resultó ser L. delbrueckii subsp. bulgaricus o S. thermophilus.In an acute assay, rats fasted for 24 h were sounded with 2 ml of fresh yogurt, sterilised yogurt or distilled water, and sacrificed at 2, 4, 8 and 24 h. They were compared with

  13. Development of a multiplex real time PCR to detect thermophilic lactic acid bacteria in natural whey starters.

    Science.gov (United States)

    Bottari, Benedetta; Agrimonti, Caterina; Gatti, Monica; Neviani, Erasmo; Marmiroli, Nelson

    2013-01-01

    A multiplex real time PCR (mRealT-PCR) useful to rapidly screen microbial composition of thermophilic starter cultures for hard cooked cheeses and to compare samples with potentially different technological properties was developed. Novel primers directed toward pheS gene were designed and optimized for multiple detection of Lactobacillus helveticus, Lactobacillus delbrueckii, Streptococcus thermophilus and Lactobacillus fermentum. The assay was based on SYBR Green chemistry followed by melting curves analysis. The method was then evaluated for applications in the specific detection of the 4 lactic acid bacteria (LAB) in 29 different natural whey starters for Parmigiano Reggiano cheese production. The results obtained by mRealT-PCR were also compared with those obtained on the same samples by Fluorescence in Situ Hybridization (FISH) and Length-Heterogeneity PCR (LH-PCR). The mRealT-PCR developed in this study, was found to be effective for analyzing species present in the samples with an average sensitivity down to less than 600 copies of DNA and therefore sensitive enough to detect even minor LAB community members of thermophilic starter cultures. The assay was able to describe the microbial population of all the different natural whey starter samples analyzed, despite their natural variability. A higher number of whey starter samples with S. thermophilus and L. fermentum present in their microbial community were revealed, suggesting that these species could be more frequent in Parmigiano Reggiano natural whey starter samples than previously shown. The method was more effective than LH-PCR and FISH and, considering that these two techniques have to be used in combination to detect the less abundant species, the mRealT-PCR was also faster. Providing a single step sensitive detection of L. helveticus, L. delbrueckii, S. thermophilus and L. fermentum, the developed mRealT-PCR could be used for screening thermophilic starter cultures and to follow the presence of

  14. Recognition of tRNAs with a long variable arm by aminoacyl-tRNA synthetases

    Directory of Open Access Journals (Sweden)

    Tukalo M. A.

    2013-07-01

    Full Text Available In prokaryotic cells three tRNA species, tRNASer, tRNALeu and tRNATyr, possess a long variable arm of 11–20 nucleotides (type 2 tRNA rather than usual 4 or 5 nucleotides (type 1 tRNA. In this review we have summarized the results of our research on the structural basis for recognition and discrimination of type 2 tRNAs by Thermus thermophilus seryl-, tyrosyl- and leucyl-tRNA synthetases (SerRS, TyrRS and LeuRS obtained by X-ray crystallography and chemical probing tRNA in solution. Crystal structures are now known of all three aminoacyl-tRNA synthetases complexed with type 2 tRNAs and the different modes of tRNA recognition represented by these structures will be discussed. In particular, emphasis will be given to the results on recognition of characteristic shape of type 2 tRNAs by cognate synthetases. In tRNASer, tRNATyr and tRNALeu the orientation of the long variable arm with respect to the body of the tRNA is different and is controlled by different packing of the core. In the case of SerRS the N-terminal domain and in the case of TyrRS, the C-terminal domain, bind to the characteristic long variable arm of the cognate RNA, thus recognizing the unique shape of the tRNA. The core of T. thermophilus tRNALeu has several layers of unusual base-pairs, which are revealed by the crystal structure of tRNALeu complexed with T. thermophilus LeuRS and by probing a ligand-free tRNA by specific chemical reagents in solution. In the crystal structure of the LeuRS-tRNALeu complex the unique D-stem structure is recognized by the C-terminal domain of LeuRS and these data are in good agreement with those obtained in solution. LeuRS has canonical class I mode of tRNA recognition, approaching the tRNA acceptor stem from the D-stem and minor groove of the acceptor stem side. SerRS also has canonical class II mode of tRNA recognition and approaches tRNASer from opposite, variable stem and major groove of acceptor stem site. And finally, TyrRS in strong

  15. Probiotic viability and storage stability of yogurts and fermented milks prepared with several mixtures of lactic acid bacteria.

    Science.gov (United States)

    Mani-López, E; Palou, E; López-Malo, A

    2014-05-01

    Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35 d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥ 10(7)cfu/mL for 3 wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥ 10(7) cfu/mL for 35 d, of L. casei for 7d, and of L. reuteri for 14 d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This

  16. Effects of synbiotic fermented milk containing Lactobacillus acidophilus La-5 and Bifidobacterium animalis ssp. lactis BB-12 on the fecal microbiota of adults with irritable bowel syndrome: A randomized double-blind, placebo-controlled trial.

    Science.gov (United States)

    Bogovič Matijašić, Bojana; Obermajer, Tanja; Lipoglavšek, Luka; Sernel, Tjaša; Locatelli, Igor; Kos, Mitja; Šmid, Alenka; Rogelj, Irena

    2016-07-01

    We conducted a randomized double-blind, placebo-controlled multicentric study to investigate the influence of a synbiotic fermented milk on the fecal microbiota composition of 30 adults with irritable bowel syndrome (IBS). The synbiotic product contained Lactobacillus acidophilus La-5, Bifidobacterium animalis ssp. lactis BB-12, Streptococcus thermophilus, and dietary fiber (90% inulin, 10% oligofructose), and a heat-treated fermented milk without probiotic bacteria or dietary fiber served as placebo. Stool samples were collected after a run-in period, a 4-wk consumption period, and a 1-wk follow-up period, and were subjected to real-time PCR and 16S rDNA profiling by next-generation sequencing. After 4wk of synbiotic (11 subjects) or placebo (19 subjects) consumption, a greater increase in DNA specific for L. acidophilus La-5 and Bifidobacterium animalis ssp. lactis was detected in the feces of the synbiotic group compared with the placebo group by quantitative real-time PCR. After 1wk of follow-up, the content of L. acidophilus La-5 and B. animalis ssp. lactis decreased to levels close to initial levels. No significant changes with time or differences between the groups were observed for Lactobacillus, Enterobacteriaceae, Bifidobacterium, or all bacteria. The presence of viable BB-12- and La-5-like bacteria in the feces resulting from the intake of synbiotic product was confirmed by random amplification of polymorphic DNA (RAPD)-PCR. At the end of consumption period, the feces of all subjects assigned to the synbiotic group contained viable bacteria with a BB-12-like RAPD profile, and after 1wk of follow-up, BB-12-like bacteria remained in the feces of 87.5% of these subjects. The presence of La-5-like colonies was observed less frequently (37.5 and 25% of subjects, respectively). Next-generation sequencing of 16S rDNA amplicons revealed that only the percentage of sequences assigned to Strep. thermophilus was temporarily increased in both groups, whereas the

  17. Short communication: survival of the characteristic microbiota in probiotic fermented camel, cow, goat, and sheep milks during refrigerated storage.

    Science.gov (United States)

    Varga, L; Süle, J; Nagy, P

    2014-01-01

    The objective of this study was to monitor the viability during storage of Lactobacillus acidophilus LA-5 (A), Bifidobacterium animalis ssp. lactis BB-12 (B), and Streptococcus thermophilus CHCC 742/2130 (T) in probiotic cultured dairy foods made from pasteurized camel, cow, goat, and sheep milks fermented by an ABT-type culture. The products manufactured were stored at 4°C for 42d. Microbiological analyses were performed at weekly intervals. Streptococcus thermophilus CHCC 742/2130 was the most numerous culture component in all 4 products both at the beginning and at the end of storage. The viable counts of streptococci showed no significant decline in fermented camel milk throughout the entire storage period. The initial numbers of Lb. acidophilus LA-5 were over 2 orders of magnitude lower than those of Strep. thermophilus CHCC 742/2130. With the progress of time, a slow and constant decrease was observed in lactobacilli counts; however, the final viability percentages of this organism did not differ significantly in the probiotic fermented milks tested. The cultured dairy foods made from cow, sheep, and goat milks had comparable B. animalis ssp. lactis BB-12 counts on d 0, exceeding by approximately 0.5 log10 cycle those in the camel milk-based product. No significant losses occurred in viability of bifidobacteria in fermented camel, cow, and sheep milks during 6wk of refrigerated storage. In conclusion, all 4 varieties of milk proved to be suitable raw materials for the manufacture of ABT-type fermented dairy products that were microbiologically safe and beneficial for human consumption. It was suggested that milk from small ruminants be increasingly used to produce probiotic fermented dairy foods. The development of camel milk-based probiotic cultured milks appears to be even more promising because new markets could thus be conquered. It must be emphasized, however, that further microbiological and sensory studies, technology development activities, and

  18. Crystal structure of ribosomal protein L1 from the bacterium Aquifex aeolicus

    Science.gov (United States)

    Nikonova, E. Yu.; Tishchenko, S. V.; Gabdulkhakov, A. G.; Shklyaeva, A. A.; Garber, M. B.; Nikonov, S. V.; Nevskaya, N. A.

    2011-07-01

    The crystal structure of ribosomal protein L1 from the bacterium Aquifex aeolicus was solved by the molecular-replacement method and refined to R cryst = 19.4% and R free = 25.1% at 2.1 Å protein consists of two domains linked together by a flexible hinge region. In the structure under consideration, the domains are in close proximity and adopt a closed conformation. Earlier, this conformation has been found in the structure of protein L1 from the bacterium Thermus thermophilus, whereas the structures of archaeal L1 proteins and the structures of all L1 proteins in the RNA-bound form have an open conformation. The fact that a closed conformation was found in the structures of two L1 proteins which crystallize in different space groups and belong to different bacteria suggests that this conformation is a characteristic feature of L1 bacterial proteins in the free form.

  19. Analysis of aflatoxin M1 in milk and yogurt and AFM1 reduction by lactic acid bacteria used in Lebanese industry

    International Nuclear Information System (INIS)

    In this study a screening survey was undertaken to determine the presence and levels of aflatoxin M1 (AFM1) in locally produced dairy products. For this purpose, a total of 138 dairy samples (milk and yogurt) were analyzed to quantify AFM1 levels in these products. Results obtained showed that AFM1 was found in 40.62% and 32.81% of milk and yogurt samples respectively. The range of contamination levels varied between lower and higher than European regulation limit. Lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) used in the Lebanese traditional industry were screened for their ability to reduce the level of AFM1. Due to the lack in data on the natural occurrence of AFM1 in Lebanese dairy products, the aim of this work was to report some information and to state these products according to EC regulations. (author)

  20. Current taxonomy of phages infecting lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Jennifer eMahony

    2014-01-01

    Full Text Available Phages infecting lactic acid bacteria have been the focus of significant research attention over the past three decades. Through the isolation and characterization of hundreds of phage isolates, it has been possible to classify phages of the dairy starter and adjunct bacteria Lactococus lactis, Streptococcus thermophilus, Leuconostoc spp. and Lactobacillus spp. Among these, phages of L. lactis have been most thoroughly scrutinized and serve as an excellent model system to address issues that arise when attempting taxonomic classification of phages infecting other LAB species. Here, we present an overview of the current taxonomy of phages infecting LAB genera of industrial significance, the methods employed in these taxonomic efforts and how these may be employed for the taxonomy of phages of currently underrepresented and emerging phage species.

  1. Dicty_cDB: Contig-U11837-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available cName: Full=Sodium/potassium-transporting ATPase subu... 45 0.008 CP000609_857( CP000609 |pid:none) Methanococ...50 CP000023_1469( CP000023 |pid:none) Streptococcus thermophilus LMG ... 43 0.050 CP000300_395( CP000300 |pid:none) Methanococ... 50 2e-04 CP000423_681( CP000423 |pid:none) Lactobacillus casei ATCC 334, co... 50 2e-04 CP001393_1456( CP001393 |pid:none) Anaeroc...ne) Oncorhynchus mykiss Na/K ATPase al... 49 7e-04 CP000678_895( CP000678 |pid:none) Methanobrevibact...ATCC 8482,... 46 0.005 EU391598_1( EU391598 |pid:none) Myoxocephalus octodecemspinosus so... 46 0.005 BA0000

  2. Dicty_cDB: Contig-U16217-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available .. 38 0.78 3 ( BX119979 ) Zebrafish DNA sequence from clone CH211-201G8 in ... 44 0.81 7 ( EV866087 ) rpbfe0...T677259 ) Danio rerio EST, clone ZF_mu_162m07 5'. 48 1.1 2 ( EV868478 ) rpbfe0111... sequence. 38 1.6 2 ( CO953317 ) UMC-pfeto1-017-f08 Fetal ovary pfeto Sus scrofa c... 38 1.6 2 ( EV870684 ) rpbf... 1 ( AF316886 ) Streptococcus thermophilus oligopeptide binding p... 48 1.7 1 ( EV867579 ) rpbfe0102_d3.y1 b...fe Sus scrofa cDNA 5', mRNA sequ... 38 1.8 2 ( EV873666 ) rpbfe0136_c13.y1 bfe Sus scrofa cDNA 5', mRNA seq.

  3. Dicty_cDB: Contig-U10041-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Hond... 45 0.007 ( P14873 ) RecName: Full=Microtubule-associated protein 1B; ... 45 0....ranaerobius thermophilus JW/... 40 0.16 A56577( A56577 ) microtubule-associated protein MAP 1B - rat...e p... 45 0.005 ( O61308 ) RecName: Full=227 kDa spindle- and centromere-associate... 45 0.005 BC144019_1( BC144019 |pid:none...ecName: Full=STE20-like serine/threonine-protein kinas... 42 0.042 AY454096_1( AY454096 |pid:none) Plasmodium vivax isolate...modium reichenowi reticulocyte... 41 0.094 JC6009( JC6009 ) surface-located membrane protein lmp3 precurso

  4. AcEST: DK953428 [AcEST

    Lifescience Database Archive (English)

    Full Text Available plantlets Developmental stage gametophytes with sporophytes C...bonuclease Z OS=Streptococcus thermophilus... 31 4.1 >sp|Q9GL72|RNZ2_PANTR Zinc phosphodiesterase ELAC protein 2 OS=Pan troglodytes...us-veneris mRNA. clone: TST39A01NGRL0017_L22. 5' end sequence. Accession DK953428 Tissue type prothallia with...: Swiss-Prot sp_hit_id Q9GL72 Definition sp|Q9GL72|RNZ2_PANTR Zinc phosphodiesterase ELAC protein 2 OS=Pan troglodytes Align length...S1 Ribonuclease Z OS=Staphylococcus saprophytic... 37 0.057 sp|Q8NWE6|RNZ_STAAW Ribonuclease Z OS=Staphyloco

  5. Functional Starters for Functional Yogurt

    Directory of Open Access Journals (Sweden)

    Mattia P. Arena

    2015-02-01

    Full Text Available In this study, we investigated the multifunctionality (microbial starters and probiotics of Lactobacillus plantarum WCFS1 and Lactobacillus plantarum CECT 8328 strains used as microbial starters for the production of yogurt in combination with Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. The ability of the probiotic strains to survive oro-gastrointestinal stresses was monitored by an in vitro assay simulating the human digestive tract. The transcriptional level of several genes involved in the immune response suggested that the probiotic strains may have a favorable influence on immunomodulation. Overall, this study revealed that the tested Lactobacilli exhibited suitable technological features for yogurt production and might be used to formulate novel food with immunomodulating effects.

  6. Evaluation the Sensory and Probiotics Properties of the Yogurt Supplemented with Carrot Juice

    Directory of Open Access Journals (Sweden)

    Carmen R. Pop

    2015-11-01

    Full Text Available This study aimed to develop a new type of yogurt through addition of carrot juice. Yogurt is a fermented milk product obtained from fermentation of Lactobacillus bulgaricus and Streptococcus thermophilus strains. The effect of carrot juice at different levels (0%, 8%, 16%, 24% on sensory properties and the viability of probiotic bacteria in yogurts during storage (21 days at refrigerated temperature (4°C was evaluated. The yogurt supplementation with 24 % carrot juice significantly improves the stability of the lactic acid bacteria, that contained the recommended levels of 107 cfu/g probiotic bacteria at the end of 21-days shelf life. The yogurt with 24% carrot juice was the most appreciated (7.07 points, followed by the classic yogurt (6 points, yogurt with 8% (5.28 points and yogurt with16% carrot juice (5.5 points.

  7. Dicty_cDB: Contig-U12101-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 42_2( AY730642 |pid:none) Streptococcus thermophilus LMG 183... 39 0.67 T17699( T17699 ) arginine-rich protein a209R - Chlorel...727( CP000113 |pid:none) Myxococcus xanthus DK 1622, com... 38 1.1 BC141284_1( BC141284 |pid:none) Mus musculus pleiomorp...) Database: CSM 6905 sequences; 5,674,871 total letters Score E Sequences producing significant alignments: ... (Contig-U12101-1Q) /CSM_Contig/Contig-U12101-1Q.Seq.d Length = 1915 Score = 3164 bits (1596), Expect = 0.0 ..._Contig/Contig-U13446-1Q.Seq.d Length = 295 Score = 50.1 bits (25), Expect = 9e-06 Identities = 46/53 (86%)

  8. Ab initio single and multideterminant methods used in the determination of reduction potentials and magnetic properties of Rieske ferredoxins

    Science.gov (United States)

    Powers, Nathan Lee

    2008-10-01

    The [Fe2S2]2+/[Fe2S 2]+ electronic structure of seven Rieske protein active sites (bovine mitochondrial cytochrome bc1 complex, spinach chloroplast cytochrome b6f complex, Rieske-type ferredoxin associated with biphenyl dioxygenase from Burkholderia cepacia, yeast cytochrome bcl complex from Saccharomyces cerevisiae, Rieske subunit of arsenite oxidase from Alcaligenes faecalis, respiratory-type Rieske protein from Thermus thermophilus, and Rieske protein II (soxF) from Sulfolobus acidocaldarius), which lie in a reduction potential range from -150 mV to 375 mV, have been studied by both single and multi-determinant quantum mechanical methods. Calculated reduction potentials and magnetic properties are found comparable to experimental values.

  9. Dicty_cDB: Contig-U13879-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ( AJ716155 |pid:none) Trypanosoma brucei ACS 5 gene for ... 283 1e-74 CU928170_573( CU928170 |pid:none) Kluyveromyces thermotoler...some 1. 252 4e-65 CU928169_590( CU928169 |pid:none) Kluyveromyces thermotoler... CP000283_1566( CP000283 |pid:none) Rhodopseudomonas palustris BisB... 189 5e-46 AP008226_448( AP008226 |pid:none) Thermus thermo...21_79( AE017221 |pid:none) Thermus thermophilus HB27, comple... 183 3e-44 AM408590_2207( AM408590 |pid:none) Mycobacter..... 283 2e-74 FJ588017_1( FJ588017 |pid:none) Babesia bovis isolate Southeast ac... 280 2e-73 FJ588014_1( FJ5

  10. Serial femtosecond X-ray diffraction of 30S ribosomal subunit microcrystals in liquid suspension at ambient temperature using an X-ray free-electron laser

    International Nuclear Information System (INIS)

    Serial femtosecond X-ray (SFX) diffraction extending beyond 6 Å resolution using T. thermophilus 30S ribosomal subunit crystals is reported. High-resolution ribosome structures determined by X-ray crystallography have provided important insights into the mechanism of translation. Such studies have thus far relied on large ribosome crystals kept at cryogenic temperatures to reduce radiation damage. Here, the application of serial femtosecond X-ray crystallography (SFX) using an X-ray free-electron laser (XFEL) to obtain diffraction data from ribosome microcrystals in liquid suspension at ambient temperature is described. 30S ribosomal subunit microcrystals diffracted to beyond 6 Å resolution, demonstrating the feasibility of using SFX for ribosome structural studies. The ability to collect diffraction data at near-physiological temperatures promises to provide fundamental insights into the structural dynamics of the ribosome and its functional complexes

  11. Study on the removal of fish odour and bitter from protein hydrolysates of tilapia by-products by microorganism fermentation%微生物发酵对罗非鱼下脚料蛋白酶解液脱腥去苦效果比较

    Institute of Scientific and Technical Information of China (English)

    曾少葵; 杨萍; 陈秀红

    2009-01-01

    以嗜热链球菌(Streptococus thermophilus)、保加利亚乳杆菌(Lactobacillus bulgaricus)和瑞士乳杆菌(L.helveticus)及2种酿酒酵母菌(Saccharomyces cerevisiae)为菌种,对罗非鱼(Oreochromis niloticus)下脚料蛋白酶解液进行发酵,利用感官评定法,比较不同微生物发酵对酶解液脱腥去苦效果.试验结果表明,乳酸菌脱腥效果优于酵母菌,其中以嗜热链球菌脱腥效果最好,其适宜的发酵条件为接种量10%,发酵温度42℃,发酵时间9 h.微生物发酵去苦效果不明显.

  12. Production optimization of probiotic soft cheese made from goat's and cow's milk

    Directory of Open Access Journals (Sweden)

    Ida Drgalić

    2006-07-01

    Full Text Available The aim of this study was to determine optimal rennet share and fat content in milk for probiotic soft cheeseproduction made from goat's and cow's milk using DVS mixed probiotic culture ABT-4 (Lactobacillus acidophilus, Bifidobacterium spp. and Streptococcus thermophilus, with desirable sensory properties, which will be acceptable by consumers. The best sensory scores had samples of probiotic soft cheese produced in laboratory conditions from milk with 1% of milk fat, pasteurized at 65°C/30 min., fermented at 38°C with 2% culture. To achieve characteristic consistency of traditional soft cheese, 0.01% of rennet was added to goat's milk. Probiotic soft cheese made from cow's and goat's milk, produced under optimal conditions, were 100% acceptable by the tested consumers.

  13. Mozzarella干酪生产用菌种的筛选%Selection of Mozzarella cheese strains

    Institute of Scientific and Technical Information of China (English)

    刘会平; 南庆贤; 马长伟

    2003-01-01

    概述了Mozzarella干酪的特点以及生产用菌株所需具备的特性,从现有的菌种和市售优质酸乳中分离纯化得到25株乳酸菌,经初步的生产性能试验,筛选出12株性能较好的菌株.经进一步的发酵性能和生化试验,优选出两株优良的菌株,并初步鉴定为唾液链球菌嗜热亚种(Streptococcus salivarius subsp.Thermophilus)CH9和保加利亚乳杆菌德氏亚种(Lactobacillus delbrueckil ssp.Bulgaricus)LB,经过实际的干酪生产,证明表现良好.

  14. Effects of fermentation with Lactobacillus rhamnosus GG on product quality and fatty acids of goat milk yogurt.

    Science.gov (United States)

    Jia, Ru; Chen, Han; Chen, Hui; Ding, Wu

    2016-01-01

    The effect of fermentation with Lactobacillus rhamnosus GG on the product quality of goat milk yogurt using traditional yogurt starter was studied through single-factor experiments and orthogonal experiments. The optimum fermentation condition was evaluated by the titratable acidity of goat milk yogurt, water-retaining capability, sensory score, and texture properties; the fatty acids of the fermented goat milk were determined by a gas chromatograph. Results indicate that high product quality of goat milk yogurt can be obtained and the content of short-chain and medium-chain fatty acids can be decreased significantly when amount of sugar added was 7%, inoculation amount was 3%, the ratio of 3 lactic acid bacteria--Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus, and L. rhamnosus GG--was 1:1:3, and fermentation temperature was 42°C. PMID:26601583

  15. Microbiological characterization and functionality of set-type yogurt fermented with potential prebiotic substrates Cudrania tricuspidata and Morus alba L. leaf extracts.

    Science.gov (United States)

    Oh, Nam Su; Lee, Ji Young; Joung, Jae Yeon; Kim, Kyung Su; Shin, Yong Kook; Lee, Kwang-Won; Kim, Sae Hun; Oh, Sangnam; Kim, Younghoon

    2016-08-01

    The objective of this study was to investigate the effect of 2 plant leaf extracts on fermentation mechanisms and health-promoting activities and their potential as a nutraceutical prebiotics ingredient for application in dairy products. The individual active phenolic compounds in the plant extract-supplemented milk and yogurts were also identified. Compared with control fermentation, the plant extracts significantly increased the growth and acidification rate of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. In particular, plant extract components, including monosaccharides, formic acid, and hydroxycinnamic acid, such as neo-chlorogenic, chlorogenic, and caffeic acid, together play a stimulatory role and cause this beneficial effect on the growth of yogurt culture bacteria through fermentation. In addition, supplementation with the plant extracts enhanced antioxidant activities with increased total phenolic contents, especially the highest antioxidant activity was observed in yogurt supplemented with Cudrania tricuspidata leaf extract. PMID:27236762

  16. Yeast surface display of dehydrogenases in microbial fuel-cells.

    Science.gov (United States)

    Gal, Idan; Schlesinger, Orr; Amir, Liron; Alfonta, Lital

    2016-12-01

    Two dehydrogenases, cellobiose dehydrogenase from Corynascus thermophilus and pyranose dehydrogenase from Agaricus meleagris, were displayed for the first time on the surface of Saccharomyces cerevisiae using the yeast surface display system. Surface displayed dehydrogenases were used in a microbial fuel cell and generated high power outputs. Surface displayed cellobiose dehydrogenase has demonstrated a midpoint potential of -28mV (vs. Ag/AgCl) at pH=6.5 and was used in a mediator-less anode compartment of a microbial fuel cell producing a power output of 3.3μWcm(-2) using lactose as fuel. Surface-displayed pyranose dehydrogenase was used in a microbial fuel cell and generated high power outputs using different substrates, the highest power output that was achieved was 3.9μWcm(-2) using d-xylose. These results demonstrate that surface displayed cellobiose dehydrogenase and pyranose dehydrogenase may successfully be used in microbial bioelectrochemical systems. PMID:27459246

  17. Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci.

    Science.gov (United States)

    Peralta, Guillermo Hugo; Bergamini, Carina Viviana; Hynes, Erica Rut

    2016-01-01

    Aminotransferases and glutamate dehydrogenase are two main types of enzymes involved in the initial steps of amino acid catabolism, which plays a key role in the cheese flavor development. In the present work, glutamate dehydrogenase and aminotransferase activities were screened in twenty one strains of lactic acid bacteria of dairy interest, either cheese-isolated or commercial starters, including fifteen mesophilic lactobacilli, four thermophilic lactobacilli, and two streptococci. The strains of Streptococcus thermophilus showed the highest glutamate dehydrogenase activity, which was significantly elevated compared with the lactobacilli. Aspartate aminotransferase prevailed in most strains tested, while the levels and specificity of other aminotransferases were highly strain- and species-dependent. The knowledge of enzymatic profiles of these starter and cheese-isolated cultures is helpful in proposing appropriate combinations of strains for improved or increased cheese flavor. PMID:27266631

  18. Dicty_cDB: Contig-U15019-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 45 0.007 FN392319_1310( FN392319 |pid:none) Pichia pastoris GS115 chromosom... 45...-41 (Q48CD3) RecName: Full=Imidazolonepropionase; EC=3.5.2.... 171 9e-41 CU928164_686( CU928164 |pid:none) Escherichia coli IAI39 ch...lus strain RD678 urease op... 46 5.1 1 ( AJ544512 ) Streptococcus thermophilus partial urease operon,......8( CP000075 |pid:none) Pseudomonas syringae pv. syring... 49 7e-04 (B5YLB7) RecName: Full=5-methylthioadenosine/S-adenosylhomoc...... 41 0.18 (Q8U0P7) RecName: Full=5-methylthioadenosine/S-adenosylhomocyste... 41 0.18 CP000749_4054( CP000749 |pid:none) Marinomo

  19. 不同乳酸菌对羊酸奶的感官和质构特性的影响%The Effect of Different Lactobacillus on the Sensory and Textural Properties of Goat Yoghurt

    Institute of Scientific and Technical Information of China (English)

    祝静; 丁武

    2011-01-01

    研究分析不同乳酸菌对羊酸奶感官与质构特性的影响作用,为筛选优良的羊酸奶发酵剂提供依据.使用双歧杆菌、保加利亚乳杆菌、嗜热链球菌、丁二酮乳链球菌发酵羊奶,对羊酸奶的感官品质、酸度及质构特性进行评定.结果表明,单一菌种发酵,四种菌发酵的羊酸奶的感官评分排序是双歧杆菌>嗜热链球菌>保加利亚乳杆菌>丁二酮乳链球菌,不同乳酸菌发酵羊酸奶的质构特性差异显著,使用双歧杆菌发酵可以获得最佳的质构特性,其发酵的羊酸奶的硬度为34.96g、黏度为802.28g·s、凝聚性为44.65g、粘性指数为137.17g·s、保水力为85.00%;混合发酵剂发酵羊酸奶具有各自不同的感官和质构特性优势,双歧杆菌和嗜热链球菌发酵的羊酸奶的硬度和黏度最好,分别达到29.93g和715.09g·s,但风味欠佳;双歧杆菌和丁二酮乳链球菌发酵的羊酸奶的凝聚性、粘性指数和保水力最好,分别达到45.86g、143.49g·s、91.00%,且风味良好.综合感官评价与质构特性,复合菌种双歧杆菌和丁二酮乳链球菌适宜作为羊酸奶的发酵剂.%The effect of different lactobacillus on the sensory and textural properties of goat yoghurt was investigated, and a basis for selectiving better starters of goat yoghurt was provided. Goat milk was fermented by Bifidobacterium, Streptococcus thermophilus,Lactobacillus bulgaricus and Streptococcus diacetilucs, and their sensory evaluation, acidity and texture were determind. The result showed that fermentation by singlelactobocillus, the sensory order of the four kind oflactobocillus was Bifidobacterium>Streptococcus thermophilus >Lactobocillus bulgaricus >Streptococcus diacetilucs. Different lactobacillus was significantly different on textural properties, and the firmness, consistency, cohesiveness, index of viscosity and water holding capacity of goat yogurt fermented by Bifidobactedum were the best, the were 34

  20. The Incidence of Necrotizing Enterocolitis Is Increased Following Probiotic Administration to Preterm Pigs

    DEFF Research Database (Denmark)

    Cilieborg, Malene Skovsted; Thymann, Thomas; Boye, Mette;

    2011-01-01

    Preterm birth and necrotizing enterocolitis (NEC) is associated with inappropriate gut colonization and immunity, which may be improved by probiotic bacteria. Using a preterm pig model of NEC, we investigated the effects of probiotics on intestinal structure, function, microbiology, and immunology...... in the immediate postnatal period. Just after birth, caesarean-delivered preterm pigs were inoculated with Lactobacillus paracasei, Bifidobacteria animalis, and Streptococcus thermophilus (total 2.4 × 1010/d) either as live (ProLive, n = 14) or gamma-irradiated dead bacteria (ProDead, n = 12) and...... live probiotics induced a higher density of B. animalis and lower bacterial diversity in the distal intestinal mucosa and lower SCFA concentrations in the colon (P < 0.05). The detrimental effects of probiotic bacteria in this study may relate to the specific strain and dose combination and may have...

  1. STUDY OF GUSTATORY AND STRUCTURAL PROPERTIES OF KEFIR PRODUCT

    Directory of Open Access Journals (Sweden)

    MILENA H. MOMCHILOVA

    2012-06-01

    Full Text Available The subject of the study is the improvement of Kefir culture. For this investigation it was used Kefir culture and two series of experiments were carried out. Yeasts from probiotic strain Saccharomyces boulardii were added in the first series and the lactic acid bacteria (LAB of Streptococcus thermophilus strain, with a polysaccharide activity were added to Kefir culture in the second series. The fermentation conditions were 30°C, duration 16 hours and cooling 4 hours up to 4°C. The characteristics of Kefir were analyzed by determination of: pH, acidity, qualitative reaction for existence of diacetyl, cell number of LAB and yeasts. The structural properties of Kefir were evaluated by microscopic study.

  2. Dicty_cDB: Contig-U06527-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AM406671_1611( AM406671 |pid:none) Lactococcus lactis subsp. cremo... 149 4e-35 ( P52017 ) RecName: Full=Peptidyl-prolyl cis-tran...03( CP000023 |pid:none) Streptococcus thermophilus LMG 1... 135 6e-31 (Q9P3X9) RecName: Full=41 kDa peptidyl-prolyl cis-trans is.... 146 3e-34 CP000425_878( CP000425 |pid:none) Lactococcus lactis subsp. cremor... 146 3e-34 AE014186_151( AE014186 |pid:none) Plasmo...64( AM920689 |pid:none) Xanthomonas campestris pv. camp... 138 5e-32 CP000414_1626( CP000414 |pid:none) Leuconostoc...9( AY596297 |pid:none) Haloarcula marismortui ATCC 430... 128 7e-29 U36797_1( U36797 |pid:none) Hirudo medicinalis

  3. Bazı Antibiyotiklerin Yoğurt Bakterilerinin Asit Geliştirme Özellikleri Üzerine Etkileri

    OpenAIRE

    Temiz, Ayhan

    1985-01-01

    Bazı antibiyotiklerin (penisilin, streptomisin, oksitetrasiklin, tetrasiklin ve klortetrasiklin) yoğurt bakterilerinin sütteki asit geliştirme özellikleri üzerine etkileri incelenmiştir. Streptococcus thermophilus ve Lactobacillus bulgaricus kültürü ile bunların karışımıyla elde edilen yoğurt kültürünün, denenen antibiyotik konsantrasyonlarında gerçekleştirdikleri asit gelişimleri titre edilebilir asitlik ve pH olarak saptanmıştır. Asit gelişimleri, örneklerin 44 oC de 0, 2 ve 3 saat inkübasy...

  4. MICROBIOLOGICAL EVALUATION OF SOY FORTIFIED SHRIKHAND BY USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Dinker Singh

    2014-02-01

    Full Text Available Soy fortified shrikhand samples were prepared with various levels of soymilk, cane sugar and yoghurt culture (Lactobacillusdelbrueckii subsp. bulgaricusand Streptococcus thermophilusin the ratio of 1:1 examined for selective enumeration of health beneficial microorganisms. The present investigation was carried out to optimize the process for manufacturing of soy fortified shrikhand by its response with employing the 3-factor Central Composite Rotatable Design (CCRD. The formulated soy fortified shrikhand with 45.0% soymilk, 30.0% cane sugar and 3.0% yoghurt culture was found highly suitable (P<0.05 for obtaining the maximum viable count of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus whereas the desirability index was 0.985.

  5. Basal DNA repair machinery is subject to positive selection in ionizing-radiation-resistant bacteria

    International Nuclear Information System (INIS)

    In this work, we used the programs MultiParanoid and DnaSP to deduce the sets of orthologs that potentially evolved due to positive Darwinian selection in ionizing-radiation-resistant bacteria (IRRB ; Deinococcus geothermalis, Deinococcus radiodurans, Kineococcus radiotolerans, and Rubrobacter xylanophilus). We find that positive selection targets 689 ortholog sets of IRRB. Among these, 58 ortholog sets are absent in ionizing-radiation-sensitive bacteria (IRSB: Escherichia coli and Thermus thermophilus). The most striking finding is that all basal DNA repair genes in IRRB, unlike many of their orthologs in IRSB, are subject to positive selection. Our results provide the first in silico prediction of positively selected genes with potential roles in the molecular basis of resistance to gamma radiation and tolerance of desiccation in IRRB. Identification of these genes provides a basis for future experimental work aimed at understanding the metabolic networks in which they participate

  6. Improved immobilization of laccase on a glassy carbon electrode by oriented covalent attachment

    Directory of Open Access Journals (Sweden)

    Liu Xin

    2014-01-01

    Full Text Available A laccase from Thermus thermophilus HB27 was reported to be potentially useful in the design of a temperature controlled biofuel cell. For enhancing its application in different thermal conditions, we engineered a laccase-oriented immobilized electrode. A site-directed mutant N323C of the laccase was constructed. A photometric assay was employed in order to compare the catalytic properties of wild-type laccase and mutant. The mutant was attached to a glass carbon electrode by covalent cross-linking. The electrochemical properties of the immobilized laccase were investigated by cyclic voltammetry. This immobilization allowed the active electrode to function at temperatures up to 95°C. The thermal and pH dependence profiles were similar to those of the soluble enzyme investigated by spectrophotometry.

  7. Food environments select microorganisms based on selfish energetic behavior

    Directory of Open Access Journals (Sweden)

    DiegoMora

    2013-11-01

    Full Text Available Nutrient richness, and specifically the abundance of mono- and disaccharides that characterize several food matrixes, such as milk and grape juice, has allowed the speciation of lactic acid bacteria and yeasts with a high fermentation capacity instead of energetically favorable respiratory metabolism. In these environmental contexts, rapid sugar consumption and lactic acid or ethanol production, accumulation and tolerance, together with the ability to propagate in the absence of oxygen, are several of the ‘winning’ traits that have apparently evolved and become specialized to perfection in these fermenting microorganisms. Here, we summarize and discuss the evolutionary context that has driven energetic metabolism in food-associated microorganisms, using the dairy species Lactococcus lactis and Streptococcus thermophilus among prokaryotes and the bakers’ yeast Saccharomyces cerevisiae among eukaryotes as model organisms.

  8. Examining the possibilities of applying high pressure to preserve yoghurt supplemented with probiotic bacteria

    Science.gov (United States)

    Jankowska, Agnieszka; Grześkiewicz, Aleksandra; Wiśniewska, Krystyna; Reps, Arnold

    2012-09-01

    Natural yoghurt was subject to pressures of 200 and 250 MPa/4 and 18°C/15 min, after which milk-activated inocula of Lactobacillus acidophilus and Bifidobacterium sp. were added. The yoghurts were stored for 4 weeks at refrigeration temperature. After preparation and each week of storage, the count of bacteria, acidity, antibacterial property and an organoleptic assessment was determined. The highest survival rate was demonstrated by the bacteria of Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus thermophilus and Bifidobacterium sp. in the yoghurt pressurised 200 MPa/15min at 4°C. Acidity increases in the control yoghurts were higher than in the pressurised ones. Pressurised yoghurts demonstrated weaker antibacterial effect in comparison to control yoghurts. Slight changes in the smell and taste were observed after pressurisation. Yoghurts pressurised at 18°C were characterised by more favourable organoleptic properties. Better conciseness of the curd and lower whey seep out were observed in pressurised yoghurt.

  9. Bathymodiolus growth dynamics in relation to environmental fluctuations in vent habitats

    Science.gov (United States)

    Nedoncelle, K.; Lartaud, F.; Contreira Pereira, L.; Yücel, M.; Thurnherr, A. M.; Mullineaux, L.; Le Bris, N.

    2015-12-01

    The deep-sea mussel Bathymodiolus thermophilus is a dominant species in the East Pacific Rise (EPR) hydrothermal vent fields. On the EPR volcanically unstable area, this late colonizer reaches high biomass within 4-5 years on new habitats created by lava flows. The environmental conditions and growth rates characterizing the reestablishment of B. thermophilus populations are however largely unknown, leaving unconstrained the role of this foundation species in the ecosystem dynamics. A typical example from the vent field at 9°50'N that was affected by the last massive eruption was the Bio-9 hydrothermal vent site. Here, six years later, a large mussel population had reestablished. The von Bertalanffy growth model estimates the oldest B. thermophilus specimens to be 1.3 year-old in March 2012, consistent with the observation of scarce juveniles among tubeworms in 2010. Younger cohorts were also observed in 2012 but the low number of individuals, relatively to older cohorts, suggests limited survival or growth of new recruits at this site, that could reflect unsuitable habitat conditions. To further explore this asumption, we investigated the relationships between mussel growth dynamics and habitat properties. The approach combined sclerochronology analyses of daily shell growth with continuous habitat monitoring for two mussel assemblages; one from the Bio-9 new settlement and a second from the V-vent site unreached by the lava flow. At both vent sites, semi-diurnal fluctuations of abiotic conditions were recorded using sensors deployed in the mussel bed over 5 to 10 days. These data depict steep transitions from well oxygenated to oxygen-depleted conditions and from alkaline to acidic pH, combined with intermittent sulfide exposure. These semi-diurnal fluctuations exhibited marked changes in amplitude over time, exposing mussels to distinct regimes of abiotic constraints. The V-vent samples allowed growth patterns to be examined at the scale of individual life and

  10. Isolation and Identification of Lactic Acid Bacteria from Nature Fermented Dough%自然发酵面团中乳酸菌菌株的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    We obtained two lactic acid bacteria strains from fermented dough by MRS medium and M17 medium. Through the observation of colony and mycelia morphologies and physiological and biochemical experiment, the strain 1 was Lactobacillus plantarum, the strain 2 was Streptococcus thermophilus.%  利用MRS和M17培养基,从自然发酵面团中分离纯化出2株乳酸菌菌株,通过菌落形态、菌体形态观察和生理生化试验鉴定,菌株1为植物乳杆菌(Lactobacillus plantarum),菌株2为嗜热链球菌(Streptococcus thermophilus)。

  11. Purification, crystallization and preliminary characterization of a putative LmbE-like deacetylase from Bacillus cereus

    International Nuclear Information System (INIS)

    The BC1534 protein from B. cereus was purified and crystallized and a native X-ray diffraction data set was collected to 2.5 Å using synchrotron radiation. The Bacillus cereus BC1534 protein, a putative deacetylase from the LmbE family, has been purified to homogeneity and crystallized using the hanging-drop vapour-diffusion method. Crystals of the 26 kDa protein grown from MPD and acetate buffer belong to space group R32, with unit-cell parameters a = b = 76.7, c = 410.5 Å (in the hexagonal setting). A complete native data set was collected to a resolution of 2.5 Å from a single cryoprotected crystal using synchrotron radiation. As BC1534 shows significant sequence homology with an LmbE-like protein of known structure from Thermus thermophilus, molecular replacement will be used for crystal structure determination

  12. Dicty_cDB: Contig-U14260-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ella pneumoniae 342, compl... 121 5e-26 CP000830_125( CP000830 |pid:none) Dinoroseobact...e) Pseudomonas aeruginosa PA7, com... 119 2e-25 CU928158_1328( CU928158 |pid:none) Escherichia fergusoni...ts) Value AC117072_14( AC117072 |pid:none) Dictyostelium discoideum chromoso... 378 e-103 CP000359_959( CP000359 |pid:none) Deino...l... 271 3e-71 CU207211_2398( CU207211 |pid:none) Herminiimonas arsenicoxydans ch... 270 6e-71 CP000891_2993( CP000891 |pid:non...e) Thermus thermophilus HB8 genomic... 261 5e-68 CU207211_11( CU207211 |pid:none) Herminiimonas arseni

  13. Electron-mediating Cu(A) centers in proteins

    DEFF Research Database (Denmark)

    Epel, Boris; Slutter, Claire S; Neese, Frank;

    2002-01-01

    -D structures and compared with the experimental spectra. It was found that the width of the powder patterns of the weakly coupled protons recorded at g(perpendicular) is mainly determined by the histidine H(epsilon)(1) protons. Furthermore, the splitting in the outer wings of these powder patterns...... subunit II of Thermus thermophilus cytochrome c oxidase (COX) ba(3) (M160T9), its M160QT0 mutant, where the weak axial methionine ligand has been replaced by a glutamine, and the engineered "purple" azurin (purpAz). The three-dimensional (3-D) structures of these proteins, apart from the mutant, are known...... copper hyperfine interaction. Comparison of the best-fit anisotropic hyperfine parameters with those calculated from dipolar interactions extracted from the available 3-D structures sets limit to the sulfur spin densities. Similarly, the small coupling spectral region was simulated on the basis of the 3...

  14. Site-specific Incorporation of 3-Iodo-L-tyrosine into Proteins and Single-wavelength Anomalous Dispersion Phasing with Soft X-ray in Protein Crystallography

    Science.gov (United States)

    Murayama, Kazutaka; Sakamoto, Kensaku

    Iodine is a good anomalous scatter for radiations from in-house X-ray generators (Cu/CrKα). Non-natural amino acid, 3-iodo-L-tyrosine, is able to be site-specifically incorporated into proteins with amber suppresser tRNA and mutated TyrRS from M. jannaschii in the E. coli expression system. To determine the crystal structure of acetyl transferase from T. thermophilus, iodotyrosine-containing proteins were prepared and crystallized. Structure determination was successfully conducted with the protein variant with iodotyrosine at position 111. Anomalous signals from iodotyrosine with Cu/CrKα radiations were both sufficient to calculate clear electron density map. In the crystal structure, iodotyrosine did not significantly disturb the native structure.

  15. Changes in oxidation-reduction potential during milk fermentation by wild lactic acid bacteria.

    Science.gov (United States)

    Morandi, Stefano; Silvetti, Tiziana; Tamburini, Alberto; Brasca, Milena

    2016-08-01

    Oxidation-reduction potential (E h) is a fundamental physicochemical property of lactic acid bacteria that determines the microenvironment during the cheese manufacture and ripening. For this reason the E h is of growing interest in dairy research and the dairy industry. The objective of the study was to perform a comprehensive study on the reduction activity of wild lactic acid bacteria strains collected in different periods (from 1960 to 2012) from Italian dairy products. A total of 709 strains belonging to Lactococcus lactis, Enterococcus durans, E. faecium, E. faecalis and Streptococcus thermophilus species were studied for their reduction activity in milk. Kinetics of milk reduction were characterised by the minimum redox potential (E h7) and time of reaching E h7 (t min), the maximum difference between two measures (Δmax) and the time at which these maximum differences occurred (t*). Broad diversity in kinetic parameters was observed at both species and strain levels. E. faecalis and L. lactis resulted to be the most reducing species, while S. thermophilus was characterised by the lowest reducing power while the greatest heterogeneity was pointed out among E. durans and E. faecium strains. Considering the period of collection (1960-2012) we observed that the more recently isolated strains generally showed less reducing activity. This trend was particularly evident for the species E. durans, E. faecium and L. lactis while an opposite trend was observed in E. faecalis species. Data reported in this research provide new information for a deeper understanding of redox potential changes during milk fermentation due to bacterial growth. Gain knowledge of the redox potential of the LAB cultures could allow a better control and standardisation of cheesemaking process. PMID:27600976

  16. Identification and characterisation of an iron-responsive candidate probiotic.

    Directory of Open Access Journals (Sweden)

    Jennifer R Bailey

    Full Text Available BACKGROUND: Iron is an essential cofactor in almost all biological systems. The lactic acid bacteria (LAB, frequently employed as probiotics, are unusual in having little or no requirement for iron. Iron in the human body is sequestered by transferrins and lactoferrin, limiting bacterial growth. An increase in the availability of iron in the intestine by bleeding, surgery, or under stress leads to an increase in the growth and virulence of many pathogens. Under these high iron conditions, LAB are rapidly out-competed; for the levels of probiotic bacteria to be maintained under high iron conditions they must be able to respond by increasing growth rate to compete with the normal flora. Despite this, iron-responsive genera are poorly characterised as probiotics. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that a panel of probiotics are not able to respond to increased iron availability, and identify an isolate of Streptococcus thermophilus that can increase growth rate in response to increased iron availability. The isolate of S. thermophilus selected was able to reduce epithelial cell death as well as NF-κB signalling and IL-8 production triggered by pathogens. It was capable of crossing an epithelial cell barrier in conjunction with E. coli and downregulating Th1 and Th17 responses in primary human intestinal leukocytes. CONCLUSIONS/SIGNIFICANCE: We propose that an inability to compete with potential pathogens under conditions of high iron availability such as stress and trauma may contribute to the lack of efficacy of many LAB-based probiotics in treating disease. Therefore, we offer an alternative paradigm which considers that probiotics should be able to be competitive during periods of intestinal bleeding, trauma or stress.

  17. Role of antioxidant enzymes in bacterial resistance to organic acids.

    Science.gov (United States)

    Bruno-Bárcena, Jose M; Azcárate-Peril, M Andrea; Hassan, Hosni M

    2010-05-01

    Growth in aerobic environments has been shown to generate reactive oxygen species (ROS) and to cause oxidative stress in most organisms. Antioxidant enzymes (i.e., superoxide dismutases and hydroperoxidases) and DNA repair mechanisms provide protection against ROS. Acid stress has been shown to be associated with the induction of Mn superoxide dismutase (MnSOD) in Lactococcus lactis and Staphylococcus aureus. However, the relationship between acid stress and oxidative stress is not well understood. In the present study, we showed that mutations in the gene coding for MnSOD (sodA) increased the toxicity of lactic acid at pH 3.5 in Streptococcus thermophilus. The inclusion of the iron chelators 2,2'-dipyridyl (DIP), diethienetriamine-pentaacetic acid (DTPA), and O-phenanthroline (O-Phe) provided partial protection against 330 mM lactic acid at pH 3.5. The results suggested that acid stress triggers an iron-mediated oxidative stress that can be ameliorated by MnSOD and iron chelators. These findings were further validated in Escherichia coli strains lacking both MnSOD and iron SOD (FeSOD) but expressing a heterologous MnSOD from S. thermophilus. We also found that, in E. coli, FeSOD did not provide the same protection afforded by MnSOD and that hydroperoxidases are equally important in protecting the cells against acid stress. These findings may explain the ability of some microorganisms to survive better in acidified environments, as in acid foods, during fermentation and accumulation of lactic acid or during passage through the low pH of the stomach. PMID:20305033

  18. Identification and Characterization of the Nickel Uptake System for Urease Biogenesis in Streptococcus salivarius 57.I

    Science.gov (United States)

    Chen, Yi-Ywan M.; Burne, Robert A.

    2003-01-01

    Ureases are multisubunit enzymes requiring Ni2+ for activity. The low pH-inducible urease gene cluster in Streptococcus salivarius 57.I is organized as an operon, beginning with ureI, followed by ureABC (structural genes), and ureEFGD (accessory genes). Urease biogenesis also requires a high-affinity Ni2+ uptake system. By searching the partial genome sequence of a closely related organism, Streptococcus thermophilus LMG18311, three open reading frame (ORFs) homologous to those encoding proteins involved in cobalamin biosynthesis and cobalt transport (cbiMQO) were identified immediately 3′ to the ure operon. To determine whether these genes were involved in urease biogenesis by catalyzing Ni2+ uptake in S. salivarius, regions 3′ to ureD were amplified by PCRs from S. salivarius by using primers identical to the S. thermophilus sequences. Sequence analysis of the products revealed three ORFs. Reverse transcriptase PCR was used to demonstrate that the ORFs are transcribed as part of the ure operon. Insertional inactivation of ORF1 with a polar kanamycin marker completely abolished urease activity and the ability to accumulate 63Ni2+ during growth. Supplementation of the growth medium with NiCl2 at concentrations as low as 2.5 μM partially restored urease activity in the mutant. Both wild-type and mutant strains showed enhanced urease activity when exogenous Ni2+ was provided at neutral pH. Enhancement of urease activity by adding nickel was regulated at the posttranslational level. Thus, ORF1, ORF2, and ORF3 are part of the ure operon, and these genes, designated ureM, ureQ, and ureO, respectively, likely encode a Ni2+-specific ATP-binding cassette transporter. PMID:14617641

  19. The influence of the cell free solution of lactic acid bacteria on tyramine production by food borne-pathogens in tyrosine decarboxylase broth.

    Science.gov (United States)

    Toy, Nurten; Özogul, Fatih; Özogul, Yesim

    2015-04-15

    The function of cell-free solutions (CFSs) of lactic acid bacteria (LAB) on tyramine and other biogenic amine production by different food borne-pathogens (FBPs) was investigated in tyrosine decarboxylase broth (TDB) using HPLC. Cell free solutions were prepared from four LAB strains. Two different concentrations which were 50% (5 ml CFS+5 ml medium/1:1) and 25% (2.5 ml CFS+7.5 ml medium/1:3) CFS and the control without CFS were prepared. Both concentration of CFS of Streptococcus thermophilus and 50% CFS of Pediococcus acidophilus inhibited tyramine production up to 98% by Salmonella paratyphi A. Tyramine production by Escherichia coli was also inhibited by 50% CFS of Lactococcus lactis subsp. lactis and 25% CFS of Leuconostoc lactis. subsp. cremoris. The inhibitor effect of 50% CFS of P. acidophilus was the highest on tyramine production (55%) by Listeria monocytogenes, following Lc. lactis subsp. lactis and Leuconostoc mesenteroides subsp. cremoris (20%) whilst 25% CFS of Leu. mes. subsp. cremoris and Lc. lactis subsp. lactis showed stimulator effects (160%). The stimulation effects of 50% CFS of S. thermophilus and Lc. lactis subsp. lactis were more than 70% by Staphylococcus aureus comparing to the control. CFS of LAB strains showed statistically inhibitor effect since lactic acid inhibited microbial growth, decreased pH quickly and reduced the formation of AMN and BAs. Consequently, in order to avoid the formation of high concentrations of biogenic amines in fermented food by bacteria, it is advisable to use CFS for food and food products. PMID:25465993

  20. Effect of green tea supplementation on the microbiological, antioxidant, and sensory properties of probiotic milks.

    Science.gov (United States)

    Najgebauer-Lejko, Dorota

    2014-01-01

    Green tea and its constituents are known for a wide range of health-promoting properties. They may exert antimicrobial action but without altering lactic acid bacteria. The aim of the present study was to estimate the effect of green tea addition on the selected properties of probiotic milks. Bioyogurts (fermented with ABT-1 coculture of Streptococcus thermophilus, Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12) and acidophilus milks (fermented with pure L. acidophilus LA-5 culture) with addition of 0, 5, 10, or 15% (v/v) green tea infusion (GTI) were produced and analyzed for the antioxidant capacity by the "diphenyl picrylhydrazyl" (DPPH) and "ferric-reducing antioxidant power" (FRAP) methods, acidity, the count of starter bacteria, and sensory properties at the 1st, 7th, 14th, and 21st day of cold storage. The 15% addition of GTI to the acidophilus milk significantly reduced the lactic acid production during the whole study. The GTI had no impact on the level of S. thermophilus and B. lactis BB-12 in bioyogurts, and its effect on the count of L. acidophilus LA-5 depended on the concentration and probiotic milk type. GTI similarly and in a dose-dependent manner enhanced the antioxidant capacity of both milk types. There were no significant differences between the sensory notes received for bioyogurts, whereas acidophilus milks with tea were less appreciated by the panelists. In conclusion, green tea could be successfully used as a functional additive for selected probiotic milks enhancing their health benefits, but the proper selection of tea additive and starter culture is recommended. PMID:24883178

  1. Drink fermented to the base of serum of milk and isolated soy protein / Bebida fermentada à base de soro de leite e isolado protéico de soja

    Directory of Open Access Journals (Sweden)

    Ivone Yurika Mizubuti

    2000-04-01

    Full Text Available The whey and soy protein were used as substrate to obtain a basic beverage, fermented by yogurt culture (Lactobacillus delbrueckii subsp. buigaricus / Streptococcus salivarius subsp. thermophilus YC-180 and by probiotic culture (Lactobacillus acidophilus La-5. The formulation ( whey 10g/100mL; soy protein 2,4 g/100mL; fiber 0,5 g/100mL and sucrose 15 g/100mL was fermented separately, and mixed (1:1 to obtain the final fermented product with 0.72% (lactic acid acidity, pH 4.3 and lactic acid bacteria count of 2,0 x 108 cfu/mL, adequate for production of the proposed beverage.O soro de leite e o isolado protéico de soja foram utilizados para obtenção de uma bebida base, fermentada com cultura de iogurte (Lactobacillus delbrueckii subsp. bulgaricus / Streptococcus salivarius subsp. thermophilus YC - 180 e cultura probiótica (Lactobacillus acidophilus La-5. A formulação (soro de leite 10 g/100mL; isolado protéico de soja 2,4 g/100mL; fibras 0,5 g/100mL e sacarose 15 g/100mL indicou que procedendo-se a fermentação seguida de mistura na proporção de 1:1, produziu-se um produto final com acidez de 0,72% de ácido láctico; pH 4,3 e contagem de bactérias lácticas de 2,0 x 108 ufc/mL adequado para a obtenção da bebida proposta.

  2. Lactose fermentation at Camembert, made by classic and stabilised

    Directory of Open Access Journals (Sweden)

    Bogdan Perko

    2002-01-01

    Full Text Available In our experiments the fermentation of lactose at Camembert type cheese by classic and stabilised technology was monitored. In each of the two technologies two experiments were made. The difference between these two technologies is in pH level, which drops below 5 by classic technology and remains above 5 by stabilised technology at all times. To achieve the criteria of stabilised technology the fermentation was stopped at a desired level of pH, by dropping the cheese in brine at 14 °C. After salting and moulding cheesewas transferred from the first three experiments into a ripening chamber at 11 °C. With the last experiment (stabilised technology the cheese ripened for 3 days at 5 °C. During ripening process pH dropped below 5 in all experiments. The process of fermentation was performed by the following lactic acid bacteria: Streptococcus thermophilus, Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris. As these lactic acid bacteria ferment differently D-galactose during manufacture and ripening process, the contentof lactose and D-galactose was measured. Based on the results of our research the following conclusion can be made: the action of lactic acid bacteria can not be stropped even at 5 °C. The native microflora, which remains in the milk after thermisation, might be responsible for the fermentation of Dgalactose. It could be possible that the Streptococcus thermophilus enzymes were not inactivated, causing continuation of lactose fermentation even at low temperature. Mesophilic lactococci were inhibited and for that reason Dgalactose accumulated in cheese. Only after cheese were transferred into a ripening chamber at 11 °C and with low lactose concentration in medium left, mesophilic lactococci started to ferment D-galactose.

  3. Diversity of lactic acid bacteria associated with traditional fermented dairy products in Mongolia.

    Science.gov (United States)

    Yu, J; Wang, W H; Menghe, B L G; Jiri, M T; Wang, H M; Liu, W J; Bao, Q H; Lu, Q; Zhang, J C; Wang, F; Xu, H Y; Sun, T S; Zhang, H P

    2011-07-01

    Spontaneous milk fermentation has a long history in Mongolia, and beneficial microorganisms have been handed down from one generation to the next for use in fermented dairy products. The objective of this study was to investigate the diversity of lactic acid bacteria (LAB) communities in fermented yak, mare, goat, and cow milk products by analyzing 189 samples collected from 13 different regions in Mongolia. The LAB counts in these samples varied from 3.41 to 9.03 log cfu/mL. Fermented yak and mare milks had almost identical mean numbers of LAB, which were significantly higher than those in fermented goat milk but slightly lower than those in fermented cow milk. In total, 668 isolates were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. Each isolate was considered to be presumptive LAB based on gram-positive and catalase-negative properties, and was identified at the species level by 16S rRNA gene sequencing, multiplex PCR assay, and restriction fragment length polymorphism analysis. All isolates from Mongolian dairy products were accurately identified as Enterococcus faecalis (1 strain), Enterococcus durans (3 strains), Lactobacillus brevis (3 strains), Lactobacillus buchneri (2 strains), Lactobacillus casei (16 strains), Lactobacillus delbrueckii ssp. bulgaricus (142 strains), Lactobacillus diolivorans (17 strains), Lactobacillus fermentum (42 strains), Lactobacillus helveticus (183 strains), Lactobacillus kefiri (6 strains), Lactobacillus plantarum ssp. plantarum (7 strains), Lactococcus lactis ssp. lactis (7 strains), Leuconostoc lactis (22 strains), Leuconostoc mesenteroides (21 strains), Streptococcus thermophilus (195 strains), and Weissella cibaria (1 strain). The predominant LAB were Strep. thermophilus and Lb. helveticus, which were isolated from all sampling sites. The results demonstrate that traditional fermented dairy products from different regions of Mongolia have complex compositions of LAB species. Such diversity of

  4. Antimicrobial effectiveness evaluation of natural microorganism source preservatives used for cosmetic formulation%化妆品用微生物源天然防腐剂的抑菌效能研究

    Institute of Scientific and Technical Information of China (English)

    李馨恩; 何秋星; 区梓聪; 方电力; 关建云; 赵红

    2015-01-01

    以微生物源的嗜热链球菌发酵产物和曲霉发酵产物作为研究对象,根据其抑菌作用进行复配研究,参考美国个人护理品委员会(PCPC)的抑菌效能测试方法对乳液配方进行微生物挑战试验。结果表明,在乳液配方中,质量分数为0.5%的嗜热链球菌发酵产物和0.3%曲霉发酵产物可以使配方中的微生物菌落数在第14天降到100 CFU/g以下,可通过微生物挑战试验。%Two kinds of new natural microorganism source preservatives nominated Streptococus thermophilus Ferment and Aspergillus Ferment were taken as the object for research work. Formulation study based upon the bacterial inhibition action of the aforesaid preservatives was carried out. With reference of the bacterial inhibition efficacy test method of the American Personal Care Product Committee (PCPC),microbial challenge tests for emulsion formulations were processed. The test results demonstrated that an emulsion consisting of Streptococus thermophilus Ferment at 0.5% of mass fraction and Aspergillus Ferment at 0.3% of mass fraction can reduce the amount of microbial to be lower than 100 CFU/g on the 14th day and can pass the microbial challenge test meanwhile.

  5. Characterization of bifunctional L-glutathione synthetases from Actinobacillus pleuropneumoniae and Actinobacillus succinogenes for efficient glutathione biosynthesis.

    Science.gov (United States)

    Yang, Jianhua; Li, Wei; Wang, Dezheng; Wu, Hui; Li, Zhimin; Ye, Qin

    2016-07-01

    Glutathione (GSH), an important bioactive substance, is widely applied in pharmaceutical and food industries. In this work, two bifunctional L-glutathione synthetases (GshF) from Actinobacillus pleuropneumoniae (GshFAp) and Actinobacillus succinogenes (GshFAs) were successfully expressed in Escherichia coli BL-21(DE3). Similar to the GshF from Streptococcus thermophilus (GshFSt), GshFAp and GshFAs can be applied for high titer GSH production because they are less sensitive to end-product inhibition (Ki values 33 and 43 mM, respectively). The active catalytic forms of GshFAs and GshFAp are dimers, consistent with those of GshFPm (GshF from Pasteurella multocida) and GshFSa (GshF from Streptococcus agalactiae), but are different from GshFSt (GshF from S. thermophilus) which is an active monomer. The analysis of the protein sequences and three dimensional structures of GshFs suggested that the binding sites of GshFs for substrates, L-cysteine, L-glutamate, γ-glutamylcysteine, adenosine-triphosphate, and glycine are highly conserved with only very few differences. With sufficient supply of the precursors, the recombinant strains BL-21(DE3)/pET28a-gshFas and BL-21(DE3)/pET28a-gshFap were able to produce 36.6 and 34.1 mM GSH, with the molar yield of 0.92 and 0.85 mol/mol, respectively, based on the added L-cysteine. The results showed that GshFAp and GshFAs are potentially good candidates for industrial GSH production. PMID:26996628

  6. Optimization of fermentation process in skim milk with ST-ⅢLactobacillus plantarum%植物乳杆菌ST-Ⅲ脱脂乳的发酵工艺优化

    Institute of Scientific and Technical Information of China (English)

    华宝珍; 李莎; 徐爱才; 徐志平; 马成杰

    2014-01-01

    Fermented milk is increasingly used as a carrier of probiotics for their potential health functions. Because the concentration of viable probiotics is the key factor to health functions, it should be higher than the recommended concentration for probiotics (106 CFU/g). However, there are many products with low viability of probiotics in the market. It is very important and necessary for the milk industry to increase the count of viable probiotics in yogurt. In addition, survival during the passage through the gastrointestinal tract is generally considered a key feature for probiotics to preserve their expected health functions. However, the traditional yogurt starters (Streptococcus thermophilus and Lactobacillus bulgaricus) have weak tolerance to acid and bile salt and hence limit therapeutic effects. Lactobacillus plantarum has been demonstrated that it can survive in the human intestine and tolerate acid and bile salt. Moreover, it has a lot of precious therapeutic effects, such as precipitating and assimilating cholesterols, lowering blood sugar, diminishing inflammation and improving immunity. Hence, L.plantarumhas become one of research hotspots in recent years. Lactobacillus plantarum ST-Ⅲ strain (CGMCC No.0847) is a probiotics and has ability to tolerate acid and bile salts as well as grow in the lower intestinal tract. It also be proved to have ability to precipitate and assimilate cholesterols in vitro andin vivo. However L.plantarumST-Ⅲ strain is auxotrophic and has weak ability to grow in skim milk and clot milk by acidification. In this study, to increase the concentration of viableL.plantarumST-Ⅲ and elucidate the factors restricting growth ofL.plantarumST-Ⅲ in skim milk, the fermentation conditions were researched and optimized. The effects of soybean polypeptide concentration, manganese gluconate concentration, inoculum size of S. thermophilus and fermentation temperature on the pH and living cell count ofL.plantarumST-Ⅲ of fermented milk

  7. Prevalence and comparison of Streptococcus infantarius subsp. infantarius and Streptococcus gallolyticus subsp. macedonicus in raw and fermented dairy products from East and West Africa

    Science.gov (United States)

    Jans, Christoph; Kaindi, Dasel Wambua Mulwa; Böck, Désirée; Njage, Patrick Murigu Kamau; Kouamé-Sina, Sylvie Mireille; Bonfoh, Bassirou; Lacroix, Christophe; Meile, Leo

    2016-01-01

    Streptococcus infantarius subsp. infantarius (Sii) and Streptococcus gallolyticus subsp. macedonicus are members of the Streptococcus bovis/Streptococcus equinus complex (SBSEC) associated with human infections. SBSEC-related endocarditis was furthermore associated with rural residency in Southern Europe. SBSEC members are increasingly isolated as predominant species from fermented dairy products in Europe, Asia and Africa. African variants of Sii displayed dairy adaptations to lactose metabolism paralleling those of Streptococcus thermophilus including genome decay. In this study, the aim was to assess the prevalence of Sii and possibly other SBSEC members in dairy products of East and West Africa in order to identify their habitat, estimate their importance in dairy fermentation processes and determine geographic areas affected by this potential health risk. Presumptive SBSEC members were isolated on semi-selective M17 and SM agar media. Subsequent genotypic identification of isolates was based on rep-PCR fingerprinting and SBSEC-specific16S rRNA gene PCR assay. Detailed identification was achieved through application of novel primers enhancing the binding stringency in partial groES/groEL gene amplification and subsequent DNA sequencing. The presence of S. thermophilus-like lacS and lacZ genes in the SBSEC isolates was determined to elucidate the prevalence of this dairy adaptation. Isolates (n = 754) were obtained from 72 raw and 95 fermented milk samples from Côte d'Ivoire and Kenya on semi-selective agar media. Colonies of Sii were not detected from raw milk despite high microbial titers of approximately 106 CFU/mL on M17 agar medium. However, after spontaneous milk fermentation Sii was genotypically identified in 94.1% of Kenyan samples and 60.8% of Kenyan isolates. Sii prevalence in Côte d'Ivoire displayed seasonal variations in samples from 32.3% (June) to 40.0% (Dec/Jan) and isolates from 20.5% (June) to 27.7% (Dec/Jan) present at titers of 106–108

  8. REDUÇÃO DE NÍVEIS DE OLIGOSSACÁRIDES EM “IOGURTE” DE SOJA PELO USO DE CULTURAS LÁTICAS

    Directory of Open Access Journals (Sweden)

    ELIZEU ANTôNIO ROSSI

    2007-02-01

    Full Text Available O Streptococcus thermophilus e o Lactobacillus bulgaricus, microorganismos tradicionalmente empregados na elaboração de iogurtes, não são capazes de reduzir satisfatoriamente os níveis de oligossacárides de “iogurtes” preparados à base de soja. Em razão disso, verificou-se o efeito da substituição e/ou associação dessas culturas láticas com culturas de Lactobacillus fermenti e Lactobacillus acidophilus. Nos diversos produtos obtidos foram determinados os níveis de estaquiose, rafinose e sacarose, além da aceitabilidade geral e textura (avaliações sensoriais, viscosidade e consistência. Foi também verificado o tempo de fermentação de cada produto. Com relação à estaquiose, os níveis encontrados nos “iogurtes” de soja representaram de 98 a 115% do nível original do meio de fermentação. A rafinose não foi detectada em nenhum dos produtos, enquanto a sacarose sofreu reduções que variaram de 55,5% a 68,0% do conteúdo inicial. Vários açúcares simples, dentre eles a galactose, foram verificados nos diferentes produtos acabados. Os resultados mostraram que a modificação do inóculo convencional de iogurte (S. thermophilus + L. bulgaricus, através de substituição ou associação com culturas de L. fermenti e L. acidophilus, não se mostrou como alternativa válida no sentido de reduzir oligossacárides. Por outro lado, nos produtos onde o L. bulgaricus foi substituído, verificou-se um significativo aumento do tempo de fermentação.

  9. Effects of yogurt starter cultures on the survival of Lactobacillus acidophilus.

    Science.gov (United States)

    Ng, Elizabeth W; Yeung, Marie; Tong, Phillip S

    2011-01-31

    Recognized to confer health benefits to consumers, probiotics such as Lactobacillus acidophilus are commonly incorporated into fermented dairy products worldwide; among which yogurt is a popular delivery vehicle. To materialize most of the putative health benefits associated with probiotics, an adequate amount of viable cells must be delivered at the time of consumption. However, the loss in their viabilities during refrigerated storage has been demonstrated previously. This study focused on the effects of yogurt starter cultures on the survival of five strains of L. acidophilus, with emphases on low pH and acid production. Differential survival behavior between L. acidophilus strains was further analyzed. To this end, viable cell counts of L. acidophilus were determined weekly during 4°C storage in various types of yogurts made with Streptococcus thermophilus alone, L. delbrueckii ssp. bulgaricus alone, both species of the starter cultures, or glucono-delta-lactone (GDL). All yogurt types, except for pasteurized yogurts, were co-fermented with L. acidophilus. Yogurt filtrate was analyzed for the presence of any inhibitory substance and for the amount of hydrogen peroxide. Multiplication of L. acidophilus was not affected by the starter cultures as all strains reached high level on day 0 of the storage period. Throughout the 28-day storage period, cell counts of L. acidophilus PIM703 and SBT2062 remained steady (~6 × 10(7)CFU/g) in yogurts made with both starter cultures, whereas those of ATCC 700396 and NCFM were reduced by a maximum of 3 and 4.6 logs, respectively. When starter cultures were replaced by GDL, all strains survived well, suggesting that a low pH was not a critical factor dictating their survival. In addition, the filtrate collected from yogurts made with starter cultures appeared to have higher inhibitory activities against L. acidophilus than that made with GDL. The presence of viable starter cultures was necessary to adversely affect the

  10. Lactic Acid and Probiotic Bacteria from Fermented and Probiotic Dairy Products

    Directory of Open Access Journals (Sweden)

    B.K.L. Karna

    2007-12-01

    Full Text Available Lactic acid and probiotic bacteria were enumerated and isolated from commercially available yoghurt andprobiotic milk products. Lactobacillus delbrueckii ssp. bulgaricus were enumerated and isolated usingMRS agar incubated anaerobically at 37oC for 72 hrs. M17 agar was used for the enumeration andisolation of Streptococcus thermophilus incubated aerobically at 37oC for 48 hrs. MRS agar and modifiedMRS agar (MRS + L-cysteine + LiCl + Na propionate were used for the enumeration and isolation ofprobiotic bacteria. Both were incubated anaerobically at 37oC for 72 hrs. Morphological, physiologicaland biochemical reactions were used to characterize the isolates.Str. thermophilus counts ranged from 2.6 x 1011 to 2.9 x 1020 CFU/g with Fruit Yoghurt (FY having thehighest count and Yoghurt Natural (YN with the lowest count. Highest Lactobacillus delbrueckii ssp.bulgaricus count was obtained in Duo Yoghurt (DY, 1.1 x 109 and lowest in Yoghurt Drink (YD, 8.0 x 107CFU/g. The highest probiotic bacterial count of 2.3 x 108 was obtained in Yakult (YK and Neslac (Nesshowed the lowest, 1.6 x 102 CFU/g. The viable counts of all the products examined met the prescribedminimum viable count of 105 to 106CFU/g for the claimed health benefits for the consumer except forChamyto Plain (CP, Nes and Nan-2 (Nan.Morphological, physiological and biochemical characteristics showed that the following genera andspecies were present Pediococcus acidilactici (YN, P. pentosaceus (FY, Lactobacillus delbrueckiidelbrueckii and L. brevis in Non Fat High Calcium Yoghurt (NC, L. acidophilus and L. delbrueckiidelbrueckii (DY, YD, P. damnosus and P. pentosaceus in Chamyto Orange (CO, L. delbrueckii bulgaricus,L. acidophilus, and L. delbrueckii delbrueckii (CP, L. para. paracasei (YK and Bifidobacterium ssp.(Nes and Nan.Of the 28 isolates characterized in this study, 15 were Lactobacillus (5 species, 5 werePediococcus (3 species, 6 were Bifidobacterium (species not identified, and 2 were

  11. 胡萝卜菠萝酸奶的研制%Development of Yoghurt with Carrot and Pineapple

    Institute of Scientific and Technical Information of China (English)

    张继成

    2012-01-01

    以鲜牛乳和胡萝卜、菠萝为主要原料,以保加利亚乳杆菌、嗜热链球菌和双歧杆菌作为发酵剂,采用感官品质评价和正交试验方法,研究胡萝卜菠萝酸奶的加工工艺.结果表明,胡萝卜菠萝酸奶加工制作的最佳配方及工艺条件为:在鲜牛乳中添加10%的胡萝卜和菠萝汁(胡萝卜汁∶菠萝汁=1∶2),8%的白砂糖,菌种添加量为4%(保加利亚乳杆菌∶嗜热链球菌∶双歧杆菌=1∶2∶1),在42 ℃下发酵4h,经冷却后熟后,制得的胡萝卜菠萝酸奶具有均匀的橙红色和独特的胡萝卜菠萝风味,其凝块均匀一致,表面细腻光滑,硬度、黏度适中,酸甜可口,清爽润喉,无异味,无或有少量的乳清析出,符合酸奶标准.%Using fresh milk, carrots and pineapples as the main raw materials, Lactobacillus bulgaricus, Streptococcus thermophilus and Bacillus bifidus as the starter, the processing technology of carrot pineapple yoghurt was studied, through sensory evaluation and orthogonal test method. The results showed that, the optimum formula and processing technology of carrot pineapple yoghurt were as follows: added 10% carrot and pineapple juice (carrot juice :pineapple juice = 1 -2) to fresh milk, 8% white sugar and 4% bacteria (Lactobacillus bulgaricus 'Streptococcus thermophilus: Bacillus bifidus = 1:2:1), fermented for 4 hours at 42 ℃ and then cooled down. The obtained carrot pineapple yoghurt had a uniform orange red color and clot, unique flavor of carrot and pineapple, smooth appearance, moderate hardness and viscosity, suitable acid and sweet flavor, no off-flavor, and no or a little of whey separtion, and was in line with the yogurt standard.

  12. CARACTERÍSTICAS FÍSICAS E QUÍMICAS DE BEBIDAS LÁCTEAS FERMENTADAS E PREPARADAS COM SORO DE QUEIJO MINAS FRESCAL

    Directory of Open Access Journals (Sweden)

    ALMEIDA Keila Emílio de

    2001-01-01

    Full Text Available Nesta pesquisa procurou-se verificar as características físicas e químicas de bebidas lácteas preparadas com três concentrações de soro de queijo Minas Frescal (30, 40 e 50%, empregando-se dois tipos de culturas lácticas: uma tradicional para iogurte (YC-180 contendo cepas mistas de Streptococcus salivarus subsp. thermophilus, Lactobacillus delbrueckii subsp. lactis e Lactobacillus delbrueckii subsp. bulgaricus e outra (ABY-1 contendo cepas mistas de Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophillus, Bifidobacteria e Streptococcus salivarius subsp. thermophilus. Constatou-se que as bebidas lácteas apresentaram diferença estatística no tempo zero para os teores de gordura e de extrato seco. À medida em que se elevou a proporção de soro em relação ao leite, os teores de gordura e de extrato seco diminuíram. O teor de proteína também diminuiu à medida em que se aumentou o teor de soro nas bebidas lácteas, embora a diferença não tenha sido tão acentuada quanto as observadas para os teores de gordura e de extrato seco. Em relação à lactose, não se constatou diferença entre os tratamentos. Os teores de soro não influenciaram o índice de proteólise das bebidas lácteas. Verificou-se todavia que as bebidas elaboradas com a cultura probiótica ABY-1 apresentaram valores superiores para proteólise quando comparadas às bebidas elaboradas com as culturas YC-180. As bebidas lácteas elaboradas com 30% de soro apresentaram maiores valores para viscosidade. As bebidas elaboradas com a cultura YC-180 apresentaram valores superiores para viscosidade durante o período de armazenamento.

  13. Textura instrumental de queijo petit-suisse potencialmente probiótico: influência de diferentes combinações de gomas Instrumental texture of probiotic petit-suisse cheese: influence of different combinations of gums

    Directory of Open Access Journals (Sweden)

    Larissa Yukie Maruyama

    2006-06-01

    Full Text Available O efeito de diferentes combinações de gomas sobre os parâmetros de textura instrumental de queijo tipo petit-suisse probiótico foi avaliado. Queijos petit-suisse foram produzidos utilizando-se massa-base de queijo quark preparada com o starter Streptococcus thermophilus e os probióticos Lactobacillus acidophilus e Bifidobacterium longum. Três formulações de queijo petit-suisse foram preparadas, a partir de massa-base de queijo quark adicionada de 0,75% do produto final da mistura de gomas - xantana (X, carragena (C, guar (G, pectina (P: F1 = 2,5X:2,5C:5G; F2 = 2X:3C:5P; F3 = 5C:5G. Os parâmetros avaliados após 1, 7, 14 e 21 dias de armazenamento do produto a 4±1ºC incluíram a contagem de probióticos, a textura instrumental, o pH e a umidade. As populações de probióticos mantiveram-se acima de 6,40 log UFC/g para L. acidophilus e de 7,30 log UFC/g para B. longum. Houve diferença significativa entre as formulações (pThe effect of different combinations of gums over texture parameters of probiotic petit-suisse cheese was evaluated. Petit-suisse cheeses were produced using Quark cheese-base prepared with the starter Streptococcus thermophilus and the probiotics Lactobacillus acidophilus and Bifidobacterium longum. Three formulations of petit-suisse were prepared, using the quark cheese-base added of 0.75% of the final product of the mixture of the hydrocolloids xanthan gum (X, carrageenan gum (C, guar gum (G, pectin (P: F1 = 2,5X:2,5C:5G; F2 = 2X:3C:5P; F3 = 5C:5G. Parameters evaluated after 1, 7, 14, and 21 days of storage of the product at 4±1ºC included microbial counts of probiotic microorganisms, instrumental texture parameters, pH and moisture. Probiotic counts were always above 6.40 log CFU/g for L. acidophilus and above 7.30 log CFU/g for B. longum. The formulations were significantly different (p<0.05 for all the texture parameters, except for firmness of F1. The pH and the moisture were similar for the three

  14. A hybrid zone between Bathymodiolus mussel lineages from eastern Pacific hydrothermal vents

    Directory of Open Access Journals (Sweden)

    Johnson Shannon B

    2013-01-01

    Full Text Available Abstract Background The inhabitants of deep-sea hydrothermal vents occupy ephemeral island-like habitats distributed sporadically along tectonic spreading-centers, back-arc basins, and volcanically active seamounts. The majority of vent taxa undergo a pelagic larval phase, and thus varying degrees of geographical subdivision, ranging from no impedance of dispersal to complete isolation, often exist among taxa that span common geomorphological boundaries. Two lineages of Bathymodiolus mussels segregate on either side of the Easter Microplate, a boundary that separates the East Pacific Rise from spreading centers connected to the Pacific-Antarctic Ridge. Results A recent sample from the northwest flank of the Easter Microplate contained an admixture of northern and southern mitochondrial haplotypes and corresponding alleles at five nuclear gene loci. Genotypic frequencies in this sample did not fit random mating expectation. Significant heterozygote deficiencies at nuclear loci and gametic disequilibria between loci suggested that this transitional region might be a ‘Tension Zone’ maintained by immigration of parental types and possibly hybrid unfitness. An analysis of recombination history in the nuclear genes suggests a prolonged history of parapatric contact between the two mussel lineages. We hereby elevate the southern lineage to species status as Bathymodiolus antarcticus n. sp. and restrict the use of Bathymodiolus thermophilus to the northern lineage. Conclusions Because B. thermophilus s.s. exhibits no evidence for subdivision or isolation-by-distance across its 4000 km range along the EPR axis and Galápagos Rift, partial isolation of B. antarcticus n. sp. requires explanation. The time needed to produce the observed degree of mitochondrial differentiation is consistent with the age of the Easter Microplate (2.5 to 5.3 million years. The complex geomorphology of the Easter Microplate region forces strong cross-axis currents that

  15. Textura instrumental e avaliação sensorial de queijo fresco cremoso simbiótico: implicações da adição de Lactobacillus paracasei e inulina Influence of Lactobacillus paracasei and inulin on instrumental texture and sensory evaluation of fresh cream cheese

    Directory of Open Access Journals (Sweden)

    Flávia Carolina Alonso Buriti

    2008-03-01

    Full Text Available Avaliou-se o efeito da adição do probiótico Lactobacillus paracasei e da fibra prebiótica inulina sobre o perfil de textura e as características sensoriais de queijo fresco cremoso. Três tratamentos de queijo fresco cremoso foram preparados em quintuplicata, em escala piloto, todos suplementados com uma cultura starter de Streptococcus thermophilus (T1, T2 e T3. L. paracasei subsp. paracasei foi adicionado em T1 e T2. Inulina foi adicionada em T2. O perfil de textura instrumental foi determinado após 1, 7, 14 e 21 dias de armazenamento. A análise sensorial foi conduzida aos 7 dias de armazenamento dos queijos. A presença de Lactobacillus paracasei nos queijos T1 e T2 e de inulina em T2 não alterou significativamente o perfil de textura (p>0,05. Os queijos T1 apresentaram a menor preferência na análise sensorial e diferiram significativamente de T2 e T3 (p0,05. A adição de inulina ao queijo fresco cremoso produzido com a suplementação de uma cepa potencialmente probiótica de Lactobacillus paracasei resultou em um produto com características adequadas e com propriedades funcionais agregadas.The influence of the addition of a potential probiotic culture of Lactobacillus paracasei and of the prebiotic fiber inulin on the texture profile and on the sensory evaluation of probiotic and synbiotic fresh cream-cheeses was monitored. Three cheese-making trials were prepared in quintuplicate, all supplemented with a Streptococcus thermophilus starter culture (T1, T2 and T3. L. paracasei subsp. paracasei was added to T1 and T2, and inulin, to T2. The instrumental texture profile was determined after 1, 7, 14 and 21 days of storage of the cheeses. Sensory evaluation was performed after 7 days of storage. The presence of Lactobacillus paracasei in cheeses T1 and T2 and of inulin in cheeses T2 did not alter the texture profile significantly. Cheeses T1 were the least preferred in the sensory evaluation and differed significantly from T2 and T3

  16. Effect of Total Inoculum Size Containing Lactobacillus acidophilus or Lactobacillus casei on Fermentation of Goat Milk

    Directory of Open Access Journals (Sweden)

    He Chen

    2015-02-01

    Full Text Available In order to obtain the optimum inoculum size of goat milk fermented by probiotics, the total inoculum size containing L. acidophilus or L. casei on pH, acidity and viable counts and sensory during fermentation were studied on the basis of S. thermophilus and L. bulgaricus as starter cultures. The results showed as follows: the optimum inoculum size of L. acidophilus or L. casei were all 7% and goat milk was fermented at 39°C for 4.5 h. The pH, acidity, the viable counts of L. acidophilus and the total viable counts were respectively 4.48, 91°T, 1.60×107 cfu/mL and 1.69×109 cfu/mL. The pH, acidity, the viable counts of L. casei and the total viable counts were respectively 4.38, 96°T, 2.80×108 cfu/mL and 2.20×109 cfu/mL.

  17. Spatiotemporal Control of Type III-A CRISPR-Cas Immunity: Coupling DNA Degradation with the Target RNA Recognition.

    Science.gov (United States)

    Kazlauskiene, Migle; Tamulaitis, Gintautas; Kostiuk, Georgij; Venclovas, Česlovas; Siksnys, Virginijus

    2016-04-21

    Streptococcus thermophilus (St) type III-A CRISPR-Cas system restricts MS2 RNA phage and cuts RNA in vitro. However, the CRISPR array spacers match DNA phages, raising the question: does the St CRISPR-Cas system provide immunity by erasing phage mRNA or/and by eliminating invading DNA? We show that it does both. We find that (1) base-pairing between crRNA and target RNA activates single-stranded DNA (ssDNA) degradation by StCsm; (2) ssDNase activity is confined to the HD-domain of Cas10; (3) target RNA cleavage by the Csm3 RNase suppresses Cas10 DNase activity, ensuring temporal control of DNA degradation; and (4) base-pairing between crRNA 5'-handle and target RNA 3'-flanking sequence inhibits Cas10 ssDNase to prevent self-targeting. We propose that upon phage infection, crRNA-guided StCsm binding to the emerging transcript recruits Cas10 DNase to the actively transcribed phage DNA, resulting in degradation of both the transcript and phage DNA, but not the host DNA. PMID:27105119

  18. Identifying and Visualizing Functional PAM Diversity across CRISPR-Cas Systems.

    Science.gov (United States)

    Leenay, Ryan T; Maksimchuk, Kenneth R; Slotkowski, Rebecca A; Agrawal, Roma N; Gomaa, Ahmed A; Briner, Alexandra E; Barrangou, Rodolphe; Beisel, Chase L

    2016-04-01

    CRISPR-Cas adaptive immune systems in prokaryotes boast a diversity of protein families and mechanisms of action, where most systems rely on protospacer-adjacent motifs (PAMs) for DNA target recognition. Here, we developed an in vivo, positive, and tunable screen termed PAM-SCANR (PAM screen achieved by NOT-gate repression) to elucidate functional PAMs as well as an interactive visualization scheme termed the PAM wheel to convey individual PAM sequences and their activities. PAM-SCANR and the PAM wheel identified known functional PAMs while revealing complex sequence-activity landscapes for the Bacillus halodurans I-C (Cascade), Escherichia coli I-E (Cascade), Streptococcus thermophilus II-A CRISPR1 (Cas9), and Francisella novicida V-A (Cpf1) systems. The PAM wheel was also readily applicable to existing high-throughput screens and garnered insights into SpyCas9 and SauCas9 PAM diversity. These tools offer powerful means of elucidating and visualizing functional PAMs toward accelerating our ability to understand and exploit the multitude of CRISPR-Cas systems in nature. PMID:27041224

  19. Crystallization and preliminary crystallographic analysis of the major capsid proteins VP16 and VP17 of bacteriophage P23-77

    International Nuclear Information System (INIS)

    The major capsid proteins VP16 and VP17 of bacteriophage P23-77 have been crystallized using both recombinant and purified virus and preliminary diffraction analyses have been performed. Members of the diverse double-β-barrel lineage of viruses are identified by the conserved structure of their major coat protein. New members of this lineage have been discovered based on structural analysis and we are interested in identifying relatives that utilize unusual versions of the double-β-barrel fold. One candidate for such studies is P23-77, an icosahedral dsDNA bacteriophage that infects the extremophile Thermus thermophilus. P23-77 has two major coat proteins, namely VP16 and VP17, of a size consistent with a single-β-barrel core fold. These previously unstudied proteins have now been successfully expressed as recombinant proteins, purified and crystallized using hanging-drop and sitting-drop vapour-diffusion methods. Crystals of coat proteins VP16 and VP17 have been obtained as well as of a putative complex. In addition, virus-derived material has been crystallized. Diffraction data have been collected to beyond 3 Å resolution for five crystal types and structure determinations are in progress

  20. Structures and reaction mechanisms of the two related enzymes, PurN and PurU.

    Science.gov (United States)

    Sampei, Gen-ichi; Kanagawa, Mayumi; Baba, Seiki; Shimasaki, Toshiaki; Taka, Hiroyuki; Mitsui, Shohei; Fujiwara, Shinji; Yanagida, Yuki; Kusano, Mayumi; Suzuki, Sakiko; Terao, Kayoko; Kawai, Hiroya; Fukai, Yoko; Nakagawa, Noriko; Ebihara, Akio; Kuramitsu, Seiki; Yokoyama, Shigeyuki; Kawai, Gota

    2013-12-01

    The crystal structures of glycinamide ribonucleotide transformylases (PurNs) from Aquifex aeolicus (Aa), Geobacillus kaustophilus (Gk) and Symbiobacterium toebii (St), and of formyltetrahydrofolate hydrolase (PurU) from Thermus thermophilus (Tt) were determined. The monomer structures of the determined PurN and PurU were very similar to the known structure of PurN, but oligomeric states were different; AaPurN and StPurN formed dimers, GkPurN formed monomer and PurU formed tetramer in the crystals. PurU had a regulatory ACT domain in its N-terminal side. So far several structures of PurUs have been determined, yet, the mechanisms of the catalysis and the regulation of PurU have not been elucidated. We, therefore, modelled ligand-bound structures of PurN and PurU, and performed molecular dynamics simulations to elucidate the reaction mechanisms. The evolutionary relationship of the two enzymes is discussed based on the comparisons of the structures and the catalytic mechanisms. PMID:24108189

  1. Composition of Hydrothermal Vent Microbial Communities as Revealed by Analyses of Signature Lipids, Stable Carbon Isotopes and Aquificales Cultures

    Science.gov (United States)

    Jahnke, Linda L.; Eder, Wolfgang; Huber, Robert; Hinrichs, Kai-Uwe; Hayes, John M.; Cady, Sherry L.; DesMarais, David J.; Hope, Janet M.; Summons, Roger E.

    2001-01-01

    Extremely thermophilic microbial communities associated with the siliceous vent walls and outflow channel of Octopus Spring, Yellowstone National Park, have been examined for lipid biomarker and carbon isotopic signatures. These data were compared with that obtained from representatives of three Aquificales genera. Thermocrinis ruber, Thermocrinis sp. HI, Hydrogenobacter thermophilus, Aquifex pyrophilus and Aquifex aeolicus all contained phospholipids composed not only of the usual ester-linked fatty acids, but also ether-linked alkyl moieties. The fatty acids of all cultured organisms were dominated by very distinct pattern of n-C-20:1 and cy-C-21 compounds. The alkyl glycerol ethers were present primarily as C-18:0 monoethers with the exception of the Aquifex spp. in which dialkyl glycerol ethers with a boarder carbon-number distribution were also present. These Aquificales biomarker lipids were the major constituents in the lipid extracts of the Octopus Spring microbial samples. Two natural samples, a microbial biofilm growing in association with deposition of amorphous silica on the vent walls at 92 C, and the well-known "pink-streamer community" (PSC), siliceous filaments of a microbial consortia growing in the outflow channel at 87 C were analyzed. Both the biofilm and PSC samples contained mono- and dialkyl glycerol ethers with a prevalence of C-18 and C-20 alkyls. Phospholipid fatty acids were comprised of both the characteristic. Additional information is contained in the original extended abstract.

  2. Harnessing functional food strategies for the health challenges of space travel—Fermented soy for astronaut nutrition

    Science.gov (United States)

    Buckley, Nicole D.; Champagne, Claude P.; Masotti, Adriana I.; Wagar, Lisa E.; Tompkins, Thomas A.; Green-Johnson, Julia M.

    2011-04-01

    Astronauts face numerous health challenges during long-duration space missions, including diminished immunity, bone loss and increased risk of radiation-induced carcinogenesis. Changes in the intestinal flora of astronauts may contribute to these problems. Soy-based fermented food products could provide a nutritional strategy to help alleviate these challenges by incorporating beneficial lactic acid bacteria, while reaping the benefits of soy isoflavones. We carried out strain selection for the development of soy ferments, selecting strains of lactic acid bacteria showing the most effective growth and fermentation ability in soy milk ( Streptococcus thermophilus ST5, Bifidobacterium longum R0175 and Lactobacillus helveticus R0052). Immunomodulatory bioactivity of selected ferments was assessed using an in vitro challenge system with human intestinal epithelial and macrophage cell lines, and selected ferments show the ability to down-regulate production of the pro-inflammatory cytokine interleukin-8 following challenge with tumour necrosis factor-alpha. The impact of fermentation on vitamin B1 and B6 levels and on isoflavone biotransformation to agluconic forms was also assessed, with strain variation-dependent biotransformation ability detected. Overall this suggests that probiotic bacteria can be successfully utilized to develop soy-based fermented products targeted against health problems associated with long-term space travel.

  3. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, Jennifer, E-mail: j.mahony@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Ainsworth, Stuart; Stockdale, Stephen [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Sinderen, Douwe van, E-mail: d.vansinderen@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Western Road, Cork (Ireland)

    2012-12-20

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

  4. Simultaneous assay of DNA and RNA targets in the whole blood using novel isolation procedure and molecular colony amplification.

    Science.gov (United States)

    Chetverina, Helena V; Falaleeva, Marina V; Chetverin, Alexander B

    2004-11-15

    A universal procedure that permits the whole human blood to be tested for the presence of single molecules of DNA and RNA targets is described. The procedure includes a novel protocol for the isolation of total nucleic acids from the guanidinium thiocyanate lysate of unfractionated blood in which, prior to phenol/chloroform extraction, the sample is deproteinized by precipitation with isopropanol. The procedure results in a nearly 100% yield of DNA and RNA, preserves the integrity of RNA, and removes any polymerase chain reaction (PCR) inhibitors. Following reverse transcription (RT), target molecules are counted after having been amplified as molecular colonies by carrying out PCR in a polyacrylamide gel. The entire procedure was checked by assaying viral DNA and RNA in 100-microl aliquots of the whole blood and was found to be capable of detecting 100% molecules of DNA target and 50% molecules of RNA target. Unexpectedly, nucleic acids at relatively high concentrations (1 ng/microl) were found to selectively inhibit the RT activity of Thermus thermophilus DNA polymerase without affecting its DNA-dependent polymerization activity. It follows that the popular single-enzyme RT-PCR format, in which this DNA polymerase serves for both RT and PCR, is not appropriate for assaying rare RNA targets. PMID:15494145

  5. CHOLESTEROL ASSIMILATION BY COMMERCIAL YOGHURT STARTER CULTURES

    Directory of Open Access Journals (Sweden)

    Małgorzata Ziarno

    2007-03-01

    Full Text Available The ability to in vitro cholesterol level reduction in laboratory media has been shown for numerous strains of lactic acid bacteria, but not for all strains of lactic bacteria used in the dairy industry. The aim of this work was the determination of the ability of selected thermophilic lactic acid bacteria to cholesterol assimilation during 24 h culture in MRS broth. Commercial starter cultures showed various ability to cholesterol assimilation from laboratory medium. In case of starter cultures used for production of traditional yoghurt, consisting of Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, the quantity of assimilated cholesterol did not exceed 27% of its initial contents (0.7 g in 1 dm3. Starter cultures used for bioyoghurt production, containing also probiotic strains (came from Lactobacillus acidophilus species or Bifidobacterium genus assimilated from almost 18% to over 38% of cholesterol. For one monoculture of Lb. acidophilus, cholesterol assimilation ability of 49-55% was observed, despite that the number of bacterial cells in this culture was not different from number of bacteria in other cultures.

  6. Identification and characterization of lactic acid bacteria isolated from artisanal white brined Golija cows’ milk cheeses

    Directory of Open Access Journals (Sweden)

    Terzić-Vidojević Amarela

    2014-01-01

    Full Text Available The aim of this study was to identify and characterize the lactic acid bacteria (LAB of artisanal Golija raw and cooked cows’ milk cheeses traditionally manufactured without the addition of starter culture. A total of 188 Gram-positive and catalase-negative isolates of Golija cheeses were obtained from seven samples of different ripening time. Phenotypebased assays as well as rep-PCR and 16S rDNA sequence analysis were undertaken for all 188 Lstrains. The most diverse species were isolated from 20-day-old BGGO8 cheese (Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus casei/paracasei, Lactobacillus sucicola, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis bv. diacetylactis, Enterococcus faecium, Enterococcus durans and Leuconostoc mesenteroides. In other Golija cheeses Lactobacillus reuteri, Lactobacillus curvatus, Lactobacillus rhamnosus, Lactococcus lactis subsp. cremoris, Lactococcus garvieae, Streptococcus thermophilus and Leuconostoc pseudomesenteroides were found. Pronounced antimicrobial properties showed enterococci (13/42 and lactococci (12/31, while the good proteolytic activity demonstrated lactococci (13/31 and lactobacilli (10/29. [Projekat Ministarstva nauke Republike Srbije, br. 173019

  7. Transfer, composition and technological characterization of the lactic acid bacterial populations of the wooden vats used to produce traditional stretched cheeses.

    Science.gov (United States)

    Scatassa, Maria Luisa; Gaglio, Raimondo; Macaluso, Giusi; Francesca, Nicola; Randazzo, Walter; Cardamone, Cinzia; Di Grigoli, Antonino; Moschetti, Giancarlo; Settanni, Luca

    2015-12-01

    The biofilms of 12 wooden vats used for the production of the traditional stretched cheeses Caciocavallo Palermitano and PDO Vastedda della valle del Belìce were investigated. Salmonella spp. and Listeria monocytogenes were never detected. Total coliforms were at low numbers with Escherichia coli found only in three vats. Coagulase-positive staphylococci (CPS) were below the enumeration limit, whereas lactic acid bacteria (LAB) dominated the surfaces of all vats. In general, the dominance was showed by coccus LAB. Enterococci were estimated at high numbers, but usually between 1 and 2 Log cycles lower than other LAB. LAB populations were investigated at species and strain level and for their technological properties relevant in cheese production. Eighty-five strains were analysed by a polyphasic genetic approach and allotted into 16 species within the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Streptococcus. Enterococcus faecium was found in all wooden vats and the species most frequently isolated were Enterococcus faecalis, Lactococcus lactis, Leuconostoc mesenteroides, Pediococcus acidilactici and Streptococcus thermophilus. The study of the quantitative data on acidification rate, autolysis kinetics, diacetyl production, antibacterial compound generation and proteolysis by cluster and principal component analysis led to the identification of some strains with promising dairy characteristics. Interestingly, a consistent percentage of LAB was bacteriocin-like inhibitory substances (BLIS) producer. Thus, the microbial biofilms of the wooden vats analysed in this study might contribute actively to the stability of the final cheeses. PMID:26338114

  8. Phages of lactic acid bacteria: the role of genetics in understanding phage-host interactions and their co-evolutionary processes.

    Science.gov (United States)

    Mahony, Jennifer; Ainsworth, Stuart; Stockdale, Stephen; van Sinderen, Douwe

    2012-12-20

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects. PMID:23089252

  9. Optimization Of Freeze-Dried Starter For Yogurt By Full Factorial Experimental Design

    Directory of Open Access Journals (Sweden)

    Chen He

    2015-12-01

    Full Text Available With the rapidly development of fermented milk product, it is significant for enhancing the performance of starter culture. This paper not only investigated the influence of anti-freeze factors and freeze-drying protective agents on viable count, freeze-drying survival rate and yield of Lactobacillus bulgaricus (LB and Streptococcus thermophilus (ST, but also optimized the bacteria proportion of freeze-dried starter culture for yogurt by full factorial experimental design. The results showed as following: the freeze-drying protective agents or anti-freeze factors could enhanced survival rate of LB and ST; the freeze-dried LB and ST powders containing both of anti-freeze factors and freeze-drying protective agents had higher viable count and freeze-drying survival rate that were 84.7% and 79.7% respectively; In terms of fermentation performance, the best group of freeze-dried starter for yogurt was the compound of LB3 and ST2.

  10. Change of lactose content after milk fermentation using various microbial cultures

    Directory of Open Access Journals (Sweden)

    Ivana Vinko

    2011-06-01

    Full Text Available The purpose of this study was to determine lactose and lactic acid content and acidity changes in typified milk prior to fermentation and in dairy products on 1st and 28th day of their storage at 8 °C in cold environment. In this study 5 different dairy products were observed: yogurt, extra lactose yogurt, bifido milk, sour cream and sour milk. The enzymatic method for determination of lactose has been used. The biggest change in lactose and lactic acid content, according to study results, has happened in the process of fermentation, as expected. About 16-20 % of lactose has been converted by mesophilus, while significantly bigger part (round 30 % of lactose to lactic acid has been converted by thermophilus. The smallest part of lactose conversion was performed by Bifidobacterium therapy culture (just 15 % after the first day and 19 % on 28th day of cold storage which is due to the greater adjustment period of Bifidobacterium in milk for lactose fermentation.

  11. 木瓜酸奶的加工工艺%Study on Process Technology of Papaya Yogurt

    Institute of Scientific and Technical Information of China (English)

    付红军

    2011-01-01

    The best craft for making papaya yogurt obtained through experiment was as follows, content of papaya slurry, 30%(m/m); white sugar consumption, 8%(m/m); Streptococcus thermophilus:Lactobacillus bulgaricus,1:1 (m':m); inoculum, 3%(m/m); fermentation temperature, 42℃; fermentation time, 6 h; compound stabilizer, CMC;PGA=0.30% :0.20%(m:m). Papaya yogurt prepared under these conditions was homogeneous, with exquisite taste and moderate sour.%通过对木瓜酸奶的加工工艺进行试验,得出其最优配方为木瓜浆质量分数30%,白砂糖用量(m/m,下同)8%,嗜热链球菌∶保加利亚乳杆菌(m∶m,下同)1.0∶1.0,接种量(m/m,下同)3%,发酵温度42℃,发酵时间6h,最佳复合稳定剂为羧甲基纤维素钠(CMC)(m/m,下同)∶海藻酸丙二醇酯(PGA)(m/m,下同)=0.30%∶0.20%,制得的木瓜酸奶组织均匀,口感细腻,酸甜适度.

  12. 马铃薯酸奶生产工艺优化%Process Optimization for the Development of Potato Yogurt

    Institute of Scientific and Technical Information of China (English)

    高杨

    2012-01-01

    以马铃薯和脱脂奶粉为主要原料,利用保加利亚乳杆菌和嗜热链球菌组成的混合发酵剂进行乳酸发酵。以感官评价为考察指标,通过正交试验研究确定马铃薯酸奶的最佳发酵工艺参数为:白砂糖加入量8%、发酵时间6h、发酵温度43℃。此工艺制备的马铃薯酸奶,色泽均匀,组织状态较好,口感细腻,符合标准要求。%The water left over from cooking potato and milk powder were used mainly for yogurt production by fermentation with mixed starter cultures of Lactobacillus bulgaria and Streptococcus thermophilus. The optimal fermentation parameters were 8% of white sugar, 6 h of fermentation time and 43 °C of fermentation temperature as determined using orthogonal array design for maximizing sensory evaluation score. Yogurt with a uniform color, a good texture, and a smooth taste was obtained under these parameters. Which could meet the requirements of relevant standards.

  13. Optimization of Production Technology of Konjac Yogurt by Response Surface Methodology%响应面法优化魔芋酸奶工艺

    Institute of Scientific and Technical Information of China (English)

    葛谦; 袁亚宏; 岳田利

    2013-01-01

      以魔芋精粉、牛奶为主要原料,通过单因素试验及BOX-Behnken设计法对魔芋固体酸奶进行了初步研究。结果表明,嗜热链球菌和保加利亚乳杆菌比例为2∶1,接种量为3.5%(体积分数),魔芋精粉添加量为0.08%,蔗糖添加量为质量分数7.9%,43℃发酵4.5 h,其获得产品组织均匀、口感细腻、风味俱佳。%With milk and konjac as main materials,the processing technology of konjac yogurt was studied by single factor and box-behnken experimental design.The results showed that excellent quality konjac yogurt could be produced under the conditions of 3.5%fermentation agent (2∶1 mixture of streptococcus thermophilus and lactobacillus bulgaricus),and konjac powder 0.08 %,sucrose 7.9 % and fermentation time 4.5 h under 43℃so that the konjac yogurt was homogeneous and smooth with appropriate sweetness andsourness.

  14. Efectos beneficiosos en niños sanos del consumo de un producto lácteo que contiene dos cepas probióticas: Lactobacillus coryniformis CECT5711 y Lactobacillus gasseri CECT5714 Beneficial effects of consumption of a dairy product containing two probiotic strains: Lactobacillus coryniformis CECT5711 and Lactobacillus gasseri CECT5714 in healthy children

    Directory of Open Access Journals (Sweden)

    F. Lara-Villoslada

    2007-08-01

    Full Text Available Objetivo o antecedente: En las últimas décadas la manipulación de la microbiota intestinal mediante el uso de probióticos ha adquirido un gran interés en el tratamiento y prevención de determinadas patologías infantiles. Además actualmente existen multitud de estudios que demuestran que las bacterias probióticas podrían tener un importante papel en el desarrollo del sistema inmunitario. Estudios recientes sugieren que dos cepas probióticas, Lactobacillus coryniformis CECT5711 y Lactobacillus gasseri CECT5714 mejoran la función intestinal de adultos sanos y potencian la respuesta inmunitaria. Dado que son muy pocos los estudios que analizan el papel de los probióticos en niños sanos, principales consumidores de estos productos, el objetivo del presente trabajo fue analizar los efectos de la administración conjunta de estas dos cepas probióticas en un producto lácteo fermentado en niños sanos. Intervenciones: Se reclutaron 30 niños de entre 3 y 12 años sin patología gastrointestinal conocida. Además de su dieta habitual, durante las 3 primeras semanas los niños recibieron 200 ml de un yogurt convencional que contenía Lactobacillus bulgaricus y Streptococcus thermophilus. A continuación este yogurt se sustituyó por 80 ml de un producto probiótico (Max Defensas® Puleva FOOD S.L. que contenía la misma cantidad de Streptococcus thermophilus y donde el L. bulgaricus fue substituido por la misma cantidad de una mezcla de las bacterias probióticas objeto del estudio: L. coryniformis CECT5711 y L. gasseri CECT5714. Se tomaron muestras de heces y de saliva al comienzo del estudio, a las 3 semanas y al finalizar el estudio. Durante estas 6 semanas los niños no tomaron otro yogurt o probiótico que no fueran los citados anteriormente. Se analizó la microbiotafecal de los niños, la toxicidad de las aguas fecales y la capacidad de éstas para inhibir la adhesión de Salmonella cholerasusis ssp. cholerasuis a mucinas

  15. Inhibition of NADH-ubiquinone reductase activity by N,N'-dicyclohexylcarbodiimide and correlation of this inhibition with the occurrence of energy-coupling site 1 in various organisms

    International Nuclear Information System (INIS)

    The NADH-ubiquinone reductase activity of the respiratory chains of several organisms was inhibited by the carboxyl-modifying reagent N,N'-dicyclohexylcarbodiimide (DCCD). This inhibition correlated with the presence of an energy-transducing site in this segment of the respiratory chain. Where the NADH-quinone reductase segment involved an energy-coupling site (e.g., in bovine heart and rat liver mitochondria, and in Paracoccus denitrificans, Escherichia coli, and Thermus thermophilus HB-8 membranes), DCCD acted as an inhibitor of ubiquinone reduction by NADH. By contrast, where energy-coupling site 1 was absent (e.g., in Saccharomyces cerevisiae mitochondria and BacilLus subtilis membranes), there was no inhibition of NADH-ubiquinone reductase activity by DCCD. In the bovine and P. denitrificans systems, DCCD inhibition was pseudo first order with respect to incubation time, and reaction order with respect to inhibitor concentration was close to unity, indicating that inhibition resulted from the binding of one inhibitor molecule per active unit of NADH-ubiquinone reductase. In the bovine NADH-ubiquinone reductase complex (complex I), [14C]DCCD was preferentially incorporated into two subunits of molecular weight 49,000 and 29,000. The time course of labeling of the 29,000 molecular weight subunit with [14C]DCCD paralleled the time course of inhibition of NADH-ubiquinone reductase activity

  16. Structural basis for the endoribonuclease activity of the type III-A CRISPR-associated protein Csm6

    Science.gov (United States)

    Niewoehner, Ole; Jinek, Martin

    2016-01-01

    Prokaryotic CRISPR–Cas systems provide an RNA-guided mechanism for genome defense against mobile genetic elements such as viruses and plasmids. In type III-A CRISPR–Cas systems, the RNA-guided multisubunit Csm effector complex targets both single-stranded RNAs and double-stranded DNAs. In addition to the Csm complex, efficient anti-plasmid immunity mediated by type III-A systems also requires the CRISPR-associated protein Csm6. Here we report the crystal structure of Csm6 from Thermus thermophilus and show that the protein is a ssRNA-specific endoribonuclease. The structure reveals a dimeric architecture generated by interactions involving the N-terminal CARF and C-terminal HEPN domains. HEPN domain dimerization leads to the formation of a composite ribonuclease active site. Consistently, mutations of invariant active site residues impair catalytic activity in vitro. We further show that the ribonuclease activity of Csm6 is conserved across orthologs, suggesting that it plays an important functional role in CRISPR–Cas systems. The dimer interface of the CARF domains features a conserved electropositive pocket that may function as a ligand-binding site for allosteric control of ribonuclease activity. Altogether, our work suggests that Csm6 proteins provide an auxiliary RNA-targeting interference mechanism in type III-A CRISPR–Cas systems that operates in conjunction with the RNA- and DNA-targeting endonuclease activities of the Csm effector complex. PMID:26763118

  17. Evidence for N coordination to Fe in the [2Fe-2S] clusters of Thermus Rieske protein and phthalate dioxygenase from Pseudomonas

    International Nuclear Information System (INIS)

    Rieske-type iron/sulfur proteins and several NADH-dependent oxygenases contain Fe/S clusters with similar spectral and magnetic properties. Purified Rieske iron/sulfur protein from Thermus thermophilus contains two apparently identical [2Fe-2S] clusters in a polypeptide having only four cysteine residues, and it has been proposed that each Fe/S cluster is coordinated to two cysteine S-atoms and to an unknown number of other non-sulfur atoms. The authors have examined the Rieske protein from Thermus and the phthalate dioxygenase from Pseudomonas cepacia with electron nuclear double resonance (ENDOR) and pulsed EPR methods and report here evidence for the direct coordination of nitrogenous ligands to the Fe/S clusters in these proteins. The electron nuclear double resonance signals arising from 14N have been interpreted in terms of a strongly coupled ligand with A/sup N/ = approx.26-28 MHz and a weakly coupled ligand with A/sup N/ = approx.9 MHz. The pulsed EPR spectrum shows a rich pattern of lines in the Fourier transformed data having peaks in the range of 0.8 to 6.7 MHz. The lower frequency resonances are tentatively associated with coupling of the unpaired spin to the remote N-atoms of coordinated imidazole rings. 26 references, 3 figures

  18. Crystal structures of Pseudomonas syringae pv. tomato DC3000 quinone oxidoreductase and its complex with NADPH

    International Nuclear Information System (INIS)

    Zeta-crystallin-like quinone oxidoreductase is NAD(P)H-dependent and catalyzes one-electron reduction of certain quinones to generate semiquinone. Here we present the crystal structures of zeta-crystallin-like quinone oxidoreductase from Pseudomonas syringae pv. tomato DC3000 (PtoQOR) and its complexes with NADPH determined at 2.4 and 2.01 A resolutions, respectively. PtoQOR forms as a homologous dimer, each monomer containing two domains. In the structure of the PtoQOR-NADPH complex, NADPH locates in the groove between the two domains. NADPH binding causes obvious conformational changes in the structure of PtoQOR. The putative substrate-binding site of PtoQOR is wider than that of Escherichia coli and Thermus thermophilus HB8. Activity assays show that PtoQOR has weak 1,4-benzoquinone catalytic activity, and very strong reduction activity towards large substrates such as 9,10-phenanthrenequinone. We propose a model to explain the conformational changes which take place during reduction reactions catalyzed by PtoQOR.

  19. Sensory profile development of Oaxaca cheese and relationship with physicochemical parameters.

    Science.gov (United States)

    Sandoval-Copado, J; Orozco-Villafuerte, J; Pedrero-Fuehrer, D; Colín-Cruz, M A

    2016-09-01

    A sensory profile of Oaxaca cheese was developed. To represent both industrial and artisanal Oaxaca cheese, 3 types of cheese were manufactured under controlled conditions: 2 with pasteurized milk using a mesophilic lactic acid bacteria culture (Lactococcus lactis ssp. lactis and L. lactis ssp. cremoris) and a thermophilic lactic acid bacteria culture (Streptococcus salivarius ssp. thermophilus), and a third with naturally acidified raw milk. The cheeses were evaluated by a panel of 11 trained judges. Additionally, chemical composition and instrumental color parameters were determined, an instrumental texture profile analysis was performed, and volatile compounds were identified by solid-phase microextraction coupled with gas chromatography/mass spectrometry. The sensory profile developed includes 43 descriptors, of which 13 are discriminant among these 3 cheese types. Descriptors include visual attribute waxy; tactile (manual) attributes moist and oily; orthonasal aroma attributes empyreumatic and cow; basic taste attribute salty; mouth texture attributes chewable, gummy, adherent, fibrous, moist, and fatty; and auditory attribute squeaky. A strong correlation was found between specific sensory data and physicochemical parameters measured by instrumental and chemical methods. PMID:27394949

  20. Analysis of microbial diversity on deli slicers using polymerase chain reaction and denaturing gradient gel electrophoresis technologies.

    Science.gov (United States)

    Koo, O K; Mertz, A W; Akins, E L; Sirsat, S A; Neal, J A; Morawicki, R; Crandall, P G; Ricke, S C

    2013-02-01

    Cross-contamination of pathogenic and spoilage bacteria from food-contact surfaces to food products is a serious public health issue. Bacteria may survive and attach to food-contact surfaces by residual food components and/or background bacteria which may subsequently transfer to other food products. Deli slicers, generally used for slicing ready-to-eat products, can serve as potential sources for considerable bacterial transfer. The objective of this study was to assess the extent and distribution of microbial diversity of deli slicers by identification of pathogenic and background bacteria. Slicer-swab samples were collected from restaurants in Arkansas and Texas in the United States. Ten surface areas for each slicer were swabbed using sterile sponges. Denaturing gradient gel electrophoresis (DGGE) was applied to investigate the fingerprint of samples, and each band was further identified by sequence analysis. Pseudomonads were identified as the dominant bacteria followed by Enterobacteriaceae family, and lactic acid bacteria such as Lactococcus lactis and Streptococcus thermophilus were also found. Bacterial distribution was similar for all surface areas, while the blade guard exhibited the greatest diversity. This study provides a profile of the microbial ecology of slicers using DGGE to develop more specific sanitation practices and to reduce cross-contamination during slicing. PMID:23121623

  1. Bioconversion of D-glucose to D-psicose with immobilized D-xylose isomerase and D-psicose 3-epimerase on Saccharomyces cerevisiae spores.

    Science.gov (United States)

    Li, Zijie; Li, Yi; Duan, Shenglin; Liu, Jia; Yuan, Peng; Nakanishi, Hideki; Gao, Xiao-Dong

    2015-08-01

    Saccharomyces cerevisiae spores are dormant cells, which can tolerate various types of environmental stress. In our previous work, we successfully developed biological and chemical methods for enzyme immobilization based on the structures of S. cerevisiae spore wall. In this study, we employed biological and chemical approaches for the immobilization of D-xylose isomerase (XI) from Thermus thermophilus and D-psicose 3-epimerase (DPEase) from Agrobacterium tumefaciens with yeast spores, respectively. The enzymatic properties of both immobilized XI and DPEase were characterized and the immobilized enzymes exhibit higher thermostability, broader pH tolerance, and good repeatability compared with free enzymes. Furthermore, we established a two-step approach for the bioconversion of D-glucose to D-psicose using immobilized enzymes. To improve the conversion yield, a multi-pot strategy was adopted for D-psicose production by repeating the two-step process continually. As a result, the yield of D-psicose was obviously improved and the highest yield reached about 12.0 %. PMID:26065389

  2. Fatty acid profile, trans-octadecenoic, α-linolenic and conjugated linoleic acid contents differing in certified organic and conventional probiotic fermented milks.

    Science.gov (United States)

    Florence, Ana Carolina R; Béal, Catherine; Silva, Roberta C; Bogsan, Cristina S B; Pilleggi, Ana Lucia O S; Gioielli, Luiz Antonio; Oliveira, Maricê N

    2012-12-15

    Development of dairy organic probiotic fermented products is of great interest as they associate ecological practices and benefits of probiotic bacteria. As organic management practices of cow milk production allow modification of the fatty acid composition of milk (as compared to conventional milk), we studied the influence of the type of milk on some characteristics of fermented milks, such as acidification kinetics, bacterial counts and fatty acid content. Conventional and organic probiotic fermented milks were produced using Bifidobacterium animalis subsp. lactis HN019 in co-culture with Streptococcus thermophilus TA040 and Lactobacillus delbrueckii subsp. bulgaricus LB340. The use of organic milk led to a higher acidification rate and cultivability of Lactobacillus bulgaricus. Fatty acids profile of organic fermented milks showed higher amounts of trans-octadecenoic acid (C18:1, 1.6 times) and polyunsaturated fatty acids, including cis-9 trans-11, C18:2 conjugated linoleic (CLA-1.4 times), and α-linolenic acids (ALA-1.6 times), as compared to conventional fermented milks. These higher levels were the result of both initial percentage in the milk and increase during acidification, with no further modification during storage. Finally, use of bifidobacteria slightly increased CLA relative content in the conventional fermented milks, after 7 days of storage at 4°C, whereas no difference was seen in organic fermented milks. PMID:22980792

  3. Lactobacillus fermentum BR11, a potential new probiotic, alleviates symptoms of colitis induced by dextran sulfate sodium (DSS) in rats.

    Science.gov (United States)

    Geier, Mark S; Butler, Ross N; Giffard, Philip M; Howarth, Gordon S

    2007-03-20

    Current treatments for inflammatory bowel disease (IBD) are relatively ineffective. Recently, probiotics have emerged as a potential treatment modality for numerous gastrointestinal disorders, including IBD. Few probiotics, however, have undergone appropriate preclinical screening in vivo. The current study compared the effects of four candidate probiotics on development of dextran sulfate sodium (DSS)-induced colitis in rats. Sprague Dawley rats were gavaged 1 mL of the potential probiotic (1 x 10(10) CFU/mL), or vehicle, twice daily for 14 days. Strains tested were Lactobacillus rhamnosus GG (LGG), Streptococcus thermophilus TH-4 (TH-4), Bifidobacterium lactis Bb12 (Bb12) and Lactobacillus fermentum BR11 (BR11). Colitis was induced from day 7 to 14 via administration of 2% DSS in drinking water. Disease activity index (DAI) was monitored daily until rats were killed at day 14. DAI decreased in DSS+Bb12 and DSS+BR11 compared to DSS+Vehicle. Colon length increased in DSS+BR11 (10%) and DSS+LGG (10%) compared to DSS+Vehicle. DSS+Bb12 and DSS+BR11 prevented the distal colon crypt hyperplasia evident in DSS+Vehicle, DSS+LGG and DSS+TH-4. BR11 was most effective at reducing colitic symptoms. Bb12 had minimal effects, whilst TH-4 did not prevent DSS-colitis and LGG actually exacerbated some indicators of colitis. Further studies into the potential benefits of L. fermentum BR11 are indicated. PMID:17150273

  4. Ingestion of yogurt containing Lactobacillus acidophilus and Bifidobacterium to potentiate immunoglobulin A responses to cholera toxin in mice.

    Science.gov (United States)

    Tejada-Simon, M V; Lee, J H; Ustunol, Z; Pestka, J J

    1999-04-01

    Lactic acid bacteria have been reported to have benefits for the prevention and treatment of some forms of diarrhea and related conditions. To determine whether these effects might involve direct stimulation of the gastrointestinal immune response, we administered yogurt to try to enhance mucosal and systemic antibodies against an orally presented immunogen, cholera toxin. Yogurts were manufactured with starter cultures containing different species and strains of lactic acid bacteria. Mice were fed these yogurts for 3 wk, during which they were also orally immunized twice with 10 micrograms of cholera toxin. Blood was collected on d 0 and 21, and fecal pellets were collected weekly. Mice that were immunized orally with cholera toxin responded by producing specific intestinal and serum immunoglobulin (Ig)A anti-cholera toxin. Antibody responses of the IgA isotype were significantly increased in mice fed yogurts made with starters containing the conventional yogurt bacteria Lactobacillus bulgaricus and Streptococcus thermophilus supplemented with Lactobacillus acidophilus, Bifidobacterium bifidum, and Bifidobacterium infantis. Yogurt that was manufactured with starters containing only conventional yogurt bacteria produced less IgA anti-cholera toxin than did the control group fed nonfat dry milk. Although strong responses were also observed for IgG anti-cholera toxin in serum, the responses did not differ among groups. Thus, administration of yogurt supplemented with L. acidophilus and Bifidobacterium spp. enhanced mucosal and systemic IgA responses to the cholera toxin immunogen. PMID:10212452

  5. Probiotics down-regulate flaA sigma28 promoter in Campylobacter jejuni.

    Science.gov (United States)

    Ding, Wu; Wang, Haifeng; Griffiths, Mansel W

    2005-11-01

    Lactobacilli and bifidobacteria are important members of the gastrointestinal microflora of humans and animals and are thought to have positive effects on human health. Therefore, there is an increasing interest in using these microorganisms as probiotics to be incorporated into either fermented dairy products or tablets. However, convincing scientific data that support claims of their health benefits are scarce. The effect of cell-free extracts of milk fermented by 10 probiotic bacteria (five Bifidobacterium strains and five Lactobacillus strains) on the expression of the flaA gene of Campylobacter jejuni was assessed using a fusion between the flaA sigma28 promoter and a promoterless luxCDABE cassette carried on the plasmid pRYluxCDABE, which resulted in strains with quantifiable luminescence linked to flaA sigma28 promoter activity. Cell-free extracts of milk fermented by all of the tested probiotic strains inhibited the growth of the C. jejuni and down-regulatedflaA sigma28 promoter activity. Two nonprobiotic lactic acid bacterial strains, Lactococcus lactis and Streptococcus thermophilus, were less inhibitory. PMID:16300065

  6. Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment.

    Science.gov (United States)

    Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta; Ercolini, Danilo

    2015-11-01

    Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality. PMID:26341209

  7. [Use of Phaseolus vulgaris and Vigna sinensis in a fermented dairy drink].

    Science.gov (United States)

    Granito, Marisela; Trujillo, Lesma; Guerra, Marisa

    2004-06-01

    The objective of this work was to develop a new kind fermented dairy drink, partially substituted with clear varieties of Phaseolus vulgaris (caraota) and Vigna sinensis (frijol). The formulation of fermented dairy drinks included sterile extracts of caraota and frijol, as partial substitutes which replaced milk: 10, 20 and 30%. The mixtures were inoculated with 2% of a mixture of Lactobacillus acidophillus, Streptococcus thermophilus and Bifidobacterium sp. and were incubated at 42 degrees C for 7 hours. Mango and guava jams were used as flavorings at 20%. On the basis of the sensorial evaluation the mixtures 10% frijol-mango, 10% frijol-guava, 30% caraota-mango and 20% caraota-guava were selected. In the selected fermented dairy drinks, the levels of protein, soluble and insoluble fiber, available and resistant starches were increased and the protein digestibility was 81%. The technical feasibility of partial substitution of milk with extracts of Phaseolus vulgaris or Vigna sinensis. For the elaboration of a fermented dairy drink similar to the liquid yogurt kind was demonstrated. PMID:15586693

  8. Safety Study of Several Common Probiotics in Dairy Products%几种常用乳制品益生菌的安全性研究

    Institute of Scientific and Technical Information of China (English)

    卢静; 黄国任; 沈雪; 于丽萍; 关爽

    2011-01-01

    目的 考察保加利亚杆菌、嗜热链球菌、嗜酸乳杆菌等几种常用乳制品益生菌对Caco-2细胞(结肠癌细胞)增殖的影响及其联合毒性.方法 活化并培养保加利亚杆菌、嗜热链球菌和嗜酸乳杆菌,分别以不同浓度的益生菌处理培养好的Caco-2细胞,用MTT比色法测定益生菌对Caco-2细胞增殖的影响,并确定3种益生菌的半数抑制浓度(IC50).将处于同一浓度级别的3种益生菌等比混合,进行联合毒性实验,用MTT法观察它们的联合毒性作用.结果 3种益生菌在低浓度(102、103、104CFU/ml)未显示出细胞毒性,高浓度(105、06、107、l08、109 CFI/ml)显示出显著的细胞毒性作用,细胞毒性作用随着浓度增加而增强,3种益生菌的IC50分别为:保加利亚杆菌IC50=1.90×lO8,嗜热链球菌IC50=1.86×109,嗜酸乳杆菌IC50=1.81×109.3种益生菌对Caco-2细胞的联合毒性作用与单一益生菌的细胞毒性作用差异无统计学意义(P>0.05),经计算为独立作用.结论 保加利亚杆菌、嗜热链球菌和嗜酸乳杆菌对Caco-2细胞有细胞毒性作用,且呈剂量依赖性,但3种益生菌对Caco-2细胞没有联合毒性作用.%[Objective]To investigate the cytotoxicity and combined toxicity of several common probiotics in dairy products ( Bulgarian bacillus, Streptococcus thermophilus, Lactobacillus acidophilus )on Caco-2 cells (colon cancer ).[Methods]Activating and culturing of Bulgaria bacillus, Streptococcus thermophilus and Lactobacillus acidophilus, then were cultured with Caco-2 cells.The effect and half inhibitory concentration ( IC50 ) of probiotics on Caco-2 cell proliferation was identified by MTT colorimetric assay.The 3 probiotics were equally mixed in the same concentration level.The combined toxicity was examined by MIT assay.[Results]The 3 probiotics did not show cytotoxicity at low concentrations ( 10.2, 10.3, 10.4 CFU/ml), but showed significant cytotoxicity at high concentrations ( 10.5, 10.6, 10

  9. The effect of high pressures on the yoghurt from milk with the stabilizer

    International Nuclear Information System (INIS)

    The effect of high pressures on the microbiological and physio-chemical properties of yoghurt was investigated. The best results were obtained when the yoghurt was manufactured from milk with the addition of MYO 752 stabilizer (starch, gelatin, pectin) selected from 10 stabilizers. Yoghurt manufactured with the addition of 0, 6% MYO 752 stabilizer was processed at the pressure of 400-600 MPa/15 min. in the range of 50 MPa. Pressurization caused a total reduction of number of Lactobacillus delbrueckii ssp. Bulgaricus and reduced the number of Streptococcus thermophilus by 1-2 orders of magnitude. Pressurized and non-pressurized yoghurts characterized of a homogenous consistency and typical plain yoghurt taste. The decrease of the number of living bacteria was observed in yoghurts during the storage. The acidity of pressurized yoghurts remained on the some level at the temperature of 40C and 200C. The more intensive antibacterial activity of microflora was observed in yoghurts storaged at 200C in comparison with yoghurts storaged at 40C. Disadvantageous changes of the pressurized yoghurts consistency were not found. The taste and aroma of yoghurts remained without any changes

  10. Acid production and conversion of konjac glucomannan during in vitro colonic fermentation affected by exogenous microorganisms and tea polyphenols.

    Science.gov (United States)

    Zhao, Xin-Huai; Geng, Qian

    2016-05-01

    Impacts of exogenous microorganisms and tea polyphenols on acid production and conversion during in vitro colonic fermentation of konjac glucomannan (KGM) were assessed in this study. Colonic fermentation of KGM by the fecal extract of healthy adults resulted in a propionate-rich profile, as acetic, propionic, butyric and lactic acids production were 16.1, 13.0, 3.3 and 20.2 mmol/L, respectively. Inoculation of one of ten exogenous microorganisms in the fermentative systems increased acetic, propionic and butyric acids production by 50-230%, 9-190% and 110-350%, respectively, and also accelerated lactic acid conversion by 14-40%. Tea polyphenols in the fermentative systems showed clear inhibition on both acid production and conversion; however, this inhibition could be partially or mostly antagonised by the inoculated exogenous microorganisms, resulting in improved acid production and conversion. In total, Lactobacillus brevis and Sterptococcus thermophilus were more able to increase acid production, and the propionate-rich profile was not changed in all cases. PMID:26902110

  11. Inactivation of the DNA repair genes mutS, mutL or the anti-recombination gene mutS2 leads to activation of vitamin B1 biosynthesis genes.

    Directory of Open Access Journals (Sweden)

    Kenji Fukui

    Full Text Available Oxidative stress generates harmful reactive oxygen species (ROS that attack biomolecules including DNA. In living cells, there are several mechanisms for detoxifying ROS and repairing oxidatively-damaged DNA. In this study, transcriptomic analyses clarified that disruption of DNA repair genes mutS and mutL, or the anti-recombination gene mutS2, in Thermus thermophilus HB8, induces the biosynthesis pathway for vitamin B(1, which can serve as an ROS scavenger. In addition, disruption of mutS, mutL, or mutS2 resulted in an increased rate of oxidative stress-induced mutagenesis. Co-immunoprecipitation and pull-down experiments revealed previously-unknown interactions of MutS2 with MutS and MutL, indicating that these proteins cooperatively participate in the repair of oxidatively damaged DNA. These results suggested that bacterial cells sense the accumulation of oxidative DNA damage or absence of DNA repair activity, and signal the information to the transcriptional regulation machinery for an ROS-detoxifying system.

  12. Crystal structures of Pseudomonas syringae pv. tomato DC3000 quinone oxidoreductase and its complex with NADPH

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xiaowei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Hongmei; Gao, Yu; Li, Mei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China); Chang, Wenrui, E-mail: wrchang@sun5.ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)

    2009-12-18

    Zeta-crystallin-like quinone oxidoreductase is NAD(P)H-dependent and catalyzes one-electron reduction of certain quinones to generate semiquinone. Here we present the crystal structures of zeta-crystallin-like quinone oxidoreductase from Pseudomonas syringae pv. tomato DC3000 (PtoQOR) and its complexes with NADPH determined at 2.4 and 2.01 A resolutions, respectively. PtoQOR forms as a homologous dimer, each monomer containing two domains. In the structure of the PtoQOR-NADPH complex, NADPH locates in the groove between the two domains. NADPH binding causes obvious conformational changes in the structure of PtoQOR. The putative substrate-binding site of PtoQOR is wider than that of Escherichia coli and Thermus thermophilus HB8. Activity assays show that PtoQOR has weak 1,4-benzoquinone catalytic activity, and very strong reduction activity towards large substrates such as 9,10-phenanthrenequinone. We propose a model to explain the conformational changes which take place during reduction reactions catalyzed by PtoQOR.

  13. Antibiotic Resistance of Probiotic Strains of Lactic Acid Bacteria Isolated from Marketed Foods and Drugs

    Institute of Scientific and Technical Information of China (English)

    CHANG LIU; ZHUO-YANG ZHANG; KE DONG; JIAN-PING YUAN; XIAO-KUI GUO

    2009-01-01

    Objective To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probioties. Methods Antimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR. Results Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis. Conclusion Antibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.

  14. Physico-chemical, sensory and microbiological characteristics of plain yoghurt from bambara groundnut (Vigna subterranea) and soybeans (Glycine max).

    Science.gov (United States)

    Falade, Kolawole O; Ogundele, Opeolu M; Ogunshe, Adenike O; Fayemi, Olanrewaju E; Ocloo, Fidelis C K

    2015-09-01

    Physico-chemical, sensory and microbiological characteristics of plain yoghurt from bambara groundnut and soybean milks were studied. Milks were prepared from bambara and soybean and then fermented using Lactobacillus delbruieckii subspp. bulgaricus and Streptococcus salivarus subspp. thermophilus to produce yoghurt. The yoghurts were stored at 7 °C and 27 °C for 9 days and their quality monitored. Results showed that pH of soy and bambara yoghurts decreased during the storage period for both storage temperatures. This decrease in pH was accompanied by simultaneous increase in titratable acidity. Total solids and apparent viscosities of soy and bambara yoghurts increased at 7 °C, but decreased at 27 °C during storage period. Bambara yoghurt received higher sensory acceptability than soy yoghurt. Predominant microorganisms in the stored yoghurts were lactic acid bacteria (LAB). The LAB count in the yoghurts stored at 7 °C decreased but increased at 27 °C during the storage period. Similar trends were followed by total aerobic bacteria, yeast and moulds counts. Pathogenic bacteria such as Salmonella, Coliform and E. coli were absent in all the yogurt samples. Yoghurts of acceptable quality and safety were produced from bambara groundnut and soybeans. PMID:26345001

  15. Functional Screening of Antibiotic Resistance Genes from a Representative Metagenomic Library of Food Fermenting Microbiota

    Directory of Open Access Journals (Sweden)

    Chiara Devirgiliis

    2014-01-01

    Full Text Available Lactic acid bacteria (LAB represent the predominant microbiota in fermented foods. Foodborne LAB have received increasing attention as potential reservoir of antibiotic resistance (AR determinants, which may be horizontally transferred to opportunistic pathogens. We have previously reported isolation of AR LAB from the raw ingredients of a fermented cheese, while AR genes could be detected in the final, marketed product only by PCR amplification, thus pointing at the need for more sensitive microbial isolation techniques. We turned therefore to construction of a metagenomic library containing microbial DNA extracted directly from the food matrix. To maximize yield and purity and to ensure that genomic complexity of the library was representative of the original bacterial population, we defined a suitable protocol for total DNA extraction from cheese which can also be applied to other lipid-rich foods. Functional library screening on different antibiotics allowed recovery of ampicillin and kanamycin resistant clones originating from Streptococcus salivarius subsp. thermophilus and Lactobacillus helveticus genomes. We report molecular characterization of the cloned inserts, which were fully sequenced and shown to confer AR phenotype to recipient bacteria. We also show that metagenomics can be applied to food microbiota to identify underrepresented species carrying specific genes of interest.

  16. Role of the semi-conserved histidine residue in the light-sensing domain of LitR, a MerR-type photosensory transcriptional regulator.

    Science.gov (United States)

    Takano, Hideaki; Mise, Kou; Maruyama, Takafumi; Hagiwara, Kenta; Ueda, Kenji

    2016-08-01

    The LitR/CarH protein family transcriptional regulator is a new type of photoreceptor based on the function of adenosyl B12 (AdoB12) as a light-sensitive ligand. Here, we studied a semi-conserved histidine residue (His132) in the light-sensing (AdoB12-binding) domain at the C-terminus of LitR from a thermophilic Gram-negative bacterium, Thermus thermophilus HB27. The in vivo mutation of His132 within LitR caused a reduction in the rate of carotenoid production in response to illumination. BIAcore analysis revealed that the illuminated-LitRH132A possesses high DNA-binding activity compared to the wild-type protein. The subunit structure analysis showed that LitRH132A performed an incomplete subunit dissociation. The ability of LitRH132A to associate with AdoB12 was reduced compared with that of the wild-type protein in an equilibration dialysis experiment. Overall, these results suggest that His132 of LitR is involved in the association with AdoB12 as well as the light-sensitive DNA-binding activity based on oligomer dissociation. PMID:27283316

  17. X-ray Crystallographic Structure of Thermophilic Rhodopsin: IMPLICATIONS FOR HIGH THERMAL STABILITY AND OPTOGENETIC FUNCTION.

    Science.gov (United States)

    Tsukamoto, Takashi; Mizutani, Kenji; Hasegawa, Taisuke; Takahashi, Megumi; Honda, Naoya; Hashimoto, Naoki; Shimono, Kazumi; Yamashita, Keitaro; Yamamoto, Masaki; Miyauchi, Seiji; Takagi, Shin; Hayashi, Shigehiko; Murata, Takeshi; Sudo, Yuki

    2016-06-01

    Thermophilic rhodopsin (TR) is a photoreceptor protein with an extremely high thermal stability and the first characterized light-driven electrogenic proton pump derived from the extreme thermophile Thermus thermophilus JL-18. In this study, we confirmed its high thermal stability compared with other microbial rhodopsins and also report the potential availability of TR for optogenetics as a light-induced neural silencer. The x-ray crystal structure of TR revealed that its overall structure is quite similar to that of xanthorhodopsin, including the presence of a putative binding site for a carotenoid antenna; but several distinct structural characteristics of TR, including a decreased surface charge and a larger number of hydrophobic residues and aromatic-aromatic interactions, were also clarified. Based on the crystal structure, the structural changes of TR upon thermal stimulation were investigated by molecular dynamics simulations. The simulations revealed the presence of a thermally induced structural substate in which an increase of hydrophobic interactions in the extracellular domain, the movement of extracellular domains, the formation of a hydrogen bond, and the tilting of transmembrane helices were observed. From the computational and mutational analysis, we propose that an extracellular LPGG motif between helices F and G plays an important role in the thermal stability, acting as a "thermal sensor." These findings will be valuable for understanding retinal proteins with regard to high protein stability and high optogenetic performance. PMID:27129243

  18. Monitoring of the microbial communities involved in the soy sauce manufacturing process by PCR-denaturing gradient gel electrophoresis.

    Science.gov (United States)

    Tanaka, Yasushi; Watanabe, Jun; Mogi, Yoshinobu

    2012-08-01

    Soy sauce is a traditional seasoning produced through the fermentation of soybeans and wheat using microbes. In this study, the microbial communities involved in the soy sauce manufacturing process were analyzed by PCR-Denaturing Gradient Gel Electrophoresis (PCR-DGGE). The bacterial DGGE profile indicated that the bacterial microbes in the koji were Weissella cibaria (Weissella confusa, Weissella kimchii, Weissella salipiscis, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus iners, or Streptococcus thermophilus), Staphylococcus gallinarum (or Staphylococcus xylosus), and Staphylococcus kloosii. In addition to these bacteria, Tetragenococcus halophilus was also detected in the mash during lactic acid fermentation. The fungal DGGE profile indicated that the fungal microbes in the koji were not only Aspergillus oryzae but also several yeasts. In the mash, Zygosaccharomyces rouxii appeared in the early fermentation stage, Candida etchellsii (or Candida nodaensis) and Candida versatilis were detected at the middle fermentation stage, and Candida etchellsii was detected at the mature fermentation stage. These results suggest that the microbial communities present during the soy sauce manufacturing process change drastically throughout its production. This is the first report to reveal the microbial communities involved in the soy sauce manufacturing process using a culture-independent method. PMID:22475947

  19. Yoghurt from short supply chain: preliminary study of microbiological and physicochemical characteristics during shelf life

    Directory of Open Access Journals (Sweden)

    Gilberto Giangolini

    2013-04-01

    Full Text Available Yoghurt is one of very popular flavorful and healthful dairy product obtained by fermentation of lactic acid bacteria including Lactobacillus delbrueckii bulgaricus and Streptococcus thermophilus. Its production and consumption is growing continuously due to its therapeutic properties beside its high nutritive value. Thirty samples of yoghurt from short supply chain produced in 2 factory localized in Lazio region were analyzed with the aim of determining how certain microbiological and physicochemical characteristics change during their shelf life. Different types of yoghurt were studied: plain (12, fruit (14 and cereal yoghurt (4 produced with cow (8 and goat milk (22.The obtained results show: no presence of Enterobacteria, occasional presence of moulds and a considerable presence of yeasts. On the other hand, all the products analyzed have shown an almost constant amount of lactic acid bacteria during their shelf life. Lactic acid bacteria were identified by a biochemical and polymerase chain reaction assay. The presence of undesired microorganisms like yeasts was found. However, the quality of products was satisfying for the concentration of lactic acid bacteria detected in their shelf life.

  20. Structural Aspects of Phenylalanylation and Quality Control in Three Major Forms of Phenylalanyl-tRNA Synthetase

    Directory of Open Access Journals (Sweden)

    Liron Klipcan

    2010-01-01

    Full Text Available Aminoacyl-tRNA synthetases (aaRSs are a canonical set of enzymes that specifically attach corresponding amino acids to their cognate transfer RNAs in the cytoplasm, mitochondria, and nucleus. The aaRSs display great differences in primary sequence, subunit size, and quaternary structure. Existence of three types of phenylalanyl-tRNA synthetase (PheRS—bacterial (αβ2, eukaryotic/archaeal cytosolic (αβ2, and mitochondrial α—is a prominent example of structural diversity within the aaRSs family. Although archaeal/eukaryotic and bacterial PheRSs share common topology of the core domains and the B3/B4 interface, where editing activity of heterotetrameric PheRSs is localized, the detailed investigation of the three-dimensional structures from three kingdoms revealed significant variations in the local design of their synthetic and editing sites. Moreover, as might be expected from structural data eubacterial, Thermus thermophilus and human cytoplasmic PheRSs acquire different patterns of tRNAPhe anticodon recognition.

  1. Effect of the vitamin B12-binding protein haptocorrin present in human milk on a panel of commensal and pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Nexø Ebba

    2011-06-01

    Full Text Available Abstract Background Haptocorrin is a vitamin B12-binding protein present in high amounts in different body fluids including human milk. Haptocorrin has previously been shown to inhibit the growth of specific E. coli strains, and the aim of the present study was to elucidate whether the antibacterial properties of this protein may exert a general defense against pathogens and/or affect the composition of the developing microbiota in the gastrointestinal tracts of breastfed infants. Findings The present work was the first systematic study of the effect of haptocorrin on bacterial growth, and included 34 commensal and pathogenic bacteria to which infants are likely to be exposed. Well-diffusion assays addressing antibacterial effects were performed with human milk, haptocorrin-free human milk, porcine holo-haptocorrin (saturated with B-12 and human apo-haptocorrin (unsaturated. Human milk inhibited the growth of S. thermophilus and the pathogenic strains L. monocytogenes LO28, L. monocytogenes 4446 and L. monocytogenes 7291, but the inhibition could not be ascribed to haptocorrin. Human apo-haptocorrin inhibited the growth of only a single bacterial strain (Bifidobacterium breve, while porcine holo-haptocorrin did not show any inhibitory effect. Conclusions Our results suggest that haptocorrin does not have a general antibacterial activity, and thereby contradict the existing hypothesis implicating such an effect. The study contributes to the knowledge on the potential impact of breastfeeding on the establishment of a healthy microbiota in infants.

  2. Structure of the protein core of translation initiation factor 2 in apo, GTP-bound and GDP-bound forms

    Energy Technology Data Exchange (ETDEWEB)

    Simonetti, Angelita [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale - INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France); Marzi, Stefano [Architecture et Réactivité de l’ARN, UPR 9002 CNRS, IBMC (Institute of Molecular and Cellular Biology), 15 Rue R. Descartes, 67084 Strasbourg, France, Université de Strasbourg, 67000 Strasbourg (France); Fabbretti, Attilio [University of Camerino, 62032 Camerino (Monaco) (Italy); Hazemann, Isabelle; Jenner, Lasse [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale -INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France); Urzhumtsev, Alexandre [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale - INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France); Université de Lorraine, 54506 Vandoeuvre-lès-Nancy (France); Gualerzi, Claudio O. [University of Camerino, 62032 Camerino (Monaco) (Italy); Klaholz, Bruno P., E-mail: klaholz@igbmc.fr [IGBMC (Institute of Genetics and of Molecular and Cellular Biology), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé de la Recherche Médicale - INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, 67404 Illkirch (France)

    2013-06-01

    The crystal structures of the eubacterial translation initiation factor 2 in apo form and with bound GDP and GTP reveal conformational changes upon nucleotide binding and hydrolysis, notably of the catalytically important histidine in the switch II region. Translation initiation factor 2 (IF2) is involved in the early steps of bacterial protein synthesis. It promotes the stabilization of the initiator tRNA on the 30S initiation complex (IC) and triggers GTP hydrolysis upon ribosomal subunit joining. While the structure of an archaeal homologue (a/eIF5B) is known, there are significant sequence and functional differences in eubacterial IF2, while the trimeric eukaryotic IF2 is completely unrelated. Here, the crystal structure of the apo IF2 protein core from Thermus thermophilus has been determined by MAD phasing and the structures of GTP and GDP complexes were also obtained. The IF2–GTP complex was trapped by soaking with GTP in the cryoprotectant. The structures revealed conformational changes of the protein upon nucleotide binding, in particular in the P-loop region, which extend to the functionally relevant switch II region. The latter carries a catalytically important and conserved histidine residue which is observed in different conformations in the GTP and GDP complexes. Overall, this work provides the first crystal structure of a eubacterial IF2 and suggests that activation of GTP hydrolysis may occur by a conformational repositioning of the histidine residue.

  3. METABOLIC AND BIOCHEMICAL CHARACTERISTICS OF PROBIOTIC CULTURE IN MILK SUPPLEMENTED WITH RYE FLAKES AND MALT EXTRACT

    Directory of Open Access Journals (Sweden)

    Elena Bărăscu

    2010-01-01

    Full Text Available Rye flakes and malt extract were added to milk in order to stimulate growth and fermentative activity of probioticbacteria and to obtain a probiotic product with pleasant sensory attributes. Probiotic culture used in this study containsbifidobacteria, Lb. acidophilus, Lactobacilus lactis and Streptococcus thermophilus.Rye flakes have a stimulating effect more pronounced than malt extract on acidification capacity of the probioticculture, and to achieve an increase of the milk acidity of 7g lactic acid /dm3 (in 6h at 39oC the two ingredients must beadded in concentration of 2% and, respectively, 0.2%..The probiotic culture reach the greatest proteolytic activity when rye flakes are added in the proportion of 3% andmalt extract in the proportion of 0.1% and the amino acids released rate was 764.6 μg%. The lactose bioconversionrate was greater in the milk supplemented with rye flakes 3% and malt extract 0.1% and residual lactose was 3.84%.

  4. The effect of high pressures on the yoghurt from milk with the stabilizer

    Energy Technology Data Exchange (ETDEWEB)

    Reps, A; Jankowska, A; Wisniewska, K [Chair of Food Biotechnology, University of Warmia and Mazury, Heweliusza str 1., 10-724 Olsztyn (Poland)], E-mail: arnold.reps@uwm.edu.pl

    2008-07-15

    The effect of high pressures on the microbiological and physio-chemical properties of yoghurt was investigated. The best results were obtained when the yoghurt was manufactured from milk with the addition of MYO 752 stabilizer (starch, gelatin, pectin) selected from 10 stabilizers. Yoghurt manufactured with the addition of 0, 6% MYO 752 stabilizer was processed at the pressure of 400-600 MPa/15 min. in the range of 50 MPa. Pressurization caused a total reduction of number of Lactobacillus delbrueckii ssp. Bulgaricus and reduced the number of Streptococcus thermophilus by 1-2 orders of magnitude. Pressurized and non-pressurized yoghurts characterized of a homogenous consistency and typical plain yoghurt taste. The decrease of the number of living bacteria was observed in yoghurts during the storage. The acidity of pressurized yoghurts remained on the some level at the temperature of 4{sup 0}C and 20{sup 0}C. The more intensive antibacterial activity of microflora was observed in yoghurts storaged at 20{sup 0}C in comparison with yoghurts storaged at 4{sup 0}C. Disadvantageous changes of the pressurized yoghurts consistency were not found. The taste and aroma of yoghurts remained without any changes.

  5. Evaluation of anti-bacterial and anti-oxidant potential of andrographolide and echiodinin isolated from callus culture of Andrographis paniculata Nees

    Institute of Scientific and Technical Information of China (English)

    Mohammed Arifullah; Nima Dandu Namsa; Manabendra Mandal; Kishore Kumar Chiruvella; Paritala Vikrama; Ghanta Rama Gopal

    2013-01-01

    Objective: To evaluate the anti-bacterial and anti-oxidant activity of andrographolide (AND) and echiodinin (ECH) of Andrographis paniculata. Methods:In this study, an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-diphenyl-2-picryl-hydrazyl (DPPH) assay, respectively. Structure elucidation was determined by electro-spray ionization-MSD, NMR (1H and 13C) and IR spectra. Results: AND was effective against most of the strains tested including Mycobacteriumsmegmatis, showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values against Staphylococcus aureus (100 µg/mL), Streptococcus thermophilus (350 µg/mL) Bacillus subtilis (100 µg/mL), Escherichia coli (50 µg/mL), Mycobacterium smegmatis (200 µg/mL), Klebsiella pneumonia (100 µg/mL), and Pseudomonas aeruginosa (200 µg/mL). ECH showed specific anti-bacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa at a concentration higher than 225 µg/mL. Both AND and ECH were not effective against the two yeast strains, Candida albicans and Saccharomyces cerevisiae tested in this study. Conclusion:This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH, and it may provide the scientific rationale for its popular folklore medicines.

  6. SENSORY EVALUATION AND SURVIVAL OF PROBIOTICS IN MODIFIED BANANA FLOUR YOGHURT DURING STORAGE [Evaluasi Sensori dan Sintasan Probiotik dalam Yoghurt Tepung Pisang Modifikasi selama Penyimpanan

    Directory of Open Access Journals (Sweden)

    Widaningrum3

    2013-06-01

    Full Text Available Modified uli banana flour (MUBF rich in resistant starch as prebiotic source was formulated in yoghurt making to substitute skim milk at various concentrations i.e. 40, 50, 60, and 70%. Yoghurts were prepared using Lactobacillus bulgaricus and Streptococcus thermophilus as the starter cultures. The objective of this study was to determine the maximum MUBF concentration to produce yoghurt with good sensory quality and good number of surviving probiotics (Bifidobacterium bifidum and Lactobacillus plantarum BSL in non-pasteurized and pasteurized (90ºC, 30 minutes MUBF yoghurt during 4 week of storage at 10ºC. Hedonic rating and ranking test on yoghurt attributes (aroma, taste, consistency, texture, color and overall preference performed by 35 untrained panelists showed that yoghurt produced with 70% MUBF substitution achieved good preferences in all of the attributes ranging from neutral to like. The pH value of the product decreased with increase in MUBF concentration. In addition, titratable acidity (TA, expressed as % lactic acid, increased. Survival of both probiotics in 70% MUBF yoghurt either in the pasteurized synbiotic or non-pasteurized yoghurts were still relatively high at week 4. The yoghurt still contains 108 CFU/ml of lactic acid bacteria, although this was a log decrease from the initial count. Therefore, the MUBF yoghurt was promising as synbiotic yoghurt based on the probiotic counts throughout 4 week of storage, which was higher than the minimum level recommended (106 CFU/ml to provide the beneficial effect.

  7. Characterization of goat milk and potentially symbiotic non-fat yogurt

    Directory of Open Access Journals (Sweden)

    Noelia Fernanda Paz

    2014-09-01

    Full Text Available Combining prebiotics and probiotic microorganisms improve quality in the formulation of foods. In this paper, the characteristics of goat milk and symbiotic yogurt were studied. Raw goat milk was analyzed and the skimming process was optimized. For the formulation of a potentially non-fat symbiotic yogurt made with skimmed goat milk, inulin, gelatin, sugar, and Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. rhamnoshus. Chemical characteristics, acceptability, and viability of lactic acid bacteria and probiotic culture were assessed. The protein and fat content of the raw milk was 2.90 and 3.56 g/100 mL, respectively. The optimum skimming process was obtained at 9,800 rpm and 4 °C for 15 minutes. The product formulated had a protein and fat content of 4.04 to 0.04 g/100 mL, good sensory properties, and acceptability of 95%. The lactic bacteria count was 9 × 10(7 CFU mL- 1, and probiotic culture count was higher than 1 × 10(6 CFU mL- 1, which guarantees their effect and capacity to survive in the digestive tract and spread in the intestine. The yogurt was stable during the 21 days of storage. Therefore, this study shows that goat milk yogurt is an adequate delivery vehicle of the probiotic culture L. casei and inulin.

  8. Effects of selected factors on rheological and textural properties of probiotic yoghurt

    Directory of Open Access Journals (Sweden)

    Jovana Glušac

    2011-03-01

    Full Text Available The aim of this work was to study the influence of inulin (1 %, combination of inulin (1 % and acacia honey (4 %, heat treatment of milk, and storage time on the rheological and textural properties of probiotic yoghurt. Rheological properties were assessed trough viscosity, syneresis and texture (firmness, consistency, cohesiveness and index of viscosity. Yoghurt was prepared from milk (1,5 % fat with added inulin (1% before heat treatment at 85 °C for 20 min or 95 °C for 10 min. After cooling to 55 °C honey (4 % was added. Samples were inoculated using probiotic starter culture (70 % w/w Streptococcus thermophilus, 10 % w/w Lactobacillus bulgaricus, 10 % w/w Lactobacillus acidophilus, 10 % w/w Bifidobacterium ssp.. Yoghurt samples were held on +5 °C during 21 days. Measurements of pH value, lactic acid, viscosity, syneresis, and textural properties were done after 1, 7, 14 and 21 days of storage. The results of this study show that honey addition significantly decreased fermentation time compared to fermentation time of control samples or samples containing inulin. Furthermore, addition of honey and inulin to milk caused significant lower syneresis (p<0,05 during storage time, while there was no significant influence on viscosity and texture of final product. The applied heat treatment of milk had no significant influence on rheological properties of probiotic yoghurt.

  9. Development of a non-dairy probiotic fermented product based on almond milk and inulin.

    Science.gov (United States)

    Bernat, Neus; Cháfer, Maite; Chiralt, Amparo; González-Martínez, Chelo

    2015-09-01

    A new fermented almond "milk" that combined the properties of both almonds and probiotics was considered to cover the current versatile health-promoting foods' demand. Almond milk fermentation with probiotic Lactobacillus reuteri and Streptococcus thermophilus was studied by using a Central Composite design with response surface methodology, and different factors (glucose, fructose, inulin and starters) were optimised to assure high probiotic survivals in the final product. The optimal formulation was physicochemically characterised throughout cold storage (28 days) and both probiotic survivals to in vitro digestion and proteolysis were quantified. Results showed that a high probiotic population (>10(7) cfu/mL) was obtained in the previously optimised almond milk throughout storage time, which correspond to the addition of 0.75 g of glucose/100 mL, 0.75 g of fructose/100 mL, 2 g/100 mL inulin and 6 mL/100 mL inoculum. Glucose was used as the main nutrient and the production of mannitol by L. reuteri was detected. The fermentation process increased the viscosity values, forming a weak gel structure, whose physical properties hardly changed. Probiotic bacteria notably survived (51%) to the in vitro digestion, surely related to the inulin presence, which would add value to the developed product by enhancing the potential health benefits of its consumption. PMID:25028153

  10. Alkalizing reactions streamline cellular metabolism in acidogenic microorganisms.

    Directory of Open Access Journals (Sweden)

    Stefania Arioli

    Full Text Available An understanding of the integrated relationships among the principal cellular functions that govern the bioenergetic reactions of an organism is necessary to determine how cells remain viable and optimise their fitness in the environment. Urease is a complex enzyme that catalyzes the hydrolysis of urea to ammonia and carbonic acid. While the induction of urease activity by several microorganisms has been predominantly considered a stress-response that is initiated to generate a nitrogen source in response to a low environmental pH, here we demonstrate a new role of urease in the optimisation of cellular bioenergetics. We show that urea hydrolysis increases the catabolic efficiency of Streptococcus thermophilus, a lactic acid bacterium that is widely used in the industrial manufacture of dairy products. By modulating the intracellular pH and thereby increasing the activity of β-galactosidase, glycolytic enzymes and lactate dehydrogenase, urease increases the overall change in enthalpy generated by the bioenergetic reactions. A cooperative altruistic behaviour of urease-positive microorganisms on the urease-negative microorganisms within the same environment was also observed. The physiological role of a single enzymatic activity demonstrates a novel and unexpected view of the non-transcriptional regulatory mechanisms that govern the bioenergetics of a bacterial cell, highlighting a new role for cytosol-alkalizing biochemical pathways in acidogenic microorganisms.

  11. Alkalizing Reactions Streamline Cellular Metabolism in Acidogenic Microorganisms

    Science.gov (United States)

    Arioli, Stefania; Ragg, Enzio; Scaglioni, Leonardo; Fessas, Dimitrios; Signorelli, Marco; Karp, Matti; Daffonchio, Daniele; De Noni, Ivano; Mulas, Laura; Oggioni, Marco; Guglielmetti, Simone; Mora, Diego

    2010-01-01

    An understanding of the integrated relationships among the principal cellular functions that govern the bioenergetic reactions of an organism is necessary to determine how cells remain viable and optimise their fitness in the environment. Urease is a complex enzyme that catalyzes the hydrolysis of urea to ammonia and carbonic acid. While the induction of urease activity by several microorganisms has been predominantly considered a stress-response that is initiated to generate a nitrogen source in response to a low environmental pH, here we demonstrate a new role of urease in the optimisation of cellular bioenergetics. We show that urea hydrolysis increases the catabolic efficiency of Streptococcus thermophilus, a lactic acid bacterium that is widely used in the industrial manufacture of dairy products. By modulating the intracellular pH and thereby increasing the activity of β-galactosidase, glycolytic enzymes and lactate dehydrogenase, urease increases the overall change in enthalpy generated by the bioenergetic reactions. A cooperative altruistic behaviour of urease-positive microorganisms on the urease-negative microorganisms within the same environment was also observed. The physiological role of a single enzymatic activity demonstrates a novel and unexpected view of the non-transcriptional regulatory mechanisms that govern the bioenergetics of a bacterial cell, highlighting a new role for cytosol-alkalizing biochemical pathways in acidogenic microorganisms. PMID:21152088

  12. CRISPRTarget: bioinformatic prediction and analysis of crRNA targets.

    Science.gov (United States)

    Biswas, Ambarish; Gagnon, Joshua N; Brouns, Stan J J; Fineran, Peter C; Brown, Chris M

    2013-05-01

    The bacterial and archaeal CRISPR/Cas adaptive immune system targets specific protospacer nucleotide sequences in invading organisms. This requires base pairing between processed CRISPR RNA and the target protospacer. For type I and II CRISPR/Cas systems, protospacer adjacent motifs (PAM) are essential for target recognition, and for type III, mismatches in the flanking sequences are important in the antiviral response. In this study, we examine the properties of each class of CRISPR. We use this information to provide a tool (CRISPRTarget) that predicts the most likely targets of CRISPR RNAs (http://bioanalysis.otago.ac.nz/CRISPRTarget). This can be used to discover targets in newly sequenced genomic or metagenomic data. To test its utility, we discover features and targets of well-characterized Streptococcus thermophilus and Sulfolobus solfataricus type II and III CRISPR/Cas systems. Finally, in Pectobacterium species, we identify new CRISPR targets and propose a model of temperate phage exposure and subsequent inhibition by the type I CRISPR/Cas systems. PMID:23492433

  13. Community dynamics and glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Gladden, J.M.; Allgaier, M.; Miller, C.S.; Hazen, T.C.; VanderGheynst, J.S.; Hugenholtz, P.; Simmons, B.A.; Singer, S.W.

    2011-05-01

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60 C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80 C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  14. Potential use of scotta, the by-product of the ricotta cheese manufacturing process, for the production of fermented drinks.

    Science.gov (United States)

    Maragkoudakis, Petros; Vendramin, Veronica; Bovo, Barbara; Treu, Laura; Corich, Viviana; Giacomini, Alessio

    2016-02-01

    In the present work, the use of scotta as substrate for bacterial fermentation was studied with the objective of obtaining a drink from transformation of this by-product. Scotta retains most of the lactose of the milk and it is normally colonized by a natural microbiota. A treatment was devised to reduce the autochthonous microbial populations in order to reduce competition towards the inoculated bacterial strains. Nine lactic acid bacteria (LAB) were assessed for their capability to develop in scotta. They evidenced different behaviors regarding growth rate, acidification capability and nitrogen consumption. A co-inoculum of three LAB, namely a Streptococcus thermophilus, a Lactobacillus delbrueckii subsp. bulgaricus and a Lb. acidophilus strains, chosen among those giving the best performances in single-strain fermentation trials, gave abundant (close to 10(9) cfu/ml) and balanced growth and lowered pH to 4.2, a value similar to that of yogurt. These results show that scotta may have potential as a substrate for bacterial growth for the production of a fermented drink. Further studies are needed to optimize the organoleptic aspects of the final product. PMID:26608679

  15. Preliminary studies on DNA retardation by MutS applied to the detection of point mutations in clinical samples

    International Nuclear Information System (INIS)

    MutS ability to bind DNA mismatches was applied to the detection of point mutations in PCR products. MutS recognized mismatches from single up to five nucleotides and retarded the electrophoretic migration of mismatched DNA. The electrophoretic detection of insertions/deletions above three nucleotides is also possible without MutS, thanks to the DNA mobility shift caused by the presence of large insertion/deletion loops in the heteroduplex DNA. Thus, the method enables the search for a broad range of mutations: from single up to several nucleotides. The mobility shift assays were carried out in polyacrylamide gels stained with SYBR-Gold. One assay required 50-200 ng of PCR product and 1-3 μg of Thermus thermophilus his6-MutS protein. The advantages of this approach are: the small amounts of DNA required for the examination, simple and fast staining, no demand for PCR product purification, no labelling and radioisotopes required. The method was tested in the detection of cancer predisposing mutations in RET, hMSH2, hMLH1, BRCA1, BRCA2 and NBS1 genes. The approach appears to be promising in screening for unknown point mutations

  16. Identification and quantification of a novel nitrate-reducing community in sediments of Suquia River basin along a nitrate gradient

    International Nuclear Information System (INIS)

    We evaluated the molecular diversity of narG gene from Suquia River sediments to assess the impact of the nitrate concentration and water quality on the composition and structure of the nitrate-reducing bacterial community. To this aim, a library of one of the six monitoring stations corresponding to the highest nitrate concentration was constructed and 118 narG clones were screened. Nucleotide sequences were associated to narG gene from alpha-, beta-, delta-, gammaproteobacteria and Thermus thermophilus. Remarkably, 18% of clones contained narG genes with less than 69% similarity to narG sequences available in databases. Thus, indicating the presence of nitrate-reducing bacteria with novel narG genes, which were quantified by real-time PCR. Results show a variable number of narG copies, ranging from less than 1.0 x 102 to 5.0 x 104 copies per ng of DNA, which were associated with a decreased water quality index monitored along the basin at different times. - A novel narG community present in Suquia River sediments was quantified; values were in line with the water quality index.

  17. Structural studies of EF-Tu complexes

    DEFF Research Database (Denmark)

    Johansen, Jesper Sanderhoff

    2011-01-01

    elongation factor, EF-Ts, catalyse the dissociation of GDP from EF-Tu which in turn allows EF-Tu to bind another GTP molecule. The resulting EF-Tu:GTP complex is then cable of forming a ternary complex with a new aa-tRNA which can then associate with the ribosome. During my time as a Ph. D. student I have...... manuscript I. G. anatolicus is a hyperthermophilic bacteria isolated from a thermal vent. The structure of G. anatolicus EF-Ts has been determined in complex with E. coli EF-Tu by X-ray crystallography to a resolution of 2.8 Å. The structure of G. anatolicus EF-Ts is more similar to the previously determined...... structures of E. coli and bovine mitochondrial EF-Ts rather than EF-Ts from the thermophilic bacteria T. thermophilus. The structure of G. anatolicus EF-Ts in complex with E. coli EF-Tu is presented in chapter 3 and in manuscript II. Mammalian mitochondria contain an independent genome which encodes 13...

  18. Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

    Science.gov (United States)

    Huang, Song; Chen, Xiao Dong

    2013-07-01

    The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. PMID:23617813

  19. Survival and bioactivities of selected probiotic lactobacilli in yogurt fermentation and cold storage: New insights for developing a bi-functional dairy food.

    Science.gov (United States)

    Rutella, Giuseppina Sefora; Tagliazucchi, Davide; Solieri, Lisa

    2016-12-01

    In previous work, we demonstrated that two probiotic strains, namely Lactobacillus casei PRA205 and Lactobacillus rhamnosus PRA331, produce fermented milks with potent angiotensin-converting enzyme (ACE)-inhibitory and antioxidant activities. Here, we tested these strains for the survivability and the release of antihypertensive and antioxidant peptides in yogurt fermentation and cold storage. For these purposes three yogurt batches were compared: one prepared using yogurt starters alone (Lactobacillus delbrueckii subspecies bulgaricus 1932 and Streptococcus thermophilus 99), and the remaining two containing either PRA205 or PRA331 in addition to yogurt starters. Despite the lower viable counts at the fermentation end compared to PRA331, PRA205 overcame PRA331 in survivability during refrigerated storage for 28 days, leading to viable counts (>10(8) CFU/g) higher than the minimum therapeutic threshold (10(6) CFU/g). Analyses of in vitro ACE-inhibitory and antioxidant activities of peptide fractions revealed that yogurt supplemented with PRA205 displays higher amounts of antihypertensive and antioxidant peptides than that produced with PRA331 at the end of fermentation and over storage. Two ACE-inhibitory peptides, Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP), were identified and quantified. This study demonstrated that L. casei PRA205 could be used as adjunct culture for producing bi-functional yogurt enriched in bioactive peptides and in viable cells, which bring health benefits to the host as probiotics. PMID:27554146

  20. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals.

    Science.gov (United States)

    Dao, E Han; Sierra, Raymond G; Laksmono, Hartawan; Lemke, Henrik T; Alonso-Mori, Roberto; Coey, Aaron; Larsen, Kevin; Baxter, Elizabeth L; Cohen, Aina E; Soltis, S Michael; DeMirci, Hasan

    2015-07-01

    In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS) using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecond X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser. PMID:26798805

  1. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals

    Directory of Open Access Journals (Sweden)

    E. Han Dao

    2015-07-01

    Full Text Available In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecond X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser.

  2. Plant extract enhances the viability of Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus acidophilus in probiotic nonfat yogurt.

    Science.gov (United States)

    Michael, Minto; Phebus, Randall K; Schmidt, Karen A

    2015-01-01

    A commercial plant extract (prepared from olive, garlic, onion and citrus extracts with sodium acetate (SA) as a carrier) was evaluated to extend the viability of yogurt starter and probiotic bacteria as a means to enhance the shelf life of live and active culture, probiotic nonfat yogurt. Yogurts prepared from three different formulas (0.5* plant extract, 0.25* SA, or no supplement) and cultures (yogurt starter plus Bifidobacterium animalis,Lactobacillus acidophilus, or both probiotics) were assessed weekly during 29 days of storage at 5°C. Supplemented yogurt mixes had greater buffering capacities than non-supplemented yogurt mixes. At the end of storage, Lactobacillus bulgaricus and L. acidophilus counts in supplemented yogurts were greater compared with non-supplemented yogurts. Supplementation did not affect Streptococcus thermophilus and B. animalis counts. Hence the greater buffering capacity of yogurt containing plant extract could enhance the longevity of the probiotics, L. bulgaricus and L. acidophilus, during storage. PMID:25650127

  3. CRISPR-induced distributed immunity in microbial populations.

    Directory of Open Access Journals (Sweden)

    Lauren M Childs

    Full Text Available In bacteria and archaea, viruses are the primary infectious agents, acting as virulent, often deadly pathogens. A form of adaptive immune defense known as CRISPR-Cas enables microbial cells to acquire immunity to viral pathogens by recognizing specific sequences encoded in viral genomes. The unique biology of this system results in evolutionary dynamics of host and viral diversity that cannot be fully explained by the traditional models used to describe microbe-virus coevolutionary dynamics. Here, we show how the CRISPR-mediated adaptive immune response of hosts to invading viruses facilitates the emergence of an evolutionary mode we call distributed immunity - the coexistence of multiple, equally-fit immune alleles among individuals in a microbial population. We use an eco-evolutionary modeling framework to quantify distributed immunity and demonstrate how it emerges and fluctuates in multi-strain communities of hosts and viruses as a consequence of CRISPR-induced coevolution under conditions of low viral mutation and high relative numbers of viral protospacers. We demonstrate that distributed immunity promotes sustained diversity and stability in host communities and decreased viral population density that can lead to viral extinction. We analyze sequence diversity of experimentally coevolving populations of Streptococcus thermophilus and their viruses where CRISPR-Cas is active, and find the rapid emergence of distributed immunity in the host population, demonstrating the importance of this emergent phenomenon in evolving microbial communities.

  4. Bacteria and yeast microbiota in milk kefir grains from different Italian regions.

    Science.gov (United States)

    Garofalo, Cristiana; Osimani, Andrea; Milanović, Vesna; Aquilanti, Lucia; De Filippis, Francesca; Stellato, Giuseppina; Di Mauro, Simone; Turchetti, Benedetta; Buzzini, Pietro; Ercolini, Danilo; Clementi, Francesca

    2015-08-01

    Kefir grains are a unique symbiotic association of different microrganisms, mainly lactic acid bacteria, yeasts and occasionally acetic acid bacteria, cohabiting in a natural polysaccharide and a protein matrix. The microbial composition of kefir grains can be considered as extremely variable since it is strongly influenced by the geographical origin of the grains and by the sub-culturing method used. The aim of this study was to elucidate the bacteria and yeast species occurring in milk kefir grains collected in some Italian regions by combining the results of scanning electron microscopy analysis, viable counts on selective culture media, PCR-DGGE and pyrosequencing. The main bacterial species found was Lactobacillus kefiranofaciens while Dekkera anomala was the predominant yeast. The presence of sub-dominant species ascribed to Streptococcus thermophilus, Lactococcus lactis and Acetobacter genera was also highlighted. In addition, Lc. lactis, Enterococcus sp., Bacillus sp., Acetobacter fabarum, Acetobacter lovaniensis and Acetobacter orientalis were identified as part of the cultivable community. This work further confirms both the importance of combining culture-independent and culture-dependent approaches to study microbial diversity in food and how the combination of multiple 16S rRNA gene targets strengthens taxonomic identification using sequence-based identification approaches. PMID:25846922

  5. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate-oxidizing bacteria.

    Science.gov (United States)

    Wang, Han; Fotidis, Ioannis A; Angelidaki, Irini

    2015-11-01

    Ammonia-rich substrates can cause inhibition on anaerobic digestion process. Syntrophic acetate-oxidizing bacteria (SAOB) and hydrogenotrophic methanogens are important for the ammonia inhibitory mechanism on anaerobic digestion. The roles and interactions of SAOB and hydrogenotrophic methanogens to ammonia inhibition effect are still unclear. The aim of the current study was to determine the ammonia toxicity levels of various pure strains of SAOB and hydrogenotrophic methanogens. Moreover, ammonia toxicity on the syntrophic-cultivated strains of SAOB and hydrogenotrophic methanogens was tested. Thus, four hydrogenotrophic methanogens (i.e. Methanoculleus bourgensis, Methanobacterium congolense, Methanoculleu thermophilus and Methanothermobacter thermautotrophicus), two SAOB (i.e. Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) and their syntrophic cultivation were assessed under 0.26, 3, 5 and 7 g NH4 (+)-N L(-1). The results showed that some hydrogenotrophic methanogens were equally, or in some cases, more tolerant to high ammonia levels compared to SAOB. Furthermore, a mesophilic hydrogenotrophic methanogen was more sensitive to ammonia toxicity compared to thermophilic methanogens tested in the study, which is contradicting to the general belief that thermophilic methanogens are more vulnerable to high ammonia loads compared to mesophilic. This unexpected finding underlines the fact that the complete knowledge of ammonia inhibition effect on hydrogenotrophic methanogens is still absent. PMID:26490748

  6. Effect of Different Storage Period on Lactic Acid Bacterias from Goji Yogurt and Goji Yogurt with Honey

    Directory of Open Access Journals (Sweden)

    Ancuta M. Rotar

    2014-05-01

    Full Text Available Lactic acid bacterias (LAB: Streptococcus thermophilus-ST, Lactobacillus bulgaricus-LB are well known in the food technology area for their ability to produce lactic acid (LA from carbohydrates throught fermentation. In case of goji yogurt the interaction between the two species of LAB has influence on the fermentation period and LA quantity. LAB’s are widely used in the food industry because their growth in the dairy products lowers the carbohydrate content, they can also drop the pH values under 4.0, values were common pathogens are inhibited, and because of all these properties they are capable to prolong the shelf life. The present study aims to observe the evolution of LAB’s – ST and LB, from goji yogurt (7% (A and goji yogurt (7% with honey (B during the shelf life in corelation with other physico-chemical properties such as sugar content, fat content and dry matter. The samples for the evaluation were taken in the first day of storage, at the middle of storage period and in the last day of storage.

  7. A Bio-computing Analysis of the Resting-to-pulsed Conformational Changes in Cytochrome c Oxidase

    Directory of Open Access Journals (Sweden)

    T Alleyne

    2015-09-01

    Full Text Available Cytochrome c oxidase (Cox accepts electrons from its substrate, cytochrome c and passes these to oxygen, which is reduced to water. Kinetic studies show that an active form of the enzyme (pulsed and a slower form (resting exists. More efficient internal electron transfer and the switching of the enzyme’s oxygen/ligand binding site between opened and closed positions are said to account for the different rates of reduction. We employed bio-computing to analyse the structure of the oxygen/ligand binding site of bovine Cox under different redox states; a comparison with Thermus thermophilus Cox was also conducted. The study detected that the ligand binding site of Cox is exposed to the contents of the intermembrane space, and that the side chain of haem a3, located at the enzyme’s oxygen/ligand binding site, approached Pro-69 and Ile-34 in faraway subunit-II. However, no open-to-closed gating structures were detected at the ligand binding site. We concluded that the resting-to-pulse transition in Cox does not involve opening-up of the ligand binding site. We propose that the rates of ligand/oxygen/cyanide binding are partly controlled by “queuing” near the binding site and that the binding of oxygen to haem a3-CuB triggers the resting-to-pulsed transition via long-range conformational changes.

  8. 2',3'-Cyclic nucleotide 3'-phosphodiesterase: a novel RNA-binding protein that inhibits protein synthesis.

    Science.gov (United States)

    Gravel, Michel; Robert, Francis; Kottis, Vicky; Gallouzi, Imed-Eddine; Pelletier, Jerry; Braun, Peter E

    2009-04-01

    2',3'-Cyclic nucleotide 3'-phosphodiesterase (CNP) is one of the earliest myelin-related proteins to be specifically expressed in differentiating oligodendrocytes (ODCs) in the central nervous system (CNS) and is implicated in myelin biogenesis. CNP possesses an in vitro enzymatic activity, whose in vivo relevance remains to be defined, because substrates with 2',3,-cyclic termini have not yet been identified. To characterize CNP function better, we previously determined the structure of the CNP catalytic domain by NMR. Interestingly, the structure is remarkably similar to the plant cyclic nucleotide phosphodiesterase (CPDase) from A. thaliana and the bacterial 2'-5' RNA ligase from T. thermophilus, which are known to play roles in RNA metabolism. Here we show that CNP is an RNA-binding protein. Furthermore, by using precipitation analyses, we demonstrate that CNP associates with poly(A)(+) mRNAs in vivo and suppresses translation in vitro in a dose-dependent manner. With SELEX, we isolated RNA aptamers that can suppress the inhibitory effect of CNP on translation. We also demonstrate that CNP1 can bridge an association between tubulin and RNA. These results suggest that CNP1 may regulate expression of mRNAs in ODCs of the CNS. PMID:19021295

  9. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts.

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt. PMID:27499669

  10. Structure of Vibrio cholerae ribosome hibernation promoting factor

    International Nuclear Information System (INIS)

    The X-ray crystal structure of ribosome hibernation promoting factor from V. cholerae has been determined at 2.0 Å resolution. The crystal was phased by two-wavelength MAD using cocrystallized cobalt. The X-ray crystal structure of ribosome hibernation promoting factor (HPF) from Vibrio cholerae is presented at 2.0 Å resolution. The crystal was phased by two-wavelength MAD using cocrystallized cobalt. The asymmetric unit contained two molecules of HPF linked by four Co atoms. The metal-binding sites observed in the crystal are probably not related to biological function. The structure of HPF has a typical β–α–β–β–β–α fold consistent with previous structures of YfiA and HPF from Escherichia coli. Comparison of the new structure with that of HPF from E. coli bound to the Thermus thermophilus ribosome [Polikanov et al. (2012 ▶), Science, 336, 915–918] shows that no significant structural changes are induced in HPF by binding

  11. Effect of Aqueous Extract of the Seaweed Gracilaria domingensis on the Physicochemical, Microbiological, and Textural Features of Fermented Milks.

    Science.gov (United States)

    Tavares Estevam, Adriana Carneiro; Alonso Buriti, Flávia Carolina; de Oliveira, Tiago Almeida; Pereira, Elainy Virginia Dos Santos; Florentino, Eliane Rolim; Porto, Ana Lúcia Figueiredo

    2016-04-01

    The effects of the Gracilaria domingensis seaweed aqueous extract in comparison with gelatin on the physicochemical, microbial, and textural characteristics of fermented milks processed with the mixed culture SAB 440 A, composed of Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium animalis ssp. lactis, were investigated. The addition of G. domingensis aqueous extract did not affect pH, titratable acidity, and microbial viability of fermented milks when compared with the control (with no texture modifier) and the products with added gelatin. Fermented milk with added the seaweed aqueous extract showed firmness, consistency, cohesiveness, and viscosity index at least 10% higher than those observed for the control product (P seaweed extract added, a behavior not observed in products with the full amount of gelatin, probably due to the differences between the interactions of these ingredients with casein during the development of the gel network throughout the acidification of milk. The G. domingensis aqueous extract appears as a promising gelatin alternative to be used as texture modifier in fermented milks and related dairy products. PMID:26989840

  12. Proteogenomic Analysis of a Thermophilic Bacterial Consortium Adapted to Deconstruct Switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    D' haeseleer, Patrik; Gladden, John M.; Allgaier, Martin; Chain, Patrick; Tringe, Susannah G.; Malfatti, Stephanie; Aldrich, Joshua T.; Nicora, Carrie D.; Robinson, Errol W.; Pasa-Tolic, Ljiljana; Hugenholtz, Philip; Simmons, Blake A.; Singer, Steven W.

    2013-07-19

    Thermophilic bacteria are a potential source of enzymes for the deconstruction of lignocellulosic biomass. However, the complement of proteins used to deconstruct biomass and the specific roles of different microbial groups in thermophilic biomass deconstruction are not well-explored. Here we report on the metagenomic and proteogenomic analyses of a compost-derived bacterial consortium adapted to switchgrass at elevated temperature with high levels of glycoside hydrolase activities. Near-complete genomes were reconstructed for the most abundant populations, which included composite genomes for populations closely related to sequenced strains of Thermus thermophilus and Rhodothermus marinus, and for novel populations that are related to thermophilic Paenibacilli and an uncultivated subdivision of the littlestudied Gemmatimonadetes phylum. Partial genomes were also reconstructed for a number of lower abundance thermophilic Chloroflexi populations. Identification of genes for lignocellulose processing and metabolic reconstructions suggested Rhodothermus, Paenibacillus and Gemmatimonadetes as key groups for deconstructing biomass, and Thermus as a group that may primarily metabolize low molecular weight compounds. Mass spectrometry-based proteomic analysis of the consortium was used to identify .3000 proteins in fractionated samples from the cultures, and confirmed the importance of Paenibacillus and Gemmatimonadetes to biomass deconstruction. These studies also indicate that there are unexplored proteins with important roles in bacterial lignocellulose deconstruction.

  13. Applicability of a Lactobacillus amylovorus strain as co-culture for natural folate bio-enrichment of fermented milk.

    Science.gov (United States)

    Laiño, Jonathan Emiliano; Juarez del Valle, Marianela; Savoy de Giori, Graciela; LeBlanc, Jean Guy Joseph

    2014-11-17

    The ability of 55 strains from different Lactobacillus species to produce folate was investigated. In order to evaluate folic acid productivity, lactobacilli were cultivated in the folate-free culture medium (FACM). Most of the tested strains needed folate for growth. The production and the extent of vitamin accumulation were distinctive features of individual strains. Lactobacillus amylovorus CRL887 was selected for further studies because of its ability to produce significantly higher concentrations of vitamin (81.2 ± 5.4 μg/L). The safety of this newly identified folate producing strain was evaluated through healthy experimental mice. No bacterial translocation was detected in liver and spleen after consumption of CRL887 during 7 days and no undesirable side effects were observed in the animals that received this strain. This strain in co-culture with previously selected folate producing starter cultures (Lactobacillus bulgaricus CRL871, and Streptococcus thermophilus CRL803 and CRL415) yielded a yogurt containing high folate concentrations (263.1 ± 2.4 μg/L); a single portion of which would provide 15% of the recommended dietary allowance. This is the first report where a Lactobacillus amylovorus strain was successfully used as co-culture for natural folate bio-enrichment of fermented milk. PMID:25217720

  14. Improvement of Ayran quality by the selection of autochthonous microbial cultures.

    Science.gov (United States)

    Baruzzi, Federico; Quintieri, Laura; Caputo, Leonardo; Cocconcelli, PierSandro; Borcakli, Mehlika; Owczarek, Lubomiła; Jasińska, Urszula T; Skąpska, Sylwia; Morea, Maria

    2016-12-01

    Ayran is a traditional Turkish milk drink which is fermented and salted. Inadequate production and storage conditions contribute to its variable organoleptic quality and stability during shelf-life. A thorough physico-chemical, nutritional and microbial characterization of artisanal Ayran was carried out in order to standardize its overall quality without altering its original traits. Ayran microbial ecosystem was largely dominated by Streptococcus thermophilus (ST) and Lactobacillus delbrueckii subsp. bulgaricus (LDB). High counts of other lactic acid bacteria species, including Lactobacillus helveticus (LH), Lactobacillus fermentum (LF), and Lactobacillus paracasei (LP), were also found. Selected LDB, LP and LH strains grew well in milk displaying fast acidification and high proteolysis, differently from ST and LF strains that did not cause noticeable changes. A selected autochthonous three-strain culture (TSC), composed of one strain of LDB, LP and ST, was applied for the pilot-scale production of traditional Ayran. The Ayran produced with this TSC resulted in the most extensive shelf-life (one month) and in the best terms of its nutritional and sensory quality nevertheless altering its typical pleasant yogurt and cottage cheese notes. This TSC is at disposal of SMEs who need to standardize the overall quality of this traditional fermented milk, preserving its typical traits. PMID:27554150

  15. Antioxidant Activity of Peptides from Fermented Milk with Mix Culture of Lactic Acid Bacteria and Yeast

    Directory of Open Access Journals (Sweden)

    Yun Li

    2015-02-01

    Full Text Available The aim of the present study is to investigate the production of antioxidant peptides during milk fermentation with co-culture of Lactic Acid Bacteria (LAB and yeast. Five LAB strains, previously screened with higher hydrolysis activity and Debaryomyces hansenii H2 which isolated from Tibet kefir were used in the study. The peptides separated from fermented milk were analysed antioxidant activity with DPPH radical scavenging, hydroxyl radical scavenging, chelation of metal ions and reducing power assays. The growth of Streptococcus. thermophilus Lactobacillus. delbrueckii ssp. bulgaricus and Lactococcus. lactis was enhanced with co-cultures and L. acidophilus was inhibited in co-culture with yeast. In co-culture with yeast, a significant decrease of the acidity was observed among all the fermentation and the pH reached higher values than in single LAB cultures. Except for L.delbrueckii ssp. bulgaricus, there was no significant difference of protein hydrolysis with other test LAB strains between co-culture and single culture. The co-incubation of LAB with the yeast developed a stronger antioxidant activity in DPPH radical and hydroxyl radical scavenging and no significant (p>0.05 difference in chelation of metal ions. The reducing power of L.delbrueckii ssp. bulgaricus and L. helveticus in co-culture was significant higher than those of single culture.

  16. Preparation of Almond Sour Milk%杏仁酸乳的研制

    Institute of Scientific and Technical Information of China (English)

    权美平

    2013-01-01

    Taking bitter almond and fresh milk as raw materials, the optimum parameters were obtained with main technology including peeling off the skin, debittering process, emulsification operation and fermentation. The results showed that, the optimum parameters of almond sour milk were as follows: the ratio of almond milk to fresh milk 30:70, inoculum size 5%, fermentation time 5 h, lactobacillus bulgaricus I streptococcus thermophilus ratio 1:1 and fermentation temperature 42 ℃. The final product under the optimum conditions showed high sensory qulity.%以苦杏仁为原料和鲜牛乳为原料,经脱皮、去苦、乳化和发酵等主要工艺步骤获得杏仁乳生产最佳技术参数.结果表明,杏仁酸乳发酵工艺的条件为:杏仁乳:牛乳比例为30∶70,接种量5%,发酵时间为5h,按照以保加利亚乳杆菌、嗜热链球菌(1∶1)接种,42℃条件下发酵,可得品质优良的杏仁酸乳.

  17. Suitability of a new mixed-strain starter for manufacturing uncooked raw ewe's milk cheeses.

    Science.gov (United States)

    Feutry, Fabienne; Torre, Paloma; Arana, Ines; Garcia, Susana; Pérez Elortondo, Francisco J; Berthier, Françoise

    2016-06-01

    Most raw milk Ossau-Iraty cheeses are currently manufactured on-farm using the same commercial streptococcal-lactococcal starter (S1). One way to enhance the microbial diversity that gives raw milk its advantages for cheese-making is to formulate new starters combining diverse, characterized strains. A new starter (OI) combining 6 raw milk strains of lactococci, recently isolated and characterized, was tested in parallel with the current starter by making 12 Ossau-Iraty raw milk cheeses at 3 farmhouses under the conditions prevailing at each farm. Compliance of the sensory characteristics with those expected by the Ossau-Iraty professionals, physicochemical parameters and coliforms were quantified at key manufacturing steps. The new starter OI gave cheeses having proper compliance but having lower compliance than the S1 cheeses under most manufacturing conditions, while managing coliform levels equally well as starter S1. This lower compliance relied more on the absence of Streptococcus thermophilus in starter OI, than on the nature of the lactoccocal strains present in starter OI. The study also shows that variations in 5 technological parameters during the first day of manufacture, within the range of values applied in the 3 farmhouses, are powerful tools for diversifying the scores for the sensory characteristics investigated. PMID:26919818

  18. Screening of lactic acid bacteria with high autolysis rate by N+-implantation

    International Nuclear Information System (INIS)

    In order to obtain lactic acid bacteria with high autolysis rate, Streptococcus salivarius ssp. thermophilus GS1 and Lactobacillus delbrueckii ssp. bulgaricus LD3 were mutated by 50 keV N+ ions implantation. The results indicated that the survival rate curve took a saddle shape in the range of 1 x 2.6 x 1013 ∼ 6 x 2.6 x 1013 and the total mutation rate was 57% ∼ 74%. The survival rate were 25% ∼ 33% on the suitable dose 4 x 2.6 x 1013 ion/cm2. Among the mutated strains with mutation rate in the range of 127.98% ∼-51.96%, the highest autolysis rate mutation strains were named LD3-A3 and GS1-B13. Compare with original strains, autolysis rates of LD3-A3 and GS1-B13 increased by 127.98% and 115.11% respectively. Fermentation properties of LD3-A3 and GS1-B13 were stable after 5 generation transfer inoculation. It indicates that the ion implantation technique is a feasible method in lactic acid bacteria breeding. (authors)

  19. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    International Nuclear Information System (INIS)

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

  20. Structural basis for gene regulation by a B12-dependent photoreceptor.

    Science.gov (United States)

    Jost, Marco; Fernández-Zapata, Jésus; Polanco, María Carmen; Ortiz-Guerrero, Juan Manuel; Chen, Percival Yang-Ting; Kang, Gyunghoon; Padmanabhan, S; Elías-Arnanz, Montserrat; Drennan, Catherine L

    2015-10-22

    Photoreceptor proteins enable organisms to sense and respond to light. The newly discovered CarH-type photoreceptors use a vitamin B12 derivative, adenosylcobalamin, as the light-sensing chromophore to mediate light-dependent gene regulation. Here we present crystal structures of Thermus thermophilus CarH in all three relevant states: in the dark, both free and bound to operator DNA, and after light exposure. These structures provide visualizations of how adenosylcobalamin mediates CarH tetramer formation in the dark, how this tetramer binds to the promoter -35 element to repress transcription, and how light exposure leads to a large-scale conformational change that activates transcription. In addition to the remarkable functional repurposing of adenosylcobalamin from an enzyme cofactor to a light sensor, we find that nature also repurposed two independent protein modules in assembling CarH. These results expand the biological role of vitamin B12 and provide fundamental insight into a new mode of light-dependent gene regulation. PMID:26416754