Journal articles: 'Lactobacillus delbrueckii subsp. bulgaricus'

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Frengova, Ginka I., Emilina D. Simova, Dora M. Beshkova, and Zhelyasko I. Simov. "Exopolysaccharides Produced by Lactic Acid Bacteria of Kefir Grains." Zeitschrift für Naturforschung C 57, no. 9-10 (October 1, 2002): 805–10. http://dx.doi.org/10.1515/znc-2002-9-1009.

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A Lactobacillus delbrueckii subsp. bulgaricus HP1 strain with high exopolysaccharide activity was selected from among 40 strains of lactic acid bacteria, isolated from kefir grains. By associating the Lactobacillus delbrueckii subsp. bulgaricus HP1 strain with Streptococcus thermophilus T15, Lactococcus lactis subsp. lactis C15, Lactobacillus helveticus MP12. and Sacharomyces cerevisiae A13, a kefir starter was formed. The associated cultivation of the lactobacteria and yeast had a positive effect on the exopolysaccharide activity of Lactobacillus delbrueckii subsp. bulgaricus HP1. The maximum exopolysaccharide concentration of the starter culture exceeded the one by the Lactobacillus delbrueckii subsp. bulgaricus HP1 monoculture by approximately 1.7 times, and the time needed to reach the maximum concentration (824.3 mg exopolysacharides/l) was shortened by 6 h. The monomer composition of the exopolysaccharides from the kefir starter culture was represented by glucose and galactose in a 1.0:0.94 ratio, which proves that the polymer synthesized is kefiran.

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GIRAFFA, GIORGIO, and DIEGO MORA. "DNA probe for Lactobacillus delbrueckii subsp. lactis." Journal of Dairy Research 66, no. 2 (May 1999): 303–11. http://dx.doi.org/10.1017/s002202999900343x.

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Lactobacilli are of great commercial value because they are widely used as starters in food fermentation. The species Lactobacillus delbrueckii, which comprises the three subspecies bulgaricus, lactis and delbrueckii, is important in dairy products and vegetables. The subspecies bulgaricus is present in yogurt, and subspecies lactis is recovered from whey, starter cultures and cheeses (Stiles & Holzapfel, 1997). It is unusual to recover Lb. delbrueckii subsp. delbrueckii (Lb. delbrueckii) from dairy products, from which Lb. delbrueckii subsp. lactis (Lb. lactis) and subsp. bulgaricus (Lb. bulgaricus) are typically isolated. However, given the similarity of these two latter subspecies, a clear identification of isolates on the basis of phenotype criteria alone is often problematic (Dellaglio, 1989; Millière et al. 1996).The use of DNA probes and methods based on polymerase chain reaction (PCR) have greatly facilitated diagnostic identification of bacteria. For the lactobacilli, DNA probes have been described for Lb. helveticus, Lb. acidophilus, Lb. fermentum, Lb. plantarum and most of the other Lactobacillus species (Pot et al. 1994; Tailliez et al. 1994; Quere et al. 1997). For Lb. delbrueckii, an EcoRI DNA fragment of the plasmid pY85 was used as a probe for this species, although it was not able to discriminate its three subspecies (Delley et al. 1990).In our laboratory, a specific amplification of a DNA fragment of ∼1·7 kbp using universal primers for the amplification of ribosomal RNA (rRNA) genes was found only for dairy isolates of Lb. lactis and not for Lb. bulgaricus, Lb. delbrueckii, Lb. helveticus and Lb. acidophilus (G. Giraffa, P. de Vecchi and L. Rossetti, unpublished results). This prompted us to test the possible use of this fragment as a specific DNA probe for Lb. lactis. To this end, Southern and dot blot hybridization experiments were carried out with total DNA of several strains belonging to different lactic acid bacteria (LAB) species.

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Lapierre, Luciane, Beat Mollet, and Jacques-Edouard Germond. "Regulation and Adaptive Evolution of Lactose Operon Expression in Lactobacillus delbrueckii." Journal of Bacteriology 184, no. 4 (February 15, 2002): 928–35. http://dx.doi.org/10.1128/jb.184.4.928-935.2002.

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ABSTRACT Lactobacillus delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis are both used in the dairy industry as homofermentative lactic acid bacteria in the production of fermented milk products. After selective pressure for the fast fermentation of milk in the manufacture of yogurts, L. delbrueckii subsp. bulgaricus loses its ability to regulate lac operon expression. A series of mutations led to the constitutive expression of the lac genes. A complex of insertion sequence (IS) elements (ISL4 inside ISL5), inserted at the border of the lac promoter, induced the loss of the palindromic structure of one of the operators likely involved in the binding of regulatory factors. A lac repressor gene was discovered downstream of the β-galactosidase gene of L. delbrueckii subsp. lactis and was shown to be inactivated by several mutations in L. delbrueckii subsp. bulgaricus. Regulatory mechanisms of the lac gene expression of L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis were compared by heterologous expression in Lactococcus lactis of the two lac promoters in front of a reporter gene (β-glucuronidase) in the presence or absence of the lac repressor gene. Insertion of the complex of IS elements in the lac promoter of L. delbrueckii subsp. bulgaricus increased the promoter's activity but did not prevent repressor binding; rather, it increased the affinity of the repressor for the promoter. Inactivation of the lac repressor by mutations was then necessary to induce the constitutive expression of the lac genes in L. delbrueckii subsp. bulgaricus.

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Samadlouie, Hamid Reza, Shahrokh Gharanjik, and Zohreh Beygom Tabatabaie. "Optimization of the Production of ε-Poly-L-Lysine by Novel Producer Lactic Acid Bacteria Isolated from Traditional Dairy Products." BioMed Research International 2020 (October 5, 2020): 1–8. http://dx.doi.org/10.1155/2020/2145656.

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New strains of lactic acid bacteria (LAB) were isolated from different traditional dairy products. Six new strains named Lactobacillus delbrueckii strain A01, Lactobacillus delbrueckii subsp. bulgaricus strain D01, Lactobacillus delbrueckii subsp. bulgaricus strain E01, Lactococcus lactis strain G01, Lactobacillus delbrueckii strain C01, and Lactobacillus delbrueckii subsp. bulgaricus strain F01 were identified using 16S rDNA sequencing, morphological and biochemical traits. All strains have been registered in the National Center for Biotechnology Information (NCBI) with accession numbers MN611241.1, MN611300.1, MN611301.1, MN611303.1, MN611241.1, and MN611299.1, respectively. Having found ε-Poly-L-Lysine (ε-PL) in all strains isolated, Lactobacillus delbrueckii strain A01 was identified as an active producer of ε-Poly-L-Lysine (ε-PL). The one-factor-at-a-time method and central composite design were applied to optimize ε-Poly-L-Lysine (ε-PL). A predicted 200 ppm of ε-PL was obtained in the medium containing the lowest level of glucose, 25 g/l, and yeast extract, 6 g/l.

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Petry, Sandrine, Satanislav Dusko Ehrlich, and Emmanuelle Maguin. "Exopolysaccharides de Lactobacillus delbrueckii subsp. bulgaricus." Sciences des Aliments 22, no. 1-2 (April 28, 2002): 143–49. http://dx.doi.org/10.3166/sda.22.143-149.

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Cebeci, Aysun, and G. Candan Gürakan. "Molecular methods for identification of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus using methionine biosynthesis and 16S rRNA genes." Journal of Dairy Research 75, no. 4 (July 14, 2008): 392–98. http://dx.doi.org/10.1017/s0022029908003543.

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Yoghurt and starter culture producers are still searching strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus to produce healthier yogurt with longer shelf life, better texture, taste and quality. However, selective identification of Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus from a mixed population using microbiological and biochemical methods is difficult, time consuming and may not be accurate. In this study, a quick, sensitive and accurate method is proposed to identify both Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus using PCR. The method is comprised of two parts. In the first part, methionine biosynthesis genes, known to be present in both species were partially amplified by designed primers (cysmet2F and cysmet2R). Partial amplification of the methionine biosynthesis gene which gives 700 bp fragment resulted in selective identification of Lb. bulgaricus and Strep. thermophilus. All 16 Lb. bulgaricus and 6 Strep. thermophilus isolates assessed by this method gave the expected amplification. On the other hand, further analysis of other closely related species with the same primers have indicated that the same product was also amplified in two more lactobacilli namely, Lb. delbrueckii subsp. lactis and Lb. helveticus species. Thus, in the second part of the method, further differentiation of Lb. delbrueckii subsp. bulgaricus and Strep. thermophilus from each other and these species was achieved using restriction analysis of 16S rRNA gene with EcoRI.

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Henri-Dubernet, Ségolène, Nathalie Desmasures, and Micheline Guéguen. "Diversity and dynamics of lactobacilli populations during ripening of RDO Camembert cheese." Canadian Journal of Microbiology 54, no. 3 (March 2008): 218–28. http://dx.doi.org/10.1139/w07-137.

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The diversity and dynamics of Lactobacillus populations in traditional raw milk Camembert cheese were monitored throughout the manufacturing process in 3 dairies. Culture-dependent analysis was carried out on isolates grown on acidified de Man – Rogosa – Sharpe agar and Lactobacillus anaerobic de Man Rogosa Sharpe agar supplemented with vancomycin and bromocresol green media. The isolates were identified by polymerase chain reaction – temperature gradient gel electrophoresis (PCR–TGGE) and (or) species-specific PCR and (or) sequencing, and Lactobacillus paracasei and Lactobacillus plantarum isolates were characterized by pulsed field gel electrophoresis (PFGE). Milk and cheese were subjected to culture-independent analysis by PCR–TGGE. Presumed lactobacilli were detected by plate counts throughout the ripening process. However, molecular analysis of total DNA and DNA of isolates failed to detect Lactobacillus spp. in certain cases. The dominant species in the 3 dairies was L. paracasei. PFGE analysis revealed 21 different profiles among 39 L. paracasei isolates. Lactobacillus plantarum was the second most isolated species, but it occurred nearly exclusively in one dairy. The other species isolated were Lactobacillus parabuchneri , Lactobacillus fermentum , Lactobacillus acidophilus , Lactobacillus helveticus , a Lactobacillus psittaci/delbrueckii subsp. bulgaricus/gallinarum/crispatus group, Lactobacillus rhamnosus , Lactobacillus delbrueckii subsp. bulgaricus, L. delbrueckii subsp. lactis, Lactobacillus brevis , Lactobacillus kefiri , and Lactobacillus perolens. Lactobacilli diversity at the strain level was high. Dynamics varied among dairies, and each cheese exhibited a specific picture of species and strains.

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ASLIM, BELMA, DERYA ONAL, and YAVUZ BEYATLI. "Factors Influencing Autoaggregation and Aggregation of Lactobacillus delbrueckii subsp. bulgaricus Isolated from Handmade Yogurt." Journal of Food Protection 70, no. 1 (January 1, 2007): 223–27. http://dx.doi.org/10.4315/0362-028x-70.1.223.

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Of 26 Lactobacillus delbrueckii subsp. bulgaricus strains isolated from yogurt, strains B2 and 22, which produce low levels (28 and 21 mg liter−1, respectively) of extracellular polysaccharides (EPSs), and strains B3 and G12, which produce high EPS levels (211 and 175 mg liter−1, respectively), were selected for further study. The two high EPS-producing strains showed a significant autoaggregation and coaggregation ability with Escherichia coli ATCC 11230 (P < 0.05). Moreover, the effect of bile was evaluated on autoaggregation and hydrophobicity. Autoaggregation and hydrophobicity of these L. delbrueckii subsp. bulgaricus strains decreased after treatment with bile. Only the high EPS-producing L. delbrueckii subsp. bulgaricus strain B3 showed greater autoaggregation (80%) and hydrophobicity (86%) than the other strains after bile treatment. When these strains were assessed for the inhibition of E. coli ATCC 11230 in coculture, L. delbrueckii subsp. bulgaricus B3 completely inhibited E. coli during 24 and 48 h of incubation. This investigation showed that a high EPS production and coaggregation ability may be important in the selection of probiotic strains.

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Serror, Pascale, Takashi Sasaki, S. Dusko Ehrlich, and Emmanuelle Maguin. "Electrotransformation of Lactobacillus delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis with Various Plasmids." Applied and Environmental Microbiology 68, no. 1 (January 2002): 46–52. http://dx.doi.org/10.1128/aem.68.1.46-52.2002.

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ABSTRACT We describe, for the first time, a detailed electroporation procedure for Lactobacillus delbrueckii. Three L. delbrueckii strains were successfully transformed. Under optimal conditions, the transformation efficiency was 104 transformants per μg of DNA. Using this procedure, we identified several plasmids able to replicate in L. delbrueckii and integrated an integrative vector based on phage integrative elements into the L. delbrueckii subsp. bulgaricus chromosome. These vectors provide a good basis for developing molecular tools for L. delbrueckii and open the field of genetic studies in L. delbrueckii.

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Do Carmo, A., M. De Oliveira, D. Da Silva, S. Castro, A. Borges, A. De Carvalho, and C. De Moraes. "Genes involved in lactose catabolism and organic acid production during growth of Lactobacillus delbrueckii UFV H2b20 in skimmed milk." Beneficial Microbes 3, no. 1 (March 1, 2012): 23–32. http://dx.doi.org/10.3920/bm2011.0037.

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There are three main reasons for using lactic acid bacteria (LAB) as starter cultures in industrial food fermentation processes: food preservation due to lactic acid production; flavour formation due to a range of organic molecules derived from sugar, lipid and protein catabolism; and probiotic properties attributed to some strains of LAB, mainly of lactobacilli. The aim of this study was to identify some genes involved in lactose metabolism of the probiotic Lactobacillus delbrueckii UFV H2b20, and analyse its organic acid production during growth in skimmed milk. The following genes were identified, encoding the respective enzymes: ldh – lactate dehydrogenase, adhE – Ldb1707 acetaldehyde dehydrogenase, and ccpA-pepR1 – catabolite control protein A. It was observed that L. delbrueckii UFV H2b20 cultivated in different media has the unexpected ability to catabolyse galactose, and to produce high amounts of succinic acid, which was absent in the beginning, raising doubts about the subspecies in question. The phylogenetic analyses showed that this strain can be compared physiologically to L. delbrueckii subsp. bulgaricus and L. delbrueckii subsp. lactis, which are able to degrade lactose and can grow in milk. L. delbrueckii UFV H2b20 sequences have grouped with L. delbrueckii subsp. bulgaricus ATCC 11842 and L. delbrueckii subsp. bulgaricus ATCC BAA-365, strengthening the classification of this probiotic strain in the NCFM group proposed by a previous study. Additionally, L. delbrueckii UFV H2b20 presented an evolutionary pattern closer to that of probiotic Lactobacillus acidophilus NCFM, corroborating the suggestion that this strain might be considered as a new and unusual subspecies among L. delbrueckii subspecies, the first one identified as a probiotic. In addition, its unusual ability to metabolise galactose, which was significantly consumed in the fermentation medium, might be exploited to produce low-browning probiotic Mozzarella cheeses, a desirable property for pizza cheeses.

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Laiño, Jonathan Emiliano, Jean Guy LeBlanc, and Graciela Savoy de Giori. "Production of natural folates by lactic acid bacteria starter cultures isolated from artisanal Argentinean yogurts." Canadian Journal of Microbiology 58, no. 5 (May 2012): 581–88. http://dx.doi.org/10.1139/w2012-026.

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Folate is a B-group vitamin that cannot be synthesized by humans and must be obtained exogenously. Although some species of lactic acid bacteria (LAB) can produce folates, little is known about the production of this vitamin by yogurt starter cultures. Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were isolated from artisanal Argentinean yogurts and were grown in folate-free culture medium (FACM) and nonfat milk after which intracellular and extracellular folate production were evaluated. From the initial 92 isolated LAB strains, 4 L. delbrueckii subsp. bulgaricus and 32 S. thermophilus were able to grow in the absence of folate. Lactobacillus delbrueckii subsp. bulgaricus CRL 863 and S. thermophilus CRL 415 and CRL 803 produced the highest extracellular folate levels (from 22.3 to 135 µg/L) in FACM. In nonfat milk, these strains were able to increase the initial folate concentrations by almost 190%. This is the first report where native strains of L. delbrueckii subsp. bulgaricus were shown to produce natural folate. The LAB strains identified in this study could be used in developing novel fermented products bio-enriched in natural folates that could in turn be used as an alternative to fortification with the controversial synthetic chemical folic acid.

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Serror, Pascale, Golnar Ilami, Hichem Chouayekh, S. Dusko Ehrlich, and Emmanuelle Maguin. "Transposition in Lactobacillus delbrueckii subsp. bulgaricus: identification of two thermosensitive replicons and two functional insertion sequences." Microbiology 149, no. 6 (June 1, 2003): 1503–11. http://dx.doi.org/10.1099/mic.0.25827-0.

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In this report, it is shown that the rolling circle replicon pG+host and the theta replicon pIP501 are thermosensitive in Lactobacillus delbrueckii subsp. bulgaricus (Lactobacillus bulgaricus). Using a pIP501 derivative as a delivery vector for six insertion sequences originating from lactic acid bacteria, it is shown that IS1223 and IS1201 transpose in L. bulgaricus.

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Siragusa, S., M. De Angelis, R. Di Cagno, C. G. Rizzello, R. Coda, and M. Gobbetti. "Synthesis of γ-Aminobutyric Acid by Lactic Acid Bacteria Isolated from a Variety of Italian Cheeses." Applied and Environmental Microbiology 73, no. 22 (September 21, 2007): 7283–90. http://dx.doi.org/10.1128/aem.01064-07.

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ABSTRACT The concentrations of γ-aminobutyric acid (GABA) in 22 Italian cheese varieties that differ in several technological traits markedly varied from 0.26 to 391 mg kg−1. Presumptive lactic acid bacteria were isolated from each cheese variety (total of 440 isolates) and screened for the capacity to synthesize GABA. Only 61 isolates showed this activity and were identified by partial sequencing of the 16S rRNA gene. Twelve species were found. Lactobacillus paracasei PF6, Lactobacillus delbrueckii subsp. bulgaricus PR1, Lactococcus lactis PU1, Lactobacillus plantarum C48, and Lactobacillus brevis PM17 were the best GABA-producing strains during fermentation of reconstituted skimmed milk. Except for L. plantarum C48, all these strains were isolated from cheeses with the highest concentrations of GABA. A core fragment of glutamate decarboxylase (GAD) DNA was isolated from L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48 by using primers based on two highly conserved regions of GAD. A PCR product of ca. 540 bp was found for all the strains. The amino acid sequences deduced from nucleotide sequence analysis showed 98, 99, 90, and 85% identity to GadB of L. plantarum WCFS1 for L. paracasei PF6, L. delbrueckii subsp. bulgaricus PR1, L. lactis PU1, and L. plantarum C48, respectively. Except for L. lactis PU1, the three lactobacillus strains survived and synthesized GABA under simulated gastrointestinal conditions. The findings of this study provide a potential basis for exploiting selected cheese-related lactobacilli to develop health-promoting dairy products enriched in GABA.

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MEDINA, L. M., and R. JORDANO. "Survival of Constitutive Microflora in Commercially Fermented Milk Containing Bifidobacteria During Refrigerated Storage." Journal of Food Protection 57, no. 8 (August 1, 1994): 731–33. http://dx.doi.org/10.4315/0362-028x-57.8.731.

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The survival of constitutive microflora was studied in one batch (n = 50) of fermented milk containing bifidobacteria produced in Spain during storage at 7°C. Levels of Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and Bifidobacterium spp. and the pH of the product were determined on the day of collection and after 10, 17, 24, 28, 31, 36, 42, 51, and 84 d of storage. Initial populations of streptococci, lactobacilli, and bifidobacteria were 2.6 × 108, 5.1 × 107, and 7.4 × 106 CFU/g, respectively. The S. salivarius subsp. thermophilus population increased slightly after 10 d and then decreased during further refrigerated storage. Numbers of Bifidobacterium and L. delbrueckii subsp. bulgaricus decreased faster during storage. After 24 d (the reported shelf life of the product), levels of streptococci decreased only 10.7% as compared to decreases of 85.4 and 92.6% for lactobacilli and bifidobacteria, respectively. The pH values were between 4.57 and 3.81.

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GILBERT, CHRISTOPHE, BRIGITTE BLANC, JACQUES FROT-COUTAZ, RAYMOND PORTALIER, and DANIÈLE ATLAN. "Comparison of cell surface proteinase activities within the Lactobacillus genus." Journal of Dairy Research 64, no. 4 (November 1997): 561–71. http://dx.doi.org/10.1017/s0022029997002355.

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Whole cells of Lactobacillus delbrueckii subsp. bulgaricus CNRZ 397 (Lb. bulgaricus CNRZ 397) are able to hydrolyse α- and β-caseins. We have isolated a mutant of Lb. bulgaricus altered for growth in milk and unable to hydrolyse α- or β-casein. Normal growth was restored by adding amino acids or tryptone to milk. No significant difference between the peptidase activities of parent and mutant strains was observed. The cell surface caseinolytic activities of three lactobacilli species and Lactococcus lactis subsp. lactis (Lc. lactis) were compared. As expected, the characteristics of the cell surface proteinase activity of Lb. casei were similar to those of Lc. lactis. We showed that the cleavage specificities of the cell surface proteinase activities from lactobacilli were species-dependent and at least three types of activity were distinguished. The regulation of the biosynthesis of cell surface proteinase activities was medium-dependent and different within the Lactobacillus genus and even within the Lb. delbrueckii species. In contrast to Lb. bulgaricus, the cell surface proteinase activity of Lb. lactis was totally inhibited in a medium rich in peptides or amino acids. In contrast, the cell surface of Lb. helveticus probably displayed two proteinases with different cleavage specificities and with a biosynthesis regulation sensitive to different medium components.

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Zhang, Shuang, Lanwei Zhang, Lili Zhang, Zhen Feng, and Nditange Shigwedha. "Screening, purification, and characterization of proteinase from 3 Lactobacillus delbrueckii subsp. bulgaricus." RSC Advances 5, no. 114 (2015): 93733–38. http://dx.doi.org/10.1039/c5ra16767a.

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Lick, Sonja, Karsten Drescher, and Knut J. Heller. "Survival of Lactobacillus delbrueckiisubsp. bulgaricus and Streptococcus thermophilusin the Terminal Ileum of Fistulated Göttingen Minipigs." Applied and Environmental Microbiology 67, no. 9 (September 1, 2001): 4137–43. http://dx.doi.org/10.1128/aem.67.9.4137-4143.2001.

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ABSTRACT The ability of Lactobacillus delbrueckii subsp.bulgaricus and Streptococcus thermophilusadministered in yogurt to survive the passage through the upper gastrointestinal tract was investigated with Göttingen minipigs that were fitted with ileum T-cannulas. After ingestion of yogurt containing viable microorganisms, ileostomy samples were collected nearly every hour beginning 3 h after food uptake. Living L. delbrueckii subsp. bulgaricus andS. thermophilus were detected in the magnitude of 106 to 107 per gram of intestinal contents (wet weight) in all animals under investigation. A calculation of the minimum amount of surviving bacteria that had been administered is presented. Total DNA extracted from ileostomy samples was subjected to PCR, which was species specific for L. delbrueckii andS. thermophilus and subspecies specific for L. delbrueckii subsp. bulgaricus. All three bacterial groups could be detected by PCR after yogurt uptake but not after uptake of a semisynthetic diet. One pig apparently had developed an endogenous L. delbrueckii flora. When heat-treated yogurt was administered, L. delbrueckii was detected in all animals. S. thermophilus or L. delbrueckiisubsp. bulgaricus was not detected, indicating that heat-inactivated cells and their DNAs had already been digested and their own L. delbrueckii flora had been stimulated for growth.

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Stachelska, Milena Alicja, and Roberta Foligni. "Development of a time-effective and highly specific quantitative real-time polymerase chain reaction assay for the identification of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in artisanal raw cow’s milk cheese." Acta Veterinaria Brno 87, no. 3 (2018): 301–8. http://dx.doi.org/10.2754/avb201887030301.

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The first objective of this work included the development of real-time polymerase chain reaction (RT-PCR) which is also known as quantitative polymerase chain reaction (qPCR) assays to quantify two species of lactic acid bacteria which play a very important role in cheese ripening: Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The second objective was the comparison of qPCR and plate counts of these two species present in raw cow’s milk cheese samples during different stages of ripening. Thirty-three deoxyribonucleic acid (DNA) samples coming from seven different bacterial species, which were phylogenetically related or commonly isolated from raw milk and dairy products, were chosen as positive and negative controls. The qPCR assays showed a high quantification capacity characterised by their linearity (R2 > 0.998), PCR efficiencies which were within the range 78.0–90.0% for L. delbrueckii subsp. bulgaricus, and 93.6–100.5% for S. thermophilus, and quantification limit (103 gene copies/ml for L. delbrueckii subsp. bulgaricus and 10 gene copies/ml for S. thermophilus). The importance of our study is in the monitoring of changes in populations of L. delbrueckii subsp. bulgaricus and S. thermophilus contributing to cheese ripening using the newly designed qPCR assay.

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Karapetkov, N., R. Georgieva, N. Rumyan, and E. Karaivanova. "Antibiotic susceptibility of different lactic acid bacteria strains." Beneficial Microbes 2, no. 4 (December 1, 2011): 335–39. http://dx.doi.org/10.3920/bm2011.0016.

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Five lactic acid bacteria (LAB) strains belonging to species Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis and Streptococcus thermophilus were tested for their susceptibility to 27 antibiotics. The minimum inhibitory concentrations of each antimicrobial were determined using a microdilution test. Among the strains a high susceptibility was detected for most of the cell-wall synthesis inhibitors (penicillins, cefoxitin and vancomycin) and resistance toward inhibitors of DNA synthesis (trimethoprim/sulfonamides and fluoroquinolones). Generally, the Lactobacillus strains were inhibited by antibiotics such as chloramphenicol, erythromycin and tetracycline at breakpoint levels lower or equal to the levels defined by the European Food Safety Authority. Despite the very similar profile of S. thermophilus LC201 to lactobacilli, the detection of resistance toward erythromycin necessitates the performance of additional tests in order to prove the absence of transferable resistance genes.

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Frengova, Ginka I., Emilina D. Simova, Dora M. Beshkova, and Zhelyasko I. Simov. "Production and monomer composition of exopolysaccharides by yogurt starter cultures." Canadian Journal of Microbiology 46, no. 12 (December 1, 2000): 1123–27. http://dx.doi.org/10.1139/w00-103.

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As components of starter cultures for Bulgarian yogurt, Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus revealed extensive exopolysaccharide (EPS) production activity when cultivated in whole cow's milk. The polymer-forming activity of thermophilic streptococci was lower (230-270 mg EPS/L) than that of the lactobacilli (400-540 mg EPS/L). Mixed cultures stimulated EPS production in yogurt manufacture, and a maximum concentration of 720-860 mg EPS/L was recorded after full coagulation of milk. The monomer structure of the exopolysaccharides formed by the yogurt starter cultures principally consists of galactose and glucose (1:1), with small amounts of xylose, arabinose, and/or mannose.Key words: Streptococcus thermophilus, Lactobacillus bulgaricus, starter cultures, yogurt, exopolysaccharides.

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Tanigawa, Kana, and Koichi Watanabe. "Multilocus sequence typing reveals a novel subspeciation of Lactobacillus delbrueckii." Microbiology 157, no. 3 (March 1, 2011): 727–38. http://dx.doi.org/10.1099/mic.0.043240-0.

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Currently, the species Lactobacillus delbrueckii is divided into four subspecies, L. delbrueckii subsp. delbrueckii, L. delbrueckii subsp. bulgaricus, L. delbrueckii subsp. indicus and L. delbrueckii subsp. lactis. These classifications were based mainly on phenotypic identification methods and few studies have used genotypic identification methods. As a result, these subspecies have not yet been reliably delineated. In this study, the four subspecies of L. delbrueckii were discriminated by phenotype and by genotypic identification [amplified-fragment length polymorphism (AFLP) and multilocus sequence typing (MLST)] methods. The MLST method developed here was based on the analysis of seven housekeeping genes (fusA, gyrB, hsp60, ileS, pyrG, recA and recG). The MLST method had good discriminatory ability: the 41 strains of L. delbrueckii examined were divided into 34 sequence types, with 29 sequence types represented by only a single strain. The sequence types were divided into eight groups. These groups could be discriminated as representing different subspecies. The results of the AFLP and MLST analyses were consistent. The type strain of L. delbrueckii subsp. delbrueckii, YIT 0080T, was clearly discriminated from the other strains currently classified as members of this subspecies, which were located close to strains of L. delbrueckii subsp. lactis. The MLST scheme developed in this study should be a useful tool for the identification of strains of L. delbrueckii to the subspecies level.

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Azcárate-Peril, M. Andrea, and Raúl R. Raya. "Sequence analysis of pLBB1, a cryptic plasmid from Lactobacillus delbrueckii subsp. bulgaricus." Canadian Journal of Microbiology 48, no. 2 (February 1, 2002): 105–12. http://dx.doi.org/10.1139/w01-137.

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The first report of the complete nucleotide sequence of a cryptic plasmid from Lactobacillus delbrueckii subsp. bulgaricus (Lactobacillus bulgaricus) is presented. The plasmid pLBB1 consists of 6127 bp with a GC content of 44.8%. No ssDNA was detected by hybridization experiments, which is consistent with the notion that pLBB1 does not replicate by a rolling circle mechanism. A putative replication region of pLBB1 was cloned and found to be functional in Lactobacillus johnsonii and Lactococcus lactis. Plasmid pLBB1 showed significant DNA sequence identity with plasmid pLL1212 from Lactobacillus delbrueckii subsp. lactis (Lactobacillus lactis) CRL1212 (GenBank accession No. AF109691). Four open reading frames (ORFs) larger than 100 amino acids were identified. ORFA shared similarity with a putative primasehelicase system, and ORFB and ORFC exhibited limited identity with a mobilization protein and a transposase, respectively. Curing experiments did not allowed us to assign a function to the ORFs.Key words: Lactobacillus, cryptic plasmid, sequence analysis.

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Fang, Xiang, Yanlin Li, Wei Guo, Wencan Ke, Sisi Bi, Xusheng Guo, and Ying Zhang. "Lactobacillus delbrueckii subsp. bulgaricus F17 and Leuconostoc lactis H52 supernatants delay the decay of strawberry fruits: a microbiome perspective." Food & Function 10, no. 12 (2019): 7767–81. http://dx.doi.org/10.1039/c9fo02079a.

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Lactobacillus delbrueckii subsp. bulgaricus F17 and Leuconostoc lactis H52 as the potential biopreservative, which delayed the decay and changed the structure of microbial community of the ‘Benihoppe’ strawberry fruits.

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MANCA de NADRA, M. C., G. J. ANDUNI, and M. E. FARÍAS. "Influence of Artificial Sweeteners on the Kinetic and Metabolic Behavior of Lactobacillus delbrueckii subsp. bulgaricus." Journal of Food Protection 70, no. 10 (October 1, 2007): 2413–16. http://dx.doi.org/10.4315/0362-028x-70.10.2413.

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The addition of artificial sweeteners to a LAPT (yeast extract, peptone, and tryptone) medium without supplemented sugar increased the growth rate and final biomass of Lactobacillus delbrueckii subsp. bulgaricus YOP 12 isolated from commercial yogurt. Saccharin and cyclamate were consumed during microorganism growth, while the uptake of aspartame began once the medium was glucose depleted. The pH of the media increased as a consequence of the ammonia released into the media supplemented with the sweeteners. The L. delbrueckii subsp. bulgaricus strain was able to grow in the presence of saccharin, cyclamate, or aspartame, and at low sweetener concentrations, the microorganism could utilize cyclamate and aspartame as an energy and carbon source.

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Casey, Eoghan, Jennifer Mahony, Mary O'Connell-Motherway, Francesca Bottacini, Anneleen Cornelissen, Horst Neve, Knut J. Heller, Jean-Paul Noben, Fabio Dal Bello, and Douwe van Sinderen. "Molecular Characterization of Three Lactobacillus delbrueckii subsp. bulgaricus Phages." Applied and Environmental Microbiology 80, no. 18 (July 7, 2014): 5623–35. http://dx.doi.org/10.1128/aem.01268-14.

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ABSTRACTIn this study, three phages infectingLactobacillus delbrueckiisubsp.bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group bL. delbrueckiiphages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations.

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Streit, Fernanda, Georges Corrieu, and Catherine Béal. "Acidification improves cryotolerance of Lactobacillus delbrueckii subsp. bulgaricus CFL1." Journal of Biotechnology 128, no. 3 (February 20, 2007): 659–67. http://dx.doi.org/10.1016/j.jbiotec.2006.11.012.

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Tavşanlı, Hakan, Tülay Elal Mus, Figen Cetinkaya, Ergün Aynaoglu, and Recept Cibik. "Isolation of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus from nature: Technological characterisation and antibiotic resistance." Czech Journal of Food Sciences 39, No. 4 (August 29, 2021): 305–11. http://dx.doi.org/10.17221/296/2020-cjfs.

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Yoghurt fermenting bacteria were isolated from natural sources including plants, dew, and rain samples (total of 300 samples) by the same methods nomadic peoples used for several centuries in Turkey. Inoculation into the reconstituted skim milk followed by planting on specific media and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis allowed for the identification of 18 Lactobacillus delbrueckii subsp. and 26 Streptococcus thermophilus. A multiplex polymerase chain reaction (PCR) assay applied to lactobacilli enabled the identification of 5 isolates as L. delbrueckii subsp. bulgaricus. The isolates showed a varying range of acidification rates and proteolytic activity in reconstituted skimmed milk (RSM). S. thermophilus isolates showed a broader range of resistance and the most frequent resistance was observed for streptomycin (69.2%), gentamycin (65.3%), clindamycin (61.5%), ampicillin (61.5%), kanamycin (53.8%), and erythromycin (50%). For L. delbrueckii subsp. the highest resistance was determined for vancomycin (38.8%), ciprofloxacin (33.3%), and penicillin (27.8%). The frequency of multiple resistance was tested on 14 different antimicrobials determining that 19 S. thermophilus (73%) and 3 L. delbrueckii subsp. (16.7%) demonstrated resistance to more than three different antibiotics. In contrast to this wide-ranging resistance, five isolates from each genus were found to be susceptible to all tested antibiotics. The present study indicates that lactic acid bacteria (LAB) isolated from nature may have broad-range of resistance to antibiotics and could be a source for the transfer of resistance.

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ZAVAGLIA, ANDREA GÓMEZ, EDGARDO A. DISALVO, and GRACIELA L. DE ANTONI. "Fatty acid composition and freeze–thaw resistance in lactobacilli." Journal of Dairy Research 67, no. 2 (May 2000): 241–47. http://dx.doi.org/10.1017/s0022029900004179.

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The fatty acid composition and freeze–thaw resistance of eight strains of thermophilic lactobacilli were studied. Seven of these contained the same polar and neutral lipids, the five major components making up 90% of the cellular fatty acid pool being 14[ratio ]0, 16[ratio ]0, 16[ratio ]1, 18[ratio ]1 and C19 cyclopropane (cyc19[ratio ]0). Strain comparison by means of cluster analysis based on the fatty acid ratios using the overlap coefficient revealed two well defined clusters. One was formed by three strains of species Lactobacillus delbrueckii subsp. lactis and Lb. delbrueckii subsp. delbrueckii, the other included five strains of the species Lb. delbrueckii subsp. bulgaricus, Lb. acidophilus and Lb. helveticus. Resistance of strains with a high content of unsaturated fatty acids (66–70%) decreased with increasing cyc19[ratio ]0 concentrations. In contrast, in strains with a low concentration of unsaturated fatty acids (42–49%), increasing cyc19[ratio ]0 levels were associated with increased freeze–thaw resistance.

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Gatti, Fornasari, and Neviani. "Differentiation of Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus delbrueckii subsp. lactis by SDS-PAGE of cell-wall proteins." Letters in Applied Microbiology 32, no. 5 (May 31, 2001): 352–56. http://dx.doi.org/10.1046/j.1472-765x.2001.00917.x.

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Ragoubi, Chaima, Laura Quintieri, Donato Greco, Amel Mehrez, Imed Maatouk, Vito D’Ascanio, Ahmed Landoulsi, and Giuseppina Avantaggiato. "Mycotoxin Removal by Lactobacillus spp. and Their Application in Animal Liquid Feed." Toxins 13, no. 3 (March 2, 2021): 185. http://dx.doi.org/10.3390/toxins13030185.

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The removal of mycotoxins from contaminated feed using lactic acid bacteria (LAB) has been proposed as an inexpensive, safe, and promising mycotoxin decontamination strategy. In this study, viable and heat-inactivated L. acidophilus CIP 76.13T and L. delbrueckii subsp. bulgaricus CIP 101027T cells were investigated for their ability to remove aflatoxin B1 (AFB1), ochratoxin A (OTA), zearalenone (ZEA), and deoxynivalenol (DON) from MRS medium and PBS buffer over a 24 h period at 37 °C. LAB decontamination activity was also assessed in a ZEA-contaminated liquid feed (LF). Residual mycotoxin concentrations were determined by UHPLC-FLD/DAD analysis. In PBS, viable L. acidophilus CIP 76.13T and L. delbrueckii subsp. bulgaricus CIP 101027T cells removed up to 57% and 30% of ZEA and DON, respectively, while AFB1 and OTA reductions were lower than 15%. In MRS, 28% and 33% of ZEA and AFB1 were removed, respectively; OTA and DON reductions were small (≤15%). Regardless of the medium, heat-inactivated cells produced significantly lower mycotoxin reductions than those obtained with viable cells. An adsorption mechanism was suggested to explain the reductions in AFB1 and OTA, while biodegradation could be responsible for the removal of ZEA and DON. Both viable LAB strains reduced ZEA by 23% in contaminated LF after 48 h of incubation. These findings suggest that LAB strains of L. acidophilus CIP 76.13T and L. delbrueckii subsp. bulgaricus CIP 101027T may be applied in the feed industry to reduce mycotoxin contamination.

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Liu, Fei, Yue Hua Jiao, and Gui Cheng Huo. "Optimization of Co-Culture Condition for Lactobacillus delbrueckii subsp. bulgaricus with Weak Post-Acidification Ability and Streptococcus thermophilus." Advanced Materials Research 655-657 (January 2013): 1982–86. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.1982.

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To obtain high quality yoghurt starter with low post-acidification, the characteristics of mixed fermentation of yoghurt strains were studied. Lactobacillus delbrueckii subsp. bulgaricus KLDS 1.9201-11 with reduced post-acidification and Streptococcus thermophilus KLDS 3.9210 were cultivated in 2.5L fermenter with different culture temperature, initial pH and proportion of inoculums, and of which reproductive activity and ratio of viable cell count were compared. It was beneficial for the balance of final ratio of viable cell count between starter strains at the end of fermentation, when grew at 42°C, pH6.2, and the proportion of inoculums of Lactobacillus delbrueckii subsp. bulgaricus KLDS 1.9201-11 and Streptococcus thermophilus KLDS 3.9210 was 2 to 1. These results showed that different culture conditions could affect symbiotic growth of yoghurt strains, and different growth mode was an important prerequisite for collaboration growth of mixed strain and acquisition of yoghurt starter with high quality.

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Torriani, Sandra, Giacomo Zapparoli, and Franco Dellaglio. "Use of PCR-Based Methods for Rapid Differentiation of Lactobacillus delbrueckii subsp.bulgaricus and L. delbrueckii subsp.lactis." Applied and Environmental Microbiology 65, no. 10 (October 1, 1999): 4351–56. http://dx.doi.org/10.1128/aem.65.10.4351-4356.1999.

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ABSTRACT Two PCR-based methods, specific PCR and randomly amplified polymorphic DNA PCR (RAPD-PCR), were used for rapid and reliable differentiation of Lactobacillus delbrueckii subsp.bulgaricus and L. delbrueckii subsp.lactis. PCR with a single combination of primers which targeted the proline iminopeptidase (pepIP) gene ofL. delbrueckii subsp. bulgaricus allowed amplification of genomic fragments specific for the two subspecies when either DNA from a single colony or cells extracted from dairy products were used. A numerical analysis of the RAPD-PCR patterns obtained with primer M13 gave results that were consistent with the results of specific PCR for all strains except L. delbrueckii subsp.delbrueckii LMG 6412T, which clustered withL. delbrueckii subsp. lactis strains. In addition, RAPD-PCR performed with primer 1254 provided highly polymorphic profiles and thus was superior for distinguishing individual L. delbrueckii strains.

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Dekumpitiya, N., D. Gamlakshe, S. I. Abeygunawardena, and D. Jayaratne. "Identification of the Microbial Consortium in Sri Lankan Buffalo Milk Curd and their growth in the Presence of Prebiotics." Journal of Food Science and Technology Nepal 9 (April 8, 2016): 20–30. http://dx.doi.org/10.3126/jfstn.v9i0.12579.

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The production and consumption of traditionally fermented buffalo milk curd provides many economical and food security benefits to both producers and consumers in the country. To improve this traditional product as a value-added product, an investigation was conducted to elucidate the microbial consortium associated with curd using culturable techniques and the microbial load was quantified in the presence of prebiotics. Twenty six samples of curd were analyzed to isolate microorganisms. The two major LAB groups present in the samples were characterized as Lactobacillus and Streptococcus. LABs were further identified as Lactobacillus delbrueckii subsp. lactis, L. planatarum, L. helviticus, Lactobacillus delbrueckii subsp. bulgaricus and L. casei subsp casei, Streptococcus thermophiles and S. lactis. Saccharomyces cerevisiae, Micrococcus spp., and Bacillus spp. were also present in this microbial consortium The addition of two types of commercially available prebiotics improved the counts of Lactobacillus in curd samples, despite the difference in the prebiotic compounds.

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Elli, Marina, Maria Luisa Callegari, Susanna Ferrari, Elena Bessi, Daniela Cattivelli, Sara Soldi, Lorenzo Morelli, Nathalie Goupil Feuillerat, and Jean-Michel Antoine. "Survival of Yogurt Bacteria in the Human Gut." Applied and Environmental Microbiology 72, no. 7 (July 2006): 5113–17. http://dx.doi.org/10.1128/aem.02950-05.

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ABSTRACT 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.

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Gouesbet, Gwenola, Gwenael Jan, and Patrick Boyaval. "Two-Dimensional Electrophoresis Study of Lactobacillus delbrueckii subsp. bulgaricus Thermotolerance." Applied and Environmental Microbiology 68, no. 3 (March 2002): 1055–63. http://dx.doi.org/10.1128/aem.68.3.1055-1063.2002.

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ABSTRACT The response of Lactobacillus delbrueckii subsp. bulgaricus cells to heat stress was studied by use of a chemically defined medium. Two-dimensional electrophoresis (2-DE) analysis was used to correlate the kinetics of heat shock protein (HSP) induction with cell recovery from heat injury. We demonstrated that enhanced viability, observed after 10 min at 65°C, resulted from the overexpression of HSP and from mechanisms not linked to protein synthesis. In order to analyze the thermoadaptation mechanisms involved, thermoresistant variants were selected. These variants showed enhanced constitutive tolerance toward heat shock. However, contrary to the wild-type strain, these variants were poorly protected after osmotic or heat pretreatments. This result suggests that above a certain threshold, cells reach a maximum level of protection that cannot be easily exceeded. A comparison of protein patterns showed that the variants were able to induce more rapidly their adaptive mechanisms than the original strain. In particular, the variants were able to express constitutively more HSP, leading to the higher level of thermoprotection observed. This is the first report of the study by 2-DE of the heat stress response in L. delbrueckii subsp. bulgaricus.

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Sun, Z., X. Chen, J. Wang, W. Zhao, Y. Shao, Z. Guo, X. Zhang, et al. "Complete Genome Sequence of Lactobacillus delbrueckii subsp. bulgaricus Strain ND02." Journal of Bacteriology 193, no. 13 (April 22, 2011): 3426–27. http://dx.doi.org/10.1128/jb.05004-11.

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DE URRAZA, PATRICIO J., ANDREA GÓMEZ-ZAVAGLIA, MARIO E. LOZANO, VICTOR ROMANOWSKI, and GRACIELA L. DE ANTONI. "DNA fingerprinting of thermophilic lactic acid bacteria using repetitive sequence-based polymerase chain reaction." Journal of Dairy Research 67, no. 3 (August 2000): 381–92. http://dx.doi.org/10.1017/s002202990000426x.

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DNA fingerprints of lactic acid bacteria were generated by polymerase chain reaction using a primer based on the repetitive elements found in the genome of Streptococcus pneumoniae (BOX-PCR). The method made it possible to identify 37 isolates from raw milk, industrial starters and yogurt. Differentiation at species, subspecies and strain level was possible for Lactobacillus delbrueckii subsp. lactis, Lb. delbrueckii subsp bulgaricus and Str. thermophilus. BOX-PCR was also applied to studying the strain composition of a starter culture and the direct detection of strains in commercial fermented milk.

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., Kusmiati, Fifi Afiati, and Farha Elein Kukihi. "Exopolysaccharide (EPS) activity test of lactic acid bacteria (LAB) as immunomodulatory." Jurnal Ilmu Ternak dan Veteriner 21, no. 3 (September 26, 2017): 182. http://dx.doi.org/10.14334/jitv.v21i3.1414.

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<p>Immunomodulatory activity assay and characterization of exopolysaccharide (EPS) from Lactic Acid Bacteria (LAB) was done in Bogor. Bacteria used in this study was LAB strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Exopolysaccharide was extracted from L. delbrueckii subsp. bulgaricus and S. thermophilus then characterized with FT-IR spectrophotometer to determine the functional group. IR spectrum analysis using Fourier Transform-Infra Red (FT-IR) showed that EPS from both LAB isolates were carbohydrate compounds. Immunomodulatory activity in vivo from EPS was measured using phagocytic activity and phagocytic capacity macrophage cells from mice peritoneal cavity fluid. Exopolysaccharide were given orally to mice in concentrations of 100 μg/ml, 200 μg/ml and 300 μg/ml for 14 days then the mice were infected with Staphylococcus aureus. Result showed that EPS from both LAB isolate enhanced either phagocytic activity and phagocytic capacity macrophage cell from mice peritoneal fluid. EPS from L. delbrueckii subsp. bulgaricus concentration 300 μg/ml showed the highest phagocytic activity of macrophage cells and EPS from S. thermophilus concentration 300 μg/ml showed the highest phagocytic capacity. It is concluded that EPS potency tested as immunomodulatory derived from a culture of L. delbrueckii and S. thermophilus subsp.bulgaricus are able to increase the activity and phagocytosis murine peritoneal macrophages.</p>

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Lee, Ju-Hoon, Jamie S. Halgerson, Jeong-Hwan Kim, and Daniel J. O'Sullivan. "Comparative Sequence Analysis of Plasmids from Lactobacillus delbrueckii and Construction of a Shuttle Cloning Vector." Applied and Environmental Microbiology 73, no. 14 (May 25, 2007): 4417–24. http://dx.doi.org/10.1128/aem.00099-07.

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ABSTRACT While plasmids are very commonly associated with the majority of the lactic acid bacteria, they are only very rarely associated with Lactobacillus delbrueckii, with only four characterized to date. In this study, the complete sequence of a native plasmid, pDOJ1, from a strain of Lactobacillus delbrueckii subsp. bulgaricus was determined. It consisted of a circular DNA molecule of 6,220 bp with a G+C content of 44.6% and a characteristic ori and encoded six open reading frames (ORFs), of which functions could be predicted for three—a mobilization (Mob) protein, a transposase, and a fused primase-helicase replication protein. Comparative analysis of pDOJ1 and the other available L. delbrueckii plasmids (pLBB1, pJBL2, pN42, and pLL1212) revealed a very similar organization and amino acid identities between 85 and 98% for the putative proteins of all six predicted ORFs from pDOJ1, reflecting a common origin for L. delbrueckii plasmids. Analysis of the fused primase-helicase replication gene found a similar fused organization only in the theta replicating group B plasmids from Streptococcus thermophilus. This observation and the ability of the replicon to function in S. thermophilus support the idea that the origin of plasmids in L. delbrueckii was likely from S. thermophilus. This may reflect the close association of these two species in dairy fermentations, particularly yogurt production. As no vector based on plasmid replicons from L. delbrueckii has previously been constructed, an Escherichia coli-L. delbrueckii shuttle cloning vector, pDOJ4, was constructed from pDOJ1, the p15A ori, the chloramphenicol resistance gene of pCI372, and the lacZ polylinker from pUC18. This cloning vector was successfully introduced into E. coli, L. delbrueckii subsp. bulgaricus, S. thermophilus, and Lactococcus lactis. This shuttle cloning vector provides a new tool for molecular analysis of Lactobacillus delbrueckii and other lactic acid bacteria.

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Chervaux, Christian, S. Dusko Ehrlich, and Emmanuelle Maguin. "Physiological Study of Lactobacillus delbrueckii subsp. bulgaricus Strains in a Novel Chemically Defined Medium." Applied and Environmental Microbiology 66, no. 12 (December 1, 2000): 5306–11. http://dx.doi.org/10.1128/aem.66.12.5306-5311.2000.

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ABSTRACT We developed a chemically defined medium called milieu proche du lait (MPL), in which 22 Lactobacillus delbrueckii subsp.bulgaricus (L. bulgaricus) strains exhibited growth rates ranging from 0.55 to 1 h−1. MPL can also be used for cultivation of other lactobacilli and Streptococcus thermophilus. The growth characteristics of L. bulgaricus in MPL containing different carbon sources were determined, including an initial characterization of the phosphotransferase system transporters involved. For the 22 tested strains, growth on lactose was faster than on glucose, mannose, and fructose. Lactose concentrations below 0.4% were limiting for growth. We isolated 2-deoxyglucose-resistant mutants from strains CNRZ397 and ATCC 11842. CNRZ397-derived mutants were all deficient for glucose, fructose, and mannose utilization, indicating that these three sugars are probably transported via a unique mannose-specific-enzyme-II-like transporter. In contrast, mutants of ATCC 11842 exhibited diverse phenotypes, suggesting that multiple transporters may exist in that strain. We also developed a protein labeling method and verified that exopolysaccharide production and phage infection can occur in MPL. The MPL medium should thus be useful in conducting physiological studies ofL. bulgaricus and other lactic acid bacteria under well controlled nutritional conditions.

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Pham, Mai-Lan, Anh-Minh Tran, Suwapat Kittibunchakul, Tien-Thanh Nguyen, Geir Mathiesen, and Thu-Ha Nguyen. "Immobilization of β-Galactosidases on the Lactobacillus Cell Surface Using the Peptidoglycan-Binding Motif LysM." Catalysts 9, no. 5 (May 12, 2019): 443. http://dx.doi.org/10.3390/catal9050443.

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Lysin motif (LysM) domains are found in many bacterial peptidoglycan hydrolases. They can bind non-covalently to peptidoglycan and have been employed to display heterologous proteins on the bacterial cell surface. In this study, we aimed to use a single LysM domain derived from a putative extracellular transglycosylase Lp_3014 of Lactobacillus plantarum WCFS1 to display two different lactobacillal β-galactosidases, the heterodimeric LacLM-type from Lactobacillus reuteri and the homodimeric LacZ-type from Lactobacillus delbrueckii subsp. bulgaricus, on the cell surface of different Lactobacillus spp. The β-galactosidases were fused with the LysM domain and the fusion proteins, LysM-LacLMLreu and LysM-LacZLbul, were successfully expressed in Escherichia coli and subsequently displayed on the cell surface of L. plantarum WCFS1. β-Galactosidase activities obtained for L. plantarum displaying cells were 179 and 1153 U per g dry cell weight, or the amounts of active surface-anchored β-galactosidase were 0.99 and 4.61 mg per g dry cell weight for LysM-LacLMLreu and LysM-LacZLbul, respectively. LysM-LacZLbul was also displayed on the cell surface of other Lactobacillus spp. including L. delbrueckii subsp. bulgaricus, L. casei and L. helveticus, however L. plantarum is shown to be the best among Lactobacillus spp. tested for surface display of fusion LysM-LacZLbul, both with respect to the immobilization yield as well as the amount of active surface-anchored enzyme. The immobilized fusion LysM-β-galactosidases are catalytically efficient and can be reused for several repeated rounds of lactose conversion. This approach, with the β-galactosidases being displayed on the cell surface of non-genetically modified food-grade organisms, shows potential for applications of these immobilized enzymes in the synthesis of prebiotic galacto-oligosaccharides.

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Grahek-Ogden, Danica, Karl Eckner, Georg Kapperud, Jørgen Lassen, Judith Narvhus, Truls Nesbakken, Lucy Robertson, et al. "Risk Assessment of Lactobacillus delbrueckii subsp. bulgaricus Used as "Other Substances"." European Journal of Nutrition & Food Safety 8, no. 4 (October 29, 2018): 341–42. http://dx.doi.org/10.9734/ejnfs/2018/44962.

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KUDOH, Yasufumi, Shigeki MATSUDA, Keiji IGOSHI, and Tomoyuki OKI. "Antioxidative Peptide from Milk Fermented with Lactobacillus delbrueckii subsp. bulgaricus IFO13953." NIPPON SHOKUHIN KAGAKU KOGAKU KAISHI 48, no. 1 (2001): 44–50. http://dx.doi.org/10.3136/nskkk.48.44.

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Le Bras, Gisèle, Françoise De La Torre, Pavel Branny, and Jean-Renaud Garel. "Enzymatic and genetic régulation of glycolysis in Lactobacillus delbrueckii subsp. bulgaricus." Le Lait 78, no. 1 (1998): 85–90. http://dx.doi.org/10.1051/lait:1998111.

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Bockelmann, Wilhelm, Yvonne Schulz, and Michael Teuber. "Purification and characterization of an aminopeptidase from Lactobacillus delbrueckii subsp. bulgaricus." International Dairy Journal 2, no. 2 (January 1992): 95–107. http://dx.doi.org/10.1016/0958-6946(92)90003-5.

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Wohlrab, Yvonne, and Wilhelm Bockelmann. "Purification and characterization of a dipeptidase from Lactobacillus delbrueckii subsp. bulgaricus." International Dairy Journal 2, no. 6 (January 1992): 345–61. http://dx.doi.org/10.1016/0958-6946(92)90026-i.

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Somkuti, George A., Mary E. Dominiecki, and Dennis H. Steinberg. "Permeabilization of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus with Ethanol." Current Microbiology 36, no. 4 (April 1, 1998): 202–6. http://dx.doi.org/10.1007/s002849900294.

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Arioli, Stefania, Giulia Della Scala, Maria Chiara Remagni, Milda Stuknyte, Stefano Colombo, Simone Guglielmetti, Ivano De Noni, Enzio Ragg, and Diego Mora. "Streptococcus thermophilus urease activity boosts Lactobacillus delbrueckii subsp. bulgaricus homolactic fermentation." International Journal of Food Microbiology 247 (April 2017): 55–64. http://dx.doi.org/10.1016/j.ijfoodmicro.2016.01.006.

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Do Carmo, A., D. da Silva, M. De Oliveira, A. Borges, A. De Carvalho, and C. De Moraes. "Genes involved in protein metabolism of the probiotic lactic acid bacterium Lactobacillus delbrueckii UFV H2b20." Beneficial Microbes 2, no. 3 (September 1, 2011): 209–20. http://dx.doi.org/10.3920/bm2011.0025.

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Abstract:

A basic requirement for the prediction of the potential use of lactic acid bacteria (LAB) in the dairy industry is the identification of specific genes involved in flavour-forming pathways. The probiotic Lactobacillus delbrueckii UFV H2b20 was submitted to a genetic characterisation and phylogenetic analysis of genes involved in protein catabolism. Eight genes belonging to this system were identified, which possess a closely phylogenetic relationship to NCFM strains representative, as it was demonstrated for oppC and oppBII, encoding oligopeptide transport system components. PepC, PepN, and PepX might be essential for growth of LAB, probiotic or not, since the correspondent genes are always present, including in L. delbrueckii UFV H2b20 genome. For pepX gene, a probable link between carbohydrate catabolism and PepX expression may exists, where it is regulated by PepR1/CcpA-like, a common feature between Lactobacillus strains and also in L. delbrueckii UFV H2b20. The well conserved evolutionary history of the ilvE gene is evidence that the pathways leading to branched-chain amino acid degradation, such as isoleucine and valine, are similar among L. delbrueckii subsp. bulgaricus strains and L. delbrueckii UFV H2b20. Thus, the involvement of succinate in flavour formation can be attributed to IlvE activity. The presence of aminopeptidase G in L. delbrueckii UFV H2b20 genome, which is absent in several strains, might improve the proteolytic activity and effectiveness. The nucleotide sequence encoding PepG revealed that it is a cysteine endopeptidase, belonging to Peptidase C1 superfamily; sequence analysis showed 99% identity with L. delbrueckii subsp. bulgaricus ATCC 11842 pepG, whereas protein sequence analysis revealed 100% similarity with PepG from the same organism. The present study proposes a schematic model to explain how the proteolytic system of the probiotic L. delbrueckii UFV H2b20 works, based on the components identified so far.

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Dimitrova, Milena, Galin Ivanov, Kiril Mihalev, Alexander Slavchev, Ivelina Ivanova, and Radka Vlaseva. "Investigation of antimicrobial activity of polyphenol-enriched extracts against probiotic lactic acid bacteria." Food Science and Applied Biotechnology 2, no. 1 (March 18, 2019): 67. http://dx.doi.org/10.30721/fsab2019.v2.i1.57.

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Abstract:

The antimicrobial activity of polyphenol-enriched extracts from industrial plant by-products (strawberry and bilberry press residues and distilled rose petals) against probiotic lactic acid bacteria (Lactobacillus delbrueckii subsp. bulgaricus – S10 and S19; Lactobacillus rhamnosus – YW and S25; Lactobacillus gasseri – S20; Streptococcus thermophilus – S13 and S32) was investigated. The minimum inhibitory concentration (MIC) in most strains tested was found to be relatively high (from 6.25 mg.mL-1 to 12.50 mg.mL-1). The maximum concentration of polyphenols without inhibitory effect (MCWI) ranges from 0.390mg.mL-1 to 0.781mg.mL-1. The results obtained in the present study showed that among the tested lactic acid bacteria Lactobacillus delbrueckii subsp. bulgaricus – S19, Lactobacillus rhamnosus – YW and Streptococcus thermophilus – S13 had the best growth characteristics in polyphenol-enriched culture medium. These strains had the highest MIC and MCWI values and could be used as starter cultures for polyphenol-fortified fermented milks. Practical applications: The use of polyphenol-enriched extracts from industrial plant by-products (waste) – distilled rose petals (by-products of rose oil production) and strawberry and bilberry press residues (by-products of fruit juice production) contribute for improving the economic effect and for solving environmental problems in food industry. Development of functional fermented milks with combination of probiotic starter cultures and polyphenol extracts is current and perspective direction of food industry.

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Journal articles on the topic 'Lactobacillus delbrueckii subsp. bulgaricus'

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