Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A bacteriocin (Reutericin 6) produced by Lactobacillus reuteri LA6, was purified by hydrophobic chromatography from the modified MRS broth (D'-MRS) with 6180-fold increase in specific activity with 14% recovery. The molecular weight of reutericin 6 was determined to be 2.7 kDa by SDS-PAGE and ESI-MS. By amino acid analysis, reutericin 6 comprised of 67% hydrophobic and polar neutral amino acids. Lanthionine was not detected. The lytic activity against Lactobacillus delbrueckii subsp. bulgaricus JCM 1002T and N1A1 B6 was detected by the decrease of both turbidity and the number of viable cells, and by leaking of beta-galactosidase.
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PMID:Production, purification and characterization of reutericin 6, a bacteriocin with lytic activity produced by Lactobacillus reuteri LA6. 903 61

Beta-galactosidase activity was studied as a possible cause of the low milk acidification ability observed in Lactobacillus reuteri NRRL 14171. Enzymatic activity was determined in MRS broth supplemented with either glucose or lactose and milk at the middle and final stage of the exponential phase, as well as at the stationary phase. Results were compared with beta-galactosidase activity in Lactobacillus casei NRRL-B1922, a strain that shows the milk acidification ability. The effects of the types of carbon and nitrogen sources were established by comparison of growth parameters (higher maximum cell concentration and specific growth rate) in broth culture and skim milk supplemented with 2% glucose or 1% casein peptone. In milk, L. reuteri showed higher beta-galactosidase activity in all growth phases compared with L. casei. Greater cell concentration maxima, specific growth rates, and acidification abilities were observed in L. reuteri when it was cultured in milk supplemented with 1% casein peptone compared with non-supplemented milk cultures. Results suggest that the poor milk acidification ability observed in L. reuteri may be more related to a weak proteolytic system than to deficient beta-galactosidase activity.
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PMID:Lactobacillus reuteri beta-galactosidase activity and low milk acidification ability. 1592 Jun 24

Bacteriophage ch2, a virulent bacteriophage of Lactobacillus bulgaricus CH2, was characterized according to its morphology, genome size, structural proteins, and growth kinetics. Electron micrographs revealed that bacteriophage ch2 has an icosahedral head of 50-nm diameter and a long tail of 170 nm. Its genome is linear and 35 kilobases in length, and its structural proteins consist of two major and eight minor proteins. One-step growth kinetics of bacteriophage ch2 under optimal conditions (45 degrees C in MRS medium [Oxoid Ltd.]) showed that the latent time was 40 min, the rise period was 15 min, and the burst size was 130 bacteriophages per cell. To monitor the effects of bacteriophage infection on host growth and beta-galactosidase production, the absorbance of the culture and the beta-galactosidase activity were followed during the infection cycle. Before lysis the infected culture continued to grow and produce beta-galactosidase at the same rate as the uninfected culture.
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PMID:Characterization of Lactobacillus bulgaricus Bacteriophage ch2. 1634 27

Lactobacillus strains from traditional African fermented milk products, as well as human intestinal isolates were identified and investigated in vitro for their technological and functional characteristics as potential new probiotic strains. To test survival under gastrointestinal conditions, first the protective effect of milk and the effects of medium composition, lysozyme, pepsin, and pH of the medium on bacterial viability were assessed in vitro using the Plackett-Burman statistical model and the commercially used L. johnsonii LA1 probiotic strain. The use of either an artificial gastric electrolyte solution or MRS did not play a significant role in the viability of the cultures, while lysozyme, acidic conditions (pH 2.5), pepsin and the presence of milk significantly influenced the survival of the strain. Therefore, these parameters were selected as important test variables in a model stomach passage survival trial. Five strains identified as L. plantarum and two identified as L. johnsonii showed good survival under simulated gastrointestinal conditions. These selected strains also showed antimicrobial activity, probably due to production of organic acids. All strains exhibited bile salt hydrolase activity, while only the L. plantarum strains showed beta-galactosidase activity.
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PMID:Lactobacillus spp. with in vitro probiotic properties from human faeces and traditional fermented products. 1650 61

Four lactobacilli strains (Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacilus casei and Lactobacillus reuteri) were grown in MRS broth and three lactococci strains (Streptococcus thermophilus, Lactococcus lactis subsp. Lactis and Lactococcus lactis subsp. lactis biovar. diacetilactis) were grown in M17 broth. L. reuteri and S. thermophilus were chosen on the basis of the best mean beta-galactosidase activity of 10.44 and 10.01 U/ml respectively, for further studies on permeate-based medium. The maximum production of beta-galactosidase by L. reuteri was achieved at lactose concentration of 6%, initial pH 5.0-7.5, ammonium phosphate as nitrogen source at a concentration of 0.66 g N/L and incubation temperature at 30 degrees C/24 hrs to give 6.31 U/ml. While in case of S. thermophilus, maximum beta-galactosidase production was achieved at 10% lactose concentration of permeate medium, supplemented with phosphate buffer ratio of 0.5:0.5 (KH2PO4:K2HPO4, g/L), at initial pH 6.0-6.5, ammonium phosphate (0.66g N/L) as nitrogen source and incubation temperature 35 degrees C for 24 hrs to give 7.85 U/ml.
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PMID:Utilization of UF-permeate for production of beta-galactosidase by lactic acid bacteria. 2190 31