ABSTRACT
The probiotic properties of ten lactic acid bacteria and antioxidant and α-glucosidase inhibitory activities of the exopolysaccharide (EPS) of the selected strain were investigated in this study. Levilactobacillus brevis L010 was one of the most active strains across all the in vitro tests. The cell-free supernatant (50 g/l) of L. brevis L010 showed high levels of both α-glucosidase inhibitory activity (98.73 ± 1.32%) and 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (32.29 ± 3.86%). The EPS isolated from cell-free supernatant of L. brevis L010 showed 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activity (80.27 ± 2.51%) at 80 g/l, DPPH radical-scavenging activity (38.19 ± 9.61%) at 40 g/l, and ferric reducing antioxidant power (17.35 ± 0.20 mg/l) at 80 g/l. Further, EPS exhibited inhibitory activities against α-glucosidase at different substrate concentrations. Kinetic analysis suggests that the mode of inhibition was competitive, with a kinetic constant of Km = 2.87 ± 0.88 mM and Vmax = 0.39 ± 0.06 µmole/min. It was concluded that the EPS might be one of the plausible candidates for possible antioxidant and α-glucosidase activities of the L. brevis L010 strain.
Subject(s)
Levilactobacillus brevis , Probiotics , Antioxidants/pharmacology , Antioxidants/chemistry , alpha-Glucosidases/metabolism , KineticsABSTRACT
In this study, lactic acid bacteria strains (LABs) were isolated from Korean traditional fermented food and examined as potential probiotics using in vitro methods. Ten LAB strains survived in de Man, Rogosa and Sharpe broth adjusted to pH 2.5 were tested for resistance to acidic conditions and bile, antimicrobial activity, and α-glucosidase inhibitory activity. Among them, strain MBEL1397 showed antimicrobial activity against Bacillus cereus and exhibited survival rates of over 97% in acidic and bile conditions. The α-glucosidase inhibitory activity was 3.91 ± 0.25%, corresponding to approximately 2.3 times higher than that of acarbose. MBEL1397 was susceptible to ampicillin, erythromycin, and penicillin G and identified as Lactobacillus sakei. It was deposited to Korean Collection for Type Culture (KCTC) as KCTC14037BP. In conclusion, these results demonstrate that L. sakei MBEL1397 might be prominent probiotics with potential hypoglycemic effects.
ABSTRACT
Lactobacillus sakei MBEL1397(=KCTC14037BP) was isolated from kimchi, a traditional Korean fermented food, in Gangwon province, Republic of Korea. MBEL1397 is an acid-tolerant strain with antimicrobial activity and α-glucosidase inhibitory activity, which might be preliminary indications of its probiotic properties. Complete genome sequencing of L. sakei MBEL1397 was performed using the PacBio RSII platform. MBEL1397 has a 1,994,569 bp circular chromosome with 41.04% G+C content. The genome includes 1,946 protein-coding genes, 66 transfer RNA genes, and 21 ribosomal RNA genes. The BioProject has been deposited at DDBJ/EMBL/GenBank. The GenBank accession numbers are PRJNA598112 for the BioProject, SAMN13698554 for the BioSample, and CP048116 for the chromosome.
ABSTRACT
The entire nucleotide sequence of the HIS3 gene encoding imidazoleglycerol phosphate dehydratase (IGPD) in yeast Candida milleri CBS 8195 was determined. Sequence analysis revealed an open-reading frame of C. milleri HIS3 that spans 678 bp, encodes 226 amino acids, and shares 80.5% amino acid identity to Torulaspora delbrueckii IGPD, followed by that to Saccharomyces cerevisiae (79.6%). The cloned HIS3 gene complemented a his3 mutation in S. cerevisiae, suggesting that it encodes a functional IGPD in C. milleri CBS 8195. A new auxotrophic marker is now available for acid-tolerant yeast C. milleri.
