• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.479-485
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• 2015

This study was performed to investigate the sedative-hypnotic activity of ${\gamma}$-aminobutyric acid (GABA)-enriched fermented marine organisms (FMO), including sea tangle (FST) and oyster (FO) by Lactobacillus brevis BJ20 (L. brevis BJ20). FST and FO were tested for their binding activity of the $GABA_A$-benzodiazepine and 5-$HT_{2C}$ receptors, which are well-known molecular targets for sleep aids. We also measured the sleep latency and sleep duration during pentobarbital-induced sleep in mice after oral administration of FST and FO. In $GABA_A$ and 5-$HT_{2C}$ receptor binding assays, FST displayed an effective concentration-dependent binding affinity to $GABA_A$ receptor, similar to the binding affinity to 5-$HT_{2C}$ receptor. FO exhibited higher affinity to 5-$HT_{2C}$ receptor, compared with the $GABA_A$ receptor. The oral administration of FST and FO produced a dose-dependent decrease in sleep latency and increase in sleep duration in pentobarbital-induced hypnosis. The data demonstrate that FST and FO possess sedativehypnotic activity possibly by modulating $GABA_A$ and 5-$HT_{2C}$ receptors. We propose that FST and FO might be effective agents for treatment of insomnia.

• Food Science and Preservation
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• v.6 no.4
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• pp.448-455
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• 1999

The starters, 0.3% of Leuconostoc mesenteroides, Lactobacillus brevis and Lactobacillus fermentum, were added in radish juice to process the radish juice by single and mixed cultures. The radish Juice was fermented for 7 days at 25$^{\circ}C$, 20 days at 15$^{\circ}C$, and 36 days at 5$^{\circ}C$. When fermented at 25$^{\circ}C$, the number of lactic acid bacteria in the juice made with mixed culture was higher than that of the single culture. But, juice fermented at low temperatures (15∼5$^{\circ}C$), the addition of starters was not effective, although there were some differences by inoculation strains. Although there was a little differences by inoculation strains, the content of nonvolatile organic acid and L-ascorbic acid were found more in the juice inoculated with lactic acid bacteria than the juice not inoculated. When the single and mixed cultures at the optimal maturity were tested, the significant difference was found at 5% level except the yeasty and moldy smell and the unripe taste. According to the preference test, the mixed-cultured radish juice incubated at 25$^{\circ}C$with Lactobacillus brevis and Leuconostoc mesenteroides were evaluated superior to commercial Dongchimi. As a result, taste and quality of radish juice was improved by addition of starters.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.298-303
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• 2021

Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)-Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus-to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/μl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/μl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.

• Journal of Mushroom
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• v.19 no.3
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• pp.191-199
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• 2021

This study was conducted to improve the useful components and biological activity of Lentinula edodes fermented by lactic acid bacteria (LAB). Three LAB strains (Lactobacillus brevis KCCM 11904, L. plantarum KCCM 354469, and L. fermentum KCCM 12116) were inoculated and used for L. edodes hot water extract (10%, 20%, 30%) fermentation. LAB fermentation of L. edodes hot water extracts decreased pH and thus were more acidic than non-fermented L. edodes hot water extract. β-glucan and ergothioneine contents were increased by L. edodes in a concentration-dependent manner. The ergothioneine and β-glucan contents were highest in fermented with 30% L. edodes hot water extract fermented by L. plantarum and L. brevis (40.48 mg/100 g and 13.94%, respectively). The hepato-protective effect of fermented L. edodes hot water extracts by the three LAB were tested using Sprague-Dawley rat primary hepatocytes. In primary hepatocytes obtained following liver injury induced by acetaminophen, fermented L. edodes hot water extracts by the three LAB showed protective effects, as evident by reduction of the aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase liver markers. The collective results indicate that the fermented L. edodes hot water extracts obtained using LAB are potentially valuable in preventing or treating liver disease.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.631-636
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• 2002

Lethality of high intensity light pulse on the pre-determined microbial populations has been investigated. Prior to the treatment, Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus pentosaceus were cultivated separately onto the surface of Lactobacilli MRS agar. Pre-determined microbial populations were applied to the test media and these sample were exposed to high intense light source with an exposure time ranging from 1 to $2500\;{\mu}s$. Results showed that at least 200 light pulses of $1\;{\mu}s$ duration were required to reduce L. Plantarum cells by 90% at 25 kV, the greater the number of light pulses, the larger the reduction in viable cell numbers. Viable cells of L. plantarum and the others were reduced by more than 5 and 6 log cycles at the upper exposure level of $750\;{\mu}s$, respectively. These study shows that pulsed light emissions can significantly reduce populations of lactic acid bacteria on exposed surface with exposure times. Killing efficiency for L. plantarum significantly increased with decreasing the distance between the lamp and the surface of samples.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.155-161
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• 2022

The aim of this study was to investigate the effect of isolated lactic acid bacteria (LAB) on the quality of high moisture rye silage. Rye forage (Secale cereale L.) was harvested at the heading stage (27.3% of dry matter (DM)) and cut into approximately 3-5 cm lengths. Then, the forage divided into 4 treatments with different inoculants: 1) No additives (CON); 2) Lactobacillus brevis strain 100D8 at a 1.2 × 10⁵ colony-forming unit (cfu)/g of fresh forage (LBR); 3) Leuconostoc holzapfelii strain 5H4 at a 1.0 × 10⁵ cfu/g of fresh forage (LHO); and 4) Mixture of LBR and LHO (1:1 ratio) applied at a 1.0 × 10⁵ cfu/g of fresh forage (MIX). About 3 kg of forage from each treatment was ensiled into a 20 L mini-bucket silo in quadruplicate for 100 days. After silo opening, silage was collected for analyses of chemical compositions, in vitro nutrient digestibilities, fermentation characteristics, and microbial enumerations. The CON silage had the highest concentrations of neutral detergent fiber and acid detergent fiber (p = 0.006; p = 0.008) and a lowest in vitro DM digestibility (p < 0.001). The pH was highest in CON silage, while lowest in LBR and MIX silages (p < 0.001). The concentrations of ammonia-N, lactate, and acetate were highest in LBR silage (p = 0.008; p < 0.001; p < 0.001). Propionate and butyrate concentrations were highest in CON silage (p = 0.004; p < 0.001). The LAB and yeast counts were higher in CON and LHO silages compare to LBR and MIX silages (p < 0.001). However, the mold did not detect in all treatments. Therefore, this study could conclude that L. brevis 100D8 and Leu. holzapfelii strain 5H4 can improve the digestibility and anti-fungal activity of high moisture rye silage.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.269-277
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• 2003

This study was carried out to evaluate the safety of Korean human milk. The microorganisms were identified from human milk of 149 healthy mothers by two collection methods, hand and pump expression. The means of total bacterial counts were 2.33x10$^4$ cfu/mL on the samples collected by the pump expression and 7.83xl0$^3$ cfu/mL on those collected by the hand expression. Therefore, the total bacterial counts of pump expression samples was 9.80xl0$^2$∼3.06x10$^4$ cfu/mL more than that of hand expression samples. The coliform counts of pump expression was 9.36xl0$^3$∼8.57xl0$^4$ cfu/mL more than that of hand expression. However, there was any significant differences of the lactic acid bacterial counts between the two samples collected by each methods. 100 strains of 5 patterns of total bacterial counts were isolated based on the morphology of colony in the standard plate count agar. 13 species were identified among the isolated strains. The dominant species in Korean human milk were Staphylococcus which 7 subspecies identified(81% in the rate of total bacteria, 1.07x10$^4$ cfu/mL). Other species identified were Micrococcus, Bacillus, Providencia, Pseudomonas, Yersinia and Acinetobacter. 36 strains of 6 patterns of lactic acid bacterial counts were isolated based on morphology of colony in the BCP agar. 7 species were identified among the isolated strains. The dominant species of lactic acid bacteria in Korean human milk were Lactobacillus brevis(50.9% in the rate of lactic acid bacteria, 4.72xl0$^4$ cfu/mL). Others species identified(49.1% lactic acid bacteria) were Lactobacillus curvatus, Lactobacillus delbrueckii subsp. lactis, Lactobacillus acidophilus, Leuconostic lactis and Streptococcus salivarius subsp. thermophilus.

• Journal of Dairy Science and Biotechnology
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• v.22 no.2
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• pp.91-97
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• 2004

The antioxidative ability on the basis of reduced glutathione sulphydryl(GSH) level, the inhibition activities of linoleic acid peroxidation of cell free extract of Lactobacillus spp. and Bacillus spp. have been determined; Lactobacillus casei CU4114 contained the highest level of GSH among the probiotic strains with 25.15 ${\mu}$mole/g. Significantly high level of GSH occured in the intracellular cell free extract of Lactobacillus rhamnosus CU4201, Lactobacillus plantarum CU4203. The antioxidant activity and inhibition of linoleic acid peroxidation of cell free extract of Lactobacillus spp. and Bacillus spp. by thiobarbituric acid(TBA) assay have been shown to be significantly differed depending on the strains(P>0.01). Intracellular cell free extracts of L. acidophilus CU4111, L. casei CU4114, and strains of Bacillus coacillus revealed a significantly intensive inhibitory activity in the linoleic acid peroxidation reactions. Spearmans' rank correlation between inhibitory activity on linoleic acid peroxidation and cellular GSH levels of Lactobacillus spp. was analysed and the correlation quotient was 0.65 which means a significant positive correlation.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.560-566
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• 2001

This study was conducted to investigate the effects of solvent extracts from medicinal plants on the fermentation of kimchi. Five microorganisms related to kimchi fermentation were selected and the antimicrobial activities of solvent fractions from medicinal plants were investigated. The chloroform fraction from the methanol extract of dandelion (Taraxacum platycarpum D.) exhibited inhibitory activity against five strains such as Lactobacilli plantarum, Lactobacilli brevis, Leuconostoc mesenteroides, Enterococcus faecalis and Saccharomyces cerevisiae. The chloroform fraction from the methanol extract of Dandelion inhibited the growth of E. faecalis and Leu. mesenteroides at the concentration of 80 mg/mL. Scanning electron micrographs of Leu. mesenteroides and E. faecalis treated with chloroform fraction 80 mg/mL exhibited morphological changes, including irregularly contracted cell surface.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.375-382
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• 2010

The available techniques for heterologous protein secretion in Lactobacillus strains are limited. The aim of the present study was to develop an efficient protein-secretion system using recombinant lactobacilli for various applications such as live delivery of biotherapeutics. For the construction of expression vectors, the Lactobacillus brevis slpA promoter, Lactobacillus casei prtP signal sequence, and mouse IL-10 sequences were used as a model system. Interestingly, the slpA promoter exhibited strong activity in L. casei, contrary to previous observations. In order to stabilize replication of the plasmid in E. coli, a removable terminator sequence was built into the promoter region. For the improvement of secretion efficiency, a DTNSD oligopeptide was added to the cleavage site of signal peptidase. The resulting plasmids provided remarkably efficient IL-10 secretion. Accumulation of the protein in the culture supernatant varied widely according to the pH conditions. By analysis of the secreted protein, formation of homodimers, and biological activity, IL-10 was confirmed to be functional. The presently constructed plasmids could be useful tools for heterologous protein secretion in L. casei.