• Journal of Life Science
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• v.34 no.7
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• pp.465-475
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• 2024

Lactiplantibacillus plantarum K9 is a probiotic strain that can be utilized from various bioactive substances isolated from Protaetia brevitarsis seulensis larvae. In this study, a genetic analysis of L. plantarum K9 revealed the existence of a bacterial chromosome and three plasmids. The glycolysis pathway and pentose phosphate pathway were examined for their normal functioning via an analysis of the core metabolic pathways of L. plantarum K9. Since the key enzymes, fluctose-1,6-bisphospatase (EC: 3.1.3.11) and 6-phosphogluconate dehydratase (EC: 4.2.1.12)/2-keto-deoxy-6-phosphogluconate (KDPG) aldolase (EC: 4.2.1.55), of gluconeogenesis and the ED pathway were not identified from the L. plantarum K9 genome, we suggest that gluconeogenesis and the ED pathway are not performed in L. plantarum K9. Additionally, while some enzymes, related to fumarate and malate biosyntheses, involved in the TCA cycle were identified from L. plantarum K9, the enzymes associated with the remaining TCA cycle were absent, indicating that the TCA cycle cannot proceed. Meanwhile, based on our findings, we propose that the oxidative electron transport system performs class IIB-type (bd-type) electron transfer. In summary, we assert that L. plantarum K9 performs homolactic fermentation, executes gluconeogenesis and the pentose phosphate pathway, and carries out energy metabolism through the class IIB-type oxidative electron transport system. Therefore, we suggest that L. plantarum K9 has relatively high lactic acid production, and that it has excellent antibacterial activity, as a result, compared to other lactic acid bacterial strains. Moreover, we speculate that L. plantarum K9 has an oxidative electron transport capability, indicating that it is highly resistant to oxygen and suggesting that it has fine cultivation characteristics, which collectively make it highly suitable for use as a probiotic.

• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.24-32
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• 2009

The KNUC25 strain isolated from over-fermented whole Chinese cabbage kimchi was examined for its physiological characteristics using API 50 CHL system assay and identified as Lactobacillus paraplantarum by analysis of whole-cell protein SDS-PAGE pattern assay and similarity of 16S rDNA sequence. L. paraplantarum KNUC25 had a broad antimicrobial activity spectrum from Gram positive to Gram negative bacteria. Scanning electron micrograph analysis showed that KNUC25 might attack to cell surface of indicator cells and destruction can lead to inhibition of the cell growth. The antimicrobial substance of the KNUC25 strain was stable to various degrading enzymes and at high temperature and not a plasmid-born matter. Resistance to proteolytic enzymes showed that an antimicrobial activity of KNUC25 might not be caused by proteinous substance. Maximum production of antimicrobial substance was the exponential growth phase at $30^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.943-946
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• 2017

Although the genus Leuconostoc, generally found in various fermented foods, has often been suggested to be a novel probiotic for food fermentation and health promotion, the strains in this genus showed low acid tolerance and low osmotic stress resistance activities, which are required for survival during food fermentation events. Recently, a novel species of Weissella, W. jogaejeotgali $FOL01^T$ (= KCCM 43128 = JCM 30580), was isolated from Korean fermented clams. To determine the genomic features of this new species, its genome was completely sequenced and analyzed. The genome consists of a circular chromosome of 2,114,163 bp of DNA with a G+C content of 38.8%, and the plasmid pFOL01 consists of 35,382 bp of DNA with a G+C content of 39.1%. The genome analysis showed its potential for use in food fermentation and osmotic stress resistance abilities for processing in food industries. In addition, this strain was predicted to have acid tolerance and adhesion to the mucosal layer for survival and colonization in the gut. Subsequent experiments substantiated these abilities, suggesting that W. jogaejeotgali may have probiotic potential and a high survival rate during food fermentation. Therefore, it may be suitable as a novel probiotic strain for various applications in food industries.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.389-398
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• 2009

Development of expression vectors is important for the basic and applied researches on kimchi LAB (lactic acid bacteria). An expression vector, pSJE6c was constructed by inserting P6C promoter sequence from Lactococcus lactis into pSJE, a shuttle vector for E. coli and Leuconostoc species. To test the efficiency of pSJE6c, aga ($\alpha$-galactosidase) and lacZ ($\beta$-galactosidase) genes were expressed in Lactobacillus brevis 2.14. Compared to the pSJE, expression levels of both genes were increased, indicating P6C promoter was better than indigenous promoters. Enzyme activities of L. brevis cells harboring pSJE6caga (pSJE6c with aga) or pSJE6Z (pSJE6c with lacZ) were 1.5-2 fold higher than those with pSJEaga (pSJE with aga) or pSJEZ (pSJE with lacZ). More RNA transcripts were detected in cells harboring pSJE6c based recombinant plasmid. The results indicated that heterologous gene expressions in kimchi LAB could be improved significantly by use of efficient expression vectors.

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.160-170
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• 2019

The lactic acid bacteria species Lactobacillus plantarum (L. plantarum) has been used extensively for vaccine delivery. Considering to the critical role of dendritic cells in stimulating host immune response, in this study, we constructed a novel CD11c-targeting L. plantarum strain with surface-displayed variable fragments of anti-CD11c, single-chain antibody (scFv-CD11c). The newly designed L. plantarum strain, named 409-aCD11c, could adhere and invade more efficiently to bone marrow-derived DCs (BMDCs) in vitro due to the specific interaction between scFv-CD11c and CD11c located on the surface of BMDCs. After incubation with BMDCs, the 409-aCD11c strain harboring a eukaryotic vector pValac-GFP could lead to more efficient expression of GFP compared with wild-type strains shown by flow cytometry analysis, indicating the enhanced translocation of pValac-GFP from L. plantarum to BMDCs. Similar results were also observed in an in vivo study, which showed that oral administration resulted in efficient expression of GFP in both Peyer's patches (PP) and mesenteric lymph nodes (MLNs) within 7 days after the last administration. In addition, the CD11c-targeting strain significantly promoted the differentiation and maturation of DCs, the differentiation of $IL-4^+$ and $IL-17A^+$ T helper (Th) cells in MLNs, as well as production of $B220^+$ $IgA^+$ B cells in the PP. In conclusion, this study developed a novel DC-targeting L. plantarum strain which could increase the ability to deliver eukaryotic expression plasmid to host cells, indicating a promising approach for vaccine study.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.1
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• pp.1-6
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• 2001

This experiment was conducted to evaluated the effect of maturity at harvest on the changes in quality of round baled rye silage at forage experimental field of Grassland and Forage Crops Division, National Livestock Research Institute, RDA, Suwon in 1998. The experimental design was a split-plot design with three replications. The main plots were three different harvest stages : boot, heading and flowering stages, and the subplots were days after ensiling : 1, 2, 3, 5, 10, 30, 45, and 60 days. The wilting period of boot, heading and flowering stages were 1, 0.5 and 0.5 days, respectively. The final pH of rye silage was higher in the order of flowering, boot and heading stages. And pH of flowering stage began to change at early fermentation period, but that of boot and heading stages was delayed 1~2 days. Ammonia-N content of boot stage was highest. and that was increased as fermentation progressed. But Ammonia-N of heading stage was decreased to 30 days. then that was increased after 45 days fermentation. Among fermentation periods, inside temperature of deep place was not affected by external temperature. And that of deep place was increased to 3$0^{\circ}C$ at early fermentation. then decreased as fermentation progressed. However surface temperature was affected by external temperature after 10 days. Acetic acid content was not changed with 5 days by harvest stages, but that of boot stage was increased after 10 days. Butyric acid of boot stage was increased after 5 days. but that of heading stage was increased after 10 days. However lactic acid was increased from 1~2% to 6~8%. Lactic acid bacteria (LAB) of heading and flowering stages were highest at 5 days fermentation, and that of boot stage was highest at 10 days fermentation. The results of this study indicate that fermentation of round baled rye silage occur within 5 days. Therefore, any modification should be applied with an 5 days for high quality of round baled rye silage.