• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.529.2-529
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• 1986

pSp-Si (1.6kbp) was originally found in pediococcus halophilus to be a cryptic multicopy-plasmid. Hoping that the plasmid can also replicate in Bacillus subtilis, protoplast transformation of strain 207-25 (recE) was performed using pSP-Sl onto which was added the marker of tmrB8 (on 4.9 kbp EcoRI fragment ) or tmrB+ (on 0.9 kbp xbaI fragment) gene. Though the tmrB8 gene can expres tunicamycin-resistance at the single copy state, and the tmrB+ gene exerts the resistance only at the multicopy state, we could not confirm the replication of pSP-Sl (tmrB8) or pSP-Sl(tmrB+) in B. subtilis. During the experiment, however, we unexpectedly found that the circularized 0.9 kbp xgaI fragment (tmrB+) itself, which had no replication origin, could transform strain 207-25 to tunicamycin-resistant by protoplast transformation. Southern hybridization analyses with tmrB+ and other probes revealed the integration of the fragment at a single copy state into a position other than the homologous tmrB gene. This recE independent integration of another tmrB+ gene into the chromosome may contribute to the tunicamycinresistance in the transformants.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1215-1218
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• 2010

The recombinant DNA pLR5cat_PSAB, in which pediocin PA-1 structural and immunity genes (pedAB) fused with the promoter and deduced signal sequence of an ${\alpha}$-amylase gene from a bifidobacterial strain were inserted in Escherichia coli-lactobacilli shuttle vector pLR5cat, was transferred to Lactobacillus reuteri KCTC 3679 and the transformant presented bacteriocin activity. The recombinant L. reuteri KCTC 3679 transformed with the shortened pLR5cat(S)_PSAB, where a nonessential region for the lactobacilli replicon was removed, also showed bacteriocin activity. The molecular mass of the secreted pediocin PA-1 from the recombinant bacteria was the same as that of native pediocin PA-1 (~4.6 kDa) from Pediococcus acidilactici K10 on a sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel. In cocultures with Listeria monocytogenes, the recombinant L. reuteri KCTC 3679 effectively reduced the viable cell count of the pathogenic bacterium by a 3 log scale compared with a control where L. monocytogenes was incubated alone.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.4
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• pp.516-522
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• 2016

We investigated the effects of the predominant lactic acid bacteria (LAB) on the fermentation characteristics and aerobic stability of total mixed ration (TMR) silage containing soybean curd residue (SC-TMR silage). The SC-TMR materials were ensiled in laboratory silos for 14 or 56 days. LAB predominant in SC-TMR silage were identified (Exp. 1). Lactobacillus fermentum (L. fermentum) and Streptococcus bovis (S. bovis) were found in the untreated materials, Leuconostoc pseudomesenteroides (L. pseudomesenteroides) in 14-day silage and Lactobacillus plantarum (L. plantarum) in all silages. Pediococcus acidilactici (P. acidilactici), Lactobacillus paracasei (L. paracasei), and Lactobacillus brevis (L. brevis) formed more than 90% of the isolates in 56- day silage. Italian ryegrass and whole crop maize were inoculated with P. acidilactici and L. brevis isolates and the fermentation and aerobic stability determined (Exp. 2). Inoculation with P. acidilactici and L. brevis alone or combined improved the fermentation products in ryegrass silage and markedly enhanced its aerobic stability. In maize silage, P. acidilactici and L. brevis inoculation caused no changes and suppressed deterioration when combined with increases in acetic acid content. The results indicate that P. acidilactici and L. brevis may produce a synergistic effect to inhibit SC-TMR silage deterioration. Further studies are needed to identify the inhibitory substances, which may be useful for developing potential antifungal agents.

• Fisheries and Aquatic Sciences
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• v.19 no.10
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• pp.42.1-42.10
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• 2016

The objectives of this study were to identify the histamine-forming bacteria and bacteriocin- producing lactic acid bacteria (LAB) isolated from Myeolchi-jeot according to sequence analysis of the 16S rRNA gene, to evaluate the inhibitory effects of the bacteriocin on the growth and histamine accumulation of histamine-forming bacteria, and to assess the physico-chemical properties of the bacteriocin. Based on 16S rRNA gene sequences, histamine-forming bacteria were identified as Bacillus licheniformis MCH01, Serratia marcescens MCH02, Staphylococcus xylosus MCH03, Aeromonas hydrophila MCH04, and Morganella morganii MCH05. The five LAB strains identified as Pediococcus acidilactici MCL11, Leuconostoc mesenteroides MCL12, Enterococcus faecium MCL13, Lactobacillus sakei MCL14, and Lactobacillus acidophilus MCL15 were found to produce an antibacterial compound with inhibitory activity against the tested histamine-producing bacteria. The inhibitory activity of these bacteriocins obtained from the five LAB remained stable after incubation at pH 4.0-8.0 and heating for 10 min at $80^{\circ}C$; however, the bacteriocin activity was destroyed after treatment with papain, pepsin, proteinase K, ${\alpha}$-chymotrypsin, or trypsin. Meanwhile, these bacteriocins produced by the tested LAB strains also exhibited histamine-degradation ability. Therefore, these antimicrobial substances may play a role in inhibiting histamine formation in the fermented fish products and preventing seafood-related food-borne disease caused by bacterially generated histamine.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.716-721
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• 2002

The ldhL gene encoding the $_L$-(+) lactate dehydrogenase was cloned from Lactobacillus reuteri ATCC 55739 chromosomal DNA and characterized. An internal 750-bp fiagment of ldhL gene was amplified by PCR using primers based on the conserved region of lactobacilli ldhL genes. A genomic library off. reuteri ATCC 55739 was constructed using pBR322, and colony hybridization experiments were performed using the 750-bp fragment as aprobe. One clone harboring a 4.0-kb PstI fragment was identified, and nucleotide sequencing confirmed it as an open reading frame of 972 bp in size in the middle. In addition to IdhL gene, an ORF homologous to Streptococcus pneumoniae TIGR4 hydrolase gene and 3' part of phosphomevalonate kinase gene (mvaK2) were also found on the 4 kb fragment. $_L$-LDH of L. reuteri ATCC 55739 showed the highest degree of homology with the $_L$-LDH of Pediococcus acidilactici (62.4%), fullowed by the $_L$-LDH of Lactobacillus pentosus (58.7%). The size of IdhL transcript determined by Northern blot was 1 kb, indicating the monocistronic nature of IdhL.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.219-224
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• 1992

The changes of yeast population were investigated in Mul-kimchi containing 3% salt, fermented at $15^{\circ}C$. The total viable count increased to the maximum at the optimum ripening period and then decreased rapidly. Among twenty-nine strains isolated at the optimum ripening period, the yeasts of genus Saccharomyces were predominant. The growth of five strains, Saccharomyces saitoanus Y17, Saccharomyces capensis Y29, Saccharomyces chevalieri Y13, Kluyveromyces fragilis Y2, Torulopsis candida Y9, was measured in mixed culture with each selected lactic strains, hctobaczllus plantarum Lp2, Pedzococcus pentosaceus PI, Leuconostoc mesenteroides Lu5. The results indicated that all the yeasts tested were inhibited significantly by lactic strains, however the sensitivity of yeast strains varied greatly.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.403-411
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• 2005

The relationship between plasmid (~9.5 kb) and pediocin PA-1 in P. acidilactici K10 was confirmed by plasmid curing. The pediocin operon of P. acidilactici K10 was amplified by PCR (polymerase chain reaction), and the nucleotide sequence was analyzed. The sequence of the pediocin operon of P. acidilactici K10 was similar to those of P. acidilactici strains producing pediocin PA-1/ AcH. For the expression of pediocin PA-1 in E. coli, a pQEPED (pQE-30 Xa::mature pedA) was constructed. His-tagged recombinant pediocin PA-1 (-6.5 kDa) was translated by cell-free in vitro transcription and translation using pQEPED as a DNA template. Theresult of slot blotting assay showed that transcription of recombinant pedA in E. coli M15 was induced by the addition of isopropyl-$\beta$-D-thiogalactopyranoside (IPTG) at the final concentration of 1 mM. Although the recombinant pediocin PA-1 inhibited the growth of E. coli, it was expressed in the host strain and purified by nickel-nitrilotriacetic acid (Ni-NTA) metal-affinity chromatography under denaturing condition. This is the first report for the production and one-step purification of biologically active recombinant pediocin PA-1 in E. coli.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.77-81
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• 2006

The dextransucrase activity of microorganisms which were identified as contributing to the fermentation of jeungpyeon made with yeast was measured. The dextran generated during fermentation was quantified and the viscosity changes were measured. The mechanism of network structure formation was clarified by observing the inside of the network structure over the fermentation periods ranging from 1 to 7 hr using scanning electron microscopy (SEM). The pH of jeungpyeon batter decreased significantly as the fermentation proceeded, whereas the viscosity increased. The identified lactic acid bacteria (LAB) were Leuconostoc mesenteroides subsp. mesenteroides, Pediococcus pentosaceus, Tetragenococcus halophilus, and Leuconostoc mesenteroides subsp. dextranicum. The yeast was identified as Saccharomyces cerevisiae A/Tor. Pretorien. The dextransucrase extracted from those microorganisms showed high activity. On the other hand, the amount of dextran generated from the batter increased significantly beyond 2 hr of fermentation, and the viscosity increment showed a similar trend. The SEM photos showed that the most homogeneous fine network structure was observed in the batter fermented for 2 hr. Therefore, we assumed that the dextran that was generated by microorganisms during fermentation interacted with the components of the batter to increase the stability of the network structure.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1781-1789
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• 2018

In this study, whey proteins were fermented with 34 lactic acid bacteria for 48 h at $37^{\circ}C$ and their ability to inhibit angiotensin 1-converting enzyme (ACE) activity were compared. All the lactic acid bacteria displayed varying proteolytic abilities in whey. Their fermentates also displayed varying abilities to inhibit ACE in vitro. Seven fermentates showed strong ACE inhibitory abilities between $84.70{\pm}0.67$ and $52.40{\pm}2.1%$ with $IC_{50}$ values between $19.78{\pm}1.73$ and $2.13{\pm}0.7mg/ml$. Pediococcus acidilactici SDL1414 showed the strongest ACE inhibitory activity of $84.7{\pm}0.67%$ ($IC_{50}=19.78{\pm}1.73{\mu}g/ml$). Mass spectrometry revealed that more than half (57.7%) of the low molecular weight peptides (< 7 kDa) in the P. acidilactici SDL1414 fermented samples were ACE inhibitory peptides. Our results show that P. acidilactici SDL1414 could be used as a starter culture in the dairy industry to develop antihypertensive functional foods for hypertension management.

• Food Science of Animal Resources
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• v.41 no.1
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• pp.145-152
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• 2021

Microbial bioconversion using lactic acid bacteria (LAB) provides several human health benefits. Although whey and whey-derived bioactive compounds can contribute to an improvement in human health, the potential anti-obesity effect of whey bioconversion by LAB has not been well studied. This study aimed to investigate whether bioconversion of whey by Pediococcus pentosaceus KI31 and Lactobacillus sakei KI36 (KI31-W and KI36-W, respectively) inhibits 3T3-L1 preadipocyte differentiation. Both KI31-W and KI36-W reduced intracellular lipid accumulation significantly, without decreasing 3T3-L1 preadipocyte proliferation. In addition, obesity-related transcription factor (peroxisome proliferator-activated receptor γ) and genes (adipocyte fatty acid-binding protein and lipoprotein lipase) were down-regulated significantly in 3T3-L1 cells in the presence of KI31-W and KI36-W. Collectively, these results suggest that bioconversion of whey by LAB exhibits anti-adipogenic activity and may be applied as a therapeutic agent for obesity.