• 한국축산식품학회지
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• 제32권5호
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• pp.635-643
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• 2012

As an appraisal for the application of a new starter culture, more than 200 lactic acid bacteria strains were isolated from raw milk and healthy human feces. The strains showing excellent growth and acid production ability in 10% skim milk media were selected and identified as Lactobacillus casei based on the results of their API carbohydrate fermentation patterns, as well as 16S rDNA sequence analysis. To assess the effect of L. casei strains on irritable bowel disease (IBD), the inhibitory effect of the selected strains against the nitric oxide (NO) production of lipopolysaccharide (LPS)-stimulated RAW 264.7 cells was measured. Among the tested L. casei strains, L. casei MCL was observed to have the greatest NO inhibitory activity. Additionally, L. casei MCL was found to inhibit mRNA expression of pro-inflammatory cytokines (interleukin-$1{\beta}$, IL-6, TNF-${\alpha}$), as well as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) involved in pathophysiologic processes such as inflammation. The mRNA expression of anti-inflammatory cytokines, including IL-10 and transforming growth factor-$1{\beta}$ (TGF-${\beta}$) of L. casei MCL, was confirmed using quantitative real-time PCR. In conclusion, L. casei MCL showed decreases in the expression of pro-inflammatory cytokines and up-regulated expression of the anti-inflammatory cytokine.

• 한국축산식품학회지
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• 제28권1호
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• pp.1-8
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• 2008

최근까지 박테리오신 생산균주의 분리, 분자생물학적 메커니즘, 정제, 구조 및 작용기작, 산업적인 적용 등의 논문 등이 보고되고 있다. 또한 50개국 이상에서 치즈, 통조림식품 등에서 식품보존제로서 승인되어 있다. 박테리오신의 여러 장점으로 인해 현재 추진되고 있는 축산업 분야의 HACCP의 범위인, 사육장에서부터 식품제조에 이르기까지 항생물질, 인공적인 방부제나 식품첨가물이 적게 들어가거나 첨가되지 않은 자연식품을 선호하고 있는 실정에 적합하다. 향후 축산업에서 항생제 대체방안의 하나로서 박테리오신의 사용은 확대되리라 기대된다. 경제적인 가격 경쟁력을 갖기 위해, 대량생산에 대한 연구가 이루어져야 하며, 적절한 제형으로 보다 구체적인 적용실험이 수행되어 산업화를 앞당겨야 한다.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.603-608
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• 2005

We recently isolated a novel probiotic strain, Lactobacillus fermentum PL9005 (KCCM-10250), from infant feces and showed that it had a potential immunoenhancing effect. In the present study, a safety assessment of the bacteria was performed using a BALB/c mouse model. Mice were administered with L. fermentum PL9005 daily for 28 days. There were no detectable changes in body weight, feed intake, or clinical signs, and no significant difference in hematological parameters or blood biochemistry between the L. fermentum PL9005-fed and control groups. Bacterial translocation was detected in the mesenteric lymph nodes, liver, and spleen of some mice with and without L. fermentum PL9005 feeding, however, the organisms were not related to ingestion of L. fermentum PL9005; this was confirmed by PCR using a species-specific primer. No gross lesions were detected in the liver, spleen, or intestine of L. fermentum PL9005-fed or control mice. Mucosal thickness in the ileum, cecum, and colon of L. fermentum PL9005-fed mice was not significantly different from that of corresponding organs in control mice. No inflammation or epithelial cell degeneration in the intestines was observed in any mice. These results indicate that ingestion of L. fermentum PL9005 is safe in mice and can be applied in the functional food market.

• Journal of Microbiology
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• 제45권5호
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• pp.373-378
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• 2007

Based on observations that lactic acid bacteria have the ability to activate macrophages, we assessed the potential effects of eight different Lactobacillus strains treated with gastrointestinal enzymes on the production of nitric oxide and various cytokines in macrophages. RAW 264.7 murine macrophage cells were cultured with either precipitates or supernatants of Lactobacillus strains digested with pepsin followed by pancreatin. The increased production of nitric oxide and interleukin $(IL)-1{\beta}$, IL-6, IL-12 and tumour necrosis factor $(TNF)-{\alpha}$ were observed when cultured with precipitates, and this effect was largely strain-dependent. In contrast, the exposure of RAW 264.7 cells to supernatants produced weaker or nearly undetectable effects in comparison to the effects of exposure to precipitates. The induction of nitric oxide appeared to be unaffected. These results demonstrate that nitric oxide and cytokines were effectively induced when the bacterial precipitate was treated with macrophages. The results of the present study also indicate that Lactobacillus strains treated with digestive enzymes are capable of stimulating the production of nitric oxide and cytokines in macrophages, which may modulate the gastrointestinal immune function of the host when it is given as a feed additive.

• 한국식품과학회지
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• 제29권5호
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• pp.1038-1044
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• 1997

Gram 음성 및 Gram 양성균, 효모와 곰팡이의 총9종의 균주에 대해 탄소수 8-12의 저급지방간 모노글리세라이드와 아디핀산의 항균력을 조사하였다. Gram 음성균에 대해서 저급지방산 모노글리는 단독으로 거의 항균효과를 나타내지 않았으나 AP와 혼합첨가시 적은 농도에서 강한 항균효과를 나타내었으며 동일한 농도의 AP에 대해서 MG C8이 MG C10보다 높은 항균력을 나타내었다. Gram 양성균은 저급지방산 모노글리세라이드 단독으로도 항균효과가 있었으나 높은 농도가 첨가되어야 하며 AP를 혼합첨가하면 Gram 음성균과 마찬가지로 적은 농도에서도 강한 항균작용을 나타내었으나 유산균에 대해서는 항균효과가 적었다. 또한 효모 및 곰팡이는 AP보다는 모노글리세라이드가 강한 항균작용을 나타내었다. Gram 양성균과 효모 및 곰팡이는 Gram 음성균과는 달리 모노글리세라이드중 MG C10이 MG C8보다 강한 항균작용을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제24권1호
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• pp.127-131
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• 2014

While searching for lactic acid bacteria that can restore aging-impaired immune responses, we isolated the Toll-like receptor (TLR) 2/NF-${\kappa}B$-activating strain Lactobacillus plantarum HY7712 from kimchi and investigated its immunomodulating effect in whole-body ${\gamma}$-irradiated mice. Exposure to HY7712 strongly activated NF-${\kappa}B$ signaling in RAW264.7 cells, but inhibited lipopolysaccharide-stimulated NF-${\kappa}B$ activation. Moreover, HY7712 protected against the downregulation of interferon (IFN)-${\gamma}$ and upregulation of interleukin (IL)-13 caused by ${\gamma}$-irradiation in mice. In mice, ${\gamma}$-irradiation impaired NK-cell activity against YAC-1 tumor cells, but following HY7712 exposure, the activity of NK cells was restored to 91.5% of the level measured in control mice (p < 0.05). These findings suggest that HY7712 activates the TLR2/NF-${\kappa}B$ signaling pathway and protects against the impairment of NK-cell activity caused by ${\gamma}$-irradiation or aging.

• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1216-1222
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• 2017

To develop starters for the production of functional foods or materials, lactic acid bacteria producing ${\gamma}-aminobutyric$ acid (GABA) were screened from jeotgals, Korean fermented seafoods. One isolate producing a high amount of GABA from monosodium $\text\tiny{L}$-glutamate (MSG) was identified as Enterococcus avium by 16S rRNA gene sequencing. E. avium M5 produced $18.47{\pm}1.26mg/ml$ GABA when incubated for 48 h at $37^{\circ}C$ in MRS broth with MSG (3% (w/v)). A gadB gene encoding glutamate decarboxylase (GAD) was cloned and overexpressed in E. coli BL21 (DE3) using the pET26b (+) expression vector. Recombinant GAD was purified through a Ni-NTA column and the size was estimated to be 53 kDa by SDS-PAGE. Maximum GAD activity was observed at pH 4.5 and $55^{\circ}C$and the activity was dependent on pyridoxal 5'-phosphate. The $K_m$ and $V_{max}$ values of GAD were $3.26{\pm}0.21mM$ and $0.0120{\pm}0.0001mM/min$, respectively, when MSG was used as a substrate. Enterococcus avium M5 secretes a lot of GABA when grown on MRS with MSG, and the strain is useful for the production of fermented foods containing a high amount of GABA.

• Journal of Microbiology
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• 제40권2호
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• pp.156-160
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• 2002

The whole gal/lae operon genes of Lactococcus lactis ssp. lactis 7962 were reported as follows: galA-galM-galK-galT-lacA -lacZ-galE. The galK gene encoding a galactokinase involved in one of the Leloir pathways for galactose metabolism was found to be 1,197 bp in length and encodes a protein of 43,822 Da calculated molecular mass. The deduced amino acid sequence showed over 50% homology with GaIK proteins from several other lactic acid bacteria. The galK gene was expressed in E. coli and the product was identified as a 43 kDa protein which corresponds to the estimated size from the DNA sequence. The galactokinase activity of recombinant 5. coli was about 8 times greater against that of the host strain and more than 3 times higher than the induced L. lactis 7962.

• KSBB Journal
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• 제10권5호
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• pp.553-560
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• 1995

어린돼지의 분변으로부터 Salmonella paratyphi에 강한 항균활성을 나타내는 균주를 분리하여, 이 균주를 Lactobacillus sp. KJ-5로 동정하였다. Lactoba C cillus sp. KJ-5 배양액의 항균활성은 균주의 성장에 비례하여 증가하여 정지기에서 최대를 나타냈으며, 최적 항균활성을 위한 배양온도는 $37^{\circ}C$로서 균주의 최적 성장온도와 통일하였다. Lactobacillus sp. KJ­5 배양여액의 pH를 6.2로 조정한 경우 항균활성이 약간 감소하였으나, catalase 처리에 의해셔는 항균 활성에 아무런 영향이 없었으므로 배양중에 생성된 산이나 H101 이외의 물질이 항균활성에 관여함을 알 수 있었다. 배양여 액으로 부터 methanol과 acetone 추출에 의하여 S. paratyphi어l 항균활성을 냐타내는 항균물질을 부분정제하였다. 부분정제된 항균물질은 thin-layer chromatography에서 3개의 물질로 분리 되었으며, 이중에 하나가 항균활성을 나타내었다. 또 한 부분정제된 항균물질은 270nm에셔 최대 uv 흉 광도를 나타내였으며, 단백질 가수분해 효소의 처리 에 의하여 완전히 불활성화 되었다. 따라서 Lactob$\alpha$ C cillus sp. KJ-5가 생성하는 항균물질은 저분자량의 단백질일 것으로 추정된다.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.287-296
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• 2007

A Lactobacillus paraplantarum strain producing a bacteriocin was isolated from kimchi using the spot-on-the lawn method and named L. paraplantarum C7 [15]. The bacteriocin, paraplantaricin C7, was found to inhibit certain Lactobacillus strains, including L. plantarum, L. pentosus, and L. delbrueckii subsp. lactis. It also inhibited Enterococcus faecalis, yet did not inhibit most of the other LAB (lactic acid bacteria) tested. The maximum level of paraplantaricin C7 activity was observed under the culture conditions of $25^{\circ}C$ and a constant pH of 4.5. Paraplantaricin C7 retained 90% of its activity after 10 min of treatment at $100^{\circ}C$ and remained stable within a pH range of 2-8. Based on a culture supernatant, paraplantaricin C7 was purified by DEAE-Sephacel column chromatography and $C_{18}$ reverse-phase HPLC. SDS-PAGE and activity staining were then conducted using the purified paraplantaricin C7, and its molecular mass determined to be about 3,800 Da. The 28 N-terminal amino acids from the purified paraplantaricin C7 were determined, and the structural gene encoding paraplantaricin C7, ppnC7, was cloned by PCR using degenerate primers based on the N-terminal amino acid sequence. The nucleotide sequences for ppnC7 and other neighboring orfs exhibited a limited homology to the previously reported plantaricin operon genes. Paraplantaricin C7 is a novel type II bacteriocin containing a double glycine leader sequence.