• Food Science of Animal Resources
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• v.28 no.5
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• pp.580-586
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• 2008

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds. These conjugated dienes were found to be responsible for many biological properties related to health. The objective of this study was to evaluate the production of cis-9, trans-11 CLA by Lactobacillus acidophilus isolated from breast-fed infants. Nine different cultures were tested for their ability to produce cis-9, trans-11 CLA from free linoleic acid in MRS broth and 8% reconstituted skim milk medium supplemented with linoleic acid at $37^{\circ}C$ for 48 hr. cis-9, trans-11 CLA was not detected or detected in very small amount when cell pellets of strains grown in MRS broth and 8% reconstituted skim milk supplemented with linoleic acid of $200{\mu}g/mL$. However, free cis-9, trans-11 CLA was produced in both media. It appeared that 8% reconstituted skim milk produced more cis-9, trans-11 CLA than MRS broth. L. acidophilus NB 203 and NB 209 produced more cis-9, trans-11 CLA than other tested cultures. The inhibitory effects of supplemented linoleic acid on the growth of L. acidophilus NB 203 and NB 209 were not detected up to $3,000{\mu}g/mL$ linoleic acid addition during the growth at $37^{\circ}C$ for 48 h. The production of cis-9, trans-11 CLA by these two L. acidophilus strains increased in the logarithmic growth phase until 24 hr incubation. Under this experimental condition, the best yield of CLA isomers for L. acidophilus NB 203 and NB 209 could be obtained from medium supplemented with $500{\mu}g/mL$ linoleic acid at $37^{\circ}C$ after 24 hr of incubation. These results indicate that the use of lactic acid bacteria producing free CLA in fermented dairy products may have potential health or nutritional benefits.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.522-530
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• 2007

This experiment was carried out to measure the content of lactoferrin, IgA, $IgG_1,\;IgG_2$, in Holstein colostrum, and to test the effect of it's colostrum on the antibacterial activity to pathogenic bacteria and the growth stimulation of lactic acid bacteria. Colostrum was collected at the first, second, and third day after parturition in summer and winter season. The levels of lactoferrin, IgA, $IgG_1,\;and\;IgG_2$ in Holstein cow colostrum were 0.30 mg/mL, 0.37 mg/mL, 4.00 mg/mL, 0.37 mg/mL, respectively, on the first day of the summer season whereas they were 1.16 mg/mL, 2.60 mg/mL, 13.35 mg/mL, 1.30 mg/mL on the first day of the winter season, postpartum. Heat treated ($65^{\circ}C$ for 30 min) or non-treated colostrum showed antibacterial activity toward Escherichia coli. The growth of commercial mixed strains (Bifidobacterium longum, Lactobacillus acidophilus, Streptococcus themophilus), L. acidophilus, L. casei, L. bulgaricus, and L. lactis subsp. cremoris were improved in first, second and third day colostrum compared to normal milk. Commercial miked strains (B. longum, L. acidophilus S. themophilus) lowered the pH to 4.97-5.22 and 4.89 while increasing the titratable acidity to 0.75-0.88% and 0.70% in colostrum and normal milk, respectively. However, L. casei, L. bulgaricus, L. lactis subsp. cremoris lowered the pH to 5.96-6.47 and 6.5-6.8 while increasing the titratable acidity to 0.29-0.48% and 0.20-0.25% in colostrum and normal milk, respectively.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.375-382
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• 2010

In present study, five strains of Lactobacillus acidophilus GK20, Lactobacillus brevis GK55, Lactobacillus paracasei GK74, Lactobacillus plantarum GK81, and Leuconostoc mesenteroides GK104 isolated from the mustard leaf kimchi were investigated for resistance to reactive oxygen species (ROS) and antioxidant activity. L. acidophilus GK20, L. brevis GK55, L. paracasei GK74, and L. plantarum GK81 were resistant to hydrogen peroxide (0.5 mM), showing a survival rate of 50% or more. In particular, L. acidophilus GK20 and L. paracasei GK74 were the most superoxide anions-resistant and L. paracasei GK74 and L. plantarum GK81 were most likely survive hydroxyl radicals. Meanwhile, the intracellular cell-free extract (ICFE) from L. plantarum GK81 exhibited significantly higher DPPH radical scavenging values ($96.4{\pm}2.8%$) than the intact cells (IC). The ICFE of L. plantarum GK81 showed the highest superoxide radical scavenging ability and chelating activity for $Fe^{2+}$ ions among the 5 lactic acid bacteria (LAB) tested, and IC and ICFE from L. plantarum GK81 demonstrated excellent reducing activity, which was higher than those of BHA and vitamin C as a positive control.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.73-83
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• 2014

The objective of the this study was to investigate the binding capacity and removal ability of lactic acid bacterial strains obtained from Korean soybean paste for mutagenic heterocyclic amines (HCAs) formed during cooking of protein-rich food at high temperature. Among 19 strains identified by carbohydrate fermentation and 16S rRNA sequencing, the live cell or cell-free culture supernatant of Lactobacillus acidophilus D11, Enterococcus faecium D12, Pediococcus acidilactici D19, L. acidophilus D38, Lactobacillus sakei D44, Enterococcus faecalis D66, and Lactobacillus plantarum D70 inhibited the mutagenesis caused by either 3-amino-1,4-dimethyl-5H-pyrido[4,3-b] indole (Trp-P-1) or 3-amino-1-methyl-5H-pyrido[4,3-b] indole (Trp-P-2) in Salmonella typhimurium TA98 and TA100. The bacterial cells of the isolated strains showed greater binding activity than the pure cell wall, exopolysaccharide, and pepetidoglycan. The carbohydrate moieties of the cell wall or protein molecules on the cell surface have a significant role in binding Trp-P-1 and Trp-P-2, since protease, heating, sodium metaperiodate, or acidic pH treatments significantly (P<0.05) reduced the binding efficacy of the tested bacteria. Addition of metal ions or sodium dodecyl sulfate decreased the binding ability of E. faecium D12, L. acidophilus D38, and E. faecalis D66. Therefore, the binding mechanisms of these strains may consist of ion-exchange and hydrophobic bonds. Especially, the high mutagen binding by L. acidophilus D38 and L. plantarum D70 may reduce the accumulation or absorption of Trp-P-1 and Trp-P-2 in the small intestine via increased excretion of a mutagen-bacteria complex.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.156-168
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• 2015

The objective of this study is to investigate the anti-Helicobacter pylori and anti-cancer activities of the live cells (LC), cell-free culture supernatants (CFCS), and bacteriocin solution (BS) obtained from Lactobacillus acidophilus BK13 and Lactobacillus paracasei BK57 strains. After incubation for 30 h in MRS broth, the concentration of lactic acid produced by L. paracasei BK57 ($155.9{\pm}10.2mM$) was higher than in MRS broth using L. acidophilus BK13 ($126.8{\pm}7.9mM$). Maximum bacteriocin activity (128 AU/ml) of BK13 strain was observed after 30 h of cultivation at $37^{\circ}C$, however its magnitude was significantly lower than that of BK57 strain (256 AU/ml). The LC of L. acidophilus BK13 and L. paracasei BK57 were able to inhibit the growth of H. pylori ATCC 43504 at different incubation times, depending on the initial inoculum of the LAB. These CFCS and BS obtained from BK13 and BK57 strains dramatically inhibited the growth, adhesive ability, and enzymatic activity of H. pylori. Meanwhile, the anti-cancer effect of the lactic acid from L. acidophilus BK13 and L. paracasei BK57 strains on AGS cells had significant differences with the control group. Therefore, these antagonistic substances-producing strains are potentially useful as new potential antimicrobial agents for the management and prevention of H. pylori infections.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1731-1739
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• 2012

In this study, seven strains isolated from mustard leaf kimchi were screened for their tolerance to simulated gastric and bile juices, the adhesive properties to Caco-2 cells, and the inhibition ability of Salmonella Typhimurium ATCC 29631 adhesion. Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74, and Lactobacillus plantarum GK81, which were resistant to bile as well as gastric juices, possessed high bile-salt hydrolase (BSH) activity towards both sodium glycocholate and sodium taurocholate. The strongest in vitro adherence of $53.96{\pm}4.49%$ was exhibited by L. plantarum GK81 followed by L. acidophilus GK20 with adhesion levels of $40.72{\pm}9.46%$. The adhesion of these strains was significantly (p < 0.05) reduced after exposure to pepsin and heating for 30 min at $80^{\circ}C$. Addition of $Ca^{2+}$ led to a significant (p < 0.05) increase of the adhesion of L. acidophilus GK20, but the adhesion ability of L. plantarum GK81 was not different from the control by the addition of calcium. In the competition and exclusion experiment, the adhesion inhibition of S. Typhimurium by L. plantarum GK81 strain was much higher than the other strains. Moreover, the exclusion inhibition of S. Typhimurium by L. acidophilus GK20 was considerably high, although the inhibition activity of this strain was lower than L. plantarum GK81.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.403-414
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• 2013

This study evaluated the physicochemical and microbiological characteristics and antioxidant properties of yogurt samples fermented with lactic acid bacteria (LAB) obtained from pickled cabbage. API 50 CHL systems and 16S rRNA nucleotide sequence analyses revealed that the isolates were Lactobacillus casei PC05 and L. acidophilus PC16. Cell counts, titratable acidity, and viscosity of the yogurt samples fermented with L. acidophilus PC16 were significantly higher than those of the samples fermented with L. casei PC05 (P<0.05). The detected cell counts and physicochemical properties were significantly lower in plain yogurt than in soy yogurt (P<0.05). Yogurt samples fermented with L. acidophilus PC16 exhibited higher antioxidant activity, measured as ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and chelate ferrous ions, than those fermented with L. casei PC05. However, the ability to scavenge superoxide anions and superoxide dismutase (SOD) activity were significantly (P<0.05) higher in yogurt samples fermented with L. casei PC05 compared to those in samples fermented with L. acidophilus PC16. The antioxidant activity of soy yogurt was significantly (P<0.05) higher than that of plain yogurt. The antioxidant activity of the tested strains resulted in lipid peroxidation inhibition (in vitro), which may be related to the elimination of free radicals, chelating ability, and reducing power. There were no significant differences in the physicochemical properties and antioxidant activities of the yogurt samples during cold storage.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.309-313
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• 2012

The purpose of this study is to simultaneously detect and identify specific genus of Lactobacillus distributed in vagina of healthy women in their twenties by using multiplex primer. Vaginal fluid samples were taken from 166 women who were healthy and did not have vaginosis symptoms caused by bacterial infection. Six species of lactic acid bacteria belong to Lactobacillus genus that are known to inhabit in healthy vagina were selected to make a species-specific multiplex primer. Multiplex primer I was specified to selectively detect L. iners, L. crispatus, L. gasseri and multiplex primer II was specified to selectively detect L. acidophilus, L. jensenii, L. fermentum. L. crispatus (77%) was most frequently detected, and L. acidophilus (57%) and L. jensenii (57%) were relatively higher than others. Although the proportion of L. iners (59%) was a little higher than those of L. acidophilus and L. jensenii, this should be further validated in healthy women's vagina to be sure since they often appear in women having bacterial vaginosis and/or during the antibiotic therapy. Conclusively, the multiplex PCR technique using the species-specific primer could a useful tool to predict variation of vaginal health condition and process of recovery from vaginal disease.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1336-1342
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• 2005

The present research work was conducted to evaluate the beneficial effects as well as the safety aspects of lactobacilli as probiotic. Lactobacilli were isolated from poultry faecal samples, feed samples and from some known preparations procured from poultry feed manufacturers. L. acidophilus and L. sporogenes were tested for the antibacterial activity against four poultry pathogens viz. Escherichia coli, Salmonella spp., Proteus spp. and Pseudomonas aeruginosa. Cell free supernatant (CFS) of L. acidophilus exhibited significantly higher antibacterial activity against Salmonella spp. at original pH (4.50${\pm}$0.02). At the adjusted pH (6.50${\pm}$0.02) significantly higher antibacterial activity was recorded against indicator organism except for P. aeruginosa. Likewise, L. sporogenes exhibited similar antibacterial activity at original as well as adjusted pH except for E. coli. Antibacterial activity against E. coli was significantly higher at adjusted pH than at original pH of CFS. The competitive exclusion of E. coli by lactobacilli over the intestinal epithelial cells (IEC) was checked. L. acidophilus strain I, which was of poultry origin, exhibited maximum attachment over IEC as compared to other three strains of non-poultry origin viz. L. acidophilus strain II, L. sporogenes strain I and II. Overall, L. acidophilus exhibited higher competitive exclusion as compared to L. sporogenes. All the lactobacilli of poultry origin were most sensitive to penicillin G, amoxycillin, ampicillin and chloramphenicol, least sensitive to sulphamethizole, ciprofloxacin, neomycin, norfloxacin and pefloxacin and resistant to metronidazole and nalidixic acid. The isolates from probiotic preparations were most sensitive to ampicillin, amoxycillin and tetracycline, least sensitive to sulphamethizole, norfloxacin, neomycin and ceftriazone and resistant to nalidixic acid and metronidazole. Eight of the multiple drug resistant lactobacilli isolates were studied for the presence of plasmids. Plasmids could be extracted from six isolates of lactobacilli. These plasmids could be responsible for bacteriocin production or for antibiotic resistance of the strains. The lactobacilli need further studies regarding their safety for use in the probiotic preparations.

• 한국유가공학회:학술대회논문집
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• 1997.05a
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• pp.41-61
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• 1997

젖산균의 유전자 연구를 촉진하기 위해 간단하고 신속한 plasmid DNA의 분리방법과 electro-poration을 이용하여 vector plasmid의 간단하고 신속한 전이방법을 얻기 위해 젖산균의 형질전환에 영향하는 요인에 대하여 연구하였으며 연구결과는 다음과 같다. 1. O'Sullivan과 Klaenhammer의 방법을 개선하여 젖산균 plasmid DNA의 분리에 좋은 결과를 얻을 수 있는 신속하고 쉬운 방법을 고안하였으며, genomic DNA 분리에 이용되는 guanidium thio-cyanate 처리방법을 plasmid의 분리에 적용할 수 있었다. 2. L. casei, L. acidophilus. L. delbruekii var. bulgaricus. L. brevis와 L. plantarum 균주에서 plasmid를 확인하였으며, 돼지 분에서 분리된 L. lactis ssp. lactis. L. fermentum과 L. plantarum에서도 plasmid를 분리 확인하였다. 3. Lactococci의 plasmid분리는 lactobacilli와는 달리 mutanolysin의 처리없이도 잘 되었으며, L. lactis ssp. lactis와 Ent. faecalis에서 plasmid를 확인하였다. 4. E. coli plasimd 분리에 이용되는 MPS membrane filter 방법으로 젖산균 plasmid pLZ12의 분리가 가능하였으나, 세포파편이 filter를 막아 사용에 어려움이 있는 것으로 확인되었다. 5. Plasmid 분리없이 electroporation을 이용한 세포 대 세포 전이법으로 간편하고 빠르게 E. coli DH5${\alpha}$에 E. coli Jm109의 plasmid pBX19, pBR322를 전이시켰다. 6. L. lactis ssp. lactis 균주에 lysozyme 처리시 30${\sim}$80%의 생존율을 보였으며, 대부분의 L. acidophilus 균주의 경우 약 70%의 생존율을 보였다. L. casei 102S의 경우는 45분간 처리 시에도 100%의 생존율을 보였다. 8. L. lactis ssp. lactis 균주에 pLZ12를 6.0kV에서 전이시킨 결과 12.5kV에서보다 형질전환 효율이 훨씬 높았으며 lysozyme 처리에 의해 형질전환 효율이 증가되었다. 9. L. acidophilus 균주에 pLZ12를 전이시 6.0kV에서는 전이가 모두 이루어졌으나, 12.5kV에서는 L. acidophilus WIESBY와 NCFM에서 전이가 이루어지지 않았으며, lysozyme 처리 후 pLZ12를 전이시켰을 때 12kV보다 6.0kV에서 형질전환 효율이 증가되었다. 10. Gene Pulser와 Progenitor II를 사용하여 pLZ12를 L. lactis ssp. lactis 균주에 전이하였을 때 Gene Pulser에 비해 Progenitor II의 형질전환 효율이 현저히 떨어졌다. L. acidophilus HY7008과 HY7001은 두 기기 모두 형질전환이 이루어졌으나, L. acidophilus WEISBY와 NCFM은 Progeni-tor II에서 전이가 일어나지 않았으며, Gene Pulser에서 전이균주를 얻어 두 electroporator간에 형질전환 효율의 차이를 보였다. 11. L. casei 102S에 pLZ12를 electroporation시 낮은 전압에서 형질전환 효율이 비교적 좋았으며, 배양 시기를 달리하여 전이시켰을 때 대수생장 말기의 세포가 형질전환 효율이 좋았다. 12. L. casei 102S세포를 각각 10% glycerol, EB, 2차 증류수 등에 녹여 electroporation을 실시하였을 때 각각 $3.8{\times}10^3$, $5.0{\times}10^2$,1.5${\times}10^2$cfu의 형질전환 효율을 보였으며, 1.0mM HEPES, TE buffer를 사용하였을 때에는 전이가 이루어지지 않았다. 13. Plasmid pLZ12의 농도를 달리하여 electroporation을 하였을 때 형질전환 효율이 농도에 비례하여 증가하였다. 14. L. casei 102S에 대수생장 말기의 세포를 채취하여 10% glycerol, 200 Ohms, 25 ${\mu}$FD, 10kV/cm로 plasmid pLZ12를 electroporation할 때 최대 형질전환 효율인 3.8${\times}$10$^{3}$cfu를 얻었으며, lysozyme 처리가 다른 젖산균과는 달리 형질전환 효율을 증가시키지 못하였다. 15. L. casei 102S 세포를 10% glycerol과 EB에 녹여 -20$^{\circ}C$에서 냉동시킨 다음 1일과 7일 후의 세포를 electroporation한 결과 냉동시 세포에 손상을 주는 것으로 인식되었다.