• Korean Journal of Veterinary Service
• /
• v.32 no.1
• /
• pp.33-41
• /
• 2009

In order to develop probiotic strain for pigs, Lactobacillus spp. (527 isolates), Streptococcus spp. (95 isolates) and Bifidobacterium spp. (25 isolates) were isolated from the feces of 35 pigs. These isolates were tested through in vitro experiment such as acid tolerance at pH 2.0 (Lactobacillus spp. and Streptococcus spp.) or pH 3.0 (Bifidobacterium spp.), bile tolerance in MRS broth containing 0.3% (w/v) Oxgall, heat resistance at $70^{\circ}C$ and $80^{\circ}C$ for 5 min, antibiotic resistance, antimicrobial activity against pathogenic bacteria and Caco-2 cell adherence assay. Finally ten most superior strain (5 Lactobacillus spp. strain, 3 Bifidobacterium spp. strain and 2 Streptococcus spp. strain) were selected as potential candidate for probiotic use in pig industry. It could be used as an alternative to antibiotics in feed additives.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 2005.05a
• /
• pp.331-337
• /
• 2005

한우와 홀스타인의 분변으로부터 MRS배지와 LAPT배지를 이용하여 무작위 선발법으로 54균주의 유산균을 1차로 분리 하였다. 1차로 분리된 54균주에 대해 내담즙성이 우수한 10균주를 분리 한 다음 내산성을 조사한 결과 인공위액 pH2.5에서 LS1, LS15 및 LL6 균주가 각각 66.5%, 82.6% 및 80.7%의 생존율을 나타내었다. Sal. typhimurium, Sta. aureus 및 Cl. perfringens 의 병원균에 대해 가장 큰 항균력을 보인 균주는 LL6와 LL7이었다. API CHL kit로 동정한 결과 LS1, LS2 및 LM1 균주는 모두 L. fermentum, LL6와 LL7 균주L. acidophilus, LS3 균주는 L. plantarum으로 각각동정 되고, 나머지 4균주는 Lactobacillus sp. 로 동정되어 분리된 10균주 모두 안전성 있는 유산 간균임을 확인하였다. 10종류의 항생제에 대한 내성을 조사한 결과 ampicillin, amoxicillin and erythromycin 에 대해서는 억제되었으나 colistin과 ciprofloxacin에 대해 모두 내성을 나타내었다. LB1, LL6 및 LL7 균주는 gentamicin과 neomycin에 대해 내성을 보여 주었다. 분리 동정된 균주 중에 내산성, 내담즙성 및 병원성균에 대한 항균력이 우수한 것으로 probiotic 유산균으로 사용가능성이 높은 것은 LL6인 L. acidophilus 로 나타났다.

• Microbiology and Biotechnology Letters
• /
• v.25 no.2
• /
• pp.229-234
• /
• 1997

Shizandra chinensis(SC) and Pinus regida(PR) showed antimicrobial activity against 3 strains(B-5, D-1, A-1) of lactic acid bacteria(LAB) isolated from kimchi among eight kinds of plant extracts such as Shizandra chinensis, Phellodendron amurense, ornus officinalis, Pinus regida, Allium tuberosum, Machilus thunbergii, Cyperus rotundus and Schizonepeta tenuifloia. The growth of LAB was inhibited apparently in modified MRS broth containing 1% Schizandra chinensis at $35^{\circ}C$. Pinus regida showed weaker inhibitory effect on the growth of isolated LAB than Shizandra chinensis. pH of SC added kimchi did not change greatly compare with control during 25 days of fermentation. Degree of titratable acidity change and ratio of reducing sugar utilization in control were more higher than in SC added kimchi during fermentation. Growth of total bacteria and lactic acid bacteria was inhibited about 1 to 2 $log_10$ cycle by addition of SC extracts during kimchi fermentation for 10 days at $10^{\circ}C$. Fermentation of kimchi was delaved about 5 to 7 days by addition of 1 or 2% of SC. extract, but sensory quality (falvor, taste and overall acceptability) of SC added kimchi was lower than that of control (p>0.05).

• Food Science and Preservation
• /
• v.11 no.3
• /
• pp.405-410
• /
• 2004

Leuconostoc mesenteroides subsp. cremoris DLAB19 were investigated under various culture conditions to maximize the production of antimutagenic substance(s) against aflatoxin Bl(AFBl) on Salmonella enterica serovar Typhimurium TAI00 and TA98. The MRS medium containing glucose(2$\%$) as a carbon source and yeast extract(1 $\%$) as a nitrogen source resulted in the highest production of the antimutagenic substance(s) against aflatoxin Bl(AFBl) in the culture supernatant of Leu. mesenteroides subsp. cremoris DLAB19. Optimal pH of the medium, culture temperature and shaking speed for the antimutagenic substance(s) production were pH 7.0, 30$^{\circ}C$ and 150 rpm, respectively. Under the optimal condition, the antimutagenic effects of Leu. mesenteroides subsp. cremoris DLAB19 culture supernatant were 87.11 $\%$ on S. enterica serovar Typhimurium TA100 and 75.04 S. enterica serovar Typhimurium TA98.

• Microbiology and Biotechnology Letters
• /
• v.44 no.2
• /
• pp.201-207
• /
• 2016

The aim of this study was to investigate the potential of lactic acid bacteria (LAB) strains as probiotics. Two strains were isolated from healthy chicken cecum and their acid and bile tolerance, residual organic acids, antibacterial activity against pathogenic bacteria, and immunomodulation activity were measured. Identification of the isolated strains was performed using the API 50CHL system and phylogenetic analysis using 16S rDNA sequencing. The isolates were determined to be Lactobacillus sakei strains. The acid tolerance of strains L2 and L8 was high enough that 75% of the inoculum survived in pH 2 for 2 h. The bile tolerance of both strains was observed at a 1% Oxgall concentration in MRS broth. The production of organic acids (lactic acid and acetic acid) and pH changes during growth were monitored and the maximum concentrations were obtained after 48 h of incubation. Culture supernatants of the two LAB strains showed strong antibacterial activity against pathogenic bacteria. The heat-killed LAB cells also induced high levels of immune cell proliferation compared with the control, and stimulated IL-6 and TNF-α production in mouse macrophages. Therefore, L. sakei strains L2 and L8 can be considered suitable probiotic bacteria.

• Food Science of Animal Resources
• /
• v.22 no.2
• /
• pp.164-171
• /
• 2002

The purpose of this study was to evaluate inhibitory activity of a bacteriocin mixture from lactic acid bacteria(LAB) against foodborne pathogens. Each bacteriocin solutions were prepared by growing nine strains of bacteriocin producers in MRS broth for 18~24 h followed by centrifugation(8000$\times$g, 20 min, 4$^{\circ}C$). Bacteriocins were purified from ammonium sulfate precipitation and were resuspended in 50 mM phosphate buffer(pH 7.0). Nine bacteriocins were mixed together and then allowed to freeze at -2$0^{\circ}C$. The mixture of nine bacteriocins showed enhanced inhibitory activity compared to each of bacteriocins and inhibited the Gram negative pathogens including Escherichia coli 0157:H7, Klebsiella pneumoniae, Pseudomonas chlororaphis and Shigella sonnei. The mixture of bacteriocin solutions was significantly lower than controls when a freeze-dried bacteriocin mixture was added to frank sausage, Mozzarella cheese and pork loin. With addition of bacteriocin mixture, total mesophilic bacteria in pork loin were constant over storage period, whereas total mesophilic bacteria in Mozzarella cheese and frank sausang slightly increased. Total viable cells of control group increased during storage without bacteriocin treatment. Volatile base nitrogen content of pork loin during storage also increased significantly without bacteriocin treatment. The bacteriocin mixture was capable of inhibiting pathogenic and spoilage microorganisms and extending the shelf-life of cheese and meat products during storage.

• Microbiology and Biotechnology Letters
• /
• v.49 no.2
• /
• pp.131-137
• /
• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• Journal of radiological science and technology
• /
• v.26 no.2
• /
• pp.57-61
• /
• 2003

The purpose of this study is to compare both 1.5T and 4.7T in Praietal White matter material Phantom using the same methodology at both field strengths. Data at both field strengths are compared in terms of $T_2$ relaxation times, line widths and SNRs MR imaging and $^1H$ MR spectroscopy were performed on GE 1.5T SIGNA system and Broker Biospec 4.7T/30 MRI/MRS system. After phantom axial scan $^1H$ MRS was obtained from T2 weighted image by 3-dimensional localization technique(PRESS : Point RE solved spectroscopy Sequence) this phantom is composed of an aqueous solution 36.7 mmol/L of NAA, 25.0 mmol/L of Cr, 6.3 mmol/L of choline chloride, 30.0 mmol/L or Glu, and 22.5 mmol/L of MI(adjusted to a pH of 7,15 in a phosphate buffet). Data processed using software developed inhouse. At 1.5T, T2 relaxation times for Cho, Cr, and NAA were $0.41{\pm}0.07,\;0.26{\pm}0.04,\;0.46{\pm}0.07$ while at 4.7T they were $0.17{\pm}0.03,\;0.14{\pm}0.05,\;0.20{\pm}0.03$ respectively. At 1.5T, line widths for water, Cho, Cr and NAA were $2.9{\pm}0.7,\;1.6{\pm}0.7,\;1.7{\pm}0.8,\;2.2{\pm}0.02Hz$ while at 4.7T they were $5.2{\pm}1.1,\;4.6{\pm}1.9,\;4.01{\pm}1.8,\;4.8{\pm}1.9Hz$ respectively. It can be seen that $T_2$ relaxation times were significantly shorter at 4.7 compared to 1.5T and that the line widths were also broader. The average SNRs for NAA for subjects at short and long TEs were $23.5{\pm}11.3$ at TE=20 msec ; $15.4{\pm}7.7$ at TE=272 msec at 1.5T and $40{\pm}8.3$ and $17{\pm}3.5$ respectively at 4.7T higher field strength is superior because of improved sensitivity and chemical shift dispersion. However these improvements are partially offset by increased line widths and decrease $T_2$ relaxation times, which act to reduce both sensitivity and resolution. In our experiments with the equipment available to us, 4.7T proton spectra at short TEs exhibit moderately improved sensitivity compared to 1.5T.

• Food Science of Animal Resources
• /
• v.26 no.4
• /
• pp.503-510
• /
• 2006

Survival and stability of 19 bifidobacterial strains included 13 isolates from Korean infants against acid, bile acid and oxygen exposure were examined. Acid resistance of selected strains at pH values of 4.0, 3.0 and 2.0 was tested. Among the bifidobacterial strains tested, B. bifidum B3, B. longum D6, and B. adolescentis F1 exhibited higher viable cell counts exposed to acid whereas other strains had various results. The abilities of the strains to grow in the MRS broth containing 0.2% thioglycolic acid and 0.2% oxgall were tested and the tolerance of B. bifidum B3 and B. longum D6 to bile acid were higher than that of others. Even though in same species, the tolerance of tested strains to bile acid were variable. Stabilities of tested strains to oxygen exposure were variable and B. bifidum and B. longum strains showed relatively higher viable cell counts after 48 hours exposure to aerobic incubation. These results demonstrated that the survival and stability of bifidobacterial strains to acid, bile acid, and oxygen exposure were variable and strain-dependent. Due to their tolerant ability to environmental factors like acid, bile acid, and oxygen, B. bifidum B3 and B. longum D6 had good potential properties as probiotic cultures and may be useful for industrial application.

• Food Science of Animal Resources
• /
• v.34 no.1
• /
• pp.106-114
• /
• 2014

Folic acid, one of the B group of vitamins, is an essential substance for maintaining the functions of the nervous system, and is also known to decrease the level of homocysteine in plasma. Homocysteine influences the lowering of the cognitive function in humans, and especially in elderly people. In order to determine the strains with a strong capacity to produce folic acid, 190 bacteria were isolated from various kinds of jeotgal and chungkuk-jang. In our test experiment, JA71 was found to contain $9.03{\mu}g/mL$ of folic acid after 24 h of incubation in an MRS broth. This showed that JA71 has the highest folic acid production ability compared to the other lactic acid bacteria that were isolated. JA71 was identified as Lactobacillus plantarum by the result of API carbohydrate fermentation pattern and 16s rDNA sequence. JA71 was investigated for its physiological characteristics. The optimum growth temperature of JA71 was $37^{\circ}C$, and the cultures took 12 h to reach pH 4.4. JA71 proved more sensitive to bacitracin when compared with fifteen different antibiotics, and showed most resistance to neomycin and vancomycin. Moreover, it was comparatively tolerant of bile juice and acid, and displayed resistance to Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus with restraint rates of 60.4%, 96.7%, and 76.2%, respectively. These results demonstrate that JA71 could be an excellent strain for application to functional products.