• Food Science of Animal Resources
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• v.25 no.3
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• pp.357-364
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• 2005

To search probiotic microorganisms, we isolated Lactobacillus sp. from kefir, The Lactobacillus sp. strain showed $99.5\%$ of identity to species Lactobacillus rhamnosus by API kit. Lactobacillus rhamnosus showed high resistances to acidic environment, which grew well even at pH 2.0 and $1.0\%$ bile salt Enzyme activity of Lactobacillus rhamnosus was higher in amylase ($0.673\;{\mu}mol/min/mg$) than that in xylanase ($0.288\;{\mu}mol/min/mg$), cellulase($0.117\;{\mu}mol/min/mg$) and phytase($0.269\;{\mu}mol/min/mg$). Especially, the Lactobacillus rhamnosus showed high heat stability which remained $1{\times}10^6\;CFU/ml$ at $60^{\circ}C$. The maximum numbers of Lactobacillus rhamnosus on growth owe was reached at 24 h fermentation and pH was decreased to 4.6. The resistances of Lactobacillus rhamnosus to acidic pH and bile salt were better than that of Lactobacillus acidophilus used as control. When Lactobacillus rhamnosus was cultured with E. coli in MRS broth, E. coli was disappeared after 18 h. These result suggest that the isolated Lactobacillus rhamnosus has a useful probiotics properties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.1-7
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• 1997

In order to utilize fish by-products from the skipjack tuna (Katsuwonus pelamis) canning manufactures Lactobacillus buigaricus KCTC 3188 and L. piantarum KCTC 1048 were used as a starter culture for the preparation of fermented fish silage with skipjark tuna viscera. The optimum temperature and pH on barterial growth and lactic acid production of L. bulgaricus and L. plantarum in MRS broth were $35^{\circ}C$ and around pH 6.0, respectively. And the optimum concentrations of the carbohydrate sources added to the broths were $7\%$ for dextrose and $10\%$ for molasses on the basis of total weights of skipjack tuna viscera. The pH of acid treated skipjack tuna viscera silage (ASS) slightly increased from 4.0 to 4.5, while that of fermented skipjack tuna viscera silages by the use of lactic acid bacterias (FSS) was significantly declined from 5.9 to about 40 after 42 days of storage at $35^{\circ}C$. Though the content of volatile basie nitrogen (VBN) in ASS was lower than those of FSS after 42 days of storage at $35^{\circ}C$, VBN content in silages slightly increased from an initial value of $62\~65{\cdot}mg/100g$ to final value of $113\~155\;mg/100g$ over 42 days. The fermented silage by L. piantarum reached a maximum concentration of amino nitrogen and showed $81\%$ of hydrolysis degree after 4 days of storage at $35^{\circ}C$.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.52-58
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• 2014

Purpose : To establish a pH measurement system for a mouse tumor study using a clinical scanner, to develop the $^1H$ and 31P radio frequency (RF) coil system and to test pH accuracy with phantoms. Materials and Methods: The $^1H$ and the $^{31}P$ surface coils were designed to acquire signals from mouse tumors. Two coils were positioned orthogonally for geometric decoupling. The pH values of various pH phantoms were calculated using the $^1H$ decoupled $^{31}P$ MR spectrum with the Henderson-Hasselbalch equation. The calculated pH value was compared to that of a pH meter. Results: The mutual coil coupling was shown in a standard $S_{12}$. Coil coupling ($S_{12}$) were -73.0 and -62.3 dB respectively. The signal-to-noise ratio (SNR) obtained from the homogeneous phantom $^1H$ image was greater than 300. The high resolution in vivo mice images were acquired using a $^{31}P$-decoupled $^1H$ coil. The pH values calculated from the $^1H$-decoupled $^{31}P$ spectrum correlated well with the values measured by pH meter ($R^2$=0.97). Conclusion: Accurate pH values can be acquired using a $^1H$-decoupled $^{31}P$ RF coil with a clinical scanner. This two-surface coil system could be applied to other nuclear MRS or MRI.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.88-88
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• 2003

Purpose： To investigate whether there are significant changes in regional brain metabolism in patients with Parkinson's disease after thalamotomy using proton magnetic resonance spectroscopy (1H MRS). Materials and methods： Fifteen patients with Parkinson's disease of mean age 56.5 years (7 males and 8 females； mean age, 56.5 years) that have treated with levodopa were included. All patients with tremor experienced amelioration of their symptoms on the side contralateral to the thalamotomy. As a single-voxel technique, 1H MR spectra were obtained from the volume of interested regions in thalamus and primary motor cortex. Spectral parameters were： 20 ms TE, 2000 ms TR, 128 averages, 2500 Hz spectral width, and 2048 data points.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.147-152
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• 2017

A bioluminescent Lactobacillus plantarum (pLuc2) strain was constructed. The luminescent signal started to increase during the early exponential phase and reached its maximum in the mid-exponential phase in a batch culture of the strain. The signal detection sensitivity of the strain was the highest in PBS (phosphate buffered saline), followed by milk and MRS broth, indicating that the sensitivity was influenced by the matrix effect. The strain was used in millet seed fermentation which has a complex matrix and native lactic acid bacteria (LAB). The luminescent signal was gradually increased until 9 h during fermentation and abolished at 24 h, indicating that the strain could be specifically tracked in the complex matrix and microflora. Therefore, the bioluminescent labeling system can be used for monitoring LAB in food and dairy sciences and industries.

• Progress in Medical Physics
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• v.11 no.1
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• pp.73-83
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• 2000

In this study, we investigate the effects of poor shimming on quantitative measurement of ratios of metabolite levels by proton magnetic resonance spectroscopy ($^1$H MRS). Coefficient of variation (COV) of metabolite ratios for point resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) spectra was evaluated from a phantom containing in vivo levels of metabolites using a conventional whole body 1.5T MR system and conventional acquisition and analysis protocol. A statistical P-value was also calculated from a linear regression for relationship of metabolite ratios. N-acetylaspartate (NAA)/ creatine (Cr) and NAA/ choline (Cho) had low COV values for the long and short TE spectra (29.1 and 27.5%; 23.8 and 12.6 %), whereas Cho/Cr and Cr/Cho had high COV values (50.0 and 68.6 %; 27.5 and 29.3 %). A linear relationship between NAA/Cr and Cho/Cr, and between NAA/Cho and Cr/Cho revealed the statistical significance in the long and short TE spectra, respectively (P < 0.0001 and P < 0.0001; P = 0.015 and P = 0.005). There was no significant relationship between Cho/NAA and Cr/NAA in the measurement (P = 0.159; P = 0.910). The present study suggested that NAA/Cr and NAA/Cho could be useful for data with poor shimming in $^1$H MR spectroscopy. In conclusion, statistical significance of metabolite ratios indicated that the Cr and Cho levels could be interpreted as a significant alteration factor in the long and short TE spectra, and then should be used with care to provide precise metabolite quantification.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1798-1807
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• 2002

This study was conducted to investigate lactobacillus salivarius subsp. salivarius having probiotic properties to be used as the health adjuncts with fermented milk products. Acid- and bile-tolerant lactobacillus salivarius subsp. salivarius was isolated with lactobacilli MRS broth from faeces of 80 healthy persons (infants, children and adults). It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at 37$^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by 0.9-1.0% at 37$^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced 23-38% of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 h at 37$^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with 15-25 mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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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.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.144-147
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• 2006

This experiment was carried out to investigate the effect of mulberry fruit extinct on the acid production and growth of lactic acid bacteria. The extract of mulberry fruit was showed a high level of yield with 60% ethanol extraction. Lactic acid bacteria was used in a starter culture of Lactobacillus casei YIT9018 and 2782, and Lactobacillus acidophilus NCFM. After 24 hr culture in MRS broth added with 1.0, 5.0 and 10% of the extract 1.0% addition of the extract was showed pH $4.04{\sim}4.19$, titratable acidity $1.25{\sim}1.42%,\;and\;1.2{\sim}7.8{\times}10^9\;cfu/mL$ of viable cell count. The additions above 1.0% extract (5.0% and 10.0% addition) showed slightly lower effect than 1.0% addition. However, the addition of the extract showed a high effect on the growth of lactic acid bacteria comparing with the control. In yoghurt preparation with the extract, 1% addition of the extract showed a high effect on the growth of lactic acid bacteria, Therefore, it was suggested to manufacture of the yoghurt with the addition of 1% mulberry fruit extract and the inoculation of culture of Lactobacillus acidophilus for on the stimulation of growth of the lactic culture.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.89-119
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• 2004

This study was conducted to isolate lactobacilli having probiotic characteristics to be used as health adjuncts with fermented milk products. Acid tolerant strains were selected in Lactobacilli MRS broth adjusted to pH 4.0 from 80 healthy persons (infants, children and adults). And bile tolerant strains were examined in Lactobacilli MRS broth in which 1.0% bile salt was added. By estimation above characteristics, the strains No. 27, which was isolated from adult feces, was selected and identified as Lactobacillus salivarius subsp. salivarius based on carbohydrate fermentation and 16S rDNA sequencing. It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at $37^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by $0.9{\sim}1.0%$ at $37^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced $23{\sim}38%$ of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 hours at $37^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with $15{\sim}25$ mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. Purified ${\alpha}$-galactosidase was obtained by DEAE-Sephadex A-50 ion exchange chromatography, Mono-Q ion exchange chromatography and HPLC column chromatography from L. salivarius subsp. salivarius 27. The specific activity of the purified enzyme was 8,994 units/mg protein, representing an 17.09 folds purification of the original cell crude extract. The molecular weight of enzyme was identified about 53,000 dalton by 12% SDS-PAGE. Optimal temperature and pH for activity of this enzyme were $40^{\circ}C$ and 7.0 respectively. The enzyme was found to be stable between 25 and $50^{\circ}C$. ${\alpha}$-galactosidase activity was lost rapidly below pH 5.0 and above pH 9.0. This enzyme was liberated galactose from melibiose, raffinose, and stachyose, and also the hydrolysis rate of substrate was compound by HPLC. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.