• Korean Journal of Microbiology
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• v.55 no.3
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• pp.268-273
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• 2019

The intestinal microbiomes vary according to the factors such environment, age and diet. The purpose of this study was to compare the gut microbial diversity between Korean infants receiving breast-fed milk and formula-fed milk. We analyzed microbial communities in stool samples collected from 80 Korean infants using next generation sequencing. Phylum level analysis revealed that microbial communities in both breast-fed infants group (BIG) was dominated by Actinobacteria ($74.22{\pm}3.48%$). Interestingly, the phylum Actinobacteria was dominant in formula-fed infants group A (FIG-A) at $73.46{\pm}4.12%$, but the proportions of phylum Actinobacteria were lower in formulafed infants group B and C (FIG-B and FIG-C) at $66.52{\pm}5.80%$ and $68.88{\pm}4.33%$. The most abundant genus in the BIG, FIG-A, FIG-B, and FIG-C was Bifidobacterium, comprising $73.09{\pm}2.31%$, $72.25{\pm}4.93%$, $63.81{\pm}6.05%$, and $67.42{\pm}5.36%$ of the total bacteria. Furthermore, the dominant bifidobacterial species detected in BIG and FIG-A was Bifidobacterium longum at $68.77{\pm}6.07%$ and $66.85{\pm}4.99%$ of the total bacteria. In contrast, the proportions of B. longum of FIG-B and FIG-C were $58.94{\pm}6.20%$ and $61.86{\pm}5.31%$ of the total bacteria. FIG-A showed a community similar to BIG, which may be due to the inclusion of galactooligosaccharide, galactosyllactose, synergy-oligosaccharide, bifidooligo and improvement material of gut microbiota contained in formula-milk. We conclude that 5-Bifidus factor contained in milk powder promotes the growth of Bifidobacterium genus in the intestines.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.4
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• pp.322-331
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• 2017

This study was conducted to evaluate the changes of pH, dry matter digestibility (DMD), $NH_3-N$ concentrate, gas production and volatile fatty acid (VFA) through in vitro fermentation by adding horse feces to various juice pomaces fermented with Bacillus, yeast and lactic acid bacteria. The pH range of fermented fluid with juice pomaces was 6.4-7.1, indicating that the digestion by microbial fermentation was normal. Juice pomaces adopted will be helpfully used to assist with digestion by microbes in intestines because approximately $10^9CFU/m{\ell}$ microbes were grown after 48 hours in fermented fluid. DMD rate gradually increased from 12 hours. It was 39.19% in pomaces of apple, 38.22% in grape, 37.02% in carrot, 36.2% in citrus and 34.35% in mixture respectively after 48 hours. $NH_3-N$ concentrate was not changed significantly as it was maintained at $1.5mg/100m{\ell}$ level in the entire treatment group from beginning of fermentation until 12 hours, but increased rapidly from 24 hours. Amount of gas produced was lowest in the mixture and increased rapidly after 12 hours. Total VFA increased from 24 hours and was highest at 48 hours. It was suggested that dry matter digestion was processed while fermented juice pomaces kept proper pH during in vitro digestion, and cellulose degrading microorganisms could act actively in the caecum and colon of horses.

• Journal of Life Science
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• v.19 no.6
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• pp.720-727
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• 2009

Lyophilized powder (BP2FS) of soybeans fermented with Bacillus polyfermenticus KJS-2 (B. polyfermenticus KJS-2) exhibited in vitro antibacterial activities against eight pathogenic bacteria. BP2FS was used as a fodder additive for Oplegnathus fasciatus (0. fasciatus) culture. One group (UFD) of O. fasciatus was fed a commercial fodder, while another group (FD) was fed the same fodder, but including BP2FS ($6{\times}10^{4}$ cfu $g^{-1}$ fodder), two times daily for 120 days. The mean body weight of the FD group (67.29${\pm}$12.62 g) was higher than that of the UFD group (56.56${\pm}$8.21 g) after 120 days. The survival rate of FD was 80% compared to 40% for the UFD group. Cumulative mortalities in the FD and UFD groups were 18.95% and 60.98% respectively. B. polyfermenticus KJS-2 was isolated from the intestines of the FD group and the number of viable colonies was estimated to be $1.04{\times}10^{4}$ cfu $g^{-1}$. Iridovirus and Vibrio vulnificus was detected in the organs of the UFD group but not in the FD group. All of the infected fish showed typical clinical symptoms of hemorrhage in their tail fins. Dissection of the infected internal organs revealed liver congestion and spleen enlargement - typical symptoms caused by iridovirus infection. These results clearly show that BP2FS is highly beneficial in preventing O. fasciatus from iridovirus infection.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.658-663
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• 2007

Bacillus thuringiensis is a well-known species of entomophathogenic bacteria that is widely used as a biopesticide against many insect pests. It produces parasporal crystals ($\delta$-endotoxin) and endospores during sporulation. In this report, the $\delta$-endotoxin produced by Bacillus thuringiensis BT-1 and BT-2 were characterized by Scanning Electron Microscope(SEM), Transmission Electron Microscope(TEM), SDS-PACE, and solubilization activity by alkaline solution. BT-1, BT-2 were cultured in the GBY medium, and the $\delta$-endotoxin of them was purified with discontinuous sucrose density gradient centrifugation. Their $\delta$-endotoxin was observed by SEM and TEM. Morphologically, the $\delta$-endotoxin of BT-1 was a square and flat type, whose size was $1.73{\mu}m{\times}0.7{\mu}m$, and the $\delta$-endotoxin of the BT-2 was spherical form whose size was $1.1{\mu}m{\times}0.9{\mu}m$ determined by SEM and TEM. The $\delta$-endotoxin of the BT-1 was composed of 28 kDa and 21 kDa, however, it of the BT-2 was composed of 50 kDa, 35 kDa, and 22 kDa bands determined by SDS-PACE. The purified crystals of BT-1 and BT-2 were dissolved gradually in alkaline solution as time goes by, and it was perfectly dissolved after 3 hours. It is supposed that the $\delta$-endotoxin of crystal was converted to a state of activation in the course of time in the intestines of insect.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.604-608
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• 2004

Possibility of Lactobacillus strains able to metabolize ethanol and acetaldehyde in vitro and in vitro was studied. Lactobacillus brevis strains showed higher alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activities than those of other lactic acid bacteria strains. L. brevis HY7401 exhibited the highest ADH and ALDH activities and decreased considerable amounts of ethanol and acetaldehyde in vitro. L. brevis HY7401 cell intake significantly decreased serum ethanol levels in rats fed ethanol (4g/kg BW) compared to control groups. Ethanol level in small intestines of rats fed L. brevis HY7401 was about 50%, and their acetic acid concentration was twofold higher than control. Results reveal L. brevis HY7401, isolated from human, metabolizes ethanol and acetaldehyde in vitro and in vivo.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.125-132
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• 2009

In order to develop probiotics which may be a viable alternative of antibiotic use in pig industry, five bacterial strains (Lactobacillus sp. HN 52, 92, 98, 235 and AP 116) possessing antimicrobial properties were selected from 500 strains isolates of pig intestines. The bacteriocin produced by Lactobacillus sp. HN 235 displayed a relative broad spectrum of inhibitory activity against all Enterococcus strains, Pseudomonas aeruginosa, Listeria monocytogenes and Clostridium perfringens using the spot-on-lawn method. The production of antimicrobial substance started in the middle of the exponential growth phase, reached maximum levels (6,400 AU/mL) in the stationary phase, and then declined. Bacteriocin activity remained unchanged after 30 min of heat treatment at $95^{\circ}C$ and stable from pH 2.0 to 10 for 1 h, or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.241-246
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• 2002

Seven lactic acid bacteria showing highly inhibitory activities against Salmonella gallinarum, Staphylococcus aureus, and Escherichia coli were isolated from Korean native chickens. The inhibitory activities were insensitive to various pretenses indicating that the inhibitory substance is not proteinaceous. The culture broths seem to contain other inhibitory substances in addition to lactic acid. The metabolic profile of organic acids produced by Lactobacillus pentosus K34 was investigated by GC-MSD and 28 different organic acids were detected in the culture broth. Compared with the prominent lactic acid, acetic acid, formic acid, the thirdly most abundant phenyllactic acid showed high inhibitory activity against S. gallinarum. After pHs of the acids were adjusted to S, the inhibitory activities of lactic acid, acetic acid, formic acid against S. gallinarum were greatly reduced while the inhibitory activity of phenyllactic acid was unchanged. The inhibitory activity of the phenyllactic acid was specifically high against S. gallinarum and S. aureus but very low against yeast and mold.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.12-19
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• 2016

The probiotic effects of kimchi lactic acid bacteria (LAB), Lactobacillus plantarum (Lab. plantarum) and Leuconostoc mesenteroides (Leu. mesenteroides), were studied. Lab. plantarum KCCM 11352P (LPpnu) and Leu. mesenteroides KCCM 11353P (LMpnu) were isolated from kimchi and were the predominant LAB. We compared their probiotic effects with Lactobacillus rhamnosus GG (LRgg), a well-known probiotic LAB. LPpnu showed better probiotic activities than LRgg. LMpnu also exhibited almost equal activities as LRgg. These two kimchi LAB strains exhibited resistance to gastric and bile acid, adhesion to intestines, and thermal stability. In particular, LPpnu showed excellent probiotic properties. In addition, LPpnu showed greater antioxidant activity by scavenging DPPH radicals or hydroxyl radicals than LMpnu or LRgg. LPpnu also inhibited growth of HT-29 human colon cancer cells by inducing apoptosis, increasing Bax and suppressing Bcl-2 expression compared to LMpnu or LRgg. Taken together, LPpnu and LMpnu could be used as probiotics, and LPpnu exhibited the most beneficial probiotic activities with anti-oxidant and anti-cancer properties.