• Journal of Dairy Science and Biotechnology
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• v.42 no.1
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• pp.9-17
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• 2024

This study aimed to evaluate the appropriateness of MRS-C (0.05% L-cystein; pH 5) and BHI-CM (0.05% L-cystein, 0.5% mucin) agars for the selective isolation of bifidobacteria in fecal samples compared to blood-liver-NPNL (BL-NPNL) agar. Over 200 isolated colonies were characterized morphologically and biochemically. Genomic DNA was extracted from pure cultures of the isolated strains, followed by PCR amplification of the 16S rRNA gene. Bifidobacterium longum and B. animalis were selectively isolated from MRS-C agar and Lactobacillus acidophilus and Enterococcus avium were also isolated. B. longum, B. faecale, and B. animalis were isolated from feces on BHI-CM agar; however, different Bacteroides strains (including Bac. fragilis, Bac. kiribbi, Bac. ovatus, Bac. koreensis, and Bac. salyersiae) were also detected. BL-NPNL agar successfully isolated B. longum and Bacillus, while other Bifidobacterium and Bacteroides species could not grow owing to the presence of antibiotics in the medium. The use of antibiotics in a medium can enhance the selectivity; however, antibiotics may inhibit the growth of certain bacteria in a sample. Hence, adjusting pH or adding non-antibiotic nutrients to the medium is more advantageous, than relying on antibiotics.

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.303.2-303
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• 2001

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.9-14
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• 2003

When ginsenosides Rbl, Rb2, and Rc were anaerobically incubated with commercial and human intestinal lactic acid bacteria, most commercial lactic acid bacteria did not metabolize these ginsenosides to compound K. However, lactic acid bacteria, B. minimum KK-1, Bifidobacterium cholerium KK-2, and B. cuniculi K-513, isolated from human intestinal microflora transformed these ginsensosides to compound K. When the bacterial mixtures of commercial lactic acid bacteria were incubated with these ginsenosides, these compounds were not transfformed to compound K. However, when Bzfidobacterium KK-1 and KX-2 were miked, these ginsenosides were synergistically transformed to compound K. When water extract of ginseng was incubated with these mixed bifidobacteria, compound K was potently produced. Therefore, it is suggested that, if ginseng with these mixed bifidobacteria is fermented, compound K-enforced ginseng materials could be produced that show cytotoxicity against tumor cell lines.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.162-168
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• 2001

For lactic acid fermentation of chestnut broth,10 strains of bacteria were isolated from human feces and commercial yogurt,6 of which were identified to be Bifidobacterium and the rest isolated from Acidities of the chestnut broths fermented by these strains were lower than yogurt, but more than two times higher than yogurts made from seeds or vegetables including soy milk. To stimulate acidity of the fermented broths, addition of yeast extract and tryptone peptone were the most effective at the concentration of 0.2 and 0.4%, respectively, while glucose addition above 0.5% up to 8% did not increased the acid production except a few strains of Lactoba- Cillus. Among the tested fruits and vegetables, carrot juice supplementation was the most effective in acid produc- tion by most of the tested strains. Saccharification of chestnut broth by hydrolyzing process greatly increased the acid production at 25% of cooked chestnut. However, compared to the results from the 8% of unhydrolyzed chest- nut, the net increase in acid production by hydrolysis was not much stimulative.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.1-6
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• 2001

Ten strains of plasmid-harboring Bifidobacterium sp. were isolated from the feces of adults and children, and named as Bifidobacterium sp. GE1-GE8, ST, and SH5. These plasmids were categorized into three homologous groups (pKJ50-homologous, pKJ36-homologous, and non-homologous groups) according to Southern hybridization patterns using the formerly characterized bifidobacterial plasmids, pKJ50 and pKJ36, as probes. nine strains harboring the plasmids were shown to accumulate single-stranded DNA as a replication intermediate, based on the S1 nuclease treatment and Southern hybridization. These results suggest that the strains replicate by a rolling circle mechanism. Minimal inhibitory concentrations (MIC) of the isolated bifidobacteria against several antibiotics were determined. Two strains, GE2 and GE3, showed relatively high MiC values against tetracycline ($793.6{\mu}g/ml$) and erythromycin ($153.6{\mu}g/ml$), respectively. The tetracycline resistance of GE2 disappeared when the resident plasmid of GE2 was cured by ethidium bromide. These results show that pKJ36-homologous and pKJ50-homologous plasmids are prevalent among various Bifidobacterium strains and some Bifidobacterium plasmids appear to code for antibiotic resistance.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.245-252
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• 2013

Pseudomonas aeruginosa and Acinetobacter baumannii are significant opportunistic pathogens in hospitals and are resistant to most antibiotics. Multidrug-resistant P. aeruginosa (MDRPA) and A. baumannii (MDRAB) cause severe human nosocomial infections and are more difficult to treat than methicillin-resistant Staphylococcus aureus (MRSA). Bifidobacteria are among of the most beneficial probiotics and have been widely studied for their antimicrobial activities. The present study explored the antimicrobial activity of Bifidobacterium sp. isolated from healthy Koreans against MDRPA and MDRAB. The antimicrobial activity of the isolates against MDRPA and MDRAB, which are resistant to ciprofloxacin, tobramycin, gentamicin, meropenem, and ceftazidime, was determined by modified broth microdilution methods using absorbance. Among all tested bifidobacteria isolates (nine B. adolescentis, three B. longum, and two B. pseudocatenulatum), the culture supernatant of B. pseudocatenulatum SPM1309 showed a strong growth inhibitory effect against MDRPA and MDRAB. No change in the turbidity of the mixture was observed during incubation, and its inhibitory effect occurred through bacteriostastic action. Moreover, the antibacterial activity was observed in the fraction with molecular weights <10 kDa of bifidobacteria culture supernatant, and the active fraction was heat-stable because it maintained its activity when heated at $70^{\circ}C$ for 10 min. The results suggest that this Bifidobacterium strain could have potential applications for alternative therapy in MDRPA and MDRAB infections.

• Preventive Nutrition and Food Science
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• v.20 no.1
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• pp.78-81
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• 2015

1,4-Dihydroxy-2-naphthoic acid (DHNA) is a bifidogenic growth stimulator (BGS) and could be a functional food ingredient since bifidobacteria are beneficial for human health. For that reason, lactic acid bacteria producing DHNA have been screened. A lactic acid bacterium LP1 strain isolated from a natural cheese was confirmed to produce DHNA, analyzed by a HPLC method. The strain was identified as Lactobacillus casei by 16S rRNA gene sequence analysis. The cell-free supernatant of fermented whey produced by L. casei LP1 presented the BGS activity for three bifidobacterial strains such as Bifidobacterium longum subsp. infantis KCTC 3127, Bifidobacterium bifidum KCTC 3202, and Bifidobacterium breve KCTC 3220 which were human-originated. To the best of our knowledge, a L. casei strain which can produce DHNA was firstly identified in this study.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.205.1-205.1
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• 2003

Bifidobacterium spp. is nonpathogenic. Gram-positive and anaerobic bacteria, which inhabit the intestinal tract of humans and animals. Bifidobacterium spp. plays important roles in human health. However. the influence of exogenous factors on species composition of fecal bifidobacteria is still unclear. In this study, we wished to determine whether presentation of exogenous OVA (10 $\mu\textrm{g}$/$m\ell$) could be enhanced by the culture supernatant of ten Bifidobacterium spp. (omitted)

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.176-181
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• 2002

In order to isolate and identify Bifidobacterium spp. that originated in Korea, feces were sampled from healthy Korean adults and children living in three villages, the first having a history of longevity and the other two where the diet did not include fermented milk or any pharmaceutical preparations. Through the use of Gram staining and microscopic examination for cell morphology, 23 bacterial strains presumed to be the Bifidobacterium genus were isolated from the feces of 13 out of a total of 59 Korean people. To identify the Bifidobacterium strains at the genus level, these bacteria were then analyzed by TLC and the fructose-6-phosphate phosphoketolase (F6PPK) test. The result showed that 22 of the isolated strains were confirmed to be members of the genus Bifidobacterium. All of these bifidobacteria were also identified as Bifidobacterium spp. by the fermentation test. Using a RFLP analysis, an attempt was made to identify the Bifidobacterium spp. that had been isolated from both Korean adults and children. In a genomic Southern blot analysis after digestion with two restriction enzymes (EcoRI, HindIII), all of the 14 randomly selected Korean isolates showed patterns identical to those of three different B. longum species. Another restriction enzyme, CfoI (4-bp recognition enzyme), was then used to identify the strain. Interestingly, all the Korean isolates were identified as B. longum ATCC 15708, indicating that a RFLP analysis was effective for identifying Bifidobacterium spp. at both the strain and species levels.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.191-195
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• 1993

The intestinal microflora of humans is an extraordinarily complex mixture of microorganisms, the majority of which are anaerobic bacteria. Amongst them, most prevalent bacteria are Bacteroides, Eubacterium, Peptococcus, Bifidobacteria. We isolated a Bacteroides fragilis strain from a Korean adult and examined various glycosidase activities of this strain. The activities of $N-acetyl-{\beta}-glucosaminidase,\;{\alpha}-fucosidase$, ${\beta}-glucuronidase$, chitobiase and PNPCase were stronger in Bacteroides fragilis Roid 8 than in other intestinal anaerobic bacteria. $N-acetyl-{\beta}-glucosaminidase$ was strongest, followed by ${\alpha}-fucosidase$, ${\beta}-glucuronidase$ and PNPCase. The activities of ${\beta}-galactosidase$, ${\beta}-xylosidase,\;{\alpha}-arabinofuranosidase$ were not present or very low. The activities of ${\alpha}-glucosidase$, ${\beta}-glucosidase$ and ${\alpha}-galactosidase$ were present but at a lower level than in Bifidobacterium. The effect of the carbon sources on the production of $N-acetyl-{\beta}-glucosaminidase$, ${\alpha}-fucosidase$, ${\beta}-glucuronidase$ and PNPCase of Bacteroides fragilis Roid 8 was investigated. :.actose and glucose lowered the production of the varous glycosidase enzymes studied in this work. In addition, we investigated the optimum temperature and pH of each glycosidase from Bacteroides fragilis Roid-8 using crude enzyme preparations.