• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.131-136
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• 2006

During lactic acid bacteria (LAB) transit through the gastrointestinal tract, ingested microorganisms were exposed to successive stress factors, including low pH in the human stomach and in bile acid. These stress factors can be used as criteria for the selection of a viable probiotic strain. Four such strains (Lactobacillus helveticus SGU 0011, Lactobacillus pentosus SGU 0010, Streptococcus thermophilus SGU 0021 and Lactobacillus casei SGU 0020) were isolated from raw milk. When the identified LAB were exposed to synthetic gastric juice, whereas L. casei SGU 0020 and S. thermophilus SGU 0021 exhibited a 0% survival rate, L. helveticus SGU 0011 and L. pentosus SGU 0010 exhibited 60% and 95% survival rates. L. casei SGU 0020 and S. thermophilus SGU 0021 could not be examined with regard to their tolerances to artificial bile juice, as they uniformly died upon exposure. However, L. helveticus SGU 0011 and L. pentosus SGU 0010 individually survived at rates of 39% and 93%. Also, all four of these strains were confirmed to be tolerant of ten different antibiotics.

• 한국유가공학회:학술대회논문집
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• 2004.06a
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• pp.21-39
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• 2004

Fermented milks have been recognized as healthy foods since ancient times, but those using intestinal bacteria such as Bifidobacterium and lactic acid bacteria (LAB) are even more valuable from the standpoint of view of maintaining health. They have also now come to be recognized as important in the field of preventive medicine. Although advances in the medical sciences in the last 50 years have significantly increased the human lift span, an unfortunate fact is that many of us are now living long enough to experience chronic disorders such as coronary heart disease, hypertension, osteoporosis, diabetes and cancer. In recent years there has been renewed interest in health promotion and disease prevention by incorporating probiotic bacteria into foods to counteract harmful bacteria in the intestinal tract. Therefore, there are now a wide variety of commercial products containing prospective probiotics that claim health-promoting effects, such reductions in large botvel carcinogens and mutagens, antitumor properties, cholesterol-lowering effects, increased lactose digestion, relief from con-stipation, stimulation of immunocomponent cells and enhancement of phagocytosis. Two well-known representative probiotic is LAB and Bifidobaclerium. Traditional probiotic dairy strains of LAB which have been designated as GRAS (Generally Recognized As Safe) bacteria have a long history of safe use and most strains are considered comestible microorganisms with no pathogenic potential. Accordingly, there is considerable interest in extending the range of foods containing probiotic organisms from dairy foods to infant formulas, baby foods, and pharmaceuticals. In addition, the ingestion of probiotics, prebiotics, and symbiotic as wll as combinations of pro- and prebiotics has recently aroused renewed interest as enhancing the beneficial relationship between the host and intestinal microflora in both healthy and diseased indivisuals. Non-communicable chronic diseases such as cancer, cerebral hemorrhage, is chemic heart disease, and diabetes mellitus has recently been recognized as adult diseases in Japan as well as other countries. and are considered to be inevitably associated with aging. These diseases occur as a result of individual life styles. The Japanes Government. Ministry of Health, Labor and Welfare has proposed substituting the term 'adult diseases' with 'lifestyle-related diseases'. It has emphasized the importance of prevention rather than treatment. since the well-known increase in the elderly population in Japan is predicted to result in a variety of socioeconomic problems. n this lecture on the Present status of fermented milk products in Japan, I will report a strategy for the development of fermented milk products in Japan from the standpoint of view of research in Japan on LAB and Bifidobacteria. They could play an important role in preserving human health by controlling intestinal microflora capable of producing toxic effects on the host.

• Journal of Life Science
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• v.33 no.3
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• pp.260-267
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• 2023

Helicobacter pylori infects the mucosa, induces chronic inflammation and ulcers, and is known as a biological carcinogen. Antibiotics are used as therapeutic agents for H. pylori, but there are problems such as resistance. Thus, research is being conducted on the use of lactic acid bacteria (LAB) as an alternative therapeutic agent. There have been many studies on LAB related to kimchi. However, studies related to Gajami Sikhae, a traditional fermented seafood in Korea, are insufficient. In this study, we investigated the inhibitory effect of LAB isolated from Gajami Sikhae on H. pylori and its use as a probiotic. Forty species of LAB isolated from Gajami Sikhae were identified as Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides, and Weisella paramesenteroides, and 10 strains of 40 species were selected through liquid inhibition assay of H. pylori. The selected LAB supernatant at 1%, 5%, and 10% had a growth inhibitory effect on H. pylori 52, 51, e-53, and 309. The adjusted pH of 7.0 was used for the LAB culture supernatant, in reference to a study that the growth of H. pylori is affected by acid. All 10 strains of LAB at 5% and 10% concentration suppressed the growth of H. pylori 52, and 7 strains of LAB at 10% concentration suppressed the growth of H. pylori e-53. LAB also had the effect of suppressing the activity of urease. Finally, LAB isolated from Gajami Sikhae is expected to be useful for eradicating and preventing H. pylori.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.6
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• pp.621-628
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• 2016

Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei ) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8). The treatment was given via oral gavage for 8 weeks. The results showed that the weekly systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and aortic reactivity function were remarkably improved after 8 weeks of bacterial administration in SHR+LAB. These effects were mostly attributed by restoration of wall tension and tensile stress following the bacterial treatment. Although not statistically significant, the level of malondialdehye (MDA) in SHR+LAB serum was found declining. Increased levels of glutathione (GSH) and nitric oxide (NO) in SHR+LAB serum suggested that the bacterium exerted vascular protection through antioxidative functions and relatively high NO level that induced vasodilation. Collectively, Lb. casei strain C1 is a promising alternative for hypertension improvement.

• Journal of Environmental Science International
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• v.25 no.6
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• pp.789-798
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• 2016

Lactic acid bacteria (LAB) are industrially important microorganisms for probiotics. The recent widespread application of LAB for preparation of functional food is attributable to the accumulating scientific evidence showing their beneficial effects on human health. In this study, we isolated and characterized plant-derived LAB that show angiotensin-converting enzyme (ACE) inhibitory and antioxidant activities. The selected strain K2 was isolated from Kimchi, and identified as Lactobacillus plantarum by 16S rRNA gene analysis. The strain grew under static and shaking culture systems. They were also able to grow in different culture conditions like $25^{\circ}C{\sim}37^{\circ}C$ temperature, 4~10 pH range and ~6% NaCl concentration. L. plantarum K2 was highly resistant to acid stress; survival rate of the strain at pH 2.5 and 3 were 80% and 91.6%, respectively. The strain K2 also showed high bile resistance to 0.3% bile bovine and 0.3% bile extract with more than 74% of survival rate. The cell grown on MRS agar plate containing bile extract formed opaque precipitate zones around the colonies, indicating they have bile salt hydrolase activity. The strain showed an inhibitory activity against pathogenic bacteria such as Escherichia coli, Staphylococcus aureus and Listeria monocytogenes; antibacterial activity was probably due to the lactic acid. The K2 strain showed relatively higher autoaggregation values, antihypertensive and antioxidant activities. These results suggest that L. plantarum K2 could be not only applied as a pharmabiotic for human health but also is also starter culture applicable to fermentative products.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.83-91
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• 2015

Yogurt is a product of the acidic fermentation of milk, which affects the survival of lactic acid bacteria (LAB). The aim of this present study was to examine the survival and acid stress response of Lactobacillus rhamnosus GG to low pH environment. The survival of LAB in commercial yogurt was measured during long-term storage. The enumeration of viable cells of LAB was determined at 15-day intervals over 52-weeks at $5^{\circ}C$. L. acidophilus, L. casei, and Bifidobacterium spp. showed low viability. However, L. rhamnosus GG exhibited excellent survival throughout the refrigerated storage period. At the end of 52-weeks, L. rhamnosus GG survived 7.0 log10 CFU/mL. $F_0F_1$ ATPase activity in L. rhamnosus GG at pH 4.5 was also evaluated. The ATPase activities of the membranes were higher when exposed at pH 4.5 for 24 h. The survival of L. rhamnosus GG was attributable to the induction in $F_0F_1$ ATPase activity. In addition, the mRNA expression levels of acid stress-inducible genes at low pH were investigated by qRT-PCR. clpC and clpE genes were up-regulated after 1 h, and atpA and dnaK genes were up-regulated after 24 h of incubation at pH 4.5. These genes could enhance the survival of L. rhamnosus GG in the acidic condition. Thus, the modulation of the enzymes or genes to assist the viability of LAB in the low pH environment is thought to be important.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1790-1797
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• 2002

Lactic acid bacteria were isolated from piglets and chicken and characterized. Lactic acid bacteria showing resistance to low pH and bile, adhesion to intestinal epithelium cells, and the inhibition of Escherichia coli and Salmonella spp. were identified as Lactobacillus acidophilus. L. acidophilus PF01 survived for 2 h in MRS broth adjusted to pH 2. L. acidophilus CF07 was less resistant than L. acidophilus PF01 to pH 2, but survived at pH 2.5 for 2 h. Both of isolates were able to grow in MRS broth containing 0.3% (w/v) bile, with L. acidophilus CF07 being more tolerant to bile than L. acidophilus PF01. L. acidophilus PF01 and CF07 adhered specifically to the duodenal and jejunal epithelium cells of piglet, and the cecal and duodenal epithelium cells of chicken, respectively. Both of isolates did not adhere to the epithelium cells of the various animal intestines from which they were isolated. When L. acidophilus was cultured with E. coli and Salmonella spp. in MRS broth, MRS broth containing 2% skim milk powder or modified tryptic soy broth at $37^{\circ}C$, L. acidophilus PF01 and CF07 inhibited the growths of E. coli K88 and K99, and S. enteritidis and S. typhimurium, respectively. Both of isolates were found to possess the essential characteristics of probiotic lactic acid bacteria for piglet and chicken.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.783-791
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• 2022

Gamma-aminobutyric acid (GABA) improves various physiological illnesses, including diabetes, hypertension, depression, memory lapse, and insomnia in humans. Therefore, interest in the commercial production of GABA is steadily increasing. Lactic acid bacteria (LAB) have widely been reported as a GABA producer and are safe for human consumption. In this study, GABA-producing LAB were preliminarily identified and quantified via GABase assay. The acid and bile tolerance of the L. plantarum FBT215 strain were evaluated. The one-factor-at-a-time (OFAT) strategy was applied to determine the optimal conditions for GABA production using HPLC. Response surface methodology (RSM) with Box-Behnken design was used to predict the optimum GABA production. The strain FBT215 was shown to be acid and bile tolerant. The optimization of GABA production via the OFAT strategy resulted in an average GABA concentration of 1688.65 ± 14.29 ㎍/ml, while it was 1812.16 ± 23.16 ㎍/ml when RSM was applied. In conclusion, this study provides the optimum culture conditions for GABA production by the strain FBT215 and indicates that L. plantarum FBT215 is potentially promising for commercial functional probiotics with health claims.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1495-1500
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• 2008

In an attempt to develop a probiotic formulation for poultry feed, a number of lactic acid bacteria (LAB) were isolated from chicken intestinal specimens and a series of in vitro experiments were performed to evaluate their efficacy as a potential probiotic candidate. A total of 650 LAB strains were isolated and screened for their antagonistic potential against each other. Among all the isolates only three isolates (TMU121, 094 and 457) demonstrated a wide spectrum of inhibition and were thus selected for detailed investigations. All three selected isolates were able to inhibit the growth of E. coli and Salmonella species, although to variable extent. The nature of the inhibitory substance produced by the isolates TMU121 and 094 appeared to be associated with bacteriocin, as their activity was completely lost after treatment with proteolytic enzymes, while pH neutralization and catalase enzyme had no effect on the residual activity. In contrast, isolate TMU457 was able to resist the effect of proteolytic enzymes while pH neutralization completely destroyed its activity. Attempts were made to study the acid, bile tolerance and cell surface hydrophobicity of these isolates. TMU121 showed high bile salt tolerance (0.3%) and high cell surface hydrophobicity compared to the other two strains studied, while TMU094 appeared the most pH resistant strain. Based on these results, the three selected LAB isolates were considered as potential ingredients for a chicken probiotic feed formulation and were identified to species level based on their carbohydrate fermentation pattern by using API 50CH test kits. The three strains were identified as Lactobacillus fermentum TMU121, Lactobacillus rhamnosus TMU094, and Pediococcus pentosaceous TMU457.