• 한국미생물·생명공학회지
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• 제50권1호
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• pp.102-109
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• 2022

Bile acids are essential molecules produced by vertebrates that are involved in several physiological roles, including the uptake of nutrients. Bacterial isolates capable of producing bile acids de novo have been identified and characterized. Such isolates may provide access to novel biochemical pathways suitable for the design of microbial cell factories. Here, we further characterized the ability of Maribacter dokdonensis, Dokdonia donghaensis, and Myroides pelagicus to produce bile acids. Contrary to previous reports, we did not observe de novo production of bile acids by these isolates. Instead, we found that these isolates deconjugated the amino acid moiety of bile acids present in the growth medium used in previous reports. Through genomic analysis, we identified putative bile salt hydrolases, which could be responsible for the different bile acid modifications observed. Our results challenge the hypothesis of de novo microbial bile acid production, while further demonstrating the diverse capacity of bacteria to modify bile acids.

• Journal of Dairy Science and Biotechnology
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• 제22권1호
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• pp.13-25
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• 2004

담즙산은 cholesterol의 대사산물로 체내에서 cholesterol을 제거하는 주경로로서, 체내 cholesterol 대사를 조절하는 중요한 수단이다. 최근에 복합담즙산 분해활력이 높은 L. acidophilus에 의한 혈중 cholesterol 저하효과에 관한 많은 연구들이 보고되고 있으며, 이것은 복합담즙산의 분해로 생성되는 유리 담즙산의 분 배출 증가와 장내 cholesterol 흡수에 필요한 복합 micelle 형성의 방해에 의한 것으로 알려져 있다. 즉, 유리 담즙산은 장내에서 복합담즙산보다 용해성이 낮아서 흡수되지 않고 분으로 배출되기 쉬워, 간에서는 분으로 배출된 양만큼의 부족한 복합담즙산을 보충하기 위해 cholesterol을 이용하여 새로운 복합담즙산을 생성하기 때문에 결국은 체내의 혈중 cholesterol 수준을 감소시키는 것으로 생각된다. 또한 담즙으로 분비되는 복합담즙산은 소장내에서 cholesterol의 용해 흡수에 도움을 주지만 유리 담즙산은 cholesterol 용해성이 낮기 때문에, 장내 cholesterol 흡수에 영향을 미치는 것으로 생각된다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.203.1-203
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• 2005

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.276-286
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• 2020

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. This study was conducted for the isolation of potential lactic acid bacteria (LAB) with probiotic properties from goat milk and yogurt. Several tests were conducted in vitro using the standard procedures for evaluating the inhibitory spectra of LAB against pathogenic bacteria; tolerance to NaCl, bile salt, and phenol; hemolytic, milk coagulation, and bile salt hydrolase activities; gastrointestinal transit tolerance; adhesion properties; and antibiotic susceptibility. Among 40 LAB strains screened according to culture characteristics, five isolates exhibited antagonistic properties. Three were identified as Pediococcus acidilactici, and two were identified as Enterococcus faecium, exploiting 16S rRNA gene sequencing. All the isolates succeeded in the gastrointestinal transit tolerance assay and successively colonized mucosal epithelial cells. Based on the results of these in vitro assays, both P. acidilactici and E. faecium can be considered as potential probiotic candidates.

• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.402-407
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• 2016

Lactic acid bacteria have been identified to be effective in reducing cholesterol levels. Most of the mechanistic studies were focused on the bile salt deconjugation ability of bile salt hydrolase in lactic acid bacteria. However, the mechanism by which Lactobacillus decreases cholesterol levels has not been thoroughly studied in intact primate cells. 3-Hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) is the vital enzyme in cholesterol synthesis. To confirm the effect of probiotic Lactobacillus strains on HMGCR level, in the present study, human hepatoma HepG2 cells were treated with Lactobacillus strains, and then the HMGCR level was illustrated by luciferase reporter assay and RT-PCR. The results showed that the level of HMGCR was suppressed after being treated with the live Lactobacillus strains. These works might set a foundation for the following study of the antihyperlipidemic effects of L. acidophilus, and contribute to the development of functional foods or drugs that benefit patients suffering from hyperlipidemia diseases.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.726-732
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• 2020

Indonesian kefir grains are potential sources of lactic acid bacteria (LAB) that may act as probiotics with specific functional properties. In this study we explored the potential of the probiotic and cholesterol-lowering effect of LAB isolated from Indonesian kefir grains obtained from Bogor, Bandung, Jakarta, and Yogyakarta. The results revealed that 10 isolates showed considerable survivability at low pH and bile salt with total cell reduction of ~3 log colony-forming units per milliliter after exposure to pH 2.5 and 0.5% (w/v) bile salt for 1 and 3 h, respectively. All strains exhibited strong antimicrobial activities against pathogenic bacteria and were sensitive to a wide spectrum of antibiotics but exhibited weak bile salt hydrolase activity. Identification based on 16S RNA suggested that nine isolates were Lactobacillus kefiri and one was Lactobacillus rhamnosus. The ability of the isolates to reduce cholesterol from the media varied, ranging from 22.08% to 68.75% with the highest reduction shown by L. kefiri JK17. The ability to remove cholesterol from the media decreased greatly in resting and dead cells, ranging from 14.58% to 22.08% in resting cells and from 7.89% to 18.17% in dead cells. It can be concluded that Indonesian kefir grains contain LAB potentially acting as probiotics capable of reducing cholesterol. The cholesterol-lowering effect especially occurs when the cells are metabolically active.

• 생명과학회지
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• 제27권2호
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• pp.172-179
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• 2017

본 연구는 몽골 마유로부터 분리한 유산균 Enterococcus faecium SA5의 이화학 특성을 파악하고 유산균 E. faecium SA5의 ${\beta}$-glucosidase의 활성과 이를 통한 ginsenoside 전환을 확인하는 것을 목표로 진행되었다. E. faecium SA5는 내산성, 내담즙성을 나타내었으며 4종의 병원성 미생물(Salmonella typhimurium KCTC 3216, Listeria monocytogenes KCTC 3710, Bacillus cereus KCTC 1012, Staphylococcus aureus KCTC 1621)에 항균 활성을 가질 뿐만 아니라 항생물질 colistin, gentamycin, neomycin에 내성을 나타내었다. 또한, E. faecium SA5는 bile salt hydrolase 활성을 나타내어 혈액 내 콜레스테롤 수준 감소 효과가 있다고 사료되며 10% skim milk에서 배양하였을 때, pH가 감소하고 산도 및 생균수가 증가하는 것으로 보아 발효유 스타터로써의 활성을 갖는 것으로 판단되었다. 또한 E. faecium SA5의 ${\beta}$-glucosidase에 의해 ginsenoside $Rb_1$이 ginsenoside $Rg_3-s$와 $Rg_3-r$으로 전환되었음을 TLC 분석을 통해 확인하였다. 따라서 E. faecium SA5는 잠재적인 probiotics로 이를 이용하여 발효유 제조 및 ginsenoside 전환 관련 건강기능식품 개발에 응용할 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1731-1739
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• 2012

In this study, seven strains isolated from mustard leaf kimchi were screened for their tolerance to simulated gastric and bile juices, the adhesive properties to Caco-2 cells, and the inhibition ability of Salmonella Typhimurium ATCC 29631 adhesion. Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74, and Lactobacillus plantarum GK81, which were resistant to bile as well as gastric juices, possessed high bile-salt hydrolase (BSH) activity towards both sodium glycocholate and sodium taurocholate. The strongest in vitro adherence of $53.96{\pm}4.49%$ was exhibited by L. plantarum GK81 followed by L. acidophilus GK20 with adhesion levels of $40.72{\pm}9.46%$. The adhesion of these strains was significantly (p < 0.05) reduced after exposure to pepsin and heating for 30 min at $80^{\circ}C$. Addition of $Ca^{2+}$ led to a significant (p < 0.05) increase of the adhesion of L. acidophilus GK20, but the adhesion ability of L. plantarum GK81 was not different from the control by the addition of calcium. In the competition and exclusion experiment, the adhesion inhibition of S. Typhimurium by L. plantarum GK81 strain was much higher than the other strains. Moreover, the exclusion inhibition of S. Typhimurium by L. acidophilus GK20 was considerably high, although the inhibition activity of this strain was lower than L. plantarum GK81.

• Asian-Australasian Journal of Animal Sciences
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• 제16권5호
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• pp.726-731
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• 2003

The aim of this research was to identify candidate probiotic lactic bacteria among indigenous dadih lactic isolates. Dadih is an Indonesian traditional fermented milk of West Sumatra which is fermented naturally. Viability of the strain is critical in determining the capacity of lactic bacteria to induce immune stimulation as well as to colonize in the intestinal tract. Therefore, LAB are proposed to exert health promoting or probiotic effects in human, such as inhibition of pathogenic microflora, antimutagenic, and the reduction of cholesterol levels. This manuscript reports in vitro probiotic properties of indigenous dadih lactic bacteria, especially some important colonization factors in GI tract, such as lysozyme, acid and bile tolerance. Bile Salt Hydrolase (BSH) activity, spectrum of bacteriocin, and antimutagenic activity of bacterial cells were also assessed. Twenty dadih lactic isolates were screened further for their tolerance to low pH, at pH 2 and 3 as well as their bile tolerance. There were ten isolates classified as acid and bile acid tolerant, and further screened for lysozyme tolerance, BSH activity. The spectrum of bacteriocin activity of isolates was assayed using cell-free neutralized supernatants by agar spot test against variety of pathogens. Lc. lactis subsp. lactis IS-10285, IS-7386, IS-16183, IS-11857 and IS-29862, L. brevis IS-27560, IS-26958 and IS-23427, Leu.mesen.mesenteroides IS-27526, and L. casei IS-7257 each has good survival rate at low pH values and in the presence of lysozyme, and short lag time in the presence of 0.3 % oxgall. Lc. lactis subsp. lactis IS-11857 and IS-29862 each has high BHS activity, Lc. lactis subsp. lactis IS-10285 and IS-16183 each had a positive spectrum of bacteriocin activity against E. coli 3301 and Lysteria monocytogenes ATCC 19112, while L. brevis IS-26958 has high BHS activity as well as positive spectrum of bacteriocin against E. coli 3301, Lysteria monocytogenes ATCC 19112, and S. aureus IFO 3060. All of the ten dadih lactic strains performed in vitro acid and bile tolerance, indicating a possibility to reach the intestine alive, and display probiotic activities.

• Journal of Animal Science and Technology
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• 제64권3호
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• pp.443-461
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• 2022

This study was conducted to assess the effects of the dietary supplementation of riboflavin (as a bile salt hydrolase [BSH] inhibitor) and Bacillus subtilis on growth performance and woody breast of male broilers challenged with Eimeria spp. Intestinal bacteria, including supplemented probiotics, can produce BSH enzymes that deconjugate conjugated bile salts and reduce fat digestion. A 3 × 2 × 2 (riboflavin × Bacillus subtilis × Eimeria spp. challenge) factorial arrangement of treatments in randomized complete block design was used. On d 14, birds were gavaged with 20× doses of commercial cocci vaccine (Coccivac^R -B52, Merck Animal Health, Omaha, NE). Dietary treatment of riboflavin and B. subtilis did not affect body weight (BW), body weight gain (BWG), and feed conversion (FCR) d 0 to 14 and overall d 0 to 41. Eimeria spp challenge reduced BWG, feed intake (FI), and increased FCR between d 14 to 28, but increased BWG and lowered FCR between d 28 to 35. There were no effects of the Eimeria spp. challenge on the overall d 0 to 41 FCR and FI, but BWG was reduced. Eimeria spp. challenge increased the abdominal fat pad weight and slight woody breast incidences on processed birds on d 42. Dietary inclusion of B. subtilis and riboflavin at tested levels did not help birds to mitigate the negative impact of Eimeria spp. challenge to enhance the growth performance.