• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.18-25
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• 2015

To understand the metabolism of flavonoid rhamnoglycosides by human intestinal microbiota, we measured the metabolic activity of rutin and poncirin (distributed in many functional foods and herbal medicine) by 100 human stool specimens. The average α-L-rhamnosidase activities on the p-nitrophenyl-α-L-rhamnopyranoside, rutin, and poncirin subtrates were 0.10 ± 0.07, 0.25 ± 0.08, and 0.15 ± 0.09 pmol/min/mg, respectively. To investigate the enzymatic properties, α-L-rhamnosidase-producing bacteria were isolated from the specimens, and the α-L-rhamnosidase gene was cloned from a selected organism, Bifidobacterium dentium, and expressed in E. coli. The cloned α-L-rhamnosidase gene contained a 2,673 bp sequcence encoding 890 amino acid residues. The cloned gene was expressed using the pET 26b(+) vector in E. coli BL21, and the expressed enzyme was purified using Ni²⁺-NTA and Q-HP column chromatography. The specific activity of the purified α-L-rhamnosidase was 23.3 µmol/min/mg. Of the tested natural product constituents, the cloned α-L-rhamnosidase hydrolyzed rutin most potently, followed by poncirin, naringin, and ginsenoside Re. However, it was unable to hydrolyze quercitrin. This is the first report describing the cloning, expression, and characterization of α-L-rhamnosidase, a flavonoid rhamnoglycosidemetabolizing enzyme, from bifidobacteria. Based on these findings, the α-L-rhamnosidase of intestinal bacteria such as B. dentium seem to be more effective in hydrolyzing (1 →6) bonds than (1 →2) bonds of rhamnoglycosides, and may play an important role in the metabolism and pharmacological effect of rhamnoglycosides.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1478-1487
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• 2019

Ulcerative colitis (UC), a chronic inflammatory bowel disease, substantially impacts patients' health-related quality of life. In this study, an effective strategy for discovering high-efficiency probiotics has been developed. First, in order to survive in the conditions of the stomach and intestine, high bile salt-resistant and strong acid-resistant strains were screened out from the fecal flora of healthy adults. Next, the probiotic candidates were rescreened by examining the induction ability of IL-10 (anti-inflammatory factor) production in dextran sodium sulfate (DSS)-induced colitis mice, and Lactobacillus sakei 07 (L07) was identified and selected as probiotic P. In the end, fourteen bifidobacterium strains isolated from stools of healthy males were examined for their antimicrobial activity. Bifidobacterium bifidum B10 (73.75% inhibition rate) was selected as probiotic B. Moreover, the colonic IL-6 and $TNF-{\alpha}$ expression of the DSS-induced colitis mice treated with L. sakei 07 (L07) - B. bifidum B10 combination (PB) significantly decreased and the IL-10 expression was up-regulated by PB compared to the DSS group. Furthermore, Bacteroidetes and Actinobacteria decreased and Firmicutes increased in the DSS group mice, significantly. More interestingly, the intestinal flora biodiversity of DSS colitis mice was increased by PB. Of those, the level of B. bifidum increased significantly. The Bacteriodetes/Firmicutes (B/F) ratio increased, and the concentration of homocysteine and LPS in plasma was down-regulated by PB in the DSS-induced colitis mice. Upon administration of PB, the intestinal permeability of the the DSS-induced colitis mice was decreased by approximately 2.01-fold. This method is expected to be used in high-throughput screening of the probiotics against colitis. In addition, the L. sakei 07 - B. bifidum B10 combination holds potential in UC remission by immunomodulatory and gut microbiota modulation.

• 한국미생물·생명공학회지
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• 제50권4호
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• pp.522-532
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• 2022

Cheonggukjang is a traditional fermented food in Korea, which is known to exert beneficial effects on health. In this study, we evaluated the effects of cheonggukjang fermented by Bacillus subtilis SCGB 574 (B574) on high fat diet (HFD)-deteriorated large intestinal health. Rats were fed with HFD or HFD supplemented with 10.1% cheonggukjang (B574). Fecal microbiota was analyzed based on 16S rRNA gene sequences, and the fecal and serum metabolome were measured using GC-MS. Our results showed that SCGB574 intake significantly reduced body weight, restored tight junction components, and ameliorated inflammatory cell infiltration. SCGB574 also shifted gut microbiota by increasing the abundance of short chain fatty acid producers such as Alistipes and Flintibacter, although it decreased the abundance of Lactobacillus. Serum and fecal metabolome analyses showed significantly different metabolic profiles between the groups. The top five metabolites increased by SCGB574 were i) arginine biosynthesis, ii) alanine, aspartate, and glutamate metabolism; iii) starch and sucrose metabolism; iv) neomycin, kanamycin, and gentamicin biosynthesis; and v) galactose metabolism. These results showed that cheonggukjang fermented by SCGB574 ameliorates adverse effects of HFD through improving intestinal health.

• Journal of Microbiology and Biotechnology
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• 제30권2호
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• pp.287-295
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• 2020

The differences between luminal microbiota (LM) and mucosal microbiota (MAM) were little known, especially in duodenum. In this study, LM and MAM in colon and duodenum of mice were investigated through 16S rRNA high-throughput sequencing. The lowest bacterial diversity and evenness were observed in duodenal LM (D_LM), followed by duodenal MAM (D_MAM). Meanwhile, the bacterial diversity and evenness were obviously increased in D_MAM than these in D_LM, while no significant difference was observed between colonic MAM (C_MAM) and colonic LM (C_LM). PCoA analysis also showed that bacterial communities of LM and MAM in duodenum were completely separated, while these in colon overlapped partly. The ratio of Firmicutes to Bacteroidetes (F/B) in D_MAM was significantly higher than that in D_LM. Lactobacillus was largely enriched and was the characteristic bacteria in D_LM. The characteristic bacteria in D_MAM were Turicibacter, Parasutterella, Marvinbryantia and Bifidobacterium, while in C_LM they were Ruminiclostridium_6, Ruminiclostridium_9, Ruminococcaceae_UCG_007 and Lachnospiraceae_UCG_010, and in C_MAM they were Lachnospiraceae_NK4A136, Mucispirillum, Alistipes, Ruminiclostridium and Odoribacter. The networks showed that more interactions existed in colonic microbiota (24 nodes and 74 edges) than in duodenal microbiota (17 nodes and 29 edges). The 16S rDNA function prediction results indicated that bigger differences of function exist between LM and MAM in duodenum than these in colon. In conclusion, microbiota from intestinal luminal content and mucosa were different both in colon and in duodenum, and bacteria in colon interacted with each other much more closely than those in duodenum.

• 한방비만학회지
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• 제9권1호
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• pp.1-14
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• 2009

Complex microbial communities play an important role in the human health and co-evolved with human in the form of symbiosis. Many literatures provide new evidences that the increased prevalence of obesity cannot be attributed solely to changes in the human genome, nutritional habits, or reduction of physical activity in our daily lives. The intestinal flora was recently proposed as an environmental factor responsible for the control of body weight and energy metabolism. A number of studies suggest that the modulation of gut microbiota affects host metabolism and has an impact on energy storage and demonstrated a role for the gut microbiota in weight gain, fat increase, and insulin resistance. Variations in microbiota composition are found in obese humans and mice and the microbiota from an obese mouse confers an obese phenotype when transferred to an axenic mouse. As well, the gut microbial flora plays a role in converting nutrients into calories. Specific strategies for modifying gut microbiota may be a useful means to treat or prevent obesity. Dietary modulations of gut microbiota with a view to increasing bifidobacteria have demonstrated to reduce endotoxemia and improve metabolic diseases such as obesity. The fermentation of medicinal herbs is intended to exert a favorable influence on digestability, bioavailability and pharmacological activity of herbal extract. Therefore we also expect that the fermented herbal extracts may open up a new area to treat obesity through modulating gut microbiota.

• 생명과학회지
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• 제28권7호
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• pp.849-856
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• 2018

설사는 경제동물의 이유시기 폐사율을 일으키는 가장 높은 요인이다. 크레오소트는 전통 의약품으로 오랜 세월동안 지사제로 사용되어 왔다. 본 연구는 흰 쥐 모델에서 크레오소트 급여가 동물의 성장 효율 및 장내 미생물에 미치는 영향을 구명할 목적으로 수행되었다. 4주령의 수컷 흰쥐 24마리를 임의로 대조구, 항생제 그룹, 크레오소트 0.4% 그룹, 크레오소트 0.8% 그룹으로 배치하였다. 대조구는 기초사료, 항생제 그룹은 apramycin 0.5%, 크레오소트 그룹은 크레오소트 0.4%와 0.8% 수준으로 하여 예비시험 기간 1주일, 본시험 기간 4주일 동안 급여하였다. 일당증체량은 실험구간 차이가 없었으나, 사료 섭취량은 Creo 0.8 그룹에서 유의적으로 증가하였다(p<0.05). 장내 미생물에 대한 문(phylum) 수준 분석 결과 Creo 0.8 그룹에서 Firmicutes가 감소하고 Bacteroidetes가 증가하여 F/B비율을 감소시키는 것으로 나타났다(p<0.05). 과(family) 수준에서는 Lachnospiraceae가 크레오소트 0.8% 수준에서 증가되었으며(p<0.01), 속(genus) 수준에서는 Turicibacter가 감소되었다(p<0.01). 종(species) 수준에서는 Clostridium disporicum이 감소되었다(p<0.01). 이상의 결과는 쥐에 크레오소트 급여는 사료 섭취량을 증가시키고 장내 미생물의 변화에 영향을 미칠 수 있다는 것을 시사한다.

• IMMUNE NETWORK
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• 제21권2호
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• pp.15.1-15.10
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• 2021

Abnormal inflammatory responses are closely associated with intestinal microbial dysbiosis. Oral administration of Qmatrix-diabetes-mellitus complex (QDMC), an Aloe gel-based formula, has been reported to improve inflammation in type 2 diabetic mice; however, the role of the gut microbiota in ameliorating efficacy of QDMC remains unclear. We investigated the effect of QDMC on the gut microbiota in a type 2 diabetic aged mouse model that was administered a high-fat diet. Proinflammatory (TNF-α and IL-6) and anti-inflammatory (IL-4 and IL-10) cytokine levels in the fat were normalized via oral administration of QDMC, and relative abundances of Bacteroides, Butyricimonas, Ruminococcus, and Mucispirillum were simultaneously significantly increased. The abundance of these bacteria was correlated to the expression levels of cytokines. Our findings suggest that the immunomodulatory activity of QDMC is partly mediated by the altered gut microbiota composition.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.133-143
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• 2014

The development of the gut is controlled and modulated by different interacting mechanisms, such as genetic endowment, intrinsic biological regulatory functions, environment influences and last but no least, the diet influence. In this work, we compared the fecal microbiota of breast-fed (BF), formula-fed (FF), and mixed-fed (MF) infants from Hebei Province, China. By using high-throughput 16S rDNA sequencing analyses, we found some differences in gut microbiota in the three groups. Firmicutes and Proteobacteria were the dominant bacteria at the phylum level in the three groups, where FF infants showed a significant depletion in Bacteroidetes (p < 0.001) and Actinobacteria (p < 0.05). Enterobacteriaceae was the dominant bacteria at the family level in the three groups, but FF infants showed higher Enterobacteriaceae enrichment than BF and MF infants (p < 0.05); the abundance of the Bifidobacteriaceae was only 8.16% in the feces of BF infants, but higher than in MF and FF infants (p < 0.05). The number of genera detected (abundance >0.01%) in BF, MF, and FF infants was only 15, 16, and 13, respectively. This study could provide more accurate and scientific data for the future study of infant intestinal flora.

• The Korean Journal of Physiology and Pharmacology
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• 제28권2호
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• pp.153-164
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• 2024

This study aimed to identify metabolic biomarkers and investigate changes in intestinal microbiota in the feces of healthy participants following administration of Lactococcus lactis GEN-001. GEN-001 is a single-strain L. lactis strain isolated from the gut of a healthy human volunteer. The study was conducted as a parallel, randomized, phase 1, open design trial. Twenty healthy Korean males were divided into five groups according to the GEN-001 dosage and dietary control. Groups A, B, C, and D1 received 1, 3, 6, and 9 GEN-001 capsules (1 × 10¹¹ colony forming units), respectively, without dietary adjustment, whereas group D2 received 9 GEN-001 capsules with dietary adjustment. All groups received a single dose. Fecal samples were collected 2 days before GEN-001 administration to 7 days after for untargeted metabolomics and gut microbial metagenomic analyses; blood samples were collected simultaneously for immunogenicity analysis. Levels of phenylalanine, tyrosine, cholic acid, deoxycholic acid, and tryptophan were significantly increased at 5-6 days after GEN-001 administration when compared with predose levels. Compared with predose, the relative abundance (%) of Parabacteroides and Alistipes significantly decreased, whereas that of Lactobacillus and Lactococcus increased; Lactobacillus and tryptophan levels were negatively correlated. A single administration of GEN-001 shifted the gut microbiota in healthy volunteers to a more balanced state as evidenced by an increased abundance of beneficial bacteria, including Lactobacillus, and higher levels of the metabolites that have immunogenic properties.

• 한국미생물·생명공학회지
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• 제49권1호
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• pp.1-8
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• 2021

Human breast milk is a potential source of bacteria for the development of the intestinal microbiota of infants. Several species within the genera Lactobacillus and Bifidobacterium were demonstrated to shape the gut microbiota of infants. In this study, the bacterial diversity was investigated in the breast milk and feces of a mother-infant pair, and probiotic candidates were identified. Importantly, the novel L. gasseri EJL and B. breve JTL strains were isolated from breast milk and infant feces samples, respectively; their completed genome was resolved using de novo sequencing. In addition, the bacterial composition in the infant's feces at 1 week revealed the prevalence of Bifidobacterium and Streptococcus; a higher diversity was observed after 3 weeks. In particular, the abundance of Akkermansia was sharply increased at 7 weeks, further increasing thereafter, up to 15 weeks. Our results suggest that human breast milk and infant's feces are a source of probiotic candidates.