• Korean Journal of Microbiology
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• v.50 no.4
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• pp.265-274
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• 2014

Gut microbiota is a group of microorganisms that resides in the intestine and serves many important functions in human health. Using 16S ribosomal RNA sequencing analysis, a wide variety of bacteria in human gastrointestinal tract has been identified along with intriguing findings that there is a different bacterial composition among individuals. Fecal microbiota transplantation (FMT) is a procedure of stool transplantation from healthy donors to patients suffering from various diseases. Specifically, FMT is able to alter the composition of gut microbiota of recipients and therefore could be an effective treatment for the patients with gastrointestinal diseases including recurrent Clostridium difficile infection, inflammatory bowel disease, and irritable bowel syndrome. Here we review a list of human diseases related to gut microbiota disturbance and the case studies of FMT. We also summarize medicines and diagnostic tools that are under development. Therefore, gut microbiota can be a next generation's biotherapy for promotion of health and treatment of chronic diseases.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1555-1558
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• 2015

Administration of dietary fibers has various health benefits, mainly by increasing numbers of beneficial bacteria and enhancing production of short-chain fatty acids in the colon. There has been growing interest in the addition of dietary fiber to human diet, due to its prebiotic effects. This study aimed to evaluate the prebiotic activity of inulin using an in vitro batch fermentation system with human fecal microbiota. Fermentation of inulin resulted in a significantly greater ratio of Lactobacillus or Bifidobacteria to Enterobacteria strains as an index of healthy human intestine and elevated butyrate concentration, which are related to improvement of gut health.

• Journal of Microbiology and Biotechnology
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• v.24 no.6
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• pp.812-822
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• 2014

Metagenomic analysis of the human intestinal microbiota has extended our understanding of the role of these bacteria in improving human intestinal health; however, a number of reports have shown that current total fecal DNA extraction methods and 16S rRNA universal primer sets could affect the species coverage and resolution of these analyses. Here, we improved the extraction method for total DNA from human fecal samples by optimization of the lysis buffer, boiling time (10 min), and bead-beating time (0 min). In addition, we developed a new long-range 16S rRNA universal PCR primer set targeting the V6 to V9 regions with a 580 bp DNA product length. This new 16S rRNA primer set was evaluated by comparison with two previously developed 16S rRNA universal primer sets and showed high species coverage and resolution. The optimized total fecal DNA extraction method and newly designed long-range 16S rRNA universal primer set will be useful for the highly accurate metagenomic analysis of adult and infant intestinal microbiota with minimization of any bias.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.415-418
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• 2013

Since the development of the next generation sequencing (NGS) technology, 16S rRNA gene sequencing has become a major tool for microbial community analysis. Recently, human microbiome project (HMP) has been completed to identify microbes associated with human health and diseases. HMP achieved characterization of several diseases caused by bacteria, especially the ones in human gut. While human intestinal bacteria have been well characterized, little have been studied about other animal intestinal bacteria. In this study, we surveyed diversity of livestock animal fecal microbiota and discuss importance of studying fecal microbiota. Here, we report the initiation of the fecal microbiome project in South Korea.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.2
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• pp.71-79
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• 2013

The human-associated microbiota is diverse, varies between individuals and body sites, and is important in human health. Microbes in human body play an essential role in immunity, health, and disease. The human microbiome has been studies using the advances of next-generation sequencing and its metagenomic applications. This has allowed investigation of the microbial composition in the human body, and identification of the functional genes expressed by this microbial community. The gut microbes have been found to be the most diverse and constitute the densest cell number in the human microbiota; thus, it has been studied more than other sites. Early results have indicated that the imbalances in gut microbiota are related to numerous disorders, such as inflammatory bowel disease, colorectal cancer, diabetes, and atopy. Clinical therapy involving modulating of the microbiota, such as fecal transplantation, has been applied, and its effects investigated in some diseases. Human microbiome studies form part of human genome projects, and understanding gleaned from studies increase the possibility of various applications including personalized medicine.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.75-81
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• 2021

Recent gut microbiota studies have revealed the important roles of gut microbiota for our health. Increasing numbers of health functional foods have been developed every year. Development of functional food often includes ex- and in-vivo experiment to verify the beneficial effects of the functional food. To investigate effects of functional food on gut microbiota, animal models were often conducted. Beneficial effects of food can be evaluated based on how gut microbiota was shifted by food, which results in either increase in beneficial bacteria, decrease in potentially pathogenic bacteria or both. As animal experiments are generally time-consuming and laborious, we investigate how well in-vitro investigation of fecal microbiota may reflect dietary health benefits. Here, we tested 15 kinds of diets using two human subjects' fecal materials. Our results showed varying gut microbiota shifts according to diets, which suggested generally known beneficial diets (i.e. Kimchi, Chunggukjang) increased Lactobacillus and Bifidobacterium. Therefore, we suggest that in vitro fecal microbiota analysis could be used to evaluate beneficial effects of diets. Moreover, this method may be ideal to establish personalized diet.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.277-287
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• 2018

Current reports suggest that obesity is a serious global health issue. Emerging evidence has predicted strong links between obesity and the human gut microbiota. However, only a few such studies have been conducted in Asia, and the gut microbiota of lean and obese adult Asians remains largely unexplored. Here, we investigated the potential relationship between gut microbiota, body massindex (BMI), and metabolic parameters in adults from Thailand, where obesity is increasing rapidly. Fecal and blood samples were collected from 42 volunteers who were allocated into lean, overweight, and obese groups. The fecal microbiota was examined by quantitative PCR analysis. Bacteroidetes, Firmicutes, and Staphylococcus spp. and methanogens were most abundant in lean volunteers. Overweight volunteers majorly harbored Christensenella minuta and Akkermansia muciniphila, ${\gamma}-Proteobacteria$, and bacteria belonging to the genus Ruminococcus. Methanogens and bacteria belonging to the phylum Bacteroidetes were negatively correlated with adiposity markers (BMI and waist circumference), but positive correlated with high-density lipoprotein, suggesting that they can be used as leanness markers. While some of our results agree with those of previous reports, results regarding the contributions of specific taxa to obesity were inconsistent. This is the first study to report the adult gut microbiota in Southeast Asian populations using molecular techniques and biochemical markers and provides a foundation for future studies in this field.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.120-120
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• 2018

Intestinal microbiota is strongly connected to health of host. It has been reported that not only metabolic disease like diabetes and obesity, but psychological diseases are affected by composition of intestinal microbiota. To figure it out the importance of the composition and relationship between disease and microbiota, intensive researches have done with human and experimental animals. But, the composition of the intestinal microbiota could be affected by several factors such as experimental environments, feeding, water, and bedding. As a result, the data from each experimental group might be diverse. It also affects experiments about biological activities of plant materials. In this study, mouse intestinal bacteria were isolated from fresh feces and identified by 16S rRNA gene to use in biological activities of natural medicines. The fecal supernatant was anaerobically incubated at $37^{\circ}C$ for 48 hours. Colonies were picked up separately and incubated again in same condition to increase quantity to analyze and stock. The bacteria strains were listed up and could be used for many researches including biological activities of plant materials and change in composition of intestinal bacteria itself.

• Journal of Microbiology and Biotechnology
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• v.28 no.11
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• pp.1791-1799
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• 2018

Weaning stress can affect the growth performance and intestinal health of piglets. Dietary alternatives to antibiotics, such as dietary probiotics, especially those containing multiple microbial species, are a preventive strategy for effectively controlling post-weaning diarrhea. In this study, we investigated forty-eight crossbred piglets in three treatment groups for 21 days: the control and experimental groups were supplemented with Enterococcus faecium DSM 7134, Bacillus subtilis AS1.836 plus Saccharomyces cerevisiae ATCC 28338 (EBS) or Lactobacillus paracasei L9 CGMCC No. 9800 (EBL). On day 21, weaned piglets supplemented with two kinds of probiotic complexes showed increased growth performance and significantly reduced post-weaning diarrhea (p < 0.05). The EBS treatment increased acetic acid and propionic acid in the feces (p < 0.05), and the EBL treatment increased fecal acetic acid, propionic acid, butyrate and valerate (p < 0.05). Moreover, the fecal microbiota of the piglets changed markedly in EBL treatment. The addition of EBS and EBL may have similar effects on the prevention of diarrhea by improving the intestinal morphology and regulating the microbiota during the weaning period.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.856-867
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• 2017

Supplement of dietary fibers (DF) is regarded as one of the most effective way to prevent and relieve chronic diseases caused by long-term intake of a high-fat diet in the current society. The health benefits of soluble dietary fibers (SDF) have been widely researched and applied, whereas the insoluble dietary fibers (IDF), which represent a higher proportion in plant food, were mistakenly thought to have effects only in fecal bulking. In this article, we proved the anti-obesity and glucose homeostasis improvement effects of IDF from pear pomace at first, and then the mechanisms responsible for these effects were analyzed. The preliminary study by real-time PCR and ELISA showed that this kind of IDF caused more changes in the gut microbiota compared with in satiety hormone or in hepatic metabolism. Further analysis of the gut microbiota by high-throughput amplicon sequencing showed IDF from pear pomace obviously improved the structure of the gut microbiota. Specifically, it promoted the growth of Bacteroidetes and inhibited the growth of Firmicutes. These results are coincident with previous hypothesis that the ratio of Bacteroidetes/Firmicutes is negatively related with obesity. In conclusion, our results demonstrated IDF from pear pomace could prevent high-fat diet-induced obesity in rats mainly by improving the structure of the gut microbiota.