• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.763-774
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• 2016

Equine gastric ulcer syndrome is one of the most frequently reported diseases in thoroughbred racehorses. Although several risk factors for the development of gastric ulcers have been widely studied, investigation of microbiological factors has been limited. In this study, the presence of Helicobacter spp. and the gastric microbial communities of thoroughbred racehorses having mild to severe gastric ulcers were investigated. Although Helicobacter spp. were not detected using culture and PCR techniques from 52 gastric biopsies and 52 fecal samples, the genomic sequences of H. pylori and H. ganmani were detected using nextgeneration sequencing techniques from 2 out of 10 representative gastric samples. The gastric microbiota of horses was mainly composed of Firmicutes (50.0%), Proteobacteria (18.7%), Bacteroidetes (14.4%), and Actinobacteria (9.7%), but the proportion of each phylum varied among samples. There was no major difference in microbial composition among samples having mild to severe gastric ulcers. Using phylogenetic analysis, three distinct clusters were observed, and one cluster differed from the other two clusters in the frequency of feeding, amount of water consumption, and type of bedding. To the best of our knowledge, this is the first study to investigate the gastric microbiota of thoroughbred racehorses having gastric ulcer and to evaluate the microbial diversity in relation to the severity of gastric ulcer and management factors. This study is important for further exploration of the gastric microbiota in racehorses and is ultimately applicable to improving animal and human health.

• Journal of Digestive Cancer Research
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• 제12권1호
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• pp.6-14
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• 2024

Gastric cancer is the 4th leading cause of death worldwide. The primary cause of gastric cancer is known to be Helicobacter pylori (H. pylori). The advancement of molecular biology has enabled the identification of microbiomes that could not be confirmed through cultivation, and it has been revealed that the microbial communities vary among normal mucosa, atrophic gastritis, intestinal metaplasia, and gastric cancer. It has also been confirmed that the composition of the microbial community differs depending on the presence or absence of H. pylori. Whether changes in the microbiome are causative factors in the carcinogenesis process is not yet clear. Experiments using animal models and in vitro studies on the role of microbes other than H. pylori in the carcinogenic process are underway, but the data is still insufficient.

• The Korean journal of internal medicine
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• 제39권4호
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• pp.590-602
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• 2024

Background/Aims: Recent research has increasingly focused on the role of the gastric microbiome in the development of gastric cancer. We aimed to investigate the changes in the microbiome during gastric carcinogenesis in structural and functional aspects, with a specific focus on the association between oral and gastric microbiomes. Methods: We collected saliva, gastric juice, and gastric tissue samples from 141 patients at different stages of gastric carcinogenesis and processed them for microbiome analysis using 16S rRNA gene profiling. The alpha and beta diversities were analyzed, and the differences in microbiome composition and function profiles were analyzed among the groups, as well as the correlation between changes in the oral and gastric microbiomes during carcinogenesis. Results: We observed significant differences in microbial diversity and composition between the disease and control groups, primarily in the gastric juice. Specific bacterial strains, including Schaalia odontolytica, Streptococcus cristatus, and Peptostreptococcus stomatis, showed a significant increase in abundance in the gastric juice in the low-grade dysplasia and gastric cancer groups. Notably, the correlation between the oral and gastric microbiota compositions, increased as the disease progressed. Predictive analysis of the metagenomic functional profiles revealed changes in functional pathways that may be associated with carcinogenesis (ABC transport and two-component systems). Conclusions: During gastric carcinogenesis, the abundance of oral commensals associated with cancer increased in the stomach. The similarity in microbial composition between the stomach and oral cavity also increased, implying a potential role of oral-gastric bacterial interactions in gastric cancer development.

• Journal of Ginseng Research
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• 제42권3호
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• pp.255-263
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• 2018

Orally administered ginsengs come in contact with the gut microbiota, and their hydrophilic constituents, such as ginsenosides, are metabolized to hydrophobic compounds by gastric juice and gut microbiota: protopanxadiol-type ginsenosides are mainly transformed into compound K and ginsenoside Rh2; protopanaxatriol-type ginsenosides to ginsenoside Rh1 and protopanaxatriol, and ocotillol-type ginsenosides to ocotillol. Although this metabolizing activity varies between individuals, the metabolism of ginsenosides to compound K by gut microbiota in individuals treated with ginseng is proportional to the area under the blood concentration curve for compound K in their blood samples. These metabolites such as compound K exhibit potent pharmacological effects, such as antitumor, anti-inflammatory, antidiabetic, antiallergic, and neuroprotective effects compared with the parent ginsenosides, such as Rb1, Rb2, and Re. Therefore, to monitor the potent pharmacological effects of ginseng, a novel probiotic fermentation technology has been developed to produce absorbable and bioactive metabolites. Based on these findings, it is concluded that gut microbiota play an important role in the pharmacological action of orally administered ginseng, and probiotics that can replace gut microbiota can be used in the development of beneficial and bioactive ginsengs.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.84.2-84.2
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• 2008

• 생명과학회지
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• 제27권11호
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• pp.1290-1298
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• 2017

인체의 장내에 존재하는 장내 미생물은 서로 공생 또는 길항 관계를 유지하며 우리 몸의 면역 방어 기전에 중요한 요소로 작용한다. 본 연구는 항암제가 위암 환자의 장내 미생물 생태계에 미치는 영향을 조사 하였다. 항암치료를 받는 환자의 분변에서 genomic DNA를 추출하고, 16S rDNA 유전자에 대한 denaturing gradient gel electrophoresis (DGGE)를 수행하였다. 분석된 균주는 개체간의 차이가 있었으나, 대부분 사람의 장내에 살고 있는 normal flora로 동정되었다. 모든 분변에 존재하는 5 개 밴드의 서열 분석 결과에 의하면 Faecalibacterium prausnitzii, Morganella morganii 및 Uncultured bacterium sp.가 나타났고, 항암제 처리 후 Sphingomonas paucimobilis, Lactobacillus gasseri, Parabacteroides distasonis 및 Enterobacter sp.가 증가하였다. 이 연구에서 probiotic으로 알려진 Bifidobacterium과 Lactobacillus를 특이적 PCR primer를 이용하여 동정한 결과, 항암제 투여로 인해 Bifidobacterium과 Lactobacillus의 개체군이 현저하게 줄어들어 diarrhea와 같은 부작용의 원인을 예상하게 하며, 장내 생태계의 주요 박테리아 집단에도 중요한 영향을 미치는 것을 알 수 있었다. 이러한 결과는 항암제 투여와 같이 시간의 흐름에 따른 균총의 변화를 시각적으로 모니터링하기 위하여 PCR-DGGE 분석법이 유용하다는 것을 나타낸다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제21권4호
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• pp.219-233
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• 2018

Helicobacter pylori plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease, gastric cancer, and gastric mucosa-associated lymphoid tissue lymphoma. In Korea, the guidelines for the diagnosis and treatment of H. pylori infection in adults were revised in 2013. The European Helicobacter and Microbiota Study Group and Consensus panel released the fifth edition of the Maastricht Consensus Report for the management of H. pylori infection in 2015, and the European Society of Paediatric Gastroenterology, Hepatology and Nutrition and the North American Society of Paediatric Gastroenterology, Hepatology and Nutrition released the updated joint guidelines for children and adolescents in 2016. Considering these recommendations and recent progress in our research and that of other research teams, this study aimed to discuss the diagnostic strategies for H. pylori infection in children and adolescents.

• 한국축산식품학회지
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• 제43권5호
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• pp.751-766
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• 2023

Helicobacter pylori is a bacterium that naturally thrives in acidic environments and has the potential to induce various gastrointestinal disorders in humans. The antibiotic therapy utilized for treating H. pylori can lead to undesired side effects, such as dysbiosis in the gut microbiota. The objective of our study was to explore the potential antibacterial effects of nisin and lactic acid (LA) in yogurt against H. pylori. Additionally, we investigated the anti-inflammatory effects of nisin and LA in human gastric (AGS) cells infected with H. pylori. Nisin and LA combination showed the strongest inhibitory activity, with confirmed synergy at 0.375 fractional inhibitory concentration index. Also, post-fermented yogurt with incorporation of nisin exhibited antibacterial effect against H. pylori. The combination of nisin and LA resulted in a significant reduction of mRNA levels of bacterial toxins of H. pylori and pro-inflammatory cytokines in AGS cells infected with H. pylori. Furthermore, this also increased bacterial membrane damage, which led to DNA and protein leakage in H. pylori. Overall, the combination of nisin and LA shows promise as an alternative therapy for H. pylori infection. Additionally, the incorporation of nisin into foods containing LA presents a potential application. Further studies, including animal research, are needed to validate these findings and explore clinical applications.

• Journal of Dairy Science and Biotechnology
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• 제34권2호
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• pp.75-82
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• 2016

Members of the genus Bifidobacterium are prevalent in the human colon and represent up to 90% of all bacteria in fecal samples of breast-fed infants, and 3~5% of adult fecal microbiota. Bifidobacteria produce organic acids, thus reducing the colon pH to a level inhibitory for pathogenic bacteria. They can also detoxify a number of toxic compounds and adhere to the colon mucosa, thus preventing the adherence of pathogens and induction of colon cancer. Recently, we identified a novel Bifidobacterium longum subsp. longum strain, KACC 91563, in a fecal sample of a Korean neonate, and demonstrated its functional properties. We showed that B. longum KACC 91563 alleviates food allergy through mast cell suppression and produces antioxidative and antihypertensive peptides by casein hydrolysis. Dairy products are considered as an ideal food system for the delivery of probiotic cultures to the human gastrointestinal tract. Cheese affords protection to probiotic microbes during gastric transit due to its relatively high pH, more solid consistency, higher fat content, and higher buffering capacity. Incorporation of B. longum KACC 91563 into cheese making is currently under study.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1870-1875
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• 2020

Probiotics are often infused into functional foods or encapsulated in a supplement form to maintain a healthy balance between the gut microbiota and their host. Because there are milk-based functional foods such as yogurt and cheese on the market, it has been suggested that milk-based probiotics could be incorporated into skim milk proteins in a liquid capsule. Skim milk is mainly composed of casein and whey protein, which create a strong natural barrier and can be used to encapsulate probiotics. In this study, we compared the encapsulated probiotics prepared with milk-based concentrated cell mixtures using commercial probiotics. Probiotic capsules were emulsified with skim milk proteins using vegetable oil to form a double coating layer. The product was heat-stable when tested using a rheometer. The survival rate of the milk-based probiotic cells in the lower gastric environment with bile was significantly higher than commercial probiotics. Thus, milk-encapsulated probiotics exhibited greater efficacy in the host than other types of probiotics, suggesting that the former could be more viable with a longer shelf life under harsh conditions than other form of probiotics. Our findings suggested that, compared with other types of probiotics, milk-based probiotics may be a better choice for producers and consumers.