• Korean Journal of Clinical Laboratory Science
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• v.56 no.1
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• pp.59-65
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• 2024

This study examined the fecal samples of striped field mice (Apodemus agrarius coreae) captured in Jeju Special Self-Governing Province. Fecal samples, including the colon and other intestinal organs, were collected and subjected to aerobic culture to investigate the distribution of intestinal microorganisms. Gram staining of the aerobic cultured bacterial colonies from 36 fecal samples revealed the predominant presence of gram-negative bacilli in all samples. Among the 36 samples, gram-negative bacilli were identified in 36 strains (100%), gram-positive cocci in 21 strains (58.3%), and gram-positive bacilli in 15 strains (41.7%), while no gram-negative cocci were observed. The gram-negative bacilli cultured from the 36 samples were identified using the Vitek 2 system, and all were determined to be Escherichia coli (E. coli) strains. In addition, one sample was concurrently identified with E. coli and Enterobacter cloacae strains. The antimicrobial susceptibility testing for the identified E. coli strains did not include all antibiotics, but one strain exhibited intermediate resistance to cefoxitin. No pathogenic bacteria were present in the fecal samples of the scrub typhus-infected rodents, which are vectors for chigger-borne diseases affecting humans and animals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48
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• pp.58-64
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• 2003

To enjoy a healthy life, it is important to have a well-balanced diet. However, in today's society, there is an increase in the consumption of preprocessed foods and frequency of eating out. Also the western diet, which is becoming move popular worldwide, contains relatively high levels of protein and fat, and a low amount of fiber, Furthermore, the increased availability of favorite foods has created a condition were the individual diet is less variable. With these conditions, it is difficult to maintain a diet that is nutritionally balanced. With these unbalanced diets, which are difficult to change, there has been an increase in adult disease and health problems, such as colon and breast cancer, It is speculated that metabolites for carcinogens are produced from diet components and that intestinal bacteria contribute to the production of these metabolites. Therefore, it is necessary to evaluate the relationships between health, diet, and intestinal microflora. Soybean oligosaccharide is composed of water-soluble saccharides that have been extracted from soybean whey, a by-product from the production of soy protein. This is mainly a mixture of mono-, di-, tri-, and tetrasac-charides, with the principle components being the oligosaccharide raffinose and stachyose. When consumed by humans, the oligosaccharides cannot be digested in the human duodenal and small intestinal mucosa, and these are selectively utilized by beneficial bifidobacteria in intestines. The results of acute and subacute toxicity tests, soy-bean oligosaccharides were nonpoisonous. Soybean oligosaccharides promote the growth of indigenous bifido-bacteria in the colon which by their antagonistic effects, suppress the activity of putrefactive bacteria. Also, they reduce toxic metabolites, detrimental enzymes and plasma lipid, and increase in the frequency of bowel evacuation and fecal quantities. Consequently, soybean oligosaccharides as functional foods components have potential roles in the prevention and medical treatment of chronic adult diseases. The study of processing property and physiological function of soybean oligosacchavides and development of high oligosaccharide variety allow the creation of new and exciting foodstuffs that aye functional healthy.

• IMMUNE NETWORK
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• v.14 no.1
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• pp.38-44
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• 2014

K/BxN serum can transfer arthritis to normal mice owing to the abundant autoantibodies it contains, which trigger innate inflammatory cascades in joints. Little is known about whether gut-residing microbes affect host susceptibility to autoantibody-mediated arthritis. To address this, we fed C57BL/6 mice with water containing a mixture of antibiotics (ampicillin, vancomycin, neomycin, and metronidazol) for 2 weeks and then injected them with K/BxN serum. Antibiotic treatment significantly reduced the amount of bacterial genomic DNA isolated from fecal samples, in particular a gene encoding 16S ribosomal RNA derived from segmented filamentous bacteria. Arthritic signs, as indicated by the arthritic index and ankle thickness, were significantly attenuated in antibiotic-treated mice compared with untreated controls. Peyer's patches and mesenteric lymph nodes from antibiotic-treated mice contained fewer IL-17-expressing cells than those from untreated mice. Antibiotic treatment reduced serum C3 deposition in vitro via the alternative complement pathway. IL-$17^{-/-}$ congenic C57BL/6 mice were less susceptible to K/BxN serum-transferred arthritis than their wild-type littermates, but were still responsive to treatment with antibiotics. These results suggest that gut-residing microbes, including segmented filamentous bacteria, induce IL-17 production in GALT and complement activation via the alternative complement pathway, which cause the host to be more susceptible to autoantibody-mediated arthritis.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1510-1518
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• 2015

In this work, we wanted to develop a probiotic from famous longevity villages in Korea. We visited eight longevity villages in Korea to collect fecal samples from healthy adults who were aged above 80 years and had regular bowel movements, and isolated lactic-acid-producing bacteria from the samples. Isolated colonies that appeared on MRS agar containing bromophenol blue were identified by means of 16S rRNA sequencing, and 102 of the isolates were identified as lactic-acid-producing bacteria (18 species). Lactobacillus fermentum was the most frequently found species. Eight isolates were selected on the basis of their ability to inhibit the growth of six intestinal pathogens (Escherichia coli O157:H7, Salmonella enterica subsp. enterica Typhimurium, Salmonella enterica subsp. enterica Enteritidis, Enterococcus faecalis, Staphylococcus aureus, and Listeria monocytogenes) and their susceptibility to 15 antimicrobial agents. Among these eight isolates, four Lactobacillus fermentum isolates were found not to produce any harmful enzymes or metabolites. Among them, Lactobacillus fermentum isolate no. 24 showed the strongest binding to intestinal epithelial cells, the highest immune-enhancing activity, anti-inflammation activity, and anti-oxidation activity as well as the highest survival rates in the presence of artificial gastric juice and bile solution. This isolate, designated Lactobacillus fermentum PL9988, has all the characteristics for a good probiotic.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.161-166
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• 2004

The effects of kimchis intake on Helicobacter pylori infection in the stomach, the counts of lactic acid bacteria in the large intestine, and bacterial enzymes ($\beta$-glucosidase, $\beta$-glucuronidase) and pH in feces were examined. A total of 20 participants (age range 34 ∼ 57) were assessed for H. pylori infection status by Be urea breath test. Fourteen participants were eliminated because they were H. pylori-negative. This study consisted of 4 consecutive phase, each of which lasted 4 weeks. Three hundred grams of kimchi were administered to H. pylori-infected subjects during the kimchi phase, followed by 4 weeks of control phase. During the control phase, subjects consumed 60 g of kimchi, the minimum amount in their customary diets. All participants were found to be H. pylori-positive during all experimental periods. During the kimchi phase, delta over baseline (DOB) level was lower than during the control phase, although significant difference between the kimchi and control phases were not found (p=0.9439). However, the counts of Lactobacillus sp. and Leuconostoc sp. significantly (p < 0.0005) increased during the kimchi phase. $\beta$-Glucosidase and $\beta$-glucuronidase activities and pH were significantly decreased by kimchi intake compared to control (p=0.000l). These results suggested that kimchi consumption did not show any therapeutic effect on H. pylori in the stomach. However, kimchi seemed to be a good food for colon health, since it increased the beneficial bacteria such as lactobacillus and decreased toxic enzyme ($\beta$-glucosidase and $\beta$-glucuronidase) activity and pH.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.269-273
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• 2005

Five dibenzylbutyrolactones were isolated from a methanol extract of Arctii fructus (Arctium lappa L.) by bioassay-guided isolation, using the interleukin-l $\beta$ converting enzyme (caspase-l, ICE) production inhibitory assay in vitro. These compounds were spectroscopically identified as lappaol E (1), lappaol A (2), matairesinol (3), arctigenin (4), and arctiin (5). Among the compounds tested, arctigenin (4) showed the strongest inhibitory activity for ICE production in IL-$\beta$-induced proliferation of D 1 OS cells. Western blot analysis demonstrated that the arctigenin suppressed the expression of ICE protein in a dose-dependent manner. To estimate the biotransformation of Arctii fructus in vivo by human intestinal bacteria, we carried out an anaerobic incubation of the Arctii fructus extract with a human fecal suspension. From the HPLC analysis of metabolites, Arctiin (IC$_{50}$=74.2$\mu$g/ml), a major component of Arctii fructus, was transformed to aglycone, arctigenin (IC$_{50}$=12.5$\mu$g/ml), by human intestinal bacteria. The ICE production inhibitory activity of Arctii fructus would be much stronger in vivo than in vitro due to the biotransformation by human intestinal bacteria.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1321-1334
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• 2020

Beef, pork, chicken and milk are considered representative protein sources in the human diet. Since the digestion of protein is important, the role of intestinal microflora is also important. Despite this, the pure effects of meat and milk intake on the microbiome are yet to be fully elucidated. To evaluate the effect of beef, pork, chicken and milk on intestinal microflora, we observed changes in the microbiome in response to different types of dietary animal proteins in vitro. Feces were collected from five 6-week-old pigs. The suspensions were pooled and inoculated into four different media containing beef, pork, chicken, or skim milk powder in distilled water. Changes in microbial communities were analyzed using 16S rRNA sequencing. The feces alone had the highest microbial alpha diversity. Among the treatment groups, beef showed the highest microbial diversity, followed by pork, chicken, and milk. The three dominant phyla were Proteobacteria, Firmicutes, and Bacteroidetes in all the groups. The most abundant genera in beef, pork, and chicken were Rummeliibacillus, Clostridium, and Phascolarctobacterium, whereas milk was enriched with Streptococcus, Lactobacillus, and Enterococcus. Aerobic bacteria decreased while anaerobic and facultative anaerobic bacteria increased in protein-rich nutrients. Functional gene groups were found to be over-represented in protein-rich nutrients. Our results provide baseline information for understanding the roles of dietary animal proteins in reshaping the gut microbiome. Furthermore, growth-promotion by specific species/genus may be used as a cultivation tool for uncultured gut microorganisms.

• Journal of Radiation Protection and Research
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• v.45 no.4
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• pp.163-170
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• 2020

Background: Gut microflora contributes to the nutritional metabolism of the host and to strengthen its immune system. However, if the intestinal barrier function of the living body is destroyed by radiation exposure, the intestinal bacteria harm the health of the host and cause sepsis. Therefore, this study aims to trace short-term radiation-induced changes in the mouse gut microflora-dominant bacterial genus, and analyze the degree of intestinal epithelial damage. Materials and Methods: Mice were irradiated with 0, 2, 4, 8 Gy X-rays, and the gut microflora and intestinal epithelial changes were analyzed 72 hours later. Five representative genera of Actinobacteria, Firmicutes, and Bacteroidetes were analyzed in fecal samples, and the intestine was pathologically analyzed by Hematoxylin-Eosin and Alcian blue staining. In addition, DNA fragmentation was evaluated by the TdT-mediated dUTP nick-end labeling (TUNEL) assay. Results and Discussion: The small intestine showed shortened villi and reduced number of goblet cells upon 8 Gy irradiation. The large intestine epithelium showed no significant morphological changes, but the number of goblet cells were reduced in a radiation dose-dependent manner. Moreover, the small intestinal epithelium of 8 Gy-irradiated mice showed significant DNA damaged, whereas the large intestine epithelium was damaged in a dose-dependent manner. Overall, the large intestine epithelium showed less recovery potential upon radiation exposure than the small intestinal epithelium. Analysis of the intestinal flora revealed fluctuations in lactic acid bacteria excretion after irradiation regardless of the morphological changes of intestinal epithelium. Altogether, it became clear that radiation exposure could cause an immediate change of their excretion. Conclusion: This study revealed changes in the intestinal epithelium and intestinal microbiota that may pave the way for the identification of novel biomarkers of radiation-induced gastrointestinal disorders and develop new therapeutic strategies to treat patients with acute radiation syndrome.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1144-1172
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• 2022

Salmonella enterica serovar Typhimurium isolate HJL777 is a virulent bacterial strain in pigs. The high rate of salmonella infection are at high risk of non-typhoidal salmonella gastroenteritis development. Salmonellosis is most common in young pigs. We investigated changes in gut microbiota and biological function in piglets infected with salmonella via analysis of rectal fecal metagenome and intestinal transcriptome using 16S rRNA and RNA sequencing. We identified a decrease in Bacteroides and increase in harmful bacteria such as Spirochaetes and Proteobacteria by microbial community analysis. We predicted that reduction of Bacteroides by salmonella infection causes proliferation of salmonella and harmful bacteria that can cause an intestinal inflammatory response. Functional profiling of microbial communities in piglets with salmonella infection showed increasing lipid metabolism associated with proliferation of harmful bacteria and inflammatory responses. Transcriptome analysis identified 31 differentially expressed genes. Using gene ontology and Innate Immune Database analysis, we identified that BGN, DCN, ZFPM2 and BPI genes were involved in extracellular and immune mechanisms, specifically salmonella adhesion to host cells and inflammatory responses during infection. We confirmed alterations in gut microbiota and biological function during salmonella infection in piglets. Our findings will help prevent disease and improve productivity in the swine industry.

• Journal of Animal Science and Technology
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• v.65 no.3
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• pp.611-626
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• 2023

Escherichia coli (E. coli) and Salmonella enterica (SE) infections in pigs are major source associated with enteric disease such as post weaning diarrhea. The aim of this study was to investigate the effects of Pediococcus pentosaceus in weaned piglets challenged with pathogen bacteria. In Experiment.1 90 weaned piglets with initial body weights of 8.53 ± 0.34 kg were assigned to 15 treatments for 2 weeks. The experiments were conducted two trials in a 2 × 5 factorial arrangement of treatments consisting of two levels of challenge (challenge and non-challenge) with E. coli and SE, respectively and five levels of probiotics (Control, Lactobacillus plantarum [LA], Pediococcus pentosaceus SMFM2016-WK1 [38W], Pediococcus acidilactici K [PK], Lactobacillus reuteri PF30 [PF30]). In Experiment.2 a total of 30 weaned pigs (initial body weight of 9.84 ± 0.85 kg) were used in 4 weeks experiment. Pigs were allocated to 5 groups in a randomized complete way with 2 pens per group and 3 pigs per pen. Supplementation of LA and 38W improved (p < 0.05) growth performance, intestinal pathogen bacteria count, fecal noxious odor and diarrhea incidence. In conclusion, supplementation of 38W strains isolated from white kimchi can act as probiotics by inhibiting E. coli and SE.