• BMB Reports
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• v.57 no.5
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• pp.207-215
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• 2024

The gut microbiota, an intricate community of bacteria residing in the gastrointestinal system, assumes a pivotal role in various physiological processes. Beyond its function in food breakdown and nutrient absorption, gut microbiota exerts a profound influence on immune and metabolic modulation by producing diverse gut microbiota-generated metabolites (GMGMs). These small molecules hold potential to impact host health via multiple pathways, which exhibit remarkable diversity, and have gained increasing attention in recent studies. Here, we elucidate the intricate implications and significant impacts of four specific metabolites, Urolithin A (UA), equol, Trimethylamine N-oxide (TMAO), and imidazole propionate, in shaping human health. Meanwhile, we also look into the advanced research on GMGMs, which demonstrate promising curative effects and hold great potential for further clinical therapies. Notably, the emergence of positive outcomes from clinical trials involving GMGMs, typified by UA, emphasizes their promising prospects in the pursuit of improved health and longevity. Collectively, the multifaceted impacts of GMGMs present intriguing avenues for future research and therapeutic interventions.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2002.10a
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• pp.98-98
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• 2002

• Journal of Microbiology
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• v.45 no.5
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• pp.394-401
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• 2007

In this study, bacterial communities within the guts of several longicorn beetles were investigated by a culture-dependent method. A total of 142 bacterial strains were isolated from nine species of longicorn beetle, including adults and larvae. A comparison of their partial 16S rRNA gene sequences showed that most of the bacteria constituting the gut communities can typically be found in soil, plants and the intestines of animals, and approximately 10% were proposed as unreported. Phylogenetic analysis demonstrated that the bacterial species comprised 7 phyla, and approximately half were Gammaproteobacteria. Actinobacteria were the second most populous group (19%), followed by Firmicutes (13%) and Alphaproteobacteria (11%). Betaproteobacteria, Flavobacteria, and Acidobacteria were minor constituents. The taxonomic compositions of the isolates were variable according to the species of longicorn beetle. Particularly, an abundance of Actinobacteria existed in Moechotypa diphysis and Mesosa hirsute, which eat broadleaf trees; however, no Actinobacteria were isolated from Corymbia rubra and Monochamus alternatus, which are needle-leaf eaters. Considerable proportions of xylanase and pectinase producing bacteria in the guts of the longicorn beetles implied that the bacteria may play an important role in the digestion of woody diets. Actinobacteria and Gammaproteobacteria were the dominant xylanase producers in the guts of the beetles.

• Journal of Animal Science and Technology
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• v.64 no.6
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• pp.1184-1198
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• 2022

In this study, Rubus coreanus (R. coreanus) byproducts with high polyphenol content were fermented with R. coreanus-derived lactic acid bacteria (Lactobacillus plantarum GBL 16 and 17). Then the effect of R. coreanus-derived lactic acid bacteria fermented feed (RC-LAB fermented feed) with probiotics (Bacillus subtills, Aspergillus oryzae, Yeast) as a feed additive for pigs on the composition of intestinal microbes and the regulation of intestinal immune homeostasis was investigated. Seventy-two finishing Berkshire pigs were randomly allotted to four different treatment groups and 18 replicates. RC-LAB fermented feed with probiotics increased the genera Lactobacillus, Streptococcus, Mitsuokella, Prevotella, Bacteroides spp., Roseburia spp., and Faecalibacterium prausnitzii, which are beneficial bacteria of the digestive tract of pigs. Also, RC-LAB fermented feed with probiotics decreased the genera Clostridium, Terrisporobacter, Romboutsia, Kandleria, Megasphaera and Escherichia, which are harmful bacteria. In particular, the relative abundance of the genera Lactobacillus and Streptococcus increased by an average of 8.51% and 4.68% in the treatment groups and the classes Clostridia and genera Escherichia decreased by an average of 27.05% and 2.85% in the treatment groups. In mesenteric lymph nodes (MLN) and spleens, the mRNA expression of transcription factors and cytokines in Th1 and Treg cells increased and the mRNA expression of Th2 and Th17 transcription factors and cytokines decreased, indicating a regulatory effect on intestinal immune homeostasis. RC-LAB fermented feed regulates gut immune homeostasis by influencing the composition of beneficial and detrimental microorganisms in the gut and regulating the balance of Th1/Th2 and Th17/Treg cells.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.295-304
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• 2023

Synbiotics help to improve gut health by promoting the growth of beneficial bacteria while glyconutrients provide a source of energy for the gut bacteria and may also have immunemodulating effects. The aim of the present study was to assess the effect of this combination on fatty acid and meat quality characteristics of growing pigs. In a five-week experiment, 804 growing three-way crossbred ([Landrace × Yorkshire] × Duroc) pigs with an initial body weight of 31.90 ± 2.6 kg on average were assigned to two treatments: 1) CON (basal diet) and 2) TRT1 (basal diet + 0.3% glycozyme [synbiotics and glyconutrient]), each consisting of 402 pigs. The TRT1 groups showed significantly higher values of palmitoleic acid (C16:1), capric acid (C10:0), myristic acid (C14:0), lauric acid (C12:0), elaidic acid (C18:1, t), pentadecylic acid (C15:0), gondoic acid (C20:1), lignoceric acid (C24:0), and omega-6 : omega-3 in fat than the CON groups. Moreover, in the lean tissues of the pig, the levels of C12:0, C14:0, C17:0, and C20:1 were significantly higher in TRT1 than in CON. However, significant differences were not observed after glycozyme addition in pH, water holding capacity, cooking loss, longissimus muscle area, drip loss, meat color, and sensory evaluation parameters. To conclude, the positive results of the fatty acid composition indicate that glycozyme may be an effective pig feed additive.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.713-725
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• 2018

Lower termites require symbiotic microbes in their gut. The microbial communities in the termites must adapt to the termite temperature. Reticulitermes speratus KMT001 from Bukhan Mountain in Seoul may require a special symbiotic microorganisms for growth in low temperature Korean habitat. A metagenomics analysis showed a dramatic change in the symbiotic bacterial flora in the gut of R. speratus KMT001 in response to low temperatures of $4^{\circ}C$ or $10^{\circ}C$. Elusimicrobia, which are endosymbionts of flagellate protists, is the dominant phylum in the termite gut at ${\geq}15^{\circ}C$ but its population decreased drastically at low temperature. Four representative bacterial strains isolated from R. speratus KMT001 in a previous study produced maximum ${\beta}$-glucosidase levels within the temperature range of $10^{\circ}C-30^{\circ}C$. Elizabethkingia sp. BM10 produced ${\beta}$-glucosidase specifically at $10^{\circ}C$. This strain supported the existence of symbiotic bacteria for the low temperature habitat of the termite. This identified bacterium will be a resource for studying low temperature adaptation of termites, studying the gene expression at low temperatures, and developing an industrial cellulase at low temperature.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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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.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1491-1499
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• 2018

Objective: This study was designed to investigate the effects of an Aspergillus sulphureus xylanase expressed in Pichia pastoris on the growth performance, nutrient digestibility and gut microbes in weanling pigs. Methods: A total of 180 weanling pigs (initial body weights were $8.47{\pm}1.40kg$) were assigned randomly to 5 dietary treatments. Each treatment had 6 replicates with 6 pigs per replicate. The experimental diets were wheat based with supplementation of 0, 500, 1,000, 2,000, and 4,000 U xylanase/kg. The experiment lasted 28 days (early phase, d 0 to 14; late phase, d 15 to 28). Results: In the early phase, compared to the control, average daily gain (ADG) was higher for pigs fed diets supplemented with xylanase and there was a quadratic response in ADG (p<0.05). In the entire phase, ADG was higher for the pigs fed 1,000 or 2,000 U/kg xylanase compared to the control (p<0.05). The gain to feed ratio was higher for pigs fed diets supplemented with 1,000 or 2,000 U/kg xylanase compared to the control (p<0.05). Increasing the amount of xylanase improved the apparent total tract digestibility of dry matter, crude protein, neutral detergent fiber, calcium, and phosphorus during both periods (p<0.05). Xylanase supplementation (2,000 U/kg) decreased the proportion of Lachnospiraceae (by 50%) in Firmicutes, but increased Prevotellaceae (by 175%) in Bacteroidetes and almost diminished Enterobacteriaceae (Escherichia-Shigella) in Proteobacteria. Conclusion: Xylanase supplementation increased growth performance and nutrient digestibility up to 2,000 U/kg. Supplementation of xylanase (2,000 U/kg) decreased the richness of gut bacteria but diminished the growth of harmful pathogenic bacteria, such as Escherichia-Shigella, in the colon.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.1
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• pp.11-19
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• 2018

The gut microbiome has been studied extensively over the past decade with most scientific reports focused on the adverse role of the gut microbiome on gastrointestinal diseases. For example, the altered gut microbiome exacerbates the development of immune system-mediated damage in many diseases. The most studied pathologies include irritable bowel syndrome, inflammatory bowel diseases, and colitis-associated cancer. On the other hand, intestinal microflora is also beneficial and contributes to the intestinal physiology by the synthesis of vitamins, production of short chain fatty acids and bile acid metabolism, thereby maintaining gut homeostasis. Therefore, the balance between commensal and pathogenic bacteria populations influences mainly the maintenance of intestinal health. Changes in the intestinal microflora have been suspected to be the underlying causes of multiple diseases. Despite the immense amount of published data, the optimal gut microbiome composition is still controversial. This review briefly outlines the connection between the gut microbiome and critical gastrointestinal diseases focusing on three prominent intestinal disorders: irritable bowel syndrome, inflammatory bowel diseases, and colitis-associated cancer disorders. Finally, intervention strategies using natural products for the alleviation of these diseases and the maintenance of a health gut microbiome are suggested.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.78-84
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• 2017

Objective: The aim of this study was to examine shifts in the composition of the bacterial population in the intestinal tracts (ITs) of weaning piglets by antibiotic treatment using high-throughput sequencing. Methods: Sixty 28-d-old weaning piglets were randomly divided into two treatment groups. The Control group was treated with a basal diet without antibiotics. The Antibiotic group's basal diet contained colistin sulfate at a concentration of 20 g per ton and bacitracin zinc at a concentration of 40 g per ton. All of the pigs were fed for 28 days. Then, three pigs were killed, and the luminal contents of the jejunum, ileum, cecum, and colon were collected for DNA extraction and high-throughput sequencing. Results: The results showed that the average daily weight gain of the antibiotic group was significantly greater (p<0.05), and the incidence of diarrhea lower (p>0.05), than the control group. A total of 812,607 valid reads were generated. Thirty-eight operational taxonomic units (OTUs) that were found in all of the samples were defined as core OTUs. Twenty-one phyla were identified, and approximately 90% of the classifiable sequences belonged to the phylum Firmicutes. Forty-two classes were identified. Of the 232 genera identified, nine genera were identified as the core gut microbiome because they existed in all of the tracts. The proportion of the nine core bacteria varied at the different tract sites. A heat map was used to understand how the numbers of the abundant genera shifted between the two treatment groups. Conclusion: At different tract sites the relative abundance of gut microbiota was different. Antibiotics could cause shifts in the microorganism composition and affect the composition of gut microbiota in the different tracts of weaning piglets.