• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1409-1419
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• 2021

A growing number of healthy dietary ingredients in fruits and vegetables have been shown to exhibit diverse biological activities. Phloretin, a dihydrochalcone flavonoid that is abundant in apples and pears, has anti-inflammatory effects on ulcerative colitis (UC) mice. The gut microbiota and metabolism are closely related to each other due to the existence of the food-gut axis in the human colon. To investigate the interplay of faecal metabolites and the microbiota in UC mice after phloretin treatment, phloretin (60 mg/kg) was administered by gavage to ameliorate dextran sulfate sodium (DSS)-induced UC in mice. Gut microbes and faecal metabolite profiles were detected by high-throughput sequencing and liquid chromatography mass spectrometry (LC-MS) analysis, respectively. The correlations between gut microbes and their metabolites were evaluated by Spearman correlation coefficients. The results indicated that phloretin reshaped the disturbed faecal metabolite profile in UC mice and improved the metabolic pathways by balancing the composition of faecal metabolites such as norepinephrine, mesalazine, tyrosine, 5-acetyl-2,4-dimethyloxazole, and 6-acetyl-2,3-dihydro-2-(hydroxymethyl)-4(1H)-pyridinone. Correlation analysis identified the relations between the gut microbes and their metabolites. Proteus was negatively related to many faecal metabolites, such as norepinephrine, L-tyrosine, laccarin, dopamine glucuronide, and 5-acetyl-2,4-dimethyloxazole. The abundance of unidentified Bacteriodales_S24-7_group was positively related to ecgonine, 15-KETE and 6-acetyl-2,3-dihydro-2-(hydroxymethyl)-4(1H)-pyridinone. The abundance of Christensenellaceae_R-7_group was negatively related to the levels of 15-KETE and netilmicin. Stenotrophomonas and 15-KETE were negatively related, while Intestinimonas and alanyl-serine were positively related. In conclusion, phloretin treatment had positive impacts on faecal metabolites in UC mice, and the changes in faecal metabolites were closely related to the gut microbiota.

• Biomedical Science Letters
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• v.23 no.3
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• pp.166-174
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• 2017

The bacterial cells located within the gastrointestinal tract (GIT) outnumber the host's cells by a factor of ten. These human digestive-tract microbes are referred to as the gut microbiota. During the last ten years, our understanding of gut microbiota composition and its relation with intra- and extra-intestinal diseases including risk factors of cardiovascular diseases (CVD) such as atherosclerosis and metabolic syndrome, have greatly increased. A question which frequently arises in the research community is whether one can modulate the gut microbial environment to 'control' risk factors in CVD. In this review, we summarized promising intervention methods, based on our current knowledge of intestinal microbiota in modulating CVD. Furthermore, we explore how gut microbiota can be therapeutically exploited by targeting their metabolic program to control pathologic factors of CVD.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.2
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• pp.45-53
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• 2019

The popularity of keeping stag beetles (Dorcus titanus castanicolor Motschulsky 1861, Coleoptera: Lucanidae) as pets has increased. Consistent with the rise in the number of insect farms using these beetles, the number of contaminated or diseased D. titanus castanicolor has also increased. This investigation was conducted to analyze the cause of D. titanus castanicolor disease. The contaminated larvae of D. titanus castanicolor showed Allomyrina nudivirus infection symptoms similar to those of Allomyrina nudivirus infection. However, the disease carried by of D. titanus castanicolor is not derived from the virus infecting Allomyrina, as determined by PCR. Our study revealed that the major gut microbes of infectious D. titanus castanicolor belonged to the phylum Proteobacteria, and specifically, Pseudomonas knackmussi (Symptom 1 - 39.62% to Symptom 2 - 41.50% to Symptom 3 - 76.76% as the disease progressed severely) and Citrobacter koseri (Symptom 1 - 1.48% to Symptom 2 - 6.04% to Symptom 3 - 6.16% as the disease progressed severely) were detected. Additionally, a high proportion of larvae from the uninfected group were found to harbor bacteria belonging to the phylum Firmicutes (72%). However, as the disease progressed severely in these beetles, the proportion of Firmicutes decreased (Symptom 1 - 72.03% to Symptom 2 - 44.7% to Symptom 3 - 26.3%). These findings imply that colonization by Firmicutes was inversely proportional to Proteobacteria colonization in the gut. This was found to be true for both the normal and disease conditions of D. titanus castanicolor. In this study, we examined the distribution of intestinal microbial communities in normal and contaminated larvae. We observed a correlation between these contaminated microbes and the overall health of the beetle, and our findings suggest that there may be a link between disease progression and the gut microbiome.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.155-173
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• 2011

Humans have and hold 100 trillion intestinal bacteria that are essential for health. For millions of years human-microorganisms interaction has co-evolved, and maintained close symbiotic relationship. Gut bacteria contributes to human health and metabolism, and humans provides the optimum nutrition-rich environment for bacteria. What is the mechanism of the host distinguishing the intestinal bacteria as its cohabiting partner and what kind of benefits does the gut microbiota provide the human are the fundamental questions to be asked and solved in order to make human life a higher quality. This review explains the physiological relationship and mutualism between the host and gut microorganism, and highlights the potential therapeutic approach for treating diseases, maintaining and improving health based on these correlations.

• 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.

• IMMUNE NETWORK
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• v.15 no.1
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• pp.1-8
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• 2015

Innate immune cells survey antigenic materials beneath our body surfaces and provide a front-line response to internal and external danger signals. Dendritic cells (DCs), a subset of innate immune cells, are critical sentinels that perform multiple roles in immune responses, from acting as principal modulators to priming an adaptive immune response through antigen-specific signaling. In the gut, DCs meet exogenous, non-harmful food antigens as well as vast commensal microbes under steady-state conditions. In other instances, they must combat pathogenic microbes to prevent infections. In this review, we focus on the function of intestinal DCs in maintaining intestinal immune homeostasis. Specifically, we describe how intestinal DCs affect IgA production from B cells and influence the generation of unique subsets of T cell.

• IMMUNE NETWORK
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• v.23 no.1
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• pp.7.1-7.27
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• 2023

The mammalian intestines harbor trillions of commensal microorganisms composed of thousands of species that are collectively called gut microbiota. Among the microbiota, bacteria are the predominant microorganism, with viruses, protozoa, and fungi (mycobiota) making up a relatively smaller population. The microbial communities play fundamental roles in the maturation and orchestration of the immune landscape in health and disease. Primarily, the gut microbiota modulates the immune system to maintain homeostasis and plays a crucial role in regulating the pathogenesis and pathophysiology of inflammatory, neuronal, and metabolic disorders. The microbiota modulates the host immune system through direct interactions with immune cells or indirect mechanisms such as producing short-chain acids and diverse metabolites. Numerous researchers have put extensive efforts into investigating the role of microbes in immune regulation, discovering novel immunomodulatory microbial species, identifying key effector molecules, and demonstrating how microbes and their key effector molecules mechanistically impact the host immune system. Consequently, recent studies suggest that several microbial species and their immunomodulatory molecules have therapeutic applicability in preclinical settings of multiple disorders. Nonetheless, it is still unclear why and how a handful of microorganisms and their key molecules affect the host immunity in diverse diseases. This review mainly discusses the role of microbes and their metabolites in T helper cell differentiation, immunomodulatory function, and their modes of action.

• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.757-764
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• 2024

Despite considerable advancements achieved using next-generation sequencing technologies in exploring microbial diversity, several species of the gut microbiome remain unknown. In this transformative era, culturomics has risen to prominence as a pivotal approach in unveiling realms of microbial diversity that were previously deemed inaccessible. Utilizing innovative strategies to optimize growth and culture medium composition, scientists have successfully cultured hard-tocultivate microbes. This progress has fostered the discovery and understanding of elusive microbial entities, highlighting their essential role in human health and disease paradigms. In this review, we emphasize the importance of culturomics research on the gut microbiome and provide new theories and insights for expanding microbial diversity via the optimization of cultivation conditions.

• Journal of Applied Biological Chemistry
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• v.62 no.2
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• pp.211-217
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• 2019

Dietary pattern has paramount importance in shaping the gut microbiota and its associated host health. Herein this study, long term (12 weeks) impact of mushroom derived dietary fiber, ${\beta}-glucan$, is investigated for its effect on low fiber diet consumption. Inclusion of dietary fiber into the low fiber diet (LFD) increased the abundance of genera Lactobacillus and Anaerostipes, the microbes responsible for butyrate (major 'fuel source' of colonocytes) production. Mice fed LFD with ${\beta}-glucan$ showed significant increase in the length of small intestine compared to that of the LFD group without ${\beta}-glucan$. Further, dietary fiber consumption enhanced goblet cell density along with mucosal layer thickness. These results indicate promising effects of ${\beta}-glucan$ towards maintenance of healthy gut and gut microbiota.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.447-453
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• 2015

We determined the optimal culture conditions for obtaining the maximum number of intestinal bacteria from the olive flounder Paralichthys olivaceus, and studied bacterial diversity using both culture-dependent and culture-independent methods. Using six culture conditions, mean bacterial numbers were greater than $10^6$ per gram of gut mucus, regardless of the medium. However, the bacterial diversity, based on colony morphology, appeared much higher on Marine agar (MA) and Zobell 2216 agar than on other media. We found eight and 17 cultured bacterial phylotypes with 99% minimum similarity in gut mucus grown on MA and tryptic soy agar, respectively. Furthermore, we used genomic DNA extracted from gut mucus to generate 78 random clones, which were grouped into 25 phylotypes. Of these, six were affiliated with Firmicutes, Actinobacteria, and Verrucomicrobia, and were not found using our culture-dependent methods. Consequently, we believe that Marine agar and Zobell 2216 agar are optimal media for culturing diverse intestinal microbes; we also discovered several novel sequences not previously recognized as part of the gut microbiota of olive flounder.