• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1191-1197
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• 2007

The detection and kinetics of mucosal pathogenic bacteria binding on polysaccharide ligands were studied using a surface plasmon resonance biosensor. The kinetic model applied curve-fitting to the experimental surface plasmon resonance sensorgrams to evaluate the binding interactions. The kinetic parameters for the mucosal pathogenic bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens, Serratia marcescens) with the alginate ligand were determined from a kinetic model. In addition, the binding interactions of the mucosal pathogenic bacteria with polysaccharide binding pairs (Pseudomonas aeruginosa/alginate, Streptococcus pneumoniae/pneumococcal polysaccharide, Staphylococcus aureus/pectin) were also compared with their kinetic parameters. The rate constants of association for Pseudomonas aeruginosa with the alginate ligand were higher than those for Pseudomonas fluorescens. Serratia marcescens had no detectable interaction with the alginate ligand. The adhesion affinity of Pseudomonas aeruginosa with alginate was higher than that for the other binding pairs. The binding affinities of the pathogenic bacteria with their own polysaccharide were higher than that of Staphylococcus aureus with pectin. Measuring the contact angle was found to be a feasible method for detecting binding interactions between analytes and ligands.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.287-295
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• 2020

The differences between luminal microbiota (LM) and mucosal microbiota (MAM) were little known, especially in duodenum. In this study, LM and MAM in colon and duodenum of mice were investigated through 16S rRNA high-throughput sequencing. The lowest bacterial diversity and evenness were observed in duodenal LM (D_LM), followed by duodenal MAM (D_MAM). Meanwhile, the bacterial diversity and evenness were obviously increased in D_MAM than these in D_LM, while no significant difference was observed between colonic MAM (C_MAM) and colonic LM (C_LM). PCoA analysis also showed that bacterial communities of LM and MAM in duodenum were completely separated, while these in colon overlapped partly. The ratio of Firmicutes to Bacteroidetes (F/B) in D_MAM was significantly higher than that in D_LM. Lactobacillus was largely enriched and was the characteristic bacteria in D_LM. The characteristic bacteria in D_MAM were Turicibacter, Parasutterella, Marvinbryantia and Bifidobacterium, while in C_LM they were Ruminiclostridium_6, Ruminiclostridium_9, Ruminococcaceae_UCG_007 and Lachnospiraceae_UCG_010, and in C_MAM they were Lachnospiraceae_NK4A136, Mucispirillum, Alistipes, Ruminiclostridium and Odoribacter. The networks showed that more interactions existed in colonic microbiota (24 nodes and 74 edges) than in duodenal microbiota (17 nodes and 29 edges). The 16S rDNA function prediction results indicated that bigger differences of function exist between LM and MAM in duodenum than these in colon. In conclusion, microbiota from intestinal luminal content and mucosa were different both in colon and in duodenum, and bacteria in colon interacted with each other much more closely than those in duodenum.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.276-286
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• 2020

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. This study was conducted for the isolation of potential lactic acid bacteria (LAB) with probiotic properties from goat milk and yogurt. Several tests were conducted in vitro using the standard procedures for evaluating the inhibitory spectra of LAB against pathogenic bacteria; tolerance to NaCl, bile salt, and phenol; hemolytic, milk coagulation, and bile salt hydrolase activities; gastrointestinal transit tolerance; adhesion properties; and antibiotic susceptibility. Among 40 LAB strains screened according to culture characteristics, five isolates exhibited antagonistic properties. Three were identified as Pediococcus acidilactici, and two were identified as Enterococcus faecium, exploiting 16S rRNA gene sequencing. All the isolates succeeded in the gastrointestinal transit tolerance assay and successively colonized mucosal epithelial cells. Based on the results of these in vitro assays, both P. acidilactici and E. faecium can be considered as potential probiotic candidates.

• Journal of Dairy Science and Biotechnology
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• v.28 no.2
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• pp.25-30
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• 2010

For centuries, probiotics have been known to promote health and prevent diseases. In recent times, modulation of diseases related to the immune function by probiotics has been recognized as very important to the health of the host's gut. Inflammatory bowel diseases (IBDs) are the most frequently studied diseases in which probiotic administration has been tested as a potential therapy. Various in vitro and in vivo studies have been performed. The studies discussed in this review suggest several mechanisms: probiotics could modulate the gut microflora by competing with disease-causing pathogenic bacteria and could directly regulate the mucosal immune system, which activates the innate and adaptive immune systems. In addition, human clinical trials have shown alleviation of disease symptoms of ulcerative colitis (UC), Crohn's disease, etc. This study aimed to understand the molecular mechanisms underlying immune modulation by probiotics and review studies on the functional aspect of IBD alleviation by probiotics. With more scientific studies confirming the effect of probiotics, this therapy holds promise for use in alternative medicine and/or pharmaceutical preparations, given the long history of safe consumption of probiotics.

• International Journal of Oral Biology
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• v.40 no.3
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• pp.135-141
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• 2015

Biofilms of oral microbes can cause various diseases in the oral cavity, such as dental caries, periodontitis and mucosal disease. Electrolyzed water generated by an electric current passed via water using a metal electrode has an antimicrobial effect on pathogenic bacteria which cause food poisoning. This study investigated the antimicrobial activity of electrolyzed waters using various metal electrodes on the floatage and biofilms of oral microbes. The electrolyzed water was generated by passing electric current using copper, silver and platinum electrodes. The electrolyzed water has a neutral pH. Streptococcus mutans, Porphyromonas gingivalis and Tannerella forsythia were cultured, and were used to form a biofilm using specific media. The floatage and biofilm of the microbes were then treated with the electrolyzed water. The electrolyzed water using platinum electrode (EWP) exhibited strong antimicrobial activity against the floatage and biofilm of the oral microbes. However, the electrolyzed water using copper and silver electrodes had no effect. The EWP disrupted the biofilm of oral microbes, except the S. mutans biofilm. Comparing the different electrolyzed waters that we created the platinum electrode generated water may be an ideal candidate for prevention of dental caries and periodontitis.

• Animal Bioscience
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• v.35 no.10
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• pp.1461-1478
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• 2022

The maintenance of poultry gut health is complex depending on the intricate balance among diet, the commensal microbiota, and the mucosa, including the gut epithelium and the superimposing mucus layer. Changes in microflora composition and abundance can confer beneficial or detrimental effects on fowl. Antibiotics have devastating impacts on altering the landscape of gut microbiota, which further leads to antibiotic resistance or spread the pathogenic populations. By eliciting the landscape of gut microbiota, strategies should be made to break down the regulatory signals of pathogenic bacteria. The optional strategy of conferring dietary fibers (DFs) can be used to counterbalance the gut microbiota. DFs are the non-starch carbohydrates indigestible by host endogenous enzymes but can be fermented by symbiotic microbiota to produce short-chain fatty acids (SCFAs). This is one of the primary modes through which the gut microbiota interacts and communicate with the host. The majority of SCFAs are produced in the large intestine (particularly in the caecum), where they are taken up by the enterocytes or transported through portal vein circulation into the bloodstream. Recent shreds of evidence have elucidated that SCFAs affect the gut and modulate the tissues and organs either by activating G-protein-coupled receptors or affecting epigenetic modifications in the genome through inducing histone acetylase activities and inhibiting histone deacetylases. Thus, in this way, SCFAs vastly influence poultry health by promoting energy regulation, mucosal integrity, immune homeostasis, and immune maturation. In this review article, we will focus on DFs, which directly interact with gut microbes and lead to the production of SCFAs. Further, we will discuss the current molecular mechanisms of how SCFAs are generated, transported, and modulated the pro-and anti-inflammatory immune responses against pathogens and host physiology and gut health.