• Journal of Periodontal and Implant Science
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• v.49 no.5
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• pp.270-286
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• 2019

Purpose: Despite the well-known anti-inflammatory effects of vitamin D in periodontal health, its mechanism has not been fully elucidated. In the present study, the effect of vitamin D on strengthening E-cadherin junctions (ECJs) was explored in human gingival keratinocytes (HGKs). ECJs are the major type of intercellular junction within the junctional epithelium, where loose intercellular junctions develop and microbial invasion primarily occurs. Methods: HOK-16B cells, an immortalized normal human gingival cell line, were used for the study. To mimic the inflammatory environment, cells were treated with tumor necrosis factor-alpha ($TNF-{\alpha}$). Matrix metalloproteinases (MMPs) in the culture medium were assessed by an MMP antibody microarray and gelatin zymography. The expression of various molecules was investigated using western blotting. The extent of ECJ development was evaluated by comparing the average relative extent of the ECJs around the periphery of each cell after immunocytochemical E-cadherin staining. Vitamin D receptor (VDR) expression was examined via immunohistochemical analysis. Results: $TNF-{\alpha}$ downregulated the development of the ECJs of the HGKs. Dissociation of the ECJs by $TNF-{\alpha}$ was accompanied by the upregulation of MMP-9 production and suppressed by a specific MMP-9 inhibitor, Bay 11-7082. Exogenous MMP-9 decreased the development of ECJs. Vitamin D reduced the production of MMP-9 and attenuated the breakdown of ECJs in the HGKs treated with $TNF-{\alpha}$. In addition, vitamin D downregulated $TNF-{\alpha}$-induced nuclear factor kappa B ($NF-{\kappa}B$) signaling in the HGKs. VDR was expressed in the gingival epithelium, including the junctional epithelium. Conclusions: These results suggest that vitamin D may avert $TNF-{\alpha}$-induced downregulation of the development of ECJs in HGKs by decreasing the production of MMP-9, which was upregulated by $TNF-{\alpha}$. Vitamin D may reinforce ECJs by downregulating $NF-{\kappa}B$ signaling, which is upregulated by $TNF-{\alpha}$. Strengthening the epithelial barrier may be a way for vitamin D to protect the periodontium from bacterial invasion.

• 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.

• Journal of Life Science
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• v.34 no.9
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• pp.647-655
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• 2024

The synthesis of cerium oxide nanoparticles (nanoceria, CeO₂) has received significant attention across scientific and technological disciplines in the last decade. This article explores an overview of the green synthesis method and the antibacterial activity of nanoceria. The utilization of biological materials, such as plants and microorganisms, in the synthesis of nanoceria, has gained attention as an ecofriendly approach. Plants are rich in phytochemicals, including alkaloids, flavonoids, phenols, proteins, and other nutritious components. Likewise, microorganisms generate bioactive metabolites, pigments, enzymes, proteins, acids, and antibiotics. The phytochemicals and metabolites are involved in the reduction of metal salt into nanoceria and provide stability to synthesized nanoparticles. Nanoceria synthesis using plants and microorganisms is facile and ecofriendly, and synthesized nanoceria are biocompatible. Many biomedical applications of nanoceria have been reported, including those that are anticancer, anti-inflammatory, larvicidal, enzyme inhibiting, antibiofilm, and antimicrobial. However, in this review, we focused on and described in detail the antibacterial potential of nanoceria. The antibacterial activity of nanoceria occurs due to excessive reactive oxygen species generation, the impairment of the cell membrane, and the inhibition of cellular mechanisms. Ultimately, this review's primary goal is to provide readers with a logical understanding of the significant achievements of nanoceria as a cutting-edge therapeutic agent for treating a range of microbial pathogens and combating other diseases.

• Journal of Life Science
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• v.31 no.6
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• pp.595-602
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• 2021

Human intestinal microbiota play an important role in the regulation of the host's metabolism. There is a close pathological and physiological interaction between dysbiosis of the intestinal microflora and obesity and metabolic syndrome. Akkermansia muciniphila, which was recently isolated from human feces, accounts for about 1-4% of the intestinal microbiota population. The use of A. muciniphila- derived external membrane protein Amuc_1100 and extracellular vesicles (EVs) could be a new strategy for the treatment of obesity. A. muciniphila is considered a next-generation probiotic (NGP) for the treatment of metabolic disorders, such as obesity. Faecalibacterium prausnitzii accounts for about 5% of the intestinal microbiota population in healthy adults and is an indicator of gut health. F. prausnitzii is a butyrate-producing bacterium, with anti-inflammatory effects, and is considered an NGP for the treatment of immune diseases and diabetes. Postbiotics are complex mixtures of metabolites contained in the cell supernatant secreted by probiotics. Parabiotics are microbial cells in which probiotics are inactivated. Paraprobiotics and postbiotics have many advantages over probiotics, such as clear chemical structures, safe dose parameters, and a long shelf life. Thus, they have the potential to replace probiotics. The most natural strategy to restore the imbalance of the intestinal ecosystem normally is to use NGPs among commensal bacteria in the gut. Therefore, it is necessary to develop new foods or drugs such as parabiotics and postbiotics using NGPs.

• Journal of Life Science
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• v.23 no.11
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• pp.1409-1414
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• 2013

Lymph node (LN) is the sites where mature lymphocytes become stimulated to respond to invading pathogens in the body. Lymphocytes screen the surfaces of pathogen-carrying antigen-presenting cells for cognate antigens, while moving along stromal structural back bone. Fibroblastic reticular cells (FRC) is stromal cell forming the 3 dimensional structure networks of the T cell rich zones in LN, and provide a guidance path for immigrating T lymphocytes. In these cooperative environments, the cell to cell bidirectional interactions between FRC and T cells in LN are therefore essential to the normal functioning of these tissues. Not only do FRCs physically construct LN architecture but they are essential for regulating T cell biology within these domains. FRC interact closely with T lymphocytes, is providing scaffolds, secreting soluble factors including cytokine in which FRCs influence T cell immune response. More recently, FRC have been found to induce peripheral T cell tolerance and regulate the extent to which newly activated T cells proliferate within LN. Thus, FRC-T cell crosstalk has important consequences for regulating immune cell function within LN. In addition, FRC have profound effects on innate immune response by secreting anti-microbial peptides and complement, etc in the inflammatory milieu. In summary, we propose a model in which FRC engage in a bidirectional touch to increase the T cell biological efficiency between FRC and T cells. This collaborative feedback loop may help to maintain tissue function during inflammation response.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.141-152
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• 2016

The demand to develop more safe and efficient methods for treating allergic patient is now continuously growing due to the increasing prevalence of allergic diseases. Probiotics are endogenous microbial flora that gives health benefits within hosts. Probiotics are now considered as one of solutions to treat allergic patients since recent evidence shows that some of probiotics have immunomodulatory function. Also, the treatment of probiotics to patients is relatively safer than other anti-inflammatory agents. In this review, we summarized on immunomodulatory function of some probiotics which show preventive or therapeutic effects on major allergic diseases such as atopic dermatitis, allergic rhinitis, asthma, or food allergy. Based on previous literature, the treatment of probiotics can alleviate the symptoms of allergic diseases via balancing $Th_1/Th_2$ response or increasing the number of regulatory T ($T_{reg}$) cells.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.350-357
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• 2013

Lichens are symbiotic organisms composed of fungi, algae, or cyanobacteria which are able to survive in extreme environmental conditions ranging from deserts to polar areas. Some lichen symbionts produce a wide range of secondary metabolites that have many biological activities such as antibacterial, antifungal, antiviral, antitumor, antioxidant and anti-inflammatory etc. Among the symbionts of lichens, of the bacterial communities of lichen symbionts little is known. In this study, we isolated 4 microbial species from the Arctic lichen Stereocaulon spp. and evaluated their antioxidant properties using 1,1-diphenyl-2-picryl-hydrazyl assay as well as 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) assay. Total phenolic contents and total flavonoid contents were also measured. A potent radical scavenging activity was detected in a number of the lichen extracts. Among the 4 species tested in this study, the ethyl acetate extract of Bosea vestrisii 36546(T) exhibited the strongest free radical scavenging activity, with an inhibition rate of 86.8% in DPPH and 75.2% in ABTS assays. Overall, these results suggest that lichen-bacteria could be a potential source of natural antioxidants.

• Journal of Dairy Science and Biotechnology
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• v.33 no.2
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• pp.111-118
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• 2015

Probiotic, prebiotic, and synbiotic substances as well as microorganisms were added to infant formula in an attempt to influence the intestinal microflora with an aim to stimulate the growth of lactic acid bacteria, especially bifidobacteria and lactobacilli. Over the last 10 years, new synbiotic infant formulas containing probiotics and prebiotics have been proposed in order to simulate the effect of breast-feeding on the intestinal microflora. Owing to their synergistic effect, the new synbiotics are expected to be more helpful than using probiotics and prebiotics individually. Maintenance of the viability of the probiotics during food processing and the passage through the gastrointestinal tract should be the most important consideration, since a sufficient number of bacteria ($10^8cfu/g$) should reach the intended location to have a positive effect on the host. Storage conditions and the processing technology used for the manufacture of products such as infant formula adversely affect the viability of the probiotics. When an appropriate and cost-effective microencapsulation methodology using the generally recognized as safe (GRAS) status and substances with high biological value are developed, the quality of infant formulas would improve. The effect of probiotics may be called a double-effect, where one is an immunomodulatory effect, induced by live probiotics that advantageously alter the gastrointestinal microflora, and the other comprises anti-inflammatory responses elicited by dead cells. At present, a new terminology is required to define the dead microorganisms or crude microbial fractions that positively affect health. The term "paraprobiotics" (or ghost probiotics) has been proposed to define dead microbial cells (not damaged or broken) or crude cell extracts (i.e., cell extracts with complex chemical composition) that are beneficial to humans and animals when a sufficient amount is orally or topically administered. The fecal microflora of bottle-fed infants is altered when the milk-based infant formula is supplemented with probiotics or prebiotics. Thus, by increasing the proportion of beneficial bacteria such as bifidobacteria and lactobacilli, prebiotics modify the fecal microbial composition and accordingly regulate the activity of the immune system. Therefore, considerable attention has been focused on the improvement of infant formula quality such that its beneficial effects are comparable to those of human milk, using prebiotics such as inulin and oligosaccharides and potential specific probiotics such as bifidobacteria, which selectively stimulate the proliferation of beneficial bacteria in the microflora and the indigenous intestinal metabolic activity of the microflora.