Gelatin but not type I collagen promotes bacteria phagocytosis in PMA-treated U937 human lymphoma cells.

Purpose: Besides comprising scaffolding, extracellular matrix components modulate many biological processes including inflammation and cell differentiation. We previously found precoating cell plates with extracellular matrix collagen I, or its denatured product gelatin, causes aggregation of macrophage-like human lymphoma U937 cells, which are induced to differentiation by phorbol myristate treatment. In the present study, we investigated the influence of gelatin or collagen I precoating on the bacteria phagocytosis in PMA-stimulated U937 cells.

Post-translational suppression of the high affinity IgE receptor expression on mast cells by an intestinal bacterium.

Mast cells, which express the high-affinity IgE receptor (FcεRI) on their surface, play a crucial role in inducing allergic inflammation. Since mast cells are activated by crosslinking of FcεRI with IgE and allergens, the cell surface expression level of FcεRI is an important factor in determining the sensitivity to allergens. Recently, the involvement of gut microbiota in the prevalence and regulation of allergy has attracted attention but the precise underlying mechanisms are not fully understood.

A Soluble Fiber Diet Increases Bacteroides fragilis Group Abundance and Immunoglobulin A Production in the Gut.

Immunoglobulin A (IgA) is essential for defense of the intestinal mucosa against harmful pathogens. Previous studies have shown that , the major phylum of gut microbiota together with , impact IgA production. However, the relative abundances of species of responsible for IgA production were not well understood.

Resistin-like molecule beta, a colonic epithelial protein, exhibits antimicrobial activity against Staphylococcus aureus including methicillin-resistant strains.

Purpose: Resistin-like molecule beta (RELMβ) is a small cysteine-rich protein secreted by colonic epithelial cells. RELMβ mRNA and protein expressions are dramatically induced by bacterial exposure in germ-free mice. We hypothesized that RELMβ has antimicrobial activity.

Metformin protects from bleomycin-induced bactericide via enhanced generation of hydrogen peroxide.

Bleomycin is a glycopeptide antibiotic that is widely employed in the therapy of a range of lymphomas and germ cell tumours. But the therapeutic efficacy of bleomycin is limited by development of lung fibrosis. The cytotoxicity of bleomycin is mostly ascribed to mitochondrial DNA (mtDNA) damage, while a protective effect of metformin against bleomycin-induced lung fibrosis results from the inhibition of mitochondrial complex I.

Prostaglandin E2 attenuates synergistic bactericidal effects between COX inhibitors and antibiotics on Staphylococcus aureus.

PGE2 is found to attenuate the bactericidal effects of kanamycin or ampicillin in Staphylococcus aureus, as well as the methicillin-resistant S. aureus (MRSA). Co-treatment with cyclooxygenase (COX) inhibitors (celecoxib, aspirin or naproxen) synergistically enhances kanamycin or ampicillin-induced cell death of S.

Concentration-dependent dual effects of silibinin on kanamycin-induced cells death in Staphylococcus aureus.

Silibinin has dual effects on bacteria, depending on the concentrations or living contexts. The mechanism of either action has not yet been elucidated. Present study suggests that silibinin has yinyang impacts on the growth of Staphylococcus aureus depending on doses.

Salicylate induces reactive oxygen species and reduces ultraviolet C susceptibility in Staphylococcus aureus.

This study demonstrates that growth of Staphylococcus aureus in the presence of salicylate reduces ultraviolet C (UVC)-induced cell death and increases the generation of reactive oxygen species (ROS). In addition, compounds that scavenge ROS (N-acetylcysteine, glutathione, catalase and superoxide dismutase) reverse the increased UVC survival induced by growth in the presence of salicylate, while ROS donors (tert-butylhydroperoxide, H2O2 and NaClO) enhance survival of salicylate challenged cultures. Collectively, these findings suggest that ROS production induced by growth in the presence of salicylate protects S.

Effects of Prenatal Consumption of Caprine Milk Oligosaccharides on Mice Mono-associated with (AGR2166).

Background: Prenatal consumption of oligosaccharides are associated with changes in the maternal gastrointestinal tract (GIT) microbiota with health consequences for the offspring. It has previously been demonstrated that caprine milk oligosaccharides (CMO) stimulate the growth and fermentation rate of AGR2166.

Objective: The objective of this study was to examine the effects of AGR2166 and prenatal consumption of CMO, alone or in combination, on the dam's large intestine, foetal development and ability of to translocate from the gastrointestinal lumen to organs and foetal membranes.

Gut microbiota as a source of a surrogate antigen that triggers autoimmunity in an immune privileged site.

Recent discoveries on the role of commensal microbiota have significantly changed our understanding of human physiology. The host-microbiota interplay is now an important aspect to take into account to understand immune responses and immunological diseases. Autoimmune uveitis is a sight-threatening disease that arises without a known infectious etiology.

C/EBPα controls mast cell function.

CCAAT/enhancer binding protein alpha (C/EBPα) is a transcription factor that influences immune cell fate and differentiation. However, the effect of C/EBPα on mast cells is not fully understood. In this study, we showed that C/EBPα suppressed granule formation in mast cells and increased macrophage inflammatory protein (MIP)-2 production from mast cells upon bacterial stimulation.

Intestinal colonization by a Lachnospiraceae bacterium contributes to the development of diabetes in obese mice.

The aim of the present study was to identify bacteria that may contribute to the onset of metabolic dysfunctions. We isolated and identified a candidate bacterium belonging to Lachnospiraceae (strain AJ110941) in the feces of hyperglycemic obese mice. The colonization of germ-free ob/ob mice by AJ110941 induced significant increases in fasting blood glucose levels as well as liver and mesenteric adipose tissue weights, and decreases in plasma insulin levels and HOMA-β values.

Commensal bacteria directly suppress in vitro degranulation of mast cells in a MyD88-independent manner.

The intestine harbors a substantial number of commensal bacteria that provide considerable benefits to the host. Epidemiologic studies have identified associations between alterations in the composition of the intestinal microbiota and the development of allergic disease. However, the cellular and molecular mechanisms underlying these effects remain to be determined.

Screening for intestinal microflora influencing superoxide dismutase activity in mouse cecal mucosa.

We have suggested that intestinal microflora reduces the activity of the antioxidant enzyme superoxide dismutase (SOD) in the mouse cecal mucosa. In this study, gnotobiotic mice were used to examine the species of intestinal microflora influencing SOD activity in the cecal mucosa. The total SOD activity in the cecal mucosa of each germ-free (GF), gnotobiotic mouse with Escherichia coli, Lactobacillus and Bacteroides was significantly higher than that in the cecal mucosa of gnotobiotic mice with chloroform-treated feces (CHF), conventionalized (CVz) mice and conventional (CV) mice (P<0.

IgA production in the large intestine is modulated by a different mechanism than in the small intestine: Bacteroides acidifaciens promotes IgA production in the large intestine by inducing germinal center formation and increasing the number of IgA+ B cells.

It has been demonstrated that intestinal commensal bacteria induce immunoglobulin (Ig) A production by promoting the development of gut-associated lymphoid tissues in the small intestine. However, the precise mechanism whereby these bacteria modulate IgA production in the large intestine, which harbors the majority of intestinal commensals, is poorly understood. In addition, it is not known which commensal bacteria induce IgA production in the small intestine and which induce production in the large intestine.

The induction of Treg cells by gut-indigenous Clostridium.

Foxp3+ CD4+ cells are prominent immune regulatory T (Treg) cells that are most abundant in the intestine. Recent studies have suggested that intestinal Treg cells consist of thymically and extrathymically developed cells that have unique characteristics. A fraction of intestinal Treg cells express T cell receptors that recognize antigens that are derived from the gut microbiota.

Design and application of group-specific oligonucleotide probes for detecting and monitoring mouse clostridia.

Clostridia dominate the rodent intestinal bacterial community and play an important role in physiological functions of the host. However, their ecology and diversity are still unclear. In our previous report, we showed that phylogenetically novel groups of clostridia inhabit the mouse intestine and contribute to the normalization of germfree mice.

The lifestyle of the segmented filamentous bacterium: a non-culturable gut-associated immunostimulating microbe inferred by whole-genome sequencing.

Numerous microbes inhabit the mammalian intestinal track and strongly impact host physiology; however, our understanding of this ecosystem remains limited owing to the high complexity of the microbial community and the presence of numerous non-culturable microbes. Segmented filamentous bacteria (SFBs), which are clostridia-related Gram-positive bacteria, are among such non-culturable populations and are well known for their unique morphology and tight attachment to intestinal epithelial cells. Recent studies have revealed that SFBs play crucial roles in the post-natal maturation of gut immune function, especially the induction of Th17 lymphocytes.

Bifidobacteria can protect from enteropathogenic infection through production of acetate.

The human gut is colonized with a wide variety of microorganisms, including species, such as those belonging to the bacterial genus Bifidobacterium, that have beneficial effects on human physiology and pathology. Among the most distinctive benefits of bifidobacteria are modulation of host defence responses and protection against infectious diseases. Nevertheless, the molecular mechanisms underlying these effects have barely been elucidated.

Induction of colonic regulatory T cells by indigenous Clostridium species.

CD4(+) T regulatory cells (T(regs)), which express the Foxp3 transcription factor, play a critical role in the maintenance of immune homeostasis. Here, we show that in mice, T(regs) were most abundant in the colonic mucosa. The spore-forming component of indigenous intestinal microbiota, particularly clusters IV and XIVa of the genus Clostridium, promoted T(reg) cell accumulation.

Metabolism of Isoflavones Found in the Pueraria thomsonii Flower by Human Intestinal Microbiota.

Isoflavones contained in the root and flower of Kudzu (Pueraria lobata and related species) are suggested to be the critical component for its effects. Although metabolism of soy isoflavones has been well studied, the composition of isoflavones found in Kudzu is completely different from that of soy isoflavones. In the present study, we investigated whether isoflavones found in the flower of Pueraria thomsonii, a species of Kudzu, were metabolized by human fecal microbiota and murine small intestinal enzymes.

Inhibitory effect of yogurt on aberrant crypt foci formation in the rat colon and colorectal tumorigenesis in RasH2 mice.

The inhibitory effects of yogurt consisting of milk fermented by Lactobacillus delbrueckii subsp. bulgaricus strain 2038 and Streptococcus salivarius subsp. thermophilus strain 1131 on formation of colonic aberrant crypt foci (ACF) in rats and also on development of colorectal tumors in transgenic mice harboring human prototype c-Ha-ras genes (rasH2 mice) were examined.

Intestinal commensal bacteria promote T cell hyporesponsiveness and down-regulate the serum antibody responses induced by dietary antigen.

Colonization of the gut by commensal bacteria modulates the induction of oral tolerance and allergy. However, how these intestinal bacteria modulate antigen-specific T cell responses induced by oral antigens remains unclear. In order to investigate this, we used germ-free (GF) ovalbumin (OVA)-specific T cell receptor transgenic (OVA23-3) mice.

Fructobacillus tropaeoli sp. nov., a fructophilic lactic acid bacterium isolated from a flower.

A fructophilic lactic acid bacterium, designated strain F214-1(T), was isolated from a flower of Tropaeolum majus in South Africa. Based on phylogenetic analysis of 16S rRNA gene sequences, the strain formed a subcluster with Fructobacillus ficulneus and Fructobacillus pseudoficulneus and, based on recA gene sequences, the strain formed a subcluster with F. ficulneus.

Naive CD4+ T lymphocytes circulate through lymphoid organs to interact with endogenous antigens and upregulate their function.

Naive T lymphocytes recirculate through the lymph-vascular system and enter and exit lymphoid organs. Using mice expressing the photoconvertible fluorescence protein Kaede, we demonstrated that naive T cells seek to interact with endogenous Ags after migrating to the lymphoid organs. The interaction with endogenous Ags transiently induces CD69 expression on T cells, which prolongs retention in the lymphoid organs.