Association between and irritable bowel syndrome with diarrhoea.

Objective: The incidence of IBS increases following enteric infections, suggesting a causative role for microbial imbalance. However, analyses of faecal microbiota have not demonstrated consistent alterations. Here, we used metaproteomics to investigate potential associations between mucus-resident microbiota and IBS symptoms.

Normalization of Host Intestinal Mucus Layers Requires Long-Term Microbial Colonization.

The intestinal mucus layer provides a barrier limiting bacterial contact with the underlying epithelium. Mucus structure is shaped by intestinal location and the microbiota. To understand how commensals modulate gut mucus, we examined mucus properties under germ-free (GF) conditions and during microbial colonization.

The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system.

The gastrointestinal tract is covered by mucus that has different properties in the stomach, small intestine, and colon. The large highly glycosylated gel-forming mucins MUC2 and MUC5AC are the major components of the mucus in the intestine and stomach, respectively. In the small intestine, mucus limits the number of bacteria that can reach the epithelium and the Peyer's patches.

Toxic activity of the CdtB component of Haemophilus ducreyi cytolethal distending toxin expressed from an adenovirus 5 vector.

The Haemophilus ducreyi cytolethal distending toxin (HdCDT) catalytic subunit CdtB has DNase-like activity and mediates DNA damage after its delivery into target cells. We constructed a replication-deficient adenovirus type 5 (Ad5) vector expressing CdtB and investigated the toxic properties of this vector on HeLa cells. Ad5CdtB caused loss of cell viability, morphologic changes, and cell cycle arrest, findings similar to HdCDT intoxication.

Formaldehyde treatment increases the immunogenicity and decreases the toxicity of Haemophilus ducreyi cytolethal distending toxin.

Haemophilus ducreyi cytolethal distending toxin (HdCDT) is a tripartite AB toxin, which causes DNA damage in affected cells. We investigated the effects of formaldehyde on the chemical, biological, and immunological properties of the HdCDT complex, which was purified by immobilizing the glutathione S-transferase (GST)-CdtB fusion protein, followed by binding of the CdtA and CdtC recombinant proteins. The HdCDT was treated with increasing concentrations of formaldehyde in the presence of lysine.

The cytolethal distending toxin of Haemophilus ducreyi aggravates dermal lesions in a rabbit model of chancroid.

Haemophilus ducreyi, the etiologic agent of the sexually transmitted disease chancroid, produces a cytolethal distending toxin (HdCDT) that inhibits cultured cell proliferation, leading to cell death. A rabbit model of dermal infection was used to investigate the roles of H. ducreyi bacteria and HdCDT in the development, clinical appearance, and persistence of infection.

Induction of apoptosis/necrosis in various human cell lineages by Haemophilus ducreyi cytolethal distending toxin.

We investigated the impact of highly purified Haemophilus ducreyi cytolethal distending toxin (HdCDT) on the apoptosis and necrosis of various human cells; including myeloid cells, epithelial cells, keratinocytes, and primary fibroblasts. The levels of apoptosis and necrosis induced in these cells were compared to those induced by HdCDT in human T cells and in the Jurkat T cell line. Levels of caspase-3 activity were measured, and membrane changes like phosphatidylserine (PS) translocation was evaluated after double-staining with the fluorescein isothiocyanate (FITC)-labeled annexin V and propidium iodide (PI) using flow cytometry.

Toxicity and immunogenicity of purified Haemophilus ducreyi cytolethal distending toxin in a rabbit model.

The cytolethal distending toxin of Haemophilus ducreyi (HdCDT) is a three-component toxin that induces the arrest of the mammalian cell cycle in the G2 phase. All of the individual gene products, CdtA, CdtB and CdtC, are required for toxic activity on cultured mammalian cells. The CdtB component alone exerts nuclease activity.