Ulcerative colitis is inflammatory conditions of the colon caused by interplay of genetic and environmental factors. Previous studies indicated that the gut microflora may be involved in the colonic inflammation.Bacteroides fragilis(BF) is a Gram-negative anaerobe belonging to the colonic symbiotic. We aimed to investigate the protective role ofBFin a colitis model induced in germ-free (GF) mice by dextran sulfate sodium (DSS). GF C57BL/6JNarl mice were colonized withBFfor 28 days before acute colitis was induced by DSS.BFcolonization significantly increased animal survival by 40%, with less reduction in colon length, and decreased infiltration of inflammatory cells (macrophages and neutrophils) in colon mucosa following challenge with DSS. In addition,BFcould enhance the mRNA expression of anti-inflammatory-related cytokine such as interleukin 10 (IL-10) with polymorphism cytokineIL-17and diminish that of proinflammatory-related tumor necrosis factorαwith inducible nitric oxide synthase in the ulcerated colon. Myeloperoxidase activity was also decreased inBF-DSS mice. Taking these together, theBFcolonization significantly ameliorated DSS-induced colitis by suppressing the activity of inflammatory-related molecules and inducing the production of anti-inflammatory cytokines.BFmay play an important role in maintaining intestinal immune system homeostasis and regulate inflammatory responses.

The domestic pig is an important source of human salmonellosis, and houseflies are potential mechanical vectors of foodborne Salmonella pathogens. In 2005, we recovered 144 Salmonella isolates from flies and swine stool samples from 11 farms in Taoyuan County and Hsin Chu County (northwestern Taiwan). A total of 71.5% of the isolates were resistant to at least three antibiotics. There were a total of 14 serotypes, and 8 of these serotypes were present in both flies and swine stool samples. Some multidrug-resistant Salmonella strains coming from different swine farms were found to have identical pulsed-field gel electrophoresis (PFGE). Among four common serotypes, we identified 18 PFGE patterns, 8 of which were present in flies and swine stools. The similarity in PFGE profiles between isolates from swine and flies in different farms indicate the potential of flies to serve as a vector for transmission.

The widespread use of phthalates as plasticizers has raised public health concerns regarding their adverse effects, including an association with cancer. Although animal investigations have suggested an association between phthalate exposure and hepatocellular carcinoma, the mechanisms are unknown. The hepatocellular carcinoma cell line Huh7 was treated with benzyl butyl phthalate (BBP), and then analyzed by total internal reflection fluorescence microscopy, confocal microscopy and double immunogold transmission electron microscopy. Following BBP treatment, mRNA levels were measured by RT-PCR, protein levels were measured using western blot, and vascular endothelial growth factor levels were measured by an enzyme-linked immunosorbent assay. Cell migration and invasion assays were evaluated by transwell, and angiogenesis were performed by a tube formation assay. Nude mice were used to investigate metastasis and angiogenesis in vivo. BBP affected hepatocellular carcinoma progression through the aryl hydrocarbon receptor (AhR) and that benzyl butyl phthalate (BBP) stimulated AhR at the cell surface, which then interacted with G proteins and triggered a downstream signaling cascade. BBP activated AhR through a nongenomic action involving G-protein signaling rather than the classical genomic AhR action. BBP treatment promoted cell migration and invasion in vitro and metastasis in vivo via the AhR/Gβ/PI3K/Akt/NF-κB pathway. In addition, BBP induced both in vitro and in vivo angiogenesis through the AhR/ERK/VEGF pathway. These findings suggest a novel nongenomic AhR mechanism involving G-protein signaling induced by phthalates, which contributes to tumor progression of hepatocellular carcinoma.