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Aims:  The aims of the present study are to characterize the intestinal microbial community displaying a high‐adhesive capability in fish, and to evaluate the relationship between mucosal adhesion of intestinal bacteria and fish health and disease. Methods and Results:  A total of 707 aerobic bacteria isolated from carp intestine that were maintained under either feeding (feeding group) or no‐feeding (no‐feeding group) conditions and were performed adhesive assay. Isolates were divided into three categories on the basis of adhesive capability: high‐, medium‐, and low‐ adhesive capabilities. The average proportions of isolates with high‐adhesive capability in the feeding and no‐feeding groups were 30% and 32%, respectively. A phylogenetic analysis using a partial 16S rRNA gene demonstrated that most isolates with high‐adhesive capability in both groups were classified as belonging to an Aeromonas group, and populations of isolates within high‐ and low‐adhesive categories were markedly different. Conclusions:  Intestinal bacteria with a high‐adhesive capability in relation to intestinal mucous always colonize on the surface of intestinal mucosa and grow in the intestinal tract of feeding carp. The adhesive capability of intestinal bacteria is essential for colonization and growth in the intestinal tract of fish. Significance and Impact of the Study:  Our results indicate that members of the Aeromonas group with adhesive capability always colonize on the surface of intestinal mucosa.

Elevated concentrations of interleukin (IL)-6 and soluble IL-6 receptor (sIL-6Ralpha) in synovial fluid have been implicated in joint cartilage destruction. We examined the effect of IL-6 and sIL-6Ralpha on cell growth, alkaline phosphatase (ALPase) activity, and the expression of Sox-9, type II collagen, aggrecan core, link protein, BMP-7, and BMP receptors in human chondrocytes. Cell proliferation increased slightly in the presence of both IL-6 and sIL-6Ralpha, whereas ALPase activity decreased markedly. The expression of Sox-9 and aggrecan core did not change in the presence or absence of IL-6 and sIL-6Ralpha, whereas the expression of type II collagen, link protein, BMP-7, and BMP receptors increased in the presence of both IL-6 and sIL-6Ralpha. These results suggest that IL-6 and sIL-6Ralpha suppress the differentiation of chondrocytes and induce the repair of arthrodial cartilage through an increase in the expression of cartilage matrix proteins, BMP-7, and BMP receptors in the cells.

Aims:  In the present study, we focused on one of the Aeromonas veronii isolates that exhibited marked adhesion onto carp intestine and studied its membrane‐associated proteins for their possible involvement in mucosal adhesion. Methods and Results:  We isolated a strain of Aer. veronii (CWP11) that exhibited a high degree of temperature‐dependent adhesion activity onto carp intestinal tract and studied its adhesion factor. A proteomic analysis of the membrane‐associated fraction showed the presence of multiple proteins that were specifically expressed in CWP11 cells cultured at 25°C. Of these, a 30 kDa protein was identified to be OmpA by a mass fingerprint analysis. Cloning and nucleotide sequencing of the ompA region of CWP11 revealed the presence of two tandem ompA homologues (ompAI‐ompAII). Escherichia coli that expressed either OmpAI or OmpAII exhibited marked adhesion onto carp intestinal surface. Disruption of ompAI by a homologous recombination technique resulted in marked reduction of the adhesion activity in CWP11. Conclusion:  The OmpA homologue plays an important role in the adhesion of the Aer. veronii strain onto the surface of intestinal tract. Significance and Impact of the Study:  We successfully identified an OmpA homologue to be an adhesion factor of Aer. veronii, an optimistic pathogen that habituates in carp intestinal tract.

Prostaglandin (PG) E(2), which exerts its actions via the PG receptors EP1-4, is produced from arachidonic acid by cyclooxygenase (COX)-1 and COX-2. The aim of this study was to investigate the mechanisms by which interleukin (IL)-1beta induces the expression of PG receptors in cultured human chondrocytes and to explore the role of PGE(2) in this process. The cells were cultured with 0, 10, or 100 U/mL IL-1beta with or without 1 muM celecoxib, a specific inhibitor of COX-2, for up to 28 days. Expression of the genes encoding COX-1, COX-2, and EP1-4 was quantified using real-time PCR, and expression of the corresponding proteins was examined using immunohistochemical staining. PGE(2) production was determined using ELISA. IL-1beta treatment caused a marked dose- and time-dependent increase in the levels of PGE(2), COX-2, and EP4 as compared with the untreated control. It did not affect the expression of COX-1, and it decreased the expression of EP1 and EP2. EP3 expression was not detected in either the absence or the presence of IL-1beta. When celecoxib was also present, IL-1beta failed to stimulate PGE(2) production and EP4 expression, but its stimulatory effect on COX-2 expression and its inhibitory effect on EP1 and EP2 expression were unchanged. IL-1beta increases the production of PGE(2), COX-2, and the PG receptor EP4 in cultured human chondrocytes. The increase in EP4 expression appears to be a result of the increased PGE(2) production.