Open reading frames and gene annotations were based on the TIGR database [23]. The genes were classified in different flagellar

classes, as previously proposed [8]. Confirmatory analysis by qRT-PCR was performed for genes with *. Values for genes with ** were lost during the initial array data analysis and subsequently recovered using 3 independent replicates. For technical reasons, some array spots could not be analyzed in individual arrays. Two genes involved in the cell division process were affected in the HP0256 mutant. HP0331/minD, coding for a protein involved in the correct localisation of the cell division site [37], was 1.7 fold down-regulated in the HP0256 mutant compared to the GSK458 nmr wild-type (confirmed by qRT-PCR investigation). In E. coli, MinD (in synergy with MinC) inhibits the cell check details division protein FtsZ, that forms the FtsZ or Z ring at the septum [38, 39]. Interestingly, ftsZ was 1.9 fold up-regulated in the HP0256 mutant (Table 1). Adhesion and pro-inflammatory properties of an HP0256 mutant The microarray data indicated altered expression of a number of genes encoding proteins associated with the cell envelope in the HP0256 mutant. The genes encoding the well-characterized adhesins BabA and BabB which bind to fucosylated Lewis antigens on human gastric cells were up-regulated in the HP0256 mutant.

To investigate a potential role of HP0256 in pathogenesis and adhesion, we measured adhesion of HP0256 mutant cells to gastric epithelial cells, and also interleukin-8 (IL-8) secretion by gastric epithelial cells using an in vitro infection model. Adhesion of the HP0256 mutant to AGS cells was SB202190 significantly mafosfamide reduced to 45% of that of the wild-type (p < 0.05) (Figure 7). Supernatants from that assay were also used to quantify IL-8 production by AGS cells. CCUG17874 induced an average of 2434 pg/ml of IL-8 from AGS cells compared to 1944 pg/ml by the HP0256 mutant (Figure 7). This is a statistically significant decrease of 20% (p < 0.02). Figure 7 The HP0256 mutant has lower adhesion ability compared to the wild-type and significantly induces a weaker IL-8 secretion in AGS cells. Panel A shows that the HP0256 mutant adheres significantly

less to the AGS host cells compared to the wild-type. Panel B shows that the HP0256 mutant induces a lower IL-8 secretion of AGS cells compared to the wild-type cells. (*) indicates results with a p-value of less than 0.05. Discussion A focused bioinformatics analysis based on the functional domain of FliJ (N-terminal coiled-coil domain) suggested that HP0256 was a potential FliJ homologue in H. pylori. HP0256 encodes a hypothetical protein in H. pylori and shares common properties with FliJ, such as a similar size and a predicted N-terminal coiled coil. However, in comparison with the complete loss of motility reported in a Salmonella FliJ mutant [27], H. pylori HP0256 mutants retained some motility based on a motility plate assay.