From this gene set 39 genes were W83-specific as they were absent in each of the test strains. In this way the prtT protease gene and a fimbrillin gene (fimA) were found to be aberrant in all test strains, but not W83-specific as they were present in one or more test strains. The results for fimA support the findings that the gene is widely distributed, but variable at the probe locus among P. gingivalis strains. Many of the genes found in this analysis are located within the highly variable regions described in earlier publications using whole-genome analysis. The existence of those regions were supported by data comparing the genome sequences

of P. gingivalis strains W83 and ATCC33277 [28]. Also in this study we found these regions

back in the analysis as described above Genes Selleck 5-Fluoracil only aberrant in FDC381 FDC381 is the only strain included in this study that does not produce CPS. It is also the least virulent strain in mouse studies. Here, an Bortezomib analysis was performed to find genes that are specifically aberrant in FDC381 and not in all the other test strains (Table 7). Alongside many genes encoding hypothetical proteins several genes of special interest were found. The genes PG1711 encoding an alpha-1,2-mannosidase family protein, and PG1972 encoding the hemagglutinin hagB, all thought to be involved in virulence either by a role in evasion of the immune system or by a role in adhesion to host cells [29, 59]. Table 7 Genes only aberrant in strain FDC381 GeneID Annotated function PG0183 lipoprotein, heptaminol putative PG0204 hypothetical protein PG0300 TPR domain protein PG0492 hypothetical protein PG1119 flavodoxin, putative PG1199 hypothetical protein PG1200 hypothetical protein PG1373 hypothetical protein PG1466 hypothetical protein PG1467 methlytransferase, UbiE-COQ5 family PG1473 conjugative transposon protein TraQ PG1685 hypothetical protein PG1711 alpha-1,2-mannosidase family protein PG1777 conserved

hypothetical protein PG1786 hypothetical protein PG1814 DNA primase PG1969 hypothetical protein PG1970 hypothetical protein PG1972 hemagglutinin protein HagB PG1977 hypothetical protein PG1978 hypothetical protein Although these data do not directly show any CPS biosynthesis specific genes aberrant only in the non-encapsulated FDC381 it does give hints towards other virulence associated traits that are missing in FDC381. High versus lower virulence strains When comparing the core gene set of only the highly virulent strains W83, HG1025, ATCC49417 and HG1690 with the genes aberrant in each of the less virulent strains HG184, HG1691, 34-4 and FDC381 an interesting result was seen. There is only a single gene, hmuS, that is present in all highly virulent strains but aberrant in each of the less virulent strains. HmuS is part of the hmuYRSTUV haemin uptake system [60].