Results Whereas none of the 103 tested Viruses and none of the 101 tested Archaea genomes exhibited the 3-gene set (Table 1, Additional file 1), some representatives encode one or two genes of this 3-gene set. Indeed, the Pseudomonas phage JG024 and Burkholderia ambifaria phage Bcep F1 genomes encode one GH23 gene each. For

Archaea, the Methanosaetaconcilii GP-6 genome selleck kinase inhibitor contained one GH73, and the Methanothermobacter marburgensis str. Marburg, Methanobacterium sp. AL-21, Methanothermus fervidus DSM 2088 and Methanopyrus kandleri AV19 genomes encode one GT28 gene. Among 42 tested Eukaryota, only the Micromonas sp. genome encodes GT28, GT51 and GH103 (Table 1, Figure 1, Additional file 1). A total of 4 other photosynthetic eukaryotic genomes do not contain the complete 3-gene set but do encode a portion of these genes: the Selleckchem LCL161 Ostreococcus lucimarinus CCE9901 and Oryza sativa

japonica group nuclear genomes encode one and four GT28 genes, respectively; and the Arabidopsis thaliana nuclear and chloroplastic genomes encode a total of four GT28 genes. The Paulinella chromatophora chromatophore genome encodes one GT28 and one GT51 gene. Three non-photosynthetic Eukaryota genomes encode Selleck Defactinib one GH23 gene, i.e. Cryptococcus bacillisporus WM276, Cryptococcus neoformans var. neoformans and Homo sapiens. By analyzing the presence of at least one gene of the 3-gene set in 42 Eukaryota genomes, we found that these genes were significantly more present in the photosynthetic Eukaryota genomes (5/7, 71.4%) than in the non-photosynthetic Eukaryota genomes (3/35, 8.5%) (P-value=0.0001). Comparing

the presence of each gene family between Bacteria and the other domains of life yielded a significant association between Bacteria and the presence of GH23, GH73, GH102, GH103, GT28 (P-value <10-7) and GH104 (P-value <2.10-5). The 3-gene set was found in 1,260/1,398 (90.1%) bacteria, whereas 138 (9.9%) bacteria appeared to lack at least one of these three genes (Table 1; Additional file 2 and Additional file 3). A review of the literature indicated that all Bacteria possessing the 3-gene set have been previously demonstrated to have PG, resulting Sulfite dehydrogenase in a 100% positive predictive value of the 3-gene set for the presence of PG in an organism. For 30/138 (21.7%) organisms lacking the 3-gene set, PG information was lacking in the literature, whereas a literature review confirmed the absence of PG in 84/138 (60.9%) and the presence of PG in 24/138 (17.4%) organisms (Additional file 3). These data yielded a 77.8% negative predictive value of the 3-gene set for the presence of PG (Table 1). Table 1 Distribution of peptidoglycan metabolism genes among all of the domains of life and among 21 bacteria phyla   Bacteria phyla GT28 GT51 GH23 GH25 GH73 GH102 GH103 GH104 Complete set Archae (n=101)   4 (3.9%) 0 0 1 (0.