Table 2
Distribution of Ni/Co transporters in bacteria
| Phylum | Total organisms | CbiMNQO /NikMNQO /NikKMLQO | NikABCDE | NiCoT | UreH | HupE/UreJ | Other predicted Co transporters** | ||||||||||
| N* | C | U | N | C | U | N | C | U | N | C | U | N | C | U | |||
| Firmicutes/Lactobacillales | 25 | 1 | 2 | 2 | 2 | - | - | - | - | 3 | - | - | - | - | - | - | - |
| Firmicutes/Mollicutes | 17 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Firmicutes/Bacillales | 25 | - | 6 | - | 6 | - | - | 1 | - | 2 | 2 | - | 2 | - | - | - | - |
| Firmicutes/Clostridia | 38 | 8 | 20 | 15 | 3 | 2 | - | - | - | - | - | - | - | - | - | - | - |
| Chlamydiae | 7 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Bacteroidetes | 30 | - | 1 | - | - | - | - | - | - | - | 1 | - | 1 | - | - | - | 6 |
| Chlorobi | 9 | 7 | 2 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Actinobacteria | 40 | - | 2 | 13 | - | - | - | 2 | 1 | 11 | - | - | 1 | - | - | - | 17 |
| Spirochaetes | 8 | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
| Planctomycetes | 3 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Cyanobacteria | 16 | 7 | 5 | 5 | - | - | - | - | 1 | - | 1 | - | - | - | 10 | 1 | - |
| Chloroflexi | 7 | - | 3 | 3 | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Deinococcus-Thermus | 3 | - | - | - | - | - | - | - | 2 | - | - | - | - | 1 | - | - | - |
| Thermotogae | 6 | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Aquificae | 2 | - | - | - | - | - | - | 1 | - | - | - | - | - | 1 | - | - | - |
| Fusobacteria | 1 | - | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | 1 |
| Lentisphaerae | 2 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
| Verrucomicrobia | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Candidate division TM7 | 3 | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Acidobacteria | 2 | 1 | - | - | - | - | - | - | - | - | - | - | 2 | - | - | - | - |
| Deltaproteobacteria | 23 | 12 | 7 | 5 | - | - | - | - | - | - | - | - | 3 | - | - | - | 6 |
| Epsilonproteobacteria | 17 | 4 | - | 3 | 3 | - | - | 2 | - | - | 2 | - | - | - | - | - | - |
| Alphaproteobacteria/Rickettsiales | 20 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Alphaproteobacteria/Others | 63 | 7 | 3 | 5 | 5 | - | - | 3 | 2 | 2 | 1 | - | 1 | 11 | 5 | 11 | 30 |
| Alphaproteobacteria/Rhizobiaceae | 5 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 4 | 4 |
| Betaproteobacteria/Bordetella | 3 | - | - | - | - | - | - | - | - | - | - | - | - | 3 | - | - | - |
| Betaproteobacteria/Burkholderiaceae | 20 | - | - | - | - | - | - | 3 | 9 | 10 | - | - | - | 5 | - | - | 5 |
| Betaproteobacteria/Neisseriaceae | 3 | - | - | - | - | - | - | - | 1 | - | - | - | - | 1 | - | - | - |
| Betaproteobacteria/Others | 19 | 1 | 1 | 1 | - | - | - | 1 | - | - | - | - | 1 | 10 | - | - | 6 |
| Gammaproteobacteria/Enterobacteriales | 25 | - | 9 | - | 17 | - | - | 16 | - | - | - | - | - | - | - | - | - |
| Gammaproteobacteria/Pasteurellaceae | 8 | 3 | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - |
| Gammaproteobacteria/Vibrionaceae | 12 | - | - | - | 1 | - | - | - | - | - | - | - | - | 5 | - | - | - |
| Gammaproteobacteria/Pseudomonadaceae | 8 | - | - | - | 1 | - | - | - | - | - | - | - | - | 8 | - | - | 6 |
| Gammaproteobacteria/Xanthomonadaceae | 5 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Gammaproteobacteria/Others | 62 | 1 | 3 | 1 | 4 | - | - | 1 | - | - | 1 | 1 | 1 | 20 | - | 7 | 4 |
| Proteobacteria/Others | 2 | - | 1 | - | - | - | - | - | - | - | 1 | - | - | - | - | - | - |
| Total | 540 | 52 | 66 | 55 | 44 | 2 | 0 | 30 | 16 | 28 | 9 | 1 | 12 | 65 | 15 | 23 | 87 |
*: N, number of organisms containing Ni-specific transporter; C, number of organisms containing Co-specific transporter; U, number of organisms containing transporters with unassigned function;
**: Other predicted Co transporters include CbtAB, CbtC, CbtD, CbtE, CbtF, CbtG and CbtX.