From: Comparative genomic analyses of nickel, cobalt and vitamin B12 utilization
 |  | Archaea | Bacteria | Eukarya | Total |
---|---|---|---|---|---|
Ni-utilizing organisms | Â | 39 | 319 | 51 | 409 |
Ni User (+) | Ni Transporter* (+) | 21 | 166 | 49 | 236 |
 | Ni Transporter (-) & Unassigned transporter (+) | 11 | 81 | - | 92 |
 | Ni Transporter (-) & Unassigned transporter (-) | 7 | 62 | 2 | 71 |
Ni User (-) | Ni Transporter (+) | - | 10 | - | 10 |
Co-utilizing organisms | Â | 45 | 410 | 49 | 504 |
B 12 biosynthesis pathway (+) | Co Transporter (+) | 15 | 180 | - | 195 |
 | Co Transporter (-) & Unassigned transporter (+) | 10 | 16 | - | 26 |
 | Co Transporter (-) & Unassigned transporter (-) | 9 | 13 | - | 22 |
B 12 biosynthesis pathway (-) | Co Transporter (+) | - | - | - | - |
Other (using external B 12 ) | Â | 11 | 201 | 49 | 261 |
Organisms that use both Ni and Co | Â | 38 | 287 | 9 | 335 |
Organisms that use neither Ni nor Co | Â | 1 | 98 | 69 | 168 |