TABLE 1.
Growth and fruiting body formation for M. xanthus strain HW-1 on VY/2 agar containing different combinations of the three main seawater salts
| NaCl concn (%) | MgCl2 concn (%) | CaCl2 concn (%) | Generation time (h) | Fruiting body formationa | Sporulation frequency (per 104 cells)b |
|---|---|---|---|---|---|
| 0-0.5 | 0 | 0 | 10 | ++ | 20 |
| 1.0-1.5 | 0 | 0 | 8 | + | 10 |
| 2.0-2.5 | 0 | 0 | 15 | ± | 0.04 |
| 3.0 | 0 | 0 | NGc | ||
| 0-0.5 | 0.05 | 0.05 | 8 | ++ | 32 |
| 1.0-1.5 | 0.05 | 0.05 | 7 | + | 16 |
| 2.0-2.5 | 0.05 | 0.05 | 16 | + | 2.5 |
| 3.0 | 0.05 | 0.05 | 18 | ± | 0.2 |
| 4.0 | 0.05 | 0.05 | 24 | − | 0 |
| 0 | 0 | 0.05 | 11 | ± | 0.5 |
| 0 | 0.1-2.5 | 0.05 | 10 | ++ | 50 |
| 0 | 0.05 | 0-0.1 | 10 | ++ | 12.6 |
| 0 | 0.05 | 0.5 | 18 | + | 4.0 |
| 0 | 0.05 | 1.0-1.5 | 23 | ± | 0.04 |
| 0 | 0.05 | 2.0 | NG | ||
| Seawater (100% HVY) | 21 | ± | 2.0 |
a
++, complete fruiting bodies; +, rudimentary fruiting bodies; ±, cell mounds; −, no fruiting bodies.
b
The sporulation frequencies reflect the proportion of cells in starving populations that formed heat-resistant spores after development. For details see Materials and Methods.
c
NG, no growth or weak growth.