%0 Journal Article %A Kosugi, Taitiro %A Inouye, Kei %T Negative Chemotaxis to Ammonia and Other Weak Bases by Migrating Slugs of the Cellular Slime Moulds %D 1989 %J Microbiology, %V 135 %N 6 %P 1589-1598 %@ 1465-2080 %R https://doi.org/10.1099/00221287-135-6-1589 %I Microbiology Society, %X Ammonia is known to be a repellent gas for rising sorogens of Dictyostelium discoideum, and it has been suggested that it is also a repellent gas for migrating slugs of the same species. Here we present evidence that migrating slugs of D. discoideum and two related species, D. mucoroides and Polysphondylium violaceum, indeed orient away from high concentrations of NH3. In D. discoideum, brief exposure of a slug to an NH3 gradient of about 1 p.p.m. mm−1 (10−5 atm cm−1 or 0·00076 mmHg mm−1) was sufficient to alter the direction of its migration. The gases of other weak bases, such as methylamine, trimethylamine, ethylamine and pyrrolidine, were also effective. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-135-6-1589