Sexual pheromone accumulation and response in agar plate and liquid cultures of Dictyostelium discoideum

Abstract

Sexual development in the mated cultures of Dictyostelium discoideum is initiated by one or more pheromones. In agar plate cultures of NC4, the presence of the pheromone becomes detectable by 22 h and reaches its maximal activity by 24 h. Cells of V12 from plate cultures also reach their maximal responsiveness at 24 h. In liquid culture, the NC4 pheromonal activity is detectable by 10 h and increases to a maximum at 15 h before declining so that by 30 h no activity is detectable. The V12 cells develop the competence to respond to the pheromone by 10 h and increase to a peak responsiveness by 15 h after which they lose the ability to respond. These data support earlier experiments demonstrating that sexual pheromones exist in the cellular slime moulds. The results of the liquid culture experiments in which the pheromonal induction of macrocyst formation reaches levels equivalent to 30% of mated cultures (NC4 × V12) also suggest that this pheromone bioassay system is sensitive enough to permit the isolation and characterization of the sexual pheromones of D. discoideum.

Signalling and sex in the social amoebozoans

“…The volatile nature of this inducer verifying it as a true sex pheromone was shown when NC4 cultures induced V12 cells to form macrocysts when both culture dishes were separated by a moat of detergent so that cells could only communicate via a common airspace (O’Day & Lewis, 1975; Lewis & O’Day, 1977). Since NC4 produces the most gamete cells and since pheromone accumulation coincides with their appearance, it is possible that gametes are the source of the pheromone (Morris, Lewis & O’Day, 1982; O’Day et al , 1987). Various types of pheromone‐regulated mating interactions have been reported in the heterothallic species D. purpureum and D. giganteum (Lewis & O’Day, 1976, 1979; O’Day & Lewis, 1981).…”

Pheromones do regulate sexual development in Dictyostelium discoideum

“…() who argue that physical contact between mating types is essential for macrocyst formation. Our laboratory is one of the few laboratories internationally that has been studying all aspects of sexual development in the social amoebozoans for several decades, and we reached our conclusions regarding the importance of pheromones as initiating agents through a diversity of techniques carried out by several different researchers (O'Day & Lewis, ; Lewis & O'Day, , , ; Morris et al ., ; O'Day et al ., ). Cell contact between mating types is not essential for sexual development (i.e., macrocyst formation).…”