pseudoplasmodia

A pseudoplasmodium is a stage in the life cycle of certain social amoebas, most notably in the genus Dictyostelium. Unlike a true plasmodium, which is a single multinucleated cell, a pseudoplasmodium is an aggregation of individual amoeboid cells that come together to form a multicellular structure. This aggregation is a coordinated response to starvation or other environmental cues. Individual amoebas, which normally exist independently, begin to move towards each other and stream together, forming a slug-like mass. This mass, the pseudoplasmodium, is migratory and can move across the substrate in search of a more favorable location for spore formation. The cells within the pseudoplasmodium maintain their individual cell walls and identities, but their behavior is highly coordinated. This collective movement and differentiation is a remarkable example of social behavior in unicellular organisms. Following migration, the pseudoplasmodium differentiates further, typically forming a fruiting body composed of a stalk and spore-containing sorus. The cells that form the stalk are usually sterile, while the cells that form the spores are reproductive. This transition from individual cells to a multicellular, differentiated organism highlights a unique evolutionary pathway in the development of multicellularity.