Acrasidae

Acrasidae

Acrasidae is a family of slime molds within the order Acrasiales. These organisms are notable for their unique life cycle, which includes both unicellular and multicellular stages. Acrasidae are often studied in the context of cellular differentiation and evolutionary biology due to their intriguing transition from single-celled amoebae to a multicellular structure.

Characteristics

Acrasidae are characterized by their ability to exist as free-living amoeboid cells that can aggregate to form a multicellular structure known as a pseudoplasmodium or "slug." This aggregation is typically triggered by environmental cues such as nutrient depletion. The slug migrates to a suitable location where it forms a fruiting body, allowing for spore dispersal.

Life Cycle

The life cycle of Acrasidae involves several distinct stages:

1. **Amoeboid Stage**: The organism exists as individual amoebae that feed on bacteria and other microorganisms in the soil.
2. **Aggregation**: When food becomes scarce, the amoebae release signaling molecules, such as cyclic AMP, which attract other amoebae to aggregate.
3. **Slug Formation**: The aggregated amoebae form a slug-like structure that can move towards light or heat.
4. **Fruiting Body Formation**: The slug eventually forms a fruiting body, which consists of a stalk and spores. The spores are released into the environment to germinate into new amoebae when conditions are favorable.

Habitat

Acrasidae are typically found in soil, leaf litter, and other decaying organic matter. They play a role in the ecosystem as decomposers, breaking down organic material and recycling nutrients.

Taxonomy

The family Acrasidae belongs to the class Heterolobosea within the phylum Percolozoa. It includes several genera, such as Acrasis and Guttulinopsis.

Research and Importance

Acrasidae are of interest to researchers studying developmental biology and evolution. Their ability to transition from unicellular to multicellular forms provides insights into the evolution of multicellularity. Additionally, the signaling mechanisms used during aggregation are studied for their similarities to processes in higher organisms.

Also see

• Slime mold
• Cellular differentiation
• Multicellularity
• Heterolobosea
• Percolozoa