[Differentiation processes in the germinating Gemmula ofEphydatia fluviatilis]

Area of Science:

• Cellular biology
• Developmental biology
• Invertebrate zoology

Context:

• Focuses on the dormant gemmulae of the freshwater sponge *Ephydatia fluviatilis*.
• Examines the totipotent statocytes (thésocytes) within these gemmulae.
• Investigates early developmental processes in sponges.

Purpose:

• To elucidate the differentiation potential of statocytes in *Ephydatia fluviatilis* gemmulae.
• To describe the spatial organization of cells during sponge primordium formation.
• To understand the initial steps of regeneration in freshwater sponges.

Summary:

• Uniform, totipotent statocytes in *Ephydatia fluviatilis* gemmulae differentiate into archaeocytes or histoblasts.
• Histoblasts aggregate near the micropyle, while other cells orient along a developmental gradient.
• A sponge primordium, comprising various cell types, is released and develops into a new sponge.

Impact:

• Provides insights into totipotency and cell differentiation in primitive multicellular organisms.
• Contributes to understanding asexual reproduction and regeneration mechanisms in sponges.
• Highlights the role of cellular organization in early developmental patterning.