Akinete

An akinete is a dormant, thick-walled, non-motile, and metabolically inactive cell formed by certain cyanobacteria (blue-green algae) under unfavorable environmental conditions, such as nutrient limitation, temperature extremes, desiccation, or light deprivation.

Akinetes are considered resting cells, and their primary function is survival and the perpetuation of the cyanobacterial population when conditions are not conducive to vegetative growth. They are larger than vegetative cells and possess a thickened cell wall composed of multiple layers, providing resistance to environmental stresses. These walls often contain specific compounds that further enhance their durability.

The formation of akinetes involves significant changes in the cell's physiology, including an increase in the storage of energy reserves like glycogen and cyanophycin. They have a reduced metabolic rate, allowing them to persist for extended periods, potentially months or even years, depending on the species and environmental conditions.

When favorable conditions return, akinetes germinate, resuming vegetative growth and re-establishing the cyanobacterial population. Germination involves the breaking of the akinete wall and the emergence of a new vegetative cell. The ability to form akinetes is a crucial adaptation that allows cyanobacteria to thrive in fluctuating environments.