Stromulus

Fluorescence microscope image of an onion epidermis cell that has been transformed with GFP which has been introduced into the plastids via a corresponding transit peptide . Several stroma are clearly visible

Stromuli (singular Stromulus , from Engl. Stromule , short for stroma filled tubules - stroma -filled tubes) are tube-like protuberances of the plastids in plant cells . They are surrounded by both membranes of the plastid and contain stroma, including typical stroma proteins such as Rubisco , but no thylakoids . Stromuli often connect different plastids with one another or extend to other organelles such as mitochondria , the cell nucleus or the plasma membrane . It is therefore assumed that the stromules could be involved in communication or exchange of substances within the cell. It has been proven that proteins can be exchanged between different plastids via stromules.

Stromuli are highly dynamic structures that can form, deform, branch or even disintegrate into vesicles within a short period of time . Here Stromuli probably have contact through myosins for actin - cytoskeleton , allowing their mobility and orientation.

literature

• Karin Krupinska, Christine Desel, Maria Mulisch: Stromuli. Plastid bridges in the cell network . In: Biology in Our Time . tape 40 , no. 3 , 2010, p. 162-170 .