Figure 3. Phalloidin staining using non-optimal conditions.

A. If cells incubate too long in staining solution or PFA has expired, cells will show strong pyrenoid signal (yellow arrow) and non-specific cytoplasmic staining. This type of signal can be easily distinguished from Atto 488 signal as there will be no filamentous perinuclear or apical staining, instead a dim hazy signal found throughout the entire cell body as pictured in A and B above. Scale bars = 5 μm. C. A general diagram of a Chlamydomonas cell highlighting filamentous actin in pink, the pyrenoid in blue, and the chloroplast in green.