Hi everyone,
still very strange. I did some tests as written in the post above … all look essentially identical. Actin is only stained at the outer border of the coverslip.
This time I included a tubulin-antibody staining. Tubulin staining looks great on the whole coverslip.
Phalloidin647 was incubated together with the secondary antibody.
This phenomenon shows some consistency now, but it´s nothing I have ever seen in the last 10 years.
Any further suggestion is appreciated.
Martin