Hello Xi Su

Yes, you may use Hoechst 33342 for mycoplasma screening.

Hoechst 33342 is a cell permeable fluorescent compound that is able to stain the DNA of eukaryotic as well as prokaryotic cells by binding with high affinity to the minor groove of AT-rich DNA sequences. Both Hoechst 33258 and Hoechst 33342 are very closely related bis-benzimides dyes, and are excited by ultraviolet light at around 350 nm, and both emit blue/cyan fluorescence light around an emission maximum at 461 nm. The key difference between them is that the additional ethyl group of Hoechst 33342 renders it more lipophilic, and thus more able to cross intact cell membranes. Hoechst 33258 is significantly less permeant.

You may use Hoechst 33342 for mycoplasma screening. Please refer to the link below. See page 28.

https://www.uab.cat/doc/ATCCguide

Hoechst 33342 is commonly used as a DNA binding dye to determine cell cycle status and apoptosis assays.

Best.