BIO 3124 Lecture Notes - Lecture 4: Amphiphile, Facilitated Diffusion, Gram-Negative Bacteria

• School: University of Ottawa
• Department: Biology
• Course: BIO 3124
• Professor: John Basso

Document Summary

Acid fast staining: for micro bacteria, this stain will only stain micro bacteria, typically they have a cell wall with mycolic acid. First need to make the cell wall permeable, to do this we add heat. By adding heat we can use a basic fustian stain, which can go through permeable cell wall, target is the cell membrane. Cool cells back down so cell wall is impermeable again and stain is trapped. Following the cooling we do an alcohol wash (like gram stain technique) this is the differential step, use a(cid:374) a(cid:272)idi(cid:272) al(cid:272)ohol (cid:894)(cid:373)u(cid:272)h (cid:373)ore harsh(cid:895) this (cid:272)a(cid:374)"t rea(cid:272)h (cid:272)ell (cid:373)e(cid:373)(cid:271)ra(cid:374)e, so al(cid:272)ohol (cid:272)a(cid:374)"t (cid:271)reak ele(cid:272)trostatic interaction, cell remains fuchsia. If (cid:455)ou"re a (cid:373)(cid:455)(cid:272)o(cid:271)a(cid:272)teria it (cid:449)o(cid:374)"t rea(cid:272)h the (cid:272)ell (cid:373)e(cid:373)(cid:271)ra(cid:374)e, a(cid:374)(cid:455)thi(cid:374)g else (cid:455)ou (cid:449)ill ha(cid:448)e the se(cid:272)o(cid:374)d (cid:272)olour o(cid:374) that (cid:271)a(cid:272)teria. Typically mycobacteria are gram positive, this reason (based on same principal) they trap the main stain, this is (cid:449)h(cid:455) the(cid:455)"re (cid:272)alled gra(cid:373) positi(cid:448)e.