BIOL 2004 Lecture Notes - Lecture 7: Crenarchaeota, Euryarchaeota, Microaerophile

• School: Dalhousie University
• Department: Biology
• Course: BIOL 2004
• Professor: Simpson Alastair

Document Summary

What are archaea: prokar(cid:455)oti(cid:272) (cid:272)ells like ba(cid:272)teria, (cid:271)ut, se(cid:448)eral (cid:272)hara(cid:272)teristi(cid:272) (cid:858)ar(cid:272)haeal(cid:859) features, a(cid:374)d so(cid:373)e features shared (cid:449)ith eukar(cid:455)otes (cid:894)to the e(cid:454)(cid:272)lusio(cid:374) of bacteria, ma(cid:374)(cid:455) are e(cid:454)tre(cid:373)ophiles. Three domains of life: bacteria, archaea, eukaryotes. Archaea: fundamentally, prokaryotes: usuall(cid:455) s(cid:373)all (cid:272)ells, fe(cid:449) i(cid:374)ter(cid:374)al (cid:272)ell stru(cid:272)tures, usuall(cid:455) si(cid:374)gle (cid:272)ir(cid:272)ular (cid:272)hro(cid:373)oso(cid:373)e + opero(cid:374)s, coupled tra(cid:374)s(cid:272)riptio(cid:374) a(cid:374)d tra(cid:374)slatio(cid:374) Some important differences from bacteria: example characteristic archaeal features, cell membrane & envelope composition. Standard membrane lipids in bacteria (and eukaryotes: fatty acids, d-glyceride, ester (acid-alcohol) linkages. Archaeal cell membrane lipids: isopre(cid:374)oids (cid:894)asse(cid:373)(cid:271)led fro(cid:373) isopre(cid:374)e u(cid:374)its(cid:895) =(cid:858)(cid:271)ra(cid:374)(cid:272)hed (cid:272)hai(cid:374) lipids(cid:859, stereo(cid:272)he(cid:373)i(cid:272)all(cid:455) differe(cid:374)t (cid:894)l-glycerides, not d-glycerides, ether li(cid:374)kages (cid:894)rather tha(cid:374) ester-linkages) No outer membrane: (cid:858)pseudo peptidogl(cid:455)(cid:272)a(cid:374)(cid:859) (cid:272)ell (cid:449)all i(cid:374) so(cid:373)e, (cid:858)s-la(cid:455)ers(cid:859) (cid:272)o(cid:373)(cid:373)o(cid:374) (cid:894)le(cid:272)ture (cid:1005)(cid:895) Some important differences from bacteria: some eukaryote-like features. Eukaryote-like features: transcription machinery: eukar(cid:455)ote-like many-subunit rna polymerase, eukar(cid:455)ote-like transcription factors, e(cid:272)og(cid:374)ise eukar(cid:455)ote-like promoters. Eukaryote-like features: translation machinery: ma(cid:374)(cid:455) eukar(cid:455)ote-archaea-specific ribosomal proteins, methio(cid:374)i(cid:374)e as i(cid:374)itiator a(cid:373)i(cid:374)o a(cid:272)id (cid:894)ba(cid:272)teria use n-formylmethionine [fmet], eukar(cid:455)ote-like translation initiation & elongation factors.