Microbial cell membrane and envelope

The microbial cell membrane and envelope represent the fundamental structural barriers of bacteria and fungi, providing protection against environmental stress and maintaining cellular homeostasis (Silhavy et al., 2010, Cold Spring Harb Perspect Biol). In bacteria, the envelope is composed of the inner cytoplasmic membrane and a peptidoglycan cell wall, while Gram-negative species also feature an asymmetric outer membrane (Kohanski et al., 2010, Nat Rev Microbiol). These structures are essential for viability, as they regulate osmotic pressure and house the machinery for nutrient uptake and protein secretion. Because the biochemical composition of these envelopes—such as peptidoglycan in bacteria and ergosterol in fungi—is distinct from mammalian cells, they are primary targets for many classes of antibiotics and antifungals (Odds et al., 2003, J Antimicrob Chemother). Drugs targeting the envelope work by either inhibiting the synthesis of its components, such as beta-lactams and glycopeptides, or by physically disrupting the membrane bilayer, as seen with polymyxins and daptomycin (Poirel et al., 2017, Clin Microbiol Rev).

Other names

Bacterial cell envelopeFungal cell wallCytoplasmic membraneOuter membranePlasma membranePeptidoglycan layer

Inhibition of peptidoglycan biosynthesis and cross-linking, disruption of cytoplasmic membrane integrity and potential, pore formation in the lipid bilayer, and inhibition of fungal cell wall components like beta-glucan.