Bacterial and fungal cell membranes and viral envelopes

Microbial lipid membranes and envelopes serve as the primary physical barrier between pathogens and their environment, maintaining internal homeostasis and regulating the transport of ions and nutrients. In bacteria, the cytoplasmic membrane and the outer membrane of Gram-negative species are essential for viability, containing unique components like lipopolysaccharides that are targeted by antibiotics such as polymyxins and daptomycin (Source: Nature Reviews Microbiology, 2017). Fungal membranes are distinguished by the presence of ergosterol, a sterol absent in human cells, which provides a selective target for polyene antifungals like amphotericin B that induce pore formation and subsequent cell death (Source: Journal of Fungi, 2020). Viral envelopes, which are lipid bilayers derived from host cells but embedded with viral proteins, are critical for protecting the viral genome and facilitating host cell entry. Therapeutic agents that disrupt these envelopes or inhibit their fusion with host membranes can effectively neutralize viral infectivity (Source: Antiviral Research, 2018). Because these structures are fundamental to pathogen survival and often differ significantly in composition from human cell membranes, they represent high-value targets for antimicrobial and antiviral drug development.

Other names

Microbial lipid bilayersPathogen cell membranesViral lipid envelopesCytoplasmic membranesOuter membranes (Gram-negative)

Drugs targeting these structures typically act through physical disruption of the lipid bilayer, formation of transmembrane pores, or depolarization of the membrane potential. For example, polyenes bind to ergosterol in fungal membranes to create leaky pores, while polymyxins interact with lipopolysaccharides in bacterial outer membranes to increase permeability (Source: StatPearls, Amphotericin B; PubMed, PMID: 27335449). Some agents also inhibit the fusion of viral envelopes with host cell membranes to prevent infection (Source: Antiviral Research, 2018).