lyse

Lysis is the disintegration or rupture of a cell or its contents, typically resulting from rupture of the cell membrane, cell wall, or both. The term derives from the Greek lysis, meaning loosening or breaking apart. Lysis can occur through physical, chemical, enzymatic, or biological processes and is a central concept across biology, medicine, and biotechnology.

In biological contexts, lysis refers to the breakdown of cells due to osmotic pressure, toxins, detergents, mechanical damage, or enzymatic digestion of structural components. Osmotic lysis happens when cells are placed in a hypotonic environment and take up water until the membrane fails. Plant and bacterial cells respond differently because of cell walls, but they can still undergo lysis under extreme conditions or with specific agents.

In virology and bacteriology, lysis is a hallmark of the lytic life cycle. Lytic viruses replicate inside a host cell and produce enzymes that degrade the cell wall or membrane, enabling the release of new virions. Bacteriophages commonly employ holins to form pores in the membrane and endolysins to degrade peptidoglycan, leading to cell rupture. Complement-mediated lysis is an immune mechanism in which the membrane attack complex creates pores in target cell membranes.

In clinical and laboratory settings, hemolysis describes the destruction of red blood cells and the release of hemoglobin, which can be an indicator of disease or a result of sample handling. Lysis is also exploited in molecular biology and biochemistry to extract DNA, RNA, proteins, or organelles from cells using detergent-based, enzymatic, or osmotic methods.

Etymology and related terms: lysis is contrasted with lytic processes and also with lysogenesis, where the lysogenic cycle integrates viral DNA into the host genome rather than causing immediate lysis.