lysing

Lysing, or lysis, is the process by which a cell or cellular structure breaks open and releases its contents. It encompasses disruption of cell membranes or walls due to physical, chemical, enzymatic, or osmotic forces. The term is used across biology, medicine, and biotechnology to describe both natural and deliberate disruption of cells.

In nature, lysing occurs during viral infection when a bacteriophage’s replication ends with host cell lysis, releasing progeny viruses. In animals, hemolysis is a form of lysing where red blood cells rupture and release hemoglobin. Osmotic lysis happens when cells are placed in hypotonic solutions, causing influx of water and swelling to the point of rupture.

In laboratory practice, lysing is used to access intracellular components such as DNA, RNA, or proteins. Methods include osmotic lysis with hypotonic buffers; enzymatic lysis using lysozyme (especially for bacteria) or proteases; chemical lysis with detergents (for example SDS or Triton X-100); and mechanical disruption by sonication or homogenization. Alkaline lysis is a common protocol for plasmid DNA purification, exploiting differential release of plasmid versus chromosomal DNA.

Unintended lysing can contribute to tissue injury and disease, such as hemolysis during blood transfusion reactions or reperfusion injury after ischemia. In research, careful control of lysing conditions is essential to preserve desired biomolecules and to prevent contamination from cellular debris.

See also: lysis, lytic cycle, hemolysis.