Cell lysis is a process in which a cell is broken down or destroyed as a result of some external force or condition. Lysis can happen through natural means, such as viral infections, or through artificial means for research purposes. The resulting substance that contains the previous contents of the destroyed cell is referred to as the lysate; a substance that causes lysis, particularly an antibody, is called a lysin.
Simple osmosis is one of the most common causes of cell lysis in plants and in animals. In cytolysis, the cell has a higher salt concentration that its surroundings, so water flows into the cell through osmosis, causing it to burst. In plasmolysis, on the other hand, the cell loses water through osmosis because of evaporation or because of a high salt concentration outside of the cell. This process eventually causes lysis as the cell shrivels and dies. Plasmolysis is particularly common in plant cells which often lose significant amounts of water because of hot, dry conditions.
It is not uncommon to intentionally induce cell lysis during the course of an experiment or research project. There are many different methods used to cause lysis; the specific method used is based on the needs of the particular experiment. When one needs to cause lysis in large numbers of cells or in a clump of solid tissue, mechanical methods such as spinning blades or blenders are sometimes useful. Another method is sonication, in which high-frequency sound waves are used to disrupt and destroy cells. A third method involves repeatedly freezing and thawing groups of cells with the goal of forming ice crystals that will penetrate the cells.
Cell lysis falls into the broad category of cell disruption, which describes processes that release the biological material that exists within the cell. There are many different lab techniques that are used to cause cell disruption as well. Enzymes, for example, are commonly used to remove cell walls in preparation for further cellular disruption which may include eventual cell lysis.
Bacterial cells are often destroyed through cell lysis because of the action of certain enzymes that are common in the saliva, tears, and mucous of various animals. These enzymes are typically referred to as lysozymes. Lysozymes play an important role in the human immune system; low levels of lysozymes have been correlated with increased instances of bacterial infection. These enzymes attack the bonds that hold the cell walls and other structures of bacterial cells together, eventually causing lysis.