Lysis ( ) is the breaking down of the membrane of a cell, often by viral, enzymic, or

osmotic Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region ...

(that is, "lytic" ) mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a ''lysate''. In

molecular biology Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and phys ...

biochemistry Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...

, and cell biology laboratories, cell cultures may be subjected to lysis in the process of purifying their components, as in

protein purification Protein purification is a series of processes intended to isolate one or a few proteins from a complex mixture, usually cells, tissues or whole organisms. Protein purification is vital for the specification of the function, structure and interact ...

, DNA extraction, RNA extraction, or in purifying organelles. Many species of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

are subject to lysis by the enzyme lysozyme, found in animal saliva, egg white, and other secretions. Phage lytic enzymes (

lysin Lysins, also known as endolysins or murein hydrolases, are hydrolytic enzymes produced by bacteriophages in order to cleave the host's cell wall during the final stage of the lytic cycle. Lysins are highly evolved enzymes that are able to target ...

s) produced during

bacteriophage A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bac ...

infection are responsible for the ability of these viruses to lyse bacterial cells.

Penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from '' Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum usin ...

and related β-lactam

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

s cause the death of bacteria through enzyme-mediated lysis that occurs after the drug causes the bacterium to form a defective cell wall. If the cell wall is completely lost and the penicillin was used on gram-positive bacteria, then the bacterium is referred to as a protoplast, but if penicillin was used on gram-negative bacteria, then it is called a spheroplast.

Cytolysis

Cytolysis occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell. Cytolysis can be prevented by several different mechanisms, including the

contractile vacuole A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae. It was previously known as pulsatile or pulsating vacuole. Overview The contractile va ...

that exists in some paramecia, which rapidly pump water out of the cell. Cytolysis does not occur under normal conditions in plant cells because plant cells have a strong cell wall that contains the osmotic pressure, or turgor pressure, that would otherwise cause cytolysis to occur.

Oncolysis

Oncolysis is the destruction of neoplastic cells or of a

tumour A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

. The term is also used to refer to the reduction of any swelling.

Plasmolysis

Plasmolysis is the contraction of cells within plants due to the loss of water through

osmosis Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region ...

. In a

hypertonic In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two solutions separated by a partially-permeable cell membrane. Tonicity depends on the relative concentration of selective membrane- ...

environment, the cell membrane peels off of the cell wall and the

vacuole A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic m ...

collapses. These cells will eventually wilt and die unless the flow of water caused by osmosis can stop the contraction of the

cell membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (t ...

Immune response

Erythrocytes' hemoglobin release free radicals in response to pathogens when lysed by them. This can damage the pathogens.

Applications

Cell lysis is used in laboratories to break open cells and purify or further study their contents. Lysis in the laboratory may be affected by

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s or detergents or other chaotropic agents. Mechanical disruption of cell membranes, as by repeated freezing and thawing, sonication, pressure, or filtration may also be referred to as lysis. Many laboratory experiments are sensitive to the choice of lysis mechanism; often it is desirable to avoid mechanical shear forces that would denature or degrade sensitive macromolecules, such as

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

s and DNA, and different types of detergents can yield different results. The unprocessed solution immediately after lysis but before any further extraction steps is often referred to as a ''crude lysate''. For example, lysis is used in western and Southern blotting to analyze the composition of specific

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

lipids Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids in ...

, and nucleic acids individually or as complexes. Depending on the detergent used, either all or some membranes are lysed. For example, if only the

is lysed then gradient centrifugation can be used to collect certain organelles. Lysis is also used for

, DNA extraction, and RNA extraction.

Methods

Chemical lysis

This method uses chemical disruption. It is the most popular and simple approach. Chemical lysis chemically deteriorates/solubilizes the proteins and lipids present within the membrane of targeted cells.

Acoustic lysis

This method uses ultrasonic waves to generate areas of high and low pressure which causes cavitation and in turn, cell lysis. Though this method usually comes out clean, it fails to be cost effective and consistent.

Mechanical lysis

This method uses physical penetration to pierce or cut a cell membrane.

References

{{Reflist Cell biology Cell death