Lysis (biology)
The lysis (from the French from the learned Greek λ σις , "[dissolution]"; also original lysis ) describes in biology and medicine the disintegration of a cell through damage or dissolution of the outer cell membrane ( necrosis ).
In principle, this occurs with all conceivable tissue damage with cell death, but is of particular importance in the following situations:
- As part of the so-called programmed cell death , the physiological, u. a. hormonally mediated and genetically controlled apoptosis z. B. during growth, maturation and tissue differentiation, there is ultimately lysis of old, superfluous or obstructive cells in the tissue network.
- The healthy immune system uses special T lymphocytes , so-called cytotoxic killer cells, for example, to ensure that degenerate tumor cells or host cells containing viruses or parasites that are identified as infected are lysed and quickly broken down.
- However, the undisturbed replication cycle of many viruses, the infection cycle, ends with the lytic rupture of the host cell's cell membrane, but then without preferential breakdown of the remains: only then are the virus particles that have matured in the cell released into the environment.
- In biological research ( biochemistry , molecular biology , cell biology ), lysis is also the active breaking up of cells from tissue or cell culture in order to access proteins and DNA inside the cell. The cells are lysed by mechanical means ( vortex mixer , ultrasound, etc.) and / or chemical means ( sodium hydroxide solution, etc.). The result is known as the lysate and can be used for follow-up experiments or in the manufacture of drugs. Hypotonic lysis is often used for subsequent cell fractionation .
In medical jargon , lysis is also short for thrombolysis , a mostly drug-based therapy against blood clots , often used in emergency medicine if a heart attack is suspected to be just a few hours old or if there is a pulmonary embolism , even in the case of a recent, confirmed, non-bleeding-related stroke .