Lysis (Greek λύσις, lýsis from lýein "to separate") refers to the breaking down of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a "lysate".

Many species of bacteria are subject to lysis by the enzyme lysozyme, found in animal saliva, egg white, and other secretions.[1] Phage lytic enzymes (lysins) produced during bacteriophage infection are responsible for the ability of these viruses to lyse bacterial cells.[2] Penicillin and related β-lactam antibiotics cause the death of bacteria through enzyme-mediated lysis that occurs after the drug causes the bacterium to form a defective cell wall.[3] If cell wall is completely lost, the bacterium is referred as a protoplast if penicillin was used on gram-positive bacteria, and spheroplast when used on gram-negative bacteria.



Cytolysis is the lysis of cells in a hypotonic environment (the surrounding fluid has a lower salt concentration than the cell interior). Cytolysis is caused by excessive osmosis, or movement of water, towards the inside of a cell (hyperhydration). The cell membrane cannot withstand the osmotic pressure of the water inside, and so it explodes. Osmosis occurs from a region of high water potential to a region of low water potential passing through a semipermeable membrane, so these bursting cells are located in hypotonic environments.

Cytolysis can be prevented by several different mechanisms, including the contractile vacuole 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.



Plasmolysis is the contraction of cells within plants due to the loss of water through osmosis. In a hypertonic environment, the cell membrane peels off of the cell wall and the vacuole collapses. These cells will eventually wilt and die unless the flow of water caused by osmosis can stop the contraction of the cell membrane.[4]

Immune response

Main article: Red blood cell#Secondary functions

Erythrocytes' hemoglobin release free radicals in response to pathogens when lysed by them. This can damage the pathogens.[5][6]


Cell lysis (splitting of cells) is used to break open cells when it is desirable to avoid shear forces that would denature or degrade sensitive macromolecules, such as proteins and DNA. For example, lysis is used in western and Southern blotting to analyze the composition of specific proteins, lipids, and nucleic acids individually or as complexes. Depending upon the detergent used, either all or some membranes are lysed. For example, if the cell membrane only is lysed then gradient centrifugation can be used to collect certain organelles.


  1. ^ Fastrez, J. Phage Lysozymes In: Lysozymes--model enzymes in biochemistry and biology, Pierre Jollès editor, Birkhäuser, 1996, pp. 35-64.
  2. ^ Nelson, D., Loomis, L. & Fischetti, V. A. (2001). Prevention and elimination of upper respiratory colonization of mice by group A streptococci by using a bacteriophage lytic enzyme. Proceedings of the National Academy of Sciences, USA 98, 4107–12.
  3. ^ Scholar, E. M., Pratt W. B. The antimicrobial drugs, Oxford University Press US, 2nd ed., 2000, pp. 61-64.
  4. ^ "Wiley InterScience : Journals : New Phytologist". Retrieved 2008-09-11. 
  5. ^ Red blood cells do more than just carry oxygen. New findings by NUS team show they aggressively attack bacteria too., The Straits Times, 1 September 2007
  6. ^ Jiang N, Tan NS, Ho B, Ding JL (October 2007). "Respiratory protein-generated reactive oxygen species as an antimicrobial strategy". Nature Immunology 8 (10): 1114–22. doi:10.1038/ni1501. PMID 17721536. 

See also

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Look at other dictionaries:

  • Lysis — Lysis, dans le lécythe pour son fils Timocléide (IVe siècle A.C). Le Lysis (ou Sur l’Amitié ; Λύσις en grec) est un dialogue de Platon. Il appartient à la série dite des « Premiers Dialogues  …   Wikipédia en Français

  • Lysis — ist sowohl ein altgriechischer Eigenname als auch ein Begriff. Der Begriff (griechisch λύσις, lýsis, „Lösung, Auflösung, Beendigung“; Alternativform: Lyse über das Französische) steht für das Auflösen einer Zelle, siehe Lyse (Biologie) die… …   Deutsch Wikipedia

  • lysis — (n.) dissolution of cells, bacteria, etc., 1902, from L. lysis, from Gk. lysis a loosening, from lyein to unfasten, loose, loosen, untie (see LOSE (Cf. lose)) …   Etymology dictionary

  • -lysis — [lə sis, lisis] [< Gr lysis: see LYSIS] combining form a loosening, dissolution, dissolving, destruction [catalysis, electrolysis] …   English World dictionary

  • Lysis — Ly sis (l[imac] s[i^]s), n. [NL., fr. Gr. ly sis.] (Med.) The resolution or favorable termination of a disease, coming on gradually and not marked by abrupt change. [1913 Webster] Note: It is usually contrasted with crisis, in which the… …   The Collaborative International Dictionary of English

  • lysis — ● lysis nom masculin (grec lusis, action de délier) Allure progressivement décroissante d une courbe thermique. lysis [lizis] n. m. ÉTYM. 1839; archit., 1547; grec lusis. → lyse. ❖ ♦ Méd. Décroissance d une courbe thermique …   Encyclopédie Universelle

  • -lysis — scientific/medical suffix meaning loosening, dissolving, dissolution, from Gk. lysis a loosening, setting free, releasing, dissolution, from lyein to unfasten, loose, loosen, untie (see LOSE (Cf. lose)) …   Etymology dictionary

  • lysis — lysis. См. лизис. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Lysis [1] — Lysis (gr.), 1) (Med.), die Lösung, die allmälige Genesung; 2) (Bauk.), so v.w. Rinnleiste …   Pierer's Universal-Lexikon

  • Lysis [2] — Lysis, 1) L. aus Athen, Schüler des Sokrates, nach welchem Plato seinen von der Liebe u. Freundschaft handelnden Dialog nannte. 2) L. aus Tarent, Schüler des Pythagoras, ging nach der Auflösung des Bundes nach Theben, wo er im Hause des… …   Pierer's Universal-Lexikon

  • Lysis — (griech.), s. Krisis …   Meyers Großes Konversations-Lexikon

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