Biogenic antifreeze agent

from Wikipedia, the free encyclopedia

A biogenic anti-freeze is an anti-freeze that has been produced by living things .

properties

Biological antifreeze agents include low molecular weight compounds and anti-freeze proteins . They occur in particular in organisms from arctic climates. Glycerol , other polyols , urea and glucose , among others , are used as low molecular weight compounds . These are compounds that will readily form hydrogen bonds with neighboring water molecules. This lowers the freezing point within the cells , which prevents perforation of the cell membrane by ice crystals. In some cases, the concentration of water in the cells is also reduced ( anhydrobiosis ).

Most anti-freeze proteins do not prevent cell plasma from freezing, but they can delay it a little. Their effect is based on the fact that they hinder the growth of the ice crystals and shield already formed ice crystals, which could act as crystallization nuclei . As a result, the resulting crystals remain small, the ice becomes fine-grained and cannot destroy the structure of the cell even if it freezes through. After thawing, the cell resumes its normal functions.

Cryopreservation

In biochemistry, cells for cryopreservation are usually frozen in a freezing medium from the culture medium with dimethyl sulfoxide , e.g. B. in culture medium with 20% (V / V) FCS and 10% (V / V) DMSO. In some cases, ethylene glycol is also used instead of DMSO . In the case of vitrification , on the other hand, an attempt is made to avoid the formation of ice crystals during cooling entirely B. with concentrated glycerol solutions (17 moles per kilogram).

Individual evidence

  1. Jump up ↑ DJ Larson, L. Middle, H. Vu, W. Zhang, AS Serianni, J. Duman, BM Barnes: Wood frog adaptations to overwintering in Alaska: new limits to freezing tolerance. In: The Journal of experimental biology. Volume 217, Pt 12 June 2014, pp. 2193-2200, doi : 10.1242 / jeb.101931 , PMID 24737762 .
  2. ↑ JP Costanzo, AM Reynolds, MC do Amaral, AJ Rosendale, RE Lee: Cryoprotectants and extreme freeze tolerance in a subarctic population of the wood frog. In: PloS one. Volume 10, number 2, 2015, p. E0117234, doi : 10.1371 / journal.pone.0117234 , PMID 25688861 , PMC 4331536 (free full text).
  3. ↑ Z. Shu, S. Heimfeld, D. Gao: Hematopoietic SCT with cryopreserved grafts: adverse reactions after transplantation and cryoprotectant removal before infusion. In: Bone Marrow Transplant. Volume 49, number 4, April 2014, pp. 469–476, doi : 10.1038 / bmt.2013.152 , PMID 24076548 , PMC 4420483 (free full text).
  4. ↑ Y. Agca, J. Liu, AT Peter, ES Critser, JK Critser: Effect of developmental stage on bovine oocyte plasma membrane water and cryoprotectant permeability characteristics. In: Molecular reproduction and development. Volume 49, Number 4, April 1998, pp. 408-415, doi : 10.1002 / (SICI) 1098-2795 (199804) 49: 4 <408 :: AID-MRD8> 3.0.CO; 2-R , PMID 9508092 .
  5. ↑ JA Bautista, H. Kanagawa: Current status of vitrification of embryos and oocytes in domestic animals: ethylene glycol as an emerging cryoprotectant of choice. In: The Japanese journal of veterinary research. Volume 45, Number 4, February 1998, pp. 183-191, PMID 9553322 .
  6. ^ AF Davidson, C. Glasscock, DR McClanahan, JD Benson, AZ Higgins: Toxicity Minimized Cryoprotectant Addition and Removal Procedures for Adherent Endothelial Cells. In: PloS one. Volume 10, number 11, 2015, p. E0142828, doi : 10.1371 / journal.pone.0142828 , PMID 26605546 , PMC 4659675 (free full text).