Plant thermal hysteresis proteins.
Proteins which produce a thermal hysteresis (i.e. lower the freezing point of water below the melting point) are common antifreezes in cold adapted poikilothermic animals, especially fishes from ice-laden seas and terrestrial arthropods. However, these proteins have not been previously identified in plants. 16 species of plants collected from northern Indiana in autumn and winter had low levels of thermal hysteresis activity, but activity was absent in summer. This suggests that thermal hysteresis proteins may be a fairly common winter adaptation in angiosperms. Winter stem fluid from the bittersweet nightshade, Solanum dulcamara L., also showed the recrystallization inhibition activity characteristic of the animal thermal hysteresis proteins (THPs), suggesting a possible function for the THPs in this freeze tolerant species. Other potential functions are discussed. Antibodies to an insect THP cross reacted on immunoelectroblots with proteins in S. dulcamara stem fluid, indicating common epitopes in the insect and plant THPs.
Urrutia
M E
ME
Department of Biological Sciences, University of Notre Dame, IN 46556.
Duman
J G
JG
Knight
C A
CA
D000064:Acclimatization; D021301:Antifreeze Proteins; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005615:Freezing; D006023:Glycoproteins / Q000302:isolation & purification / Q000502:physiology*; D008970:Molecular Weight; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D013045:Species Specificity
D021301:Antifreeze Proteins; D006023:Glycoproteins; D010940:Plant Proteins