scholarly journals DSC Study on the Thermal Hysteresis Activity of Plant Antifreeze Proteins

2001 ◽  
Vol 17 (01) ◽  
pp. 66-69
Author(s):  
Zhou Xiao-Lei ◽  
◽  
Chen Tao-Tao ◽  
Wang Bao-Huai ◽  
Li Zhi-Fen ◽  
...  
2020 ◽  
Author(s):  
Jinzi Deng ◽  
Elana Apfelbaum ◽  
Ran Drori

<p>Since some antifreeze proteins and glycoproteins (AF(G)Ps) cannot directly bind to all crystal planes, they change ice crystal morphology by minimizing the area of the crystal planes to which they cannot bind until crystal growth is halted. Previous studies found that growth along the <i>c</i>-axis (perpendicular to the basal plane, the crystal plane to which these AF(G)Ps cannot bind) is accelerated by some AF(G)Ps, while growth of other planes is inhibited. The effects of this growth acceleration on crystal morphology and on the thermal hysteresis activity are unknown to date. Understanding these effects will elucidate the mechanism of ice growth inhibition by AF(G)Ps. Using cold stages and an Infrared laser, ice growth velocities and crystal morphologies in AF(G)P solutions were measured. Three types of effects on growth velocity were found: concentration-dependent acceleration, concentration-independent acceleration, and concentration-dependent deceleration. Quantitative crystal morphology measurements in AF(G)P solutions demonstrated that adsorption rate of the proteins to ice plays a major role in determining the morphology of the bipyramidal crystal. These results demonstrate that faster adsorption rates generate bipyramidal crystals with diminished basal surfaces at higher temperatures compared to slower adsorption rates. The acceleration of growth along the <i>c</i>-axis generates crystals with smaller basal surfaces at higher temperatures leading to increased growth inhibition of the entire crystal.<a></a></p>


2010 ◽  
Vol 90 (1) ◽  
pp. 35-40 ◽  
Author(s):  
S. Yu ◽  
L. Yin ◽  
S. Mu

Overwintering plants produce antifreeze proteins (AFPs) that allow plants to survive under freezing or sub-freezing conditions. Ammopiptanthus nanus (M. Pop.) Cheng f. grows in the desert of Xinjiang, P.R. China, and our objective was to determine if its survival was dependent on AFP and to identify the protein. Using anion exchange and gel filtration, the AFP was extracted, isolated and purified from cold-acclimated A. nanus leaves. The thermal hysteresis activity (THA) of the antifreeze proteins was measured by differential scanning calorimetry. The THA of the AFP was 0.46°C when the concentration of the protein was 20 mg mL-1. The molecular weight of a band was about 119.24 kDa in SDS-PAGE gel. We detected (P < 0.05) the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit by analyzing the 119.24 kDa protein using the Waters SYNAPT™ high definition mass spectrometry (HDMS™) System. Our results indicate that there is an AFP in A. nanus leaves, and that it may play a vital role as a defence against the cold climate, thus increasing the chances for survival of A. nanus in its desert habitat.Key words: Thermal hysteresis activity, differential scanning calorimetry, extraction, purification, cold climate, desert habitat


RSC Advances ◽  
2015 ◽  
Vol 5 (11) ◽  
pp. 7848-7853 ◽  
Author(s):  
Ran Drori ◽  
Peter L. Davies ◽  
Ido Braslavsky

Temperature-controlled microfluidic devices and fluorescence microscopy illustrate the correlation between freezing-point depression and the distance between antifreeze proteins on an ice surface.


2020 ◽  
Author(s):  
Jinzi Deng ◽  
Elana Apfelbaum ◽  
Ran Drori

<p>Since some antifreeze proteins and glycoproteins (AF(G)Ps) cannot directly bind to all crystal planes, they change ice crystal morphology by minimizing the area of the crystal planes to which they cannot bind until crystal growth is halted. Previous studies found that growth along the <i>c</i>-axis (perpendicular to the basal plane, the crystal plane to which these AF(G)Ps cannot bind) is accelerated by some AF(G)Ps, while growth of other planes is inhibited. The effects of this growth acceleration on crystal morphology and on the thermal hysteresis activity are unknown to date. Understanding these effects will elucidate the mechanism of ice growth inhibition by AF(G)Ps. Using cold stages and an Infrared laser, ice growth velocities and crystal morphologies in AF(G)P solutions were measured. Three types of effects on growth velocity were found: concentration-dependent acceleration, concentration-independent acceleration, and concentration-dependent deceleration. Quantitative crystal morphology measurements in AF(G)P solutions demonstrated that adsorption rate of the proteins to ice plays a major role in determining the morphology of the bipyramidal crystal. These results demonstrate that faster adsorption rates generate bipyramidal crystals with diminished basal surfaces at higher temperatures compared to slower adsorption rates. The acceleration of growth along the <i>c</i>-axis generates crystals with smaller basal surfaces at higher temperatures leading to increased growth inhibition of the entire crystal.<a></a></p>


2020 ◽  
pp. 189-226
Author(s):  
Michael Wisniewski ◽  
Ian R. Willick ◽  
John G. Duman ◽  
David Livingston ◽  
Samuel S. Newton

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