Sensitivity of partially purified ice nucleation activity of Fusarium acuminatum SRSF 616.
Factors that affect bacterial ice nucleation, including growth medium, growth phase, nutrient deprivation, and cold-temperature exposure, were investigated in the ice nucleation active (INA) fungus Fusarium acuminatum SRSF 616. Ice nucleation activity remained relatively constant throughout the growth cycle, and the cell-free culture supernatant consistently displayed higher ice nucleation activity than the hyphal pellet. Although nutrient starvation and low-temperature exposure enhance bacterial ice nucleation activity, reducing the concentration of C, N, or P in synthetischer nährstoffarmer broth (SNB) did not increase fungal ice nucleation activity, nor did exposure to 4 degrees C or 15 degrees C. From the SNB supernatant, selected INA chromatography fractions were obtained that demonstrated increased sensitivity to proteinase K and heat compared with culture supernatant. We propose that partial purification of the fungal ice nuclei resulted in removal of low-molecular-weight stabilizing factors.
Humphreys
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TL
Department of Microbiology, Miami University, Oxford, OH 45056, USA.
Castrillo
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LA
Lee
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MR
D003470:Culture Media; D005615:Freezing; D005656:Fungal Proteins / Q000302:isolation & purification* / Q000378:metabolism*; D005670:Fusarium / Q000254:growth & development*; D007053:Ice; D013696:Temperature
D003470:Culture Media; D005656:Fungal Proteins; D007053:Ice