Characterization of biological ice nuclei from a lichen.
Biological ice nuclei (active at approximately -4 degrees C) were extracted from cells of the lichen Rhizoplaca chrysoleuca by sonication. Sensitivity to proteases, guanidine hydrochloride, and urea showed these nuclei to be proteinaceous. The nuclei were relatively heat stable, active from pH 1.5 to 12, and active without lipids, thereby demonstrating significant differences from bacterial ice nuclei.
Department of Biology, New Mexico Institute of Mining and Technology, Socorro 87801.
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D001419:Bacteria / Q000032:analysis; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007053:Ice; D008011:Lichens / Q000032:analysis*; D010447:Peptide Hydrolases / Q000494:pharmacology; D013696:Temperature; D014508:Urea / Q000494:pharmacology
D006146:Guanidines; D007053:Ice; D014508:Urea; D010447:Peptide Hydrolases; D019791:Guanidine