A new ice-nucleating bacterium, KUEN-3, was isolated from strawberry leaves. The ice-nucleating bacterium was found in the pale yellow colony group. Strain KUEN-3 was identified as Erwinia uredovora from its taxonomical characteristics. Whenstrain KUEN-3was cultured aerobically in a mediumconsisting of Simmons-citric acid broth (pH 6.1) for 24 hr at 18°C, the ice-nucleating activity of strain KUIN-3cells was obtained. The ice-nucleating temperature, J50 (°C) was detected at-2.8°C in cell suspensions (1.1 x 108cells/ml) of strain KUEN-3.The ice-nucleating temperature was significantly decreased by treating cell suspensions for 30min at 40°C and was completely lost by heating them at 90°C. The plot of ice-nucleating temperature versus treatment temperature (°C) is similar to the curve that was obtained for cell suspensions of another ice-nucleating bacteria. The susceptibility of cell ice nuclei to urea or protein-modifying reagents suggests that proteins participate in the ice-nucleating event.

An ice-nucleating bacterium, strain KUIN-1, was isolated from the leaves of field beans {Phaseolus vulgaris L.). Strain KUIN-1 was identified as Pseudomonas fluorescens from its taxonomical characteristics. Ice-nucleating activity was obtained when strain KUIN-1 was cultured aerobically in a medium containing Koser citrate broth (pH 7.0) for 24hr at 18°C. The icenucleating activity did not appear until the bacterial cell concentration reached 107 to 108/ml.Nucleation at -3.0°C was detected in suspensions (1.8 x 109cells/ml) of cells that had been grown on the mediumcontaining Koser citrate broth. Strain KUIN-1produced a lower nucleation frequency {i.e. the number of ice nuclei/cell) than did ice-nucleating Pseudomonas syringae No. 3 1 suspensions, particularly at temperatures above -5°C. The nucleation frequency of strain KUIN-1-suspensions was similar to that obtained for an ice-nucleating Erwinia herbicola No. 26 at -5°C.

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