SURFACE-PROPERTIES AND SIZE OF THE ICE NUCLEATION SITE IN ICE NUCLEATION ACTIVE BACTERIA - THEORETICAL CONSIDERATIONS

Using heterogeneous ice nucleation theory, the ice nucleation probabilities for various surface properties, shapes, and sizes of heterogeneous nucleator particles have been calculated. These have been compared with experimentally measured sizes of the bacterial ice nucleators of Pseudomonas syringae and related ice nucleation active bacteria. Good fit was obtained for spherical, disk, and cylindrical ice-nucleator particles with ice-nucleator surface tension identical to that of ice. That is to say that the ice-nucleator surface mimics the surface of an ice particle of the same size and shape. The nucleation temperature was predicted to be dependent on the ice-nucleator surface area and volume. To move the nucleation temperature 1 °C higher, the ice-nucleator volume had to be enlarged by 1.3 fold at -13 °C and by 3.5 fold at -3 °C. On the basis of the predicted ice-like surface properties of the ice-nucleator, a mechanism is suggested for the aggregation of the ice-nucleator protein. © 1990.