The winter winds are blowing. These cold winds whip bacteria up into the atmosphere. These tiny specks of life, unaware of the vast sphere turning beneath them, feel only the cold.
And one particular species of bacterium does something quite special. This bacterium is known as Pseudomonas syringae.
Usually, this unassuming life form lives in plants. It has a number of strategies to attack its plant host, to break apart the cells of a plant to release the delicious nutrients within. Usually, this involves a number of virulence factors, lethal proteins which it injects into the cells. But as winter sets in, this becomes more difficult. The bacterium begins to freeze. But this bacterium still has a trick up it's metaphorical sleeve.
It uses winter as a weapon. As winter sets in, it produces special proteins. These proteins allow ice to form around them, such that they grow out like daggers. These pierce into it's host, ensuring that there will be a nutrient rich bounty waiting for the bacterium when the thaw comes.
But occasionally, a strong wind will blow the bacterium away. And as the bacterium gets higher in the atmosphere, it senses the chill. And, just as it would on a plant, it produces nucleation proteins. Ice crystals begin to form around it. It becomes encased in the heart of a snowflake, and returns to earth.
