The next time you’re at a picnic or backyard barbecue and the host reveals that there’s no more ice to keep the beer cold, you can be a hero by handing over a Petri dish filled with a bacteria that makes its own ice. OK, it has to be a pretty big Petri dish and a lot of bacteria but you want to be a hero, don’t you?
The bacteria is Pseudomonas syringae, a plant-killing pathogen that makes frost even in warm weather to destroy the leaves on crops. Until recently, the way it does this was unexplained but that hasn’t stopped ski resort owners from harvesting the bacteria and using it to make artificial snow. A new report in Science Advances details recent research that has finally unlocked the secret of these icy killers.
Scientists at the Max Planck Institute for Polymer Research in Mainz, Germany, studied the interaction between the bacteria and water molecules using a process called sum frequency generation spectroscopy. This laser technique detected proteins in the cell membrane of Pseudomonas syringae that realign the positioning of water molecules so that they’re in a lattice array as they are in ice. P. syringae then vibrates to remove the heat from the latticed water molecules and the end result is tiny cubes of ice. The bacteria protects itself from freezing in its own ice cooler with other proteins that act as antifreeze.
On a plant, this ice-making process damages leaves and stems, allowing P. syringae to spread many diseases among fruit trees, vegetables and flowers. And spread it does – the bacteria covers the planet and is found in soil as well as in lower parts of the atmosphere. In fact, it uses clouds to spread itself by forming ice crystals which form rain which falls onto plants where the bacteria form ice crystals … you get the idea.
This ability to form rain may one day make P. syringae a hero too – and not just at picnics or ski resorts. The researchers are looking at ways to plant crops that produce a lot of P. syringae and put them in areas that need rain or in locations where wind patterns will pick them up and move them over drought-stricken areas. Sounds like an all-natural cloud-seeding process.
What about the warm beer? Leave the P. syringae to help make rain and just bring an extra bag of ice.