Humans respond to extreme shock with a strong rush of adrenaline. This response helps survival (at least in some cases). How do bacteria respond to extreme shock? These results come from a study that I have been working on with several colleagues. Using heat as one of the most extreme forms of shock, from 32°C to 42° in a space of several seconds, we found that bacteria have their own distinct form of stress response. From their DNA, they transcribed massive amounts of RNA in just several minutes. The swiftness of the response is similar to the adrenaline of humans. But why the huge amounts of RNA? Even more surpisingly, the vast majority of the RNA does not get translated into protein during the heat shock. So we actually don’t know why the bacteria do this. Our best guess is that the RNA response is the bacteria’s way of getting ready for changes that might follow the heat shock. Having the RNA ready on hand is a good way to save time if, after the heat stress has been removed, conditions allow resumed growth. Those bacteria that can resume growth quickly have a better chance than the slow responders. The important information to take from this study is that the transcription of a gene (from DNA to RNA) is not always followed by translation (from RNA to protein). Rather, both transcription and translation appear to be separately controlled steps, at least for many genes if not all. This is especially significant when one considers that the biology text books like to emphasize a major difference between bacteria and eukaryotes is that transcription and translation are supposed to be coupled processes in bacteria, but not in eukaryotes.
Our study shows that under extreme shock, the bacteria response is not coupled. Such information is useful to know when designing bacteria to be superproducers of PHB. When the peer-review process is completed, I’ll provide a link to the publication.