Team:Wageningen UR/ecoli survival
The final BeeT product will be applied using sugar water which is transported into the hive by worker bees. This means that our chassis needs to be able to survive in a high sucrose, low (non-carbonic) nutrient environment. In order to test this we looked into whether or not any bacteria would survive such an environment over various time steps. The result of this was that our chassis bacteria, Escherichia coli , was able to grow to at least an entire day in the sugar water. This result shows us that the bees will have at least 24 hours to pick up some of our BeeT. Assuming of course the addition of the various sub systems we have in mind doesn't affect the survival time. The modeling results from the metabolic modeling project only showed what would happen in the time period of 90 seconds to 90 minutes after being put in the sugar water. Because of this, more evidence was needed to see what would happen to the E. coli in the sugar water, for the time scales we were interested in. We know the presence of the high amount of sugar water leads to osmotic pressure. This is because the sucrose molecules from the medium are not able to travel across the cell-membrane, but they still pull the water molecules present inside the cell towards them. The effects of the osmotic pressure on the bacterium were not clear outside of the 90 minute range determined by the metabolic model. However, as determined by the BEEHAVE model, we require that the BeeT survives for days in the sugar water. In this project we aimed to experimentally determine how long BeeT can survive in osmotically unfavourable conditions. The method used to test the survival of E. coli in sugar water experiment is a simple growth experiment. First the bacteria grow overnight to saturate an LB solution. Then a small amount of this is pipetted into various concentrations of sterile sugar water made of high amounts of sucrose and sterilized tap water. After this they are left there for various time steps and then put into sterile LB medium and left to grow overnight. The protocol can be found here The results from the experiments was a great success, as you can see here .
All three experiments clearly show that sugar water is not as lethal as first hypothesized. Not only that, but the results fit with the model in that survival is indeed possible. While the model only shows the effect water efflux of the cell can have on the E. coli, for the range between 90 seconds and 90 minutes. Thus we have shown that E. coli can indeed be used as a chassis for our BeeT. This result was taken into account in the BEEHAVE model.
Introduction
Background
Methods
Results
