A New Hope

Help me agar, you are my only hope.

With the efforts of previous weeks directing our methods, week 3 passed very quickly with relative efficiency. This week had a few aims.

  • Using what had already been learnt, experiment with new traps based on different mediums
  • Choose the most effective protein dye
  • Further examine the effects of cercariae penetration on elastase release

With regard to our first criteria we experienced relative success! From previous weeks we had learnt the importance of leaving adequate time for the cercariae to burrow. Wax also did not seem like a good medium and so we experimented with a variety of new chemicals. Initially agar got us all very excited as Adam was clearly able to count several stained cercariae in a trap we had left out for several hours. Agar was key in re-enforcing our beliefs that through the correct combination of chemicals, the parasite could be induced to burrow and become trapped in the solid medium of our trap. The end of this week yielded our most significant discovery, we counted our most cercariae burrowed yet and not in agar, but in a medium consisting of a film-forming polymer dissolved in an organic solvent.

This week we learnt how to make a trap that works. We were still yet to optimise this trap and were still using rather a sporadic array of chemicals to attract our parasite: which although successful was far from efficient. Despite running several repeats we also could not be sure whether agar or our newly discovered chemical made up a better solid medium for our trap. On top of all this we were still yet to determine how successfully we would be able to cross link our traps to a detector agent for experiment plan A.
Our next aim was to choose an effective protein dye. We incorporated stained-elastin tissue into our traps. No physical crosslinking or adhesion was used but the tissue was physically present near the traps. When mixed with parasite-infested water we observed two things: the tissue became fragmented and degraded and the stain seemed to run off into solution. This was compared with a control sample of both trap and tissue added to a solution of mineral water. Visually our results seemed indicative that the presence of cercariae and thus elastase seemed to stimulate stain release and tissue degradation. However we still witnessed stain release in our control sample, was the effect of elastase really important?

Several repeats confirmed it was; readings in the spectrophotometer showed our stain had been eluted significantly more in a solution of cercariae than in a control solution of water.
This effect was observed with all the stains we used, however most potently with the haematoxylin and fuschine samples. Thus we are going to use these two stains from now on.