Fall 2015 Week 4

Lab has been so productive this week!

On Thursday (9/24/2015) I ran an experiment using the alcohol sterilization method I've been working with all summer on silver leaved nightshade leaves (S. elaeagnifolium). Four days later I knew there was a problem. On Monday I came back to lab and noticed that quadrants A-D all had 1-2 cm sized green, hilly fungal colonies growing on them, which is far too rapid of growth for endophytes.  Quadrant H also had a fungi growing on it that appeared similar to the one that digested my dead grasshopper. All the fungi were growing directly on the leaf suggesting it wasn't contamination introduced because of me but living on the surface of the plant. Based on the physical characteristics of these fungi, I believe they are species I've grown before.

I decided I needed to take a look at my chosen sterilant, 100% ethyl alcohol. When I asked Cori she said that, contrary to assumption, alcohol is a disinfectant not a sterilant, and even then it actually works better with a little water. Thus 70% alcohol is a better disinfectant than 100%. Clearly this isn't going to work the way I thought. I went back to the literature and decided to use bleach again, in the same manner as most current research. Last semester I had a problem with 1.25% bleach killing everything, including potential endophytes, so to find a concentration to work with in the future, I decided to make multiple strength bleach solutions and test which concentration would surface sterilize without penetrating the interior of the leaf. I await conclusive results but nothing has grown on any plates yet, a good sign.

I need to take more photos of my plates so I can remember what these fungi look like, even if they are contaminates. If I remember correctly the microscope photos I took were of spores from green contaminates I grew over the summer.

I made some photos of my plates. This is what I keep growing that looks like contamination:

This is what looks like the same thing that ate the grasshopper: It has the same black spores that bunch in heads and white mycelium.