Moss upclose – and a wriggling surprise

Nov 20, 2014 • 7:01 AM UTC

South Beach, San Francisco, CA, USA

140x Magnification

Microorganisms

Manu Prakash

I am a faculty at Stanford and run the Prakash Lab at Department of Bioengineering at Stanford University. Foldscope community is at the heart of our Frugal Science movement - and I can not tell you how proud I am of this community and grassroots movement. Find our work here: http://prakashlab.stanford.edu

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Summary: I started looking at moss – since it is ultra thin and you get to see through it. I was up for quiet a wriggling squirming surprise.
Green is my favorite color. If I could, I would drive a moss covered car (is that legal?) so it was obvious that I would pluck some moss; and mount it in Foldscope. I was up for quiet a big surprise.
Method:

1. I plucked a little bit of moss. It came with some dirt as well. I don’t know how to identify it; so if you know – please leave a comment. I squished it between the transparent tape to make a Foldscope slide.

2. That’s it. With moss, not much of a methods section. I am assuming I will get great contrast from the chloroplast (green) and from the cell wall.
Results and observations :
1. Firstly, the moss “leaves” are ultra-thin. That is a music to the ears of a microscopist. This way we can actually see the details very well as light passes through the thin sections easily.
Sample prep tip: It’s easy to make a thick sample into a thin sample. Usually simply tearing it leads to layers of cellular material separating, usually close to the edge of the tear. This is a handy trick when looking at plant leaves.

2. Above, the cell wall and the chloroplast is perfectly visible. It’s easy to see that the thin leaves are bent very easily by water surface tension. This results in a droplet trapped in moss; which provides the characteristic reflection you see on wet moss (I will try to get a video of surface tension bending thee moss – a phenomena that has been only recently studied and termed as “elastocapillarity” – balance of elastic and capillary forces).
3. Now for a surprise – this is why doing microscopy in the field teaches you so much. I was panning around when I noticed an almost transparent object pass through my field of view. I looked closely and I found a nematode crawling around – completely transparent – and fairly long. Now, I know this from other places – that people have long debated where nematodes are actually commonly found (in my mind – they are found everywhere); but the fact that it was living inside the moss is valuable.
Watch the video here:
https://vine.co/v/OJvOAA7z3ZI
Next steps:
I wanted to isolate the worm and look at it individually without the moss background. But I had to run; apparently I had been sitting in the garden too long. Don’t you worry my work friend, I will return and uncover you again..