A mouth ulcer made me curious


I am Hardi Parmar, a summer visiting student with TIFR Hyderabad’s science education and outreach program (microcosmos link). That’s how I got my new foldscope.

My first bright idea for the foldscope was kindled by the burning sensation of an ulcer in my mouth. The ulcer must have lots of bacteria I thought, and got curious to see some. I rubbed my finger on the ulcer and its surrounding region. I suppose my fingers were fairly clean, so more stuff got transferred from the ulcer to my finger than the other way around.

Anyway, I spread the dripping liquid on a glass slide.This is how the white part of the liquid looked. I guessed it could be pus from the ulcer.

Picture 1: White stuff around my mouth ulcer

The ulcer itself was whitish. From the internet I found out that it may contain dead cells and food debris.

Three days later my ulcer had healed. During this time the stuff on the slide had mostly dried up, but a few tiny patches of saliva remained under the cover slip (which I had sealed with cello tape). Through the foldscope I looked at these patches.

Picture 2: Edge of cello tape with drops of saliva after 3 days
Picure 3: Patch of saliva remaining after evaporation

Next are two pictures of the dried-up part. I am not sure if I see cells, or the beginnings of bacterial colonies, or something else. A biologist told me told me that the outlines of these shapes are too smooth and rounded for them to be cheek cells. (See more such shapes at the end of this post.)

Picture 4: Dried-up saliva in LED light
Picture 5: Dried-up saliva in sunlight

The bluish pictures are taken with LED light and the grey ones in sunlight.

I also got to see some other things, like..


These may be what they call irregular or filamentous bacterial colonies.

On the internet I also found this amazing visualisation of communities of mouth bacteria.

A few days later I took a sample of my cheek cells. Here is a video of the sample:

Video 1: My cheek cells

The cheek cells are irregular in shape. A couple of smooth oval shapes are also seen, at 7 seconds and 15-18 seconds.They look very much like the shapes that I saw in the previous sample after drying (Pictures 4 and 5). I wonder if they are cells or not.

Picture 9: Oval shape cell with cheek cell

There seem to be some tiny moving things around the cells. Perhaps they are motile bacteria?

– Hardi Parmar

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