Fun with light microscopes

Composite image of bovine endothelial cells created with fluorescense microscopy.

I spent three days last week participating in a microscopy workshop organized through a microbial sciences initiative at my school. It was interesting to meet others who different aspect of the micro-world. While I work with specific types of environmental samples, most microbiologists work on a specific model organism trying to figure out a specific process or part of that organism's physiology. Microscopy provided a common tool of interest to all of us!

This is an image of filamentous algae taken out of a Winogradsky Column, which is a great way to grow a lot of bacteria and other microbes in one location with very little work. We looked at many samples (compost, fungi, cultured organisms) under light microscopes but this sample was the most interesting to me to me because it was easy to find lots of cool microbes to take pictures of.

This is another image from the same sample. Here there are at least two different types of organisms, but I don't know what they are. The green is an alga of some sort, and the red could be a colony of purple sulfur bacteria.

After playing around with the basics of light microscopes and trying to perfect our focus, we tried our hand at fluorescence microscopy. This technique uses specific wavelengths of light to excite certain molecules within cells that emit light when they are excited. It is typically used for looking at samples that have been pre-stained with fluorescent dye (like the one at the very beginning of this post), but many of the organisms in the Winogradsky were auto-fluorescent so we were able to get some cool images by looking at them under specific colors of light. This green image is the same image as the one above, but with the red filter on. The organisms absorb red light, and reemit green light.

I looked at this exact part of the sample under red, green, and blue light. Each light excited different organisms, or different parts of the same organism. When you capture an image of each and merge the image you get something pretty cool!

Here is another example, but this time looking at a filamentous algae (shown in red) and a round one (shown in blue).

Stay tuned for even more exciting images from a Scanning Electron Microscope (SEM)!