This is an electron microscope, an old version. I was an electron microscopist for about five years at the medical school as well as teaching microbiology to medical and dental students. But this is a giant guy. They've got much more compact versions now. Sometimes you'll see this on T.V. They'll show it to you like this with some people hanging over the scope. It's absolutely fraudulent, Hollywood all over. In order to view specimens, it has to be a darkened room because you're looking at fluorescence off the screen right here. You look through there. All of you are familiar with the regular compound microscope. This is like the compound microscope upside down. So that the electrons come through top, and shoot through the sample. Actually, the condenser is here, over the sample area. The sample is right here, put in by this little knob. See the size of that little red dot (using the laser pointer) that I'm jiggling on the scope there. That's about the size of the sample. This whole chamber of the scope is under high vacuum. It goes through magnifications. The flow of electrons is controlled by magnets here. They are imaged on the round screen that can be seen through the small window near the console surface here.

Now I'm going to show you some EM's (electron micrographs). I'm going to go quickly through this. This is again, E. coli. Remember how I said the cell is jam packed with ribosomes? All of this, little dots in there, that's all ribosomes. The light areas are the nuclear regions. This happens to be a Gram negative so it's got the outer membrane. You can see it's starting to separate over here a little bit. That's an older cell. That's a cross section. This is kind of like an oblong section, like cutting along hot dog. If you cut the hot dog right through, that's the way it looks. You're getting a radial section there. Now, after a quarter hour exposure to ampicillin, look at this guy blowing his guts out over here. You can see a DNA, a nuclear region here. There is another one. You can see how this one hasn't separated yet. If we had cell exposed to a cephalosporin, this would continue to elongate. That's the way a cephalosporin type compound early on would look. It would be very long but you would see these nuclear regions if we were able to stain them. There is one cell. There is another. You could probably count five or six nuclear regions. That was after a quarter hour. After one hour, holy mackerel, everything is dead here. These are all ghost cells. But again, if you're interested in looking at membranes, it really gives you clean membranes all over the place.

Narrative Index

Table of Contents

BioForum Index

AE Partners Collection Index

Activities Exchange Index