Day: February 11, 2007

Tonight’s post will be an eclectic one…

I made the mistake today of heading for what passes for a “large city” in my local area in a general need to go somewhere besides my house and the college. I figured I could browse the local discount bookstore and see if they had anything interesting.

I happened to notice a sign advertising a book sale at the local library.

Why did they have to do this to me? Have they no decency? Have they no shame? Have they no MERCY?

As I previously mentioned, I actually do collect old science (and medical) books. Unfortunately, I ended up walking out of the library with a whole mess of microbiology books (and one Botany book that I picked up just because it was old – 1930’s). Fortunately, they were cheap.
I was just perusing one of the books I picked up: an old “Bacteriology” book[1] from the late 1940’s. It’s fascinating and instructive to see what scientists used to believe was true and what observations led them to believe it.

The introductory chapters of the book include a discussion of taxonomy and the place of “Schizomycetes” (meaning bacteria that aren’t photosynthetic) in the overall scheme of things. There’s a discussion that, given what information was available at the time, is perfectly reasonable and explains why bacteria are “plants”, just like other fungi (Fungi, you see, are just plants that aren’t photosynthetic – or so they explain). The author gives a classification scheme for plants that divide them into three categories, which roughly equate to “normal” plants (with stems and leaves), moss-type plants, and plants that don’t have roots, leaves, stems, or flowers. This latter category he broke into two sub-categories – Algae (including “Blue-green” algae, which we now know are actually bacteria) and Fungi. “Bacteria” are listed as one of the categories of Fungi.

The discussion justifying this categorization makes some interesting claims – some of which are startling to me. The author claims that some bacteria – “Acetobacter xylinum” have cell-walls that consist of cellulose, just like plants. (Actually, it would appear this bacterium does make cellulose, though I don’t think it’s actually a component of the cell wall – this is a standard “Gram-negative” type ?-proteobacterium). I had no idea up to this point that there were cellulose-producing bacteria. Interestingly, the author also states

“Some bacteria are said to possess cell walls of chitin, a distinctly animal substance which is the material of horn, hair, hoof, and insect shell”

which is completely wrong on every count except for the part about insect shells. (Horn, hair, and hoof (and fingernail) material is Keratin, which is a type of tough protein. Chitin is actually a polysaccharide…and it is what most fungal cell walls are made of.There are some interesting statements in the section on microscopy as well. The author claims:

“There seems no doubt that the gram-positive material in bacteria is ribonucleic acid. Bartholomew and Umbreit[2] have shown that it can be removed by soaking the gram-positive cells in sodium choleate. It may be replaced by treating them with magnesium ribonucleate. Normally gram-negative species will not accept the applied coating. The specificity of these reactions is shown by the fact that an enzyme, ribonuclease, will remove the gram-positive character (ribonucleic acid) of the cells very quickly.”

What the heck?… Now I have an urge to see if I can sneak a culture of some kind of Bacillus and some RNAse and see how much of this explanation actually matches observation. (Perhaps I can dig up Bartholomew and Umbreit’s paper as well). The author also mentions that nobody has managed to get a good image of a bacterial nucleus, either, which of course is because they don’t actually have one…
One other thing I’d never heard of: Proton Microscopy. According to the author, this technique, apparently first implemented in France in 1948, could theoretically give substantially better resolution than electron microscopy.

Some quick poking around seems to show that this is partly true, and there actually are proton microscopes that get used for some kinds of studies. However, protons are a heck of a lot harder to “focus” and they don’t seem to have caught on for microbiological work. They do evidently have some useful properties for doing analysis of what specific elements are in a sample, though[3].

I noticed some other apparent differences in style between the older textbooks and current ones, but I’ll save that for another time.

I will also at some point go back and re-write the Schizomycete article to include some of the information I’ve picked up in the last couple of weeks. Meanwhile – one more day of “Just Science” week! Looks like I should survive it after all.