Microbes

Microbe Hunters- Book Review

De Kruif, Paul. (1926). Microbe Hunters. Orlando, FL: Harcourt, Inc.

First published in 1926, Microbe Hunters follows the many adventures of the first scientists to discover and study microorganisms. Paul de Kruif starts off with Leeuwenhoek (1632-1723), who biology students would recognize as a major contributor to the improvement of the microscope, and ends with Paul Ehrlich, a German physician and scientist who lived from 1854-1915.

What makes this book so fun to read is how de Kruif brings the personalities of the scientists to life. Here are some examples:

1. The Royal Society dispatched a representative to go and ask Leeuwenhoek about his instruments. The representative offered money to buy a microscope to which Leeuwenhoek exclaimed, “No!” The representative pressed further by saying, “But your instruments are marvelous! A thousand times more clear they show things than any lens we have in England.” Leeuwenhoek simply responded, “How I wish, Sir, that I could show you my best lens, with my special way of observing, but I keep that only for myself and do not show it to any one– not even to my own family.”

2. At the end of one of his experiments, Spallanzani exclaimed, “I have discovered a great new fact: living things exist that can stand boiling water and still live– you have to heat them to boiling almost an hour to kill them!”

3. After Pasteur’s swam neck flask experiment, he shouted, “Never will the doctrine of spontaneous generation recover from the mortal blow that this simple experiment has dealt it.”

4. Robert Koch had observed Bacillus anthracis transform its shape into beads. After a month, the beads were still there. After he took some fluid from the eye of an ox and dropped in onto the beaded bacteria, Koch observed, “Those queer shiny beads have turned back into ordinary anthrax bacilli again. The beads must be the spores of the microbe– the tough form of them that can stand great heat, and cold, and drying…THat must be the way the anthrax microbe can keep itself alive in the fields for so long– the bacilli must turn into spores…”

5. Koch confessed to Dr. Rudolph Virchow that he had discovered a way to grow microbes pure and unmixed from other germs. When Virchow asked how, Koch explained, “By growing them on solid food– I can get beautiful isolated colonies of one kind of microbe on the surface of a boiled potato…And now I have invented a better way than that…I mix gelatin with beef broth…and the gelatin sets and makes a solid surface” (does this sound familiar, micro students?).

This book is great. Read it and have fun with it. It’s described this way:

Paul de Kruif’s Microbe Hunters is a timeless dramatization of the scientists, bacteriologists, doctors, and medical technicians who discovered microbes and invented the vaccines to counter them. De Kruif reveals the now seemingly simple but really fundamental discoveries of science—for instance, how a microbe was first viewed in a clear drop of rain water, and when, for the first time ever, Louis Pasteur discovered that a simple vaccine could save a man from the ravages of rabies by attacking the microbes that cause it.

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Team Building: Symbiosis between Termites and Microbes

Microorganisms subsist in the guts of some insects and help with the breakdown of cellulose and lignin and with nitrogen fixation. These particular insects and microorganisms developed a need for each other somewhere along evolutionary lineages, and now they actually benefit from each other in symbiotic relationships. Termites are one example of insects with protists, fungi, and bacteria living in their hindgut. Because termites diverged from cockroaches about 250 million years ago, exploring the similarities and differences of these two insects helps shed light on the evolution of microbial communities in their hindguts and the state of symbiosis in which they exist.

First, it is necessary to understand the digestion of these insects. Termites and cockroaches contribute to the degradation of wood because they have the ability to digest cellulose, a complex carbohydrate that makes up the cell walls of plants and is therefore the major component of wood. The diet of termites is usually high in cellulose because their food is mainly woody material. Cellulose is the most abundant form of carbon on Earth, excluding fossils (Martin, Jones, and Bernays 1991). Termites digest cellulose more efficiently than any other animal, and most animals are not able to digest this bountiful resource. Martin, Jones, and Bernays propose four ways that cellulose is digested in termites.

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