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Small and deceptively simple, procaryotes are among nature's
most abundant and ubiquitous microorganisms. If it were somehow
possible to eradicate all bacteria in the world, humans
would notice the effects immediately and, for a while, might find it a favorable
change. We would not have to be as careful about preparing
and refrigerating foods; plaque would no longer develop on our teeth;
and there would be fewer cleaning chores around the house. Quite
suddenly, the medical community's goal of eradicating certain infectious
diseases, such as tuberculosis, cholera, and tetanus, could be a
reality. But there are other considerations to take into account. We
would also have to do without certain foods, like sauerkraut, yogurt,
Swiss cheese, and sourdough bread. At first, this may seem a small
price to pay, but are these slight inconveniences the only sacrifices to
be expected? Within a few days, industrial processes that produce vitamins,
drugs, and solvents would lie abandoned, and most molecular
biology research labs and biotechnology companies would be shut
down. In a few months and years, humus containing dead animal and
plant matter would build up and trap the very elements needed to sustain
the living world. Clearly, bacteria play vital roles in all aspects of our
existence. We literally can't live without them!
In order to explore the roles of bacteria in nutrition, genetics,
drug therapy, infection, and microbial ecology, we must first understand
several aspects of the structure and behavior of procaryotic
cells. The primary topics to be covered in this chapter are elements of
microscopic anatomy, physiology, identification, and classification and
a survey of selected bacterial groups.
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