The microbial world is composed of a complex array of life forms, each maintaining the characteristics of life in its own unique way. To develop an understanding of the useful and harmful actions of microbes and apply this knowledge in beneficial ways, a clear and detailed understanding of their structure and function must be developed.
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The extremely small size of these organisms makes this task very difficult and demands special equipment and techniques.
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Since most microbes are too small to be seen with the naked, eye, special microscopes have been developed that produce enlarged, clear images. Viewing specimens through a light microscope provides information on the high percentage of water in cells (70-90 percent) allows visible light rays to pass through the cell very easily and little contrast is developed between the cell and its surroundings.
To overcome this problem and highlight special cell components, dyes or stains are used to colour the cell before viewing. In addition, there are types of microscopes which may be used to obtain other perspectives of microbes. Ultraviolet light microscopes and electron microscopes have advantages not found in standard light microscopes.
The small size of microbes also limits a researcher’s ability to gather information, about a single microbe. Laboratory methods used to study large multicellular organisms such as animals and plants are not readily adapted to the microbiology lab.
An individual microbe is not easily dissected and studied apart from the whole organism. For this reason, microbiologists must approach the study of microbes using different, more effective, techniques.
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Microbes are usually studied in pure culture and studied collectively. Our understanding of species is based on what the “group” does or how it behaves in a particular environment.
If microbes of a different species become mixed with the study group, the results of the study may be inaccurate. Therefore, microbiologists spend much time and energy maintaining pure cultures for study.
Many special procedures have been developed to prevent both contamination of pure cultures and the lab worker by invisible bacteria. The tools and techniques used in microbiology laboratories to investigate the nature of microbes will be described in this chapter, and specific applications will be made wherever possible.