PREFACE
We human beings are severely outnumbered by microbes. The average human body contains about ten trillion cells, but has approximately ten times as many microorganisms, or 100 trillion microbes. It is about time you were introduced to these passengers you cart around with you!
Most of the microorganisms that call your body “home” are components of your normal microbiota. If they stay in balance and in the specific location they belong (the correct address as it were), they do us no harm. In fact, many of these organisms provide essential services for you, their host. This normal microbiota is one of our main sources of such necessary substances as niacin, thiamine, riboflavin, folic acid, biotin, and vitamin K. In addition, these resident microbes serve to protect us from invasion by other potentially pathogenic microorganisms. They do this by competing for food, space, and occasionally producing antimicrobial substances such as antibiotics that tend to discourage the arrival of new neighbors.
Microbes also proliferate outside the human body. They are crucial to our survival on this planet as they help maintain the balance of living organisms and chemicals in our ecosystems. Microbes form the basis of the food chain in the oceans and lakes of the world. Some can “fix” nitrogen gas from the air into the form that other organisms may utilize, i.e. organic compounds. Some microbes are photosynthetic, and as such, capture the energy in sunlight for the rest of us to exploit. They are used to produce chemicals such as acetone, alcohols, and many drugs. Microbes are employed by the food industry to produce such items as sauerkraut, cheese, yogurt, bread, etc. These food industry “employees” don’t even demand minimum wage!
Nevertheless, microorganisms can be the cause of human disease, infection, and even death. In our quest to maintain good health, it is essential to understand why the relationship between man and microbe goes awry and how to prevent the process from causing severe damage. Thus, this microbiology laboratory manual will function to initiate you into this world which is quite unfamiliar to most individuals. It is a fascinating discipline which I look forward enthusiastically to sharing with you.
As with most of life’s experiences, you will get out of your microbiology class what you put into it. It is extremely important that you are prepared when performing the labs. Make it a point to always read the exercises you will perform before you begin and watch the videos.