Mic Lecture2

Introduction to Microbiology Department of Applied Science King Saud University/ Community College By: Murad Sawalha

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Outline • Other field of microbiology: - Paleomicrobiology. - Parasitology - Sanitary microbiology - Veterinary microbiology. • Pioneers in the science of microbiology: - Anton Van Leeuwenhoek (1632-1723) - Louis Pasteur (1822-1895) - Robert Koch (1843-1910) • Metric system • Microscopes

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Other field of microbiology • Paleomicrobiology: involves the study of ancient microbes, excellent career field for individuals withh interest in Anthropology, archaeology, & microbiology.

• Parasitology: parasite means any organism that lives in or on another living organism, include all microorganisms in our endogenous flora. - This field involves 3 categories of parasites: parasitic protozoa, helminths, & anthropods.

• Sanitary microbiology: includes the processes & disposal of garbage & sewage wastes, as well as the purification and processing of water supplies.

• Veterinary microbiology: concern of microorganisms cause

infectious diseases in animals, and the transmission of diseases from animals to humans. - Zoonoses or zoonotic diseases: infectious diseases of humans that are acquired from animal 3

Pioneers in the science of microbiology • 1) Anton Van Leeuwenhoek (1632-1723) • Invented the first microscope (50 – 300x), was the first to accurately observe and describe microorganisms.

• The first person who saw live bacteria & protozoa, for that he is referred to •

as the father of microbiology, bacteriology, & protozoology. Was not a trained scientist.

• He used his microscope to examine many specimens, he observed tiny creatures which he called animalcules.

• Record his observations in letters, which convinced scientists of the existance of microorganisms.

• Depend on these findings, abiogenesis theory developed (the idea that life can arise spontaneously from non living material).

• Following the works of Pasteur & Tyndall, this theory disproved, and

proved that life can arise only from preexisting life (theory of biogenesis) 4

Pioneers in the science of microbiology • 2) Louis Pasteur (1822-1895)

• Through his experiments, Pasteur dealt the fatal blow to the theory of spontaneous generation (abiogenesis)

• Developed vaccines for Chickenpox, anthrax, rabies • Demonstrated that all fermentations were due to the activities of specific yeasts and bacteria.

• Developed Pasteurization to preserve wine during storage. • Pasteurization: can be used to kill pathogens in many types of liquids. • Discovered that fermentative microorganisms were anaerobic and could live only in absence of oxygen.

• He made significant contributions to the germ theory of disease (specific microorganisms cause specific infectious diseases), such as anthrax is caused by a specific bacterium “Bacillus anthracis”, & tuberculosis is caused by “Mycobacterium tuberculosis” 5

Pioneers in the science of microbiology 3) Robert Koch (1843-1910)

• 3) Robert Koch (1843-1910)

• Proved that the anthrax bacillus is the cause of anthrax (contribute in the germ theory)

• He discovered that Bacillus anthracis produces spores, capable of resisting adverse conditions.

• He developed methods of fixing, staining, & photographing bacteria

• He developed methods of cultivating bacteria on solid media

- Petri dash: flat glass dish to culture bacteria on solid media - Use of agar (a polysaccharide obtained from seaweed) as a solidifying agent. - Pure culture: means only one type of organism is growing in a solid culture medium 6or

Cont. • Koch’s Postulates: scientific procedure to prove that a specific microorganism is the cause of a specific infectious disease: - Microorganism must be present in every case of the disease but absent from healthy individuals

- The suspected microorganism must be isolated and grown in pure cultures. - The disease must result when the isolated microorganism is inoculated into a healthy host. - The same microorganism must be isolated from the disease host. • Exceptions to Kochs postulates:

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Metric system • Is used to describe the sizes of

microorganisms, the sizes of bacteria and protozoa are expressed in micrometers, whereas the sizes of viruses are expressed in nanometer. • A meter can be divided into 10 decimeters, 100 centimeters, 1000 millimeters, 1 million micrometers, or 1 billion nanometers. 8