Lecture 1 Micro biology.pdf on Lecture #1 Introduction to Microbiology

introduction to university microbiology

1. Lecture #1Introduction to Microbiology
Monday May 6, 2019
Textbook Chapter #1
Thursday September 5, 2019
Monday January 18, 2021

2. What are Microorganisms
•Prokaryotes: Bacteria and Archaea
•Eukaryotes: Protozoa, Fungi
•Viruses: acellular requiring a living
host cell to reproduce
Prokaryotes Archaea Eukaryotes
-Lack a
membrane bound
nucleus
-Single circular
chromosome
-Able to live in adverse
environmental
conditions (high salt
concentrations, high
temperatures and acidic
environments)
-Contain a membrane bound
nucleus and membrane
bound organelles
-Protozoa and fungi are
microbes within this group

3. Naming of Microorganisms
•Binomial System of Nomenclature:
•Genus name followed by a Species name
Example: Staphylococcus aureus
•Many species often exist within a genus
Example:the Bacteroides genus contains greater than 100 species
•The genus and species of the bacterium must be italicized or
underlined
•The name of the bacterium may also written with the first letter of the
Genus (capitalized) and the name of the species (not capitalized)
•Example:S.aureus

5. Why is Microbiology Important
•Microorganisms are very important to many areas of human, animal,
and plant life
•Gave way to the introduction and development of higher life forms
(atmospheric oxygen was likely produced by primitive photosynthetic
microbes)
•Important to degrade organic material and for atmospheric nitrogen fixation in
plants
•Microorganisms produce antibiotics that are used in clinical practice
•Normal bacteria within the human body prevent the growth of harmful
bacteria
•Used for fermentation in the food industry (beer, wine, yogurt)

6. Historical Timeline of Microbiology
•1665: Robert Hooke is the first to see and describe cells following the
invention of the microscope which led to the start of the cell theory
(all living things are composed of cells)
•1684: Anthonivan Leeuwenhoek used the microscope to view live
microbes which he called animalcules

7. Spontaneous Generation
vs
Biogenesis
Spontaneous Generation:
-Food left for long periods of time will eventually spoil
-Microscopic examination reveals that the spoiled
food is crawling with bacteria
-This theory notes that these bacteria arise
spontaneously from non-living matter
-Louis Pasteur rejected this theory
Biogenesis:
-The hypothesis that living matter
arises only from pre-existing living
matter
-It is this theory that is currently
accepted

8. Historical Timeline of Microbiology
•1864: Louis Pasteur demonstrated aseptic technique using a swan neck
flask
•Hypothesized that microorganisms responsible for food spoilage likely came
from the air and not from spontaneous generation
•The results of this experiment demonstrated that spontaneous generation
could not occur

9. Other Contributions Pasteur Made to the
Understanding of Microbiology
•It was first thought that air converted sugar into alcohol
•Pasteur showed that it is yeast that which convert sugar to alcohol in
the absence of air using a process called Fermentation
•He determined that you could prevent the souring of milk and
beer/wine which occurs when the bacteria present convert sugar into
vinegar you could heat the milk/beer/wine which would kill all of the
bacteria present and prevent spoilage
•This procedure is still used today and is called Pasteurization

10. Historical Timeline of Microbiology Continued
•1881: Germ Theory of Disease-
This is the belief that
microorganisms are responsible for
disease
•This theory was developed by
Robert Koch on the basis that
microbes alter the chemical and
physical nature of organic material
•This led to the development of
Kochs Postulates which are used
today in order to prove that a
specific microbe is responsible for a
specific disease

11. Historical Timeline of Microbiology Continued
•1798: Edward Jenner-developed the small pox vaccine
•Based on the observation that people previously infected with cow pox were
immune to small pox
•He injected a young boy with cow pox and the boy became mildly ill
•It was later discovered that this boy was immune to small pox

12. •1908: Paul Ehrlich-developed the idea of selective toxicity
•Selective Toxicity: The ability to either kill or inhibit the growth of
pathogenic organisms while leaving the host unharmed
•He discovered the first effective anti-microbial Salvarsan which was
useful to cure syphilis without damaging host cells
Historical Timeline of Microbiology Continued

13. •1929: Alexander Fleming
•Discovered that a product of the mold Penicillium chrysogenumwas able to
inhibit the growth of bacteria on plates contaminated with the mold
•This product was Penicillin
•This discovery was made by accident but consequently revolutionized
modern medicine
Historical Timeline of Microbiology Continued