Download Reading Guide for Week 3

Reading Guide for Week 3 – Bio260
Colleen Sheridan
Stage 02 – Colonization and Infection
Unfortunately, some bacteria managed to make it into our host’s body before we were able to take steps to
reduce disease transmission. In this unit you will be trying to figure out how bacteria adhere to the host’s cells
and grow to colonize the host.
In this week’s reading you will learn about:
1. The principles of infectious disease and Koch’s postulates.
2. How bacterial cellular structures and products lead to colonization and infection.
3. The environmental conditions and ways of measuring prokaryotic cell growth.
Chapter 16: Host-Microbe Interactions (16.3-16.5)
1. What is the difference between colonization and infection?
2. What is the difference between subclinical and infectious disease? What are signs and symptoms?
3. What is the difference between a primary infection and a secondary infection?
4. What is the difference between a primary pathogen and an opportunistic pathogen?
5. What is virulence? What are virulence factors? We will continue to develop this key concept in Stage 03 of
our disease progression timeline when we study immunity and pathogenesis, but start to get a handle on it now.
6. Be able to describe the characteristics of infectious disease such as the infectious dose, the course of disease,
the duration of symptoms, and the distribution of the pathogen.
7. Be able to list Koch’s postulates and understand its importance in establishing the germ theory of disease.
8. Again, in your understanding of what virulence means, understand that Molecular Koch’s postulates allow us
to determine specific microbial genes (or their protein products) that are responsible for the virulence, or how
much disease is produced, of the microbe.
9. Be able to discuss what “distinguishes pathogens from other microbes,” and the four general mechanisms of
pathogenesis. What makes “a successful pathogen”? p. 385
10. Does adherence alone determine whether a microbe will cause disease? Why?
11. Be able to describe the “requirements of adherence and colonization,” and the importance of cellular
structures for this to happen. Brain teaser: Why is iron so important?
12. Understand how another Gram-negative cellular structure, the type III secretion system, can help to
establish microbial infection.
Chapter 4: Dynamics of Prokaryotic Growth (4.1-4.8)
1. Understand what is meant by generation time and binary fission. Do all organisms have the same generation
time? Be able to use the formula on p. 83 to calculate the number of cells in a population after a given
amount of time.
2. Be able to recognize a bacterial growth curve and identify the phases of growth.
Which growth phase is best used for experimentation and why? When are primary metabolites produced?
Secondary metabolites?
3. What is a biofilm? What are some medical applications/examples of biofilms? Are all biofilms damaging?
Remember on page 386 when they referred to bioflims?
4. What is the definition of a pure culture? What are some techniques used to determine if a sample is pure?
How are stock cultures maintained?
5. Explain how physical conditions such as temperature, pH, and oxygen can influence bacterial growth.
6. What is the optimum temperature for growth of psychrophiles, psychrotrophs, mesophiles, and
thermophiles?
7. Know the oxygen requirements for obligate aerobes, facultative aerobes, obligate anaerobes,
microaerophiles, and aerotolerant anaerobes.
What are reactive oxygen species and when are they formed? What do superoxide dismutase and catalase
do?
7. What are the basic chemical requirements for bacterial growth (Table 4.4)? What
does it mean for an organism to be “fastidious”?
8. Know the definitions of the following terms: photoautotroph. photoheterotroph,
chemolithoautotroph, and chemoorganoheterotroph
9. What is the difference between chemically defined media and complex media?
10. What are selective media? What are differential media? Know some examples of each.
11. Describe the following methods to determine the number of bacteria
-Direct cell counts
-Viable Cell Counts
-Measuring Biomass
-Detecting Cell Products
Which methods measure living cells and which measures both living and dead cells?