JD. 1956. Structure of small viruses. Nature 177:473– 475.
Authors deduce from X-ray crystal analysis of plant virus particles that virus shells (capsids) are composed of a large number of identical protein molecules, of small or moderate size, packed together in a regular manner.
Murray NE, Gann A. 2007. What has phage lambda ever done for us? Curr Biol 17:R305–R312.
The authors describe how study of the bacteriophage lambda has contributed to an understanding of the molecular basis of numerous fundamental biological processes.
Suttle CA. 2007. Marine viruses—major players in the global ecosystem.
Nat Rev Microbiol 5:801–812.
Suttle describes the unappreciated yet enormous contribution that the huge numbers of marine viruses make to the earth’s marine and global ecosystems.
Websites
https://talk.ictvonline.org/taxonomy/ Latest update of virus classification from the ICTV.
http://ictvonline.org/ ICTV-approved virus names and other information as well as links to virus databases can be downloaded.
http://microbe.tv/twiv A weekly podcast about viruses featuring informal yet informative interviews with guest virologists who discuss their recent findings and other topics of general interest.
STUDY QUESTIONS
1 What is the definition of a virus?
2 Which is a key property first discovered about viruses that distinguished them from other microorganisms?They were too large to pass through a 0.2-micron filterThey could reproduce only in brothThey made tobacco plants sickThey were small enough to pass through a 0.2-micron filterNone of the above
3 All of us carry many different viruses throughout our daily lives. Why don’t they make us sick?
4 Why do we care that viruses comprise the most biodiversity on the planet?
5 The first viruses were discovered near the end of the 1800s. How was this done?By transmitting a disease to tobacco plants using a cell-free filtrate of diseased leavesPasteur showed that viruses could reproduce in a sterile mediumLeeuwenhoek saw viruses in his microscopeRobert Koch showed that viruses grown in broth could cause diseaseAll of the above
6 Why were the bacteriophage systems so useful for elucidating principles of viral reproduction? What important features of virus-host interactions were discovered from these studies?
7 How are viruses classified?
8 How does the discovery of new viruses today differ from 100 years ago?
9 Which host cell function is essential for the reproduction of all viruses?
10 What is the basis of the Baltimore classification system? How many genome types are sufficient to describe all viral families in this system?
2 The Infectious Cycle
The Infectious Cycle The Cell Entering Cells Viral RNA Synthesis Viral Protein Synthesis Viral Genome Replication Assembly of Progeny Virus Particles
Cultivation of Viruses Cell Culture Embryonated Eggs Laboratory Animals
Assay of Viruses Measurement of Infectious Units Efficiency of Plating Measurement of Virus Particles
Viral Reproduction: the Burst Concept
The One-Step Growth Cycle One-Step Growth Analysis: a Valuable Tool for Studying Animal Viruses
Global Analysis DNA Microarrays Mass Spectrometry Protein-Protein Interactions
LINKS FOR CHAPTER 2
Video: Interview with Dr. Thomas Hope http://bit.ly/Virology_Hope
Cloning
