Detecting Viruses: What Are They And How Do We Know When They Are Present?
Keith Perry

Viruses are ever present, affecting most all organisms, from the smallest of bacteria to the most complex of plants and animals. They can be viewed as the simplest of life forms, streamlined as a package of genetic material surrounded by a protein coat. Though viruses are best known for the diseases they cause, many infections may go unnoticed and are not associated with apparent disease. Viruses are usually only ‘seen’ when there is a disease and investigators are prompted to look for them. This exploration will examine what viruses are and the laboratory or diagnostic methods by which they are detected.

Plant viruses are the focus of my research. When a plant is diseased and a virus is suspected as causing the disease, there are two primary approaches to investigation. The first is to establish that there is a transmissible disease agent. We will inoculate healthy plants and observe the appearance of disease symptoms. The second approach is to ‘see’ the virus itself, either by: i) using a biochemical or diagnostic test to determine the presence of the genetic material or the protein coat, or ii) directly observing virus particles in an electron microscope. We will perform two diagnostic tests using antibodies to detect the presence of the virus. We will also look at microscopic and computer generated images that illustrate the diversity of virus particles. You will be asked to return to evaluate responses in your inoculated plants at some point approximately two weeks after the session, and to email your observations to the instructor. Both the return visit and an email with comments are required to receive credit.