Welcome to MCB3020L General Microbiology
Welcome to MCB3020L
General Microbiology
Lab
Remote Learning Course
Text resources will be uploaded to Canvas weekly
Grades will be posted to Canvas weekly following labs
Powerpoint created by Danielle Hatt and Robert Tomasetti
Purpose
Purpose: The aim of today’s lab is to determine the host range specificity
of any phages present in a sample: FIU sewage. Phage host specificity will
be tested against 8 bacterial species from 3 broad classes.
Phage titer for each bacterial species will be calculated and phage plaque
formation will be compared for different bacterial species.
Plaques will be transferred from infected lysed areas of one bacterial
species to bacterial cultures of other species to test host range specificity
next lab period.
Why Bacteriophages?
Phages are viruses that infect bacteria and are likely the most abundant
organisms by biomass in the world. Studying plaque formation of phages
allows the calculation of a “phage titer,” which is the same equation used
later in the semester to calculate “viable titer” of bacterial samples.
What are bacteriophages
• Viruses that infect bacteria by injecting DNA/RNA phage
genetic material into bacterial cytoplasm, taking over the
“machinery” of the host and causing replication of phages
• Burst (typically lysing the host cell), usually 100-200 phages
released per host cell
• Unique host range specificity of bacteria (infection
capability)
• Some phages are specific to a single bacterial species or
group of closely-related bacteria. Specific phages will live
wherever their host bacteria live
• A plaque is a clear zone observed due to the lysing of a
bacterial cell.
