The Virtual Bacterial Identification Laboratory

 

 

 

Enter the Lab

 

Virtual Bacterial Identification Introduction
Welcome to the Virtual Bacterial Identification Lab. The purpose of the lab is to familiarize you with the science and techniques used to identify different types of bacteria based on their DNA sequence. Not long ago, DNA sequencing was a time-consuming, tedious process. With readily available commercial equipment and kits, it is now routine. The techniques used in this lab are applicable in a wide variety of settings, including scientific research and forensic labs.

Basic Steps

  • Prepare a sample from a patient and isolate whole bacterial DNA.

  • Make many copies of the desired piece of DNA.

  • Sequence the DNA.

  • Analyze the sequence and identify the bacteria.

The piece of DNA used for identifying bacteria is the region that codes for a small subunit of the ribosomal RNA (16S rRNA). We will refer to this piece as 16S rDNA. Different bacterial species have unique 16S rDNA sequences. The identification relies on matching the sequence from your sample against a database of all known 16S rDNA sequences. (Learn more about ribosomal RNA.)

Learning Objectives

  • What kind of patient samples are used for the purpose of identifying possible pathogens?

  • What does PCR do, how does it work, and why is it useful?

  • How do you separate the desired DNA from all others?

  • How does an automatic DNA sequencer work?

  • Why is it possible to use a DNA sequence to identify bacteria?

Throughout each exercise, this window will display information explaining what you are doing. All the interactions, however, will be done inside the graphic window to the left. The small white box below the graphic will give you specific instructions on what objects to click on.

 

How Big is a Bug?

This experiment illustrates the differences in size between bacterial cells and virus particles - a classic microbiology experiment.

Pink Bugs, Purple Bugs

Perform the Gram stain procedure and identify some bacteria from the LabWork rogues gallery.

Bacterial Growth Curve

Determine the rules which control bacterial growth: the growth rate constant and the mean generation (doubling) time.

Viruses Don't Grow

Perform a classic experiment which demonstrates the principles of virus replication.

Influenza Virus Haemagglutination

Measure the amount of virus produced and determine the antigenic type of an unknown strain.

Henrietta Lacks

Who dunnit? Find out using PCR!