APPLYING MOLECULAR BIOLOGY TECHNIQUES TO ASSESS BACTERIAL INFECTION: A HIGH SCHOOL UNIT

This unit consists of project-based lessons aimed at aiding high school teachers to review with their students the more salient concepts in immunology, such as the mechanisms and effects associated with inflammation, through the use of molecular biology techniques. The immune system is designed to protect the body from all kinds of environmental threats, including viruses, toxins, and allergens. When the first line of defense fails, an array of inflammatory responses is initiated. Unfortunately, the immune system is not always successful at eliminating the enemy. In the first project, students read and assess a fictional case study describing a patient’s symptoms and blood chemistry to a hypothetical infection. Students will work on worksheets, quizzes and homework assignments emphasizing their understanding of specific leukocytes associated with the innate and adaptive lines of immunity and how immune responses are generated against specific extracellular pathogens such as bacteria. In order to confirm that the infection is indeed of bacterial origin, students will perform polymerase chain reaction amplification targeting the bacteria’s 16S rRNA gene. For these bacterial based case studies, students are given bacterial genomic DNA to amplify, resulting in amplified 630 bp amplicon. In the other case studies not involving bacterial infection such as viral infection or allergic reaction, students are given water to pcr amplify, resulting in no amplicon (except for the positive control). In a follow up case study, students will read about another patient who is infected with a bacterium, normally responsive to penicillin, but for an unknown reason is not this time. Students perform a restriction enzyme digestion (EcoRI and HindIII) on the bacteria’s plasmid DNA; a released 2635 bp band (beta-lactamase) confirms that this pathogen has evolved penicillin resistance. Based on these results, students learn that a new prescription is required. This activity further helps students see the impact of gene expression on an organism’s phenotype. Each day during this project, students will work on worksheets, quizzes and homework assignments emphasizing their understanding of immunity and the roles of specific immune cells. After students have completed the project including having reviewed their patient’s symptoms, the referring physician’s comments, any unusual blood count values and the pcr-amplification results, they will communicate a final diagnosis report based on their results and the understanding of immune responses to environmental threats to other classmates in a culminating conference day.