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pGLO and Ampicillin Resistance Transformation of E. coli Inspire your students – tomorrow’s researchers CCTCA February 12, 2016 Ampicillin resistance and pGLO™ Transformation Bob Malyk BSc., MEd. [email protected] Biology Teacher (retired) Ridley College St. Catharines, ON Canada Bio-Rad (Canada) Life Science Education – Biotechnology Explorer Consultant GFP Workshop Timeline • Introduction • Transform bacteria with pGLO plasmid Why Teach Bacterial Transformation and Protein Purification? • Powerful teaching tool • Meet national science standards • Laboratory extensions • Real-world connections • Link to careers and industry Central Framework of Molecular Biology DNA RNA Protein Trait Links to Real-world • GFP is a visual marker • Study of biological processes (example: synthesis of proteins) • Localization and regulation of gene expression • Cell movement • Cell fate during development • Formation of different organs • Screenable marker to identify transgenic organisms pGLO™ Bacterial Transformation Kit Bio-Rad pGLO Kit Advantages • Standards-based • Comprehensive curricula for inquiry-based investigations • Compatible with 50 minute class periods • Serves entire class of 32 students (up to 4 students per group) • Cost effective $120.80 ($3.78/student) • Success in student’s hands • Safe • Striking results! Transformation Procedure • Suspend bacterial colonies in Transformation solution • Add pGLO plasmid DNA • Place tubes in ice • Heat-shock at 42°C and place on ice • Incubate with nutrient broth • Streak plates Transformation Procedure Day 1 Day 2 Volume Measurement pGLO Bacterial Transformation Kit What is Transformation? • 1928 Frederick Griffith • 1944 Avery and McLeod • Uptake of foreign DNA, often a circular plasmid GFP Beta-lactamase Ampicillin Resistance What is Transformation? F. Griffith 1928 What is a plasmid? • A circular piece of autonomously replicating DNA • Originally evolved by bacteria • May express antibiotic resistance gene or be modified to express proteins of interest The Many Faces of Plasmids Transmission electron micrograph Graphic representation Agarose gel Protein Size • Beta Lactamase – Ampicillin resistance • Green Fluorescent Protein (GFP) – Aequorea victoria jellyfish gene • araC regulator protein – Regulates GFP transcription Bacterial Transformation Cell wall GFP Bacterial chromosomal DNA Beta lactamase (ampicillin resistance) pGLO plasmids Bacterial DNA Bacterial cell Plasmid DNA Genomic DNA Transcriptional Regulation • Lactose operon • Arabinose operon • pGLO plasmid Transcriptional Regulation ara Operon lac Operon LacI Z Y A ara C Z Y A araC Y A B A D RNA Polymerase RNA Polymerase Z A D Effector (Arabinose) Effector (Lactose) LacI B araC B A D Gene Regulation ara GFP Operon ara Operon ara C B A D araC Effector (Arabinose) Effector (Arabinose) araC B A D araC RNA Polymerase araC B A D GFP Gene GFP Gene RNA Polymerase araC GFP Gene Methods of Transformation • Electroporation – Electrical shock makes cell membranes permeable to DNA • Calcium Chloride/Heat-Shock – Chemically-competent cells uptake DNA after heat shock Reasons for Performing Each Transformation Step? Ca++ Ca++ O O P O O CH2 Base O Sugar 1. Transformation solution = CaCI2 Positive charge of Ca++ ions shields negative charge of DNA phosphates O Ca++ O P O Base O CH2 O Sugar OH Why Perform Each Transformation Step? Cell wall GFP 2. Incubate on ice slows fluid cell membrane 3. Heat-shock Increases permeability of membranes 4. Nutrient broth incubation Allows beta-lactamase expression Beta-lactamase (ampicillin resistance) What is Nutrient Broth? • Luria-Bertani (LB) broth • Medium that contains nutrients for bacterial growth and gene expression – Carbohydrates – Amino acids – Nucleotides – Salts – Vitamins Grow? Glow? • Follow protocol • On which plates will colonies grow? • Which colonies will glow?