Random gene mutagenesis for gene identification linked to prodigiosin production in Serratia marcescens
Verena Carvalho, University of Massachusetts-Amherst
This lab course is designed to provide course-based undergraduate research experiences. You will learn how to prepare, execute, and interpret your own experiments. While all of you will conduct the same techniques in the course, each of you will create their own sets of mutant strains and study different features of your bacterium. We will study Serratia marcescens, an opportunistic, nosocomial pathogen, and is particularly linked to catheter-associated bacteremia, urinary tract infections, and wound infections. It is responsible for 1.4% of hospital-acquired infection cases in the United States. These bacteria are commonly found in the respiratory and urinary tracts of hospitalized adults, and in the gastrointestinal systems of children. Many strains of S. marcescens have a bright red colony color (a tripyrrole pigment called prodigiosin), while pigment production is often temperature-dependent. Prodigiosin is a secondary metabolite, and its expression is thought to be related to phosphate limitation. It was also identified as a natural bioactive substance with high potential for antibiotic and anti-cancer applications. It currently receives renewed attention for its wide range of potential applications, including activities as antimalarial, antifungal, immunosuppressant, and antibiotic agents. It is also prominently known for its capacity to trigger apoptosis of malignant cancer cells, and high activity against stationary phase Borrelia burgdorferi, the causative agent of Lyme disease, has been demonstrated. Given its diverse effects, the exact mechanisms are currently not elucidated, and may be highly complex, including phosphatase inhibition, copper mediated cleavage of double stranded DNA, or disrupting the pH gradient through transmembrane transport of H+ and Cl- ions. Clearly, prodigiosin is a highly promising drug candidate, and is currently in preclinical phase study for pancreatic cancer treatment. In this course, we will use the transposon Tn5 to generate random mutations in the chromosome of Serratia marcescens. The transposon will be provided by a plasmid hosted in a donor E. coli strain, and transferred into your test bacterium via conjugation. We will then first select for successfully transposed mutants by testing for antibiotic resistance, and screen for your mutants that are altered in their pigment production. To identify the gene where the mutation has happened, we will remove the chromosomal DNA from the mutant strains, perform restriction enzyme digest, and generate self-circulating DNA. These plasmids are transformed into an E. coli strain that can replicate the fragment of genomic DNA that contains the transposon, and we can sequence the insertion site with the transposon DNA as anchor. In summary, in this course you will gain hands-on experience with modern genetic and biotechnological techniques, you will gain insights into bioinformatics and into working with public databases, which are all essential skills in modern microbiological research.

Water in Gen Chem
Ruthanne Paradise, University of Massachusetts-Amherst

Optimizing Pedal People
Annie Raymond, University of Massachusetts-Amherst
This course is an introduction to mathematical modeling. The main goal of the class is to learn how to translate large broadly-defined real-world problems into quantitative terms for interpretation, suggestions of improvement and future predictions. Since this is too broad of a topic for one semester, this class focuses on linear and integer programming. The course is centered around a research project that involves optimizing different aspects of the bike-powered trash-recycling-compost-collection service Pedal People.