Sarah Kronheim
Ph.D. Candidate
Hello!
I'm Sarah, a scientist specializing in the fascinating world of bacteriophages. I investigate the complex interactions between these viruses and the bacterial hosts they infect. By studying the unique features and behaviours of bacteriophages and Streptomyces, I aim to contribute to the growing body of knowledge that will revolutionize the way we understand exactly what is happening in the world of the smallest known microbes.
Education
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Data Analytics Certificate, University of Toronto
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Doctor of Philosophy Candidate in Biochemistry, University of Toronto
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Bachelor of Science in Biochemistry and Molecular Biology, University of Maryland, Baltimore County
Experience
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Ph.D. Researcher, University of Toronto
- Developed and optimized a phage propagation assay using Streptomyces-specific phages and Streptomyces coelicolor to determine the effect of compounds on phage propagation
- Optimized purification of compounds from whole cell extracts of several species of Streptomyces via HPLC and characterized the impact of resulting compounds on phage infection using a set of assays to isolate the stages of the phage lifecycle
- Sequenced, annotated, and bioinformatically analyzed genomes of 12 isolated phages that infect Streptomyces and characterized their infection phenotype and host range
- Discovered an anti-phage function of Streptomyces xenogenic silencing proteins and a role for phage-encoded xenogenic silencing proteins in overcoming anti-phage defense using plaque assays and heterologous expression of phage proteins in Streptomyces
- Discovered the mechanism which two phage proteins overcome anti-phage defense by Streptomyces xenogenic silencers via protein expression and co-purification experiments, electrophoretic mobility shift assays, and bioinformatic analysis
- Mentored, trained, and led projects for 4 undergraduate and 4 rotation students
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Formulation Associate I, National Institutes of Health - Vaccine Production Program
- Optimized PEG solubility assay protocol via literature review, modification of assay protocol, and research into liquid handling machines
- Determined optimal solubility conditions for several vaccine candidates via PEG solubility assay
- Trained a new hire on PEG solubility assay
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Research Assistant, Fina BioSolutions
- Optimized purification of proteins via affinity (Nickel, eXact, Heparin-like resin) and ion exchange (Q, DEAE resin) liquid chromatography and analyzed resulting proteins with ELISA, SDS-PAGE, Western blot, and spectrophotometry
- Transformed and expressed plasmids in E. coli in a 1L fermentor and ran tangential flow filtration (TFF) to concentrate and buffer exchange protein samples for purification
- Drafted SOP and Batch Record for a purification process, experimental and batch record keeping
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Research Assistant, US NewWin
- Analyzed plasmids using PCR and agarose gel electrophoresis, tansformed plasmids into E. coli, and expressed proteins from E. coli using a 1L fermentor
- Purified proteins from E. coli using affinity chromatography and analyzed using SDS-PAGE, BCA, Bradford, and colorimetric activity assays
- Copyedited product information sheets and business e-mails distributed to clients
Research Techniques
Bacteriophage Propagation and Genomics
Proficiency propagating a wide array of bacteriophages on several strains of Streptomyces and Escherichia coli. Experience with bacteriophage sequencing and genomic analysis and comparisons.
Streptomyes Small Molecules
Investigation of Streptomyces metabolite elicitation, production, and interaction with bacteriophages.
Assay Development and Optimization
Expertise in adapting existing assays to new bacteria, bacteriophages, and purposes.
Protein Expression, Purification, and Characterization
Experience in cloning of phage and Streptomyces genes into E. coli plasmids to express and purify proteins of interest, and performing standard characterization assays on purified proteins.
Bacterial Growth Curves and Genetic Manipulation
Familiarity with growing and analyzing the growth curves of various strains of bacteria and transformation and conjugation of plasmids into them.
Bioinformatics
Broad expertise with bioinformatics including home-grown Python scripts to manipulate data, DNA and protein sequences, and lab equipment. Programmatic data analysis and visualization. Familiarity with prominent Python packages including Matplotlib and Seaborn, pandas, SQLAlchemy and Flask, and PySpark.
