Oxidative stress has been suggested to be the primary toxic pathway of air particulate matter (PM) to cause cardiovascular disease and other adverse effects. In this talk, oxidative stress was demonstrated as the primary toxic pathway for both disinfection by-products (DBPs) in drinking water, and oil sands-processed water (OPSW). To this end, a hybrid platform was established in our group to identify toxic components and their modes of action (MOA) from these critical environmental matrices. High-throughput and reproducible in vitro cell reporter system was used to determine the Nrf2-mediated oxidative stress response from environmental mixtures. Then, Effect-Directed Analysis (EDA) and chemical probe, combined with untargeted chemical analysis, were used accordingly to identify toxic components. Specifically, more than 600 DBPs were identified in the drinking water after disinfection and direct reaction with cysteine was elucidated as the primary pathway for DBPs to cause oxidative stress. Accordingly, a biotin/cysteine chemical probe was synthesized to identify toxic DBPs. For OSPW whose oxidative stress may primarily be caused by indirect pathways, EDA combined with untargeted chemical analysis was used to identify hydroxylated aldehydes as the primary toxic components. Studies regarding PM samples are still ongoing, and preliminary data shown that chemical probe is an efficient approach to identify toxic components (i.e. quinone) in PM samples. Thus, our hybrid platform may provide a versatile and accessible approach in elucidating the oxidative stress promoting components in a variety of environmental matrices.
DETAILS: Uoft.me/SOCAAR1NOV17
Design of bioswitches and cellular robots for metabolic engineering and synthetic biology
Professor An-Ping Zeng,
Institute of Bioprocess and Biosystems Engineering,
Hamburg University of Technology
Despite impressive progresses in systems metabolic engineering and synthetic biology there are still several unsolved major problems in their practical applications for developing effective metabolic pathways and microorganisms for biosynthesis, including:
- identification of targets for advanced pathway engineering of productive strains, especially under industrially relevant and in vivo conditions;
- effective means with proper dynamic range and sensitivity for dynamic and concerted control of metabolic pathways;
- designed elements or devices from synthetic biology often not work well within the host cells, especially for highly productive strains;
- mathematical models of cellular processes often miss regulatory details inside cells and thus fail to guide biomolecular and cellular design.
In this presentation, I will illustrate some of our recent efforts to address these questions. First, I will present results on rational design of bioswitches (riboswitch and ligand-introduced allosteric regulation) with improved dynamic range and sensitivity for dynamic control of metabolic pathways. Then, I will address the question how we can use the host cell as “a computer or robot” to identify targets, evaluate designed parts and even to evolve the best design for a specific purpose? Cells are capable of information processing, rapid replication and performing tasks adaptively and ultra-sensitively. The key issue is how to let the cells “to compute or evaluate” the processes we are interested in and how “to output” the right results corresponding to the different inputs? To this end, we have used E. coli as an example to rein the computation abilities of cells by designing high throughput input and sensitive output systems based on its interaction with bacteriophage. The method is successfully demonstrated for target identification, evaluation of designs, evolution and selection of key enzymes for lysine bioproduction in E. coli.
“Optimising Structure-Property Dependencies of Stochastic Materials by Probabilistic Modelling”
William Sampson, University of Manchester
ChemE’s Plant Design presentations start TODAY! ALL are welcome to attend
Plant Design is our fourth-year capstone design course where students work in teams to create a preliminary design for a chemical plant, including generating a detailed economic analysis. The course brings together everything they’ve learned throughout their undergraduate education.
Presentations are held in the Wallberg Building (WB) and the Bahen Centre (BA), both located on the St. George Campus.
Check out the schedule for details: https://tinyurl.com/capstonedesign2017
“Megasupramolecules”
Julia Kornfield, California Institute of Technology
Extreme heat is a significant health risk for a large proportion of Toronto’s population. Heat-vulnerable groups include children, older adults, people who are socially isolated or have low incomes, including those who are experiencing homelessness. Toronto Public Health estimates that extreme heat contributes to an average of 120 deaths per year in Toronto and that could increase with climate change. This presentation will highlight work that Toronto Public Health is undertaking to help address the risks of extreme heat including climate forecasting, heat vulnerability mapping, population surveillance, hot weather response and community outreach. Policy opportunities and data needs will also be discussed.
“CO2-Switchable Materials”
Philip Jessop, Queen’s University
Industrial inefficiencies, causing wastage of energy and materials, are often the result of failures to resolve time-separated conflicting requirements. For example, a drying agent particle must to strongly absorb water from something that needs to be dried, but must easily release the water when the drying agent is being regenerated. Switchable materials can solve such problems. Waste CO2 is a renewable material that can be used to reversibly trigger changes in the properties of liquids, solutes, or surfaces. This presentation will portray two different classes of switchable materials, a class of switchable solvents and a series of switchable surfaces, and discuss how their design and use can help solve practical problems (e.g.water purification, paints and coatings) while reducing environmental impact.
Prof. Cora Young
Assistant Professor
Department of Chemistry York University
Atmospheric particles with a large fraction of water soluble carbon contain organic species that absorb solar radiation. This wavelength-dependent absorption leads to a brown colour and the term brown carbon (BrC). Molecules that comprise BrC have been likened to humic substances because of the similarity between their UV/vis absorption spectra, but are otherwise poorly characterized complex mixtures. To better understand the structural characteristics of BrC, we applied techniques used for the analysis of humic substances to various real aerosol extracts likely to contain BrC. These samples were collected from biomass burning plumes of various ages (collected in Vancouver, BC and St. John’s, NL) and background air from the SOAS campaign. Using i) ultra-high resolution mass spectrometry and ii) size-exclusion chromatography coupled to UV/vis and mass spectrometry detection, we can improve our understanding of the structures that comprise BrC and their likely sources. With the first application of size-exclusion chromatography-UV/vis to BrC samples, we have unambiguously shown the prevalence of extremely low volatility organic compounds (ELVOCs) in BrC, with masses up to 10,000 Da. Within size-resolved aerosol samples, we observed that BrC and typical biomass burning markers were externally mixed. The molecular size distribution of BrC compounds was conserved between aerosol samples of different origin, including background aerosol from SOAS, suggesting most BrC is derived from biomass burning. Insights regarding molecular composition of BrC, aging, and the limitations of mass spectrometry in detection and characterization of BrC will be discussed.
“CleanTech Meets FinTech: A Data-Driven e-Ship Disruption in Environmental Engineering”
Peter Adriaens, University of Michigan
Prof. Sarah Styler
Assistant Professor
Department of Chemistry University of Alberta
Road dust is a major source of primary particulate matter in many urban centres. Since road dust contains a variety of toxic species, including heavy metals and polycyclic aromatic hydrocarbons (PAH), studies of this substrate performed to date have primarily focused on its composition and potential health effects. Although laboratory studies have shown that desert dust can act as a photocatalyst, little is currently known regarding chemistry and photochemistry at the road dust surface. Here, we report production of singlet oxygen (1O2), an important environmental oxidant, by aqueous suspensions of size-fractionated road dust collected in Edmonton, Canada. In addition, we present results from coated-wall flow tube investigations of ozone uptake by winter street sweepings. Together, these results suggest that road dust photochemistry has the potential to influence both the lifetimes of pollutants present at the dust surface and the composition of the surrounding atmosphere.