UWinChemBiochem Seminar Series - Winter 2018
André J. Simpson
Friday, Jan. 12, 2018 @ 3:00 p.m.
**Everyone Welcome**
Department of Chemistry
University of Toronto
Title: “From Structure to Interactions to In vivo NMR: The vast potential of NMR Spectroscopy in Environmental Research”
Web: http://www.utsc.utoronto.ca/~asimpson/
Room #186 Essex Hall
Abstract:
NMR spectroscopy is arguably the most powerful tool for elucidating
structures and probing molecular interactions. Practically all environmental
research, at least to some extent, involves working with ultra-complex natural mixtures
that are ubiquitous in soil, water, and air. NMR can provide information not
only as to the basic chemical structures present in a mixture, but can
potentially provide information as to the self-associations of molecules
(aggregation and flocculation processes), their mechanistic interactions with
xenobiotics (transport of contaminants) and provide the direct connection
between molecular scale processes (environments of individual nuclei) and
macroscopic scale (visual), in the form NMR imaging.
This presentation will take the audience through an evolution of my
career from molecular-structure at one extreme to the impact of chemicals in
living systems at the other.
Structure: Understanding the structure of soils, air particles, and dissolved
organic is a critical precursor to understanding how these materials function. This
information is desperately needed to develop the most efficient soil
remediation and agricultural practices as-well as better predict carbon
sequestration and climate change.
Interactions: With a better understanding as to the structural components and NMR
assignments for key environmental matrices it is then possible to determine,
how, where, and why contaminants get sequestered and are challenging to
remediate. A range of novel NMR experiments will be introduced along with a new
technology termed comprehensive multi-phase NMR. Comprehensive Multiphase (CMP)
NMR, was co-developed between my group and Bruker Biospin. The approach
combines all the electronics from solution-state, semi-solid and solid-state
NMR into a single NMR probe. The resulting technology permits an uncompromised
analysis of liquid, semi-solid and solid components within unaltered samples in
their natural swollen state. As well as unravelling the binding orientation,
and receptors for contaminants/drugs CMP-NMR is also capable of monitoring the
kinetic transfer between and across interfaces providing an unprecedented
window into otherwise inaccessible molecular information.
Impact: With an understanding as to “what soil is?” and “which chemical components bind contaminants?" the key questions become “what does it all mean?” and “how are living systems impacted?”. For example, if a herbicide is bound tightly to the protein fraction of soil is it still bioavailable? Would this still hold true with climate change or change in land use? An even more challenging but important question is “out of the 100’s or 1000’s chemicals we are exposed to everyday which ones truly impacts our health?” Indeed similar questions are asked everyday by policy makers. NMR has great potential to address such challenges when employed as the “molecular interpreter” of living systems under environmental stress. In this final section in-vivo NMR is introduced on small invertebrates. Static studies (i.e. using a flow system and solution-state probes) provide a low stress environment to study metabolic flux in response to stressors. Conversely, CMP-NMR, can potentially be used to study and differentiate different phases (liquids (metabolites), gels (proteins, membranes), solids (shell, bone)) in-vivo. A wide range of novel experiments will be introduced that greatly improve the depth and breadth of information that can be obtained from NMR of living systems. Combined the approaches hold the potential to identify which are the most potent environmental stressors in complex natural samples, explain their toxic-mode-of-action and even act as early warning system to identify environmental stress, prior to disease, or ecosystem shifts.
Impact: With an understanding as to “what soil is?” and “which chemical components bind contaminants?" the key questions become “what does it all mean?” and “how are living systems impacted?”. For example, if a herbicide is bound tightly to the protein fraction of soil is it still bioavailable? Would this still hold true with climate change or change in land use? An even more challenging but important question is “out of the 100’s or 1000’s chemicals we are exposed to everyday which ones truly impacts our health?” Indeed similar questions are asked everyday by policy makers. NMR has great potential to address such challenges when employed as the “molecular interpreter” of living systems under environmental stress. In this final section in-vivo NMR is introduced on small invertebrates. Static studies (i.e. using a flow system and solution-state probes) provide a low stress environment to study metabolic flux in response to stressors. Conversely, CMP-NMR, can potentially be used to study and differentiate different phases (liquids (metabolites), gels (proteins, membranes), solids (shell, bone)) in-vivo. A wide range of novel experiments will be introduced that greatly improve the depth and breadth of information that can be obtained from NMR of living systems. Combined the approaches hold the potential to identify which are the most potent environmental stressors in complex natural samples, explain their toxic-mode-of-action and even act as early warning system to identify environmental stress, prior to disease, or ecosystem shifts.
