Food Safety, Security, and Analytical Methods

The Avis Lab studies both fundamental and applied aspects of food and plant microbiology. More specifically, we are interested in microbial food spoilage and plant pathology. Our main focus is the use of alternatives to synthetic chemicals to control the growth of microorganisms on crops and during food storage. The resulting effects of this research is meant to increase food yield and reduce food loss, which can have a positive impact on food security and environmental sustainability.

We are investigating the use of beneficial microorganisms (biological control agents), as well as microbial and plant extracts and purified natural antimicrobial compounds as potential alternatives to control harmful microorganisms. These novel control measures are meant to mitigate problems associated with some synthetic control measures such as risks to health and the environment as well as to delay or eliminate the onset of resistance development in the targeted microorganisms.

Our laboratory uses a multidisciplinary approach including basic microbiology, biochemistry, bio-analytical and bio-physical chemistry, membrane and lipid chemistry, as well as molecular biology, genetics, and genomics.

Dr. DeRosa’s Lab, the Laboratory for Aptamer Discovery and Development of Emerging Research (LADDER), seeks to develop biosensors and “smart” materials based on DNA aptamers, single stranded DNA or RNA sequences that specifically bind to a diverse variety of targets. Projects in our lab draw on inorganic, organic, materials, and nucleic acids chemistry. Several main research themes are outlined below:

1. Human and Ecosystem Health: We have several projects where we apply our aptamer technology to problems in health. We have developed MRI and CT contrast agents that use aptamers for targeting. Working with colleagues in neuroscience, we have developed an aptamer-based tool to study, and perhaps one day treat, Parkinson’s Disease. We have also discovered aptamers for
2. Molecules and materials for sustainability: Our research on aptamers for controlled release applications is being to “smart” fertilizer technology. Fertilizers play a critical role in increasing agricultural outputs but at high economic and environmental cu_event_costs. The smart fertilizer concept involves the use of aptamers to recognize chemical signals that are exuded from crop roots to trigger the release of nutrients on demand, lowering cu_event_costs for the farmer and lessening environmental impact.
3. Food Safety, Security, and Analytical Methods: The presence of unsafe levels of contaminants in food is a growing public health problem that requires new technology for monitoring the food continuum from production to consumption. Aptamers for food safety targets, such as parasites, bacteria, and mycotoxins, have been discovered and tested in the LADDER. Our main interest is to develop low‐cu_event_cost, sensitive, robust biosensors for the detection of targets, mycotoxins in particular, at early stages in the food production chain (e.g. farm and grain elevator).

For more information, visit the LADDER.

Our group is broadly focused on synthetic organic chemistry, particularly on applications in biochemistry and engineering. Our approach to research is highly collaborative with other academic researchers and corporate partners.

In partnership with Prof. Jeff Smith in Chemistry, we developed TrEnDi (Trimethylation Enhancement using Diazomethane, which uses innovative applications of diazomethane to enhance the analysis of certain biological molecules, particularly certain lipids and peptides, via mass spectrometry through the introduction of fixed, permanent positive charge(s). cu_people_phone_ext and expansion of this work is ongoing, with current directions focused on the development of new derivatization reagents, expansion of the scope of substrates suitable for derivatization, and facilitating new fragmentation pathways in tandem mass spectrometry that will facilitate structure identification.

Our group is also currently engaged in a collaboration with Prof. Ron Miller (Carleton University, Department of Mechanical and Aerospace Engineering) to understand the chemical fate of antioxidants in lubricating oils. This work involves the synthesis of various compounds proposed to be the oxidized antioxidants. This work is aimed at improving the understanding of how lubricants are oxidized and their functional lifetimes.

Our group’s expertise and previous work encompasses the total synthesis of natural products, including lipids, polyketides and terpenes; as well as methodologies, including metal-catalyzed organic processes.

For more information, visit the Manthorpe Lab.

Overview

Mass spectrometry (MS) has proven to be a powerful analytical tool in many scientific fields for nearly a century. Advances made in soft ionization techniques such as electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) have expanded the use of MS to the biological sciences, allowing biomolecules to be ionized and sampled in the gas phase without fragmentation. These advances have been echoed in an explosion of publications over the past 20 years that have used MS as a tool to illuminate information pertaining to a biological question. The majority of MS-based bioanalytical studies to date have focused on cataloguing the species present in a sample at a static moment in time. Although this is important, measuring the dynamics of a system in response to a stimulus not only aids identification efforts, but offers mechanistic insight into the cellular processes involved. Gaining a better understanding of these dynamics, often expressed through a change in concentration or in the degree of modification, enhances the accuracy of cellular models, assigns functional roles to the identified species, as well as highlights new diagnostic and therapeutic strategies. The research program of the Smith group focuses on developing novel methods to efficiently measure biomolecular dynamics in living systems with the downstream goals of elucidating disease biomarkers and further characterizing biosynthetic and biochemical pathways.

Instrumentation

The Smith Lab uses mass spectrometry as a tool to probe the dynamics of various biomolecules. At present, we mainly conduct research in the area of protein analysis (“proteomics”) and lipid analysis (“lipidomics”). The laboratory is equipped with high-resolution hybrid quadrupole time of flight, triple quadrupole and linear ion trap mass spectrometers. All of these instruments achieve ionization via electrospray ionization and are coupled to high performance liquid chromatographs. The lab additionally houses two gas chromatography-MS systems, one equipped with a headspace sampler.

TrEnDi

Trimethylation Enhancement using Diazomethane (TrEnDi) is a published technique developed by Professors Jeffrey Smith and Jeffrey Manthorpe at Carleton University. The method increases the sensitivity of mass spectrometric detection by assigning a fixed, permanent positive charge to amino groups. It allows for increased and predictable sequence coverage for peptides in proteomic analyses, and increased limits of detection for several important lipid classes in lipidomic analyses.

Wasslen, K.V., Canez, C.R., Lee, H., Manthorpe, J.M., Smith, J.C. (2014) Trimethylation Enhancement using Diazomethane (TrEnDi) II: Rapid In-Solution Concomitant Quaternization of Glycerophospholipid Amino Groups and Methylation of Phosphate Groups via Reaction with Diazomethane Significantly Enhances Sensitivity in Mass Spectrometry Analyses via a Fixed, Permanent Positive Charge. Analytical Chemistry. Oct 7;86(19): 9523-9532. DOI: 10.1021/ac501588y. PMID: 25208053.

Quantitative Proteomics

The Smith Lab uses microfluidic devices to manipulate biological samples in a highly efficient manner to elucidate protein dynamics and post-translational modification patterns using MS in conjunction with TrEnDi. Through studying the dynamics of protein abundances or the modes in which they are modified in cells that are stimulated in some manner (or that are either diseased or healthy), our research will help define how cells communicate with each other, their environment and themselves.

Quantitative Lipidomics

Although lipids have been studied for decades and have been largely regarded as energy storage or structural molecules, recent progress in lipid research has revealed many novel and important roles for lipids in cellular signaling. Many classes of lipids are easily analyzed by mass spectrometry; however, some are more difficult to observe. The Smith Laboratory will focus on developing novel methods to identify lipid species in the context of complicated biological samples. To date, the development of TrEnDi has achieved this goal by increasing the sensitivity of some lipid classes over an order of magnitude. Ultimately, we will apply the novel methods that are developed to investigate lipid dynamics in biological systems to aid our understanding of the roles they play in cellular life.

For more information, visit The Smith Lab.

The Hosseinian Group conducts research in the area of phytochemistry/food biochemistry, focusing on:

• The extraction and characterization of novel biomolecules (mainly phenolic lipids and their interaction with dietary fibre) from agri-food by-products/waste;
• Investigating their structure-function relationship (biotransformation) in microemulsions/encapsulations in food and biological membranes (liposomes/artificial cell membranes);
• Enhancing antioxidants and anti-inflammatory activity for human health and well-being;
• Applying techniques (e.g. fermentation and germination) to reduce anti-nutritional factors in foods;
• And developing biomaterails from agri-food by-products/waste.

These novel biomolecules can have considerable potential for food science, agriculture, cosmetic, pharmaceutical, animal science and health science applications. Our lab is now more than 90% solvent free with innovative green techniques (SC-CO2 and Ultrasound) used to extract biomolecules.

Using analytical and bioanalytical chemistry, the Lai Group focuses on the instrumental analysis of biochemical and environmental samples for public health using capillary electrophoresis, dynamic light scattering, fluorescence spectroscopy, gel permeation chromatography, liquid chromatography, mass spectrometry and 3D microfluidics. New photochemical, electrochemical and optical phenomena are developed into analytical methods for enhanced sensitivity and selectivity: (a) molecularly imprinted polymers for the selective determination of therapeutic drugs in serum, ochratoxin A in red wine, and estrogenic compounds in wastewater treatment by solid-phase extraction with differential pulsed elution; (b) self-assembled monolayers and electropolymerized thin films for adsorption of toxic metals (Hg²⁺) and mycotoxins; (c) functionalization of colloidal nanoparticles for removal of endocrine disrupting compounds in environmental water and radioactive nuclides (Pu-238, Sr-90, Y-90,) in urine; (d) detection of nanoparticles in environmental water and air samples; (e) DNA binding with inorganic oxide nanomaterial surfaces; (f) interaction of nanoparticles with graphene quantum dots and simulated lung fluid; (g) surface chemistry/biochemistry of nanoparticles as related to electrochemical analysis by cyclic voltammetry and electrochemical impedance spectroscopy.