One of MIT’s former SRP trainees, Jennifer Kay, was named the 23rd winner of the Karen Wetterhahn Award. This SRP-established annual award recognizes an outstanding graduate student or post-doctoral researcher that best demonstrates the qualities of scientific excellence exhibited by Dr. Wetterhahn. Kay says: “I aspire to her enduring legacy of research excellence, environmental concern, scientific mentorship, and social justice.” For more about Kay’s focus of studies, see the NIEHS Factor.
Congratulations to SRP trainee, Jessica Beard, and faculty member, Timothy Swager, for their publication in the Journal of Organic Chemistry! This is a pivotal paper for the MIT Superfund Research Program, both because it is tour de force in terms of the chemistry that is described, and also because it helps to inform cleanup. Importantly, it was written in response to members of the Wilmington Community who wanted to understand better whether or not N-nitrosamines are continuing to be formed at the Olin Chemical Superfund Site (located in Wilmington, MA). Being responsive to the community is key to the mission of the MIT SRP.
Jessica was also interviewed for a podcast by the Boston Museum of Science. Jessica shares her thoughts about her favorite molecule, her career aspirations, and her appreciation of the MIT Superfund Research Program. Listen to the podcast on the museum’s website website.
Amanda Armijo, a postdoctoral fellow at MIT Professor John Essigmann’s group in the Department of Biological Engineering and Dr. James Fox’s group in the Division of Comparative Medicine, is studying the genotoxic signatures caused by environmental contaminants and how these mutations result in development of liver cancer. Specifically, her research focuses on the mutational patterns induced by the probable human carcinogen, N-nitrosodimethylamine (NDMA). NDMA is key contaminant of the Superfund site in Wilmington, MA, which for many years has contaminated the drinking water from several municipal wells. As part of the MIT Superfund Research Program, Amanda is utilizing a high-fidelity duplex consensus sequencing (DS) method to reveal early onset genetic signatures of environmental toxicant-driven human diseases that occur later in life. Identifying these mutational processes can inform strategies for Superfund site remediation as well as clinical genetic disease early-detection, intervention and prevention.
These experiments are being performed in transgenic C57Bl/6 mice that contain a reporter gene to enable a mutational assessment and high-fidelity sequencing of the changes in the DNA triplets in the reporter gene region. To accomplish this, the transgenic mice are treated with a carcinogenic regimen of NDMA and then liver DNA is analyzed 10 weeks post-exposure (prior to development of cancerous lesions) with DS to produce high resolution mutational spectra (HRMS). DS is a highly accurate method to identify rare, unique mutations present in a heterogenous genetic milieu. Mutational spectra patterns will also be identified in lesions that have fully developed into pathological cancer induced by NDMA. Gene-environment interactions that define inter-individual variations in sensitivity to NDMA will be identified using mutational patterns.
Amanda received her Bachelor’s degree in Microbiology, Immunology, and Molecular Genetics from UCLA. After working as a laboratory technician, she entered graduate school at UCLA in the department of Molecular and Medical Pharmacology where her work focused on the link between nucleotide metabolism and DNA replication stress responses. Her graduate work subsequently led to the preclinical development of a panel of small molecule inhibitors of deoxycytidine kinase as an anti-cancer therapeutic. Amanda successfully defended her dissertation and next attended Cornell University’s College of Veterinary Medicine, receiving a Doctor of Veterinary Medicine degree. Following completion of her DVM, Amanda completed an internship in Laboratory Animal Surgery and Medicine at Tufts University. She is happy to have found a program at MIT that combines her interests in both caring for laboratory animals and in performing important research that can positively impact human health. In her spare time, she enjoys sports, volunteering for spay/neuter clinics, cooking, and spending time with her family.
Project 1 trainee Irene Hu successfully defended her thesis and will continue working with the SRP program as a postdoc. In the laboratory of Prof. Harry Hemond (Project 1), her research focused on the development and testing of a novel in situ sensor to measure benthic fluxes of key biogeochemicals, including pollutants at contaminated sites. Read more in her Trainee Spotlight here.
Project 4 trainee and RTC leader Dr. Jenny Kay was interviewed for a piece in the ASCO Post, published November 25, 2018. The ASCO Post has a circulation of ~35,000 health care experts. Ms. Kay described the relationships between inflammation and carcinogenesis, important aspects of MIT SRP biological research projects.
Projects 1 and 2 trainee Dr. Maggie He presented a talk at the American Chemical Society (ACS) National Meeting and Exposition. Her talk, “Functionalized carbon nanotubes for chemical sensor applications,” described a chemiresistive sensor platform that will be adapted to sense NDMA and PAHs in the environment.
Project 2 trainee Dr. Hélène Angot received an Early Career Presentation Award for her poster, “Towards reduced human exposure to mercury: The need for near-term global action,” at the Joint 14th Annual iCACGP Quadrennial Symposium and at the 15th IGAC Science Conference in Takamatsu, Japan. Hélène Angot also published a manuscript entitled “Global and local impacts of delayed mercury mitigation efforts” in Environmental Science & Technology (https://doi.org/10.1021/acs.est.8b04542).
Project 4 trainee Lizzie Ngo graduated with her PhD under the supervision of Profs. Bevin Engelward and Leona Samson (Project 4). Dr. Ngo’s innovative work includes development of a novel platform for detecting bulky DNA lesions, which is being used for studies of PAHs in collaboration with other MIT SRP researchers. The assay exploits DNA repair trapping to convert undetectable bulky lesions into single strand breaks that can be detected using the CometChip platform. Dr. Ngo also developed another technology that can be used for higher throughput cytotoxicity quantitation. The “MicroColonyChip” platform exploits methods to create a microarray of mammalian cells. Cells are allowed to grow to form microcolonies with precise inter-colony distances. The sizes of the colonies are then measured using a combination of automated imaging and in-house software. Dr. Ngo discovered that the distribution of microcolony sizes give rise to exquisite sensitivity to chemical toxicity, rivaling the gold-standard colony forming assay and the popular Cell Titer-Glo assay. The approach is broadly useful to the MIT SRP and the manuscript, “Microcolony size distribution assay enables high-throughput cell survival quantitation,” was recently published in Cell Reports. In addition to these innovative projects, Dr. Ngo also developed methods for studying DNA repair in lymphocytes. In collaboration with Dr. Zachary Nagel of the Harvard School of Public Health, Dr. Ngo analyzed repair kinetics for 50 different people. She observed significant differences in the DNA repair kinetics among different individuals, pointing to the possibility that DNA repair may be a susceptibility factor for exposure-induced diseases. Dr. Ngo is now an Associate at Flagship Pioneering, located in Cambridge, MA.
Irene Hu, a former graduate student in Professor Harry Hemond’s group at MIT in the Department of Civil and Environmental Engineering, is studying the flux of contaminants between sediments and water. Specifically, her research focuses on the development and testing of novel in situ instrumentation to study the fate and transport of environmental biogeochemicals. As part of Project 1 of the MIT Superfund Research Program, Irene is developing a sensor to measure benthic (sediment-water) fluxes of chemicals in aquatic ecosystems, such as pollutants from contaminated sediments at Superfund and other sites. Knowledge of such pollutant fluxes—including the location of the most problematic areas, and how quickly they are releasing toxins—is critical in to remediation efforts, including assessment of exposures and prioritization of cleanup efforts.
The sensor being developed is based on the eddy correlation technique, which involves correlating fast, simultaneous, and co-located measurements of velocity and concentration. To date, eddy correlation measurements of benthic fluxes have mainly been used to measure dissolved oxygen fluxes, using a dissolved oxygen microelectrode. To expand the range of measurable biogeochemicals, Irene has developed a novel trimodal sensor capable of high-speed, high-resolution measurements of fluorescence, temperature, and conductivity. Coupled to a velocity sensor for eddy correlation measurements, this instrument can be used to measure benthic fluxes of fluorescing materials, heat, and salinity. Thus, it can be used to target sediment-water fluxes of fluorescing pollutants in contaminated groundwater. In addition, it can potentially be used to measure benthic fluxes of a wider range of contaminants by using one flux as a tracer for others. The instrument has so far been used to measure simulated benthic fluxes in a laboratory setting, and will be tested in the field in the spring.
Irene has an undergraduate degree in electrical engineering from Princeton University; as a premed, her interests also extended to chemistry and biology. After graduating, she worked for a few years as a financial management consultant in New York City. She returned to graduate school to study environmental engineering because she wanted to work on projects that would have a positive impact on our environment and public health. She is happy to have found at MIT a research group that allows her to utilize her electrical engineering background for environmental applications, and she appreciates the wide range of skills and knowledge she has developed by working on her project—including electronics, programming, chemistry, fluid dynamics, machine shop work and fieldwork.
Irene Hu successfully defended her dissertation this past October and will continue working with the MIT Superfund program as a postdoctoral associate. In her spare time, she enjoys cycling, ballroom dance, and ice skating.
Dr. Hélène Angot is a postdoctoral associate at MIT in Professor Noelle Selin’s group. She investigates the atmospheric sources and fate of toxic global pollutants through observational and modeling tools. Toxic pollutants are emitted into air worldwide by multiple natural and anthropogenic sources. The atmosphere provides both a route of exposure (via inhalation) and a means for the long-range transport and transformation (e.g., oxidation) of pollutants in the environment. Through a modeling approach, Dr. Angot aims to draw the link between global emissions and local impact on Maine tribal areas.
Currently, Dr. Angot contributes to Project 2 of the MIT Superfund Research Program, aimed at modeling the atmospheric transport and fate of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and their degradation products (oxy- and nitro-PAHs). These compounds are present in Superfund and other contaminated sites, such as the Loring Air Force Base near Limestone, ME, making an understanding of their lifecycle especially relevant to the MIT SRP Center. While degradation products can be more toxic and harmful than their primary precursors, their atmospheric reactivity and fate is poorly understood. A fully coupled scheme is currently under development within the global chemical transport model GEOS-Chem. The ultimate outputs are model estimates of PAHs and degradation products’ atmospheric levels, which are crucial for improving estimates of potential exposures and public health impact. This work is done in close collaboration with Prof. Mathew Evans’ group at the University of York’s Chemistry Department (UK) and Prof. Jesse Kroll’s group at MIT.
In addition to PAHs, Dr. Angot also studies atmospheric mercury (Hg) transport and transformation. Upon deposition to ecosystems, Hg converts to highly toxic methylmercury (MeHg) and bioaccumulates in aquatic systems. Tribal communities are therefore particularly affected by Hg contamination due to their traditional dependence on subsistence fishing. The United Nations Minamata Convention on Hg entered into force last summer. Under this Convention and as a co-benefit on greenhouse gases mitigation policies, global Hg emissions are expected to decrease. Dr. Angot is investigating benefits attributable to this policy in terms of future local Hg deposition and fish contamination. In a scenario of delayed global action, benefits will decrease due to increasing legacy emissions (i.e., recycling of previously deposited Hg). These results underline the importance of near-term action for limiting the Hg burden of future generations.