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Chad Johnston, McMaster University

New Techniques Facilitate the Discovery and Study of Modular Microbial Natural Products

Antibiotic resistance is the single most serious threat facing modern healthcare today. Increasing resistance is rendering our current antibacterial arsenal useless at a time when almost no new antibiotics are being developed. As such, a consensus is forming that we are now entering a post-antibiotic age, where otherwise minor infections from cuts and scrapes could prove fatal. To save modern medicine, we must find new antibiotics that can overcome resistance and form the basis for the next generation of therapeutics.

Nearly all of the antibiotics we use today are “natural products” that were originally isolated from microorganisms during the mid-1900s using cutting-edge approaches of the day. Although initially successful, these old discovery methods have been yielding diminishing returns since the 1970s, leaving us now with a lack of new antibiotics we can use to overcome resistant bacteria. Despite the gloom, a revolution in genome sequencing has demonstrated that there are potentially many more natural products left that could form the basis for a new generation of antibiotics if we could access them. In my doctoral thesis, I pioneered new techniques to use new big data analytics and computer automation to reveal these new antibiotics, providing tools that are poised to dramatically increase the rate of drug discovery and push back the tide of antibiotic resistance.


Leif Fredrickson, University of Virginia

The Age of Lead: Metropolitan Change, Environmental Health, and Inner City Underdevelopment

This dissertation uses lead hazards as a case study to explore the relationship between metropolitan development, environmental health, and social inequality. It shows how suburbanites and suburban development benefited from lead-related technologies such as lead piping, lead-solder, lead-acid batteries and leaded gasoline. These benefits were often not shared by those in the inner city. Moreover, the costs of lead pollution from these technologies – which included everything from short-term, acute medical emergencies to long-term chronic health and cognitive problems – were imposed disproportionately on inner-city residents. This was particularly true of leaded gasoline used by suburban commuters. But the production and recycling of other lead products, such as lead-acid batteries, was also concentrated in the inner city, and so was the pollution from these products. In addition, suburbanization increased lead poisoning in the inner city by accelerating housing deterioration, which exacerbated lead paint hazards. Some suburbanites benefited directly from this housing deterioration through their profitable ownership of slum housing in the inner city. In addition, suburbanites were able to carve out more environmentally healthy environments on the metropolitan periphery. These dynamics were self-reinforcing. For example, automobile pollution concentrated in the inner city pushed more people to move to the suburbs, which created more automobile pollution in the inner city when those suburbanites commuted. Ultimately, this dissertation examines how one element, lead, linked the environment, metropolitan expansion, the state, and capitalism over the course of a century, providing a window into the tradeoffs that shaped the lives of millions.