Army Research Office -- Coevolutionary complex networks: dynamical foundations, influence, and control (2014-2019)

  • The research will develop theoretical methods, modeling approaches, and computational algorithms for coevolutionary network dynamics, influence, and control, and will be organized around the following research themes: (i)Dynamical foundations of coevolution; (ii) network influence and control; (iii) host-viral interactions. This research has also catalyzed the development of new approaches to viral-based control of bacterial infections via immunophage synergy.

National Science Foundation - Biological Oceanography (2018-2021)

Dimensions: Costs and benefits of chronic viral infections in natural ecosystems (2013-2018)

  • This research project will investigate a new hypothesis about how viruses may control the structure and function of microbial communities. The traditional view of viruses is that they negatively impact the fitness of infected hosts. In other words, they are viewed strictly as pathogens, in which the host tries to eliminate the virus. This project will explore an alternative hypothesis: that chronic viral infections contribute positively to host fitness, increasing the success of the virus-host pair by protecting their hosts from infection by even more pathogenic viruses.

Physics of Living Systems -Synergistic Elimination of Bacteria by Immune Cells and Viruses (2018-2021)

  • Joshua Weitz is PI of a new NSF project to develop an integrated approach to understand the physics of complex interactions amongst phage, bacteria, and innate immune effector cells. This project will combine theory of nonlinear dynamics, computational simulations of living systems, and in vitro experiments. Joint w/Jennifer Curtis (Co-PI, Georgia Tech Physics).

Simons Foundation: Viruses vs. zooplankton: quantifying the interplay between parasites and predators in the North Pacific Ocean (2014-2020)

  • Marine viruses affect microbial community structure and biogeochemical cycles in multiple ways: (i) by negatively affecting, and potentially limiting, the density of target populations; (ii) by modifying the metabolic activity of infected cells, including nutrient uptake rates; (iii) by stimulating production via the “viral shunt”, in which cellular lysates are released back into the environment and then re-assimilated by non-targeted cells. Yet inferring the relative importance of virus-induced modifications of microbes and microbial cell fate is difficult in the face of competing ocean processes, e.g., grazing by zooplankton.In this collaboration, the Weitz group will leverage theory- and simulation-based approaches to quantify the relative importance of viruses relative to that of zooplankton in regulating microbial mortality and modifying ecosystem functioning in a model ocean environment: Station ALOHA. This work is part of a multi-PI project the "Simons Collaboration on Ocean Processes and Ecology" aka SCOPE.