Mechanisms Enhancing Microbial Survival at Cold Temperature Phase Boundaries
Abstract
Once thought to be too extreme to support life, it is now known that icy environments support complex prokaryotic communities that meditate geochemical cycles in these environments. To date, most research has focused on the physical structure of ice, its geochemical composition, and the possibility for life in ice; however, this research has been constrained by technology. In the past, studies of the habitability of microbial life in ice have relied on melting ice and studying the bulk properties of the organisms released. At present, the challenge is how to address microbial scenarios as they appear in the environment. Recently, technological tools and methods directed towards monitoring in situ and intact samples have been developed permitting detailed studies under relevant conditions. We aim to apply these methodological advancements to cold temperature systems, which not only require high sensitivity methods but are challenging due to the solid ice matrix. Melting destroys the spatial organization of the habitat, dilutes the chemical constituents found concentrated in ice veins, and may change biochemical reactions which does not accurately reflect the high degree of organization of microbial communities in cold temperature habitats. Central to microbial activity in frozen habitats is the ability for microorganisms to survive in cold temperature environments. To do so, microbes employ a wide range of strategies to survive in the face of stressors such as low temperatures, resource limitation, low water availability, oxidative stress. and UV radiation. Many of these strategies are well known, with new methods shedding light on previously unrecognized cold temperature survival strategies. A novel mechanism that has been posited, but not yet demonstrated, is the role of cold active biosurfactants, which may play a significant ecological role, contributing to survival and carbon and nutrient turnover. The overarching goal of this proposed work is to investigate the microstructure of cold temperature habitats and how cold temperature phase boundaries in combination with cold active biosurfactants impact microbial metabolic strategies for growth and survival in low biomass cold temperature environments. Specifically, we propose six major goals: (1) Construct experimental reactors to simulate cold temperature phase boundaries (i.e., sediment:water, water:ice, and sediment:ice) to monitor rates of microbial activity. (2) Generate a genetically engineered biosurfactant deficient mutant. (3) Determine metabolic activity of the biosurfactant producing wild type and knockout mutant within, above, and below cold temperature phase boundaries. (4) Evaluate the impact of biosurfactants on the chemical properties and bioavailability of hydrocarbons. (5) Determine if biosurfactants enhance an organism s ability to tolerate extreme environmental stressors common to cold temperature environments (i.e., UV radiation and freeze-thaw cycles). (6) Implement a step-down correlative approach to synthesize knowledge obtained from the previous tasks to select one phase boundary, stressor, incubation time and organism (i.e., wildtype vs. mutant) for high resolution single-cell analyses of microbial activity and phase boundary physical architecture. The proposed work will employ cutting-edge techniques to understand fundamental mechanisms of microbial survival and contaminant transformation under environmental stresses faced in cold temperature environments such as the Arctic. These goals are highly relevant to the ARO Program as the Arctic contains vast natural resources to be discovered, and microbes are amidst the key players, being pivotal in all biogeochemical, cycles, impacting water quality, food production, alternative energy sources, and human and environmental health.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 08, 2022
- Source ID
- W911NF2210236
Entities
People
- Heidi Smith
Organizations
- Army Contracting Command
- Montana State University
- United States Army