29 Sep 2023

Microbial Activity in Dust-Contaminated Antarctic Snow

Abstract: During weather events, particles can accumulate on the snow near the Pegasus ice and Phoenix compacted-snow Runways at the US McMurdo Station in Antarctica. The deposited particles melt into the surface, initially forming steep-sided holes, which can widen into patches of weak and rotten snow and ice. These changes negatively impact the ice and snow runways and snow roads trafficked by vehicles. To understand the importance of microbes on this process, we examined deposited dust particles and their microbial communities in snow samples collected near the runways. Snow samples were analyzed at the Cold Regions Research and Engineering Laboratory where we performed a respiration study to measure the microbial activity during a simulated melt, isolated microorganisms, examined particle-size distribution, and performed 16S rRNA gene sequencing. We measured higher levels of carbon dioxide production from a sample containing more dust than from a sample containing less dust, a finding consistent with viable dust-associated microbial communities. Additionally, eleven microorganisms were isolated and cultured from snow samples containing dust particles. While wind patterns and satellite images suggest that the deposited particles originate from nearby Black Island, comparisons of the particle size and chemical composition were inconclusive.

26 Sep 2023

Isolation and Characterization of Bacterial Isolates from Alaskan Permafrost for Synthetic Biology Applications

Abstract: Operations in the Artic and other cold regions require technologies that can perform reliably under extreme cold conditions. Permafrost and frozen soils harbor a wide range of microorganisms that have adapted to extremely low temperatures and have unique metabolic capabilities relevant to military operations and that could be exploited to develop biotechnologies optimized for cold environments. Cold-tolerant bacteria (psychrophiles and psychrotrophs) are critical to the development of synthetic biology technologies meant to work in cold environments like the Arctic. Using bacteria isolated from Alaskan permafrost, we applied an experimental pipeline to test the best candidates for use as biological platforms, or chassis, for low-temperature synthetic biology. Since synthetic biology constructs will perform only as well as their chassis, it is critical that circuits expected to perform under extreme cold conditions are housed in chassis that are adapted to those conditions. We identified one permafrost isolate, PTI8, related to Rhodococcus fascians, that is capable of growing from −1°C to at least 25°C and which we experimentally confirmed to uptake and express the broad host range plasmid pBTK519, suggesting PTI8 is a candidate for use as a novel cold-adapted chassis for synthetic biology.