USAP-DC

Antarctica habitats are unlike any others found on the planet with extreme combined variations in cold, salinity, moisture content and light availability. Soils and sediments from the Antarctic McMurdo Dry Valley’s region harbor unique microorganisms that can cope with multiple extreme conditions, however, how extremophile microbes specifically function or respond to change in these extreme habitats is still largely unknown. This team is utilizing previously collected Antarctic McMurdo Dry Valleys (MDV) samples to evaluate differences in microbial extremophile function in response to changes in strong salinity gradients caused by warming temperatures. Comparative analyses of gene expression patterns and secondary metabolite production are being undertaken in lab-based microcosm studies with varying salinities. This work is helping to elucidate the genetic underpinnings for life in Antarctica and show how Antarctic biota evolve and adapt to a changing environment. Specifically, the work is showing how environmentally relevant changes in salinity will induce differential expression of secondary metabolites in isolates previously collected from the hypersaline Don Juan Pond in the western end of Wright Valley, Victoria Land in the Dry Valleys region. Transcriptomes of cell cultures under varying salinities are being sequenced and compared to determine significant changes to cellular metabolism, particularly secondary metabolic pathways. Additional previously collected sample types (soils, glacier ice, sediments, and brines) collected from a range of salinities are being used to refine methodologies for future field work and provide training opportunities for students. The program is designed to provide strong opportunities to integrate STEM research with undergraduate education, especially at Smith College, a predominantly undergraduate women’s institution. At least one graduate student and 4 undergraduates will be involved in the project, and some will participate in presenting results at international meetings. The program is also developing related curriculum in partnership with education specialists to be used with middle school students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Person	Role
Mikucki, Jill	Investigator and contact
Giddings, Lesley-Ann	Investigator

Antarctic Earth Sciences	Award # 2148730
Antarctic Organisms and Ecosystems	Award # 2148730

USAP-2148730_1

None in the Database

Repository	Title (link)	Format(s)	Status
GenBank	Massilia sp. DJPM01 Genome sequencing and assembly	Not Provided	exists
GenBank	Transcriptome of Shewanella sp. BF02_Schw		exists
Zenodo	Raw mass spectra of soluble metabolites from "Multi-technique characterization of iron reduction by an Antarctic Shewanella: an analog system for putative Martian biosignature identification"	CSV	exists

1. Samples, R., Mukoyama, R., Shaffer, J., Mikucki, J., & Giddings, L.-A. (2023). OpenASAP: An affordable 3D printed atmospheric solids analysis probe (ASAP) mass spectrometry system for direct analysis of solid and liquid samples. HardwareX, 16, e00490. (doi:10.1016/j.ohx.2023.e00490)
2. Shaffer, J.M., Giddings, L.A., Samples, R.M. and Mikucki, J.A., 2023. Genomic and phenotypic characterization of a red-pigmented strain of Massilia frigida isolated from an Antarctic microbial mat. Frontiers in Microbiology, 14, p.1156033. (doi:10.3389/fmicb.2023.1156033)
3. Shaffer, J.M., Sklute, E.C., Samples, R.M., Giddings, L.A., Jarratt, A., Mateos, K., Dyar, M.D., Lee, P.A., Livi, K.J. and Mikucki, J.A., 2025. Multi-technique characterization of iron reduction by an Antarctic Shewanella: an analog system for putative Martian biosignature identification. Applied and Environmental Microbiology, 91(8), pp.e02528-24. (doi:10.1128/aem.02528-24)