Grants recently awarded to the Glass lab:

Methane from Nontraditional Abiotic Sources and Potential for False Positive Biosignatures
Rescorp Scialog, 2021-2022
PIs: Jennifer Glass, Edward Kite, Smadar Naoz
Students: Camille Butkus
Given the great emphasis on methane as a biosignature gas, our goal is to assess alternative abiotic methane origin pathways beyond those that have been widely discussed to eliminate false positives more robustly in life detection on exoplanets. We will explore the implications of unexplored diversity in both redox state and carbon abundance to produce methane false positives.
Microbial interactions with methane clathrate: Implications for habitability of icy moons
NASA Exobiology
PI: Jennifer Glass
Co-Is: Sheng Dai, Raquel Lieberman, Loren Williams
Postdocs/students: Abigail Johnson, Dustin Huard, Manlin Xu
Methane clathrates are likely widespread in our solar system, including on icy moons and the Martian subsurface, yet their habitability remains virtually unstudied. The proposed research will investigate interactions between microbial proteins and methane clathrates. Specifically, the proposed work will test the hypothesis that microbes living in methane clathrates encode proteins optimized for clathrate binding, and that these “clathrate binding proteins” (CBPs) alter the structure, thermodynamics and kinetics of methane clathrates. Our results will contribute to understanding biosignatures of microbial colonization of methane clathrates on Earth and potentially elsewhere in our solar system. The proposed research will: (i) heterologously express, purify, assay, and biophysically characterize candidate CBPs; (ii) quantify the effects of CBPs on methane clathrate thermodynamics and kinetics of formation and decomposition in laboratory experiments with pressurized vessels; (iii) solve crystal structures of select CBPs and characterize static interactions with water molecules; (iv) use high-throughput homology modeling, molecular dynamics, and other computations to characterize structures and dynamics of CBPs; (v) create a public database of CBPs.
Characterization of microbes mediating anaerobic oxidation of methane  coupled to iron reduction from an ancient ocean analogue
NASA Exobiology
PI: Jennifer Glass
PhD student: Marcus Bray Postdoc: Nadia Szeinbaum, Jieying Wu
Early microbial life evolved in a biosphere rich in iron and methane, and low in sulfate and oxygen. Prior to the Great Oxidation Event (2.4 billion years ago), the major sink for methane is postulated to have been microbial anaerobic oxidation of methane (AOM). Microbes that coupled AOM to Fe(III) reduction (hereafter abbreviated Fe-AOM) may have comprised a significant portion of biomass in the anoxic ocean due to the scarcity of alternative electron acceptors (i.e. sulfate, nitrate). Recently, geochemical evidence for Fe-AOM has been discovered in numerous modern environments. However the microorganisms catalyzing iron-dependent AOM remain completely unknown. We propose to enrich, isolate and characterize these enigmatic microbes using existing enrichment cultures from ferruginous Lake Matano, Indonesia, an Archean ocean analogue.
Functional gene diversity and expression in deep subsurface methane-hydrate bearing sediments
PI: Jennifer Glass
Postdoc: Cecilia Batmalle Kretz
Methane is a product of and substrate for microbial metabolisms in the deep subsurface, but little is known about microbial metabolisms in deep methane hydrate-bearing sediments. We analyzed microbial community diversity and function in subsurface sediments beneath Hydrate Ridge, offshore Oregon (ODP Leg 204 Site 1244). We targeted four geochemically distinct sediment zones: near surface (2 mbsf), sulfate-methane transition zone (4 and 8 mbsf), iron-manganese reduction zone (18 and 20 mbsf) and deep subsurface (35 and 69 mbsf). Reactive iron increased with depth from 2 mbsf (0.4%) to 21 mbsf (1.1%), where dissolved iron and methane concentrations also peaked. The proportion of archaeal sequences decreased with depth, with deeper sediments dominated by Atribacteria and Chloroflexi. There was a resurgence of uncultivated archaeal groups (10% SAGMEG-1 and 16% MBGB) in the iron-manganese reduction zone. Illumina HiSeq metagenomic sequencing of genomic DNA subjected to single cell multiple displacement amplification resulted in 336 million total and 33.7 million coding reads. The taxonomic affiliations of metagenomic sequences corroborated the trend of increasing Atribacteria genes with depth, but a higher percentage of Chloroflexi sequences. ESOM assembly yielded two Atribacteria genomes of ≤5% contamination from 2 vs. 69 mbsf with 55% and 37% completeness, respectively. Genes for amino acid transport and peptide fermentation, as well as Ni-Fe hydrogenases and the Wood-Ljungdahl carbon fixation pathway, were present. All data are available at