Biology subjects

Grevesse, T.

Publications and source records attributed to Grevesse, T..

3 recordsLinked to original sources

bioRxiv2026

Metagenomic Discovery of Neutral Lipid Metabolism Pathways in the Arctic Ocean Microbiomes Suggests a Potential New Role in Survival and Oceanic Carbon Cycling

The Arctic Ocean microbiomes experience extreme seasonal fluctuations in light, nutrient availability, and organic carbon supply. In this environment, neutral lipid storage may provide a key survival strategy. Here, we investigated the diversity, distribution, and ecological role of neutral lipid metabolism in Arctic microbiomes using metagenome-resolved analyses and global ocean comparisons. Arctic photic-zone microbiomes were strongly enriched in triacylglycerol (TAG) biosynthesis genes relative to other oceans, primarily due to picoeukaryotic phytoplankton, including the ecologically dominant Micromonas and Bathycoccus. In contrast, prokaryotic communities exhibited diverse TAG-degrading taxa and fatty acid transport systems, supporting a previously unrecognized lipotrophic bacterial guild exploiting phytoplankton-derived lipids as carbon and energy sources. Genome-resolved analyses further revealed distinct bacterial lipid-storage strategies: TAG-producing taxa preferentially encoded fatty acid uptake and carbohydrate utilization pathways, whereas polyhydroxyalkanoate-producing taxa were associated with aromatic compound degradation, linking terrestrial organic matter to lipid storage. Our results expand the known diversity of marine microbes capable of neutral lipid metabolism and identify microbial lipid cycling as a previously overlooked component of the Arctic carbon cycle. We propose that neutral lipid storage and turnover support microbial survival through the polar night while enhancing carbon transfer within Arctic microbial food webs under ongoing climate change.

microbiology↗

bioRxiv2022

Degradation pathways for organic matter of terrestrial origin are widespread and expressed in Arctic Ocean microbiomes

BackgroundThe Arctic Ocean receives massive freshwater input and a correspondingly large amount of humic-rich organic matter of terrestrial origin. Global warming, permafrost melt, and a changing hydrological cycle will contribute to an intensification of terrestrial organic matter release to the Arctic Ocean. Although considered recalcitrant to degradation due to complex aromatic structures, humic substances can serve as substrate for microbial growth in terrestrial environments. However, the capacity of marine microbiomes to process aromatic-rich humic substances, and how this processing may contribute to carbon and nutrient cycling in a changing Arctic Ocean, is relatively unexplored. Here, we used a combination of metagenomics and metatranscriptomics to assess the prevalence and diversity of metabolic pathways and bacterial taxa involved in aromatic compound degradation in the salinity-stratified summer waters of the Canada Basin in the western Arctic Ocean. ResultsCommunity-scale meta-omics profiling revealed that 22 complete pathways for processing aromatic compounds were present and expressed in the Canada Basin, including those for aromatic ring fission and upstream funnelling pathways to access diverse aromatic compounds of terrestrial origin. A phylogenetically diverse set of functional marker genes and transcripts were associated with fluorescent dissolved organic matter, a component of which is of terrestrial origin. Pathways were common throughout global ocean microbiomes, but were more abundant in the Canada Basin. Genome-resolved analyses identified 12 clades of Alphaproteobacteria, including Rhodospirillales, as central contributors to aromatic compound processing. These genomes were mostly restricted in their biogeographical distribution to the Arctic Ocean, and were enriched in aromatic compound processing genes compared to their closest relatives from other oceans. ConclusionOverall, the detection of a phylogenetically diverse set of genes and transcripts implicated in aromatic compound processing supports the view that Arctic Ocean microbiomes have the capacity to metabolize humic substances of terrestrial origin. In addition, the demonstration that bacterial genomes replete with aromatic compound degradation genes exhibit a limited distribution outside of the Arctic Ocean suggests that processing humic substances is an adaptive trait of the Arctic Ocean microbiome. Future increases in terrestrial organic matter input to the Arctic Ocean may increase the prominence of aromatic compound processing bacteria and their contribution to Arctic carbon and nutrient cycles.

microbiology↗

bioRxiv2019

A robotic platform for fluidically-linked human body-on-chips experimentation

Here we describe of an Interrogator instrument that uses liquid-handling robotics, a custom software package, and an integrated mobile microscope to enable automated culture, perfusion, medium addition, fluidic linking, sample collection, and in situ microscopic imaging of up to 10 Organ Chips inside a standard tissue culture incubator. The automated Interrogator platform maintained the viability and organ-specific functions of 8 different vascularized, 2-channel, Organ Chips (intestine, liver, kidney, heart, lung, skin, blood-brain barrier (BBB), and brain) for 3 weeks in culture when fluidically coupled through their endothelium-lined vascular channels using a common blood substitute medium. When an inulin tracer was perfused through the multi-organ Human Body-on-Chips (HuBoC) fluidic network, quantitative distributions of this tracer could be accurately predicted using a physiologically-based multi-compartmental reduced order (MCRO) in silico model of the experimental system derived from first principles. This automated culture platform enables non-invasive imaging of cells within human Organ Chips and repeated sampling of both the vascular and interstitial compartments without compromising fluidic coupling, which should facilitate future HuBoc studies and pharmacokinetics (PK) analysis in vitro.

bioengineering↗