Protein sequencing remains a challenge for small samples. A sensitive sequencing technology will create the opportunity for single-cell proteomics and real-time screening for on-site medical diagnostics. We will use our expertise of single-molecule protein detection and material sciences to develop novel sequencing tools. In particular, we will use graphene mass sensors to measure the mass of proteins with sub-Dalton sensitivity. Utilizing this high sensitivity, we will measure the mass of protein fragments and identify the sequence of the fragments. We will also apply this method for detecting post-translational modifications of single proteins. Ultimately we aim to achieve sequencing of full-length proteins. This proof of concept will open the door to single-molecule protein sequencing and pave the road toward the development of a new, fast, and reliable diagnostic tool.

The world is characterized by an unequal distribution of resources. To cope, many organisms evolve symbiotic trade partnerships to exchange commodities they can provide at low cost, for resources more difficult to access. Such trade partnerships allow species to colonize extreme environments and survive resource fluctuations. While the ubiquity and importance of trade partnerships has been established, we do not understand the chemical, physical, and environmental stimuli mediating trade strategies, nor how organisms integrate this information to execute trade ‘decisions’. This is largely because of the lack of tools to quantify symbiotic trade across space and time.
Combining biophysics, fluid mechanics, network theory and evolution, we will develop techniques to track, quantify and predict trade strategies in symbiotic networks formed between plants and their arbuscular mycorrhizal fungal partners – a globally ubiquitous trade partnership fundamental to all terrestrial ecosystems. By visually monitoring the trade of nutrients tagged with fluorescent quantum-dot nanoparticles across scales - from within individual fungal hyphae up to complex plant-fungal networks - we will ask: (1) how do oscillatory flow patterns within fungal networks act to regulate fungal trade decisions; (2) can the fungus manipulate its chemistry and physical architecture to maximize nutrient transport and trade benefits; (3) can trade strategies be predicted by environmental stimuli; (4) what is the influence of the external microbiome on trade behaviors.
Using high-resolution video to track fluorescently tagged nutrients within hyphae, we will be the first to test how the fungal symbiont regulates internal flows to mediate trade. We will develop 2D and 3D time-lapse imaging of network topologies to test the factors driving the optimization of fungal transport routes. We will use transformed in-vitro root systems with precisely controlled nutrient landscapes to correlate specific trade strategies with environmental conditions. We will push the frontiers of tracking trade in whole plant mesocosms by growing plant-fungal networks on transparent farming film, characterizing how synthetic microbiomes affect trade strategies. By integrating the state of the art in imaging, fluid mechanics, and ecological manipulations, we will achieve a quantitative and predictive understanding of organismal trade.

Animal mitochondrial DNA (mtDNA) has a higher substitution rate than nuclear DNA, with the accumulation of mtDNA mutations being one of the hallmarks of ageing. This discrepancy in the rates of evolution is partially due to the lack of mismatch repair activities in the mitochondria. Octocorals – a group of cnidarians – have a reduced rate of mitochondrial evolution and encode a MUTS-like protein (mt-MutS) in their mtDNA. Previous analyses suggested that this enzyme was acquired from a virus and has been universally retained among octocoral taxa. Its function, however, remains unknown. The project will combine comparative, structural, and experimental approaches to investigate the function of mt-MutS and to test whether mt-MutS expression results in lower mutation rates in mtDNA and improve heath in ageing. Comparative analysis of octocoral mtDNA will be used to identify distinct mutation patterns among its lineages and correlate them with the changes in mt-MutS. Partial mt-MutS sequences will be used to identify clades with unusual or accelerated rates of mtDNA evolution for additional sampling. Site- and taxa-specific evolutionary rates in mt-MutS will be analyzed to infer functional and structural constraints and to optimize the choice of the mt-MutS for transgenesis. Ancestral sequences of mt-MutS for the nodes of interest will also be reconstructed and analyzed. A structure-function approach will be utilized for in vitro dissection of mt-MutS functions. The full-length proteins from several species and a reconstructed ancestral sequence will be tested for stability and for amenable structure determination. Isolated domains will also be used for high-resolution structural analysis by diverse biophysical techniques to probe molecular details of binding and nuclease activity for understanding and improving function. Finally, we will generate transgenic mice that express a mitochondrially-targeted version of this optimized mt-MutS enzyme to test its effects on mtDNA mutation rate. The transgene construct will be knocked-in to mice by directed Easi-CRISPR template repair or BAC-transgenesis. mtDNA mutation rate analyses in wildtype and mice with enhanced mitochondrial mutation rates will be undertaken. An ageing study on mice expressing mt-MutS will determine if enhanced mtDNA fidelity can positively affect organismal lifespan and healthspan.

Approximately 30% of mammalian genes code for transmembrane proteins, which comprise the majority of signal receptors and transducers. These functions are not solely encoded in protein structure, but are also regulated by the unique physicochemical environment of mammalian membranes. A key unmet challenge is to understand the interplay between the composition of membranes, their collective physical properties, and their resulting effect on protein function. The knowledge gap is especially apparent for mammalian neural tissue, whose membranes are highly enriched in omega-3 polyunsaturated fatty acids (PUFAs), which our bodies do not synthesize. This composition is central to neural function as evidenced by brain lipid alterations in numerous developmental, psychological, and neurodegenerative disorders; however the mechanistic relationships between the brain’s unique lipid composition and neurological functions are unknown. Major open questions are how neuronal function is influenced by the lipid content of the membranes that host neural signal transduction receptors, and how factors like diet and environment can influence those lipid compositions. Here, we assess the paradigm-shifting hypothesis that alterations of neuronal membrane lipid composition affect the signaling in the brain and contribute to the pathogenesis of neurological disorders. Particular emphasis is placed on the role of dietary lipids in modulating membrane composition, and the functional consequences thereof. Breakthroughs in understanding the central role of lipids will emerge from the project’s interdisciplinary crosstalk between detailed comprehensive lipidomics, molecular computer simulations, quantitative cellular biophysics, and molecular neurobiology. We focus on two parallel research streams: pattern-recognition receptors and G protein-coupled receptors, which are here used as representative systems to explore the regulation of neural receptors by lipids in a pipeline involving computational, synthetic, and natural model systems, as well as cultured cells and in vivo studies. As the influence of lipids on neuronal receptor function has so far been almost completely ignored, these studies will generate significant impact. Further, the modulation of membrane composition by diet may provide important translational insights and drug-free therapeutic strategies.

Optical nanostructures are highly organized composites of materials with varying refractive indices (e.g. keratin, melanin and air) that produce some of the brightest colors found in nature through coherent light scattering. How these tissues organise themselves at the nanometer scale to produce colors is poorly understood, despite its fundamental significance to developmental and evolutionary biology and potential to spark advances in the biomimetic design and "green" commercial manufacture of self-assembling optical materials.
We thus propose to use both transcriptomic, laser diffraction and microscopy-based tools of developmental biology to elucidate the mechanisms by which these nanostructures self-assemble in a subsample of birds (Class Aves), a group with incredibly diverse structural colors and mechanisms. Our working hypothesis is that iridescent colors form through depletion-attraction, phase separation and other self-assembly mechanisms. Because most developmental biology is done at larger size scales, testing these hypotheses will require the use and development of methods such as wet cell TEM and in situ laser diffraction analysis to adequately resolve nanometer-scale changes in developing tissue. We will then test these proposed mechanisms using biomimetic approaches that replicate natural conditions as closely as possible (e.g. at room temperature,at biological pH) using natural or semi-natural materials. Use of optical techniques including angle-resolved spectrophotometry and microspectrophotometry will enable us to compare these properties between the natural and synthetic versions. This approach will enable us to not only experimentally test modes of development but also generate and test new materials and/or processes to produce them.
There are three highly innovative aspects to this proposal. First, it attempts to unlock the developmental pathways producing nanostructured tissues. This is a long-standing question with few answers thus far. Second, it uses biomimicry in novel ways to test developmental hypotheses and pushes the technical boundaries of developmental biology by focusing on nanometer-scale organisation of tissues. Finally, the use of biologically realistic chemistry in our biomimetic approaches is a huge leap forward in this field where most work is done at high temperature or with non-biocompatible materials. This work will therefore significantly advance both our fundamental understanding of these materials and the tools to study them and other nanoscale materials.