Biology subjects

Gray, I.

Publications and source records attributed to Gray, I..

4 recordsLinked to original sources

bioRxiv2026

Direct electrochemical cortisol detection via transition-resolved interrogation at a defect-engineered graphene interface

Continuous tracking of cortisol is central to understanding human stress physiology, yet direct electrochemical detection without biological receptors remains challenging despite its promise for stable and dynamic sensing. Electrochemical reduction of cortisol typically occurs at highly negative potentials, where parasitic interfacial currents, hydrogen evolution, and substantial capacitive background overlap with the cortisol reduction signal, preventing accurate quantification. We overcome this barrier through an integrated material-measurement strategy combining a defect-engineered graphene interface with a transition-resolved interrogation (TRI) measurement strategy. First, we engineered polybenzimidazole-derived laser-induced graphene containing nitrogen-rich defects while suppressing oxygen-derived functionalities which reduced parasitic background currents within the same cathodic potential regime. Next, we designed TRI to leverage differences in the time-dependent evolution of overlapping cathodic processes to isolate a localized cortisol-associated electrochemical reduction transition. Derivative-domain projection coupled with background estimation enables its reliable quantification. This integrated sensing architecture enables sensitive, selective, and dynamic cortisol detection in both artificial and biological interstitial fluids at low nanomolar concentrations. The response remains reproducible across physiologically relevant variations in pH, ionic strength, temperature, and repeated cycling. Together, these capabilities provide a basis for continuous electrochemical cortisol monitoring for future study of stress physiology.

bioengineering↗

bioRxiv2026

A single-strain dropout screen reveals mechanistic links between microbial ecology and metabolism

The complexity of the gut microbiome has made it challenging to define the role of individual species in community-level function. Here, we constructed 56 single-strain dropout variants of a defined 118-member community and used each one to colonize a group of germ-free mice. In many cases, removing a single strain triggered a large reordering of a small group of species, which in turn altered the communitys metabolic output. En bloc removal of the eight-strain acetogen compartment markedly reduced acetate production and caused intestinal H2 accumulation and bloating; a specific subset of four acetogens was sufficient to relieve bloating and restore acetate production. Together, these data show that small disturbances in community composition can trigger a confined ecological reorganization with a large chemical phenotype, and they reveal novel strategies for engineering communities with altered metabolic output.

microbiology↗

bioRxiv2025

Efficient in vivo mammalian neuron editing using peptide-mediated CRISPR enzyme delivery

CRISPR-mediated genome editing of the central nervous system (CNS) has the potential to revolutionize the treatment of neurological disorders, including neurodegenerative disorders such as Huntingtons disease (HD). However, the development of CRISPR therapeutics for the CNS has been hindered by challenges associated with delivery, specifically the lack of a clinically compatible, non-viral delivery technology facilitating genome editing of neurons in vivo. For most indications, two key obstacles must be overcome before therapeutic genome editing of the brain is feasible: non-toxic intracellular delivery of CRISPR cargo into neurons and establishment of strategies enabling targeted brain regions to be edited efficiently. While viral vectors have shown promise in pre-clinical models, non-viral approaches present distinct advantages: ease of manufacture as well as the transient presence of CRISPR machinery, which tempers risks of genotoxicity and immunogenicity. Peptide-enabled ribonucleoprotein (RNP) delivery of CRISPR (PERC) has emerged as a promising non-viral delivery strategy for CRISPR enzymes with initial use in primary human immune cells. In this study, we report the development of Neuro-PERC, a streamlined and optimized approach for in vivo editing of mammalian neurons. Administration of Neuro-PERC reagents via convection-enhanced delivery (CED) mediated efficient and well-tolerated neuronal genome editing. Neuro-PERC enabled robust neuronal editing in the brain of both small and large animal reporter models, and increased survival in a severe murine model of Huntingtons disease. These results establish CED-administered Neuro-PERC as a candidate delivery technology to hasten clinical translation of CRISPR-based therapies for diseases of the CNS. SummaryNeuro-PERC, a peptide-mediated CRISPR enzyme delivery technology, enables efficient in vivo mammalian neuronal editing in the brain of mice and pigs, extending survival in a murine model of Huntingtons disease when administered via convection-enhanced delivery (CED).

neuroscience↗

bioRxiv2023

Evolutionary genomics identifies host-directed therapeutics to treat intracellular bacterial infections

Obligate intracellular bacteria shed essential biosynthetic pathways during their evolution towards host dependency, providing an opportunity for host-directed therapeutics. Using Rickettsiaceae as a model, we employed a novel computational pipeline called PoMeLo to systematically compare this cytosolic family of bacteria to the related Anaplasmataceae, which reside in a membrane-bound vacuole in the host cell. We identified 20 metabolic pathways that have been lost since the divergence of Anaplasmataceae and Rickettsiaceae, corresponding to the latters change to a cytosolic niche. We hypothesized that drug inhibition of these host metabolic pathways would reduce the levels of metabolites available to the bacteria, thereby inhibiting bacterial growth. We tested 22 commercially available inhibitors for 14 of the identified pathways and found that the majority (59%) reduced bacterial growth at concentrations that did not induce host cell cytotoxicity. Of these, 5 inhibitors with an IC50 under 5 M were tested to determine whether their mode of inhibition was bactericidal or bacteriostatic. Both mycophenolate mofetil, an inhibitor of inosine-5-monophosphate dehydrogenase in the purine biosynthesis pathway, and roseoflavin, an analog of riboflavin, displayed bactericidal activity. A complementary unbiased mass spectrometry-based metabolomics approach identified 14 pathways impacted by Rickettsia infection based on alterations in metabolite levels. Strikingly, 11 of these (79%) overlapped with those identified by our computational predictions. These in vitro validation studies support the feasibility of a novel evolutionary genomics-guided approach for host-directed antibiotic drug development against obligate pathogens. ImportanceMany pathogens have evolved to acquire essential metabolites from their host cell, while in turn shedding their own biosynthetic capacities. This leads to an interesting dilemma: on one hand, reduced genomes allow pathogens to save energy and replicate more quickly, while on the other hand, they become more dependent on the host cell for survival. This vulnerability can be exploited by identifying and therapeutically inhibiting the host pathways that are essential for pathogen survival. The significance of our research is in predicting the precise pathways lost during a pathogens evolutionary adaptation to parasitism and validating these predictions through targeted in vitro growth assays and an unbiased metabolomic survey of the host-pathogen interface.

genomics↗