Biology subjects

Gray, K.

Publications and source records attributed to Gray, K..

11 recordsLinked to original sources

bioRxiv2025

Chemical inhibition of asexual development leads to increased ultimate tensile strength in mycelial material.

This study investigates the chemical inhibition of asexual development in Aspergillus nidulans to enhance the mechanical properties of mycelial materials. We hypothesized that suppressing conidiation using the ornithine decarboxylase inhibitor -difluoromethylornithine (DFMO) would increase material strength by inhibiting asexual development, promoting denser hyphal packing. Mycelial materials were grown in DFMO concentrations (0, 0.05, 0.5, and 5 mM), and conidiation and ultimate tensile strength (UTS) were measured. Results showed a dose-dependent reduction in conidiation, with significant decreases at all DFMO levels (P [≤] 0.05). While lower DFMO concentrations (0.05 and 0.5 mM) did not significantly alter UTS, 5 mM DFMO treatment doubled the materials tensile strength compared to controls (P [≤] 0.05). Scanning electron microscopy confirmed reduced developmental structures in DFMO-treated samples, supporting the hypothesis. The non-linear relationship between conidiation suppression and strength improvement suggests additional mechanisms, such as hyphal morphology or cell wall changes, may contribute. These findings demonstrate that chemical modulation of fungal development can rationally tune mycelial material properties, offering a systematic approach for biomaterial engineering.

bioengineering↗

bioRxiv2024

Aspergillus nidulans cell wall integrity kinase, MpkA, impacts cellular phenotypes that alter mycelial-material mechanical properties

Mycelial materials are an emerging, natural material made from filamentous fungi that have the potential to replace unsustainable materials used in numerous commercial applications (e.g., packaging, textiles, construction). Efforts to change the mechanical properties of mycelial-materials have typically involved altering growth medium, processing approaches, or fungal species. Although these efforts have shown varying levels of success, all approaches have shown there is a strong correlation between phenotype (of both fungal mycelia and mycelial materials assembly) and resultant mechanical properties. We hypothesize that genetic means can be used to generate specific fungal phenotypes, leading to mycelial materials with specific mechanical properties. To begin to test this hypothesis, we used a mutant of the model filamentous fungus, Aspergillus nidulans, with a deletion of the last kinase in the cell wall integrity (CWI) signaling pathway, mpkA. We generated one set of mycelial materials from the {Delta}mpkA deletion mutant (A1404), and another from its isogenic parent (A1405; control). When subjected to tensile testing, and compared to material generated from the control, {Delta}mpkA material has similar elastic modulus, but significantly increased ultimate tensile strength, and strain at failure. When subjected to a fragmentation assay (i.e., resistance to shear-stress), the {Delta}mpkA material also had higher relative mechanical strength. To determine possible causes for this behavior, we carried out a comprehensive set of phenotype assessments focused on: three-dimensional structure, hyphal morphology, hyphal growth behaviors, and conidial development. We find, compared to the control, material generated from the {Delta}mpkA mutant manifests significantly less development, a modified cell wall composition, larger diameter hyphae, more total biomass, higher water capacity and more densely packed material, which all appear to impact the altered mechanical properties.

bioengineering↗

bioRxiv2024

Enhancing reproducibility and decentralization in single cell research with biocytometry

Biomedicine today is experiencing a shift towards decentralized data collection, which promises enhanced reproducibility and collaboration across diverse laboratory environments. This inter-laboratory study evaluates the performance of biocytometry, a method utilizing engineered bioparticles for enumerating cells based on their surface antigen patterns. In a decentralized framework, spanning 78 assays conducted by 30 users across 12 distinct laboratories, biocytometry consistently demonstrated significant statistical power in discriminating numbers of target cells at varying concentrations as low as 1 cell per 100,000 background cells. User skill levels varied from expert to beginner capturing a range of proficiencies. Measurement was performed in a decentralized environment without any instrument cross-calibration or advanced user training outside of a basic instruction manual. The results affirm biocytometry to be a viable solution for immunophenotyping applications demanding sensitivity as well as scalability and reproducibility and paves the way for decentralized analysis of rare cells in heterogeneous samples.

cell biology↗

bioRxiv2022

The VGNC: Expanding Standardized Vertebrate Gene Nomenclature

The Vertebrate Gene Nomenclature Committee (VGNC) was established in 2016 as a sister project to the HGNC (HUGO Gene Nomenclature Committee), to approve gene nomenclature in vertebrate species without an existing dedicated nomenclature committee. The VGNC aims to harmonize gene nomenclature across selected vertebrate species in line with human gene nomenclature, with orthologs assigned the same nomenclature where possible. This article presents an overview of the VGNC project and discussion of key findings resulting from this work to date. VGNC approved nomenclature is accessible at https://vertebrate.genenames.org, and is additionally displayed by the NCBI, Ensembl and UniProt databases.

genomics↗

bioRxiv2022

High-throughput, real-time monitoring of engineered skeletal muscle function using magnetic sensing

Engineered muscle tissues represent powerful tools for examining tissue level contractile properties of skeletal muscle. However, limitations in the throughput associated with standard analysis methods limit their utility for longitudinal study, high throughput drug screens, and disease modeling. Here we present a method for integrating 3D engineered skeletal muscles with a magnetic sensing system to facilitate non-invasive, longitudinal analysis of developing contraction kinetics. Using this platform, we show that engineered skeletal muscle tissues derived from both induced pluripotent stem cell and primary sources undergo improvements in contractile output over time in culture. We demonstrate how magnetic sensing of contractility can be employed for simultaneous assessment of multiple tissues subjected to different doses of known skeletal muscle inotropes as well as the stratification of healthy versus diseased functional profiles in normal and dystrophic muscle cells. Based on these data, this combined culture system and magnet-based contractility platform greatly broadens the potential for 3D engineered skeletal muscle tissues to impact the translation of novel therapies from the lab to the clinic.

bioengineering↗

bioRxiv2021

A programmable probiotic encapsulation system enhances therapeutic delivery in vivo

Recent advances in therapeutic modulation of human microbiota have driven new efforts to engineer living microbial medicines using synthetic biology. However, a long-standing challenge for live bacterial therapies is balancing the high dose required to achieve robust efficacy with the potential for sepsis. Here, we developed a genetically encoded microbial encapsulation system with tunable and dynamic expression of surface capsular polysaccharides to enhance therapeutic delivery. Following a synthetic small RNA knockdown screen of the capsular biosynthesis pathway, we constructed synthetic gene circuits that regulate bacterial encapsulation based on sensing the levels of environmental inducer, bacterial density, and blood pH. The induced encapsulation system enabled tunable immunogenicity and survivability of the probiotic Escherichia coli, resulting in increased maximum tolerated dose and enhanced efficacy in murine cancer models. Furthermore, triggering in situ encapsulation was found to increase microbial translocation between mouse tumors, leading to efficacy in distal tumors. The programmable encapsulation system demonstrates a new approach to control microbial therapeutic profiles in vivo using synthetic biology.

synthetic biology↗

bioRxiv2020

Clonal expansion of personalized anti-tumor T cells from circulation using tumor organoid-immune co-cultures

Tumor-specific cytotoxic T cells are effective tools for cancer immunotherapy, but the ability to generate them continues to be a challenge. Furthermore, there are no compelling approaches to empirically identify tumor-targeting T cells and T cell receptors by exploiting the multitude of antigens on tumor cell surfaces. Here, we use patients peripheral blood and autologous tumor organoids to enrich tumor-specific cytotoxic T cells with patient-specific killing mechanisms and a tissue-resident memory phenotype. We further demonstrate that these organoid-primed T (opT) cells undergo several orders of magnitude of clonal expansion and express T cells receptors and check-point proteins unique to each patient. Importantly, transferring the TCRs to heterologous T cells was sufficient to confer tumor recognition in a patient-specific manner. Thus, we report a patient-specific and antigen-agnostic platform for expansion of tumor-targeting T cells and identification of cancer-targeting TCRs from the peripheral blood of pancreatic cancer patients that can be exploited for immunotherapy applications.

cancer biology↗

bioRxiv2020

Metagenome-Assembled Genome Binning Methods Disproportionately Fail for Plasmids and Genomic Islands

Metagenomic methods are an important tool in the life sciences, as they enable simultaneous characterisation of all microbes in a community without time-consuming and bias-inducing culturing. Metagenome-assembled genome (MAG) binning methods have emerged as a promising approach to recover individual genomes from metagenomic data. However, MAG binning has not been well assessed for its ability to recover mobile genetic elements (MGEs), such as plasmids and genomic islands (GIs), that have very high clinical/agricultural/environmental importance. Certain antimicrobial resistance (AMR) genes and virulence factor (VF) genes are noted to be disproportionately associated with MGEs, making studying their transmission a public health priority. However, the variable copy number and sequence composition of MGEs relative to the majority of the host genome makes them potentially problematic for MAG binning methods. To systematically investigate this, we simulated a low-complexity metagenome comprising 30 GI-rich and plasmid-containing bacterial genomes. MAGs were then recovered using 12 current prediction pipelines and evaluated for recovery of MGE-associated AMR/VF genes. Here we show that while 82-94% of chromosomes could be correctly recovered and binned, only 38-44% of GIs were recovered and, even more notably, only 1-29% of plasmid sequences were found. Most strikingly, no plasmid-borne VF or AMR genes were recovered and within GIs, only between 0-45% of AMR or VF genes were identified. We conclude that short-read MAGs are largely ineffective for the analysis of mobile genes, including those of public-health importance like AMR and VF genes. We propose that microbiome researchers should instead primarily utilise unassembled short reads and/or long-read approaches to more accurately analyse metagenomic data

bioinformatics↗

bioRxiv2019

Multiplexed biosensors for precision bacteria tropism in vivo

The engineering of microbes spurs biotechnological innovations, but requires control mechanisms to confine growth within defined environments for translation. Here we engineer bacterial growth tropism to sense and grow in response to specified oxygen, pH, and lactate signatures. Coupling biosensors to drive essential gene expression reveals engineered bacterial localization within upper or lower gastrointestinal tract. Multiplexing biosensors in an AND logic-gate architecture reduced bacterial off-target colonization in vivo.

synthetic biology↗

bioRxiv2019

Small molecule inhibition of PIKFYVE kinase rescues gain- and loss-of-function C9ORF72 ALS/FTD disease processes in vivo

The most common known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a hexanucleotide repeat expansion (HRE) in C9ORF72 that contributes to neurodegeneration by both loss-of-function (decreased C9ORF72 protein levels) and gain-of-function (e.g. dipeptide repeat protein production) mechanisms. Although therapeutics targeting the gain-of-function mechanisms are in clinical development, it is unclear if these will be efficacious given the contribution of C9ORF72 loss-of-function processes to neurodegeneration. Moreover, there is a lack of therapeutic strategies for C9ORF72 ALS/FTD with demonstrated efficacy in vivo. Here, we show that small molecule inhibition of PIKFYVE kinase rescues both loss- and gain-of-function C9ORF72 disease mechanisms in vivo. We find that the reduction of C9ORF72 in mouse motor neurons leads to a decrease in early endosomes. In contrast, treatment with the PIKFYVE inhibitor apilimod increases the number of endosomes and lysosomes. We show that reduced C9ORF72 levels increases glutamate receptor levels in hippocampal neurons in mice, and that apilimod treatment rescues this excitotoxicity-related phenotype in vivo. Finally, we show that apilimod also alleviates the gain-of-function pathology induced by the C9ORF72 HRE by decreasing levels of dipeptide repeat proteins derived from both sense and antisense C9ORF72 transcripts in hippocampal neurons in vivo. Our data demonstrate the neuroprotective effect of PIKFYVE kinase inhibition in both gain- and loss-of-function murine models of C9ORF72 ALS/FTD.

neuroscience↗

bioRxiv2018

NanoMEA: a versatile platform for high-throughput analysis of structure-function relationships in human stem cell-derived excitable cells and tissues

Somatic cells derived from human pluripotent stem cell (hPSC) sources hold significant potential as a means to improve current in vitro screening assays. However, their inconsistent ability to recapitulate the structural and functional characteristics of native cells has raised questions regarding their ability to accurately predict the functional behavior of human tissues when exposed to chemical or pathological insults. In addition, the lack of cytoskeletal organization within conventional culture platforms prevents analysis of how structural changes in human tissues affect functional performance. Using cation-permeable hydrogels, we describe the production of multiwell nanotopographically-patterned microelectrode arrays (nanoMEAs) for studying the effect of structural organization on hPSC-derived cardiomyocyte and neuronal function in vitro. We demonstrate that nanoscale topographic substrate cues promote the development of more ordered cardiac and neuronal monolayers while simultaneously enhancing cytoskeletal organization, protein expression patterns, and electrophysiological function in these cells. We then show that these phenotypic improvements act to alter the sensitivity of hPSC-derived cardiomyocytes to treatment with arrhythmogenic and conduction-blocking compounds that target structural features of the cardiomyocyte. Similarly, we demonstrate that neuron sensitivity to synaptic blockers is increased when cells are maintained on nanotopographically-patterned Nafion surfaces. The improved structural and functional capacity of hPSC-derived cardiomyocyte and neuronal populations maintained on nanoMEAs may have important implications for improving the predictive capabilities of cell-based electrophysiological assays used in preclinical screening applications.

bioengineering↗