Biology subjects

McCann, A.

Publications and source records attributed to McCann, A..

7 recordsLinked to original sources

bioRxiv2026

NeuroCaptain v2 - Interactive Three-Dimensional fNIRS Optode and Probe Montage Design Platform Based on Blender

SignificanceAccurate and reproducible optode placement is crucial for obtaining high-quality fNIRS data in both individual and group-level neuroimaging studies. Conventional optode/probe montage design tools usually transform a probe layout defined in 2D Cartesian space onto a 3D head surface using a mass-spring model. Such mechanical transformation, combined with the indirect mapping between the 2D probe definition and the 3D target space, can introduce placement variations across different head surfaces and subjects. AimWe introduce NeuroCaptain v2, an open-source Blender-based add-on designed to enable interactive, anatomically guided optode design, registration, and cortical sensitivity visualization for fNIRS head-cap and probe creation. ApproachNeuroCaptain v2 enables researchers to add, move, and edit fNIRS sources and detectors directly over a 3D head surface mesh, defining anchored optode positions, as well as setting the stiffness of the springs between adjacent optodes. It then utilizes Blenders built-in physical simulation engine to relax the initial probe layout to satisfy the mechanical constraints. With the built-in mesh-based Monte Carlo (MMC) and diffusion-solver Redbird, NeuroCaptain v2 computes and renders 3D sensitivity maps to guide iterative optode adjustment. The resulting 3D optode layout is stored in the form of barycentric coordinates defined in a 10-20 landmark mesh, enabling consistent probe transfer across different head models. ResultsWe demonstrate interactive 3D montage design, cross-head-atlas probe registration, and cortical sensitivity visualization across multiple head geometries. Registering a probe across seven neurodevelopmental head atlases, the proposed anatomical-coordinate approach yields a mean per-optode standard deviation of 2.29 mm, a roughly 74% reduction in cross-subject placement variability compared to 8.68 mm using a conventional 2D-to-3D registration. ConclusionsNeuroCaptain v2 provides a reproducible, fully open-source workflow for fNIRS probe montage design that facilitates anatomically guided probe development and cross-subject registration directly in a three-dimensional anatomical environment.

neuroscience↗

bioRxiv2025

Sequence and ionic requirements of pUG fold quadruplexes

Poly(UG) or "pUG" repeat RNA can fold into a left-handed parallel quadruplex, the pUG fold. The pUG fold directs the amplification of RNAi in C. elegans, and pUG sequences are abundant in eukaryotic transcriptomes. Here, we report the sequence and ionic requirements for pUG folding. The pUG fold requires 12 guanosines but has an otherwise flexible sequence requirement. The uridines can be substituted with other nucleotides, with some sequence variants folding better than pUG RNA. The GA repeat sequence (GA)12 also forms a pUG-like fold, albeit with lower thermodynamic stability than (GU)12. The pUG fold can tolerate multiple deoxyribose substitutions but does not fold when the backbone is entirely deoxyribose. It has a high affinity and specificity for potassium ions (K1/2 = 6 mM) and does not fold in sodium or ammonium ions. Addition of 2 mM Mg2+ does not further stabilize the pUG fold, and the polyamines spermine and spermidine slightly decrease its stability. Finally, the pUG fold is sensitive to surrounding sequence context and complementary flanking sequences can stabilize pUG folds, while other sequences can interfere with folding. These data expand our understanding of RNA folding and provide a basis for understanding and predicting pUG folds.

biochemistry↗

bioRxiv2024

Creating anatomically-derived, standardized, customizable, and three-dimensional printable head caps for functional neuroimaging

AbstractO_ST_ABSSignificanceC_ST_ABSConsistent and accurate probe placement is a crucial step towards enhancing the reproducibility of longitudinal and group-based functional neuroimaging studies. While the selection of headgear is central to these efforts, there does not currently exist a standardized design that can accommodate diverse probe configurations and experimental procedures. AimWe aim to provide the community with an open-source software pipeline for conveniently creating low-cost, 3-D printable neuroimaging head caps with anatomically significant landmarks integrated into the structure of the cap. ApproachWe utilize our advanced 3-D head mesh generation toolbox and 10-20 head landmark calculations to quickly convert a subjects anatomical scan or an atlas into a 3-D printable head cap model. The 3-D modeling environment of the open-source Blender platform permits advanced mesh processing features to customize the cap. The design process is streamlined into a Blender add-on named "NeuroCaptain". ResultsUsing the intuitive user interface, we create various head cap models using brain atlases, and share those with the community. The resulting mesh-based head cap designs are readily 3-D printable using off-the-shelf printers and filaments while accurately preserving the head topology and landmarks. ConclusionsThe methods developed in this work result in a widely accessible tool for community members to design, customize and fabricate caps that incorporate anatomically derived landmarks. This not only permits person-alized head cap designs to achieve improved accuracy, but also offers an open platform for the community to propose standardizable head caps to facilitate multi-centered data collection and sharing.

neuroscience↗

bioRxiv2022

Kinase Suppressor of RAS 1 (KSR1) maintains the transformed phenotype of BRAFV600E mutant human melanoma cells

KSR1 is a scaffolding protein for the RAS-RAF-MEK-ERK pathway, which is one of the most frequently altered pathways in human cancers. Previous results have shown that KSR1 has a critical role in mutant RAS mediated transformation. Here, we examined the role of KSR1 in mutant BRAF transformation. We used CRISPR/Cas9 to knock out KSR1 in a BRAFV600E transformed melanoma cell line. KSR1 loss produced a complex phenotype characterized by impaired proliferation, cell cycle defects, decreased transformation, decreased invasive migration, increased cellular senescence, and increased apoptosis. To decipher this phenotype, we used a combination of proteomic ERK substrate profiling, global protein expression profiling, and biochemical validation assays. The results suggest that KSR1 directs ERK to phosphorylate substrates that have a critical role in ensuring cell survival. The results further indicate that KSR1 loss induces the activation of p38 Mitogen-Activated Protein Kinase (MAPK) and subsequent cell cycle aberrations and senescence. In summary, KSR1 function plays a key role in oncogenic BRAF transformation.

cancer biology↗

bioRxiv2022

Grapevine leaf MALDI-MS imaging reveals the localisation of a putatively identified sucrose metabolite associated to Plasmopara viticola development

Despite well-established pathways and metabolites involved in grapevine-Plasmopara viticola interaction, information on the molecules involved in the first moments of pathogen contact with the leaf surface and their specific location is still missing. To understand and localise these molecules, we analysed grapevine leaf discs infected with P. viticola with MSI. Plant material preparation was optimised, and different matrices and solvents were tested. Our data shows that trichomes hamper matrix deposition and the ion signal. Results show that putatively identified sucrose presents a higher accumulation and a non-homogeneous distribution in the infected leaf discs in comparison with the controls. This accumulation was mainly on the veins, leading to the hypothesis that sucrose metabolism is being manipulated by the development structures of P. viticola. Up to our knowledge this is the first time that the localisation of a putatively identified sucrose metabolite was shown to be associated to P. viticola infection sites.

plant biology↗

bioRxiv2021

Chelator sensing and lipopeptide interplay mediates molecular interspecies interactions between soil bacilli and pseudomonads

AbstractSome bacterial species are important members of the rhizosphere microbiome and confer protection to the host plant against pathogens. However, our knowledge of the multitrophic interactions determining the ecological fitness of these biocontrol bacteria in their highly competitive natural niche is still limited. In this work, we investigated the molecular mechanisms underlying interactions between B. velezensis, considered as model plant-associated and beneficial species in the Bacillus genus, and Pseudomonas as a rhizosphere-dwelling competitor. Our data show that B. velezensis boosts its arsenal of specialized antibacterials upon the perception of the secondary siderophore enantio-pyochelin produced by phylogenetically distinct pseudomonads and some other genera. We postulate that B. velezensis has developed some chelator sensing systems to learn about the identity of its surrounding competitors. Illustrating the multifaceted molecular response of Bacillus, surfactin is another crucial component of the secondary metabolome mobilized in interbacteria competition. Its accumulation not only enhances motility but, unexpectedly, the lipopeptide also acts as a chemical trap that reduces the toxicity of other lipopeptides released by Pseudomonas challengers. This in turn favors the persistence of Bacillus populations upon competitive root colonization. Our work thus highlights new ecological roles for bacterial secondary metabolites acting as key drivers of social interactions.

microbiology↗

bioRxiv2019

Autochthonous faecal virome transplantation (FVT) reshapes the murine microbiome after antibiotic perturbation

BackgroundIt has become increasingly apparent that establishing and maintaining a complex and diverse gut microbiome is fundamental to human health. There are growing efforts to identify methods that can modulate and influence the microbiome, especially in individuals who due to disease or circumstance have experienced a disruption in their native microbiome. Faecal microbial transplantation (FMT) is one method that restores diversity to the microbiome of an individual by introducing microbes from a healthy donor. FMT introduces a complete microbiome into the recipient, including the bacteriome, archaeome, mycome and virome. In this study we investigated whether transplanting an autochthonous faecal virome consisting primarily of bacteriophages could impact a bacteriome disrupted by antibiotic treatment (Faecal Virome Transplantation; FVT).\n\nResultsFollowing disruption of the bacteriome by penicillin and streptomycin, test mice (n=8) received a bacteria free, faecal transplant, while Control mice (n=8) received a heated and nuclease treated control. The bacteriomes (as determined via 16S rRNA sequencing) of mice that received an FVT, in which bacteriophages predominate, separated from those of the Control mice as determined by principle co-ordinate analysis (PCoA), and contained differentially abundant taxa that reshaped the bacteriome profile such that it more closely resembled that of the pre-treatment mice. Similarly, metagenomic sequencing of the virome confirmed that the bacteriophages present in the gut of treatment and Control mice differed over time in both abundance and diversity, with transplanted phages seen to colonise the FVT mice.\n\nConclusionsAn autochthonous virome transplant impacts on the bacteriome and virome of mice following antibiotic treatment. The virome, consisting mainly of bacteriophages, reshapes the bacteriome such that it more closely resembles the pre-antibiotic state. To date, faecal transplants have largely focussed on transferring living microbes, but given that bacteriophage are inert biological entities incapable of colonising in the absence of a sensitive host they could form a viable alternative that may have fewer safety implications and that could be delivered as a robust formulation.

microbiology↗