Biology subjects

Husted, S.

Publications and source records attributed to Husted, S..

5 recordsLinked to original sources

bioRxiv2025

Achieving Micrometer-Scale 4D X-ray tomography of Living Leaf Tissue in the Laboratory

A methodology for achieving micrometer-scale 4D X-ray lab microscopy of living leaf tissue was developed to overcome challenges associated with delicate tissues, radiation damage, and motion artifacts during in vivo imaging. The study focused on optimizing laboratory based X-ray micro-computed tomography (microCT) parameters to balance high-resolution imaging with minimized physiological stress and radiation dose quantification. Assessing the dose-safe imaging window required comparing vertical and horizontal leaf mounting setups. Results demonstrated that the horizontal setup provided greater stability, preventing tissue degradation and maintaining sample viability during continuous acquisitions lasting up to 22 hours ([~]15600 Gy). MicroCT capacities were clearly able to resolve microstructures at the cellular level, achieving a pixel size down to 1 {micro}m. Furthermore, this optimized methodology confirmed the ability to track the spatiotemporal dynamics of applied compounds such as iohexol and aggregated nanoparticles within the leaf tissue. This work establishes that accessible laboratory based microCT enables the in vivo 4D monitoring of anatomical and physiological changes in living plants.

plant biology↗

bioRxiv2025

Foliar Application of Polymer-coated Manganese Dioxide Nanoparticles: Mechanisms of Uptake and Metabolic Responses in Manganese Deficient Barley

The application of nanotechnology in plant science is unlocking innovative approaches to enhance nutrient use efficiency in crops, particularly through foliar fertilization. This study demonstrates that colloidally stable, pH-responsive polyacrylic acid (PAA)-coated manganese dioxide (MnO2) nanoparticles (nPAA-MnO2) can be designed to significantly restore key metabolic functionalities in manganese (Mn)-deficient barley (Hordeum vulgare) within a few days. Using a combination of advanced bioimaging techniques - including confocal laser scanning microscopy (CLSM), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and X-ray nano-computed tomography (nano-CT), we mapped the uptake and distribution pathways of nPAA-MnO2 compared to ionic Mn. While soluble Mn2+ ions primarily enter through hydrophilic cuticular pores, nPAA-MnO2 penetrates leaves via stomata, facilitated by the application of an organosilicone surfactant and glycerol to enhance wetting and hydraulic activation of stomatal pores. Within a few hours, nPAA-MnO2 accumulated in the sub-stomatal cavity and mesophyll apoplast, gradually releasing bioavailable Mn ions in the acidic apoplast environment. Moreover, labeling experiments with tracer ions revealed nPAA-MnO2 hot-spots around the vascular bundles and a limited but significant basipetal translocation of intact nanoparticles out of the foliar application zone, a pivotal step towards converting immobile nutrients such as Mn into mobile ones. Importantly, and unlike ionic Mn solutions, nPAA-MnO2 could be applied at high doses without causing leaf scorching and cytotoxicity, paving the way for more sustainable and efficient foliar fertilization practices. These novel aspects of nanoparticle uptake, translocation, and assimilation underscores the potential of nanotechnology to address nutrient mobility challenges in agriculture, representing an important contribution to the green transition of modern crop production.

plant biology↗

bioRxiv2025

3D X-ray microscopy lights up nanoparticles in plants

The discovery of novel plant fertilization strategies heavily relies on our capabilities to probe physiological processes in living plants with sub-cellular precision. State-of-the-art microscopy techniques are in general limited to surface investigation or they require elaborated tissue preparation and often destruction. X-ray microscopy has the potential to resolve some of these limitations by generating micro-to nanometer-scale 3D images deep into the tissue. We introduce experimental designs and the quantitative analysis methodologies, pioneering nanoscale ({approx}150 nm resolution) in-vivo 3D microscopy of plant tissue. We show the first direct in-vivo visualization of foliar-applied untagged nanoparticulate fertilizers deep under the leaf surface, not accessible by other microscopy methods. Ultimately, our approach provides the means for a direct observation of nanoparticle transport and dissolution in living plant tissue, a step critical for developing sustainable plant fertilization approaches.

plant biology↗

bioRxiv2023

MCAK Inhibitors Induce Aneuploidy in Triple Negative Breast Cancer Models

Standard of care for triple negative breast cancer (TNBC) involves the use of microtubule poisons like paclitaxel, which are proposed to work by inducing lethal levels of aneuploidy in tumor cells. While these drugs are initially effective in treating cancer, dose-limiting peripheral neuropathies are common. Unfortunately, patients often relapse with drug resistant tumors. Identifying agents against targets that limit aneuploidy may be a valuable approach for therapeutic development. One potential target is the microtubule depolymerizing kinesin, MCAK, which limits aneuploidy by regulating microtubule dynamics during mitosis. Using publicly available datasets, we found that MCAK is upregulated in triple negative breast cancer and is associated with poorer prognoses. Knockdown of MCAK in tumor-derived cell lines caused a two- to five-fold reduction in the IC50 for paclitaxel, without affecting normal cells. Using FRET and image-based assays, we screened compounds from the ChemBridge 50k library and discovered three putative MCAK inhibitors. These compounds reproduced the aneuploidy-inducing phenotype of MCAK loss, reduced clonogenic survival of TNBC cells regardless of taxane-resistance, and the most potent of the three, C4, sensitized TNBC cells to paclitaxel. Collectively, our work shows promise that MCAK may serve as both a biomarker of prognosis and as a therapeutic target. Simple SummaryTriple negative breast cancer (TNBC) is the most lethal breast cancer subtype with few treatment options available. Standard of care for TNBC involves the use of taxanes, which are initially effective, but dose limiting toxicities are common, and patients often relapse with resistant tumors. Specific drugs that produce taxane-like effects may be able to improve patient quality of life and prognosis. In this study we identify three novel inhibitors of the Kinesin-13 MCAK. MCAK inhibition induces aneuploidy; similar to cells treated with taxanes. We demonstrate that MCAK is upregulated in TNBC and is associated with poorer prognoses. These MCAK inhibitors reduce the clonogenic survival of TNBC cells, and the most potent of the three inhibitors, C4, sensitizes TNBC cells to taxanes, similar to the effects of MCAK knockdown. This work will expand the field of precision medicine to include aneuploidy-inducing drugs that have the potential to improve patient outcomes.

cancer biology↗

bioRxiv2022

Endodermal suberin deposition restricts potassium leakage from roots

O_LIThe endodermis is a checkpoint for ions and water escaping or entering the root. It has been hypothesized that suberin acts as a physical barrier preventing potassium (K) leakage from the stele during translocation, but attempts to support this idea has yielded contradictory results. C_LIO_LIWe developed a Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) based element bioimaging method to study K leakage from roots with different suberin deposition, where we show that cesium (Cs) is an excellent tracer for K. C_LIO_LIElement bioimaging of roots and total shoot concentrations from various Arabidopsis thaliana mutants all showed a positive relationship between suberin deposition and K translocation efficiency. In addition, images from the fully suberized barley (Hordeum vulgare) seminal roots revealed a strongly reduced K leakage compared to less suberized root zones. C_LIO_LINodal roots form a scattered deposition of suberin towards the phloem in the mature root zone. This incomplete suberin deposition also restrict K leakage efficiently. C_LIO_LICollectively, our findings provide experimental evidence that suberin act as a barrier for K leakage upon root-to-shoot translocation by restricting K movement over the endodermis from the stele to cortex. C_LI

plant biology↗