scholarly journals Time-resolved analyses of elemental distribution and concentration in living plants: An example using manganese toxicity in cowpea leaves

2017 ◽  
Author(s):  
F. Pax C. Blamey ◽  
David J. Paterson ◽  
Adam Walsh ◽  
Nader Afshar ◽  
Brigid A. McKenna ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Plant Tissues ◽  
Elemental Distribution ◽  
List Type ◽  
Time Resolved ◽  
Living Plant ◽  
Xrf Scanning ◽  
Leaf Tissues ◽  
Changes Over Time

SummaryKnowledge of elemental distribution and concentration within plant tissues is crucial in the understanding of almost every process that occurs within plants. However, analytical limitations have hindered the microscopic determination of changes over time in the location and concentration of nutrients and contaminants in living plant tissues.We developed a novel method using synchrotron-based micro X-ray fluorescence (μ-XRF) that allows for laterally-resolved, multi-element, kinetic analyses of plant leaf tissues in vivo. To test the utility of this approach, we examined changes in the accumulation of Mn in unifoliate leaves of 7-d-old cowpea (Vigna unguiculata) plants grown for 48 h at 0.2 and 30 μM Mn in solution.Repeated μ-XRF scanning did not damage leaf tissues demonstrating the validity of the method. Exposure to 30 μM Mn for 48 h increased the initial number of small spots of localized high Mn and their concentration rose from 40 to 670 mg Mn kg-1 fresh mass. Extension of the two-dimensional μ-XRF scans to a three-dimensional geometry provided further assessment of Mn localization and concentration.This method shows the value of synchrotron-based μ-XRF analyses for time-resolved in vivo analysis of elemental dynamics in plant sciences.

scholarly journals Virtual Breast Quasi-static Elastography (VBQE)

2016 ◽  
Vol 39 (2) ◽  
pp. 108-125 ◽  
Author(s):  
David Rosen ◽  
Yu Wang ◽  
Jingfeng Jiang
Keyword(s):  
Relaxation Time ◽  
Three Dimensional ◽  
Primary Objective ◽  
Transfer Efficiency ◽  
External Compression ◽  
Time Resolved ◽  
Time Constants ◽  
Strain Measurements ◽  
Relaxation Time Constants

Viscoelasticity Imaging (VEI) has been proposed to measure relaxation time constants for characterization of in vivo breast lesions. In this technique, an external compression force on the tissue being imaged is maintained for a fixed period of time to induce strain creep. A sequence of ultrasound echo signals is then utilized to generate time-resolved strain measurements. Relaxation time constants can be obtained by fitting local time-resolved strain measurements to a viscoelastic tissue model (e.g., a modified Kevin-Voigt model). In this study, our primary objective is to quantitatively evaluate the contrast transfer efficiency (CTE) of VEI, which contains useful information regarding image interpretations. Using an open-source simulator for virtual breast quasi-static elastography (VBQE), we conducted a case study of contrast transfer efficiency of VEI. In multiple three-dimensional (3D) numerical breast phantoms containing various degrees of heterogeneity, finite element (FE) simulations in conjunction with quasi-linear viscoelastic constitutive tissue models were performed to mimic data acquisition of VEI under freehand scanning. Our results suggested that there were losses in CTE, and the losses could be as high as −18 dB. FE results also qualitatively corroborated clinical observations, for example, artifacts around tissue interfaces.

In vivo and in vitro validation of aortic flow quantification by time-resolved three-dimensional velocity-encoded MRI

2012 ◽  
Vol 28 (8) ◽  
pp. 1999-2008 ◽  
Author(s):  
Fabian Rengier ◽  
Michael Delles ◽  
Roland Unterhinninghofen ◽  
Sebastian Ley ◽  
Matthias Müller-Eschner ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Aortic Flow ◽  
Flow Quantification ◽  
Time Resolved

scholarly journals Three-dimensional in vivo analysis of water uptake and translocation in maize roots by fast neutron tomography

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Tötzke ◽  
Nikolay Kardjilov ◽  
André Hilger ◽  
Nicole Rudolph-Mohr ◽  
Ingo Manke ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Water Uptake ◽  
Three Dimensional ◽  
Root Systems ◽  
Neutron Tomography ◽  
Deuterated Water ◽  
Time Resolved ◽  
In Vivo Analysis ◽  
Uptake And Transport

AbstractRoot water uptake is an essential process for terrestrial plants that strongly affects the spatiotemporal distribution of water in vegetated soil. Fast neutron tomography is a recently established non-invasive imaging technique capable to capture the 3D architecture of root systems in situ and even allows for tracking of three-dimensional water flow in soil and roots. We present an in vivo analysis of local water uptake and transport by roots of soil-grown maize plants—for the first time measured in a three-dimensional time-resolved manner. Using deuterated water as tracer in infiltration experiments, we visualized soil imbibition, local root uptake, and tracked the transport of deuterated water throughout the fibrous root system for a day and night situation. This revealed significant differences in water transport between different root types. The primary root was the preferred water transport path in the 13-days-old plants while seminal roots of comparable size and length contributed little to plant water supply. The results underline the unique potential of fast neutron tomography to provide time-resolved 3D in vivo information on the water uptake and transport dynamics of plant root systems, thus contributing to a better understanding of the complex interactions of plant, soil and water.

scholarly journals Three-dimensional human axon tracts derived from cerebral organoids

2018 ◽  
Author(s):  
D. Kacy Cullen ◽  
Laura A. Struzyna ◽  
Dennis Jgamadze ◽  
Wisberty J. Gordián-Vélez ◽  
James Lim ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Neural Tissue ◽  
Cortical Layer ◽  
List Type ◽  
Brain Circuits ◽  
Novel Strategy ◽  
Cellular Phenotypes ◽  
The Brain

SummaryReestablishing cerebral connectivity is a critical part of restoring neuronal network integrity and brain function after trauma, stroke, and neurodegenerative diseases. Creating transplantable axon tracts in the laboratory is a novel strategy for overcoming the common barriers limiting axon regeneration in vivo, including growth-inhibiting factors and the limited outgrowth capacity of mature neurons in the brain. We describe the generation and phenotype of three-dimensional human axon tracts derived from cerebral organoid tissue. These centimeter-long constructs are encased in an agarose shell that permits physical manipulation and are composed of discrete cellular regions spanned by axon tracts and dendrites, mirroring the separation of grey and white matter in the brain. Features of cerebral cortex also are emulated, as evidenced by the presence of neurons with different cortical layer phenotypes. This engineered neural tissue has the translational potential to reconstruct brain circuits by physically replacing discrete cortical neuron populations as well as long-range axon tracts in the brain.eTOC BlurbRestoring axonal connectivity after brain damage is crucial for improving neurological and cognitive function. Cullen, et al. have generated anatomically inspired, three-dimensional human axon tracts projecting from cerebral organoids in a transplantable format that may facilitate the reconstruction of large-scale brain circuits.HighlightsA neural tissue engineering approach is applied to human cerebral organoids.Three-dimensional axon tracts are generated in a transplantable format.The growth characteristics of the engineered axons are examined.The cellular phenotypes of the organoid tissue and axons are characterized.

scholarly journals Toward in vivo-relevant hERG safety assessment and mitigation strategies based on relationships between non-equilibrium blocker binding, three-dimensional channel-blocker interactions, dynamic occupancy, dynamic exposure, and cellular arrhythmia

2020 ◽  
Author(s):  
Hongbin Wan ◽  
Gianluca Selvaggio ◽  
Robert A. Pearlstein
Keyword(s):  
Three Dimensional ◽  
Underlying Disease ◽  
Mitigation Strategies ◽  
Structural Basis ◽  
Head Group ◽  
List Type ◽  
Current Disruption ◽  
Binding Interface ◽  
Safety Parameters

AbstractThe human ether-a-go-go-related voltage-gated cardiac ion channel (commonly known as hERG) conducts the rapid outward repolarizing potassium current in cardiomyocytes (IKr). Inadvertent blockade of this channel by drug-like molecules represents a key challenge in pharmaceutical R&D due to frequent overlap between the structure-activity relationships of hERG and many primary targets. Building on our previous work, together with recent cryo-EM structures of hERG, we set about to better understand the energetic and structural basis of promiscuous blocker-hERG binding in the context of Biodynamics theory. We propose a two-step blocker binding process consisting of: Diffusion of a single fully solvated blocker copy into a large cavity lined by the intracellular cyclic nucleotide binding homology domain (the initial capture step). Occupation of this cavity is a necessary but insufficient condition for ion current disruption.Translocation of the captured blocker along the channel axis (the IKr disruption step), such that: The head group, consisting of a quasi-linear moiety, projects into the open pore, accompanied by partial de-solvation of the binding interface.One tail moiety packs along a kink between the S6 helix and proximal C-linker helix adjacent to the intra-cellular entrance of the pore, likewise accompanied by mutual de-solvation of the binding interface (noting that the association barrier is comprised largely of the total head + tail group de-solvation cost).Blockers containing a highly planar moiety that projects into a putative constriction zone within the closed channel become trapped upon closing, as do blockers terminating prior to this region.A single captured blocker molecule may associate and dissociate from the pore many times before exiting the CNBHD cavity.Lastly, we highlight possible flaws in the current hERG safety index (SI) and propose an alternate in vivo-relevant strategy factoring in: Benefit/risk.The predicted arrhythmogenic fractional hERG occupancy (based on action potential simulations of the undiseased human ventricular cardiomyocyte).Alteration of the safety threshold due to underlying disease.Risk of exposure escalation toward the predicted arrhythmic limit due to patient-to-patient pharmacokinetic variability, drug-drug interactions, overdose, and use for off-label indications in which the hERG safety parameters may differ from their on-label counterparts.

scholarly journals Snapping mechanics of the Venus flytrap (Dionaea muscipula)

2020 ◽  
Vol 117 (27) ◽  
pp. 16035-16042 ◽  
Author(s):  
Renate Sachse ◽  
Anna Westermeier ◽  
Max Mylo ◽  
Joey Nadasdi ◽  
Manfred Bischoff ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Image Correlation ◽  
Movement Behavior ◽  
Time Resolved ◽  
Venus Flytrap ◽  
In Vivo Experiments ◽  
Dionaea Muscipula ◽  
Tissue Changes ◽  
Plant Movement

The mechanical principles for fast snapping in the iconic Venus flytrap are not yet fully understood. In this study, we obtained time-resolved strain distributions via three-dimensional digital image correlation (DIC) for the outer and inner trap-lobe surfaces throughout the closing motion. In combination with finite element models, the various possible contributions of the trap tissue layers were investigated with respect to the trap’s movement behavior and the amount of strain required for snapping. Supported by in vivo experiments, we show that full trap turgescence is a mechanical–physiological prerequisite for successful (fast and geometrically correct) snapping, driven by differential tissue changes (swelling, shrinking, or no contribution). These are probably the result of the previous accumulation of internal hydrostatic pressure (prestress), which is released after trap triggering. Our research leads to an in-depth mechanical understanding of a complex plant movement incorporating various actuation principles.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Three-Dimensional Subcellular Organization of Hepatocytes in Intact Liver: Simultaneous Visualization of Cytoskeletal and Membrane Markers by Confocal Microscopy

1996 ◽  
Vol 54 ◽  
pp. 288-289
Author(s):  
Greg V. Martin ◽  
Ann L. Hubbard
Keyword(s):  
Three Dimensional ◽  
Integral Membrane Proteins ◽  
Polarized Secretion ◽  
Microscope Images ◽  
Computer Aided ◽  
Intracellular Organelles ◽  
Cytoskeletal Elements ◽  
Simultaneous Visualization

The microtubule (MT) cytoskeleton is necessary for many of the polarized functions of hepatocytes. Among the functions dependent on the MT-based cytoskeleton are polarized secretion of proteins, delivery of endocytosed material to lysosomes, and transcytosis of integral plasma membrane (PM) proteins. Although microtubules have been shown to be crucial to the establishment and maintenance of functional and structural polarization in the hepatocyte, little is known about the architecture of the hepatocyte MT cytoskeleton in vivo, particularly with regard to its relationship to PM domains and membranous organelles. Using an in situ extraction technique that preserves both microtubules and cellular membranes, we have developed a protocol for immunofluorescent co-localization of cytoskeletal elements and integral membrane proteins within 20 µm cryosections of fixed rat liver. Computer-aided 3D reconstruction of multi-spectral confocal microscope images was used to visualize the spatial relationships among the MT cytoskeleton, PM domains and intracellular organelles.

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