scholarly journals Mechanical Causation of Biological Structure: Productive Pulls Produce Persistent Filaments in a Human Fibroblast Model of Matrix Development

2021 ◽  
Author(s):  
Alexandra A. Silverman ◽  
Seyed Mohammad Siadat ◽  
Jason D. Olszewski ◽  
Jeffrey W. Ruberti
Keyword(s):  
Cellular Level ◽  
Human Cornea ◽  
Corneal Fibroblast ◽  
Average Maximum ◽  
Extensional Strain ◽  
Collagenous Stroma ◽  
Cell Kinematics ◽  
Temporal And Spatial ◽  
Insight Into ◽  
Fibroblast Model

During development, mesenchymal cells direct the elaboration of extracellular matrix that shapes the initial animal bauplan which subsequently grows to produce mechanically-competent structure. To gain insight into the processes that initiate matrix formation at the cellular level, high temporal and spatial resolution videos were obtained from a primary human corneal fibroblast (PHCF) cell culture system known to produce an organized, collagenous stroma similar to a human cornea. The images were taken over a 4-day period prior to culture confluency which permitted a clear view of the cell kinematics and any elaborated filaments. The movies reveal an active cellular system in which the PHCFs execute five types of high-velocity and high extensional strain-rate 'pulls' that produce persistent filaments. In four of the pull types, average maximum strain rates (~0.1-0.33s-1) were adequate to induce aggregation and/or crystallization in crowded biopolymer systems. The results demonstrate that PHCFs have the capacity to mechanically induce the formation of biopolymer structures intercellularly and in the path of force.

Nanoparticle-plasma Membrane Interactions: Thermodynamics, Toxicity and Cellular Response

2020 ◽  
Vol 27 (20) ◽  
pp. 3330-3345
Author(s):  
Ana G. Rodríguez-Hernández ◽  
Rafael Vazquez-Duhalt ◽  
Alejandro Huerta-Saquero
Keyword(s):  
Gene Expression ◽  
Immune Responses ◽  
Cellular Response ◽  
Cellular Level ◽  
Membrane Interactions ◽  
Daily Lives ◽  
Cellular Physiology ◽  
Associated Proteins ◽  
First Contact ◽  
Insight Into

Nanomaterials have become part of our daily lives, particularly nanoparticles contained in food, water, cosmetics, additives and textiles. Nanoparticles interact with organisms at the cellular level. The cell membrane is the first protective barrier against the potential toxic effect of nanoparticles. This first contact, including the interaction between the cell membranes -and associated proteins- and the nanoparticles is critically reviewed here. Nanoparticles, depending on their toxicity, can cause cellular physiology alterations, such as a disruption in cell signaling or changes in gene expression and they can trigger immune responses and even apoptosis. Additionally, the fundamental thermodynamics behind the nanoparticle-membrane and nanoparticle-proteins-membrane interactions are discussed. The analysis is intended to increase our insight into the mechanisms involved in these interactions. Finally, consequences are reviewed and discussed.

scholarly journals RECQL, a Member of the RecQ Family of DNA Helicases, Suppresses Chromosomal Instability

2006 ◽  
Vol 27 (5) ◽  
pp. 1784-1794 ◽  
Author(s):  
Sudha Sharma ◽  
Deborah J. Stumpo ◽  
Adayabalam S. Balajee ◽  
Cheryl B. Bock ◽  
Peter M. Lansdorp ◽  
...  
Keyword(s):  
Cellular Level ◽  
Sister Chromatid Exchanges ◽  
Cellular Phenotype ◽  
Chromosomal Breakage ◽  
Dna Helicases ◽  
Phenotypic Differences ◽  
Cytogenetic Analyses ◽  
Chromatid Exchanges ◽  
Deficient Mice ◽  
Insight Into

ABSTRACT The mouse gene Recql is a member of the RecQ subfamily of DEx-H-containing DNA helicases. Five members of this family have been identified in both humans and mice, and mutations in three of these, BLM, WRN, and RECQL4, are associated with human diseases and a cellular phenotype that includes genomic instability. To date, no human disease has been associated with mutations in RECQL and no cellular phenotype has been associated with its deficiency. To gain insight into the physiological function of RECQL, we disrupted Recql in mice. RECQL-deficient mice did not exhibit any apparent phenotypic differences compared to wild-type mice. Cytogenetic analyses of embryonic fibroblasts from the RECQL-deficient mice revealed aneuploidy, spontaneous chromosomal breakage, and frequent translocation events. In addition, the RECQL-deficient cells were hypersensitive to ionizing radiation, exhibited an increased load of DNA damage, and displayed elevated spontaneous sister chromatid exchanges. These results provide evidence that RECQL has a unique cellular role in the DNA repair processes required for genomic integrity. Genetic background, functional redundancy, and perhaps other factors may protect the unstressed mouse from the types of abnormalities that might be expected from the severe chromosomal aberrations detected at the cellular level.

Understanding Control of Exocytotic Secretion in Single Adenohypophysial Cells

Physiology ◽  
1994 ◽  
Vol 9 (5) ◽  
pp. 219-223
Author(s):  
Robert Zorec ◽  
G. Zupančič ◽  
M. Rupnik ◽  
L. Kocmur ◽  
S. Grilc ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Cellular Level ◽  
Membrane Capacitance ◽  
Secretory Cells ◽  
Patch Clamp Technique ◽  
Clamp Technique ◽  
Stimulus Secretion Coupling ◽  
Insight Into

Stimulus-secretion coupling at the cellular level is studied by measuring changes in membrane capacitance in a variety of secretory cells. Attempts to gain new insight into the control of exocytosis in adenohypophysial cells by the patch-clamp technique are briefly outlined.

scholarly journals Single-cell transcriptomics allows novel insights into aging and circadian processes

2020 ◽  
Vol 19 (5-6) ◽  
pp. 343-349
Author(s):  
Sara S Fonseca Costa ◽  
Marc Robinson-Rechavi ◽  
Jürgen A Ripperger
Keyword(s):  
Single Cell ◽  
Single Cells ◽  
Cellular Level ◽  
Biological Processes ◽  
New Methods ◽  
New Findings ◽  
Single Cell Rna Sequencing ◽  
Aging And Circadian Rhythms ◽  
Insight Into ◽  
Different Time Scales

Abstract Aging and circadian rhythms are two biological processes that affect an organism, although at different time scales. Nevertheless, due to the overlap of their actions, it was speculated that both interfere or interact with each other. However, to address this question, a much deeper insight into these processes is necessary, especially at the cellular level. New methods such as single-cell RNA-sequencing (scRNA-Seq) have the potential to close this gap in our knowledge. In this review, we analyze applications of scRNA-Seq from the aging and circadian rhythm fields and highlight new findings emerging from the analysis of single cells, especially in humans or rodents. Furthermore, we judge the potential of scRNA-Seq to identify common traits of both processes. Overall, this method offers several advantages over more traditional methods analyzing gene expression and will become an important tool to unravel the link between these biological processes.

Cardiotonic Steroids: Potential Endogenous Sodium Pump Ligands with Diverse Function11

2002 ◽  
Vol 227 (8) ◽  
pp. 561-569 ◽  
Author(s):  
Renata I. Dmitrieva ◽  
Peter A. Doris
Keyword(s):  
Binding Site ◽  
Intracellular Signaling ◽  
Sodium Pump ◽  
Cellular Level ◽  
Extracellular Potassium ◽  
Sodium Potassium ◽  
A Cell ◽  
Body Fluid Balance ◽  
Sodium And Potassium ◽  
Insight Into

The highly conserved cardiotonic steroid (CS) binding site present on the ubiquitous membrane sodium pump, sodium, potassium-ATPase, appears to have been conserved by no force other than its capacity to bind CS: a family that includes plant-derived cardiac glycosides and putative endogenous vertebrate counterparts. Binding of ligand is inhibited by increased extracellular potassium. This implies functional coordination because inhibition of the sodium pump would be counterproductive when extracellular potassium is elevated. The interesting biology of the CS binding site continues to stimulate investigations into the identity of endogenous ligands, their role as pump regulators at the cellular level, and as mediators of body fluid balance and blood pressure regulation. In addition to inhibition of sodium and potassium transport, there is considerable recent evidence suggesting that the sodium pump may act as a cell signaling receptor activated by CS binding and responding by coordination of intracellular signaling pathways that can be dependent on and also independent of the reduction in transmembrane ion flux resulting directly from pump inhibition. This signaling may influence cell survival, growth, and differentiation. Recent insight into the biology of pump regulation by CS is reviewed.

scholarly journals Detailed Unsteady Simulation of a Counterrotating Aspirated Compressor with a Focus on the Aspiration Slot and Plenum

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Robert D. Knapke ◽  
Mark G. Turner
Keyword(s):  
Mass Flow ◽  
Solid Wall ◽  
Flow Path ◽  
Computational Domain ◽  
Flow Solver ◽  
Wall Boundary Conditions ◽  
Time Histories ◽  
Unsteady Simulation ◽  
Temporal And Spatial ◽  
Insight Into

An unsteady analysis of the MIT counterrotating aspirated compressor (CRAC) has been conducted using the Numeca FINE/Turbo 3D viscous turbulent flow solver with the Nonlinear Harmonic (NLH) method. All three blade rows plus the aspiration slot and plenum were included in the computational domain. Both adiabatic and isothermal solid wall boundary conditions were applied and simulations with and without aspiration were completed. The aspirated isothermal boundary condition solutions provide the most accurate representation of the trends produced by the experiment, particularly at the endwalls. These simulations provide significant insight into the flow physics of the aspiration flow path. Time histories and spanwise distributions of flow properties in the aspiration slot and plenum present a flow field with significant temporal and spatial variations. In addition, the results provide an understanding of the aspiration flow path choking mechanism that was previously not well understood and is consistent with experimental results. The slot and plenum had been designed to aspirate 1% of the flow path mass flow, whereas the experiment and simulations show that it chokes at about 0.5% mass flow.

scholarly journals What are the microscopic events of colloidal membrane fouling?

2019 ◽  
Author(s):  
Matthias Wessling
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Primary Minimum ◽  
Complex Interplay ◽  
Colloidal Fouling ◽  
Basic Understanding ◽  
Temporal And Spatial ◽  
Patchy Colloids ◽  
Discrete Element Methods ◽  
Insight Into

Due to the complex interplay between surface adsorption and hydrodynamic interactions, representative microsocpic mechanisms of colloidal membrane fouling are still not well understood. Numerical simulations overcome experimental limitations such as the temporal and spatial resolution of microscopic events during colloidal membrane fouling: they help to gain deeper insight into fouling processes. This study uses coupled computational fluid dynamics - discrete element methods (CFD-DEM) simulations to examine mechanisms of colloidal fouling in a microfluidic architecture mimicking a porous microfiltration membrane. We pay special attention to how particles can overcome energy barriers leading to adsorption and desorption with each other and with the external and internal membrane surface. Interparticle interaction leads to a transition from the secondary to the primary minimum of the DLVO potential. Adsorbed particles can show re-entrainment or they can glide downstream. Since particles mainly resuspend as clusters, the inner pore geometry significantly affects the fouling behavior. The findings allow a basic understanding of microscopic fouling events during colloidal filtration. The methodology enables future systematic studies on the interplay of hydrodynamic conditions and surface energy contributions represented by potentials for soft and patchy colloids.

Stomatogastric Nervous System

2017 ◽  
Author(s):  
Wolfgang Stein
Keyword(s):  
Nervous System ◽  
Neural Circuit ◽  
Activity Patterns ◽  
Cellular Level ◽  
Target Cells ◽  
Descending Pathways ◽  
Stomatogastric Nervous System ◽  
Motor Circuits ◽  
Insight Into

The crustacean stomatogastric nervous system contains a set of distinct but interacting rhythmic motor circuits that control movements of the foregut. When isolated, these circuits produce activity patterns that are almost perfect replicas of their behavior in vivo. The ease with which distinct circuit neurons are identified, recorded, and manipulated has provided considerable insight into the general principles of how motor circuits operate and are controlled at the cellular level. The small number of relatively large neurons has facilitated several technical advances in neuroscience research and allowed the identification of one of the earliest circuit connectomes. This enabled, for the first time, studies of circuit dynamics using the relationships between all component neurons of a nervous center. A major discovery was that circuits are not dedicated to producing a single neuronal activity pattern, and that the involved neurons are not committed to particular circuits. This flexibility results predominantly from the ability of neuromodulators to change the cellular and synaptic properties of circuit neurons. The relatively unique access to, and detailed documentation of, identified circuit, sensory, and descending pathways has also started new avenues into examining how individual modulatory neurons and transmitters affect their target cells. Groundbreaking experimental and modeling work has further demonstrated that the intrinsic properties of neurons depend on their recent history of activation and that neurons and circuits counterbalance destabilizing influences by compensatory homeostatic regulation of ionic conductances. The stomatogastric microcircuits continue to provide key insight into neural circuit operation in numerically larger and less accessible systems.

X-Ray Diagnostics in the Laser-Initiated Fusion Program

1975 ◽  
Vol 19 ◽  
pp. 533-569
Author(s):  
R. P. Godwin
Keyword(s):  
Energy Transport ◽  
Field Measurements ◽  
Electronic Energy ◽  
Exciting Field ◽  
Temperature Plasma ◽  
X Ray ◽  
X Ray Imaging ◽  
Temporal And Spatial ◽  
Plasma Coupling ◽  
Insight Into

The high-density and high-temperature plasma conditions required for successful laser-initiated fusion make x-ray diagnostics a valuable tool in this exciting field. Measurements of the hard x-ray bremsstrahlung continuum emitted from laser targets provide insight into the complex laser-plasma coupling physics and the subsequent electronic energy transport. X-ray techniques are important in the selection and assay of microballoon targets for current compression experiments. X-ray imaging experiments and diffraction spectroscopy of highly stripped atoms can provide information about the symmetry, density and temperature of laser targets. Extremely high temporal and spatial resolution may be required for definitive diagnostic information on compressed targets. While laser-produced plasmas are interesting as possible intense x-ray sources and as a possible means of achieving x-ray lasing, those topics are outside the scope of this review.

scholarly journals Progress and challenges in using stable isotopes to trace plant carbon and water relations across scales

2012 ◽  
Vol 9 (8) ◽  
pp. 3083-3111 ◽  
Author(s):  
C. Werner ◽  
H. Schnyder ◽  
M. Cuntz ◽  
C. Keitel ◽  
M. J. Zeeman ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Water Relations ◽  
Interdisciplinary Research ◽  
Regional Scale ◽  
Isotope Analysis ◽  
Biogeochemical Processes ◽  
Technological Developments ◽  
Temporal And Spatial ◽  
New Research ◽  
Insight Into

Abstract. Stable isotope analysis is a powerful tool for assessing plant carbon and water relations and their impact on biogeochemical processes at different scales. Our process-based understanding of stable isotope signals, as well as technological developments, has progressed significantly, opening new frontiers in ecological and interdisciplinary research. This has promoted the broad utilisation of carbon, oxygen and hydrogen isotope applications to gain insight into plant carbon and water cycling and their interaction with the atmosphere and pedosphere. Here, we highlight specific areas of recent progress and new research challenges in plant carbon and water relations, using selected examples covering scales from the leaf to the regional scale. Further, we discuss strengths and limitations of recent technological developments and approaches and highlight new opportunities arising from unprecedented temporal and spatial resolution of stable isotope measurements.

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