scholarly journals A stochastic framework of neurogenesis underlies the assembly of neocortical cytoarchitecture

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Alfredo Llorca ◽  
Gabriele Ciceri ◽  
Robert Beattie ◽  
Fong Kuan Wong ◽  
Giovanni Diana ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Cerebral Cortex ◽  
Progenitor Cells ◽  
Cellular Mechanisms ◽  
Cortical Neurogenesis ◽  
Cell Lineages ◽  
Wide Range ◽  
Stochastic Framework ◽  
Combination Of Methods ◽  
Neuronal Output

The cerebral cortex contains multiple areas with distinctive cytoarchitectonic patterns, but the cellular mechanisms underlying the emergence of this diversity remain unclear. Here, we have investigated the neuronal output of individual progenitor cells in the developing mouse neocortex using a combination of methods that together circumvent the biases and limitations of individual approaches. Our experimental results indicate that progenitor cells generate pyramidal cell lineages with a wide range of sizes and laminar configurations. Mathematical modeling indicates that these outcomes are compatible with a stochastic model of cortical neurogenesis in which progenitor cells undergo a series of probabilistic decisions that lead to the specification of very heterogeneous progenies. Our findings support a mechanism for cortical neurogenesis whose flexibility would make it capable to generate the diverse cytoarchitectures that characterize distinct neocortical areas.

scholarly journals Heterogeneous progenitor cell behaviors underlie the assembly of neocortical cytoarchitecture

2018 ◽  
Author(s):  
Alfredo Llorca ◽  
Gabriele Ciceri ◽  
Robert Beattie ◽  
Fong K. Wong ◽  
Giovanni Diana ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Pyramidal Cell ◽  
Progenitor Cell ◽  
Ventricular Zone ◽  
Pyramidal Cells ◽  
Cellular Mechanisms ◽  
Cell Behaviors ◽  
Cell Lineages ◽  
Wide Range ◽  
Combination Of Methods

SUMMARYThe cerebral cortex contains multiple hierarchically organized areas with distinctive cytoarchitectonical patterns, but the cellular mechanisms underlying the emergence of this diversity remain unclear. Here, we have quantitatively investigated the neuronal output of individual progenitor cells in the ventricular zone of the developing mouse neocortex using a combination of methods that together circumvent the biases and limitations of individual approaches. We found that individual cortical progenitor cells show a high degree of stochasticity and generate pyramidal cell lineages that adopt a wide range of laminar configurations. Mathematical modelling these lineage data suggests that a small number of progenitor cell populations, each generating pyramidal cells following different stochastic developmental programs, suffice to generate the heterogenous complement of pyramidal cell lineages that collectively build the complex cytoarchitecture of the neocortex.

scholarly journals Mechanisms and cell lineages in lymphatic vascular development

Angiogenesis ◽  
2021 ◽  
Author(s):  
Daniyal J. Jafree ◽  
David A. Long ◽  
Peter J. Scambler ◽  
Christiana Ruhrberg
Keyword(s):  
Emerging Technologies ◽  
Vascular Development ◽  
Lymphatic Vessels ◽  
Experimental Techniques ◽  
Knowledge Gaps ◽  
Cellular Mechanisms ◽  
Cell Lineages ◽  
Lymphatic Vasculature ◽  
Lymphatic Development ◽  
Health And Disease

AbstractLymphatic vessels have critical roles in both health and disease and their study is a rapidly evolving area of vascular biology. The consensus on how the first lymphatic vessels arise in the developing embryo has recently shifted. Originally, they were thought to solely derive by sprouting from veins. Since then, several studies have uncovered novel cellular mechanisms and a diversity of contributing cell lineages in the formation of organ lymphatic vasculature. Here, we review the key mechanisms and cell lineages contributing to lymphatic development, discuss the advantages and limitations of experimental techniques used for their study and highlight remaining knowledge gaps that require urgent attention. Emerging technologies should accelerate our understanding of how lymphatic vessels develop normally and how they contribute to disease.

The role of exploratory mechanisms in evolution

1995 ◽  
Vol 349 (1329) ◽  
pp. 297-297
Keyword(s):  
Dynamic Instability ◽  
Specific Mechanism ◽  
Cellular Mechanisms ◽  
Selection Processes ◽  
Wide Range ◽  
Rapid Changes ◽  
Neuronal Processes ◽  
History Of ◽  
Variation And Selection

Many cellular mechanisms use a process of variation and selection to generate specific patterns. Among these, dynamic instability of microtubules has been shown to employ a specific mechanism to intentionally generate variation. In many systems the growth of neurons or neuronal processes is excessive, the final connections being established by stabilization of functional interactions. When changes in neuronal networks take place, such as in metamorphosis, use is made of the plasticity of neuronal connectivity. In the immune system, specific responses are generated by variation and selection. Processes that explore a wide range of conditions and a wide range of structures can be called exploratory processes. These are very robust and capable of responding to damage, variability in the environment and ontogenic changes in the organisms. Such robustness would be useful for adapting to changes that occur during phylogenetic changes as well. Given the extensive history of extinction and radiation in evolution, it may be supposed that these mechanisms have themselves been selected for their capacity to survive rapid changes in the organism and for their ability to generate cellular variation.

Postischemic Revascularization: From Cellular and Molecular Mechanisms to Clinical Applications

2013 ◽  
Vol 93 (4) ◽  
pp. 1743-1802 ◽  
Author(s):  
Jean-Sébastien Silvestre ◽  
David M. Smadja ◽  
Bernard I. Lévy
Keyword(s):  
Progenitor Cells ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Therapeutic Option ◽  
Vascular Wall ◽  
Arterial Disease ◽  
Cellular Mechanisms ◽  
Collateral Growth ◽  
Vessel Growth ◽  
Ischemic Diseases

After the onset of ischemia, cardiac or skeletal muscle undergoes a continuum of molecular, cellular, and extracellular responses that determine the function and the remodeling of the ischemic tissue. Hypoxia-related pathways, immunoinflammatory balance, circulating or local vascular progenitor cells, as well as changes in hemodynamical forces within vascular wall trigger all the processes regulating vascular homeostasis, including vasculogenesis, angiogenesis, arteriogenesis, and collateral growth, which act in concert to establish a functional vascular network in ischemic zones. In patients with ischemic diseases, most of the cellular (mainly those involving bone marrow-derived cells and local stem/progenitor cells) and molecular mechanisms involved in the activation of vessel growth and vascular remodeling are markedly impaired by the deleterious microenvironment characterized by fibrosis, inflammation, hypoperfusion, and inhibition of endogenous angiogenic and regenerative programs. Furthermore, cardiovascular risk factors, including diabetes, hypercholesterolemia, hypertension, diabetes, and aging, constitute a deleterious macroenvironment that participates to the abrogation of postischemic revascularization and tissue regeneration observed in these patient populations. Thus stimulation of vessel growth and/or remodeling has emerged as a new therapeutic option in patients with ischemic diseases. Many strategies of therapeutic revascularization, based on the administration of growth factors or stem/progenitor cells from diverse sources, have been proposed and are currently tested in patients with peripheral arterial disease or cardiac diseases. This review provides an overview from our current knowledge regarding molecular and cellular mechanisms involved in postischemic revascularization, as well as advances in the clinical application of such strategies of therapeutic revascularization.

The timing of cortical neurogenesis is encoded within lineages of individual progenitor cells

2006 ◽  
Vol 9 (6) ◽  
pp. 743-751 ◽  
Author(s):  
Qin Shen ◽  
Yue Wang ◽  
John T Dimos ◽  
Christopher A Fasano ◽  
Timothy N Phoenix ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Cortical Neurogenesis

scholarly journals Estradiol Replacement Alters Expression of Genes Related to Neurotransmission and Immune Surveillance in the Frontal Cortex of Middle-Aged, Ovariectomized Rats

Endocrinology ◽  
2010 ◽  
Vol 151 (8) ◽  
pp. 3847-3862 ◽  
Author(s):  
Miklós Sárvári ◽  
Imre Kalló ◽  
Erik Hrabovszky ◽  
Norbert Solymosi ◽  
Kinga Tóth ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Frontal Cortex ◽  
Expression Profiling ◽  
Hormone Replacement ◽  
Immune Surveillance ◽  
Ovariectomized Rats ◽  
Middle Aged ◽  
Wide Range ◽  
Frontal Cerebral Cortex ◽  
Genomic Effects

Estradiol (E2) modulates a wide range of functions of the frontal cerebral cortex. From the onset of menopause, declining levels of E2 can cause cognitive disturbances and changes in behavior that can be counterbalanced by hormone replacement. To study the effect of E2 replacement on the cortical transcriptome in a rodent model with low serum E2 level, we treated middle-aged, ovariectomized rats with E2 or vehicle using osmotic minipumps for 4 wk. Six animals for each group were selected, and samples of their frontal cortex were subjected to expression profiling using oligonucleotide microarrays. The explored E2-regulated genes were related to neurotransmission (Adora2a, Cartpt, Drd1a, Drd2, Gjb2, Nts, and Tac1), immunity (C3, C4b, Cd74, Fcgr2b, Mpeg1, and RT1-Aw2), signal transduction (Igf2, Igfbp2, Igfbp6, Rgs9, and Sncg), transport (Abca1, Hba-a2, Slc13a3, and Slc22a8), extracellular matrix (Col1a2, Col3a1, Fmod, and Lum), and transcription (Irf7 and Nupr1). Seventy-four percent of the transcriptional changes identified by microarray were confirmed by quantitative real-time PCR. The genes identified by expression profiling indicated that chronic E2 replacement significantly altered the transcriptome of the frontal cortex. The genomic effects of E2 influenced dopaminergic and peptidergic neurotransmission, immune surveillance, adenosine and insulin-like growth factor signaling and transport processes, among other functions. Identification of these novel E2-regulated mechanisms highlights the wide range of genomic responses of the aging female frontal cerebral cortex subjected to hormone replacement. Some of the genomic effects identified in this study may underlie the beneficial effects of E2 on cognition, behavior, and neuroprotection.

Assessment of Certainty of Ventilation Processes Mathematical Modeling

2015 ◽  
Vol 725-726 ◽  
pp. 1255-1260
Author(s):  
Tamara Daciuk ◽  
Vera Ulyasheva
Keyword(s):  
Mathematical Modeling ◽  
Turbulent Flows ◽  
Turbulence Models ◽  
Field Measurements ◽  
Heat Emission ◽  
Emission Sources ◽  
Wide Range ◽  
Calculation Results ◽  
Definition Of ◽  
Semiempirical Models

Numerical experiment has been successfully used during recent 10-15 years to solve a wide range of thermal and hydrogasodynamic tasks. Application of mathematical modeling used to design the ventilation systems for production premises characterized by heat emission may be considered to be an effective method to obtain reasonable solutions. Results of calculation performed with numerical solution of ventilation tasks depend on turbulence model selection. Currently a large number of different turbulence models used to calculate turbulent flows are known. Testing and definition of applicability limits for semiempirical models of turbulence should be considered to be a preliminary stage of calculation. This article presents results of test calculations pertaining to thermal air process modeling in premises characterized by presence of heat emission sources performed with employment of different models of turbulence. Besides, analysis of calculation results and comparison with field measurements data are presented.

scholarly journals Mathematical modeling shows that ball-rolling dung beetles can use dances to avoid competition

2021 ◽  
Author(s):  
Zhanyuan Yin ◽  
Leif Zinn-Brooks
Keyword(s):  
Mathematical Modeling ◽  
Optimal Strategy ◽  
Rolling Direction ◽  
Dung Beetles ◽  
Time Interval ◽  
Angular Deviation ◽  
Ball Rolling ◽  
Wide Range

Abstract Ball-rolling dung beetles shape a portion of dung into a ball and roll it away from the dung pile for later burial and consumption. These beetles perform dances (rotations and pauses) atop their dung balls in order to choose an initial rolling direction and to correct their rolling direction (reorient). Previous mathematical modeling showed that dung beetles can use reorientation to move away from the dung pile more efficiently. In this work, we study if reorientation can help beetles avoid competition (i.e., avoid having their dung balls captured), and if so, under what circumstances? This is investigated by implementing a model with two different type of beetles, a roller with a dung ball and a searcher which seeks to capture that dung ball. We show that reorientation can help rollers avoid searchers in a wide range of conditions, but that there are some circumstances in which rolling without reorienting can be a beetle's optimal strategy. We also show that rollers can minimize the probability that their dung ball is captured without making precise measurements of the time interval between dances or the angular deviation for dances.

scholarly journals Cephalopod Retinal Development Shows Vertebrate-like Mechanisms of Neurogenesis

2021 ◽  
Author(s):  
Francesca Napoli ◽  
Christina M Daly ◽  
Stephanie Neal ◽  
Kyle J McCulloch ◽  
Alexandra Zaloga ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nervous System ◽  
Progenitor Cells ◽  
Cellular Proliferation ◽  
Imaging Techniques ◽  
Nuclear Migration ◽  
Live Imaging ◽  
Cellular Mechanisms ◽  
High Resolution Data ◽  
Interkinetic Nuclear Migration

Neurogenesis, the regulation of cellular proliferation and differentiation in the developing nervous system, is the process that underlies the diversity of size and cell type found in animal nervous systems. Our understanding of how this process has evolved is limited because of the lack of high resolution data and live-imaging methods across species. The retina is a classic model for the study of neurogenesis in vertebrates and live-imaging of the retina has shown that during development, progenitor cells are organized in a pseudostratified neuroepithelium and nuclei migrate in coordination with the cell cycle along the apicobasal axis of the cell, a process called interkinetic nuclear migration. Eventually cells delaminate and differentiate within the boundaries of the epithelium. This process has been considered unique to vertebrates and thought to be important in maintaining organization during the development of a complex nervous system. Coleoid cephalopods, including squid, cuttlefish and octopus, have the largest nervous system of any invertebrate and convergently-evolved camera-type eyes, making them a compelling comparative system to vertebrates. Here we have pioneered live-imaging techniques to show that the squid, Doryteuthis pealeii, displays cellular mechanisms during cephalopod retinal neurogenesis that are hallmarks of vertebrate processes. We find that retinal progenitor cells in the squid undergo interkinetic nuclear migration until they exit the cell cycle, we identify retinal organization corresponding to progenitor, post-mitotic and differentiated cells, and we find that Notch signaling regulates this process. With cephalopods and vertebrates having diverged 550 million years ago, these results suggest that mechanisms thought to be unique to vertebrates may be common to highly proliferative neurogenic primordia contributing to a large nervous system.

Feeding Mathematical Modeling of Superalloy Vacuum-Electromagnetic Casting and its Application

2012 ◽  
Vol 629 ◽  
pp. 171-175
Author(s):  
Wen Zhong Jin ◽  
Su Fang Li ◽  
Wei Zhang
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
New Technology ◽  
Experimental Results ◽  
Electromagnetic Stirring ◽  
Shrinkage Cavity ◽  
Vacuum Casting ◽  
Electromagnetic Casting ◽  
Wide Range

The new technology of superalloy vacuum-electromagnetic casting was developed and the feeding mathematical model melt in vacuum-electromagnetic casting was established. The availability of mathematical model was approved by the experiments of the IN100 superalloy. The experimental results indicate that the feeding capacity of melt in vacuum casting can be greatly increased by imposing the 50Hz, 60A rotating electromagnetic stirring, which can decrease the central shrinkage cavity in superalloy ingots, so the quality of the superalloy ingots can be wide-range improved.

Sign in / Sign up

Export Citation Format

Share Document