scholarly journals Interplay of cell dynamics and epithelial tension during morphogenesis of the Drosophila pupal wing

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Raphaël Etournay ◽  
Marko Popović ◽  
Matthias Merkel ◽  
Amitabha Nandi ◽  
Corinna Blasse ◽  
...  
Keyword(s):  
Mechanical Model ◽  
Cell Shape ◽  
Shape Change ◽  
Cell Dynamics ◽  
Blade Shape ◽  
Pupal Wing ◽  
The Right ◽  
And Behavior ◽  
The Relationship ◽  
Shape Changes

How tissue shape emerges from the collective mechanical properties and behavior of individual cells is not understood. We combine experiment and theory to study this problem in the developing wing epithelium of Drosophila. At pupal stages, the wing-hinge contraction contributes to anisotropic tissue flows that reshape the wing blade. Here, we quantitatively account for this wing-blade shape change on the basis of cell divisions, cell rearrangements and cell shape changes. We show that cells both generate and respond to epithelial stresses during this process, and that the nature of this interplay specifies the pattern of junctional network remodeling that changes wing shape. We show that patterned constraints exerted on the tissue by the extracellular matrix are key to force the tissue into the right shape. We present a continuum mechanical model that quantitatively describes the relationship between epithelial stresses and cell dynamics, and how their interplay reshapes the wing.

Autonomy and non-autonomy in Drosophila mesoderm determination and morphogenesis

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 853-859 ◽  
Author(s):  
M. Leptin ◽  
S. Roth
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Developmental Program ◽  
Cell Shape Change ◽  
Ventral Furrow ◽  
Large Numbers ◽  
The Individual ◽  
Mutant Cells ◽  
Transplantation Experiments ◽  
Shape Changes

The mesoderm in Drosophila invaginates by a series of characteristic cell shape changes. Mosaics of wild-type cells in an environment of mutant cells incapable of making mesodermal invaginations show that this morphogenetic behaviour does not require interactions between large numbers of cells but that small patches of cells can invaginate independent of their neighbours' behaviour. While the initiation of cell shape change is locally autonomous, the shapes the cells assume are partly determined by the individual cell's environment. Cytoplasmic transplantation experiments show that areas of cells expressing mesodermal genes ectopically at any position in the egg form an invagination. We propose that ventral furrow formation is the consequence of all prospective mesodermal cells independently following their developmental program. Gene expression at the border of the mesoderm is induced by the apposition of mesodermal and non-mesodermal cells.

scholarly journals The Knowledge, Attitude, and Behavior of Hospitalized Patients' Families in the Effort to Prevent COVID-19

2021 ◽  
Author(s):  
Anies Dewi Wirati Indraswari ◽  
Abdul Aziz ◽  
Meircurius Dwi Condro Surboyo
Keyword(s):  
Strong Relationship ◽  
Cross Sectional Study ◽  
Hospitalized Patients ◽  
Chi Square ◽  
Cross Sectional ◽  
Chi Square Test ◽  
Knowledge And Attitude ◽  
The Right ◽  
And Behavior ◽  
The Relationship

Abstract Introduction The coronavirus disease-2019 (COVID-19) pandemic has also hit Indonesia. Until September 2020, cases continued to increase with the highest number in Jakarta. The right behavior needs to be followed to prevent COVID-19; this aspect has a strong relationship with knowledge and attitude. This study aimed to analyze the relationship between the knowledge, attitudes, and behavior of hospitalized patients' families in Fatmawati Hospital, Jakarta, in an effort to prevent COVID-19. Materials and Methods A cross-sectional study was conducted on 300 respondents using a self-administered questionnaire to assess their knowledge, attitude, and behavior about COVID-19. The relationship between knowledge, attitude, and behavior was analyzed using the chi-square test with p < 0.05. Results Most of the participants responded to the questionnaire showing a good knowledge, attitude, and behavior related to the efforts to prevent COVID-19. No relationship was present between knowledge, attitude, and behavior in an effort to prevent COVID-19 (p = 0.414 and p = 0.165). Conclusion The hospitalized patients' families exhibited an adequate level of knowledge, attitude, and preventive behaviors toward COVID-19.

A dominant inhibitory version of the small GTP-binding protein Rac disrupts cytoskeletal structures and inhibits developmental cell shape changes in Drosophila

Development ◽  
1995 ◽  
Vol 121 (3) ◽  
pp. 903-914 ◽  
Author(s):  
N. Harden ◽  
H.Y. Loh ◽  
W. Chia ◽  
L. Lim
Keyword(s):  
Epidermal Cell ◽  
Cell Shape ◽  
Shape Change ◽  
Yeast Cells ◽  
Cell Shape Change ◽  
Gtp Binding ◽  
Wide Range ◽  
Cell Shape Changes ◽  
Germband Retraction ◽  
Shape Changes

The Rho subfamily of Ras-related small GTP-binding proteins is involved in regulation of the cytoskeleton. The cytoskeletal changes induced by two members of this subfamily, Rho and Rac, in response to growth factor stimulation, have dramatic effects on cell morphology. We are interested in using Drosophila as a system for studying how such effects participate in development. We have identified two Drosophila genes, DRacA and DRacB, encoding proteins with homology to mammalian Rac1 and Rac2. We have made transgenic flies bearing dominant inhibitory (N17DRacA), and wild-type versions of the DRacA cDNA under control of an Hsp70 promoter. Expression of the N17DRacA transgene during embryonic development causes a high frequency of defects in dorsal closure which are due to disruption of cell shape changes in the lateral epidermis. Embryonic expression of N17DRacA also affects germband retraction and head involution. The epidermal cell shape defects caused by expression of N17DRacA are accompanied by disruption of a localized accumulation of actin and myosin thought to be driving epidermal cell shape change. Thus the Rho subfamily may be generating localized changes in the cytoskeleton during Drosophila development in a similar fashion to that seen in mammalian and yeast cells. The Rho subfamily is likely to be participating in a wide range of developmental processes in Drosophila through its regulation of the cytoskeleton.

Collagenase secretion accompanying changes in cell shape occurs only in the presence of a biologically active cytokine

1989 ◽  
Vol 92 (3) ◽  
pp. 473-485
Author(s):  
I. Kuter ◽  
B. Johnson-Wint ◽  
N. Beaupre ◽  
J. Gross
Keyword(s):  
Cell Cultures ◽  
Cell Shape ◽  
Cell Function ◽  
Shape Change ◽  
Biologically Active ◽  
Target Cells ◽  
Mixed Cell ◽  
Cell Shape Change ◽  
Cell Shape Changes ◽  
Shape Changes

We have investigated the relationship between collagenase production, cell shape and stimulatory factors in cell culture. In a homogeneous culture of primary rabbit corneal stromal cells, shape change induced by a variety of agents was not effective in stimulating collagenase secretion. Only in the presence of a biologically active cytokine or phorbol myristate acetate was a correlation seen between changes in cell shape (induced by a second agent) and collagenase secretion by these primary cells. Cell shape changes were not, however, necessary for collagenase secretion, since certain concentrations of endotoxin or lactalbumin hydrolysate effected secretion of the enzyme in the absence of morphological changes. With passaged cells or mixed cell cultures, where cell shape change did correlate with collagenase secretion without the addition of an exogenous agent, the production of an effective cytokine (autocrine or paracrine) was demonstrated. Thus cell shape change seems to be neither universally necessary nor sufficient for the stimulation of collagenase secretion. It is proposed that the function of cytokines may be more immediately related to gene expression in this system than is change in the shape of the cell. The hypothesis is presented that cell shape changes may render the target cells receptive to cytokines, perhaps by replacing the need for a natural cytokine cofactor. It is also demonstrated here that the use of passaged cells, mixed cell cultures containing endogenous cytokine-secreting cells or tissue culture additives can profoundly affect the interpretation of the effect of various agents on collagenase secretion, and may lead to observations that are not directly relevant to cell function in vivo.

Platelet Shape Change Evoked by Selective Activation of P2X1 Purinoceptors with α,β-Methylene ATP

2001 ◽  
Vol 85 (02) ◽  
pp. 303-308 ◽  
Author(s):  
Michael Rolf ◽  
Charles Brearley ◽  
Martyn Mahaut-Smith
Keyword(s):  
Inhibitory Action ◽  
Light Transmission ◽  
Shape Change ◽  
Second Messengers ◽  
Receptor Activation ◽  
Selective Activation ◽  
The Relationship ◽  
Shape Changes ◽  
Platelet Shape

SummarySimultaneous measurements of [Ca2+]i and light transmission were used to examine the relationship between P2X1 receptor activation and functional platelet responses. The P2X1 agonist α,β-MeATP evoked a transient [Ca2+]i increase and a reversible decrease in light transmission; both responses required external Ca2+ and the nucleotidase apyrase. The transmission response was due to shape change only, verified by scanning electron microscopy and insensitivity to Reopro, a GPIIbIIIa antagonist. α,β-MeATP stimulated smaller shape changes than ADP, however P2X1 responses had a lifespan of <2 h following resuspension in saline and may be considerably larger in vivo. A peak [Ca2+]i increase of >50 nM was required for detectable shape change. Overlap of concentration-response relationships for α,β-MeATP-evoked [Ca2+]i and shape change suggests that other second messengers are not involved. Therefore, the physiological P2X1 agonist ATP can contribute to platelet activation, in contrast to its previously described inhibitory action at metabotropic platelet purinoceptors.

Study on the Traffic Capacity of Expressway Based on Cellular Automata Model

2014 ◽  
Vol 701-702 ◽  
pp. 172-179
Author(s):  
Xiao Dong Xia ◽  
Lin Ling Xu
Keyword(s):  
Cellular Automata ◽  
Traffic Flow ◽  
Heavy Traffic ◽  
Accident Rate ◽  
Cellular Automata Model ◽  
Traffic Capacity ◽  
Low Load ◽  
The Right ◽  
The Relationship ◽  
Shape Changes

Based on the Nagel-Schrekenberg cellular automaton model of traffic flow, this article analyzed the influence that driving on the right side takes to the traffic flow in the condition of light and heavy traffic. With the combination of fluid dynamics and vehicle dynamics, we established the Cellular Automata model for mixed speed two-lane traffic flow on the rule driving on the right side. Then we used the AHP method to find out the large bus share rate, the number of vehicles changing lanes and the influence law of safety factors on traffic flow. We came to a conclusion that the relationship between traffic flow and load are inverted U shape changes in the low load and high load conditions, the accident rate is the maximum when the V/C (the ratio of traffic flow and the ability of corresponding section) is the minimum; with the increase of V/C, the accident rate decreased gradually.

scholarly journals Desain furnitur hasil kajian seting fisik kelas studio berbasis perilaku mahasiswa milenial

2020 ◽  
Vol 3 (8) ◽  
pp. 285-290
Author(s):  
Dwi Sulistyawati ◽  
Imam Santosa ◽  
Deddy Wahyudi
Keyword(s):  
Information Technology ◽  
Learning Process ◽  
Millennial Generation ◽  
Millennial Students ◽  
Technology Tools ◽  
Starting Point ◽  
The Right ◽  
And Behavior ◽  
The Relationship

Activities and behavior Millennials have special characteristics, as a result of being influenced by information technology tools that bring about changes in various aspects that can have an impact on the problem. The starting point of the problem that must be solved is that the behavior of Millennial students behaves in terms of the learning process in accordance with the applicable curriculum to get the right means of space (physical arrangement) so that it is expected to contribute to the effectiveness in achieving the target of the learning process, which refers to research on activities users, especially the activities of millennial generation lecturers and students in behaving in class. Physical Setings Products that can show the relationship between spatial conditions, needs and behavior of millennial students in class. The results of this study then become the basis for creating a classroom arrangement model that is tailored to the curriculum and characteristics of millennial students. 

Localization of Microfilaments and Microtubules During Functional Shape Changes of Human Platelets (Adhesion, Aggregation, Retraction)

1975 ◽  
Author(s):  
E. Lindner ◽  
M. Inczédy-Marcsek ◽  
R. Dierichs
Keyword(s):  
Cell Shape ◽  
Shape Change ◽  
Blood Clot ◽  
Human Platelets ◽  
Metabolic Inhibitors ◽  
Protoplasmic Streaming ◽  
Electron Microscopic ◽  
Process Formation ◽  
Motile Activity ◽  
Shape Changes

Light and electron microscopic observations on spreading platelets show that microfilaments appear in relation to shape changes. Cell shape and in particular the types of process formation were correlated to the ability of platelets to adhere and aggregate. After activation or inhibition of spreading by Mg+2 and metabolic inhibitors (NaF and Malonic acid) respectively microfilaments and microtubules were localized in agreement with protoplasmic streaming associated with shape change. Contractility of intracellular microfilaments and motile activity of processes is demonstrated in the retracting blood clot. The significance of protoplasmic streaming for platelet function is discussed.

scholarly journals Intercellular signalling, cell fate and cell shape in the Drosophila pupal wing

2017 ◽  
Author(s):  
Aidan Maartens
Keyword(s):  
Cell Fate ◽  
Cell Shape ◽  
Cell Signalling ◽  
Downstream Target ◽  
Dynamic Cell ◽  
Pupal Wing ◽  
Intercellular Signalling ◽  
Cell Shape Changes ◽  
Bmp Signalling ◽  
Shape Changes

The morphogenesis of tissues in animal development is orchestrated by intercellular signalling and executed by cell behaviours such as changes to shape. Understanding the link between signalling and cell shape changes is a key task of developmental biology. This work addresses this problem using the development of the pupal wing of Drosophila melanogaster. The pupal wing is a bilayered epithelium which is patterned into vein and intervein domains, and which secretes the cuticle of the adult wing. I first address the cellular basis of pupal wing development, and show that the process comprises a series of dynamic cell shape changes involving alterations to the apical and basolateral surfaces of the cells. Using temporally controlled mis-expression, I then investigate the role of intercellular signalling in these shape changes, and define the competence of cells in the wing to respond to ectopic signals. The dimensions of signalling in the pupal wing are then investigated, and I show that while BMP ligands can travel between the layers to promote vein development, such signalling is not a prerequisite for cellular differentiation. Within the plane of the epithelium, the BMP ligand Dpp can only induce signalling at a short range, potentially due to the upregulation of receptor levels in receiving cells. Finally, attention is turned to the means by which cell signalling controls cell shape changes, specifically in the crossveins. I identify the RhoGAP Cv-c as a downstream target of BMP signalling which acts to inhibit a novel RhoGTPase function in intervein development. This provides an example of how signalling pathways can enact cell shape changes, via the transcriptional regulation of RhoGAPs.

scholarly journals TissueMiner: A multiscale analysis toolkit to quantify how cellular processes create tissue dynamics

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Raphaël Etournay ◽  
Matthias Merkel ◽  
Marko Popović ◽  
Holger Brandl ◽  
Natalie A Dye ◽  
...  
Keyword(s):  
Multiscale Analysis ◽  
Time Lapse ◽  
Convergent Extension ◽  
Cell Dynamics ◽  
Computational Framework ◽  
Cellular Processes ◽  
Multi Scale ◽  
Pupal Wing ◽  
Shape Changes

Segmentation and tracking of cells in long-term time-lapse experiments has emerged as a powerful method to understand how tissue shape changes emerge from the complex choreography of constituent cells. However, methods to store and interrogate the large datasets produced by these experiments are not widely available. Furthermore, recently developed methods for relating tissue shape changes to cell dynamics have not yet been widely applied by biologists because of their technical complexity. We therefore developed a database format that stores cellular connectivity and geometry information of deforming epithelial tissues, and computational tools to interrogate it and perform multi-scale analysis of morphogenesis. We provide tutorials for this computational framework, called TissueMiner, and demonstrate its capabilities by comparing cell and tissue dynamics in vein and inter-vein subregions of the Drosophila pupal wing. These analyses reveal an unexpected role for convergent extension in shaping wing veins.

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