scholarly journals Distribution of microtubule organizing centers in migrating sheets of endothelial cells.

1981 ◽  
Vol 91 (2) ◽  
pp. 589-594 ◽  
Author(s):  
A I Gotlieb ◽  
L M May ◽  
L Subrahmanyan ◽  
V I Kalnins
Keyword(s):  
Endothelial Cells ◽  
Monolayer Culture ◽  
Cell Movement ◽  
Time Lapse ◽  
Microtubule Organizing Center ◽  
Organizing Center ◽  
Direction Of Movement ◽  
The Relationship ◽  
Wounded Area

This study was designed to investigate the relationship between the position of the microtubule organizing center (MTOC) and the direction of migration of a sheet of endothelial cells (EC). Using immunofluorescence and phase microscopy the MTOC's of migrating EC were visualized as the cells moved into an in vitro experimental wound produced by mechanical denudation of part of a confluent monolayer culture. Although the MTOC's in nonmigrating EC were randomly positioned in relation to the nucleus, in migrating cells the position of the MTOC's changed so that 80% of the cells had the MTOC positioned in front of the nucleus toward the direction of movement of the endothelial sheet. This repositioning of the MTOC occurred within the first 4 h after wounding and was associated with the beginning of migration of EC's into the wounded area as seen by time-lapse cinemicrophotography. These studies focus attention on the MTOC as a cytoskeletal structure that may play a role in determining the direction of cell movement.

scholarly journals Organization of actin cytoskeleton during early endothelial regeneration in vitro

1984 ◽  
Vol 66 (1) ◽  
pp. 39-50
Author(s):  
G. Gabbiani ◽  
F. Gabbiani ◽  
R.L. Heimark ◽  
S.M. Schwartz
Keyword(s):  
Endothelial Cells ◽  
Human Plasma ◽  
Rapid Change ◽  
Cell Movement ◽  
Time Lapse ◽  
Immunofluorescent Staining ◽  
Actin Organization ◽  
Cytoplasmic Actin ◽  
Increased Sensitivity

The pattern of early cell movement after an experimental ‘wound’ and the organization of actin in stationary and moving cultured endothelial cells have been studied by means of: time-lapse photography; indirect immunofluorescence using anti-actin antibodies with and without pretreatment with the actin destabilizing factor present in human plasma; and differential centrifugation and densitometric analysis of stained sodium dodecylsulphate/polyacrylamide gels in order to evaluate the total and relative amounts of G and F-actin. Up to 5 h after a single scratch, movement consists of a coordinate spreading and translocation of a band of about 10 cells from the wound edge. Compared to stationary cells, moving endothelial cells show: no significant changes in the intensity and distribution of immunofluorescent staining with anti-actin antibodies, but an increased sensitivity of cytoplasmic actin, including stress fibres, to the actin-destabilizing factor purified from human plasma; and no significant change in the total amount of actin, but a decreased relative amount of F-actin and a corresponding increased relative amount of G-actin. We conclude that endothelial cell movement in vitro is accompanied by a rapid change in the state of actin organization characterized by an overall decrease in cytoplasmic F-actin.

Conditioning of a culture substratum by the ectodermal layer promotes attachment and oriented locomotion by amphibian gastrula mesodermal cells

1983 ◽  
Vol 59 (1) ◽  
pp. 43-60 ◽  
Author(s):  
N. Nakatsuji ◽  
K.E. Johnson
Keyword(s):  
Cell Migration ◽  
Time Lapse ◽  
Ambystoma Maculatum ◽  
Specific Cell ◽  
Animal Pole ◽  
Micron Diameter ◽  
The Relationship ◽  
Extracellular Fibrils ◽  
Scanning Electron

We have found that ectodermal fragments of Ambystoma maculatum gastrulae deposit immense numbers of 0.1 micron diameter extracellular fibrils on plastic coverslips. When migrating mesodermal cells from A. maculatum gastrulae are seeded on such conditioned plastic substrata, they attach and begin migrating after 15–30 min in vitro. We did a detailed analysis of the relationship between fibril orientation and cell migration using time-lapse cinemicrography, scanning electron microscopy, and a microcomputer with a graphics tablet and morphometric program. We found that cells move in directions closely related to the orientation of fibrils. Usually fibrils are oriented in dense arrays with a predominance of fibrils running parallel to the blastopore-animal pole axis of the explant, and cells move preferentially along lines parallel to the blastopore-animal pole axis. When fibrils are unaligned, cells move at random. We have also shown that cells move with a slightly stronger tendency towards the animal pole direction. These results are discussed concerning the mechanism of specific cell migration during amphibian gastrulation.

scholarly journals An In Vitro Model for Assessing Corneal Keratocyte Spreading and Migration on Aligned Fibrillar Collagen

2018 ◽  
Vol 9 (4) ◽  
pp. 54 ◽  
Author(s):  
Pouriska Kivanany ◽  
Kyle Grose ◽  
Nihan Yonet-Tanyeri ◽  
Sujal Manohar ◽  
Yukta Sunkara ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Cell Movement ◽  
Time Lapse ◽  
Collagen Fibrils ◽  
Fibrillar Collagen ◽  
Freeze Injury

Background: Corneal stromal cells (keratocytes) are responsible for developing and maintaining normal corneal structure and transparency, and for repairing the tissue after injury. Corneal keratocytes reside between highly aligned collagen lamellae in vivo. In addition to growth factors and other soluble biochemical factors, feedback from the extracellular matrix (ECM) itself has been shown to modulate corneal keratocyte behavior. Methods: In this study, we fabricate aligned collagen substrates using a microfluidics approach and assess their impact on corneal keratocyte morphology, cytoskeletal organization, and patterning after stimulation with platelet derived growth factor (PDGF) or transforming growth factor beta 1 (TGFβ). We also use time-lapse imaging to visualize the dynamic interactions between cells and fibrillar collagen during wound repopulation following an in vitro freeze injury. Results: Significant co-alignment between keratocytes and aligned collagen fibrils was detected, and the degree of cell/ECM co-alignment further increased in the presence of PDGF or TGFβ. Freeze injury produced an area of cell death without disrupting the collagen. High magnification, time-lapse differential interference contrast (DIC) imaging allowed cell movement and subcellular interactions with the underlying collagen fibrils to be directly visualized. Conclusions: With continued development, this experimental model could be an important tool for accessing how the integration of multiple biophysical and biochemical signals regulate corneal keratocyte differentiation.

Effect of shear stress upon localization of the Golgi apparatus and microtubule organizing center in isolated cultured endothelial cells

1993 ◽  
Vol 104 (4) ◽  
pp. 1145-1153 ◽  
Author(s):  
D.E. Coan ◽  
A.R. Wechezak ◽  
R.F. Viggers ◽  
L.R. Sauvage
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Cell Migration ◽  
Golgi Apparatus ◽  
Flow Direction ◽  
Microtubule Organizing Center ◽  
Directed Cell Migration ◽  
Time Period ◽  
Significant Difference ◽  
Organizing Center

Despite substantial evidence to suggest that directed cell migration is dependent upon positioning of the Golgi apparatus (GA) and the microtubule organizing center (MTOC), some controversy exists about whether such a relationship is relevant to endothelial cells under flow. The present study was undertaken to provide an indepth investigation of the relationship between shear stress, GA/MTOC localization, cell migration and nuclear position. Bovine carotid endothelial cells were exposed to 22 or 88 dynes/cm2 for 0.5, 2, 8 or 24 h, and localization of their GA/MTOCs was determined relative to the direction of flow. In no-flow control specimens, (0, 0.5, 2, 8 and 24 h) there was no change in the equally distributed GA/MTOCs. In contrast, during the first 8 h at 88 dynes/cm2 and by 2 h at 22 dynes/cm2 there was a significant increase in the number of cells with GA/MTOCs localized upstream to flow direction. The effect was temporary, however, and by 24 h there was no significant difference between the no-flow, 22 and 88 dynes/cm2 specimens. Analysis of GA/MTOC localization with respect to the direction of cell migration determined that 72.5% of no-flow cells possessed GA/MTOCs localized to the sides of nuclei nearest the direction of migration. In contrast, 64% of the specimens shear stressed over the same time period had GA/MTOCs localized to the sides of nuclei opposite the direction of migration. These results suggest that positioning of the GA/MTOC in endothelial cells is not dependent completely upon the direction of migration.(ABSTRACT TRUNCATED AT 250 WORDS)

Imaging of plasmacytoid dendritic cell interactions with T cells

Blood ◽  
2009 ◽  
Vol 113 (1) ◽  
pp. 75-84 ◽  
Author(s):  
María Mittelbrunn ◽  
Gloria Martínez del Hoyo ◽  
María López-Bravo ◽  
Noa B. Martín-Cofreces ◽  
Alix Scholer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Plasmacytoid Dendritic Cell ◽  
Time Lapse ◽  
Cell Interactions ◽  
Type I ◽  
Microtubule Organizing Center ◽  
Immune Synapse ◽  
Organizing Center

Abstract Plasmacytoid dendritic cells (pDCs) efficiently produce type I interferon and participate in adaptive immune responses, although the molecular interactions between pDCs and antigen-specific T cells remain unknown. This study examines immune synapse (IS) formation between murine pDCs and CD4+ T cells. Mature pDCs formed canonical ISs, involving relocation to the contact site of the microtubule-organizing center, F-actin, protein kinase C-θ, and pVav, and activation of early signaling molecules in T cells. However, immature pDCs were less efficient at forming conjugates with T cells and inducing IS formation, microtubule-organizing center translocation, and T-cell signaling and activation. Time-lapse videomicroscopy and 2-photon in vivo imaging of pDC–T-cell interactions revealed that immature pDCs preferentially mediated transient interactions, whereas mature pDCs promoted more stable contacts. Our data indicate that, under steady-state conditions, pDCs preferentially establish transient contacts with naive T cells and show a very modest immunogenic capability, whereas on maturation, pDCs are able to form long-lived contacts with T cells and significantly enhance their capacity to activate these lymphocytes.

In vitro nucleation of microtubules from microtubule-organizing center prepared from cellular slime mold

Cell Motility ◽  
1982 ◽  
Vol 2 (3) ◽  
pp. 257-272 ◽  
Author(s):  
Ryoko Kuriyama ◽  
Chikako Sato ◽  
Yoshio Fukui ◽  
Soryu Nishibayashi
Keyword(s):  
Slime Mold ◽  
Cellular Slime Mold ◽  
Microtubule Organizing Center ◽  
Organizing Center ◽  
Cellular Slime

scholarly journals Virus-Induced Cell Motility

1998 ◽  
Vol 72 (2) ◽  
pp. 1235-1243 ◽  
Author(s):  
Christopher M. Sanderson ◽  
Michael Way ◽  
Geoffrey L. Smith
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Uv Light ◽  
Cell Metabolism ◽  
Cell Movement ◽  
Time Lapse ◽  
Late Gene Expression ◽  
Infected Cells ◽  
And Function

ABSTRACT Many viruses induce profound changes in cell metabolism and function. Here we show that vaccinia virus induces two distinct forms of cell movement. Virus-induced cell migration was demonstrated by an in vitro wound healing assay in which infected cells migrated independently into the wound area while uninfected cells remained relatively static. Time-lapse microscopy showed that the maximal rate of migration occurred between 9 and 12 h postinfection. Virus-induced cell migration was inhibited by preinactivation of viral particles with trioxsalen and UV light or by the addition of cycloheximide but not by addition of cytosine arabinoside or rifampin. The expression of early viral genes is therefore necessary and sufficient to induce cell migration. Following migration, infected cells developed projections up to 160 μm in length which had growth-cone-like structures and were frequently branched. Time-lapse video microscopy showed that these projections were formed by extension and condensation of lamellipodia from the cell body. Formation of extensions was dependent on late gene expression but not the production of intracellular enveloped (IEV) particles. The requirements for virus-induced cell migration and for the formation of extensions therefore differ from each other and are distinct from the polymerization of actin tails on IEV particles. These data show that poxviruses encode genes which control different aspects of cell motility and thus represent a useful model system to study and dissect cell movement.

scholarly journals Radial F-actin Organization During Early Neuronal Development

2018 ◽  
Author(s):  
Durga Praveen Meka ◽  
Robin Scharrenberg ◽  
Bing Zhao ◽  
Theresa König ◽  
Irina Schaefer ◽  
...  
Keyword(s):  
Neuronal Development ◽  
Super Resolution ◽  
Actin Dynamics ◽  
Cell Periphery ◽  
Microtubule Organizing Center ◽  
Actin Organization ◽  
Organizing Center ◽  
Super Resolution Microscopy ◽  
Radial Organization

AbstractThe centrosome is thought to be the major neuronal microtubule-organizing center (MTOC) in early neuronal development, producing microtubules with a radial organization. In addition, albeit in vitro, recent work showed that isolated centrosomes could serve as an actin-organizing center (Farina et al., 2016), raising the possibility that neuronal development may, in addition, require a centrosome-based actin radial organization. Here we report, using super-resolution microscopy and live-cell imaging, F-actin organization around the centrosome with dynamic F-actin aster-like structures with F-actin fibers extending and retracting actively. Photoconversion/photoactivation experiments and molecular manipulations of F-actin stability reveal a robust flux of somatic F-actin towards the cell periphery. Finally, we show that somatic F-actin intermingles with centrosomal PCM-1 satellites. Knockdown of PCM-1 and disruption of centrosomal activity not only affect F-actin dynamics near the centrosome but also in distal growth cones. Collectively the data show a radial F-actin organization during early neuronal development, which might be a cellular mechanism for providing peripheral regions with a fast and continuous source of actin polymers; hence sustaining initial neuronal development.

scholarly journals The role of the ameiotic1 gene in the initiation of meiosis and in subsequent meiotic events in maize.

Genetics ◽  
1993 ◽  
Vol 135 (4) ◽  
pp. 1151-1166 ◽  
Author(s):  
I Golubovskaya ◽  
Z K Grebennikova ◽  
N A Avalkina ◽  
W F Sheridan
Keyword(s):  
Meiotic Division ◽  
Higher Plants ◽  
Gene Interaction ◽  
Microtubule Organizing Center ◽  
Spindle Fiber ◽  
Chromosome Synapsis ◽  
Organizing Center ◽  
Relationship Of ◽  
The Relationship

Abstract Understanding the initiation of meiosis and the relationship of this event with other key cytogenetic processes are major goals in studying the genetic control of meiosis in higher plants. Our genetic and structural analysis of two mutant alleles of the ameiotic1 gene (am1 and am1-praI) suggest that this locus plays an essential role in the initiation of meiosis in maize. The product of the ameiotic1 gene affects an earlier stage in the meiotic sequence than any other known gene in maize and is important for the irreversible commitment of cells to meiosis and for crucial events marking the passage from premeiotic interphase into prophase I including chromosome synapsis. It appears that the period of ameiotic1 gene function in meiosis at a minimum covers the interval from some point during premeiotic interphase until the early zygotene stage of meiosis. To study the interaction of genes in the progression of meiosis, several double meiotic mutants were constructed. In these double mutants (i) the ameiotic1 mutant allele was brought together with the meiotic mutation (afd1) responsible for the fixation of centromeres in meiosis; and with the mutant alleles of the three meiotic genes that control homologous chromosome segregation (dv1, ms43 and ms28), which impair microtubule organizing center organization, the orientation of the spindle fiber apparatus, and the depolymerization of spindle filaments after the first meiotic division, respectively; (ii) the afd1 mutation was combined with two mutations (dsy1 and as1) affecting homologous pairing; (iii) the ms43 mutation was combined with the as1, the ms28 and the dv1 mutations; and (iv) the ms28 mutation was combined with the dv1 mutation and the ms4 (polymitotic1) mutations. An analysis of gene interaction in the double mutants led us to conclude that the ameiotic1 gene is epistatic over the afd1, the dv1, the ms43 and the ms28 genes but the significance of this relationship requires further analysis. The afd gene appears to function from premeiotic interphase throughout the first meiotic division, but it is likely that its function begins after the start of the ameiotic1 gene expression. The afd1 gene is epistatic over the two synaptic mutations dsy1 and as1 and also over the dv1 mutation. The new ameiotic*-485 and leptotene arrest*-487 mutations isolated from an active Robertson's Mutator stocks take part in the control of the initiation of meiosis.

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