Induction, polarity and spatial control of cytokinesis in some abnormal subsidiary cell mother cells ofZea mays

PROTOPLASMA ◽  
1987 ◽  
Vol 140 (1) ◽  
pp. 26-42 ◽  
Author(s):  
P. Apostolakos ◽  
B. Galatis
Keyword(s):  
Subsidiary Cell ◽  
Spatial Control ◽  
Mother Cells

The involvement of phospholipases C and D in the asymmetric division of subsidiary cell mother cells ofZea mays

2008 ◽  
Vol 65 (11) ◽  
pp. 863-875 ◽  
Author(s):  
Panagiotis Apostolakos ◽  
Emmanuel Panteris ◽  
Basil Galatis
Keyword(s):  
Asymmetric Division ◽  
Subsidiary Cell ◽  
Mother Cells

Synchronous organization of two preprophase microtubule bands and final cell plate arrangement in subsidiary cell mother cells of someTriticum species

PROTOPLASMA ◽  
1983 ◽  
Vol 117 (1) ◽  
pp. 24-39 ◽  
Author(s):  
B. Galatis ◽  
P. Apostolakos ◽  
C. Katsaros
Keyword(s):  
Cell Plate ◽  
Subsidiary Cell ◽  
Cell Plate Arrangement ◽  
Mother Cells

Positional inconsistency between preprophase microtubule band and final cell plate arrangement during triangular subsidiary cell and atypical hair cell formation in two Triticum species

1984 ◽  
Vol 62 (2) ◽  
pp. 343-359 ◽  
Author(s):  
B. Galatis ◽  
P. Apostolakos ◽  
C. Katsaros
Keyword(s):  
Hair Cell ◽  
Mitotic Spindle ◽  
Cell Plate ◽  
Subsidiary Cell ◽  
Transverse Wall ◽  
Cortical Zone ◽  
Preprophase Microtubule Band ◽  
Mutual Disposition ◽  
Cell Plate Arrangement ◽  
Mother Cells

On the leaf epidermis of two Triticum species examined, an intervening cell of a stomatal or a hair row often flanks on one side two guard cell mother cells (GMC's) and usually functions twice as a subsidiary cell mother cell (SMC). In many of these cells and rarely in SMC's corresponding to one GMC, a triangular subsidiary cell (SC) instead of a lens-shaped one is formed. Some of these SC's in median paradermal sections appear triangular in form, while in internal and (or) external ones they exhibit a lenslike shape. In all SMC's investigated in which a triangular SC was expected to be formed, the preprophase microtubule band (PMB) occupied the usual position adjacent to the inducing GMC, except for instances in which the transverse wall of the SMC intersected the lateral wall of the GMC or was opposite its transverse wall. Therefore, during triangular SC formation a limited portion of the junction region of the cell plate with the parent walls is predicted by the PMB. In such cases the premitotic polarizing process in the SMC's and consequently the mutual disposition between the PMB and the mitotic spindle is disturbed. The PMB's of the hair cell mother cells (HMC's) are not so densely grouped as those of the SMC's, sometimes occupying an extensive portion along the walls. They were localized at the expected positions at the polar end of the cells. Only in few instances were atypical PMB's organized. However, the cell plate separating the hair cells (HC's) sometimes diverges and fuses with the parent walls at unpredictable positions far from the PMB cortical zone, except for a small part of it adjacent to one longitudinal anticlinal wall of the HMC. In addition, the preprophase–prophase nucleus often occupied an eccentric position in relation to the PMB or more rarely was situated outside it. Sometimes it exhibited a particular orientation. Moreover, mitotic spindles inclined in relation to the PMB plane were frequently observed. The above phenomena seem to be the result of the interference of a transverse polarizing stimulus with an axial one or of the establishment of an aberrant polarity in the HMC's for unknown reasons. The observations suggest that the spatial inconsistency between PMB and final cell plate arrangement in the cells investigated is an exception to the rule, caused by the disturbance of the mutual disposition and orientation between PMB cortical zone and mitotic spindle; these phenomena follow the disorder of the polarizing process of the cells. The PMB cortical zone seems to be effective only when the cell plate edges reach a critical distance from it.

Microtubule Orientation During Stomatal Differentiation in Grasses

1989 ◽  
Vol 92 (4) ◽  
pp. 581-594
Author(s):  
SOON-OK CHO ◽  
SUSAN M. WICK
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Guard Cell ◽  
Mother Cell ◽  
Early Stage ◽  
Preprophase Band ◽  
Subsidiary Cell ◽  
Stomatal Complex ◽  
Face View ◽  
Mother Cells

The changing orientation of microtubules (MTs) during formation of the stomatal complex in grasses was observed by immunofluorescence microscopy, beginning with the asymmetrical division of the cell that gives rise to the guard cell mother cell, i.e. the guard cell grandmother cell. The asymmetrically placed preprophase band (PPB) of guard cell grandmother cells and hair cell mother cells is always laid down parallel to the distal end wall even when this wall is oblique to the long axis of the cell. The first step in formation of the PPB of a subsidiary cell mother cell appears to be establishment of an incomplete band of MTs. Whereas the mature PPB forms a curved line in a face view of a subsidiary cell mother cell, in this early stage MTs form fan-shaped arrays that focus on two points along the edge of the subsidiary cell mother cell. Replacement of the transversely oriented interphase microtubule band of the guard cell mother cell with the longitudinally oriented PPB involves several distinctive stages: (1) appearance of MTs directed toward the centre of the periclinal surface along the entire length of the lateral walls. (2) Appearance of another set of MTs along the entire width of both end walls, likewise focused toward the centre of the periclinal surface. Together these two groups of MTs form a cross with broadened tips in face view of the leaf. (3) Disappearance of the first set of MTs, and formation of an increasingly narrow band from the latter at the site of future cytokinesis. Although the anaphase spindles of guard cell grandmother cells, hair cell mother cells and guard cell mother cells are usually diagonally oriented relative to the site occupied previously by the PPB, the line connecting the centres of the spindle poles that are established at prophase is perpendicular to the persisting PPBs. Unlike the situation in certain other hair cells, MTs in leaf hair cells are transversely oriented even when the cells are highly elongated.

The role of landmark-goal distance on spatial control and integration in pigeons

2010 ◽  
Author(s):  
Cynthia Fast ◽  
Dennis Garlick ◽  
Aaron P. Blaisdell
Keyword(s):  
Spatial Control ◽  
Goal Distance

Book reviews

2017 ◽  
Vol 5 (2) ◽  
pp. 215-226
Author(s):  
Kurdish Studies
Keyword(s):  
19Th Century ◽  
Spatial Control ◽  
Cornell University ◽  
South Eastern ◽  
Turkish State ◽  
The 19Th Century

Andrea Fischer-Tahir and Sophie Wagenhofer (edsF), Disciplinary Spaces: Spatial Control, Forced Assimilation and Narratives of Progress since the 19th Century, Bielefeld: Transcript Verlag, 2017, 300 pp., (ISBN: 978-3-8376-3487-7).Ayşegül Aydın and Cem Emrence, Zones of Rebellion: Kurdish Insurgents and the Turkish State, Ithaca and London: Cornell University Press, 2015, 192 pp., (ISBN: 978-0-801-45354-0).Evgenia I. Vasil’eva, Yugo-Vostochniy Kurdistan v XVI-XIX vv. Istochnik po Istorii Kurdskikh Emiratov Ardelan i Baban. [South-Eastern Kurdistan in the XVI-XIXth cc. A Source for the Study of Kurdish Emirates of Ardalān and Bābān], St Petersburg: Nestor-Istoria, 2016. 176 pp., (ISBN 978-5-4469-0775-5).Karin Mlodoch, The Limits of Trauma Discourse: Women Anfal Survivors in Kurdistan-Iraq, Berlin: Klaus Schwarz Verlag, 2014, 541 pp., (ISBN: 978-3-87997-719-2). 

SPECTRALLY VARIABLE SOURCE BASED ON SPATIAL CONTROL OF WHITE-LIGHT BEAM

2018 ◽  
Author(s):  
Dong-Hoon Lee ◽  
Seongchong Park ◽  
Jae-Keun Yoo ◽  
Jisoo Hwang
Keyword(s):  
Light Beam ◽  
White Light ◽  
Spatial Control ◽  
Variable Source

Magnetic Fields Enable Precise Spatial Control of Electrospun Fiber Alignment for Fabricating Complex Gradient Materials

2020 ◽  
Author(s):  
R. Kevin Tindell ◽  
Lincoln Busselle ◽  
Julianne Holloway
Keyword(s):  
Magnetic Field ◽  
Electrospun Fiber ◽  
Cell Phenotype ◽  
Fibrous Materials ◽  
Fibrous Scaffold ◽  
Spatial Control ◽  
Fiber Alignment ◽  
Aligned Fibers ◽  
The Magnetic Field ◽  
Magnetically Assisted

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>

Magnetic Fields Enable Precise Spatial Control of Electrospun Fiber Alignment for Fabricating Complex Gradient Materials

2020 ◽  
Author(s):  
R. Kevin Tindell ◽  
Lincoln Busselle ◽  
Julianne Holloway
Keyword(s):  
Magnetic Field ◽  
Electrospun Fiber ◽  
Cell Phenotype ◽  
Fibrous Materials ◽  
Fibrous Scaffold ◽  
Spatial Control ◽  
Fiber Alignment ◽  
Aligned Fibers ◽  
The Magnetic Field ◽  
Magnetically Assisted

<div>Musculoskeletal interfacial tissues consist of complex gradients in structure, cell phenotype, and biochemical signaling that are important for function. Designing tissue engineering strategies to mimic these types of gradients is an ongoing challenge. In particular, new fabrication techniques that enable precise spatial control over fiber alignment are needed to better mimic the structural gradients present in interfacial tissues, such as the tendon-bone interface. Here, we report a modular approach to spatially controlling fiber alignment using magnetically-assisted electrospinning. Electrospun fibers were highly aligned in the presence of a magnetic field and smoothly transitioned to randomly aligned fibers away from the magnetic field. Importantly, magnetically-assisted electrospinning allows for spatial control over fiber alignment at sub-millimeter resolution along the length of the fibrous scaffold similar to the native structural gradient present in many interfacial tissues. The versatility of this approach was further demonstrated using multiple electrospinning polymers and different magnet configurations to fabricate complex fiber alignment gradients. As expected, cells seeded onto gradient fibrous scaffolds were elongated and aligned on the aligned fibers and did not show a preferential alignment on the randomly aligned fibers. Overall, this fabrication approach represents an important step forward in creating gradient fibrous materials and are promising as tissue-engineered scaffolds for regenerating functional musculoskeletal interfacial tissues. <br></div>

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