Preprophase Microtubule Bands in Some Abnormal Mitotic Cells of Wheat

1969 ◽  
Vol 4 (2) ◽  
pp. 397-420
Author(s):  
J. D. PICKETT-HEAPS
Keyword(s):  
Preprophase Band ◽  
Abnormal Development ◽  
Vascular Bundles ◽  
Root Tips ◽  
Stomatal Complexes ◽  
Abnormal Cells ◽  
A Cell ◽  
Asymmetrical Division ◽  
Wheat Tissues ◽  
Size Of Nuclei

Caffeine treatment of growing wheat tissues was used to form binucleate or polyploid cells; preprophase microtubules in subsequent division cycles in these and some other abnormal cells were then examined. In root tips, binucleate cells or those with greatly enlarged nuclei usually contained one transverse preprophase band of microtubules; sometimes this was slightly asymmetrical or skew, and less commonly two bands were seen. In coleoptile vascular bundles, there were generally two or more bands in the greatly elongated cells, these sometimes appearing in different planes. During formation of the stomatal complexes, preprophase microtubules were almost invariably found where expected, preceding abnormal development both in untreated and also in caffeine-treated material, regardless of the number, disposition or size of nuclei. This occurred even when wall stumps, formed during a previous abortive division, indicated that that previous division was also asymmetrical. It is concluded that the position(s) of preprophase band(s) of microtubules is not particularly influenced by the nucleus or nuclei, being more susceptible to external morphogenetic influences which can persist for some considerable time. Particularly in the case of stomatal complexes, a cell wall seems necessary to seal off or otherwise fulfil the tendency towards asymmetrical division.

Effect of Niacin on Mitochondria of Allium Cepa Root Cells

1967 ◽  
Vol 25 ◽  
pp. 78-79
Author(s):  
M. Arif Hayat
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Hydrogen Transfer ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Root Tips ◽  
Root Cells ◽  
Transfer Processes ◽  
Standard Procedures ◽  
A Cell ◽  
Critical Interest

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.

scholarly journals Analysis of the RNA content of the exosomes derived from blood serum and urine and its potential as biomarkers

2014 ◽  
Vol 369 (1652) ◽  
pp. 20130502 ◽  
Author(s):  
Mu Li ◽  
Emily Zeringer ◽  
Timothy Barta ◽  
Jeoffrey Schageman ◽  
Angie Cheng ◽  
...  
Keyword(s):  
Blood Serum ◽  
Cell Communication ◽  
Cell Culture Model ◽  
Culture Model ◽  
Wide Range ◽  
Abnormal Cells ◽  
A Cell ◽  
Invasive Diagnostics ◽  
Serum And Urine

Exosomes are tiny vesicles (30–150 nm) constantly secreted by all healthy and abnormal cells, and found in abundance in all body fluids. These vesicles, loaded with unique RNA and protein cargo, have a wide range of biological functions, including cell-to-cell communication and signalling. As such, exosomes hold tremendous potential as biomarkers and could lead to the development of minimally invasive diagnostics and next generation therapies within the next few years. Here, we describe the strategies for isolation of exosomes from human blood serum and urine, characterization of their RNA cargo by sequencing, and present the initial data on exosome labelling and uptake tracing in a cell culture model. The value of exosomes for clinical applications is discussed with an emphasis on their potential for diagnosing and treating neurodegenerative diseases and brain cancer.

The preprophase band: possible involvement in the formation of the cell wall

1976 ◽  
Vol 22 (2) ◽  
pp. 403-411 ◽  
Author(s):  
M.J. Packard ◽  
S.M. Stack
Keyword(s):  
Cell Wall ◽  
Allium Cepa ◽  
Cell Walls ◽  
Preprophase Band ◽  
Adjacent Cell ◽  
Root Tips ◽  
Meristematic Cells ◽  
Narrow Region ◽  
The Matrix

Numerous vesicles were observed among the microtubules of the “preprophase” band in prophase cells from root tips of Allium cepa. The content of these vesicles looks similar to the matrix of adjacent cell walls, and these vesicles often appear to be involved in exocytosis. In addition, the cell walls perpendicular to the plane of (beneath) the preprophase band are often differentially thickened compared to the walls lying parallel to the plane of the band. Our interpretation of these observations is that the preprophase band may direct or channel vesicles containing precursors of the cell wall to localized regions of wall synthesis. The incorporation of constituents of the cell wall into a narrow region defined by the position of the preprophase band may be a mechanism that ensures unidirecitonal growth of meristematic cells.

scholarly journals Influence of extract from shoots of Taxus baccata var. elegantissima on ultrastructure and tubulin cytoskeleton of meristematic cells of Allium cepa L. roots

2014 ◽  
Vol 71 (3) ◽  
pp. 211-221 ◽  
Author(s):  
Agnieszka Majewska ◽  
Mirosława Furmanowa ◽  
Kazimierz Głowniak ◽  
Joanna Guzewska ◽  
Alicja Zobel ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Chromatin Condensation ◽  
Preprophase Band ◽  
Taxus Baccata ◽  
Cell Nuclei ◽  
Root Tips ◽  
Meristematic Cells ◽  
Allium Cepa L ◽  
Interphase Cells ◽  
Average Size

We investigated the influence of extract from <em>Taxus baccata</em> var. Elegantissima (TbE) shoots in 1:8 dilution, containing paclitaxel in concentration of 81,6 µg/g fresh mass on ultrastructure and tubulin cytoskeleton of meristematic cells of <em>Allium cepa</em> L. root tips. Incubation time 3, 6, 12 and 24 h was followed with postincubation in water for 12 and 24 h. During shorter incubation (till 12 h) the surface of the cell nuclei decreased and chromatin became condensed (in comparison to control) but after 24 h the average surface increased and chromatin condensation decreased. In the course of incubation the average size of plastids and vacuoles increased. Moreover, after treatment mitochondria and plastids showed degradation of ultrastructure, which was reversed after 12 h of postincubation. Immunocytochemical assays demonstrated that in the course of incubation in the ThE extract, the tubulin cytoskeleton became partially disorganised. In most interphase cells, cortical microtubules (MTs) lost their oval transverse orientation. The preprophase band (PPB) position in the cell was often asymmetrical. The MTs array of the karyokinetic spindle and phragmoplast was also disturbed. These alterations were completely reversed during postincubation.

Hyperplasia: The spread of abnormal cells through a plane lattice

1971 ◽  
Vol 3 (2) ◽  
pp. 210-211 ◽  
Author(s):  
Trevor Williams ◽  
Rolf Bjerknes
Keyword(s):  
Basement Membrane ◽  
Basal Cell ◽  
Basal Layer ◽  
Normal Cells ◽  
Daughter Cells ◽  
Plane Lattice ◽  
Abnormal Cells ◽  
A Cell

When a basal cell divides, both daughter cells remain in the basal layer of the epithelium, with one of the neighbouring cells being pushed out to make room. This fact opens the possibility that a cell with a heritable advantage over the normal cells may gradually produce a clone covering more and more of the basal layer. The advantage in question may consist in a faster rate of division than normal, or a more tenacious hold on the basement membrane; we shall limit consideration to the former situation.

scholarly journals Expression Analysis of PIN Genes in Root Tips and Nodules of Lotus japonicus

2019 ◽  
Vol 20 (2) ◽  
pp. 235 ◽  
Author(s):  
Izabela Sańko-Sawczenko ◽  
Dominika Dmitruk ◽  
Barbara Łotocka ◽  
Elżbieta Różańska ◽  
Weronika Czarnocka
Keyword(s):  
Root Nodule ◽  
Root Nodules ◽  
Quantitative Polymerase Chain Reaction ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Vascular Bundles ◽  
Root Tips ◽  
Gus Reporter ◽  
Gene Assay ◽  
Development And Differentiation

Auxins are postulated to be one of the pivotal factors in nodulation. However, their transporters in Lotus japonicus, the model species for the study of the development of determinate-type root nodules, have been scarcely described so far, and thus their role in nodulation has remained unknown. Our research is the first focusing on polar auxin transporters in L. japonicus. We analyzed and compared expression of PINs in 20 days post rhizobial inoculation (dpi) and 54 dpi root nodules of L. japonicus by real-time quantitative polymerase chain reaction (qPCR) along with the histochemical β-glucuronidase (GUS) reporter gene assay in transgenic hairy roots. The results indicate that LjPINs are essential during root nodule development since they are predominantly expressed in the primordia and young, developing nodules. However, along with differentiation, expression levels of several PINs decreased and occurred particularly in the nodule vascular bundles, especially in connection with the root’s stele. Moreover, our study demonstrated the importance of both polar auxin transport and auxin intracellular homeostasis during L. japonicus root nodule development and differentiation.

scholarly journals Auxin as an inducer of asymmetrical division generating the subsidiary cells in stomatal complexes ofZea mays

2015 ◽  
Vol 10 (3) ◽  
pp. e984531 ◽  
Author(s):  
Pantelis Livanos ◽  
Eleni Giannoutsou ◽  
Panagiotis Apostolakos ◽  
Basil Galatis
Keyword(s):  
Stomatal Complexes ◽  
Asymmetrical Division ◽  
Subsidiary Cells

Hyperplasia: The spread of abnormal cells through a plane lattice

1971 ◽  
Vol 3 (02) ◽  
pp. 210-211 ◽  
Author(s):  
Trevor Williams ◽  
Rolf Bjerknes
Keyword(s):  
Basement Membrane ◽  
Basal Cell ◽  
Basal Layer ◽  
Normal Cells ◽  
Daughter Cells ◽  
Plane Lattice ◽  
Abnormal Cells ◽  
A Cell

When a basal cell divides, both daughter cells remain in the basal layer of the epithelium, with one of the neighbouring cells being pushed out to make room. This fact opens the possibility that a cell with a heritable advantage over the normal cells may gradually produce a clone covering more and more of the basal layer. The advantage in question may consist in a faster rate of division than normal, or a more tenacious hold on the basement membrane; we shall limit consideration to the former situation.

scholarly journals The Alfalfa (Medicago sativa) TDY1 Gene Encodes a Mitogen-Activated Protein Kinase Homolog

1999 ◽  
Vol 12 (10) ◽  
pp. 882-893 ◽  
Author(s):  
Mark A. Schoenbeck ◽  
Deborah A. Samac ◽  
Maria Fedorova ◽  
Robert G. Gregerson ◽  
J. Stephen Gantt ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Medicago Sativa ◽  
Map Kinases ◽  
Root Nodules ◽  
Genomic Clone ◽  
Mitogen Activated Protein Kinase ◽  
Vascular Bundles ◽  
Root Tips ◽  
Pathogen Invasion ◽  
Mitogen Activated Protein

Development of root nodules, specifically induction of cortical cell division for nodule initiation, requires expression of specific genes in the host and microsymbiont. A full-length cDNA clone and the corresponding genomic clone encoding a MAP (mitogen-activated protein) kinase homolog were isolated from alfalfa (Medicago sativa). The genomic clone, TDY1, encodes a 68.9-kDa protein with 47.7% identity to MMK4, a previously characterized MAP kinase homolog from alfalfa. TDY1 is unique among the known plant MAP kinases, primarily due to a 230 amino acid C-terminal domain. The putative activation motif, Thr-Asp-Tyr (TDY), also differs from the previously reported Thr-Glu-Tyr (TEY) motif in plant MAP kinases. TDY1 messages were found predominantly in root nodules, roots, and root tips. Transgenic alfalfa and Medicago truncatula containing a chimeric gene consisting of 1.8 kbp of 5′ flanking sequence of the TDY1 gene fused to the β-glucuronidase (GUS) coding sequence exhibited GUS expression primarily in the nodule parenchyma, meristem, and vascular bundles, root tips, and root vascular bundles. Stem internodes stained intensely in cortical parenchyma, cambial cells, and primary xylem. GUS activity was observed in leaf mesophyll surrounding areas of mechanical wounding and pathogen invasion. The promoter was also active in root tips and apical meristems of transgenic tobacco. Expression patterns suggest a possible role for TDY1 in initiation and development of nodules and roots, and in localized responses to wounding.

Microtubules in plant cell division

1989 ◽  
Vol 47 ◽  
pp. 758-759
Author(s):  
S. M. Wick
Keyword(s):  
Electron Microscopy ◽  
Plant Cell ◽  
Mother Cell ◽  
Immunofluorescence Microscopy ◽  
Plant Cells ◽  
Preprophase Band ◽  
Guard Cells ◽  
Cell Types ◽  
Cell Cortex ◽  
Stomatal Complexes

Immunofluorescence microscopy has proven to be a valuable accompaniment to electron microscopy for study of the cytoskeleton of plant cells. Whereas electron microscopy provides greater resolution and details of the spatial relationships of the cytoskeleton to other cellular components, fluorescence visualization makes it possible to see the three-dimensional organization of cytoskeletal elements without laborious reconstruction of views from serial sections. An area in which immunofluorescence microscopy has been useful is the investigation of how plant cells organize and position the various microtubule arrays that are utilized during mitosis, cytokinesis and cell expansion phases. One of the earliest indications of an impending division in a meristematic plant cell is the formation of a preprophase band of microtubules in the cell cortex, at the site where the new wall will be placed at the subsequent cytokinesis. At its later stages, the band is narrower than when first identifiable. In most cells, preprophase band microtubules have the same general orientation as the preceding interphase microtubules, and so preprophase band formation here could, in theory, be achieved by lateral bundling of microtubules.Cells in which the division site and the preprophase band that marks it are not oriented parallel to interphase microtubules are found in stomatal complexes of grass leaves . Fig. 1 illustrates the arrangement of two such cell types: the guard mother cell, which divides lengthwise to form two guard cells, side-by-side, and the subsidiary mother cell, which undergoes a very asymmetric division to produce one of the pair of lens-shaped subsidiary cells that flank the guard cells. Interphase and preprophase arrangements of microtubules for each cell type are diagrammed in Figs. 2-4. In order to examine how these cell types achieve the reorientation of microtubules that is necessary to progress from interphase to preprophase, sheets of epidermis containing actively dividing stomatal complex cells were examined with immunofluorescence microscopy using antibodies to tubulin. Thin epidermal slices of leaves were fixed and glued down to a slide, whereupon cell walls were enzymatically weakened so that unwanted cell layers could be removed . Because waves of division pass along grass leaves, cells of the same type in a given file tend to be at similar stages, which facilitates deduction of the developmental pattern.

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