A volumetric study of growth and cell division in two types of epithelium,?the longitudinally prismatic epidermal cells of Tradescantia and the radially prismatic epidermal cells of Cucumis

1930 ◽  
Vol 47 (1) ◽  
pp. 59-99 ◽  
Author(s):  
Frederic T. Lewis
Keyword(s):  
Cell Division ◽  
Epidermal Cells ◽  
Volumetric Study

Fine structure of Wolffia arrhiza

1973 ◽  
Vol 51 (9) ◽  
pp. 1619-1622 ◽  
Author(s):  
J. L. Anderson ◽  
W. W. Thomson ◽  
J. A. Swader
Keyword(s):  
Fine Structure ◽  
Cell Division ◽  
Vegetative Reproduction ◽  
Guard Cells ◽  
Epidermal Cells ◽  
Electron Microscopic ◽  
Meristematic Cells ◽  
Wolffia Arrhiza ◽  
Microscopic Studies

Light and electron microscopic studies of Wolffia arrhiza L. frond development during vegetative reproduction showed that the fronds were composed entirely of chlorenchymous cells. Chloroplasts in the epidermal cells other than the guard cells were unique in that they contained no starch. Cell division occurred only at the proximal end of daughter fronds early in their development. Meristematic cells contained chloroplasts with clearly defined grana. Proplastids, commonly observed in meristematic cells of apical regions of other plants, were absent in the cells of these plants.

Divisions cellulaires au niveau de l'épiderme de l'hypocotyle du lin (Linum usitatissimum) cultivé in vitro

1985 ◽  
Vol 63 (10) ◽  
pp. 1691-1695 ◽  
Author(s):  
M. Sqalli ◽  
H. Chlyah
Keyword(s):  
Cell Division ◽  
Culture Cell ◽  
Epidermal Cells ◽  
Isolated Cells ◽  
Initiation And Propagation ◽  
A Cell ◽  
The Mean ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

A study of the initiation and propagation of cell divisions in the epidermis of flax hypocotyl segments cultured in vitro was made using surface observations (light and scanning electron microscopes) as well as transverse and longitudinal sections. Epidermal cells were of two types: long, narrow cells and short, wide cells. The latter, less numerous, rarely participated in cell division. Nuclear activation and the first mitoses appeared very early (after 4–8 h of culture). Cell division began in isolated cells and spread progressively to surrounding cells arranged transversely. At 24 h, approximately 50 cells in division or newly divided were observed on an epidermal strip of 10 × 2 mm composed of about 8000 original cells. At 48 h, about 110 cells had divided forming 22 division centers; 26 prophase, 10 metaphase, and 7 telophase figures were observed. The mean number of original cells which participated in the formation of a cell division center was three at 12 h, five at 72 h, with no increase thereafter. The percentage of cells in mitosis or already divided remained low (1.9%) in relation to the total number of epidermal cells. For 22 division centers, only 7 would participate in vegetative bud formation.

Temporal Pattern of Bristle Development on Drosophila melanogaster Sternites

1982 ◽  
Vol 35 (6) ◽  
pp. 653 ◽  
Author(s):  
JH Claxton
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Division ◽  
Spatial Patterns ◽  
Temporal Pattern ◽  
Epidermal Cells ◽  
X Rays

Bristle development in D. melanogaster can be prevented with X-rays administered prior to the final differentiative divisions of bristle-committed epidermal cells. The epidermal cells are radiationinsensitive if the same dose is given after cell division. By subjecting variously aged early pupae to X-radiation and subsequently scoring bristle numbers in adults, a temporal pattern of radiation insensitivity was established on the abdominal sternites. The pattern is a simple gradient extending anteriorly and medially from the posterior lateral sternite �corners'. The possible significance of this to the origin of bristle spatial patterns is discussed.

Assimilate uptake and the regulation of seed development

1998 ◽  
Vol 8 (3) ◽  
pp. 331-346 ◽  
Author(s):  
Hans Weber ◽  
Ute Heim ◽  
Sabine Golombek ◽  
Ljudmilla Borisjuk ◽  
Ulrich Wobus
Keyword(s):  
Cell Division ◽  
Cell Differentiation ◽  
Seed Development ◽  
Seed Coat ◽  
Storage Proteins ◽  
Active Regions ◽  
Transport Processes ◽  
Epidermal Cells ◽  
Uptake System ◽  
Sucrose Uptake

AbstractSeed development is a series of events involving cell division, followed by cell differentiation and storage activity In legume cotyledons, cell differentiation starts in certain regions and gradually spreads to other parts, thereby building up developmental gradients The entire process appears to be subject to metabolic control The high hexose state of the premature legume embryo as controlled by seed coat-specific invertases favours cell division Differentiation is initiated when hexose decreases and sucrose increases Seed development occurs in a close interaction with seed metabolism and transport processes Movement of photoassimilates from the sieve tubes to the unloading region of the maternal seed tissue is symplasmic and controlled by plasmodesmal passage Sucrose uptake into Vicia faba cotyledons is mediated by a H+-sucrose symporter located in the outer epidermis which generates transfer cells Formation of the sucrose uptake system is induced during the early to mid-cotyledon stage by tissue contact with the maternal seed coat and is controlled by carbohydrate availability In contrast, a hexose transporter gene is also expressed in epidermal cells covering younger, mitotically active regions of the cotyledons The sucrose uptake system apparently generates the high sucrose state immediately preceding the storage phase Sucrose specifically induces storage-associated differentiation processes indicating a specific sucrose-dependent signalling pathway operating in maturing cotyledons Moreover, the mode of sucrose uptake — apoplasmic movement into the epidermal cells with subsequent symplasmic transfer to the storage parenchyma cells — appears to control coordinated cotyledon development Unlike sucrose, amino acid transport into legume cotyledons is passive during early development but at later stages when large amounts of storage proteins are synthesized an additional active uptake system is established to ensure a sufficient supply

The origin and continuous replacement of epidermal cells in the planarian Polycelis tenuis (Iijima)

Development ◽  
1965 ◽  
Vol 13 (1) ◽  
pp. 129-139
Author(s):  
R. J. Skaer
Keyword(s):  
Cell Division ◽  
Early Development ◽  
Epidermal Cells ◽  
Germ Layers ◽  
Motile Cells ◽  
Wide Range ◽  
Migration Of Cells

Raylankester (1873) coined the term ‘Triploblastic’ and supposed that the gut, parenchyma and epidermis of Turbellaria corresponded to the germ layers of contemporary dogma. This idea is still current, though neither the origin, nor the maintenance of the epidermis of planarians has been investigated in detail. Most embryological studies have been restricted to early development, but Bardeen (1902) worked on embryos of a wide range of ages and claimed that their epidermal cells divide amitotically. Both Mattiesen (1904) and Fulińsky (1916), however, denied that cell division occurs there, and since this has been confirmed for the epidermis of the adult (Skaer, 1961), the cells must be recruited from elsewhere. I suggested that the entire epidermis might be continuously renewed by migration of cells from the parenchyma to the periphery. The idea that cells from the parenchyma might enter the epidermis has been put forward several times. Hallez (1887) described motile cells, equivalent to neoblasts, that enter the epidermis throughout development.

scholarly journals Transient Exposure to Ethylene Stimulates Cell Division and Alters the Fate and Polarity of Hypocotyl Epidermal Cells

2004 ◽  
Vol 134 (4) ◽  
pp. 1614-1623 ◽  
Author(s):  
Haruko Kazama ◽  
Haruka Dan ◽  
Hidemasa Imaseki ◽  
Geoffrey O. Wasteneys
Keyword(s):  
Cell Division ◽  
Epidermal Cells

scholarly journals Control of imaginal cell development by the escargot gene of Drosophila

Development ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 105-115 ◽  
Author(s):  
S. Hayashi ◽  
S. Hirose ◽  
T. Metcalfe ◽  
A.D. Shirras
Keyword(s):  
Cell Division ◽  
Zinc Finger ◽  
Imaginal Discs ◽  
Cell Development ◽  
Epidermal Cells ◽  
Normal Functions ◽  
Similar Phenotype ◽  
Snail Gene ◽  
Third Instar Larvae

Mutations in the escargot (esg) locus, which codes for a zinc-finger-containing protein with similarity to the product of the snail gene, cause a variety of defects in adult structures such as loss of abdominal cuticle and malformation of the wings and legs. esg RNA is expressed in wing, haltere, leg and genital imaginal discs and in abdominal histoblast nests in the embryo. Expression in imaginal tissues is also found in third instar larvae. In esg mutant larvae, normally diploid abdominal histoblasts replicate their DNA without cell division and become similar in appearance to the polytene larval epidermal cells. A similar phenotype was also found in imaginal discs of larvae mutant for both esg and the Drosophila raf gene. These results suggest that one of the normal functions of esg may be the maintenance of diploidy in imaginal cells.

Effects of Sub-Lethal High Temperature on An Insect, Rhodnius Prolixus (Stål.)

1968 ◽  
Vol 48 (3) ◽  
pp. 465-473
Author(s):  
A. Y. K. OKASHA
Keyword(s):  
Cell Division ◽  
High Temperature ◽  
Mitotic Activity ◽  
High Temperatures ◽  
Critical Period ◽  
Rhodnius Prolixus ◽  
Epidermal Cells ◽  
Complete Development ◽  
Moulting Hormone ◽  
The Brain

1. In Rhodnius larvae, when moulting is delayed under normal temperature conditions by exposure to high temperature directly after feeding, the brain is needed for a period longer than normal to complete development, i.e. the critical period is postponed. 2. This is associated with a delay in the activation of the thoracic glands and in the mitotic activity in the epidermis. 3. It is suggested that high temperature may act directly on the brain thus inhibiting the secretion of its hormone, although other possibilities are also discussed. 4. The process of wound heating at normal and high temperatures is compared. Injury of the integument results in the ‘activation’ of the epidermal cells and their migration towards the wound. Consequently, a zone of sparse cells is formed which persists at high temperature, since cell division in the epidermis is inhibited. 5. The bearing of the inhibition of cell division on the cessation of moulting at high temperature, even in the presence of the moulting hormone, is discussed.

scholarly journals Single microfilaments mediate the early steps of microtubule bundling during preprophase band formation in onion cotyledon epidermal cells

2016 ◽  
Vol 27 (11) ◽  
pp. 1809-1820 ◽  
Author(s):  
Miyuki Takeuchi ◽  
Ichirou Karahara ◽  
Naoko Kajimura ◽  
Akio Takaoka ◽  
Kazuyoshi Murata ◽  
...  
Keyword(s):  
Cell Division ◽  
Electron Tomography ◽  
Broad Band ◽  
Spatial Relationship ◽  
Preprophase Band ◽  
Epidermal Cells ◽  
Late Prophase ◽  
Band Formation ◽  
Early Stages ◽  
Division Site

The preprophase band (PPB) is a cytokinetic apparatus that determines the site of cell division in plants. It originates as a broad band of microtubules (MTs) in G2 and narrows to demarcate the future division site during late prophase. Studies with fluorescent probes have shown that PPBs contain F-actin during early stages of their development but become actin depleted in late prophase. Although this suggests that actins contribute to the early stages of PPB formation, how actins contribute to PPB-MT organization remains unsolved. To address this question, we used electron tomography to investigate the spatial relationship between microfilaments (MFs) and MTs at different stages of PPB assembly in onion cotyledon epidermal cells. We demonstrate that the PPB actins observed by fluorescence microscopy correspond to short, single MFs. A majority of the MFs are bound to MTs, with a subset forming MT-MF-MT bridging structures. During the later stages of PPB assembly, the MF-mediated links between MTs are displaced by MT-MT linkers as the PPB MT arrays mature into tightly packed MT bundles. On the basis of these observations, we propose that the primary function of actins during PPB formation is to mediate the initial bundling of the PPB MTs.

Separation of wound healing from regeneration in the cockroach leg

Development ◽  
1985 ◽  
Vol 85 (1) ◽  
pp. 177-190
Author(s):  
Paul R. Truby
Keyword(s):  
Wound Healing ◽  
Cell Division ◽  
Critical Point ◽  
Electron Micrographs ◽  
Resting State ◽  
Epidermal Cells ◽  
Moult Cycle ◽  
Scanning Electron Micrographs ◽  
Distal Half ◽  
Scanning Electron

It has been shown that after a critical point in the moult cycle of a cockroach, wound healing can occur but regeneration of pattern does not take place until the following intermoult period. Leg removal after the critical point is used to separate the processes of wound healing and leg regeneration. This permits the study of patterns of cell division resulting from wound healing to be distinguished from those involved in leg regeneration. During wound healing, cell division occurs in the epidermal cells of approximately the distal half of the trochanter. The cells then return to the resting state until after the next ecdysis. Regeneration starts with cell division occurring in the distal half of the trochanter, and then spreading to include cells of the proximal trochanter and distal coxa. This spread and the following patterns of growth and redifferentiation appear to be the same as for regeneration following leg removal prior to the critical point, with the more distal structures completing early stages of regeneration first. Scanning electron micrographs of the cuticle of the trochanter after the ecdysis following leg removal support the evidence from the patterns of cell division in suggesting that the distal half of the trochanter is dedifferentiated during wound healing.

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