Changes in cell length and mitotic index in vascular pattern-related pericycle cell types along the apical meristem and elongation zone of the onion root

PROTOPLASMA ◽  
1989 ◽  
Vol 153 (1-2) ◽  
pp. 85-90 ◽  
Author(s):  
P. J. Casero ◽  
C. Garc�a-S�nchez ◽  
P. G. Lloret ◽  
J. Navascu�s
Keyword(s):  
Mitotic Index ◽  
Apical Meristem ◽  
Cell Types ◽  
Cell Length ◽  
Vascular Pattern ◽  
Elongation Zone ◽  
Onion Root ◽  
Pericycle Cell

Growth kinetics in the pericycle cell types along the apical meristem of the onion root

1990 ◽  
Vol 14 ◽  
pp. 101
Author(s):  
P CASERO ◽  
C GARCIASANCHEZ ◽  
P LLORET ◽  
J NAVASCUES
Keyword(s):  
Growth Kinetics ◽  
Apical Meristem ◽  
Cell Types ◽  
Onion Root ◽  
Pericycle Cell

scholarly journals Effects of 5-fluorouracil on the mitotic activity of onion root tips apical meristem

2015 ◽  
Vol 45 (3) ◽  
pp. 225-237
Author(s):  
Waldemar Lechowicz
Keyword(s):  
Cell Division ◽  
Mitotic Activity ◽  
Mitotic Index ◽  
Apical Meristem ◽  
Root Tips ◽  
Onion Root ◽  
Control Value ◽  
Meristematic Cells ◽  
Cytological Changes ◽  
Chromatid Aberrations

The effects of various concentrations of 5-FU on the mitotic activity of onion root tips apical meristem were investigated during 24-hour incubation in 5-FU and postincubation in water. The incubation in 5-FU caused a reversible inhibition of mitotic activity, and waves of the partially synchronised mitoses were observed during the period of postincubation. The most pronounced synchronisation of mitoses was obtained after incubation in 100 mg/l. 5-FU but the mitotic index of the resumed mitotic activity amounted to only one half of the control value. 5-FU was found to cause some cytological changes in meristematic cells such as enlargement of the nucleoli, change in the interphasic nuclei structure, appearance of subchromatid and chromatid aberrations and micronuclei. The effects of 5-FU on nucleic acids and the cell division cycle ace discussed and compared with the effects of 5-FUdR.

Morphological changes and transversal growth kinetics along the apical meristem in the pericycle cell types of the onion adventitious root

PROTOPLASMA ◽  
1991 ◽  
Vol 160 (2-3) ◽  
pp. 108-114 ◽  
Author(s):  
C. Garc�a-S�nchez ◽  
P. J. Casero ◽  
P. G. Lloret ◽  
J. Navascu�s
Keyword(s):  
Growth Kinetics ◽  
Adventitious Root ◽  
Apical Meristem ◽  
Morphological Changes ◽  
Cell Types ◽  
Pericycle Cell

Primary vascular patterns in root meristems of Pontederia cordata and their relevance to studies of root development

1980 ◽  
Vol 58 (12) ◽  
pp. 1351-1369 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Apical Meristem ◽  
Vascular System ◽  
Root Apex ◽  
Root Apical Meristem ◽  
Vascular Pattern ◽  
Quiescent Centre ◽  
Vascular Differentiation ◽  
Pontederia Cordata ◽  
Distribution Of Components ◽  
Root Apices

There are several files of metaxylem cells in root apices of Pontederia cordata L., each considered to consist of a series of prospective vessels with their ends in contact. Two longitudinally adjacent vessels may be in the same file of cells produced by the root apex or in adjacent files. As the root grows, successive prospective vessels are added to the apical ends of most of the files but not all files are continued. Addition of prospective vessels appears to take place within the "quiescent centre" of the root apical meristem. Where files are not continued there is no immediate readjustment of remaining files. The longitudinal and transverse distribution of components of the vascular system (including protophloem and protoxylem) is discussed in relation to the means by which the pattern of development may be controlled. Rates of production of vessels and the final lengths of the vessels are estimated. The observations and deductions are discussed in relation to other studies of root growth, vascular differentiation, and vascular pattern formation and maintenance.

The effect of suberin lamellae on the vitality and symplasmic permeability of the onion root exodermis

1996 ◽  
Vol 74 (8) ◽  
pp. 1220-1226 ◽  
Author(s):  
Carol A. Peterson ◽  
Janet L. Waite
Keyword(s):  
Cell Types ◽  
Ion Transfer ◽  
Onion Root ◽  
Cell Vitality ◽  
Casparian Bands ◽  
Allium Cepa L ◽  
Suberin Lamellae ◽  
Form Part ◽  
Wall Permeability ◽  
Suberin Lamella

The onion exodermis is made up of two cell types, i.e., long and short cells. Both form Casparian bands, but suberin lamella development is absent or delayed in the short cells. Long cells did not accumulate fluorescein, a common test for cell vitality, because of reduced wall permeability due to suberin lamella development. Immature, long cells without lamellae stained in 15 min, whereas mature cells with lamellae required a 3.5- to 4-h treatment before staining was visible. Long exposure to fluorescein was needed to show that mature long cells were alive. Their vitality appeared to decline slowly with age but was not affected by drought stress. Fluorescein staining was apparent in the long cells only after treatment of paradermal sections; when dye was applied only externally to root segments, it did not enter the long cells from the epidermis or from the neighbouring short cells. This result indicates that the long cells were connected symplasmically to the cells of the cortex but were either unconnected, or connected by plasmodesmata of small functional diameter, to the epidermal and short cells. If they were unconnected, they would not form part of the symplasmic path of ion transfer into the root. Keywords: Allium cepa L., drought, exodermis, suberin lamella, vitality.

scholarly journals Are G3 ENETS neuroendocrine neoplasms heterogeneous?

2013 ◽  
Vol 20 (5) ◽  
pp. 649-657 ◽  
Author(s):  
Fritz-Line Vélayoudom-Céphise ◽  
Pierre Duvillard ◽  
Lydia Foucan ◽  
Julien Hadoux ◽  
Cecile N Chougnet ◽  
...  
Keyword(s):  
Mitotic Index ◽  
Somatostatin Receptor ◽  
Neuron Specific Enolase ◽  
Morphological Differentiation ◽  
Large Cell ◽  
Cell Types ◽  
Small Cell ◽  
Neuroendocrine Neoplasms ◽  
Cell Type ◽  
Poorly Differentiated

The new WHO classification of gastroenteropancreatic (GEP) neuroendocrine tumors (NET) implies that G3 neoplasms with mitotic index >20 and/or Ki67 index >20% are neuroendocrine carcinomas (NEC), described as poorly differentiated, small or large cell types, by analogy with lung NEC. To characterize the subgroup of non-small-cell-type GEP and thoracic NET with mitotic index >20 and/or Ki67 >20% according to their pathological features, response to cisplatin and overall survival (OS). We reviewed pathological and clinical presentation of G3 non-small-cell-type NET referred to our institution for 5 years. Data from 166 patients with metastatic thoracic and GEP-NET were collected. Twenty-eight patients (17%) fulfill the inclusion criteria. Tumors were classified as well-differentiated NET (G3-WDNET) in 42.8% of cases and poorly differentiated, large-cell NEC (G3-LCNEC) in 57.2% of cases. Plasma chromogranin A or neuron-specific enolase were elevated in 42 and 25% respectively of G3-WDNET and 31 and 50% of G3-LCNEC. Somatostatin receptor scintigraphy was positive in 88 and 50% of G3-WDNET or G3-LCNEC respectively. Complete or partial response to cisplatin was observed in 31% of cases, all classified as G3-LCNEC. The median OS was 41 months for G3-WDNET but 17 months for G3-LCNEC (P=0.34). Short survival was observed in 25% of G3-WDNET but 62.5% of G3-LCNEC patients (P=0.049). G3 ENETS GEP and thoracic neuroendocrine neoplasms (NEN) could constitute a heterogeneous subgroup of NEN as regards diagnosis, prognosis, and treatment. If confirmed, future classifications may consider splitting them into two groups according to their morphological differentiation.

scholarly journals Classification of 1,198 Cases of Bovine Lymphoma Using the National Cancer Institute Working Formulation for Human Non-Hodgkin's Lymphomas

1992 ◽  
Vol 29 (3) ◽  
pp. 183-195 ◽  
Author(s):  
W. Vernau ◽  
V. E. O. Valli ◽  
T. W. Dukes ◽  
R. M. Jacobs ◽  
M. Shoukri ◽  
...  
Keyword(s):  
Mitotic Index ◽  
National Cancer Institute ◽  
Large Cell ◽  
Cell Types ◽  
High Grade ◽  
Human Beings ◽  
Cell Type ◽  
Follicular Tumors ◽  
Hodgkin's Lymphomas ◽  
Working Formulation

A retrospective histologic study was made of 1,198 cases of bovine lymphoma using the National Cancer Institute Working Formulation for human non-Hodgkin's lymphoma. This classification scheme was found to be readily applicable to bovine lymphoma. Most of the cell types described in the National Cancer Institute Working Formulation occurred in this series of bovine lymphomas, but the distribution of cell types varied markedly compared to that of human beings. Eighty-nine percent (1,067/1,198) of bovine lymphomas were high-grade tumors. The diffuse large cell type and its cleaved variant comprised 65.9% of all bovine lymphomas. Similar to the dog, but in marked contrast to human beings where at least 34% of non-Hodgkin's lymphomas were follicular, follicular tumors were found to be extremely rare in cattle (0.3% or 4/1,198). The prevalence of cell types varied significantly between the enzootic and sporadic lymphomas. The cleaved variant of the diffuse large cell type constituted 38% (406/1,072) of enzootic lymphomas versus 14% (18/126) of sporadic lymphomas. The mitotic index (100 × oil immersion field, 175 μm in diameter) of enzootic lymphomas (3.72 ± 0.06, mean ± standard error) was significantly greater than the mitotic index of sporadic lymphomas (2.82 ± 0.17). We concluded that the cleaved variant of the diffuse large cell type with high mitotic index is characteristic of enzootic lymphoma. This characteristic high-grade cell type may be a consequence of the viral etiology of the enzootic form of bovine lymphoma.

scholarly journals Binding of 1-nitro-9- (3-dimethylaminopropylamino)-acridine to the DNA of the apical meristem cells of adventitious onion (Allium cepa L.) roots

2014 ◽  
Vol 53 (2) ◽  
pp. 217-222
Author(s):  
Danuta Antosiewicz
Keyword(s):  
Allium Cepa ◽  
Apical Meristem ◽  
Root Tips ◽  
Onion Root ◽  
Allium Cepa L ◽  
Covalently Bound

It was established that one half of the ledakrin (I-nitro-9-(3-dimethylaminopropylamino)-acridine) bound to the DNA in the cells of the studied onion root tips (<em>Allium cepa</em> L.), forms labile complexes with it, the remaining half is covalently attached to only one strand of the DNA. One molecule of covalently bound ledakrin falls on average to 10<sup>4</sup>-2X10<sup>4</sup> pairs of bases.

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