Impact d'un traitement par le cycloheximide sur la reprise du cycle et sur les teneurs en protéines du bourgeon cotylédonaire du Pois réactivé par décapitation

1990 ◽  
Vol 68 (2) ◽  
pp. 420-427 ◽  
Author(s):  
Arlette Nougarède ◽  
Pierre Rondet ◽  
Pierre Landré ◽  
Robert Saint-Côme
Keyword(s):  
Protein Content ◽  
Mitotic Activity ◽  
Dna Content ◽  
Nuclear Protein ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
S Phase ◽  
Cytoplasmic Protein ◽  
The Mean ◽  
Low Amplitude

Following ablation of the main stem (decapitation), the mean nuclear protein content of the Pisum cotyledonary bud apical cells increased 35% as early as the 6th hour, just when a massive entry into the S phase was registered, and reached a maximum, with a 157% increase, at the 39th hour, when the mitotic activity was also at its highest. The ratio nuclear protein/nuclear DNA content was then multiplied by 1.8 in comparison with the ratio observed in the G0–1 noncycling nuclei of the inhibited cotyledonary bud. In the bud treated with cycloheximide, the mean nuclear protein content slowly increased following decapitation, but remained greatly inferior to that of the controls. A slight entry into the S phase was noticed at the 24th hour and the mean nuclear protein content, then maximal, increased 32% in comparison with the inhibited buds. In the control buds, the mean protoplasmic proteins content increased 116% at the 39th hour (maximal value), whereas it increased only 25% in the treated buds. Following treatment with cycloheximide, the entry into the S phase was postponed and of low amplitude. However, the recycling nuclei were able to divide. An increase in the mean nuclear and cytoplasmic protein content was a prerequisite if the entry into the S phase of G0–1, nuclei was not to be postponed.

scholarly journals Pattern of DNA increase in macronuclear anlagen of Tetrahymena

1986 ◽  
Vol 83 (1) ◽  
pp. 155-164
Author(s):  
J. Roth ◽  
G. Cleffmann
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
S Phase ◽  
The Mean

By combining cytophotometry with autoradiography, five stages of macronuclear anlagen can be discriminated by their DNA content until the end of the first cell cycle after conjugation in Tetrahymena. DNA increases from 2C to about 32C. Each S-phase is followed by a non-synthetic period. Comparing the mean nuclear DNA content after and before each S-phase revealed that 16C anlagen contain significantly less DNA than twice the amount of 8C anlagen. This is unlike the situation in other S-phases during which the amount of DNA is precisely doubled. In the second cell cycle after conjugation some of the cells increase their macronuclear G2 DNA content beyond the 64C stage, while the majority show a mean G2 content of about 64C.

Changes in chromosome structure, mitotic activity and nuclear DNA content from cells of Allium Test induced by bark water extract of Uncaria tomentosa (Willd.) DC

2006 ◽  
Vol 107 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Mieczysław Kuraś ◽  
Julita Nowakowska ◽  
Elwira Śliwińska ◽  
Radosław Pilarski ◽  
Renata Ilasz ◽  
...  
Keyword(s):  
Mitotic Activity ◽  
Dna Content ◽  
Nuclear Dna ◽  
Chromosome Structure ◽  
Water Extract ◽  
Nuclear Dna Content ◽  
Allium Test ◽  
Uncaria Tomentosa

Nuclear DNA content and minimum generation time in herbaceous plants

1972 ◽  
Vol 181 (1063) ◽  
pp. 109-135 ◽  
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Cycle Time ◽  
Generation Time ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Annual Species ◽  
Cell Cycle Time ◽  
Developmental Processes ◽  
The Mean

Many components of cell and nuclear size and mass are correlated with nuclear DNA content in plants, as also are the durations and rates of such developmental processes as mitosis and meiosis. It is suggested that the multiple effects of the mass of nuclear DNA which affect all cells and apply throughout the life of the plant can together determine the minimum generation time for each species. The durations of mitosis and of meiosis are both positively correlated with nuclear DNA content and, therefore, species with a short minimum generation time might be expected to have a shorter mean cell cycle time and mean meiotic duration, and a lower mean nuclear DNA content, than species with a long mean minimum generation time. In tests of this hypothesis, using data collated from the literature, it is shown that the mean cell cycle time and the mean meiotic duration in annual species is significantly shorter than in perennial species. Furthermore, the mean nuclear DNA content of annual species is significantly lower than for perennial species both in dicotyledons and monocotyledons. Ephemeral species have a significantly lower mean nuclear DNA content than annual species. Among perennial monocotyledons the mean nuclear DNA content of species which can complete a life cycle within one year (facultative perennials) is significantly lower than the mean nuclear DNA content of those which cannot (obligate perennials). However, the mean nuclear DNA content of facultative perennials does not differ significantly from the mean for annual species. It is suggested that the effects of nuclear DNA content on the duration of developmental processes are most obvious during its determinant stages, and that the largest effects of nuclear DNA mass are expressed at times when development is slowest, for instance, during meiosis or at low temperature. It has been suggested that DNA influences development in two ways, directly through its informational content, and indirectly by the physical-mechanical effects of its mass. The term 'nucleotype' is used to describe those conditions of the nucleus which effect the phenotype independently of the informational content of the DNA. It is suggested that cell cycle time, meiotic duration, and minimum generation time are determined by the nucleotype. In addition, it may be that satellite DNA is significant in its nucleotypic effects on developmental processes.

scholarly journals The Complex Cell Cycle of the Dinoflagellate Protoctist Crypthecodinium Cohnii as Studied In Vivo and by Cytofluorimetry

1991 ◽  
Vol 100 (3) ◽  
pp. 675-682 ◽  
Author(s):  
YVONNE BHAUD ◽  
JEAN-MARIE SALMON ◽  
MARIE-ODILE SOYER-GOBILLARD
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
S Phase ◽  
Vegetative Cells ◽  
Crypthecodinium Cohnii ◽  
Daughter Cells ◽  
The Times

The complete cell cycle of the dinoflagellate Crypthecodinium cohnii Biecheler 1938 was observed in vivo in a synchronized heterogeneous population, after DAPI staining of DNA. In a given population, the relative nuclear DNA content in each class of cell was measured using a new numerical image-analysis method that takes into account the total fluorescence intensity (FI), area (A) and shape factor (SF). The visible degree of synchronization of the population was determined from the number of cells with a nuclear content of 1C DNA at ‘synchronization’, time 0. One method of synchronization (method 1), based on the adhesiveness of the cysts, gave no better than 50% synchronization of the population; method 2, based on swimming cells released from cysts cultured on solid medium, gave 73% of cells with the same nuclear DNA content. A scatter plot of data for FI versus A in the first few hours after time 0 showed that the actual degree of synchronization of the population was lower. The length of the C. cohnii cell cycle determined in vivo by light microscopy was 10, 16 or 24 h for vegetative cells giving two, four or eight daughter cells, respectively. Histograms based on the FI measurements showed that in an initially synchronized population observed for 20 h, the times for the first cell cycle were: G1 phase, 6 h; S phase, 1 h 30 min; G2+M, 1h 30 min, with the release of vegetative cells occurring 1 or 2h after the end of cytokinesis. The times for the second cell cycle were G1+S, 3h; G2+M, 2h. FI and A taken together, suggested that the S phase is clearly restricted, as in higher eukaryotes. A and SF, taken together, showed that the large nuclear areas were always in cysts with two or four daughter cells. FI and SF, taken together, showed that the second S phase always occurred after completion of the first nuclear division. Our data concerning the course of the cell cycle in C. cohnii are compared with those from earlier studies, and the control of the number of daughter cells is discussed; this does not depend on the ploidy of the mother cell.

Nuclear DNA content and chromosome numbers throughout the life cycle of the Colonia strain of the myxomycete, Physarum polycephalum

1977 ◽  
Vol 24 (1) ◽  
pp. 95-108
Author(s):  
J. Mohberg
Keyword(s):  
Lactic Acid ◽  
Life Cycle ◽  
Chromosome Number ◽  
Dna Content ◽  
Physarum Polycephalum ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
S Phase ◽  
Dna Analyses

Nuclear DNA content and ploidy have been determined at different stages of the life cycle of the Colonia strain of the myxomycete Physarum polycephalum. Analyses at the plasmodial stage showed that (a) Burton and Fuelgen DNA analyses agreed within 15% with strains which ranged from 0-6 to 3-6 pg of DNA per nucleus; (b) S-phase in Colonia is during the early part of interphase as in the Wisconsin strain; (c) in heterothallic and heterothallic × Colonia crossed strains there are 1-0-1-2 pg of DNA and 70 chromosomes per nucleus and in Colonia 0-6 pg of DNA and 40 chromosomes. Germinating spores of all strains contained one population of cells with about 0-5 pg of DNA and 40 chromosomes and another of larger cells with up to 2-5 pg of DNA and 200 chromosomes. The polyploid nuclei comprised 2–20% of the total in heterothallic strains, 2–65% in heterothallic × Colonia crosses and 25–75% in Colonia. A method was devised for making chromosome spreads of amoebae grown on bacterial lawns. Cells were first exposed to dilute formaldehyde at 26 degrees C for 30 min, then spread on slides with hot lactic acid and strained. Such spreads of CLd (Colonia) and RSD4 (heterothallic) amoebae both contained about 40 chromosomes. The data are consistent with the view that Colonia is haploid throughout its life cycle and that chromosome number is neither halved during sporulation nor doubled during plasmoidal formation. However, the possibility exists that an alternance of ploidy occurs by way of the few diploid nuclei present in the plasmodium.

scholarly journals Mitotic activity and changes in DNA content during Zea mays L. endosperm development

2014 ◽  
Vol 71 (3) ◽  
pp. 195-200
Author(s):  
Hanna Kuran ◽  
Kazimierz Marciniak
Keyword(s):  
Zea Mays ◽  
Mitotic Activity ◽  
Dna Content ◽  
Nuclear Dna ◽  
Zea Mays L ◽  
Nuclear Dna Content ◽  
Staining Intensity ◽  
Endosperm Development ◽  
Dna Contents ◽  
Mitotic Figures

Mitotic activity and nuclear DNA content in endosperm of <em>Zea mays</em> cv. Złota Karłowa were examined. DNA content was cytophotometrically measured on squashed preparations after Feulgen procedure. Mitotic activity in endosperm was determined till the stage when embryo sack reached 4.5 mm in length. Some of mitotic figures show multiplied DNA content. Endosperm nuclei have various DNA contents which increase throughout endosperm development. DNA content enhancement indicates endoreduplication in progress. Some nuclei with high DNA content display changes in chromatin structure, which are expressed by the presence of strands and aggregates of chromatin characterised by high staining intensity. A conclusion has been drawn that mitotic divisions and the endoreduplication phase of nuclear DNA may occur simultaneously and dominate one over another at different phases of endosperm development.

Effects of Spent Pot Liner on mitotic activity and nuclear DNA content in meristematic cells of Allium cepa

2012 ◽  
Vol 107 ◽  
pp. 140-146 ◽  
Author(s):  
Larissa Fonseca Andrade-Vieira ◽  
José Marcello Salabert de Campos ◽  
Lisete Chamma Davide
Keyword(s):  
Mitotic Activity ◽  
Allium Cepa ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Meristematic Cells

Genome size variation in Corchorus olitorius (Malvaceae s.l.) and its correlation with elevation and phenotypic traits

Genome ◽  
2011 ◽  
Vol 54 (7) ◽  
pp. 575-585 ◽  
Author(s):  
Solomon Benor ◽  
Jörg Fuchs ◽  
Frank R. Blattner
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Phenotypic Traits ◽  
Corchorus Olitorius ◽  
Genome Size Variation ◽  
Crop Species ◽  
Plant Materials ◽  
The Mean

In this study, we report genome size variations in Corchorus olitorius L. (Malvaceae s.l.), a crop species known for its morphological plasticity and broad geographical distribution, and Corchorus capsularis L., the second widely cultivated species in the genus. Flow cytometric analyses were conducted with several tissues and nuclei isolation buffers using 69 accessions of C. olitorius and 4 accessions of C. capsularis, representing different habitats and geographical origins. The mean 2C nuclear DNA content (± SD) of C. olitorius was estimated to be 0.918 ± 0.011 pg, with a minimum of 0.882 ± 0.004 pg, and a maximum of 0.942 ± 0.004 pg. All studied plant materials were found to be diploid with 2n = 14. The genome size is negatively correlated with days to flowering (r = –0.29, p < 0.05) and positively with seed surface area (r = 0.38, p < 0.05). Moreover, a statistically significant positive correlation was detected between genome size and growing elevation (r = 0.59, p < 0.001) in wild populations. The mean 2C nuclear DNA content of C. capsularis was estimated to be 0.802 ± 0.008 pg. In comparison to other economically important crop species, the genome sizes of C. olitorius and C. capsularis are much smaller, and therewith closer to that of rice. The relatively small genome sizes will be of general advantage for any efforts into genomics or sequencing approaches of these species.

scholarly journals IMAGE ANALYSIS OF CHROMATIN IN CELLS OF PREIMPLANTATION MOUSE EMBRYOS

1974 ◽  
Vol 63 (1) ◽  
pp. 227-233 ◽  
Author(s):  
Wojciech Sawicki ◽  
Jan Rowínski ◽  
Jan Abramczuk
Keyword(s):  
Cell Cycle ◽  
Image Analysis ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Mouse Embryos ◽  
Stage Of Development ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
The Mean

Mouse two-celled embryos and blastulae were Feulgen stained and the DNA content of their nuclei was measured with an integrating microdensitometer. The cells considered on the basis of their nuclear DNA content to be in G1, S, and G2 phases of the cell cycle were selected and their total chromatin area and chromatin areas at different gray levels were measured by the image analyzing computer, Quantimet. The measurements were aimed at quantitation of several features of the chromatin morphology of cells in different functional states. The total area of chromatin was found to increase, and the mean density of chromatin to decrease, from the G1 to the G2 phase of the cell cycle in both two-celled embryos and blastulae. The area of chromatin decreased, and the mean density of chromatin increased, as embryos developed from two-celled to blastula stage. It was concluded that nuclear morphology in preimplantation mouse embryos depends on both the phase of the cell cycle and the stage of development. The method of image analysis described was found to be useful for quantitation of changes in chromatin morphology.

Sign in / Sign up

Export Citation Format

Share Document