THE QUANTITATIVE ULTRASTRUCTURE OF THE MERISTEMATIC CELLS OF XANTHIUM STRUMARIUM DURING THE TRANSITION TO FLOWERING

1980 ◽  
Vol 67 (8) ◽  
pp. 1171-1178 ◽  
Author(s):  
A. Havelange
Keyword(s):  
Xanthium Strumarium ◽  
Meristematic Cells ◽  
Quantitative Ultrastructure ◽  
Transition To Flowering

Descriptive and Quantitative Study of Ultrastructural Changes in the Apical Meristem of Mustard in Transition to Flowering

1974 ◽  
Vol 15 (3) ◽  
pp. 633-644
Author(s):  
A. HAVELANGE ◽  
G. BERNIER
Keyword(s):  
Apical Meristem ◽  
Sinapis Alba ◽  
Condensed Chromatin ◽  
Ultrastructural Changes ◽  
Point Counting ◽  
Meristematic Cells ◽  
Long Day ◽  
Genetic Activity ◽  
Loss Of Compactness ◽  
Transition To Flowering

Transition to flowering was induced in the shoot apical meristem of Sinapis alba (mustard), a long-day species, by subjecting vegetative plants to a single 22-h long day. The ultrastructural changes occurring in the meristematic cells during the complete morphogenetic switch were quantitatively investigated using both the planimetric and the point-counting stereological methods. The 2 methods yield very similar results and are thus equally appropriate for the study. The cell, nucleus, and dispersed chromatin sizes are greater in meristems of plants induced to flower (evoked meristems) than in meristems of control vegetative plants. A first size maximum is reached at 26 h after the start of the inductive long day and a second at 54 h. These 2 maxima occur just prior to 2 mitotic waves culminating respectively at 26-30 and 62 h. Neither the condensed chromatin size nor the number of chromocentre profiles per nucleus section change. Consequently the dispersed chromatin: condensed chromatin ratio increases in evoked meristems. This change is discussed in relation to current views on the differential genetic activity of the 2 kinds of chromatin. There is a late but large increase in size of the nucleolus. Dramatic changes in texture are associated with the enlargement of this organelle. These changes are the disappearance of the segregation of fibrillar and granular components and a loss of compactness due to marked vacuolation. All these changes in size and structure are interpreted as indicating a late increase in nucleolar synthesis of ribosomes in the evoked meristems.

The Quantitative Ultrastructure of the Heart Muscle of Japanese Quail by Hypergravitation, Hypodynamy and Combination

1990 ◽  
Vol 48 (3) ◽  
pp. 188-189
Author(s):  
Anton Bózner ◽  
Mikuláš Gažo ◽  
Jozef Dostál
Keyword(s):  
Japanese Quail ◽  
Heart Muscle ◽  
Relative Size ◽  
Combination Group ◽  
Control Group ◽  
Group V ◽  
Group Iii ◽  
Space Flights ◽  
Group I ◽  
Quantitative Ultrastructure

It is anticipated that Japanese quail /Coturnix coturnix japonica/ will provide animal proteins in long term space flights. Consequently this species of birds is of research interest of international space program INTERCOSMOS. In the year 1987 we reported on an experiment /2/ in which the effect of chronic acceleration of 2 G hypergravitation, the hypodynamy and the simultaneous effect of chronic acceleration and the location in the centre of the turntable of the centrifuge on the protein fractions in skeletal muscles was studied. The ultrastructure of the heart muscle was now in this experiments examined as well.Japanese quail cockerels, aged 48 days were exposed to 2 G hypergravitation /group IV/ in a 6,4 m diameter centrifuge, to hypodynamy /group III/ and their combination /group V/, respectively for 6 days / Fig.1/. The hypodynamy in group III was achieved by suspending the birds in jackets without contact the floor. The group II was located in the centre ofthe turntable of the centrifuge. The control group I. was kept under normal conditions. The quantitative ultrastructure of myocard was evaluated by the methods of Weibel/3/ - this enables to determine the number, relative size and volume of mitochondria volume of single mitochondria, defficiency of mitochondrial cristae and volume of myofibrils.

The effect of daylength on the transition to flowering in phytochrome-deficient, late-flowering and double mutants of Arabidopsis thaliana

1995 ◽  
Vol 95 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Maarten Koornneef ◽  
Corrie Hanhart ◽  
Patty van Loenen-Martinet ◽  
Hetty Blankestijn de Vries
Keyword(s):  
Arabidopsis Thaliana ◽  
Late Flowering ◽  
Transition To Flowering

Changes in the polypeptide profiles during photoinduction of Xanthium strumarium

1990 ◽  
Vol 78 (4) ◽  
pp. 519-525 ◽  
Author(s):  
T. Kannangara ◽  
J. P. Durkin ◽  
J. ApSimon ◽  
F. Wightman
Keyword(s):  
Xanthium Strumarium

Histological aspects of the cryopreservation of potato

2008 ◽  
Vol 56 (3) ◽  
pp. 341-348
Author(s):  
P. Pepó ◽  
A. Kovács
Keyword(s):  
Cell Wall ◽  
Low Temperatures ◽  
Cell Walls ◽  
Cellular Level ◽  
Adaptive Mechanism ◽  
Epidermal Layer ◽  
Freezing And Thawing ◽  
Meristematic Cells ◽  
Suitable Solution ◽  
Vacuolated Cells

Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.

scholarly journals Apoptotic Effects of Xanthium strumarium via PI3K/AKT/mTOR Pathway in Hepatocellular Carcinoma

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Juyoung Kim ◽  
Kyung Hee Jung ◽  
Hyung Won Ryu ◽  
Doo-Young Kim ◽  
Sei-Ryang Oh ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Growth ◽  
Caspase 3 ◽  
Mtor Pathway ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Mechanistic Study ◽  
Migration And Invasion ◽  
Xanthium Strumarium ◽  
Apoptotic Effects ◽  
Hcc Cells

Xanthium strumarium (XS) has been traditionally used as a medicinal herb for treating inflammatory diseases, such as appendicitis, chronic bronchitis, rheumatism, and rhinitis. In this study, we yielded ethanol extracts from XS and investigated whether they could inhibit the progression of hepatocellular carcinoma (HCC) and its underlying mechanism. The XS-5 and XS-6 extracts dose-dependently inhibited the growth and proliferation in HCC cell lines. The apoptotic effects of them were observed via increased levels of cleaved caspase-3 and cleaved PARP, as well as elevated numbers of terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling- (TUNEL-) positive apoptotic cells. They also decreased XIAP and Mcl-1 expression via loss of mitochondrial membrane potential. Additionally, they inhibited the invasion and migration of HCC cells. In an ex vivo model, the extracts significantly inhibited tumor cell growth and induced apoptosis by increasing the expression of the cleaved caspase-3. A mechanistic study revealed that they effectively suppressed PI3K/AKT/mTOR signaling pathways in HCC cells. Taken together, our findings demonstrate that they could efficiently not only induce apoptosis but also inhibit cell growth, migration, and invasion of human HCC cells by blocking the PI3K/AKT/mTOR pathway. We suggest XS-5 and XS-6 as novel natural anti-HCC agents.

Influence of cellular metabolites on RNA and protein syntheses by Xanthium nuclei of different developmental phases

1986 ◽  
Vol 64 (12) ◽  
pp. 2922-2927
Author(s):  
A. Jana ◽  
S. P. Sen
Keyword(s):  
Rna Synthesis ◽  
Supernatant Fraction ◽  
Xanthium Strumarium ◽  
Low Molecular Weight ◽  
Transcriptional Level ◽  
Protein Patterns ◽  
Rna Molecules ◽  
Reproductive Tissues ◽  
Developmental Phases ◽  
Vegetative Leaf

Leaf nuclei of vegetative and reproductive plants of Xanthium strumarium L. were incubated with the postribosomal supernatant of either phase and changes at the transcriptional level were studied in homologous and heterologous combinations. In the presence of the supernatant of reproductive plants, RNA synthesis by vegetative nuclei was decreased by 25%. Reproductive nuclei were less active in RNA synthesis. Gel electrophoretic studies revealed four RNA bands in vegetative nuclei incubated with reproductive supernatant, including a fast-moving low molecular weight band that could not be detected when the "vegetative" supernatant was used. The adenine/uracil ratios of the newly synthesized RNA of vegetative nuclei treated with vegetative and reproductive supernatants were 1.46 and 1.54, respectively, compared with 1.15 and 1.04 in the reproductive nuclei. Competitive DNA–RNA hybridization experiments indicated that about 2% of the [3H]RNA synthesized by nuclei of vegetative plants in the presence of the supernatant of reproductive plants could not be beaten out by the RNA of vegetative plants. Small quantitative differences, thus, may be expected in the RNA molecules synthesized by nuclei in the presence of the supernatant fraction of vegetative and reproductive plants. The supernatant fraction of the reproductive tissues decreased the incorporation of [3H]alanine and [3H]leucine in both the buffer-soluble and acid-soluble proteins and the nuclei of vegetative plants were more active in protein synthesis. Protein patterns as studied by acrylamide gel electrophoresis revealed alterations when vegetative leaf nuclei were incubated with the supernatant of reproductive tissues.

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