Topic
Metaphase
About: Metaphase is a research topic. Over the lifetime, 6925 publications have been published within this topic receiving 291590 citations. The topic is also known as: GO:0007091 & mitotic metaphase/anaphase transition.
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TL;DR: A Brd4-Tat fusion protein that is efficiently taken up by different transformed cells harboring HPV plasmids is developed, suggesting that such peptides may lead to the development of inhibitors of latency for many, if not all, papillomaviruses.
136 citations
TL;DR: It was found that the time required for colchicine to break down metaphase spindles which were organized prior to the commencement of treatment, was directly dependent on the concentration of col chicine used, so the rate of metaphase accumulation over the first hour of treatment cannot be used to determine mitotic rate.
Abstract: 1.
Conditions of culture are described, under which the primary roots of broad bean seedlings show a constant growth rate and Mitotic Index for a limited period of time. It was found that the diurnal fluctuation in root growth and Mitotic Index is eliminated when the plumules of the seedlings are removed.
2.
Experiments with colchicine, acenaphthene.p-diehlorobenzene, α-bromonaphthalene and 8-hydroxyquinoline showed that colchicine was the only spindle inhibitor which caused marked increases in metaphase counts.
3.
Three concentrations of colchicine, 0.1, 0.05 and 0.025%, were found to have similar capacities for metaphase accumulation over treatments of from 1 to 6 hr. duration. With increased durations of treatment, concentration differences were expressed, the weaker concentrations being more efficient than the stronger ones. The depression of the rate of metaphase accumulation which was found in treatments of more than 6 hr. duration is attributed to an inhibitory effect of colchicine which results in slowing the rate of entry of cells into mitosis, i.e. increasing the time spent in interphase.
4.
It was found that the time required for colchicine to break down metaphase spindles which were organized prior to the commencement of treatment, was directly dependent on the concentration of colchicine used. For this reason the rate of metaphase accumulation over the first hour of treatment cannot be used to determine mitotic rate.
5.
The mean number of rnetaphases accumulated in a population of 1000 meristematic cells over a period of from 1 to 6 hr. colchicine treatment, was found to be 30.1 ± 1.3 cells per hour. Allowing for the escape of 2 ± 1 cells per hour from c-metaphase into interphase, the number of cells entering metaphase in 1 hr. was thus determined as being 32.1 ± 1.6.
6.
The rate of entry of cells into metaphase was used to determine the time parameters of the mitotic cycle. The method of calculation and formulae for the kinetics of growth of the cell population are given.
7.
When using the colchicine technique the mean mitotic time and total mitotic cycle time of the meristematic cells was found to be 3.9 ± 0.2 hr. and 24.6 ± 1.5 hr., respectively. It is shown that these values are in close agreement with values determined through the use of other methods.
136 citations
TL;DR: A mathematical model of fission yeast growth and division that encompasses all three crucial checkpoint controls is constructed and is consistent with a broad selection of cell cycle mutants, and the phenotypes of several multiple-mutant strains that have not yet been constructed are predicted.
136 citations
TL;DR: It is shown using in vitro reconstitution assays that PRC1 and kinesin-4, two microtubule-associated proteins required for midzone assembly, can tag microtubULE plus ends, and how biochemically similar microtubules can be differentially marked for selective regulation during the formation of specialized arrays, such as those required for cytokinesis is suggested.
136 citations
TL;DR: Isolated mammalian chromosomes have been quantitatively classified by high resolution flow cytometry and chromosome to chromosome variations in HO and CA3 staining are attributed to variations in chromosomal base composition.
Abstract: Isolated mammalian chromosomes have been quantitatively classified by high resolution flow cytometry. Chinese hamster chromosomes stained with 33258 Hoechst and excited in the UV showed a fluorescence distribution in which the 14 types of Chinese hamster chromosomes were resolved into 16 groups seen as distinct peaks in the distributions. Chinese hamster chromosomes were also stained with both 33258 Hoechst (HO) and chromomycin A3 (CA3); the two dye contents were measured by selective excitation in the UV and at 458 nm in a dual beam flow cytometer. The resulting two parameter distribution (HO versus CA3) showed 10 chromosome groups1. Human strain LLL 761 chromosomes stained with HO and excited in the UV showed a fluorescence distribution in which the 23 types of human chromosomes were resolved into 12 groups. Human chromosomes stained with both HO and CA3 and measured in the dual beam flow cytometer produced two parameter fluorescence distributions which showed 20 groups. The chromosomes associated with each group were determined by quinacrine banding analysis of sorted chromosomes and by DNA cytophotometry of preidentified metaphase chromosomes. The relative HO and CA3 stain content and frequency of occurrence of chromosomes in each group were determined from the fluorescence distributions and compared to the results from DNA cytophotometry. The chromosome to chromosome variations in HO and CA3 staining are attributed to variations in chromosomal base composition.
136 citations