scholarly journals Isolated metaphase chromosomes. II. Proteins of Chinese hamster chromosomes.

1979 ◽  
Vol 27 (1) ◽  
pp. 454-457 ◽  
Author(s):  
W Wray ◽  
V P Wray
Keyword(s):  
Flow Cytometric Analysis ◽  
Chinese Hamster ◽  
High Capacity ◽  
Microscopic Analysis ◽  
Metaphase Chromosomes ◽  
Chromosomal Proteins ◽  
Quantitative Evidence ◽  
Flow Cytometric ◽  
Velocity Gradients

The proteins on metaphase chromosomes theoretically may be distributed ubiquitously throughout the karyotype, may be present uniquely on individual chromosomes or classes of chromosomes, or may exist in any combination of the above. Separation of chromosomes according to size using sucrose velocity gradients in high capacity zonal centrifuge rotors allows sufficient fractionation of the genome to indicate the distribution of proteins within the karyotype. Flow cytometric analysis and direct microscopic analysis were used to evaluate qualitatively the types of chromosomes present in the fractions obtained. This report is the first quantitative evidence that some of the chromosomal proteins are not distributed ubiquitously on all of the chromosomes of the karyotype.

Cell synchronization and isolation of metaphase chromosomes from maize (Zea mays L.) root tips for flow cytometric analysis and sorting

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Jai-Heon Lee ◽  
K. Arumuganathan ◽  
S. M. Kaeppler ◽  
C. M. Papa ◽  
H. F. Kaeppler
Keyword(s):  
Cell Cycle ◽  
Flow Cytometric Analysis ◽  
Maize Root ◽  
Root Tip ◽  
Root Tips ◽  
Chromosome Sorting ◽  
Synthesis Inhibitor ◽  
Metaphase Chromosomes ◽  
Flow Karyotype ◽  
Flow Cytometric

Accumulation of cells containing metaphase chromosomes is an important step in cytological analyses and chromosome sorting procedures. The goal of this research was to optimize treatment parameters to synchronize the cell cycle of maize root tip meristem cells. Levels of hydroxyurea, a DNA synthesis inhibitor, were assessed for their utility in accumulating cells at the G1 phase of the cell cycle. Trifluralin, amiprophos-methyl, and colchicine were used to accumulate cells containing metaphase chromosomes upon release from hydroxyurea inhibition. Optimal mitotic indices were achieved by treating seedlings with 5 mM hydroxyurea for 18 h, incubating for 1 h without chemical treatment to release the hydroxyurea block, and then treating emerging roots with 1 μM trifluralin for 4 h. The mitotic index of synchronized maize root tips was over 70%. Uniformity of synchronization depended upon selection of seeds with emerging radicles that were similar in length at the time of treatment. Suspensions of intact chromosomes were prepared by a simple slicing procedure. The chromosome preparations were found to be suitable for flow cytometric characterization and sorting. Chromosome peaks of the observed flow karyotype resembled the predicted flow karyotype calculated on the basis of maize chromosome size. Key words : flow karyotype, hydroxyurea, plant chromosome sorting, trifluralin.

scholarly journals Flow cytometric analysis of bromodeoxyuridine-substituted cells stained with 33258 Hoechst.

1977 ◽  
Vol 25 (7) ◽  
pp. 927-934 ◽  
Author(s):  
S A Latt ◽  
Y S George ◽  
J W Gray
Keyword(s):  
Flow Cytometry ◽  
Cell Growth ◽  
Deoxyribonucleic Acid ◽  
Flow Cytometric Analysis ◽  
Chinese Hamster ◽  
Acid Synthesis ◽  
Whole Cells ◽  
Flow Cytometric ◽  
Deoxyribonucleic Acid Synthesis ◽  
Average Fluorescence

This paper describes a flow-cytometric application of the quenching of fluorescence from 33258 Hoechst stained Chinese hamster ovary-line cells due to the incorporation of 5-bromo-deoxyuridine (BrdU) into the cellular deoxyribonucleic acid. Cells were grown for 24 hr in medium containing BrdU in concentrations ranging from 1 x 10(-8) to 1 x 10(-4) M. For each concentration we measured the average fluorescence as determined by flow cytometry, the extent of BrdU substitution and the effect of the BrdU on cell growth. We determined that a BrdU concentration of 1 x 10(-5) M resulted in sufficient substitution to quench the fluorescence from 33258 Hoechst by a factor of 4, allowing discrimination between cycling and noncycling cells. The extent of BrdU substitution after growth for 24 hr in this concentration of BrdU was 64%. These data indicate the feasibility of detecting deoxyribonucleic acid synthesis in whole cells using the 33258 Hoechst-BrdU methodology.

Preparation and flow cytometric analysis of metaphase chromosomes of tomato

1991 ◽  
Vol 82 (1) ◽  
pp. 101-111 ◽  
Author(s):  
K. Arumuganathan ◽  
J. P. Slattery ◽  
S. D. Tanksley ◽  
E. D. Earle
Keyword(s):  
Flow Cytometric Analysis ◽  
Metaphase Chromosomes ◽  
Flow Cytometric

scholarly journals Modeling cell survival and change in amount of DNA during protracted irradiation

2016 ◽  
Vol 58 (3) ◽  
pp. 302-312 ◽  
Author(s):  
Yusuke Matsuya ◽  
Kaori Tsutsumi ◽  
Kohei Sasaki ◽  
Yuji Yoshii ◽  
Takaaki Kimura ◽  
...  
Keyword(s):  
Low Dose ◽  
Dose Range ◽  
Flow Cytometric Analysis ◽  
Chinese Hamster ◽  
Clonogenic Survival ◽  
High Dose ◽  
X Rays ◽  
Theoretical Evaluation ◽  
Flow Cytometric ◽  
M Phase

Abstract Hyper-radiosensitivity (HRS) is a well-known bioresponse under low-dose or low-dose-rate exposures. Although disorder of the DNA repair function, non-targeted effects and accumulation of cells in G2 have been experimentally observed, the mechanism for inducing HRS by long-term irradiation is still unclear. On the basis of biological experiments and a theoretical study, we have shown that change in the amount of DNA associated with accumulation of cells in G2 enhances radiosensitivity. To demonstrate continuous irradiation with 250 kVp X-rays, we adopted a fractionated regimen of 0.186 or 1.00 Gy per fraction at intervals of 1 h (i.e. 0.186 Gy/h, 1.00 Gy/h on average) to Chinese Hamster Ovary (CHO)-K1 cells. The change in the amount of DNA during irradiation was quantified by flow cytometric analysis with propidium iodide (PI). Concurrently, we attempted a theoretical evaluation of the DNA damage by using a microdosimetric-kinetic (MK) model that was modified to incorporate the change in the amount of DNA. Our experimental results showed that the fraction of the cells in G2/M phase increased by 6.7% with 0.186 Gy/h and by 22.1% with 1.00 Gy/h after the 12th irradiation. The MK model considering the change in amount of DNA during the irradiation exhibited a higher radiosensitivity at a high dose range, which could account for the experimental clonogenic survival. The theoretical results suggest that HRS in the high dose range is associated with an increase in the total amount of DNA during irradiation.

Root tip cell cycle synchronization and metaphase-chromosome isolation suitable for flow sorting in common wheat (Triticum aestivum L.)

Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 633-638 ◽  
Author(s):  
Jai-Heon Lee ◽  
K. Arumuganathan ◽  
Y. Yen ◽  
S. Kaeppler ◽  
H. Kaeppler ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Common Wheat ◽  
Univariate Analysis ◽  
Flow Cytometric Analysis ◽  
Root Tip ◽  
Bivariate Analysis ◽  
Root Tips ◽  
Metaphase Chromosomes ◽  
Cell Cycle Synchronization ◽  
Flow Cytometric

An efficient procedure for cell-cycle synchronization in meristematic root tips was achieved in common wheat. Treatment parameters for synchronizing the cell cycle of root tip meristem cells, such as time-course and applied concentrations of various chemicals, were systematically tested and optimized by flow cytometric analysis of isolated nuclei. High mitotic indices (69.5% in the root tip meristematic area) were routinely obtained by treating germinating seeds with 1.25 mM hydroxyurea for 16 h, followed by incubation in a hydroxyurea-free solution for 2 h, and treatment with 1 μM trifluralin for 4 h. Uniform seed germination prior to treatment is very important for achieving consistently high metaphase indices in the root tips. Large numbers of metaphase chromosomes, suitable for flow cytometric analysis and sorting, were isolated from synchronized root tip cells. Flow sorted wheat chromosomes, via univariate and bivariate analysis, showed four major chromosome peaks. Each discrete peak may represent wheat chromosome types with similar DNA content. Bivariate flow karyotyping based on AT and GC content did not improve the separation of wheat chromosomes.Key words: flow cytometry, trifluralin, hydroxyurea, univariate analysis, bivariate analysis.

scholarly journals Actin-based myosin XXI (13) molecular motor is involved in early phase of Leishmania cytokinesis

2021 ◽  
Author(s):  
Rani Bajaj ◽  
Chhitar M. Gupta
Keyword(s):  
Cell Division ◽  
Cell Growth ◽  
Molecular Motor ◽  
Flow Cytometric Analysis ◽  
Microscopic Analysis ◽  
Cell Division Cycle ◽  
Significant Delay ◽  
Initiation Phase ◽  
Flow Cytometric ◽  
Tail Structure

AbstractLeishmania genome encodes for two isoforms of myosin, but only Myosin XXI (Myo21), which is a novel form of myosin in that it contains two ubiquitin associated-like (UBA) domains towards the end of its tail structure, is expressed in both the promastigote and amastigote forms of this protozoan. Earlier studies have shown that in Leishmania promastigotes Myo21 besides localizing throughout the cell body and flagellum, it is prominently localized to the base of the flagellum. It has further been shown that this protein in the promastigotes plays an important role in regulating the cell morphology, motility, flagellum dynamics, growth and intracellular trafficking, As Myo21 depletion has been shown to result in reduced cell growth in culture, we considered it of interest to investigate whether the observed effect of Myo21 on the cell growth is mediated through its possible role in Leishmania cell division cycle. For this, we prepared heterozygous Myo21 mutants of Leishmania promastigotes (Myo21+/−cells) and then analyzed their morphology, growth and cell division cycle, using wild type Leishmania promastigotes (Myo21+/+ cells) as control. The cell division cycle was analyzed by employing flow cytometry and immunofluorescence microscopy. Flow cytometric analysis revealed that the G2/M to G1 phase transition in Myo21+/− cell is significantly delayed, as compared to Myo21+/+ cells. Immunofluorescence confocal microscopic analysis indicated that Myo21+/− cells encountered a significant delay in initiation of cytokinesis, which was mainly due to delay in the flagellar pocket division. Further analysis revealed that actin-based Myo21 motor is essentially required in the initiation phase of Leishmania cytokinesis.

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