Formaldehyde-induced acentric chromosome fragments and chromosome stickiness inChortophaga neuroblasts

1986 ◽  
Vol 8 (3) ◽  
pp. 401-411 ◽  
Author(s):  
Mary Ann Dowd ◽  
Mary Esther Gaulden ◽  
Bertha L. Proctor ◽  
G. Burton Seibert
Keyword(s):  
Chromosome Fragments ◽  
Chromosome Stickiness

scholarly journals Meiotic arrest compromises pollen fertility in an interspecific hybrid between Brachiaria ruziziensis x Brachiaria decumbens (Poaceae: paniceae)

2007 ◽  
Vol 50 (5) ◽  
pp. 831-837 ◽  
Author(s):  
Andréa Beatriz Mendes-Bonato ◽  
Maria Suely Pagliarini ◽  
Cacilda Borges do Valle
Keyword(s):  
Interspecific Hybrid ◽  
Pollen Grains ◽  
Pollen Sterility ◽  
Pollen Wall ◽  
Brachiaria Decumbens ◽  
Brachiaria Ruziziensis ◽  
Chromosome Fragments ◽  
Total Pollen ◽  
Chromosome Stickiness ◽  
Metaphase I

Microsporogenesis was analyzed in an interspecific hybrid between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (2n=4x=36) and a natural apomictic tetraploid accession of B. decumbens. Syncytes involving a large number of cells were recorded in 15.4% of meiocytes. Meiosis progressed normally in syncytes during prophase I; in metaphase I, however, several nuclei were found fusioned, showing chromosome stickiness and several chromosome fragments. Meiosis was arrested in metaphase I and pycnotic nuclei and micronuclei were formed. Abnormal cytokinesis fractionated the syncyte into abnormal meiotic products that were covered by the pollen wall. Meiocytes in leptotene were recorded in all the slides prepared for both meiotic divisions, and abnormal "pollen grains" with well-developed pollen wall but containing leptotene nuclei were recorded in 9.18% of grains analyzed. These findings suggested that the meiocytes received the signal to enter meiosis but lacked the signal to proceed beyond leptotene. Despite the absence of the meiotic process, such cells were covered by pollen grain wall. Total pollen sterility resulted from these abnormalities combined with still others observed among meiocytes.

scholarly journals GAMMA RAY - INDUCED MITOTIC ABNORMALITIES IN Helianthus annuus L. VARIETY EKIZ 1 / LOS RAYOS DE GAMMA CAUSA ANORMALIDADES MITOTICAS EN Helianthus annuus L. VARIEDAD DE EKIZ 1 / LES ANORMALITÉS MITOTIQUES CHARGÉÉS DES RAYONS GAMMA

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 39-46
Author(s):  
Orhan Arslan ◽  
Şenol Bal ◽  
Nilgün Venice ◽  
Semra Mirici
Keyword(s):  
Helianthus Annuus ◽  
Mitotic Index ◽  
Gamma Rays ◽  
Metaphase Chromosome ◽  
Gamma Ray ◽  
Dose Increase ◽  
Helianthus Annuus L ◽  
Mitotic Abnormalities ◽  
Chromosome Stickiness

SUMMARYIn this study, mitotic effects of gamma rays on Ekiz 1 variety belonging to Helianthus annuus L. (2n= 34) in the M0 (first irradiated seeds), M1 and M2 generations have been investigated. Seeds (M0) were irradiated with gamma rays at 10, 20, 30, 40 and 50 kR doses. Percentage of total abnormalities in the M0, M1 and M2 generations increased parallel to the increasing dose of radiation. These abnormalites have been observed as C-metaphase, chromosome stickiness, laggards and bridges with or without fragment. Mitotic index (M.I.) in the M0, M1 and M2 generations has decreased parallel to the dose increase. When the generations are compared, both the amounts of decrease in mitotic index and in the percentage of mitotic abnormalities were mostly observed in M0.

Generation of sequence-tagged sites from Xp22.3 by isolating commonAlu-PCR products of radiation hybrids retaining overlapping human X chromosome fragments

1996 ◽  
Vol 97 (5) ◽  
pp. 604-610 ◽  
Author(s):  
I. A. Glass ◽  
M. Passage ◽  
L. Bernatowicz ◽  
E. C. Salido ◽  
T. Mohandas ◽  
...  
Keyword(s):  
X Chromosome ◽  
Sequence Tagged Sites ◽  
Radiation Hybrids ◽  
Pcr Products ◽  
Chromosome Fragments

scholarly journals Chromosome-Encoded Class D β-Lactamase OXA-23 in Proteus mirabilis

2002 ◽  
Vol 46 (6) ◽  
pp. 2004-2006 ◽  
Author(s):  
R. Bonnet ◽  
H. Marchandin ◽  
C. Chanal ◽  
D. Sirot ◽  
R. Labia ◽  
...  
Keyword(s):  
Teaching Hospital ◽  
Proteus Mirabilis ◽  
Molecular Typing ◽  
Clinical Isolates ◽  
Clonal Strain ◽  
Class D ◽  
Chromosome Fragments

ABSTRACT Ten nonrepetitive Proteus mirabilis isolates, which were collected over 4 years (1996 to 1999) at the teaching hospital of Clermont-Ferrand, France, produced class D carbapenemase OXA-23. MICs of imipenem were 0.25 to 0.5 μg/ml for these clinical isolates. Molecular typing revealed that the 10 P. mirabilis isolates originated from the same clonal strain. Hybridization of I-CeuI-generated chromosome fragments with a bla OXA-23 probe showed that the gene was chromosome encoded in the P. mirabilis strain.

Chromosome Fragments and Mutation of the Incompatibility Gene

Nature ◽  
1961 ◽  
Vol 190 (4780) ◽  
pp. 990-991 ◽  
Author(s):  
D. LEWIS
Keyword(s):  
Chromosome Fragments

scholarly journals Action of taxol on mitosis: modification of microtubule arrangements and function of the mitotic spindle in Haemanthus endosperm.

1983 ◽  
Vol 96 (2) ◽  
pp. 527-540 ◽  
Author(s):  
J Molè-Bajer ◽  
A S Bajer
Keyword(s):  
Equatorial Region ◽  
Polar Regions ◽  
Higher Plant ◽  
Chromosome Fragments ◽  
Immunocytochemical Method ◽  
And Function ◽  
Spindle Function ◽  
Direction Opposite

We have studied the effect of taxol on mitosis in Haemanthus endosperm. Immuno-Gold Stain (IGS), a new immunocytochemical method (17), was used to visualize microtubules (MTs) in the light microscope. Observations on MT arrangements were correlated with studies in vivo. Chromosome movements are affected in all stages of mitosis which progresses over at least 10(4) range of taxol concentrations. The three most characteristic effects on MTs are: (a) enhancement of the lateral associations between MTs, seen especially during the reorganization of the polar region of the spindle, (b) promotion of MT assembly, leading to the formation of additional MTs in the spindle and MT arrays in the cytoplasm, and (c) an increase in MT stability, demonstrated in their increased cold resistance. In this report, the emphasis is on the primary, immediate effects, occurring in the first 30 min of taxol action. Effects are detected after a few mins, are reversible, and are concentration/time dependent. The spindle and phragmoplast are remarkably modified due to the enhancement of lateral associations of MTs and the formation of abundant nonkinetochore and polar, asterlike MTs. The equatorial region of the interzone in anaphase may be entirely depleted of MTs, and the spindle may break perpendicular to the spindle axis. Mitosis is completed in these conditions, providing evidence for the motile autonomy of each half-spindle. Trailing chromosome arms in anaphase are often stretched and broken. Chromosome fragments are transported away from the polar regions, i.e., in the direction opposite to that expected (5, 6). This supplies the first direct evidence of pushing by elongating MTs in an anastral higher plant spindle. These observations draw attention to the relation between the lateral association of MT ends to assembly/disassembly and to the role of such an interaction in spindle function and organization.

Mouse one-cell embryos undergoing a radiation-induced G2 arrest may re-enter S-phase in the absence of cytokinesis

2002 ◽  
Vol 80 (7) ◽  
pp. 618-624 ◽  
Author(s):  
P Jacquet ◽  
J Buset ◽  
J Vankerkom ◽  
S Baatout ◽  
L de Saint-Georges ◽  
...  
Keyword(s):  
Calyculin A ◽  
Embryonic Cells ◽  
G2 Arrest ◽  
Cell Stage ◽  
Chromosome Fragments ◽  
X Irradiation ◽  
Radiation Induced ◽  
Mouse Zygotes ◽  
The One

PCC (premature chromosome condensation) can be used for visualizing and scoring damage induced by radiation in the chromatin of cells undergoing a G1 or G2 arrest. A method involving the fusion of irradiated single embryonic cells with single MI oocytes was used to induce PCC in mouse zygotes of the BALB/c strain, which suffer a drastic G2 arrest after X-irradiation (dose used 2.5 Gy). Other G2-arrested embryos were exposed in vitro to the phosphatase inhibitor calyculin A. Both methods furnished excellent chromosome preparations of the G2-arrested embryos. The mean number of chromosome fragments did not change significantly during G2 arrest, suggesting that zygotes of this strain are unable to repair DNA damage leading to such aberrations. Forty to fifty percent of the irradiated embryos were unable to cleave after G2 arrest and remained blocked at the one-cell stage for a few days before dying. PCC preparations obtained from such embryos suggested that about 30% of them had undergone a late mitosis not followed by cytokinesis and had entered a new DNA synthesis. These results are discussed in the light of recent observations in irradiated human cells deficient in the p53/14-3-3sigma pathway.Key words: PCC, embryo, oocyte, calyculin A, G2 arrest, cytokinesis.

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