scholarly journals Cytogenetic events in the endosperm of amphiploidAvena maroccana×A. longiglumis

2021 ◽  
Author(s):  
Paulina Tomaszewska ◽  
Romuald Kosina
Keyword(s):  
Cell Cycle ◽  
Wild Species ◽  
Repetitive Sequences ◽  
Spatial Arrangement ◽  
Modal Number ◽  
Intergenomic Translocations ◽  
C Genome ◽  
Concentric Pattern

AbstractThis study analysed cytogenetic events occurring in the syncytial endosperm of theAvena maroccanaGand. ×Avena longiglumisDur. amphiploid, which is a product of two wild species having different genomes. Selection through the elimination of chromosomes and their fragments, including those translocated, decreased the level of ploidy in the endosperm below the expected 3n, leading to the modal number close to 2n. During intergenomic translocations, fragments of the heterochromatin-rich C-genome were transferred to the A and Al genomes. Terminal and non-reciprocal exchanges dominated, whereas other types of translocations, including microexchanges, were less common. Using two probes and by counterstaining with DAPI, theA. longiglumisand the rare exchanges between the A and Al genomes were detected by GISH. The large discontinuity in the probe labelling in the C chromosomes demonstrated inequality in the distribution of repetitive sequences along the chromosome and probable intragenomic rearrangements. In the nucleus, the spatial arrangement of genomes was non-random and showed a sectorial-concentric pattern, which can vary during the cell cycle, especially in the less stable tissue like the hybrid endosperm.

scholarly journals Cytogenetic events in the endosperm of amphiploid Avena magna × A. longiglumis

2021 ◽  
Author(s):  
Paulina Tomaszewska ◽  
Romuald Kosina
Keyword(s):  
Cell Cycle ◽  
Wild Species ◽  
Repetitive Sequences ◽  
Spatial Arrangement ◽  
Modal Number ◽  
Intergenomic Translocations ◽  
C Genome ◽  
Concentric Pattern

AbstractThis study analysed cytogenetic events occurring in the syncytial endosperm of the Avena magna H. C. Murphy & Terrell × Avena longiglumis Durieu amphiploid, which is a product of two wild species having different genomes. Selection through the elimination of chromosomes and their fragments, including those translocated, decreased the level of ploidy in the endosperm below the expected 3n, leading to the modal number close to 2n. During intergenomic translocations, fragments of the heterochromatin-rich C-genome were transferred to the D and Al genomes. Terminal and non-reciprocal exchanges dominated, whereas other types of translocations, including microexchanges, were less common. Using two probes and by counterstaining with DAPI, the A. longiglumis and the rare exchanges between the D and Al genomes were detected by GISH. The large discontinuity in the probe labelling in the C chromosomes demonstrated inequality in the distribution of repetitive sequences along the chromosome and probable intragenomic rearrangements. In the nucleus, the spatial arrangement of genomes was non-random and showed a sectorial-concentric pattern, which can vary during the cell cycle, especially in the less stable tissue like the hybrid endosperm.

GENOMES OF THE AUSTRALIAN WILD SPECIES OF COTTON. I. GOSSYPIUM STURTIANUM, THE STANDARD FOR THE C GENOME

1979 ◽  
Vol 21 (3) ◽  
pp. 363-366 ◽  
Author(s):  
G. Allan Edwards
Keyword(s):  
Wild Species ◽  
C Genome ◽  
Total Complement

A detailed karyotype of Gossypium sturtianum Willis is presented to establish the C genome karyotype for comparison with other Australian wild species of cotton. Gossypium sturtianum has one chromosome with a median centromere, eight with slightly submedian centromeres, two with submedian centromeres and two with highly submedian centromeres. Chromosomes 8 and 9 have satellites. The total complement length is 75.04 micrometers.

scholarly journals Chromosome condensation and sister chromatid pairing in budding yeast.

1994 ◽  
Vol 125 (3) ◽  
pp. 517-530 ◽  
Author(s):  
V Guacci ◽  
E Hogan ◽  
D Koshland
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Repetitive Sequences ◽  
Cell Cycle Regulators ◽  
Mitotic Chromosomes ◽  
Rdna Cluster ◽  
Unique Region ◽  
Artificial Chromosomes ◽  
Fish Method ◽  
Sister Chromatids

We have developed a fluorescent in situ hybridization (FISH) method to examine the structure of both natural chromosomes and small artificial chromosomes during the mitotic cycle of budding yeast. Our results suggest that the pairing of sister chromatids: (a) occurs near the centromere and at multiple places along the chromosome arm as has been observed in other eukaryotic cells; (b) is maintained in the absence of catenation between sister DNA molecules; and (c) is independent of large blocks of repetitive DNA commonly associated with heterochromatin. Condensation of a unique region of chromosome XVI and the highly repetitive ribosomal DNA (rDNA) cluster from chromosome XII were also examined in budding yeast. Interphase chromosomes were condensed 80-fold relative to B form DNA, similar to what has been observed in other eukaryotes, suggesting that the structure of interphase chromosomes may be conserved among eukaryotes. While additional condensation of budding yeast chromosomes were observed during mitosis, the level of condensation was less than that observed for human mitotic chromosomes. At most stages of the cell cycle, both unique and repetitive sequences were either condensed or decondensed. However, in cells arrested in late mitosis (M) by a cdc15 mutation, the unique DNA appeared decondensed while the repetitive rDNA region appeared condensed, suggesting that the condensation state of separate regions of the genome may be regulated differently. The ability to monitor the pairing and condensation of sister chromatids in budding yeast should facilitate the molecular analysis of these processes as well as provide two new landmarks for evaluating the function of important cell cycle regulators like p34 kinases and cyclins. Finally our FISH method provides a new tool to analyze centromeres, telomeres, and gene expression in budding yeast.

GENOMES OF THE AUSTRALIAN WILD SPECIES OF COTTON. II. THE DESIGNATION OF A NEW G GENOME FOR GOSSYPIUM BICKII

1979 ◽  
Vol 21 (3) ◽  
pp. 367-372 ◽  
Author(s):  
G. Allan Edwards ◽  
M. Anwar Mirza
Keyword(s):  
Dna Content ◽  
Wild Species ◽  
Seed Proteins ◽  
Chromosome Size ◽  
Phenetic Analysis ◽  
Genome Species ◽  
Clear Separation ◽  
Leucine Aminopeptidases ◽  
C Genome ◽  
Secondary Constrictions

Gossypium bickii Prokh. is distinct from the C genome species, although it was tentatively placed in this genome. A comparison of the karyotypes of G. bickii and G. sturtianum Willis separates G. bickii sharply from G. sturtianum, the standard species for the C genome. Karyotypic differences are evident in centromere position of the chromosomes, chromosome size, and the lack of satellites or secondary constrictions in G. bickii. A clear separation of G. bickii from G. sturtianum and other Gossypium species is also demonstrated in previous studies of phenetic analysis, flower flavonoids, DNA content, and electrophoresis of seed proteins, esterases, leucine aminopeptidases, and catalases. G. bickii is placed in a new G genome and is assigned to the 2G1 subgenome.

Genomic in situ hybridization differentiates between A/D- and C-genome chromatin and detects intergenomic translocations in polyploid oat species (genus Avena)

Genome ◽  
1994 ◽  
Vol 37 (4) ◽  
pp. 613-618 ◽  
Author(s):  
E. N. Jellen ◽  
B. S. Gill ◽  
T. S. Cox
Keyword(s):  
In Situ Hybridization ◽  
Avena Sativa ◽  
Genomic In Situ Hybridization ◽  
Hybridization Pattern ◽  
C Banding ◽  
Intergenomic Translocations ◽  
C Genome ◽  
Total Dna

The genomic in situ hybridization (GISH) technique was used to discriminate between chromosomes of the C genome and those of the A and A/D genomes in allopolyploid oat species (genus Avena). Total biotinylated DNA from A. strigosa (2n = 2x = 14, AsAs genome) was mixed with sheared, unlabelled total DNA from A. eriantha (2n = 2x = 14, CpCp) at a ratio of 1:200 (labelled to unlabelled). The resulting hybridization pattern consisted of 28 mostly labelled and 14 mostly unlabelled chromosomes in the hexaploids. Attempts to discriminate between chromosomes of the A and D genomes in A. sativa (2n = 6x = 42, AACCDD) were unsuccessful using GISH. At least eight intergenomic translocation segments were detected in A. sativa 'Ogle', several of which were not observed in A. byzantina 'Kanota' (2n = 6x = 42, AACCDD) or in A. sterilis CW 439-2 (2n = 6x = 42, AACCDD). At least five intergenomic translocation segments were observed in A. maroccana CI 8330 'Magna' (2n = 4x = 28, AACC). In both 'Ogle' and 'Magna', positions of most of these translocations matched with C-banding patterns.Key words: Avena sativa, oat, in situ hybridization, C-banding, Avena macrostachya.

Fluorescence in situ hybridization mapping of Avena sativa L. cv. SunII and its monosomic lines using cloned repetitive DNA sequences

Genome ◽  
2002 ◽  
Vol 45 (6) ◽  
pp. 1230-1237 ◽  
Author(s):  
M L Irigoyen ◽  
C Linares ◽  
E Ferrer ◽  
A Fominaya
Keyword(s):  
In Situ Hybridization ◽  
Dna Sequences ◽  
Avena Sativa ◽  
Meiotic Chromosome ◽  
D Genome ◽  
Fish Mapping ◽  
Intergenomic Translocations ◽  
A Genome ◽  
C Genome

Fluorescent in situ hybridization (FISH) employing multiple probes was used with mitotic or meiotic chromosome spreads of Avena sativa L. cv. SunII and its monosomic lines to produce physical chromosome maps. The probes used were Avena strigosa pAs120a (which hybridizes exclusively to A-genome chromosomes), Avena murphyi pAm1 (which hybridizes exclusively to C-genome chromosomes), A. strigosa pAs121 (which hybridizes exclusively to A- and D-genome chromosomes), and the wheat rDNA probes pTa71 and pTa794. Simultaneous and sequential FISH employing two-by-two combinations of these probes allowed the unequivocal identification and genome assignation of all chromosomes. Ten pairs were found carrying intergenomic translocations: (i) between the A and C genomes (chromosome pair 5A); (ii) between the C and D genomes (pairs 1C, 2C, 4C, 10C, and 16C); and (iii) between the D and C genomes (pairs 9D, 11D, 13D, and 14D). The existence of a reciprocal intergenomic translocation (10C–14D) is also proposed. Comparing these results with those of other hexaploids, three intergenomic translocations (10C, 9D, and 14D) were found to be unique to A. sativa cv. SunII, supporting the view that 'SunII' is genetically distinct from other hexaploid Avena species and from cultivars of the A. sativa species. FISH mapping using meiotic and mitotic metaphases facilitated the genomic and chromosomal identification of the aneuploid chromosome in each monosomic line. Of the 18 analyzed, only 11 distinct monosomic lines were actually found, corresponding to 5 lines of the A genome, 2 lines of the C genome, and 4 lines of the D genome. The presence or absence of the 10C–14D interchange was also monitored in these lines.Key words: Avena sativa, monosomics, FISH mapping, genomic identification, intergenomic translocations.

Temporal order of gene replication in Chinese hamster ovary cells

1989 ◽  
Vol 9 (7) ◽  
pp. 2881-2889
Author(s):  
J Taljanidisz ◽  
J Popowski ◽  
N Sarkar
Keyword(s):  
Cell Cycle ◽  
Nuclear Dna ◽  
Chinese Hamster Ovary Cells ◽  
Repetitive Sequences ◽  
Chinese Hamster ◽  
Nuclear Dna Content ◽  
Single Copy ◽  
S Phase ◽  
Specific Gene ◽  
Cell Permeabilization

To investigate the molecular basis of the regulatory mechanisms responsible for the orderly replication of the mammalian genome, we have developed an experimental system by which the replication order of various genes can be defined with relative ease and precision. Exponentially growing CHO-K1 cells were separated into populations representing various stages of the cell cycle by centrifugal elutriation and analyzed for cell cycle status flow cytometry. The replication of specific genes in each elutriated fraction was measured by labeling with 5-mercuri-dCTP and [3H]dTPP under conditions of optimal DNA synthesis after cell permeabilization with lysolecithin. Newly synthesized mercurated DNA from each elutriated fraction was purified by affinity chromatography on thiol-agarose and replicated with the large fragment of Escherichia coli DNA polymerase I by using [alpha-32P]dATP and random primers. The 32P-labeled DNA representative of various stages of the cell cycle was then hybridized with dot blots of plasmid DNA containing specific cloned genes. From these results, it was possible to deduce the nuclear DNA content at the time each specific gene replicated during S phase (C value). The C values of 29 genes, which included single-copy genes, multifamily genes, oncogenes, and repetitive sequences, were determined and found to be distributed over the entire S phase. Of the 28 genes studied, 19 had been examined by others using in vivo labeling techniques, with results which agreed with the replication pattern observed in this study. The replication times of nine other genes are described here for the first time. Our method of analysis is sensitive enough to determine the replication time of single-copy genes. The replication times of various genes and their levels of expression in exponentially growing CHO cells were compared. Although there was a general correlation between transcriptional activity and replication in the first half of S phase, examination of specific genes revealed a number of exceptions. Approximately 25% of total poly(A) RNA was transcribed from the late-replicating DNA.

scholarly journals CELL CONTACT DEPENDENCE OF SURFACE GALACTOSYLTRANSFERASE ACTIVITY AS A FUNCTION OF THE CELL CYCLE

1974 ◽  
Vol 63 (3) ◽  
pp. 796-805 ◽  
Author(s):  
Glenda C. Webb ◽  
Stephen Roth
Keyword(s):  
Cell Cycle ◽  
Normal Cell ◽  
Spatial Arrangement ◽  
The Other ◽  
Cell Contact ◽  
Transferase Activity ◽  
Intercellular Contact ◽  
Malignant Cells ◽  
Cell Type ◽  
3T3 Cells

Mitotic, nonmalignant Balb/c 3T3 cells exhibit endogenous, surface galactosyltransferase activity that does not require intercellular contact throughout the assay period. In this respect, mitotic 3T3 cells resemble malignant Balb/c 3T12 cells which similarly show no contact requirement for optimum transferase activity in any phase of their cell cycle. Previously, it was shown that randomly growing populations of 3T3 cells have lower galactosyltransferase activity when assayed under conditions which decreased cell contact. This led to the conclusion that these normal (3T3) and malignant (3T12) cells differed in that intercellular contact is required for optimum activity of surface galactosyltransferases on the normal cell type. The present data indicate that mitotic 3T3 cells may be capable of expressing enzyme activities exhibited at all times by malignant cells. That is, mitotic 3T3 cells and randomly growing 3T12 cells may readily catalyze galactosyltransferase reactions between enzymes and acceptors on the same cell. Interphase 3T3 cells, on the other hand, might require that enzymes glycosylate acceptors on adjacent cells. A model is proposed that suggests that changes in the spatial arrangement of surface enzymes and acceptors or variations in the fluidity of the cell membrane can account for this contact-related glycosylation.

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