Number Of Metaphase Chromosomes Research Articles

Astragalus stenosemioides (Fabaceae)’in karyotip analizi

In this research the metaphase chromosome number and karyotype of Astragalus stenosemioides species growing naturally in Turkey are studied. The study revealed that the chromosome number of A. stenosemioides is 2n = 16. The basic chromosome number of species is determined as x = 8. The karyotype formula of A. stenosemioides is 8m. The total length of the somatic chromosomes of A. stenosemioides ranges between 1.96 - 3.38 μm. The total haploid chromosome length of A. stenosemioides is determined as 21.36 μm. In addition, the karyotype asymmetry of the species was evaluated by different methods; Stebbins classification, TF%, AsK%, Syi and Rec, A1, A2, DI, A, and AI.

Generation of microdissected DNA probes from metaphase chromosomes when chromosome identification by routine staining is impossible.

Application of microdissected DNA libraries and DNA probes in numerous and various modern molecular cytogenetic studies showed them as an efficient and reliable tool in the analysis of chromosome reorganization during karyotypic evolution and in the diagnosis of human chromosome pathology. An important advantage of DNA probe generation by metaphase chromosome microdissection followed by sequence-independent polymerase chain reaction in comparison with the method of DNA probe generation using chromosome sorting is the possibility of DNA probe preparation from chromosomes of an individual sample without cell line establishment for the production of a large number of metaphase chromosomes. One of the main requirements for successful application of this technique is a possibility for identification of the chromosome of interest during its dissection and collection of its material from metaphase plates spread on the coverslip. In the present study, we developed and applied a technique for generation of microdissected DNA probes in the case when chromosome identification during microdissection appeared to be impossible. The technique was used for generation of two sets of Whole Chromosome Paints (WCPs) from all chromosomes of two species of free-living flatworms in the genus Macrostomum, M. mirumnovem and M. cliftonensis. The single-copy chromosome technique including separate collection of all chromosomes from one metaphase plate allowed us to generate WCPs that painted specifically the original chromosome by Chromosome In Situ Suppression Hybridization (CISS-Hybridization). CISS-Hybridization allowed identifying the original chromosome(s) used for DNA probe generation. Pooled WCPs derived from homologous chromosomes increased the intensity and specificity of chromosome painting provided by CISS-Hybridization. In the result, the obtained DNA probes appeared to be good enough for application in our studies devoted to analysis of karyotypic evolution in the genus Macrostomum and for analysis of chromosome rearrangements among the worms of laboratory cultures of M. mirumnovem.

Chromosomal characterization based on repetitive DNA distribution in a tetraploid cytotype of Chrysanthemum zawadskii

The aim of this study was to gain insight into the basic genetics of Chrysanthemum zawadskii Herbich ssp. lucidum (NAK.) Y. Lee, a Chrysanthemum subspecies from Ulleung Island, South Korea, by investigating its karyotypic and cytogenetic characteristics, and to contribute to the karyosystematic study of the genus Chrysanthemum (tribe: Anthemideae). Fluorescence in situ hybridization (FISH) was used to characterize the ploidy level, chromosome constitution, and distribution of 5S and 18S ribosomal DNA (rDNA) and Arabidopsis-type telomere repeats (TTTAGGG)n in C. zawadskii ssp. lucidum chromosomes. The somatic metaphase chromosome number of C. zawadskii ssp. lucidum was tetraploid (2n = 4x = 36). Signals from four 5S rDNA loci were detected in the middle of the long arms of some chromosomes, whereas signals from eight 18S rDNA loci were located at the termini of the short arms. The two rDNA markers localized to different chromosomes with no co-localization. The Arabidopsis-type telomeric repeats, however, co-localized with 18S rDNA sites at the ends of both chromosomal arms. This co-localization of telomeric sequences and 18S rDNA has also been observed in other Chrysanthemum species with various levels of ploidy, indicating that it is a general feature of the genus. DAPI (4′,6-diamidino-2-phenylindole) bands incidentally detected after FISH are also illustrated. These preliminary data contribute towards understanding the karyotypic trends and role of polyploidy in the evolution of the genus Chrysanthemum.

Chromosome analysis of arsenic affected cattle

Aim: The aim was to study the chromosome analysis of arsenic affected cattle. Materials and Methods: 27 female cattle (21 arsenic affected and 6 normal) were selected for cytogenetical study. The blood samples were collected, incubated, and cultured using appropriate media and specific methods. The samples were analyzed for chromosome number and morphology, relative length of the chromosome, arm ratio, and centromere index of X chromosome and chromosomal abnormalities in arsenic affected cattle to that of normal ones. Results: The diploid number of metaphase chromosomes in arsenic affected cattle as well as in normal cattle were all 2n=60, 58 being autosomes and 2 being sex chromosomes. From the centromeric position, karyotyping studies revealed that all the 29 pair of autosomes was found to be acrocentric or telocentric, and the sex chromosomes (XX) were submetacentric in both normal and arsenic affected cattle. The relative length of all the autosome pairs and sex chrosomosome pair was found to be higher in normal than that of arsenic affected cattle. The mean arm ratio of X-chromosome was higher in normal than that of arsenic affected cattle, but it is reverse in case of centromere index value of X-chromosome. There was no significant difference of arm ratio and centromere index of X-chromosomes between arsenic affected and normal cattle. No chromosomal abnormalities were found in arsenic affected cattle. Conclusion: The chromosome analysis of arsenic affected cattle in West Bengal reported for the first time in this present study which may serve as a guideline for future studies in other species. These reference values will also help in comparison of cytological studies of arsenic affected cattle to that of various toxicants.

정선황기의 세포유전학적 연구

This study was carried out to determine the karyotype and chromosomal localizations of 45S and 5S rDNAs using FISH in Astragalus koraiensis. The somatic metaphase chromosome number of this species was 2n

P300-mediated acetylation of TRF2 is required for maintaining functional telomeres

The human telomeric protein TRF2 is required to protect chromosome ends by facilitating their organization into the protective capping structure. Post-translational modifications of TRF2 such as phosphorylation, ubiquitination, SUMOylation, methylation and poly(ADP-ribosyl)ation have been shown to play important roles in telomere function. Here we show that TRF2 specifically interacts with the histone acetyltransferase p300, and that p300 acetylates the lysine residue at position 293 of TRF2. We also report that p300-mediated acetylation stabilizes the TRF2 protein by inhibiting its ubiquitin-dependent proteolysis and is required for efficient telomere binding of TRF2. Furthermore, overexpression of the acetylation-deficient mutant, K293R, induces DNA-damage response foci at telomeres, thereby leading to induction of impaired cell growth, cellular senescence and altered cell cycle distribution. A small but significant number of metaphase chromosomes show no telomeric signals at chromatid ends, suggesting an aberrant telomere structure. These findings demonstrate that acetylation of TRF2 by p300 plays a crucial role in the maintenance of functional telomeres as well as in the regulation of the telomere-associated DNA-damage response, thus providing a new route for modulating telomere protection function.

Cytogenetic Study of Maackia amurensis Rupr. & Maxim. And M. fauriei(Levl.) Takeda Using Karyotyping Analysis and the FISH Technique

Chromosome analysis using karyotyping and bicolor FISH were carried out for two Maackia species (M. fauriei and M. amurensis) found in Korea. The somatic metaphase chromosome number was 2n = 2x = 18 in both, and the size of these chromosomes ranged from 3.58 to 5.82 . The chromosome complements consisted of two pairs of metacentric (chromosomes 1 and 7), four pairs of submetacentrics (chromosomes 4, 6, 8 and 9) and three pairs of subtelocentrics (chromosomes 2, 3 and 5) in M. fauriei but, chromosomes 4 (subtelocentric) and 7 (submetacentric) of M. amurensis have different morphology. Using bicolor FISH, a pair of 45S rDNA loci were observed for both M. fauriei and M. amurensis, but the number and site of the 5S rDNA signal were different in the two species. M. fauriei has two pairs of 5S signals on chromosomes 7 and 8 but, M. amurensis has four paris on chromosomes 3, 4, 7 and 7. Hence, the 5S rDNA is a useful FISH for Maackia species.

Chromosomal studies of three species of Bidens (L.) (Asteraceae)

AbstractThe chromosomal numbers of three species of Bidens were determined based on an analysis of somatic metaphases. The species studied were Bidens pilosa L., Bidens subalternans DC and Bidens alba (L.) DC, all of which belong to the Bidens pilosa species complex. The three species have a similar morphology: Bidens pilosa and B. subalternans are widely distributed in agricultural areas, in disturbed habitats and along roadsides, whereas B. alba occurs only along the seacoast. Bidens pilosa has 2n = 72 and B. subalternans and B. alba has 2n = 48. These numbers agreed with the basic chromosomal number of n = 12 reported for the tribe Heliantheae and show that the number of metaphase chromosomes can be used to distinguish Bidens pilosa from the other two species of the B. pilosa complex in southeastern Brazil.

Evaluation of the colchicine-like activity of Gloriosa superba-extracted fractions for mosquito (Diptera: Culicidae) cytogenetic study.

Four fractions of Gloriosa superba L., i.e., hexane fraction, dichloromethane fraction 1, dichloromethane fraction 2, and methanol fraction, were investigated for colchicine-like activity using a mosquito cytogenetic assay. The results revealed that the latter three fractions yielded promisingly high colchicine-like activity, whereas the hexane fraction yielded very low activity compared with 1% colchicine in a 0.85% sodium chloride solution. The metaphase rates and average number of metaphase chromosomes per positive brain ganglion (range) of Aedes aegypti L. larvae after incubation with 0.25-2% solutions of dichloromethane fraction 1, dichloromethane fraction 2, 0.5-2% solutions of methanol fraction, and 1% colchicine solution were 90-100% and 7 (2-19) to 22 (7-47); 90-100% and 4 (1-11) to 30 (4-73); 95-100% and 11 (1-28) to 17 (2-62); and 100% and 6 (2-11), respectively. The temperature stability tests of the three promising fractions were performed by heating 0.5% working solution at 121 degrees C for 15 min and preparing 0.5% working solution from stock frozen at -20 degrees C for 10 mo. These fractions also yielded satisfactory outcomes of metaphase rates and an average number of metaphase chromosomes per positive brain ganglia compared with 1% colchicine solution.

Comparative karyology, DNA methylation and restriction pattern analysis of male and female plants of the dioecious alga Chara tomentosa (Charophyceae)

Comparison of karyology, restriction patterns and DNA methylation levels (as gender separation could be related to some epigenetic mechanism, e.g. DNA methylation) has been performed between male and female individuals of the dioecious species, Chara tomentosa. In contrast to angiosperms, sex determination systems in Charophyceae have not been studied. High-performance liquid chromatography (HPLC) showed that the cytosine methylation level in female plants of Chara tomentosa reached 5·9%, while in male plants it reached 9·1%. Karyological analysis did not show any differences in metaphase chromosome number or morphology between sexes. Cytophotometric measurements of DNA content revealed differences in 1C DNA content : 7·0 pg in females and 7·4 pg in males (p < 0·001). Computer image analysis showed that in the interphase nuclei condensed chromatin consists of 34·3% of the total chromatin in female plants, while in males it was 29·6% of total chromatin (p < 0·001). Digestion of isolated DNAs with 12 enzymes showed poor enzymatic cleavage (for example with SacI) or restriction patterns which differed between the sexes (TaqI, Bst0I). The restriction endonucleases RsaI and BamHI revealed repetitive DNA families in males. BamHI generated bands of over 3000 bp while RsaI revealed populations of fragments 650–2000 bp long. DNA isolated from male individuals of C. tomentosa was less susceptible than DNA isolated from female plants to digestion with enzymes that are inhibited by methylation of dC residues (HpaII, HhaI).

Comparative karyology, DNA methylation and restriction pattern analysis of male and female plants of the dioecious alga Chara tomentosa (Charophyceae)

Comparison of karyology, restriction patterns and DNA methylation levels (as gender separation could be related to some epigenetic mechanism, e.g. DNA methylation) has been performed between male and female individuals of the dioecious species, Chara tomentosa. In contrast to angiosperms, sex determination systems in Charophyceae have not been studied. High-performance liquid chromatography (HPLC) showed that the cytosine methylation level in female plants of Chara tomentosa reached 5·9%, while in male plants it reached 9·1%. Karyological analysis did not show any differences in metaphase chromosome number or morphology between sexes. Cytophotometric measurements of DNA content revealed differences in 1C DNA content : 7·0 pg in females and 7·4 pg in males (p < 0·001). Computer image analysis showed that in the interphase nuclei condensed chromatin consists of 34·3% of the total chromatin in female plants, while in males it was 29·6% of total chromatin (p < 0·001). Digestion of isolated DNAs with 12 enzyme...

Induction of Polyploidization by Jaspamide in HL-60 Cells

Jaspamide, a natural peptide isolated from the marine sponge Hemiastrella minor, was used in the study of polyploidy in HL-60 cells. Jaspamide at 5 × 10^–8 M concentration exhibited antiproliferative activity and an increased CD4 and CD14 surface expression. After 2 days of cultivation, 56.3% of the exposed cells became multinuclear compared with 2.4% in controls. Moreover, the size and the number of nuclei of the cells increased in a time-dependent manner. An increased number of metaphase chromosomes was observed by microscopical enumeration after colcemid treatment for 60 min. The analysis of the DNA content of these cells, measured by propidium iodide staining, revealed a significant increase in the cells percentage with increased DNA content. Taken together, these findings indicate that the jaspamide treatment induces polyploidization in the HL-60 cell line.

Egg maturation and parthenogenetic recovery of diploidy in the scorpionLiocheles australasiae (Fabricius) (Scorpions, Ischnuridae)

In the scorpion Liocheles australasiae, egg maturation and parthenogenetic recoveries of chromosome number and nuclear DNA content were examined by histological, karyological observations and quantitative measurements of DNA. The primary oocyte becomes mature through two successive maturation divisions. The first maturation division takes place in the primary oocyte to produce a secondary oocyte and a first polar body. The second maturation division soon occurs in the secondary oocyte, in which the nucleus is divided into a mature egg nucleus and a second polar body nucleus, not followed by cytoplasmic fission. The first polar body, in one case, was successively divided into two second polar bodies; in the other case it was not divided. In either case, these polar bodies remained attached to the early embryo. The fate of these polar bodies during further embryogenesis were studied. In the karyological analysis, the chromosome number was divided into two groups, one from 27-32, the other was 54-64. The former was presumably the metaphase chromosome number at the meiotic division; the latter was presumably the metaphase chromosome number at the mitotic division. DNA content in the diploid nucleus of the primary oocyte, doubled before the maturation divisions, was reduced through the maturation divisions by one-half in the nuclei of the secondary oocyte and the first polar body and by one-fourth in the nuclei of the egg and the second polar bodies. The first reduction of DNA content corresponded to halving the number of the chromosomes in the first maturation division and the second to the nuclear division in the secondary oocyte. These reductions represent a common process of egg maturation, except the final production of the mature egg with two haploid nuclei, an egg nucleus, and a second polar body nucleus. These two nuclei, which were formed apart in the mature egg, drew near to fuse into a zygote nucleus. The chromosome number and nuclear DNA content were doubled in the zygote and each blastomere in embryos, supporting the hypothesis that the egg nucleus fuses with the second polar body nucleus and this conjugation initiates subsequent embryonic development.

Screening of ten plant species for metaphase chromosome preparation in adult mosquitoes (Diptera: Culicidae) using an inoculation technique.

The screening of 10 plant species (Aloe barbadensis Mill., Asparagus officinalis L., As. plumosus Bak., As. racemosus Willd., As. sprengeri Regel, Codyline fruticosa Goppert, Dracaena loureiri Gagnep., Gloriosa superba L., Hemerocallis flava L., and Sansevieria cylindrica Bojer) for colchicine-like substance(s) using a mosquito cytogenetic assay revealed that a 1% solution of dried Gl. superba rhizome extracted in 0.85% sodium chloride solution could be used instead of a 1% colchicine in Hanks' balanced salt solution. The metaphase rates and average number of metaphase chromosomes per positive mosquito of Aedes aegypti (L.) after intrathoracic inoculation with 1% Gl. superba-extracted solution were 100% and 29.80 in females, and 90% and 25.78 in males, whereas the inoculation with 1% colchicine solution yielded 100 and 90% metaphase rates, and 20.90 and 12.22 average number of metaphase chromosomes per positive mosquito in females and males, respectively. The application of Gl. superba-extracted solution for metaphase chromosome preparation in other mosquito genera and species [e.g., Culex quinquefasciatus Say, Toxorhynchites splendens (Wiedemann), and Anopheles vagus (Döenitz)] also has yielded the satisfactory results.

Cloning, characterization and chromosomal location of a satellite DNA from the Pacific oyster, Crassostrea gigas

We report the cloning and characterization of a high-copy-number, tandem-repeat satellite DNA sequence from the genome of the Pacific oyster, Crassostrea gigas (Cg). The monomeric unit was found to be 166 (±2) bp in length with 79–;94% homology between monomers of the array. The sequence is A+T-rich (60%) and lacks internal repetition and substructural features. The repeat was estimated to account for 1–;4% of the Cg genome. Fluorescence in situ hybridization (FISH) studies mapped the repeat to two distinct heterochromatic regions of two pairs of homologous chromosomes on Cg embryonic metaphases. Also, the number of metaphase chromosomes containing this repeat varied with the ploidy of the cell.

Sister-chromatid exchanges in human bronchial epithelial cells

One method of assessing the genotoxic effects of exposure to environmental agents is by determining the frequency of sister chromatid exchanges in exposed cells. In the present study, a procedure for observing sister chromatid exchanges in adult human bronchial epithelial cells exposed to a carcinogen has been developed. Using this procedure, the frequencies of sister chromatid exchanges in untreated cells from two individuals were found to be 5.1 ± 1.8 and 6.5 ± 1.4 per metaphase (mean ± SD). Cells from the first individual exposed to 7,12-dimethylbenz[ a]anthracene at 0.5, 1 and 2 μg/ml had 7.8 ± 2.2, 13 ± 3.1, 18.7 ± 3.7 sister chromatid exchanges per metaphase, respectively. This method is likely to be particularly useful for observing sister chromatid exchanges in cells that have a relatively slow growth rate in the presence of bromodeoxyuridine and for which preparation of a large number of metaphase chromosomes is difficult. In addition, the procedure provides a means of assessing genotoxic effects in the lung by examining the direct effects of pollutants on the chromosomes of the target cells for human lung cancer.

Continuous reorganization leads to extensive polymorphism in a monkey centromeric satellite

Previously we reported the existence of a highly polymorphic satellite, decasatellite, in the African green monkey genome; deca-satellite probe anneals to complex sets of repeated restriction endonuclease fragments that differ from individual to individual in the monkey population. Here we present experiments aimed at clarifying the structure and organization of deca-satellite sequences and investigating the mechanisms that generate the polymorphisms. Deca-satellite represents less than 1% of the monkey genome but the percentage varies from one monkey to another. The core sequence 5′-C-C-G-G within the ten base-pair deca-satellite repeat unit is well conserved and the central 5′-C-G is sometimes but not always methylated. Restriction endonuclease analysis with BamHI and EcoRI defines separate satellite domains that have evolved in an independent manner. In situ hybridization shows deca-satellite to be located at the centromeric regions of some but not all monkey chromosomes. This location is independently confirmed by a high frequency, in monkey libraries, of segments containing junctions between deca-satellite and α-satellite, the main monkey centromeric satellite. The total number of metaphase chromosomes that show centromeric grains after in situ hybridization with a deca-satellite probe varies from one monkey to another. Moreover, in situ hybridization to endoreduplicated diplochromosomes showed that deca-satellite is occasionally distributed asymmetrically on one or the other of the two pairs of sister chromatids in one diplochromosome. This indicates that major reorganization of the satellite can occur frequently in somatic cells. We discuss several possible mechanisms by which deca-satellite sequences could be either amplified or deleted during a single replicative cycle. Also, on the basis of the marked fluidity of deca-satellite abundance and organization and other well-known attributes of centromeric satellites, we suggest that the existence and maintenance of centromeric satellite rests on the role of the tandem repeats themselves and not on any particular nucleotide sequence, repeat length or organization.

Chromosome Studies in Human Leukemia. I. Acute Leukemia in Children&lt;xref ref-type="fn" rid="FN1"&gt;2&lt;/xref&gt;&lt;xref ref-type="fn" rid="FN2"&gt;3&lt;/xref&gt;

Metaphase chromosome number and morphology were investigated in short-term cultures of leukocytes from the peripheral blood of 7 children with acute leukemia, ranging in age from 3 months to 11 years, and of 2 nonleukemic children, both 6 years old. Leukocytes from the 2 nonleukemic children showed no significant departure from the diploid chromosome number (2n = 46). In 10 karyotype analyses on each of the 2, no detectable structural changes were present in the chromosomes. In all the leukemia cases, the majority of cells also had 46 chromosomes. From 5 to 15 karyotype analyses were made in each case, and the majority of these cells had numerically and morphologically normal chromosome complements. Such structural changes as were present revealed no characteristic pattern. In the 3 cases which had undergone extensive therapy, and in which symptomatic disease had been present for from 6 months to 3 years, the incidence of karyotype change was higher than in the remaining 4 cases, 3 of which were untreated and the fourth of which had been treated for only 5 days. These data are interpreted to indicate that the observed chromosome changes are not causally related to the onset of the disease.