• Journal of Plant Biology
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• v.30 no.4
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• pp.225-247
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• 1987

Meiosis and postmeiotic mitosis in Boletus rubinellus were examined ultrastructurally. Meriosis occurred at the apex of the basidium. A sausage-shaped spindle pole body(SPB) was observed along with the presence of synaptonemal complexes during pachytene and a diglobular SPB was present on late pachytene or diplotene nuclei. During metaphase I, the monoglobular SPB at the spindle pole was surrounded bya membrane and the nuclear enveloope was discontinuous. At anaphase I, the chromosomes became better defined and formed a central spindle. The nucleolus was extruded from the nucleus. During anaphase I, the SPB was excluded from the chromosomal region by a membrane and both poles were fully separated to opposite sides of the basidial wall. In meiosis II, the two nuclei divided synchronously and the spindles were parallel. The spindles were smaller than in meiosis I, while the SPB was approximately the same size as that of the similar stage in meiosis I. During anaphasetelophase II, the SPB was surrounded by a cap of endoplasmic reticulum (ER) that delimited it from the spindle. The postmeiotic interphase nuclei migrated to the mid-region of the basidium before migration to the spores. The SPB at this stage was diglobular. A postmeiotic mitosis occurred within the basidiospore, and the plane of the spindle was obique to the long axis of the spore. The spindle and SPB were smaller than at meiosis I and there were fewer nonchromosomal microtubules. At anaphase, the nucleolus was present inside the nuclear envelope but lateral to the spindle.

• Korean Journal of Medicinal Crop Science
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• v.18 no.3
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• pp.186-190
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• 2010

The chromosome number was identified and fluorescence in situ hybridization(FISH) mapping of 5S and 45S rDNAs were conducted for C. minima and C. lanceolata in the genus Codonopsis from Jeju island. In this study, we have confirmed that the somatic metaphase chromosome number determined as 2n=2x=16 was the same as the findings from the previous studies. While the conventional staining method makes it rather difficult to distinguish satellite chromosomes due to high degree of variability, FISH analysis produced the exact number and location of 5S and 45S rDNAs. Both species in the genus Codonopsis have a pair of 5S rDNA and their gene loci were observed on chromosome 3. Although two pairs of 45S rDNAs (one on chromosome 1 and the other on chromosome 8) were identified in both species, the 45S rDNA signals on chromosome 8 in C. minima were significantly weaker than those on chromosome 1. In addition, the 45S rDNA signals on chromosome 1 in C. lanceolata showed that the chromosome is non-homologus. In this study, we have determined cytogenetic characteristics of C. minima and C. lanceolata according to their gene replication patterns.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.399-405
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• 2020

The objective of this study was to identify the effect of zebularine soaking on the early growth stage of barley (Hordeum vulgare L.). Hence, root elongation was measured daily according to the different concentrations of zebularine (1.0, 2.5, 5.0, and 10.0 μM) for 4 days. On the first day, root length at 2.5 and 5.0 μM was significantly longer than that in the non-treated control. On the second day, root length was not significantly different among all concentrations and controls. On the third day, root elongation was suppressed by the effect of zebularine, except at 2.5 μM. The treatment time of zebularine accounted for the largest proportion of the variation in root elongation. After transplanting, plant growth velocity was similar to that of the control; however, plants at 2.5 μM showed faster growth velocity than that of the other concentrations and the control. In the metaphase of mitosis, most chromosomes of cells under zebularine treatment were ordinary regardless of the concentration, while some cells with short chromosomes were investigated at around 2%. The short chromosome showed a centromere. In addition, it showed short and long arms based on the centromere. The lengths of the short and long arms were different for each short chromosome. It is necessary to study the effect of the short chromosome as a chromosomal function on plant growth and phenotype through investigation of meiosis and fertilization at the chromosome level.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.1-7
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• 1997

Radiation protection by post-irradiation injection of the ginseng extract in mice was studied. Male ICR mice, 7 weeks old, were orally injected with ginseng extrat(100mg/kg) for 10 days, and with physiologocal saline as the control. Immediately after final injection, mice were whole body irradiated with 5.08Gy(Cs-137 ${\gamma}$-ray, central dose rate : 654Gy/h) which induced Bone marrow death. At 24h after irradiation, micronucleus test and metaphase analysis in bone-marrow were carried, blood cell were counted and the survival rate were carried for 30 days after the irradiation. Stimulated recovery by the extract was observed in thrombocyte count, but that phenomenom was not showed in the erythrocyte and leucocyte counts. The 30-day survival ratio was 5% and 65% for the control and experimental group. Frequencies of micronuclei per 1000 polychromatic erythrocytes were 79.5${\pm}$1.5 in experimental group, 185.9${\pm}$35.8 in control. And Abnormal chromosomes per 50 metaphases were 112 in experimental group and 143 in control.

• The Korean Journal of Zoology
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• v.30 no.1
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• pp.89-98
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• 1987

The research of fused oocytes was conducted to investigate the in vitro mejotic maturation of immature oocytes (GV oocytes) fused with oocytes in germinal vesicle breakdown (GVBD oocytes) in the presence of dbcAMP which is known as one of the strong inhibitors to GVBD. The immature oocytes fused together as well as those fused with GVBD oocytes proceeded to GVBD in 3 hr culture in plain medium. But in the medium containing dbcAMP (100$\mu$g/ml), the immature oocytes fused together did not show any GVBD and thus the fusion itself could not affect the inhibitory activity of dbcAMP. However, all of the immature oocytes fused with GVBD oocytes underwent GVBD in 3 hr culture despite of the presence of dbcAMP. When the culture was extended to 20 hr, nearly all of the immature oocytes fused together were still arrested at the GV stage in the presence of dbcAMP. But most of the fused oocytes which had shown GVBD during 3 hr culture developed to metaphase II stage extruding one or two polar bodies regardless of the presence of dbcAMP. In this experiment, it was found that two sets of the metaphase chromosomes were somewhat concomitant with a pair of the polar bodies in the fused egg. Upon the results of the present studies, it is assumed that there may be a maturation promoting factor(s) in the cytoplasm of the GVBD occytes, and this factor(s) possibly nullifies the function of dbcAMP.

• Korean Journal of Plant Resources
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• v.35 no.5
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• pp.659-666
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• 2022

The effect of rye B chromosome (rye B) on chromosome association was investigated in meiosis of wheat addition line. The wheat addition line was with one Leymus mollis chromosome and one L. racemosus chromosome which are under homoeologous relationship. Chromosome behavior of the two Leymus chromosomes in wheat genetic background was revealed by genomic in situ hybridization. In the first metaphase, most of the two Leymus chromosomes showed univalent in the wheat addition line without rye B (98.1 ± 0.5%). On the other hand, the wheat addition line with rye B showed higher frequency of bivalent (10.3 ± 0.2%) than wheat addition line without rye B (1.9 ± 0.5%). The wheat addition line without rye B showed abnormal bivalents with abnormal structure while the wheat addition line with rye B showed normal bivalent in low frequency. By rye B, some bivalent was composed of wheat and L. racemosus, and some trivalent was composed of wheat bivalents with L. mollis chromosome. Also, some wheat bivalents showed hyper-crossover, so those wheat bivalents showed abnormal structure compared to other wheat bivalents with normal structure such as ring, rod, and pan.

• Journal of Korean Society of Forest Science
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• v.14 no.1
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• pp.39-44
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• 1972

Cytological investigation was done on a tetraploid tree of Robinia pseudoacacia L. selected in the planted forest in Chilbo Mountain. From the results of observation of chromosomes on mitotic metaphase in leaves, it was confirmed that the mutant is tetraploid plant (2n=40). The external form of leaves of the spontaneous tetraploid was gigantic and dark green one in comparison with diploid. There was no difference in the size of guard cell and the number of stomata per unit area between the mutant and the diploid plant, however, length and thickness of wood fiber were increased as compared with that of diploid. The spontaneous gigas tetraploid showed growth performance as much as the colchicine induced gigas tetraploid.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1574-1579
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• 2006

This study was performed to determine the developmental potentials of nuclear transfer (NT) embryos using life-span extended cells transfected with a foreign gene as donor cells. A life-span extended bovine embryonic fibroblast cell line was transfected with an expression vector in which the human type II collagen (BOMAR) and ear fibroblasts were used as a donor cell. Cytogenetic analysis was performed to analyze the chromosomal abnormality of donor cells. The fusion rate of 1.8 kV/cm for $15{\mu}sec$ given twice was significantly higher than that of other groups (p<0.05) and the embryos lysed were significantly higher after 1.8 kV/cm for $20{\mu}sec$ given once compared to other groups (p<0.01). The blastocyst development in the ear cell group was statistically significant compared to both BOMAR groups (p<0.01). Both BOMAR groups cultured more than 40 passages (>40 passages) had a lower number of chromosomes; however, fresh granulosa cell (GC) and BOMAR groups cultured less than 20 passages had normal chromosome numbers. Both >40 passages BOMAR groups had numerous obscure debris in metaphase spreads. The transfected foreign gene was expressed in all BOMAR groups, but not in the GC group. Based on these results, the lower developmental potential of NT embryos using life-span extended donor cells transfected with a foreign gene might be a cause of chromosomal abnormality in donor cells.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.869-876
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• 2015

Wild relative species of domesticated crops are useful genetic resources for improving agronomic traits. Cytogenetic investigations based on chromosome composition provide insight into basic genetic and genomic characteristics of a species that can be exploited in a breeding program. Here, we used FISH analysis to characterize the ploidy level, chromosome constitution, and genomic distribution o f 5S and 4 5S r ibosomal DNA (rDNA) in four wild Cucurbitaceae species, namely, Citrullus lanatus (Thunb.) Mansf. var. citroides L. H. Bailey (2n = 22), Melothria japonica Maxim. (2n = 22), Sicyos angulatus L. (2n = 24), and Trichosanthes kirilowii Maxim. (2n = 66, 88, 110 cytotypes), collected in different areas of Korea. All species were diploids, except for T. kirilowii, which included hexa-, octa-, and decaploid cytotypes (2n = 6x = 66, 8x = 88, and 10x = 110). All species have small metaphase chromosomes in the range of $2-5{\mu}m$. The 45S rDNA signals were localized distally compared to the 5S rDNA. C. lanatus var. citroides and M. japonica showed one and two loci of 45S and 5S rDNA, respectively, with co-localization of rDNA signals in one M. japonica chromosome. S. angulatus showed two co-localized signals of 5S and 45S rDNA loci. The hexaploid T. kirilowii cytotype showed five signals each for 45S and 5S rDNA, with three being co-localized. This is the first report of hexaploid and decaploid cytotypes in T. kirilowii. These results will be useful in future Cucurbitaceae breeding programs.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.402-407
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• 2003

Karyotype analysis and chromosomal localization of 5S and 45S rDNAs using multi-color fluorescence in situ hybridization (McFISH) technique were carried out in Bupleurum longeradiatum. Somatic metaphase chromosome number was 2n=12. Karyotype was composed of three pairs of metacentrics (No.3, 4 and 6) and three pairs of submetacentrics (No. 1, 2 and 5). The length of somatic prometaphase chromosomes ranges from 2.55 to $5.05{\mu}m$ with total length of $18.15\;{\mu}m$. In FISH experiment, one pair of 5S rDNA signals was detected on the pericentromeric region of chromosome 4 and one pair of 45S rDNA signals was detected on the telomeric region of chromosome 2.