• Plant Resources
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• v.1 no.2
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• pp.109-112
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• 1998

Aloe in vitro culture was attempted to induce callus and regeneration ability from different explant sources onto MS medium with 0.5mg/l NAA plus 1.0mg/l BA. Anthers that no developed any callus and plant regeneration, while only four out of 274 filament explants induced calli at cut edge without regenerated plants. Twenty ovary explants regenerated four direct plantlets without via callus from the base of epidermal tissues. Regenerated plants on the root tip gave 2n=14 of chromosome numbers.

• Journal of Korean Biological Nursing Science
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• v.8 no.1
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• pp.5-14
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• 2006

Staphyloccus aureus is one of the most important pathogens in clinical settings. It is also one of the leading causes of nosocomial infections and the dissemination of multiple drug-resistant strains, mainly methicillin resistant Staphyloccus aureus, and the recent emergence of a vancomycin resistant MRSA is the concern to hospital worldwide. MRSA strains have acquired multiple resistance to a wide range of antibiotics, including aminoglycosides and macrolides. $\beta$-Lactam resistance of methicillin-resistnat Staphyococcus aureus is determined by the function of penicillin binding protein 2'(PBP2') encoded by the methicillin resistance gene mec A. MRSA strains carry methicillin resistance gene mecA, encoded by a mobile genetic element designated staphylococoal cassette chromosome mec(SCCmec). MRSA clones are defined by the type of SCCmec element and the genotype of the methicilline-susceptible Staphyococcus aureus chromosome in which the SCCmec element is integrated.

• Journal of Korean Neurosurgical Society
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• v.39 no.2
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• pp.136-140
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• 2006

The authors report three microcystic meningiomas with its characteristic immunohistochemical findings and chromosomal pattern. Three patients with surgically treated microcystic meningioma were studied for its radiological, histopathological findings, and chromosomal analysis was done in the one patient. Tumors were convexity meningioma in the frontal area. The tumors were enhanced homogenously in the two, and enhanced in homogenously with multiple small cysts in the other one on preoperative magenetic resonance image. Pathological examination showed marked nuclear pleomorphism, many small cysts, hyaline thickening in blood vessel wall, and mucinous background, compatable to microcystic type. EMA and vimentin were positive on the immunohistochemical stain. Chromosomal analysis showed tetrasomies of chromosome 5, 13, 17, and 20, and trisomies of chromosome 6, 7, 9, 11, 12, 16, 19, and 21, which are quite different from those of benign meningioma.

• Journal of Food Hygiene and Safety
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• v.9 no.2
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• pp.67-74
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• 1994

This study was aimed to find out the comparative effects between non-irradiated, and 5kGy-10kGy of gamma-irradiated Panax Ginseng Radix powder on the genotoxicity for identification of possibility of DNA damage causing cancer. Four different short-term mutagenicity tests were used: (1) Salmonella typhimurium reversion assay (Ames test) (2) Chromosome aberration test in cultured Chinese hamster lung (CHL) fibroblast cells. (3) Micronucleus test in ddY mouse (4) Somatic mutation and recombination test in the wing cells of Drosophila melanogaster.Gamma-irradiated Panax Ginseng Radix powder revealed negative results in these four mutagenicity tests. This means gamma-irradiated ginseng could be safe on the genotoxic point of view.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.36-41
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• 1986

These experiments were carried out to obtain basic information necessary for sexing embryos by chromosomal analysis. To observe metaphase chromosomes, all embryos developed to blastocysts were cultured in Ho, pp. & Pitts' medium containing 0.001% Colcemid under the gas phase of 5% CO2 in air at 37$^{\circ}C$ for 2 hours. The sex chromosome of mouse embryos shown normal development after culture in medium containing H-Y antiserum (10%, v/v) and complement (20%, v/v) also was confimed by chromosomal analysis. The results obtained in these experiments were summarized as follows: 1. Among 89 mouse blastocysts, the number of embryos identified to have XX and XY chromosome was 22(25%) and 25(28%), respectively and 42(47%) embryos were not identified. 2. Of total 40 mouse balstocysts cultured in medium containing H-Y antiserum and complement, 23(58%) embryos which were able to be discriminated their sex chromosomes were identified to be XX bearing embryos. 3. Sex chromosomes of a number of embryos subjected to chromosomal analysis were not identified. This result may be due to absence or poor quality of metaphase spreads.

• Journal of Plant Biology
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• v.38 no.4
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• pp.321-328
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• 1995

Calli obtained from basal disc explants of Allium victorialis var.platyphyllum wre grown in three kinds of nutrient media (MS, BDS, and B5), and the frequencies of mitotic index and the chromosomal aberrations were analysed. The mitotic index varied from 0.55% to 1.01% with respect to culture media and ages. The mitotic irregularities like micro-, bi- and multi-nuclei, chromosome bridge and laggards were noted in each types of calli. The chromosome number variations observed in metaphase stage were identified aneuploid and tetraploid. Structural variations such as dicentric chromosomes, centromere breakage and small chromosomes were observed. Relationship between basal medium and chromosomal variability was not observed in this study. But, in BDS medium, NAA and BA had a more effect on number variation than kinetin.

• Animal cells and systems
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• v.10 no.2
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• pp.65-71
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• 2006

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is one of the most common inherited renal disorders in the world. Mutations in PKD1 located on chromosome 16p13.3 are responsible for 85% of all the ADPKD patients whereas mutations in PKD2 on chromosome 4q21-23 are responsible for the rest of the cases. Genetic heterogeneity and the problems of mutation detection in PKD1 suggest that linkage analysis is an important approach to study the genetics of ADPKD. To evaluate the availability of six (CA)n microsatellite markers for the linkage analysis of ADPKD in the Korean population, we examined the allele frequencies and heterozygosities of the markers. With the exception of KG8, five markers were highly informative, with PIC values over 0.5, but the PIC value of KG8 marker was less informative than other five markers because of the low number of alleles. Therefore, this study will be useful in linkage analysis for ADPKD families in the Korean population.

• Journal of Plant Biology
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• v.11 no.1
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• pp.33-37
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• 1968

Present investigation was carried out in order to make clear the fertility, morphological characters, and chromosome numbers of interspecific hybrids of Chrysanthemum Zauadskii, C. indicum, and C. lavandulaefolium. 1. Hybrids were not self-pollinated. When sib-crossed the fertility was 1.3~19.3%. 2. F2 individuals were variable in their morphological Characters. 3. Chromosome numbers of three putative parents were different from those reported previously: C. zawadskii 2n=36, C. indicum 2n=20, C. lavandulaefolium 2n=16, $C. indicum{\times}C. zawadskii 2n=28, C. zawadskii{\times}C. indicum-1 2n=28, C. zawadskii{\times}C. indicum-2 2n=28, C. zawadskii{\times}C. indicum-3 2n=28, C. zawadskii{\times}C. indicum-4 2n=28, C. zawadskii{\times}C. indicum-5 2n=28, C. zawadskii {\times}C. lavandulaefolium-1 2n=26, C. zawadskii{\times}C. lavandulaefolium-2 2n=26.$

• The Korean Journal of Zoology
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• v.16 no.3
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• pp.171-176
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• 1973

Metaphases were obtained from the bone marrow cells of B. kangii Yoon, by means of direct air-drying technique. The karylogical characteristics of this species were as follows; 1) The diploid chromosome number was 22(2n=22) which might be divided into six large and five small homololgous chromosmes. 2) All homologous chromosomes of this species were metacentrics. 3) The secondary constriction was not found in all members of chromosomes. 4) There was no evidence for the existence of a specific sex chromosome pair in this species.

• Molecules and Cells
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• v.45 no.5
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• pp.273-283
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• 2022

During meiosis, homologous chromosomes (homologs) pair and undergo genetic recombination via assembly and disassembly of the synaptonemal complex. Meiotic recombination is initiated by excess formation of DNA double-strand breaks (DSBs), among which a subset are repaired by reciprocal genetic exchange, called crossovers (COs). COs generate genetic variations across generations, profoundly affecting genetic diversity and breeding. At least one CO between homologs is essential for the first meiotic chromosome segregation, but generally only one and fewer than three inter-homolog COs occur in plants. CO frequency and distribution are biased along chromosomes, suppressed in centromeres, and controlled by pro-CO, anti-CO, and epigenetic factors. Accurate and high-throughput detection of COs is important for our understanding of CO formation and chromosome behavior. Here, we review advanced approaches that enable precise measurement of the location, frequency, and genomic landscapes of COs in plants, with a focus on Arabidopsis thaliana.