• Korean Journal of Plant Taxonomy
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• v.39 no.1
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• pp.12-23
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• 2009

To verify hybridity of Asplenium castaneo-viride, external morphology, spore morphology, anatomy and chromosomes of the species and of the two presumed parental species, A. incisum and A. ruprechtii, were examined. A. castaneo-viride usually had 1-pinnately divided frond. However, some individuals had almost simple fronds with pinnatisect basal parts similar to A. ruprechtii, while others had fronds similar to A. incisum in having oblanceolate blades and basal pinnae with triangular, 2-3 lobed apices. On the surface of the spores, sculpturing consisted of folds that were usually prominent; forming long wings, and irregular or incomplete reticulation. However, reticulation patterns varied among species. A. castaneo-viride showed a wide range of variation from sparse to dense patterns, whereas A. incisum showed only from sparse to intermediate patterns. A. ruprechtii showed from intermediate to dense patterns. The spore size of A. castaneo-viride was $54.63{\mu}m$, larger than other two species ($47.81{\mu}m$ in A. incisum and $44.22{\mu}m$ in A. ruprechtii). The level of undulation of epidermal cell wall was also different. A. incisum had the most shallowly undulated wall, and A. castaneo-viride had a pattern intermediate between the two presumed parental species. This same patterns was recognized in the density of stomata. The density of $45.91/mm^2$ in A. castaneo-viride was intermediate between the two presumed parental species ($67.00/mm^2$ in A. incisum, and $37.86/mm^2$ in A. ruprechtii). Chromosome number was constant (2x =2n = 72) as in A. incisum and A. ruprechtii. However, A. castaneo-viride showed a different ploidy level. The populations of Mt. Mai (Jeonbuk province) and Mt. Duryun (Jeonnam province) were diploid (2n = 72) which is a new record for this taxon, whereas the population of Mt. Buram (Seoul) was tetraploid (2n = 144). Conclusively, A. castaneo-viride was revealed to be a hybrid of A. ruprechtii and A. incisum based on evidence involving leaves, spores, epidermal cells, stomata and chromosome number.

• Journal of Korean Society of Forest Science
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• v.51 no.1
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• pp.1-21
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• 1981

Populus glandulosa and Populus tomentiglandulosa, which were known to be natural hybrids, were examined for morphological, physiological and karyological traits to illucidate its hybridity and taxonomical importance. The results abtained were as follows; 1. Survival rate in rooting of cuttings and grafting was different between the hybrids and their rooting abilities showed incomplete dominance. 2. Their leaf openings showed incomplete dominance. The leaf longevities of P. alba ${\times}$ glandulosa and P. tomentiglandulosa were stronger than the other hybrids. 3. There were differences in resistance to toxicity of $KClO_3$ between the hybrids. 4. Many external leaf characters of the hybrids also showed incomplete dominance. P. tomentiglandulosa was similar in those characters to P. alba ${\times}$ glandulosa while P. glandulosa was similar to hybrids crossed, reciprocally crossed or back-crossed between P. davidiana and P. alba. 5. Their numbers of male flower showed incomplete dominance or hybrid vigor. The numbers of P. tomentiglandulosa were similar to thosa of P. alba ${\times}$ glandulosa while those of P. glandulosa to those of P. alba ${\times}$ davidiana or P. davidiana ${\times}$ alba. 6. Morphology and band color of male catkin bract showed incomplete dominance. Those of P. glandulosa were similar to those of P. alba ${\times}$ davidiana while those of P. tomentiglandulosa to those of. P. alba ${\times}$ glandulosa. 7. There were differences in vascular bundle number and arrangement of petiole between the hybrids. 8. Differences in the anatomical traits of stem did not exist between the hybrids but those in wood fiber size existed. 9. The chromosomes of artificial hybrids, P. glandulosa and P. tomentiglandulosa showed irregular behavior in metaphase I and II. 10. All hybrids including P. glandulosa and P. tomentiglandulosa showed small number of P.M.C. with 19 II but many univalent chromosomes were exhibited in metaphase I. 11. All hybrids including P. glandulosa and P. tomentiglandulosa showed a little abnormal nuclear plates as laggard chromosome and chromosome bridge in anaphase I and II. 12. The frequency of pollen tetrad and fertile pollen was low in most of the hybrids including P. glandulosa and P. tomentiglandulosa.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.386-392
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• 2018

Turner syndrome (TS) is a chromosomal disorder caused by monosomy of the X chromosome, with complete or partial absence of the second sex chromosome. Anomalies of root morphology have been found to occur more often in patients with TS, which make endodontic treatment challenging and requires special handling. The patients with TS may also have systematic problems such as cardiac or renal malformations, so in treating these patients it is important for clinicians not only to be aware of the characteristic intraoral findings, but also to make the patients have regular dental check-ups to prevent oral complications in advance. An 12-year-old girl who had been diagnosed with TS at the age of 10 years was referred due to discomfort in the bilateral mandibular premolar regions. Dens evaginatus and taurodontism were detected in all the mandibular premolars characteristically. The bilateral mandibular first premolars had three roots and the bilateral mandibular second premolars had periapical lesion with two roots. Due to the complexity of the root canal anatomy, root canal treatment were completed with a dental microscope to ensure adequate visualization. After 2 years of regular follow-up examinations, there were no clinical sign or symptom associated with the teeth, and no periapical lesion, was found. This case report describes the characteristic oral features and dental management of TS patients.

• Parasites, Hosts and Diseases
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• v.26 no.2
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• pp.107-111
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• 1988

As a series of systematic classification of paramphistomes, the worms in the rumen and reticulum of 310 Korean cattle slaughtered at Chonju abattoir were collected from February 1986 to June 1987 and were classified by morphology of the worms. Afterwards, the karyotype of Fischoederius cobboldi (Poirier, 1883), which is a very rare species in Korean cattle, was studied with germ cells of the worm by means of modified air-drying method. The chromosome numbers in the haploid and diploid cells of 315 F. cobboldi were n=9 and 2n=18, respectively. The meiotic divisions were observed frequently; 1,904 haploid and 49 diploid cells were recognized. Nine pairs of mitotic chromosomes were homologous in the metaphase stage and the chromosomes were composed of seven medium-sized metacentrics (m) or submetacentrics (sm) and two small-sized submetacentrics (sm). While, meiotic metaphases were composed of seven medium and two small·sized chromosomes. The 3rd, 4th, 2nd and 5th pairs of chromosomes was metacentric having centromere indices of 40.4%, 40.0%, 39.7% and 38.9%, respectively, and the remaining ones were submetacentric with centromere indices from 32,4% to 36.2%. As a series of C-banding method, C-band was shown in centromeric region from all of the haploid germ cells, except chromosome No. 1 which included heterochromatin at the tip region. Chromosomes No, 4, 6 and 9 showed remarkable C-band distinguished from others.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.284-290
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• 2010

This study was carried out to breed a self-compatible variety of Tiger Lily from the seedlings originated from Chinju city, Gyeongsangnam-do. The morphological characteristics, ploidy, and the resistance of seedlings to virus infection were investigated. A progeny test was also conducted to examine whether the propagated progenies had the same characteristics as the mother plant. The self-compatible diploid lily variety developed in this study showed a tall type like native triploid lily, Lilium tigrinum, and bulbils were formed on both lily varieties. The morphological characteristics of the flowers and leaves were not much different between the varieties, while the size of the bulbils and bulbs showed significant differences. The percentage of seed generation by self-pollination was 72.6% for the self-compatible variety, while there was no seed generated for native triploid lily. The number of chromosome was 2n = 26 (x = 13, diploid) for the self-compatible variety, while 2n = 39 (x = 13, triploid) in native lily variety. The progenies of the self-compatible diploid lily variety showed the same characteristics as those of its mother plant in morphology, seed germination, and polyploidy. The mother plant of the self-compatible diploid lily variety showed 58% pollen germination and the 2-year-old and 3-year-old progenies showed similar germination percentages. The pollen grains of Korean native triploid lily, however, never germinated.

• Korean Journal of Animal Reproduction
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• v.26 no.1
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• pp.33-39
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• 2002

This study was conducted to investigate the effect of $Ca^{2+}$ concentration in fusion medium on the fusion, nuclear morphology and the development of bovine somatic cell nuclear transfer embryos. Bovine skin cells were transferred into an enucleated oocyte and fused with cytoplasm in the fusion medium containing with 0.05 to 1.0 mM Cacl$_2$. Nuclear transfer embryos were activated with a combination of A23187 and cycloheximide. Nuclear transfer embryos were fixed at 3 h after fusion or cultured for 7 ~8 days. Fusion rate was significantly (P＜0.01) increased by increasing the $Ca^{2+}$ concentrations in the fusion medium from 0.05 mM (56.6%) to 0.5 mM (50.1%) and 1.0 mM (84.3%). More than 80% of reconstituted embryos underwent premature chromosome condensation (PCC) with 0.05, 0.1 mM CaCl$_2$, whereas 54.5% and 59.3% of embryos formed pronucleus (PN) directly without PCC in the 0.5 and 1.0 mM CaCl$_2$, groups. Blastocyst formation rates were significantly (P＜0.05) different between 0.1 mM and 1.0 mM CaCl$_2$groups. From the present result, it is suggested that the elevated $Ca^{2+}$ concentrations in fusion medium can enhance the fusion and blastocyst formation rates of bovine nuclear transfer embryos.bryos.

• Molecules and Cells
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• v.19 no.3
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• pp.436-444
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• 2005

We describe the morphology and molecular organization of heterochromatin domains in the interphase nuclei, and mitotic and meiotic chromosomes, of Brassica rapa, using DAPI staining and fluorescence in situ hybridization (FISH) of rDNA and pericentromere tandem repeats. We have developed a simple method to distinguish the centromeric regions of mitotic metaphase chromosomes by prolonged irradiation with UV light at the DAPI excitation wavelength. Application of this bleached DAPI band (BDB) karyotyping method to the 45S and 5S rDNAs and 176 bp centromere satellite repeats distinguished the 10 B. rapa chromosomes. We further characterized the centromeric repeat sequences in BAC end sequences. These fell into two classes, CentBr1 and CentBr2, occupying the centromeres of eight and two chromosomes, respectively. The centromere satellites encompassed about 30% of the total chromosomes, particularly in the core centromere blocks of all the chromosomes. Interestingly, centromere length was inversely correlated with chromosome length. The morphology and molecular organization of heterochromatin domains in interphase nuclei, and in mitotic and meiotic chromosomes, were further characterized by DAPI staining and FISH of rDNA and CentBr. The DAPI fluorescence of interphase nuclei revealed ten to twenty conspicuous chromocenters, each composed of the heterochromatin of up to four chromosomes and/or nucleolar organizing regions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.328-328
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• 2017

Drought is a major limiting factor that reduces rice production and occurs often especially under recent climate change. Plants have the ability to alter their developmental morphology in response to changing environment, which is known as phenotypic plasticity. In our previous studies, we found that one chromosome segment substitution line (CSSL50 derived from Nipponbare and Kasalath crosses) showed no differences in shoot and root growth as compared with the recurrent genotype, Nipponbare under non-stress condition but showed greater growth responses compared with Nipponbare under mild drought stress condition. We hypothesized that reducing root respiration as metabolic cost, which may be largely a consequence of aerenchyma formation would be one of the key mechanisms for root plasticity expression. This study aimed to evaluate the root respiration and aerenchyma formation under various soil moisture conditions among genotypes with different root plasticity. CSSL50 together with Nipponbare and Kasalath were grown under waterlogged conditions (Control) and mild drought stress conditions (20% of soil moisture content) in a plastic pot ($11cm{\times}14cm$, ${\varphi}{\times}H$) and PVC tube ($3cm{\times}30cm$, ${\varphi}{\times}H$). Root respiration rate was measured with infrared gas analyzer (IRGA, GMP343, Vaisala, Finland) with a closed static chamber system. There was no significant difference between genotypes in control for shoot and root growth as well as root respiration rate. In contrast, all the genotypes increased their root respiration rates in response to mild drought stress. However, CSSL50 showed lower root respiration rate than Nipponbare, which was associated by higher root aerenchyma formation that was estimated based on internal gas space (porosity) under mild drought stress conditions. Furthermore, there were significant negative correlations between root length and root respiration rate. These results imply that reducing the metabolic cost (= root respiration rate) is a key mechanism for root plasticity expression, which CSSL50 showed under mild drought.

• BMB Reports
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• v.41 no.9
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• pp.651-656
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• 2008

A mouse with cataract, Kec, was generated from N-ethyl-N-nitrosourea (ENU) mutagenesis. Cataract in the Kec mouse was observable at about 5 weeks after birth and this gradually progressed to become completely opaque by 12 weeks. Dissection microscopy revealed that vacuoles with a radial or irregular shape were located primarily in the cortex of the posterior and equatorial regions of the lens. At the late stage, the lens structure was distorted, but not ruptured. This cataract phenotype was inherited in an autosomal recessive manner. We performed a genetic linkage analysis using 133 mutant and 67 normal mice produced by mating Kec mutant (BALB/c) and F1 (C57BL/6 $\times$ Kec) mice. The Kec locus was mapped to the 3 cM region encompassed by D14Mit34 and D14Mit69. In addition we excluded coding sequences of 9 genes including Rcbtb2, P2ry5, Itm2b, Med4, Nudt15, Esd, Lcp1, Slc25a30, and 2810032E02Rik as the candidate gene that causes cataract in the Kec mouse.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.257-262
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• 2008

Genetic diversity of cultivated wheat is narrowing down and is increasingly becoming non-complacent in tackling new pathogenic races and adverse environmental situations. Wild relatives of wheat are rich repositories of beneficial genes that are capable of defying adverse situations. However, these wild species are not readily crossable with cultivated ones. The present study attempted to cross three wild wheat species as females with three cultivated species of varying ploidy to understand the intricate behaviour of hybrids in relation to cytology, morphology, and molecular recombination. Post-fertilization barriers caused hybrid recovery in wild species in contrast to cultivated species. Triticum monococcum did not produce hybrids in any of the crosses. Various degrees of chromosome anomalies and hybrid sterility were seen with hybrids of T. timopheevi and T. sphaerococcum. Cytoplasmic factors were suspected to add more to the abnormality. G genome from T. timopheevi could enhance more pairing between Band D of cultivated species. Precocity of certain chromosomes in laggard formation was evident, pointing towards evolutionary self balance of the genomes which prevented homeologous pairing. They are eliminated in hybrids. Molecular diversity clearly corroborated with genetic proximity of the species, which distinguished themselves by maintaining the genome homeology.