• The Korean Journal of Zoology
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• v.6 no.2
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• pp.21-27
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• 1963

This study is concerned with alterations in chromosomes (numbers and morphology) when the culture of Chinese hamster cells (FAF-28 strain) was treated by steroids, testosterone and DOC. 1. In 200 cells of normal untreated cells as control population the chromosome of stemline was decided as which was contained in 158 cells ; that is , in 79 percent of the population. The average chromosome number in above 20 cells observed was calculated as 23.95 with minimum limit at 20 and maximum limit at 70. 2. Many different chromosome numbers, ranging from 19 to 352 were observed in the 200 cells treated by testosterone. The diploid number of 22 showed the peak of variation curve was counted in 71 cells (35.5%) and an average chromosome number of stemline was 22 which was counted in 74 cells (37%). While all of the chromosome number of stemline was 22 which was counted in 74 cells (37%). While all of the chromosome numbers in the 200 cells observed ranged from 20 to 181 , an average chromosome number was also found to be 30.09. 4. The chromosome component in the cultured normal FAF-28 cells with 22 diploid chromosomeswas as follows ; 9a) 2 paris were long and metacentric (LM), (b) 3 pairs were medium length and metacentric (MM), (c) 3 pairs were small and subtelocentric (SS) and (d) 3 pairs were small and metacentric (SM). 5. The twenty cells with 44 chromosomes were selected at random from each cell population treated with testosterone and DOC , so that chromosome idiogram and morphology could be studies. In the twenty cells of the testosterone treated population the average ratio of above four groups, LM ; MM;Ss:SM, was found to be 8.6 : 10.8:13.5:10.7. On the other hand, the average ratio in the same number of cells of the DOC treated one was 7.7 :11.4:12.5:12.7. 6. The five types of the altered chromosomes morphologically in the hundred cells selected at random from each cell population treated by testosterone and DOC were observed (Type I-V). The thirty-one altered chromosomes were found to be in the testosterone treated cell population and the sixteen in DOC treated.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.317-331
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• 1990

Chromosomes of gonadal tissues from Fasciola spp, Eurytrema pancreaticum and Calicophoron calicophorum occurred Korean cattle were egamined using modified air-drying method. To compare their phenotype with three different genotypes among Fasciola spp, the adult and egg si2e were measured since they have been known as important taxonomical characters. The results obtained were as followed; Cattle liver fluke, Fasciola spp were classified into three types based on their chromosomal complements such as individual with 2o chromosome(diploid), 30 chromosome(triploid) and 20/30 mosaic constitution(mixoploid). The propotions of appearance of three types were 40.00%, 54.29% and 5.71%, respectively. The frequency of three types in type I which was regarded as F gigantica were 58.82% for diploid, 35.29% for triploid and 5.88% for mixoploid, but in type II which was regarded as F hepatica were 72.2% for triploid, 22.22% for diploid and 5.56% for mixoploid. Egg length of triploid forms was significantly larger than that of diploid forms and egg size of mixoploid forms was similiar to that of triploid forms. Worm size of triploid forms was larger than that of diploid forms and was more similar to that of mixoploid forms, but the statistical data were not significant. Diploid chromosome consisted of one pair of metacentric chromosome(m), four pairs of submetacentric chromosomes(sm), five pairs of subtelocentric chromosomes(st), while triploid chromosome consisted of one pair of metacentric chromosome, seven pairs of submetacen.tric chromosomes, one pair of subtelocentric chromosome and telocentric chromosome(t), respectively. In mixoploid chromosome, constitution of the chromosomes of diploid or triploid cell was consistent with that of diploid or triploid. Chromosomes of gonadal tissues from pancreatic fluke, Eurytrema pancreaticum consisted of 13 pairs of homologs(2n=26, n=13). The mitotic and meiotic divisions were observed frequently. In the mitotic metaphase, Karyotype consisted of five pairs of metacentric chromosomes, four pairs of submetacentric chromosomes, three pairs of subtelocentric chromosomes and one pair of telocentric chromosome. Chromosomes of gonadal tissues from stomach fluke, Calicvphoron calicophorum consisted of 9 pairs of homologs(2n=18, n=9). The meiotic divisions was frequently observed, but mitotic divisions was rare. In the mitotic metaphase, Karyotype consisted of two pairs of metacentric chromosomes, three pairs of submetacentric chromosomes and four pairs of subtelocentric chromosomes. Karyotype of Calicophoron calicophorum differed from that of Japanese C calicophorum which was similar to that of Paramphistomum cervi of Korean cattle. Though that of Calicophoron calicophorum of Korean cattle was similar to that of Paramphistomum explanatum of Korean cattle, that have been recognized to be a different species of fluke.

• The Korean Journal of Malacology
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• v.23 no.1
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• pp.39-49
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• 2007

We investigated to understand the differences in the karyotypes and the reproductive characteristics between the diploid clam, Corbicula japonica in the brackish water and the triploid clam, C. fluminea in the freshwater. The number of chromosomes of the diploid C. japonica were 38, which can be grouped into 19 pairs of two homologues. These can be divided into 11 pairs of telocentric, 4 pairs of subtelocentric, 3 pairs of submetacentric and one pair of metacentric chromosomes. C. japonica is oviparous and dioecious. The clam has two pairs of gills, with the inner and outer-demibranchs, however, they do not act mainly as marsupia. External fertilization occurs in the brackish water. The triploid marsh clam, C. fluminea has 54 chromosomes, which can be grouped into 18 sets of three homologues. These 18 sets can be divided into one metacentric group, five submetacentric groups and 12 subtelo- or telocentric groups. C. fluminea is ovoviviparous and functional hermaphrodite. The triploid condition may be closely related to hermaphroditism. This species has the inner-demibranchs acting mainly as marsupia. The depletion of ripe eggs occurred in the inner-demibranchs of the gill during the incubatory periods, and ripe eggs produced in the hermaphroditic follicles in the gonad during the non-incubatory periods. The gonad developmental stages of two marsh clams (C. japonica and C. fluminea) can be divided into five stages: early active stage, late active stage, ripe stage, partially spawned stages, and spent/inactive stage.

• The Korean Journal of Malacology
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• v.12 no.1
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• pp.33-38
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• 1996

강원도 동해안에서 채집된 백합과 1종, 대복의 염색체수와 핵형을 분석하였다. 대복의 염색체수는 2n=38이며, 핵형의 구성은 3쌍의 metacentric과 16쌍의 submetacentric염색체로 구성되었다.

• Journal of Ship and Ocean Technology
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• v.11 no.3
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• pp.1-13
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• 2007

A semi-submersible drilling rig is regarded as one of the typical offshore structures operated in the field with moderate environments such as the Gulf of Mexico, Brazil, and West Africa. Its typical roll and pitch natural periods are around 30 seconds, which avoids prevailing regions of the wave energy spectrum, and their responses in waves are quite acceptable for common operation conditions. But large roll and pitch motions can be induced by wave difference frequency energy spectrum if the metacentric heights of a semi-submersible decrease to small values in some loading conditions, and it is because the roll and pitch natural periods increase and approach to the region where the spectral density of the low frequency wave drift moment has significant value. This paper describes the low frequency roll motion of a semi-submersible that are excited by the wave 2nd order difference frequency energy by a series of model experiments. From the model tests with several different initial metacentric heights (GM), it was observed that a semi-submersible can experience large roll motion due to the wave group spectrum.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.1
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• pp.30-38
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• 1996

Meiotic metaphase chromosomes of the testis of two storage insects, tobacco moth (Ephestia elutella H.) and cigarette beetle (Lasioderma serricorne F.) were examined to study their karyotypes. The number of haploid chromosomes of the tobacco moth was 31 and the karyotype was characterized by 29 metacentric and 2 submetacentric chromosomes. The metaphase chromosome length of tobacco moth ranged ca. 1.44-2.11${\mu}{\textrm}{m}$ and the average length was 1, 78${\mu}{\textrm}{m}$. The number of haploid chromosomes of the cigarette beetle at metaphase was 10 and the karyotype was characterized by 8 metacentric and 2 submetacentric chromosomes. The range of metaphase chromosome length of the cigarette beetle was ca. 1.79- 2.39${\mu}{\textrm}{m}$ and the average length 2.09${\mu}{\textrm}{m}$.

• Journal of Life Science
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• v.11 no.4
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• pp.354-361
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• 2001

Chromosomal characteristics of New Zealane White rabbit was studied at meiosis and mitosis. The meiotic chromosomal preparations were mad with the modified air-drying method and karyotype analysis was performed with the G-banding technique, using isolated mitotic metapase chromosomes of the New Zealand White rabbit. Chromosomes, sex vesicles and centromeres could be classified in the zygotene and the pachytene of the meiosis I. The hair-like processes projecting laterally from the axes of bivalent chromosomes at the mid-to-late pachytene were observed and made the appearance of the lampbrush chromosome structure. Chromosomes could be classified onthe basis of the numbers and locations of chiasma in the diakinesis. Twenty-one autosomal bivalents and a single unequal terminally associated X-Y bivalent were observe during the late prophase and the metaphase of the meiosis I. Most of the bivalent types observed in the New Zealand White rabbit spermatrocytes were 1CH, 1TAl, and 2TA bivalents. The mean chiasma frequency(CF) of the male New Zealand White rabbit was 30.2 and it was found that the CF value tended to decrease through diakinesis and the metaphase I. The karyotype of the New Zealand White rabbit was a male chromosome number of 44(2n=44) comprising 8 pairs of metacentric, 9 pairs of submetacentric, 4 pairs o acrocentric autosomes, metacentric X chromosome and acrocentric Y chromosome.

• Journal of Navigation and Port Research
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• v.27 no.5
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• pp.451-458
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• 2003

A ship with small metacentric height or high speed vessel performs relatively large roll angles in her manoeuvring motion. Roll coupling effect should be taken into consideration for accurate prediction of manoeuvring motion of such a ship. This paper proposes a new mathematical model of ship manoeuvring motion taking coupling effect of roll into consideration. Some kinds of manoeuvring motion are simulated by computer, based upon the proposed model. The simualted results by proposed model here are compared with those by existing model. The proposed model is found to be practical and useful for prediction of manoeuvring motion with roll effect.

• Korean Journal of Ichthyology
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• v.2 no.2
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• pp.211-216
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• 1990

Mitotic analyses of the coho salmon (Oncorhynchus kitsuch) revealed a mode of 2n=60 whit 46 meta or submetacentric and 14 acrocentric chromosomes (NF=106). Individuals with 2n=61 were also found in both sexes in the same population; the karyotype is composed of 45 meta or submetacentric and 16 acrocentric chromosomes (NF=106). This result may indicate that Robertsonian chromosomal polymorphism occurred in the population of the coho salmon.

• Parasites, Hosts and Diseases
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• v.36 no.4
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• pp.277-279
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• 1998

A karyotype analysis of the chromosome of Neodiplostomum seoulense, one of causative agents of human intestinal trematodiasis, was done from the gonad tissue by the squashing method. The chromosome number was n=10 and 2n=20. Chromosome length was $1.30-4.0{\;}\mu\textrm{m}$. Chromosome pairs in the complement consisted of two pairs of metacentric, five pairs of submetacentri$cs_telocentric and three pairs of telocentric chromosomes. These data were comparable with those of other intestinal trematodes.es.