• Journal of Microbiology and Biotechnology
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• v.18 no.9
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• pp.1510-1517
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• 2008

Expresssed sequence tag (EST) analysis was developed from three cDNA libraries constructed from cells of the digestive tract, gonad, and liver of sea squirt. Randomly selected cDNA clones were partially sequenced to generate a total of 922 ESTs, in which 687 unique ESTs were identified respectively. Results of BLASTX search showed that 612 ESTs (89%) have homology to genes of known function whereas 75 ESTs (11%) were unidentified or novel. Based on the major function of their encoded proteins, the identified clones were classified into ten broad categories. We also identified several kinds of immune-related genes as identifying novel genes. Sequence analysis of ESTs revealed the presence of microsatellite-containing genes that may be valuable for further gene mapping studies. The accumulation of a large number of identified cDNA clones is invaluable for the study of sea squirt genetics and developmental biology. Further studies using cDNA microarrays are needed to identify the differentially expressed transcripts after disease infection.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.352-357
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• 2003

Gonadal development and gametogenic cycle of the equilateral venus, Gomphina collected in the coastal waters of Gangneung, Gangwon-do, Korea were investigated by means of histological method from March 2001 to February 2002. Sex of the clam was dioecious. The gonads are composed of a number of gametogenic follicles. The gonad index (GI) was reached the maximum in June (3.87), and the minimum in August (0.66). The condition index (CI) was reached the maximum in May (0.051), and the minimum in January (0.028). The gametogenic cycle of the clam could be divided into five stages inactive (September to November), early active (November to March), late active (April to May), ripe (June and July) and spent/degenerative stage (July to August). Sex ratio (male/female) was 1:0.9.

• Journal of radiological science and technology
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• v.34 no.3
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• pp.189-193
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• 2011

Sitting position upper extremity X-ray examinations (SUEX) is the most widely used patient positioning method for upper extremity X-ray examinations. For this method, the radiation dose is considerable for relatively less interesting organs. We investigated whether patients need to wear the apron during the examination or not. We also studied the examination methods which can reduce the radiation dose. The results showed that radiation dose was reduced as the distance of source to patient becomes longer and the thickness of object grows higher.

• Development and Reproduction
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• v.14 no.1
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• pp.1-5
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• 2010

We investigated the androgenic effects of 11-ketotestosterone (11-KT) on gonadal sex reversal and spermatogenesis in honeycomb grouper Epinephelus merra by method of gonadal biopsy. 11-KT was injected intramuscularly at a concentration of 1 and $10{\mu}g$ body weight. The proportion of cross sectional area of the gonad occupied by each germ cell type was measured and compared pre- and post-injection group. During the sex change phase, the distribution ratio of oocytes was decreased in all fish of 11-KT treatment group while the distribution ratio of spermatocytes was increased than pre-injection group. In male phase, all fish of 11-KT treatment group shown the increased distribution ratio of spermatocytes, but the distribution ratio of spermatozoa was decreased than pre-injection group. The present results suggest that 11-KT can stimulate degeneration of oocytes, proliferation of spermatocytes and spermiation in honeycomb grouper.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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• pp.287-291
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• 2009

This study examined the maturation and main spawning season of Japanese spear lobsters, Linuparus tirgonus(Von Siebold) captured around Jeju island from January to September, 2008. Carapace length(CL), body weight(BW) and gonad weight(GW) were measured. Gonadosomatic index(GSI) and sex ratio were calculated. In female group, CL showed the highest value in June and decreased after August. GW showed a peak in July and decreased rapidly after August. The mean gonadosomatic Index(GSI) reached a maximum value between June and August. Number of egg ranged from 143,360 to 189,504.

• Journal of Aquaculture
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• v.8 no.3
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• pp.231-240
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• 1995

This study was conducted to examine early gonadogenesis by using a histological method for the appearance of primordial germ cells (PGCs), protrude of genital ridge, and formation of primitive gonads in diploid and triploid mud loach, Misgurnus mizolepis. The pattern of early gonadogenesis including appearance of PGCs, formation of genital ridge, and development of primitive gonad in both diploid and triploid were not different histologically. Characteristics of PGCs of triploid were also the same as those of diploid. However, gonadal length of diploid was significantly longer than that of triploid (P<0.05).

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.512-512
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• 2004

Venus clam, Protothaca jedoensis was collected in lune 2003 from Yosu, Korea. The prevalence and infection intensity of Perkinsus was determined by Ray's Fluid thioglycollate medium technique and Choi's 2 M NaOH digestive assay. The prevalence of infection was 80% in Yosu; 54.2% in Taejon and 15.5% in Sachon. Consequently, infection intensity was highest in clams from Yosu (6250${\pm}$8188 Perkinsus cells/g of tissue) whereas lower levels were found in Taejon (5072${\pm}$10862 Perkinsus cells/g of tissue) and in Sachon (2452${\pm}$15300 Perhnsus cells/g of tissue). Histological observation showed that Perkinsus presented in mantle, gills, digestive tubes and gonad of clams. The hemocytic infiltrations and tissue damages were found in heavy Perkinsus-infected clams. Results after immunofluorescence staining with antibody developed from Perkinsus atlanticus suggested that there is closed relationship between Perkinsus found in Venus clam and Manila clam.

• Journal of Aquaculture
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• v.17 no.2
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• pp.128-132
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• 2004

Reproductive cycle of the brown sole, Limanda herzensteini was investigated by means of histological methods. The testis showed the presence of seminiferous tubule. The tubule consisted of many testicular cysts, each of which contained numerous germ cells - all at the same developmental stage. The ovary consisted of several ovarian lamellae and the oogonia originated from the inner surface of the ovarian lamella. Oocyte development was group-synchronous. Gonadosomatic index (GSI) of the male and female was the highest in January and March, respectively. Reproductive cycle could be classified into the growing (June-September), maturation (October-December), ripe and spent (January-March), and recovery and resting (April-May).

• 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.

• Journal of Aquaculture
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• v.9 no.1
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• pp.19-23
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• 1996

Hormonal induction of sex reversal was examined by using sex steroid hormones in serranid fish, Epinephelus septemfasciatus. Young fish were collected from the coastal area of Cheju Island, and reared for 2 years before fish were used for the experiments. Without any hormonal treatment, gonads of fish ($1,000\~2,800$ g in body weight) were occupied by oocytes of the perinucleolus stage and bundles of protogonial cells in the area of germinal epithelium. When the induction of sex reversal was attempted by daily oral administration of $17\alpha$-methyltestosterone (0.5 mg/kg fish) for 90 days, active spermatogenesis was induced, and spermatogonia and spermatocytes and spermatids were appeared in all gonads we examined. However, after daily, oral treatment of $17\beta$-estradiol (0.5 mg/kg fish) to. 50 days with the following injection of human chorionic gonadotrophin ($1,000\~1,500$ IU/kg fish) mature oocytes were not induced in fish gonad.