• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.127-135
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• 1999

Cryopreservation is able to store the surplus pre-embryos for freezing and furthermore thawing and transfer in a subsequent cycle. Cryopreserving cells which are maintaining their viability are the very complex process. This study has been carried out in order to find the effects of cryopreservation steps, freezing media and embryonic stages on the rates of viability and development of cryopreserved mouse embryos. Female ICR mice ($6{\sim}8$ weeks old) were induced to superovulate by sequential intraperitoneal injection of 5 IU PMSG and 5 IU hCG 48h apart. Mouse embryos were collected according to its developmental stage after the injection of hCG. Embryos were cryopreserved not only by cryoprotectant step (1 step${\sim}$4 step) but also in a variety of media (HTF, IVF medium, D-PBS) and cell stage. The results were as follows: There is no clear advantage in these freezing media of rapid method, but 4 cell and 8 cell of slow method (2, 3, 4 step) have advantage in D-PBS. The development of embryos according to cell stage become greater in 8 cell stage. In the treatment steps of cryopreservation, the development of embryo to blastocyst was similar among rapid method, but the development of 4 cell and 8 cell embryos to blastocyst according to slow method was better than rapid method.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.41-51
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• 2003

Reproductive cycle with the gonadal development of Ruditapes philippinarum can be classified into five successive stages by histological observations: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (May to October), and spent/inactive stage (August to February). Changes in total protein contents in the adductor muscle tissues reached the maximum in the early and late active stages (February) and appeared the minimum in the ripe and partially spawned stages (May), while changes in their contents in the visceral mass tissues reached the maximum in the ripe and partially spawned stages (June) and gradually decreased in the partially spawned stage (June to October). On the whole, changes in total protein contents showed a negative correlationship between the adductor muscle and visceral mass tissues (r = -0.292, p < 0.05). Changes in total lipid contents in the adductor muscle tissues reached the maximum in the inactive and early active stages (January) and sharply decreased in the early and late active stages (February), while their contents in the visceral mass tissues reached the maximum in the ripe and partially spawned stages (April) and gradually decreased in the partially spawned stage (to October). On the whole, changes in total lipid contents showed a negative correlationship between the adductor muscle and visceral mass tissues (r = -0.699, p<0.05). Changes in glycogen contents in the adductor muscle tissues reached the maximum in the late active and ripe stages (April) and rapidly decreased in the partially spawned stage (May to October), while their contents in the visceral mass tissues reached the maximum in the early and late active stages (February) and rapidly decreased in the late active stage (March). Thereafter, their levels gradually increased in the ripe and partially spawned stages (April to July). On the whole, changes in glycogen contents appeared no correlationship between the adductor muscle and visceral mass tissues (r = 0.062, p > 0.05). These results indicate that the adductor muscle and visceral mass tissues are an important energy storage and nutrient supply organ in the Manila clams, and the nutrient contents of the adductor muscle and visceral muscle tissues change in response to gonadal energy needs.

• The Korean Journal of Malacology
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• v.21 no.2 s.34
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• pp.121-132
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• 2005

We investigated the reproductive cycle with gonad developmental phases of Sinonovacula constricta by histological observations, and seasonal changes in biochemical component of the adductor muscle, visceral mass, foot muscle and mantle were studied by biochemical analysis, from January to December, 2004. The reproductive cycle of this species can be classifed into five successive stages: early active stage (March to May), late active stage (May to July), ripe stage (July to September), partially spawned stage (August to October) and spentfinactive stage (October to March). Total protein content was the highest in the following order: adductor muscle, visceral mass, foot muscle, and mantle. Except for mantle, it was generally higher during the ripe and spawning stages, while lower during the spent/inactive stage. There were positive correlations in total protein contents among adductor muscle, foot muscle, and visceral mass. However, the correlations were not statistically significant. Total lipid content was the highest in the visceral mass; it was more than 5 or 6-fold higher than those in the adductor muscle, foot muscle, or mantle. The monthly change was also most dynamic in the visceral mass. It first Increased during the early active stage (March to May), decreased during late active stage (May to July), and then increased again rapidly during the spawning stage (September). There were a strong negative correlation in total lipid contents between foot muscle and adductor muscle (r = -0.634, p = 0.027), and a strong positive correlation between adductor muscle and mantle (r = 0.665, p = 0.018). Glycogen contents showed more or less similar pattern to total lipid contents in the adductor muscle, foot muscle, and visceral mass. It was higher during the early active and spawning stages, while lower during the late active and spent/inactive stages. There was no statistically significant correlation in glycogen contents among different tissues. Especially, total lipid content showed a negative correlationship between the foot muscle, adductor muscle, visceral mass and mantle. Therefore, these results indicate that the nutrient content of the foot muscle, adductor muscle, viseral mass and mantle changed in response to gonadal energy needs.

• Mycobiology
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• v.37 no.3
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• pp.171-182
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• 2009

Many aspergilli that belongs to ascomycetes have sexuality. In a homothallic or self-fertile fungus, a number of fruiting bodies or cleistothecia are formed in a thallus grown from a single haploid conidia or ascospores. Genome-sequencing project revealed that two mating genes (MAT) encoding the regulatory proteins that are necessary for controlling partner recognition in heterothallic fungi were conserved in most aspergilli. The MAT gene products in some self-fertile species were not required for recognition of mating partner at pheromone-signaling stage but required at later stages of sexual development. Various environmental factors such as nutritional status, culture conditions and several stresses, influence the decision or progression of sexual reproduction. A large number of genes are expected to be involved in sexual development of Emericella nidulans (anamorph: Aspergillus nidulans), a genetic and biological model organism in aspergilli. The sexual development process can be grouped into several development stages, including the decision of sexual reproductive cycle, mating process, growth of fruiting body, karyogamy followed by meiosis, and sporulation process. Complicated regulatory networks, such as signal transduction pathways and gene expression controls, may work in each stage and stage-to-stage linkages. In this review, the components joining in the regulatory pathways of sexual development, although they constitute only a small part of the whole regulatory networks, are briefly mentioned. Some of them control sexual development positively and some do negatively. Regarding the difficulties for studying sexual differentiation compare to asexual one, recent progresses in molecular genetics of E. nidulans enlarge the boundaries of understanding sexual development in the non-fertile species as well as in fertile fungi.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.449-458
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• 2013

This study investigated purplish Washington clam, Saxidomus purpuratus on its gonadal development, reproductive cycle and shell length (age) at 50% female group maturity from January to December 2011 in Jinhae Bay, Korea. This species is dioecious. The gonad index (GI) began to increase in January, reached the maximum value in May and to decrease in June, reached the minimum value in September then to increase slowly in October again. The reproductive cycle of the clams can be divided into five successive stages: the early active stage (Ea, from February to March), the late active stage (La, from January to March and October to December), the ripe stage (R, from January to May), the spawning stage (S, from June to December) and the degenerative and inactive stage (Ia, from January to February and November to December). The spawning periods were from June to December and the main spawning periods were from July to October. The shell length at 50% female group maturity (SL50) was estimated to be 63.6 mm, which can be converted as sexual maturity age of 2.2 year.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.45-55
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• 2001

Gametogenes, reproductive cycle, first sexual maturity(biological minimum size), sex ratio and larval development of the marsh clam Corbicula japonica were investigated monthly by histological observations. Samples were collected in brackish water of Gokgang stream, Kyungsangbuk-Do, Korea, from August 1997 to July 1998. Sexuality of Corbicula japonica is dioecious and the species are an oviparous clam. The gonads are irregularly arranged from the sub-region of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of ovarian sac which are branched arborescent. Oogonia actively proliferate along the germinal epithelium of ovarian sac, in which young oocytes are growing. The testis is composed of a number of testicular tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between developing oocytes and spermatocytes in the early developmental stages. With the further development of the ovary and testis these tissue and cells gradually disappear. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells are considered to be related to the growing of the oocytes and spermatocytes. The spawning period is from July to September, and the main spawning occur between July and August when seawater temperatures reach above 22$^{\circ}C$. The reproductive cycle of this species can be divided into five successive stages; early active (February to April), late active (May to July), ripe (June to September), partially spawned (July to September), degenerative (September to October) and resting stage (October to February). Percentages of first sexual maturity of female and male clams ranging in length from 10 mm to 12 mm are over 50% and 100% for clams over 16.0 mm in shell length. Fertilized eggs or Corbicula japonica were 80-90 ${\mu}{\textrm}{m}$ in diameter. In the early embryonic development of C. japonica, the appearance of polar body, trochophore and D-shaped veliger were observed around 40 min., 27 hours and 4 days after spawning, respectively, at a water temperature of 26.5-28.$0^{\circ}C$. The size of larvae of early umbo stage was about 185-210 ${\mu}{\textrm}{m}$ in shell length, 160-180 ${\mu}{\textrm}{m}$ in shell height around 7 days after fertilization. The correlation of relative growth between the culture day (D) and shell length (SL) was expressed by the following simple formula from D-shaped veliger to metamorphosing stage; SL = 13.300D + 209.36($r^2$= 0.9078).

• The Korean Journal of Malacology
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• v.25 no.1
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• pp.29-33
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• 2009

This study devised and tested a histological staging system for gonadal development in the trumpet shell, Charonia sauliae, which was collected along the south coast of Jeju Island, South Korea. This paper details for the first time the gonadal development characteristics of C. sauliae. Ovary and testis development in C. sauliae can be roughly divided into five stages: growing, mature, spent, degenerative, and resting. The trumpet shelll has multiple fecundation and fertilization during the spawning season for out-of-step gonadal development in high-temperature and low-salinity environments. Female trumpet shell tended to have larger shells and were more abundant than males (64.26% of all animals collected were female).

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.211-220
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• 1995

Though the endometriosis is not always related with infertility, endometriosis causes infertility in some patients. There are many treatment modalities of infertile patients who have endometriosis. In recent years, Assisted Reproductive Technology(ART) have been widely accepted as being a useful tool for the treatment of infertile endometriotic patients. The objective of this study was to evaluate the outcome of ART in infertile endometriotic patients who have been carried out IVF-ET from Jan, 1992 to Dec, 1994 and to compare the results between COH/IUI and IVF-ET in the patients with endometriosis stage I. Tubal disease only patients were grouped(308 patient, 956 cycles) as a control. Endometriosis group was subdivided into 4 groups according to American Fertility Society classification; endometriosis stage I (45 patients, 61 cycles), stage II (26 patients, 39 cycles), stage III (26 pateitns, 37 cycles), stage IV (33 patients, 50 cycles). The outcomes of IVF-ET in endometriosis patients were as follows; The oocyte recovery rates were significantly lower in stage III, IV endometriosis. In case of stage III endometriosis, the fertilization rate was significantly lower than other stages of endometriosis. Clinical pregnancy rates per cycle were not different between the tubal group(22%) and the endometriosis group(25%). According to endometriosis stage, the implantation rate and clinical pregnancy rate were significantly lower in stage IV (5.6%, 16%) compared with other stages (I; 10.0%, 26%, II;9.8%, 31%, III;12.6%, 32%). It suggests that some factor like autoantibodies may inhibit implantation of embryos in stage IV endometriosis. To evaluate the possibility that simply increasing the number of gametes at the site of fertilization might account for pregnancies attributed to IVF-ET, the authors retrospectively analyzed the outcome of couples undergoing IUI during hMG cycles and CC cycles between 1992 and 1994 in the women with endometriosis stage 1. In case of stage I endometriosis, though the COH/IUI group showed lower FSH level and lesser age profile than IVF-ET group, IUI group has resulted in lower pregnancy rates(19.2%) compared with the IVF-ET group(26.2%). In conclusion, endometriotic infertile patients can get comparable pregnancy rates with the tubal factor infertility patients during IVF-ET program. Moreover even in stage I endometriosis, IVF-ET may be an more effective treatment modality than COH/IUI.

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.13-18
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• 2007

This study was carried out to investigate the effects of ovarian estrus stage of oocytes and supplementation of medium with BSA, cysteine and myoinositol on in vitro maturation of canine oocytes. The in vitro maturation(IVM) rate to metaphase II (M II) stage of oocytes recovered from different stage of the reproductive cycle (inactive, follicular and luteal stage) cultured in TCM-199 media were $0.0{\pm}0.0%$, $10.0{\pm}4.1%$ and $5.7{\pm}1.6%$, respectively. The IVM rate of oocytes collected from follicular stage was significantly higher in inactive or luteal stage of oocytes. The IVM rates of oocytes recovered from different stage of the reproductive cycle cultured in TCM-199 media with 5% BSA and 0.1 mM cysteine were$0.0{\pm}0.0%$, $15.8{\pm}4.7%$, $5.6{\pm}1.5%$, respectively. The IVM rates of oocytes recovered from different stage of the reproductive cycle cultured in TCM-199 media with 5% BSA and 10 mM myoinositol were $0.0{\pm}0.0%$, $18.4{\pm}4.6%$ and $5.7{\pm}1.9%$, respectively. The IVM rate of follicular stage oocytes was significantly higher in oocytes collected from follicular stage and with cultured 5% BSA and 0.1 mM cysteine or 5% BSA and 10 mM myoinositol compared to other experimental group.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.75-84
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• 2004

Reproductive cycle, the condition index, sex ratio of the Pacific oysters, Crassostrea gigas were investigated by histological and morphometric data. The specimens were collected in the two oyster farms of Geoje and Namhae, Gyeongsangnam-do, Korea, from November 1995 to October 1996. Growth of shell length in two regions was similar, but growth of total weight of the oyster in Namhae was faster than that in Geoje oyster farm. The spawning periods in female and male clams were from July to October in Geoje and from June to October in Namhae oyster farm. Ripe oocytes were approximately 50 m in diameter. The reproductive cycle of in females and males in Geoje and Namhae oyster farms can be divided into five successive stages: early developing, late developing, ripe, partially spawned and spent/inactive. Monthly changes in gonad developmental phases showed somewhat different patterns between female and male clams except for the spawning period. On the whole, however, monthly changes in the gonad developmental phases showed a similar pattern in the same sex. The sex ratios of females to males in Geoje and Namhae oyster farms were not significantly different from a 1:1 sex ratio ($x^2$ = 0.55 (p > 0.05) in Geoje and $x^2$ = 0.27 ( p > 0.05) in Namhae). Artificial induction of maturation by heating of adult oysters (two-year-old) was investigated from 17 January to 18 March in 1996. Maturity at the fixed water temperature group of $20^{\circ}C$ was 80%, it showed the highest maturity of experimental groups cultured for five weeks. The survival (%) of Crassostrea gigas in the raised water temperature experimental groups (15, 20, $25^{\circ}C$) were over 98.5%, as similar to the control group (100%). But, the survival of C. gigas in the fixed water temperature experimental groups (15, 20, 25, $30^{\circ}C$) were decreased with the increase of the water temperatures. In the fixed water temperature experimental group of $30^{\circ}C$, the survival was 51.1%. Base on these results, the fixed water temperature of $20^{\circ}C$ was the best condition for artificial induction of sexual maturation.