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Reproductive Cycle of a Rockfish, Sebastes schlegeli (조피볼락의 생식주기)

  • BAEK Jae-Min;HAN Chang-Hee;KIM Dae-Jung;PARK Chul-Won;Aida Katsumi
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.5
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    • pp.431-438
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    • 2000
  • To clarify the annual reproductive cycle in a rockfish, Sebastes schlegeli, monthly changes in gonadosomatic index (GSI), hepatosomatic index (HSI) and histological feature of gonads and plasma levels of sex steroid hormones ($estradiol-l7{\beta},\;17{\alpha},\;20{\beta}-dihydroxy-4-pregnen-3-one,\;testosterone\;and\;11-ketotestosterone$) were investigated. The annual reproductive cycle in females could be divided into 5 periods as follows: 1) recovery period (June to September): serum level of $estradiol-l7{\beta}$ increased gradually; 2) vitellogenesis period (Septemer to february) : vitellogenic oocytes were obsewed, GSI sustained high value, and serum level of $estradiol-l7{\beta}$ increased; 3) gestation period (February-April): developing larva showed in the ovary, and serum levels of $17{\alpha},\;20{\beta}-dihydroxy-4-pregnen-3-one$ and testosterone increased; 4) partrition period (April to May) : larva were delivered, and value of GSI and serum levels of hormones decreased rapidly; 5) resting period (May to June) : value of GSI and serum levels of $estradiol-l7{\beta}$ and testosterone remained low. The annual reproductive cycle in males could be divided into 6 periods; 1) early maturation period (April to June): value of GSI and serum levels of hormones incresed gradually, cyst of spermatogonia incresed in number, and a small number of cyst of spermatocyte was observed; 2) mid-maturation perid (June to September); value of GSI and serum levels of hormones increased, and germ cells in many cysts were undergoing active sperrnatogenesis; 3) late maturation period (September to November) : value of GSI and serum levels of hormones remained high and spermatozoa were released into the lumina of the seminal lobules; 3) spermatozoa dischaging period (Nobember to December) : the lumina of the seminal lobules were enlarged and filled with mature spermatozoa; 4) degeneration period (December to Februauy)i value of GSI decresed and cyst of spermatocyte were decresed in number; 5) resting period (December to April) : no histological changes of testes were observed, and value of GSI and serum levels of hormones remained low. In November, the lumina of the seminal lobules were filled with mature spermatozoa and sperm masses were present in the ovarian cavity. Thus, copulation in this species occurred in November and December.

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STUDIES ON THE DIMORPHISM OF THE PERSICARIA SENTICOSA NAKAI (Persicaria senticosa Nakai의 Dimorphism에 관한 연구)

  • HARN, Chang Yawl
    • Journal of Plant Biology
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    • v.3 no.1
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    • pp.16-25
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    • 1960
  • HARN, Chang Yawl (Chonnam U. Kwangju, Korea): Siudies on the dimorpism of the Perisicaria senticosa Nakai-Kor. jour. Bot. 3(1) 16-25 During his researches regarding the morphological and physiological properties of Polygonecenae, the author has found that the species, Persicaria senticosa, aiso, besides the heterostylous plants of Polygonum family, Fagopyrum esculentum, and Persicaria japonica which was recently verified by the author as dimorphic, shows the typical floral structure of heterostylism, the description of which is not found in taxonomical works. Further research on this species have revealed that this plant, despite pressessing characteristic structural dimorphism, does not exhibit even the slight signs of heterostlylous properties physiologically. This is a deviation from the usual behavior of normal heterostylous plants. What is interesting is the fact that the physiological behavior of this species is quite contrary to that of P. japonica which is considered to be the most highly specialized dimorphic plant. Thus it is assurred that if some species of this family had taken a heterostylic form in its course of development from autogamy to allogamy, P. seoticosa would be the least differentiated type of dimorphic forms among the three heterostylous plants, including buckwheat, of this family. The results obtained in this experiment are summarized as follows: 1) P. senticosa has two forms of flower, one, long style-short stamened; the other, short style-long stamened. Not only conspicuous is this primary difference, but the secondary difference, such as pollen grain size, is noticeable between long and short styled individuals, thus expressing structurally the definite trait of a dimorphic plant. 2) Structural alteration of floral parts towards dimorphism has preceeded far less in comparison with those of the P. japonica and F. esculentum. 3) Elaborate studies on fertility reveal that this species does not show the slightest sign of the physiological characteristics of dimorphic plants. In other words, regardless of the modes of combinations, legitimate and illegitimate, fertilization and fruit setting flourish unimpaired. 4) Growth of pollen tubes apparently parallels the results in the fertility, tubes reaching ovary approximately 30 minutes after pollination both in legitimate and illegitimate combinations. Pollen tube penetration appears to be comparatively rapid. 5) A slight difference in the growth of pollen tube seems to exist between legitimate and illegitimate combinations, legitimate union giving slightly faster tube penetration. 6) In the present experiment it was clarified that P. senticosa, known to possess one form of flower in taxonomy, is in reality dimorphic plant having two of flowers. Although this species is definitely heterostylous in floral structure, physiological evidence and pollen tube behavior show that the differentiation of this plant toward the dimorphism has apparently proceeded slightly except for some parts of floral organ. In ordinary heterostylous plants it is a matter of common occurrence that when illegitimately cmbined, there is poor or no fertility, Contrary to the universal property of heterostylous plants, no difference is observed in the fertility and pollen tube growth between the legitimate and illegitimate combinations in the case of P. senticosa. Compared to the P. japonica and F. esculentum, which are supposed to have undergone high degree of dimorphic differentiation, it is an unavoidable conclusion that P. senticosa has not yet developed as a heterostyle plant except for some of its floral parts. If P. japonica is assumed to be the most differentiated type of hetenostylous plant, thenthe P. senticosa would be regarded as the primitive, retaining still the self-fertile nature so common to the Polygonum genus. In nature, however, this plant has a better chance to be pollinated legitimately owing to the two forms of flowers than to be pollinated illegitimately. The author is indebted to Dong Chul, Kim as well as other members of the Department of Plant Breeding and Genetics of Chonnam National University for their efforts out the laborious experiments during the course of the present studies.

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Effects of Boyanghwano-Tang on the Development of Experimentally-induced Endometriosis in the Rats (보양환오탕(補陽還五湯)이 실험적으로 유발된 흰쥐의 자궁내막증에 미치는 영향)

  • Lim, Sung-Min;Lee, Dong-Nyung;Seo, Il-Bock;Kim, Hyung-Jun
    • The Journal of Korean Obstetrics and Gynecology
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    • v.23 no.3
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    • pp.56-77
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    • 2010
  • Purpose: This study was performed to investigate effects of Boyanghwano-Tang on the development of experimentally-induced endometriosis in rats. Methods: Endometriosis was induced in rats by autotransplanting uterine tissue to the peritoneum and divided them into three groups: (1) sham-operated group(n=8), (2) surgically induced endometriosis and untreated control group (n=8), (3) surgically induced endometriosis and Boyanghwano-Tang treated group. Boyanghwano-Tang was orally administrated for 15 days after operation. Then we measured the body weight, the volume of endometriotic implants, the weight of uterus and ovary, and investigated the concentration of cytokines (MCP-1, TNF-$\alpha$, IL-$1{\beta}$, IL-6) in peritoneal fluids. Histopathology, immunohistochemistry for COX-2 and VEGF, and histochemistry for mast cell in transplanted uterine tissue were performed. Results: - The volume($mm^3$) of endometriotic implants in Boyanghwano-Tang treated group ($122.3{\pm}45.0$) was significantly decreased(p<0.05) compared with control group($222.1{\pm}109.1$). - The concentration(pg/$m{\ell}$) of MCP-1 in peritoneal fluids in Boyanghwano-Tang treated group($1026.3{\pm}196.5$) was significantly decreased(p<0.05) compared with control group($1412.5{\pm}345.7$). - The concentration(pg/$m{\ell}$) of TNF-$\alpha$ in peritoneal fluids in Boyanghwano-Tang treated group($936.5{\pm}94.3$) was significantly decreased(p<0.01) compared with control group($1126.2{\pm}139.9$). - The concentration(pg/$m{\ell}$) of IL-$1{\beta}$ in peritoneal fluids in Boyanghwano-Tang treated group($78.5{\pm}13.3$) was significantly decreased(p<0.01) compared with control group($105.3{\pm}17.6$). - The concentration(pg/$m{\ell}$) of IL-6 in peritoneal fluids in Boyanghwano-Tang treated group($107.4{\pm}15.8$) was decreased compared with control group($122.8{\pm}19.3$). - Histopathologically, proliferation of endometriotic epithelia, infiltration of inflammatory cells and angiogenesis in transplanted uterine tissue of Boyanghwano-Tang treated group were weakly observed than those of control group. - The percentage of positive epithelial layers for COX-2 in Boyanghwano-Tang treated group($51.5{\pm}14.1$) was significantly decreased(p<0.01) compared with control group($75.1{\pm}16.3$). - The VEGF expression of endometriotic epithelia, neovascular endothelia and stromal cells in transplanted uterine tissue of Boyanghwano-Tang treated group were weakly observed than those of control group. - The number of mast cells in adjacent tissue of transplanted uterine tissue in Boyanghwano-Tang treated group($75.9{\pm}13.1$) was decreased compared with control group($91.0{\pm}28.3$). Conclusion: On the basis of these results, we concluded that Boyanghwano-Tang have inhibiting effects on the development of transplanted uterine tissue. And these effects may be related with decreased production of MCP-1, TNF-$\alpha$, IL-$1{\beta}$ and decreased expression of COX-2 and VEGF by administration of Boyanghwano-Tang.

Components and Biological Activity of Aqueous Extract Isolated from Winged Stem of Euonymus alatus (화살나무 물 추출물의 구성성분과 생리활성)

  • Oh, Bong-Yun;Hwang, Soo-Kyung;Cheong, Mi-Young;Sin, Hong-Sig;Park, Bock-Hee;Lee, Jeong-Ho;Kim, Soo-Hyun
    • Korean Journal of Food Science and Technology
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    • v.37 no.6
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    • pp.898-904
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    • 2005
  • Although Euonymus alatus (EA) has been used as traditional medicine for cancer treatment, exact substances involved in curing of the disease are not yet known. Free radical scavenging and reactive oxygen species (ROS) removal activities of aqueous extract components isolated from winged stem of EA in animal cell line were investigated. Aqueous extract of EA (AEEA) was fractionated by ultrafiltration. All fractions mainly consisted of polysaccharide (44.8%), protein (2.1%), small amounts of phenol compounds and organic acids. Antioxidant activity of AEEA increased depending on concentration fractions, as determined by 1,1-diphenyl-2-picrylhydrazyl method. ROS removal activity was visualized in Chinese hamster ovary cell line using laser scanning confocal microscope, and AEEA activity increased in order of F IV>F III>F I>F II. These results suggest AETA has bioactive carbohydrates with potentials as functional foods and antioxidants.

Annual Reprodutive Cycle of the Jackknife Clams, Solen strictus and Solen gordonis (맛조개, Solen strictus와 붉은맛, Solen gordonis의 생식년주기)

  • CHUNG Ee-Yung;KIM Hyung-Bae;LEE Taek-Yuil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.19 no.6
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    • pp.563-574
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    • 1986
  • The structure of gonads, gametogenesis and reproductive cycle of the jackknife clams, Solen strictus and Solen gordonis were investigated mainly by histological observation. The first species used were monthly sampled at the coastal area of Dadaepo, Pusan, Korea and Naechodo, Kunsan, Korea for one year from February 1982 to January 1983. The second species were monthly sampled at the sand beach of Dadaepo, Pusan, Korea, from February 1982 to January 1983. Sexualities of Solen strictus and Solen gordonis are dioecious, and these species are oviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary was composed of a number of small ovarian sacs and the testis was composed of several testicular lobuli which from the tubular structure. Early multiplicating oogonium was about $10{\mu}m$ in diamater. Nucleus and nucleolus, at that time, were distinct in appearance. Each of the early growing oocytes made an egg-stalk, connected to the germinal epithelium of the ovarian sac. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed in the ovarian sacs in the early development stages. With the further development of gonad, these tissue and cells gradually disappeared. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells function as nutritive cells in the formation and development of the early stage germ cells. Mature oocytes were free in the lumen of ovarian sacs and gradually become round or oval. Ripe oocyte was about 80 to $90{\mu}m$ in diameter. With the further development of testis, each of the testicular lobuli formed stratified layers composed of spermatogonia, spermatocytes, spermatids and spermatozoa in groups on the germinal epithelium. After spawning, the gonad gradually degenerated, and disorganized completely. Then new differentiated tissues were rearranged next year. The annual reproductive cycle of those species could be classified into five stages; multiplicative, growing, mature, spent, degenerative and resting stage. It seems that the spawning season is closely related to the water temperature, and the spawning of Solen strictus occurs from June to July at above $20^{\circ}C$ in water temperature. The peak spawning season appeared in June at Dadaepo and in July at Kunsan, The spawning of Solen gordonis occurs from May to June with the peak spawning season in June. Percentages of the first maturity in female of Solen strictus ranging from 5.1-6.0 cm and 7.1-8.0 cm in shell length were $50\%$ and $100\%$, respectively.

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The Effects of Human Follicular Fluid on Embryonal Development of Mouse in In Vitro Culture (체외배양에서 인간 난포액이 생쥐의 배 발달에 미치는 영향)

  • Min, Bu-Kie;Choi, Ki-Wook;Kim, Kie-Suk;Lee, Hee-Sub;Hong, Ki-Yeon;Lee, Bong-Ju;Lee, Sun-Young;Park, Seung-Teak
    • Clinical and Experimental Reproductive Medicine
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    • v.26 no.2
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    • pp.171-178
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    • 1999
  • The follicular fluid (FF) of ovary contains various biological active products which affected on the growth of follicles and the fertilization of oocyte in physiological reproductive process of mammals. This study was designed to determine the effects of human FF on fertilization of oocyte and embryonal development in vitro culture. The FF was prepared as clear without blood contamination by needle aspiration from mature follicles of human at the time of oocytes retrieval for in vitro fertilization (IVF). As the medium for culture in vitro of embryonal cells, human tubal fluid (HTF) supplemented with follicular fluids at concentrations of 10%, 40% and pure FF were used. These effects were compared to control group of cultured embryos in HTF supplemented with 0.4% BSA (bovine serum albumin). For IVF, 64 eggs in control group, 67 eggs in 10% FF, 57 eggs in 40% FF and 64 eggs in pure FF were respectively allocated. And the rates of fertilization were almost similar in all groups as resulting 82.81% in control, 85.07% in 10% FF, 87.71% in 40% FF and 81.25% in pure FF. On the examination for embryonal cleavage from fertilized eggs, the rates of developing to 4 cell stage was similar in all groups, as results 98.11% in control, 98.27% in 10% FF and 98% in 40% FF but 78.84% in pure FF. And the rates of developing to 8-16 cell stage were significantly reduced as 44% in 40% FF and 44.23% in pure FF (p<0.05) compare to 71.69% in control media. As likewise, the rates of developing to morular stage were also significantly reduced to 36% (p<0.05) and 21.15% (p<0.01) respectively in 40% FF and pure FF. And the rates to blastocystic stage of embryo was lowest as 7.69% in pure FF (Table 1). The quality of embryonal cells on cleavage to the 8-16 cell stage was poorer, higher concentrations of FF. The rates of grade 1 in pure FF, as 23.07%, was lowest compare to those of other groups, in which the rates of grade 1 in control, 10% FF and 40% FF were 58.49%, 47.36% and 34% respectively. And on the contrary, the rate of grade 4 in pure FF was highest as 23.07%, while those were 5.66% in control, 8.77% in 10% FF and 20% in 40% FF (Table 2). On the viability of embryos, the rate of embryonal cell death was more rise, at the higher concentrations as well as longer exposure in the follicular fluid. At 48 hours after in vitro culture of embryos, the rate of survival embryos in pure FF was markedly lowered as 44.23%, compare to that of control (p<0.05). But there was not significant difference between the rates of survival embryos in each group beside the pure FF, which the rates were 77.35% in control, 70.17% in 10% FF and 60% in 40% FF respectively. And at 72 hours after in vitro culture, the rates of survival embryos were also significantly dropped to 21.15% in pure and 36% in 40% at concentration of FF compare to 62.26% in control (p<0.05, p<0.01). Finally, the rate of embryonal death at 96 hours after in vitro culture was highest as 82.69% in pure FF among all groups which those were 35.84 in control, 56.14% in 10% FF and 64% in 40% FF respectively (Fig. 1, 2, 3). In conclusion, this study suggests that the FF has no effects, in particular, to the in vitro fertilization of oocytes but exerted a bad effect to the cleavage, quality and viability of the embryonal cells during in vitro culture. However, the FF is harmful on embryonal development at conditions in higher concentration and especially on the embryos after $8{\sim}16$ cell stage.

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Sexual Maturation and Feeding Habit of Korean Mandarin Fish, Siniperca scherzeri (Perciformes, Centropomidae) in the Seomjin River and Imjin River, Korea (섬진강과 임진강에 서식하는 쏘가리 Siniperca scherzeri (Perciformes, Centropomidae) 집단의 성 성숙 및 섭식특징)

  • Lee, Wan-Ok;Baek, Jae-Min;Lee, Jong-Ha;Kim, Kyeong-Hwan;Kim, Chi-Hong;Yoon, Seung-Woon
    • Korean Journal of Environment and Ecology
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    • v.26 no.1
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    • pp.57-66
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    • 2012
  • This study was conducted to investigate the reproductive ecology of the Korean Mandarin Fish, Siniperca scherzeri in Seomjin River and Imjin River from April to October 2008. After have investigating the relationship between standard length (SL) and Gonadosomatic index (GSI) of Siniperca scherzeri, we can conclude that the body length of maturation was over 200mm SL in case of females and over 180mm SL in males. The GSI of the females that were from Seomjin river was the highest in April (7.43%), and gradually decreased after May (5.55%) and June (3.58%). The GSI was decreased sharply in August and indicated the lowest value in September (0.44%). The GSI of the females that were from Imjin river showed similar tendency of females' GSI from Seomjin river. The GSI of males from Imjin river was totally higher than that of females, it was 5.96% in April, and 8.03% in May. It was lowered in early June, and late June, it indicated 2.12%. In September, it was the lowest value (0.20%), and increased after October (0.54%). The result of histological study of ovary presented similar result of the study of GSI in Seomjin river and Imjin river. The ratio that fishes constitute in stomach contents of Siniperca scherzeri was 92% in Seomjin river and 90% in Imjin river. Digestion of food organisms and the ratio of unidentifiable fishes in stomach contents was fairly high, and it was 50% in Seomjin river and 72.2% in Imjin river. In the period of study, eating ratio was very low 38.3% (36 ind.) in Seomjin river and 21.8 (53 ind.) in Imjin river.

Effects of GnRH Agonist Used for Ovarian Hyperstimulation in Human IVF-ET on the Apoptosis of Preovulatory Follicular Cells (인간 체외수정 및 배아이식에 있어서 과배란 유도 과정에 사용한 GnRH Agonist가 배란 전 난포내 과립 세포의 세포자연사에 미치는 영향)

  • Yang, Hyun-Won;Kwon, Hyuck-Chan;Hwang, Kyung-Joo;Park, Jong-Min;Oh, Kie-Suk;Yoon, Yong-Dal
    • Clinical and Experimental Reproductive Medicine
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    • v.26 no.1
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    • pp.55-65
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    • 1999
  • There have been many reports to date regarding the role of GnRH as a local regulatory factor of ovarian function as studies of human and rat ovaries revealed GnRH and its receptor. In recent studies it has been shown that GnRH directly causes apoptosis in the granulosa cells of the rat ovary, and such results leads to the suggestion that the use of GnRH agonist for more stable long term ovarian hyperstimulation in human IVF-ET programs causes granulosa cell apoptosis which may lead to follicular atresia. Therefore this study attempts to determine if granulosa-luteal cell apoptosis occurs in patients during IVF-ET programs in which GnRH agonist is employed for ovarian hyperstimulation. The quality of oocyte-cumulus complexes obtained during ovum pickup procedures were assessed morphologically and then the fertilization rate and developmental rate was determined. Apoptotic cells among the granulosa-luteal cells obtained during the same procedure were observed after staining with Hematoxylin-eosin. The fragmentation degree of DNA extracted from granulosa-luteal cells was determined and comparatively analyzed. There was no difference in the average age of the patients, the number of oocytes retrieved, and fertilization and developmental rates between the FSH/hMG group and GnRH-long group. There was also no difference in the apoptosis rate and pyknosis rate in the granulosa-luteal cells between the two groups. However, when the oocyte-cumulus complexes were morphoogically divided into the healthy group and atretic group without regard for the method of hyperstimulation, the results showed that the number of oocytes obtained averaged $11.09{\pm}8.75\;and\;10.33{\pm}4.53$ per cycle, respectively, showing no significant difference, but the fertilization rate (77.05%, 56.99%, respectively, p<0.01) and developmental rate (65.96%, 41.51%, respectively, p<0.01) was significantly increased in the healthy group when compared to the atretic group. The degree of apoptosis in the granulosa-luteal cells showed that in the healthy group it was 2.25% which was not significantly different from the atretic group (2.77%), but the pyknosis rate in the atretic group (27.81%) was significantly higher compared to the healthy group (11.35%, p<0.01). The quantity of DNA fragmentation in the FSH/hMG group was 32.22%, while in the GnRH-long group it was 34.27%, showing no significant difference. On the other hand the degree of DNA fragmentation was 39.05% and 11.83% in the healthy group and atretic group, respectively, showing significantly higher increase in the atretic group (p<0.01). The above results suggest that death of granulosa-luteal cells according to the state of the oocyte-cumulus complex is more related to pyknosis rather than apoptosis. Also, the GnRH agonist used in ovarian hyperstimulation does not seem to directly affect the apoptosis of retrieved oocytes and granulosa-luteal cells, and which is thought to be due to the suppression of the apoptogenic effect of GnRH agonist as a result of the high doses of FSH administered.

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The Studies on the Bionomics of the Florida Wax Scale, Ceroplastes floridensis Comstock(Coccidae) on Persimmon Tree (감나무에 기생하는 Ceroplastes floridensis Comstock(Coccidae)의 생태에 관하여)

  • Han Kyo Pil;Lee Eui Soon
    • Korean journal of applied entomology
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    • v.3
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    • pp.31-39
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    • 1964
  • The authors studied on the bionomics of the Florida wax scale, Ceroplastes floridensis Comstock and bionomics of two kind of parasites which attack on this Florida wax scale in 1963 to 1964. 1. Ceroplastes floridensis Comstock was heavily infested on the persimmon tree planted in the southern part of Korea, specially at the center of Taegu city. Parasitic ratio of important parasite of Ceroplastes floridensis Comstock, Microterys clauseni was $66.67\%$ and appeared low parasited ratio at the center of the city. 2. The developed eggs of the Ceroplastes floridensis Comstock was appear며 from mid-May to early July. The peak of it was late-May to early June. Average stored eggs inside of a body is 2030. $2030.77\pm0.49.$. 3. The hatching period of the Ceroplastes floridensis Comstock begins from early June to early July. Mid-June was the peak period of it. Pupation period of the male was August 14 to September 7 and adult was emerged on August 20 to September 8. Mean longevity for adult male was 3 days in August but 4 days in September. 4. On the differences of the body- length parasited on the three host plants, persimmon, platanus, and trifoliate orange, the body length parasited on the persimmon was the largest, medium on platanus and the smallest on the trifoliate orange. 5. Microterys clauseni H. Compere parasite on tile Ceroplastes floridensis Comstock with 5 generations in a year. Hibernate in the body of the host as tan·at stage. The first adult appears in middle April. Fifteen days was required for one generation in $21^{\circ}$. The authors observed on the form ovary, female with 6 ovarioles, and mean number of eggs per female was $47.19\pm0.55$. 6. On the parasited individuals of the Microterys clauseni H. Compere a larva was the most numerous and was found 2 individuals or 4 individuals parasite on the one Ceroplastes floridensis Comstock. 7. Coccophagus app. parasited on the only male body of the Ceroplastes floridensis Comstock. The parasitic ratio was $14.831\%$ on persimmon tree in Taegu city.

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Reproductive Cycle of the Echiuroid Worm Urechis unicinctus(von Drasche) in Southern Korea (한국산 개불, Urechis unicinctus (von Drasche)의 생식주기)

  • 최상덕;김호진;이원교;곽은주;윤호섭;라성주;이인곤
    • Journal of Aquaculture
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    • v.13 no.2
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    • pp.169-174
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    • 2000
  • Reproductive cycle of U. unicinctus was studied from September 1998 to August 1999, using gonadosomatic index (CSI) as an indicator. In November, the CSI values were maximum for male (6.2) and female (7.0), respectively; the values were lowest for them (1.0 and 0.5) during the successive february. Subsequently, they rapidly increased and attained peak by March-April. The values decreased again in both sexes and remained unchanged until August. The index increased in October to attain the peak by November. The CSI values clearly indicated that there are two spawning events in a year, namely the first one during April-May and the second one in December. Reproductive cycle was classified into the following successive stages: in female, multipication (January~February, June ~Setember), maturation (March~April, November), spent (May and December), degeneration and resting (June and January), and in male, multiplication January ~ february, June ~September), maturation (March~April, October~November), spent (May and December) and degeneration and resting (January and June). Histological observations revealed that oocytes in the ovary matured simultaneously in November and March. At the same time, the envelopes of matured testis became thinner than those in the early stage.

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