• Korean journal of applied entomology
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• v.48 no.3
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• pp.301-310
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• 2009

For the comparing of mortality of the resistance and susceptible population of Myzus persicae, etofenprox was treated in the recommended concentration of 200ppm. Mortalities of resistance population were 16.7 and 36.7%, and susceptible population were 86.7 and 86.7% after 24 and 48 hours treatment, respectively. For the detect of cross resistance to other pyrethroids, 6 pyrethroids were examined. Mortalities of susceptible and resistance populations were 90 and 31% to deltamethrin, 92 and 23% to lambda cyhalothrin, 81 and 14% to cypermethrin, 70 and 20% to $\alpha$-cypermethrin, 29 and 28% to fenpropathrin, 84 and 29% to fenvalerate, respectively. It was showed that resistance populations were generally resistive to other pyrethroids. On the other hands, for recognized ecological characteristic of M. persicae susceptible and resistance populations life table was tested on the pepper leaves in the petri dish and on the plant in the pot. This results were showed that intrinsic rate of increase ($r_m$), net reproduction number ($R_0$) and generation time in day ($T_c$) were significantly different between two population in both tested. However, life span and reproduction period were slightly different between them. Otherwise, feeding behaviors were tested using EPG technique with non- and treated etofenprox. First potential drop time of susceptible and resistance population was 73.5 and 257.9 sec with non-treated and 93.3 and 1076.2 sec after treated, respectively. Electrical probing signals were 8.2 and 48.8 times with susceptible and resistance individuals after treated etofenprox, respectively. It was supposed that the resistance is more probings than susceptible population. After treated, total feeding time have more 6,728.9 sec on resistance than 965.5 sec on susceptible population. So, total non penetration time of susceptible population was 3,000 sec longer than resistance population.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.95-103
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• 1999

This experiment was conducted to investigate how the lactation regulation such as restricted-lactation and early weaning during the suckling period influences on ovarian functions and change in serum levels of progesterone in primiparous rats. All the rats were raised in the individual cage from a few days before parturition through the suckling period. The normal lactation(NL) groups were controled 8 pups. The restricted-lactation(RL) and weaned(W) groups were subdivided into 5 subgroups as RL0, RL5, RL10, RL15 and RL20 as well as W0, W5, W10, W15, and W20 according to the day of onset of suckling. The number of pups were regulated from 8 to 4 on experimental strating day in RL gropus, and also perfectly weaned on the each on-set day in W groups. The results obtained were summarized as follows: 1. During the whole suckling period of 25 days the pups in RL group grew significantly(P＜005) faster than those in normal-lactation(NL) group. The pups in earlier RL group grew significantly(P＜0.05) faster than those in later RL rats, and there was no found any significant difference in body weight of pups between RL20 and NL group. The gestation period and litter size were found to be 21.53$\pm$0.04 days and 13.75$\pm$0.07, respectively. 2. The estrous cycle was not expressed in the NL group through the whole suckling period. An irregular estrous cycle was found around day 20 in RL0 group, and the regular estrous cycles were exhibited continuously from day 10 in the day 0 weaned rats. 3. In the rats of NL group the serum progesterone concentration increased from 33.16$\pm$2.64ng/$m\ell$ on day 0 to 122.5$\pm$53.68 ng/$m\ell$ on day 10, and then decreased slightly to 97.30$\pm$3.21 ng/$m\ell$ on day 20, but then decreased abruptly. However, the serum level of progesterone decreased greatly(P＜0.05) in 5 to 10 days following suckling restriction in the rats from which suckling began to be under restriction on day 0 or day 15. In the early weaning group the significant ( (P＜0.05) decrease in progesterone concentration was found similarly in 48 hours following weaning in all the rats weaned on day 0 through day 20. It was suggested that lactation stimulation is a very pivotal on the function of ovary.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.291-298
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• 2002

This study was carried out to investigate the reproductive status and the effect of progesterone treatment on the recovery of reproductive disorders in Hanwoo. Hanwoo farms were surveyed the general management status, such as the type of barn, the feed intake, the incidence of reproductive disorders. The reproductive disorder cattle were treated 7 days insertion of control internal drug releasing for cattle (CIDR) and injection of PGF$_2$$\alpha$ at 1 day before removal. The recovery of reproductive disorders was assessed by determining the pregnancy following artificial insemination. The total number of surveyed Hanwoo farms was 127, and the total incidence rate of reproductive disorders was 19.7% (209/1,061). Compared to the herd size, the incidence rates of reproductive disorders in less than 10 heads (37.5%) was significantly (P<0.05) higher than in 10 to 20 heads (14.7%) and more than 20 heads (13.6%) of herd size per farm. The incidence rate of reproductive disorders in tie stall barn was significantly (P<0.05) higher than in free stall barn (30.4% vs. 14.7%), and even in free stall barn, that tended to decrease as the floor area was larger. The incidence rate of reproductive disorder by the parity was highest in heifer (50.7%), and that tended to decrease as the parity was increased. The distribution rate of the case of reproductive disorder in anestrus, recovery rate of reproductive disorders fellowing CIDR treatment was 75.1% (157/209). In the recovery rate of reproductive disorders by body condition score (BCS), BCS 1, 2 and 3 was significantly (P<0.05) higher pregnancy rate (85.7, 84.9 and 86.8%), and gross recovery rate in emaciated cattle was better than in obese cattle (BCS 4, 5). In conclusion, the incidence rate of reproductive disorders in Hanwoo raised in Youngju province area was 19.7%, and that tended to decrease as the herd size was increase because of increased farmer's attentions, and the floor area was larger. The majority of the case of reproductive disorders was anestrus. The recovery rate of reproductive disorders following CIDR treatment was 75.1%, and to optimize the recovery rate of reproductive disorders, cows and heifers were maintained BCS 1, 2 and 3 by moderate management.

• Korean Journal of Animal Reproduction
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• v.26 no.3
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• pp.215-221
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• 2002

Antioxidants(N-acetyl-1-cysteine, ebselen and glutathione) and growth factors(EGF, PDGF) were studied as a mean of increasing the development of porcine embryos produced by in vitro maturation (IVM) and in vitro fertilization(IVF). Porcine embryos developed to the 2~8 cell stage after IVF were cultured fer 6 to 7 days at 38.5$^{\circ}C$ in NCSU 23 medium containing antioxidants plus growth factors. Cell numbers of blastocysts were counted by fluorescence staining method. The developmental rate beyond morula stages in NCSU 23 containing NAC(1nm) or NAC(1nm) plus EGF(100ng/$m\ell$) or PDGF(5ng/$m\ell$) were 28.1, 32.3 and 35.3%, respectively. NAC plus PDGF group was slightly higher than control group(P>0.05). The developmental capacity in NCSU 23 containing ebselen(10 $\mu$M) or ebselen(10 $\mu$M) plus EGF(100ng/$m\ell$) or PDGF(5ng/$m\ell$) were 17.8, 36.9 and 40.3%, respectively Ebselen plus growth factor groups were significantly higher than control group(P<0.05). The developmental capacity in NCSU 23 containing glutathione(100 $\mu$M) or glutathione(100 $\mu$M) plus EGF (100ng/$m\ell$) or PDGF(5ng/$m\ell$) were 24.1, 30.5 and 27.7%, respectively. There were not difference in all experimental groups(P>0.05). In all experimental groups, there was no significantly differences on the cell number of blastocysts, but ebselen plus growth factor groups were significantly higher than control group. These studies indicate that antioxidants plus growth factors can increase the proportion of embryos that developed beyond morulae stage.

• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.10-12
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• 2000

Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$-subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was. efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to consist of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t63I or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632-653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17-fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.

• Korean journal of applied entomology
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• v.41 no.3
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• pp.211-216
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• 2002

The present study was aimed to examine the effect of different host plants on the biological property of cotton caterpillar, outbreak pest of cucurbit vegetables. The feeding and oviposition preferences toward cucumber and pumpkin were greater than those toward watermelon, oriental melon, and melon. The periods of egg and larva fed on oriental melon, melon, and pumpkin were longer than those on watermelon and cucumber. The longest pupal period was 10.5 days from cucumber. The hatching rate, pupation rate, emergence rate, and survival rate were observed from different host plants. The hatching rate was the highest on cucumber (87.2%) and the lowest on melon (72.8%). The pupation rate on watermelon and oriental melon (90.0% and 89.1%, respectively) was higher than that on cucumber (62.0%). The emergence rate on cucumber and pumpkin (93.5% and 92.0%, respectively) was higher than that on oriental melon (78.7%). The survival rate from hatching to emergence on watermelon (76.0%) was the highest, and the lowest on cucumber (50.0%). The adult period on melon (21.0 days) was the longest, and the shortest on cucumber (15.5 days) among 5 host plants. Average number of eggs per female on cucumber (281.8 eggs) was the highest, and the least on oriental melon (96.6 eggs). The survivorship on cucumber was the longest (30 days), and the shortest on pumpkin (17 days). The preoviposition period on oriental melon and melon (3.4 days) was longer than that on watermelon (2.1 days) and mean generation time in day (T) on melon was the longest (47.2 days) though they were not significant. The net reproductive rate per generation (R$_{o}$) on cucumber, 191.3, was the highest and the highest intrinsic rate of natural increase (r$_{m}$) was observed from cucumber as 0.127. All these results suggest that the growth ana reproduction of cotton caterpillar varies depending upon the kind of host plants. The analysis of the life table revealed that cucumber and pumpkin were the favorable host plants of cotton caterpillar.

• Korean journal of applied entomology
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• v.24 no.1 s.62
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• pp.15-18
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• 1985

Studies were made on the morphology and life cycle of the mite, Pyemotes tritici $Lagr{\acute{e}}z$-Fossot & $Montagn{\acute{e}}$ (Trombidiformes; Pyemotidea) ,parasitic on larvae of cigarette beetle, Lasioderma serricorne F., which is one of the most serious pests of stored tobacco, cigar, and cigarette in Korea. One generation time was $20.9{\pm}0.7$ days out of which $9.5{\pm}0.3$ days were spent for feeding and $10.3{\pm}0.8$ days for reproduction of progenies. A female of this insect-parasitic mite produced $56.7{\pm}6.9$ progenies during her reproduction period. The body size of a newly-laid male or female was $280{\mu}m$ long and $85{\mu}m$ wide. As female of this mite sucked on, their abdomen grew larger and larger to reach $825{\mu}m$ in width and $0.346mm^3$ in volume after $9{\sim}10$ days. By sucking the humor of a host, the abdomen of a female mite became almost a global shape in two days. The increase rate of abdominal width was the biggest on the second or the third day of feeding while the volume of abdomen reached to the largest on $6{\sim}8$ days after feeding. The largest number of the daily young produced on 4-th day after a female began to reproduce.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.533-540
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• 2000

Gonadal development, gametogenesis, reproductive cycle, gonad index, flesh weight rate, and first sexual maturity of the turban shell, Lunella coronata coreensis were investigated by histological observation. The materials used were collected monthly from the rocky intertidal zone of Daehang-ri, Buan-gun, Jeollabuk-do, on the west coast of Korea, from July 1998 to June 1999. Sex of L coronata coreensis was separate. The gonad was widely located in the spirals of the visceral mass buried in the digestive gland. The ovary and testis were composed of a number of oogenic follicles and speymatogenic follicles, respectively. Monthly variations in the gonad index increased from March ($23.86{\pm}3.73$) when the water temperature increased and reached the maximun in July ($49.76{\pm}6.47$). And then, the gonad index sharply decreased in September ($15.58{\pm}2.33$). The flesh weight rate ranged from $25.2{\%}$ to $32.3{\%}$, and its variation showed a similar pattern to the gonad index. Individuals $<5.9 mm$ in shell height could not take part in reproduction in both sexes. Percentages of first sexual maturity of female and male specimens ranging from $7.0{\~}7.9 mm$ in shell heights were $84.6{\%}\;and\;91.7{\%}$, respectively, and $100{\%}$ in those over 8.0 mm in shell height in both sexes took part in reproduction. By studying the monthly changes of the morphological features and sizes of germ cells during gametogenesis in the gonad, the reproductive cycle of this species could be devided into five successive stages: early active (December to April), late active (January to July), ripe (May to August), spawning (July to September), and recovery (September to March). The spawning period of this species was once a year between July and September, and the main spawning occurred in July when the seawater temperature reached above $24.8^{\circ}C$. The fully ripe eggs were $150{\~}160\;{\mu}m$ in diameter.

• Korean Journal of Animal Reproduction
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• v.26 no.1
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• pp.79-85
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• 2002

We investigated the optimal concentration and exposure time of cycloheximide(CHX) on development of activated porcine oocytes following electrical pulse(EP). After 42~44 h maturation, oocytes were treated with 0.1% hyaluronidase, and denuded cumulus cells by pipetting. Oocytes were stimulated by electric pulse (1.2 kV/cm, 30 $\mu$sec, 1 pulse) or incubated for 3, 5 and 7 h in cycloheximide (1, 5 and 10 $\mu\textrm{g}$/$m\ell$, respectively) following electric pulse, and cultured for 8 days. Cleavage rate of oocytes activated with 10 $\mu\textrm{g}$/$m\ell$ CHX following EP was significantly (P＜0.05) higher than those of 1 $\mu\textrm{g}$/$m\ell$ (86.8% vs. 74.4%). The developmental competence of oocytes incubated to 5 $\mu\textrm{g}$/$m\ell$ of CHX was significantly (P＜0.05) higher development to blastocysts (13.3%), compared with 10 $\mu\textrm{g}$/$m\ell$ of CHX (5.6%). When the oocytes were activated with 5$\mu\textrm{g}$/$m\ell$ CHX for 3, 5, and 7 h following EP, the cleavage rate of oocytes in 5 h group(86.6%) was significantly (P＜0.05) higher than that in 3 h group(73.2%). The developmental rate of oocytes to morula in 5 and 7 h groups(26.7% and 16.4%) were significantly (P＜0.05) high than that in 3 h group(14.5%). Matured oocytes were activated with electric pulse (EP) or electric pulse combined with cycloheximide (EP + CHX) and cultured for 8 days. The rate of cleavage and development to blastocyst (80.1% and 11.6%) of activated with EP group were similar to EP combined with CHX group. When activated with EP or EP combined with CHX, the mean cell number of blastocysts were less in the activated with EP (18.67$\pm$5.53) than in the activated EP combined CHX (20.71$\pm$6.16), but not significantly different. This results suggest that, when the porcine oocytes were activated with CHX following EP, the developmental rate of activated oocytes can be improved by treated with a concentration of 5 $\mu\textrm{g}$/$m\ell$ CHX for 5 h exposure time.

• Korean Journal of Animal Reproduction
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• v.22 no.1
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• pp.11-17
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• 1998

This study was carried out to investigate the in vivo developmental potential of mouse zona-hatched blastocysts (HBs). The HBs were cultured in vitro until day 5 and day 6 from zygotes produced in vivo and classified to small (S-HBs), medium (M-HBs) and large (L-HBs) on the basis of embryo diameters. The results obtained in these experiments were summarized as follows ; 1) when the blastocysts at day 4 were further cultured for $24\sim48hr$, HBs obtained at day 5 and day 6 culture in vitro were 29.1% and 22.8%, respectively. 2) Also, when the total cell number of HBs were counted, cell numbers of classified HBs on day 5 and day 6 to small ($77.3\pm5.3$, $59.6\pm4.4$), medium ($83.7\pm4.0$, $66.8\pm3.5$) and large ($100.7\pm2.6$, $88.9\pm3.8$) were increased as their size increases. Especially, there were significantly different between S-HBs and L-HBs (p<0.01). 3) In addition, when the classified HBs were transferred into when the classified HBs were transferred into day 3 pseudopregnant recipients, the pregnancy and implantation rates of S-HBs (28.6%, 15.7%), M-HBs (44.4%, 30.9%) and L-HBs (62.5%, 49.1%) at day 5 were increased as their size increases. However, this pattern was not showed in embryo transfer of day 6 HBs. But, when the live fetuses formation against total implantation rates were observed, the result (87.5%) of S-HBs of day 5 was significantly higher than that of the others (p<0.01). Therefore, this study demonstrates that in vitro cultured healthy HBs can not only be developed normally with good pregnancy rates, implantation rates and live fetuses formation, but also served as a fundamental data for utility of supernumerary HBs in human blastocyst transfer.