• Title/Summary/Keyword: 3D Morphology

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Reproductive Cycle of Ribbed Gunnel Dictyosoma burgeri (그물베도라치 Dictyosoma burgeri의 생식주기)

  • Jin, Young Seok;Han, Jae Il;Park, Chang Beom;Lee, Chi Hoon;Kim, Byung Ho;Baek, Hea Ja;Kim, Hyung Bae;Lee, Young-Don
    • Korean Journal of Ichthyology
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    • v.19 no.1
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    • pp.8-15
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    • 2007
  • The morphology of gonad and reproductive cycle of ribbed gunnel (Dictyosoma burgeri) were investigated on the basis of histological observation. The specimens were monthly sampled in the coastal waters of Jeju from November 2001 to February 2003. The ovaries and testis of this species are categorized as cystovarian and lobule type, respectively. The gonadosomatic index (GSI) of female increased in November and maintained high values from December to February. The GSI of male was similar to that of female although it was decreased in February. The reproductive cycle can be grouped into the following successive stage in the ovary: growth (October to November), mature (November to February), spawning (January to February), and degenerating and recovery (March to September). And in the testis, the stage observed were: multiplication (August to November), growth (November to January), mature and spawning (November to February), and degenerating and recovery (January to September). The minimum maturation size of D. burgeri was over 15.0 cm and fecundity ranged from 2,194 to 6,581 eggs. The relationship between the fecundity and fish body was calculated in the fecundity (F) equation as: $F=0.4057TL^{3.1425}$ ($R^2=0.7621$) for total length (TL); $F=149.88BW^{0.9579}$ ($R^2=0.7982$) for body weight (BW), respectively. The fecundity was correlated positively with TL and BW. The histological observations of the gonads suggested that major spawning of this species probably occurs between January to February, when low water temperature ($13{\pm}0.3^{\circ}C$) period.

Autoradiographic Studies on the Inhibitory Effect of Dibutyryl Cyclic AMP on Mouse Oocyte Maturation in Vitro (Dibutyryl Cyclic AMP가 생쥐여포난자의 성숙에 미치는 억제효과에 관한 자기방사법적 연구)

  • Choi, Choon-Keun
    • Applied Microscopy
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    • v.7 no.1
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    • pp.21-43
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    • 1977
  • This experiment was undertaken in order to localize the labeled dbcAMP (dibutyryl cyclic AMP) in oocytes whose development has been suppressed by cold dbcAMP for 6 or 19 hours in vitro. Mouse oocytes were obtained from the ovaries of 3-4 week old A strain female mice, by puncturing the Graafian follicles in the modified Krebs-Ringer bicarbonate salt solution under the dissecting microscope. Those oocytes which have intact germinal vesicle were cultured in the basic culture medium supplemented with 0.4% bovine serum albumin (BSA). Cultivation of the oocytes was carried out in a microtube developed by Cho (1974). The cultures were then incubated in a humidified 5% $CO_2$ incubator maintained at $37^{\circ}C$ for 6 or 19 hours (Donahue, 1968). DbcAMP was added to culture medium for a final concentration of 100ug/ml, and $^3H-dbc$ AMP (specific activity 13 Ci/mM) for a final concentration of $40{\mu}Ci/ml$ was also added to the medium. For electron microscopic autoradiography, those oocytes recovered from the culture were washed with phosphate buffer (pH 7.4), and immediately prefixed in a 2.5% glutaraldehyde overnight and postfixed for 2 hours at $4 ^{\circ}C$ in 1% osmium tetroxide in phosphate buffer with pH 7.4 (Palade, 1952). After fixation, the materials were dehydrated in graded alcohol series and embedded in Epon 812 mixture based on the standard procedures (Luft, 1961). The thin sections $600-700{\AA}$ thick were mounted on the grids of 200 meshes. The grids containing sections were coated with a nuclear emulsion Kodak NTB-3 and stored in a cold dark box (at $4^{\circ}C$) for 3 weeks. After exposure, the samples were developed with Kodak D-19 and stained with uranyl acetate and lead citrate. Routine observation was made with Hitachi HU-11E electron microsocope. The results of the observation were as followings: 1. It was found that the labeled dbcAMP penetrated the egg plasma membrane and dispersed at random in the cytoplasm. 2. It was also observed that most of the labeled dbcAMP was attached to microfibrillar lattices portion of the oocyte cytoplasm. There fore, it is presumed that the receptor of the dbcAMP is localized in the microfibrillar lattices of the oocyte. 3. It also seems that some other cell organells such as mitochondria, Golgi complex, cortical granules are not directly related to the action of the dbcAMP. 4. The labeled dbcAMP was neither observed in the membrane nor in the nucleus. Therefore, it seems that there is no relationship between the concentration of dbcAMP and the nuclear membranous permeability. 5. There was no difference in number of dbcAMP particles when oocytes were cultured for 6 hours and 19 hours. 6. However, it was observed that, in same of the oocytes suppressed in germinal vesicle by dbcAMP for 19 hours, cell organells were moved and concentrated to a small portion of the cytoplasm, and that the morphology of the organells greatly changed to an abnormal. form. Therefore, it is supposed that those oocytes were in the process of degeneration. From the above results, it is expected that dbcAMP penetrated the egg membrane and was bound to the receptor which seems to be located in the microfibrillar lattiees portion, and that this dbcAMP-receptor complex inhibited some enzyme system of the oocytes which are essential for the germinal vesicle breakdown.

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Developmental Capacity of Bovine Follicular Oocytes after Ultra-Rapid Freezing by electron Microscope Grid II.Cryopreservation of In Vitro Matured Bovine Oocytes (Electron Microscopic Grid를 이용한 초급속 동결이 소 난포란의 발달능에 미치는 영향. II. 체외 성숙된 소 미수정란의 동결에 관한 연구)

  • 김은영;김남형;이봉경;윤산현;박세필;정길생;임진호
    • Korean Journal of Animal Reproduction
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    • v.22 no.1
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    • pp.1-9
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    • 1998
  • This study was carried out to confirm whether the developmental capacity of bovine mature oocytes frozen ultra-rapidly using electron microscopic(EM) grids and EFS30 can be obtained, and whether the cryoprotectants and the freezing method used in this study effect detrimentally to the bovine oocytes by indirect immunocytochemistry. As freezing solution, we used EFS30 which consisted of 30% ethylene glycol, 0.5 M sucrose, 18% ficoll and 10% FBS added in D-PBS. The results obtained in this experiment were summarized as follows: When the effects of cryoprotectant and freezing procedure on the microtuble, micrfilament and chromatin morphology of oocytes were evaluated using indirect immunocytochemistry, the results of freezing as well as exposure group were not different with that of the control oocytes. When the fertilization abnormality after ultrarapid freezing of bovine mature oocytes was examined by Hoechst staining, the rates of total penetration(96.7, 9.0%), normal two pronuclei formation(74.6, 68.9%) and mean number of sperm / oocyte(1.50, 1.44) were not different between control and freezing group. In addition, when the developmental capacity of frozen-thawed of oocytes(85.5%) was survived, 74.5% of them were cleaved and 31.4% of cleaved embryos were developed to blastocyst. These data were similar to those of the control(76.0%, 34.6%) and exposure(74.5%, 33.0%) except survival rates. Also, when the total cell number of blastocysts produced from the each treatment at day after IVF was examined by hoechst staining, there were not different among groups. There results demonstrate that developmental capacity of frozen-thawed bovine mature oocytes can be successfully obtained by ultra-rapid freezing method using EM grid and EFS30 solution.

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A New Forma of Acanthopanax Species(I) (신품종(新品種)을 포함한 한국산(韓國産) Acanthopanax속(屬)의 분류(分類)(I))

  • Yook, Chang-Soo;Lee, Dong-Ho;Seo, Yoon-Kyo
    • Korean Journal of Pharmacognosy
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    • v.7 no.3
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    • pp.179-190
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    • 1976
  • 1. The Korean Acanthopanax genus includes 12 kinds consisting of 9 species and 3 forma. 2. The Korean Oga-pi which is on market sale has been used as bark for the medicinal purpose, and Oga-pi shall use Radicis Cortex. That is why it is basic rule that herbalogy shall use Radicis Cortex. 3. The origin of Oga-pi on sale is Acanthopanax sessiliflorum forma chungbunensis C.S. Yook. 4. $C_{HUNG}\;and\;N_AKAI'S}$ report on A. koreanum told us that there are brown hair on the mid-leaf junction, but in addition to it, our investigation was resulted in the fact that there are thorn along mid-rib sometimes. 5. 2 kinds of new forma are similar to A. sessiliflorum, but are different in the view-point of chemotaxonomy, compared with A. sessiliflorum. In its morphology, we can find some difference between 2 kinds of new forma and A. sessiliflorum. Our effort of examination on documents tell us that the all plants growing in the central part of our country is A. sessiliflorum forma chungbunensis C.S. Yook. The one which has thorn on both side among the plants collected in Mt. Dukyu, is called A. sessiliflorum forma nambunensis C.S. Yook. 6. A. sessiliflorum is growing in the southern part in Korea, and most Chungbu Oga-pi A. sessiliflorum forma chungbunensis in the central part of our country. For the convenience of our study, the key of Korean Acanthopanax plant is classified into, I-IV, as shown on the following items: I. No hair on both side of leaf A. Flower stalk is longer than petiole, and there are thorn under the petiole (5-7 stigma).${\cdots}A.\;sieboldianum$. B. Flower stalk is longer than petiole, or same length. The serration lie down, and the stem has short thorn (stigma is divided into 3 part).${\cdots\;\cdots}A.\;seoulense$ II. There are a lot of thorn or hair on back of leaf. A. A lot of thorn and hair on the vein of leaf back, and a number of small thorn on petiole.${\cdots}A.\;chiisanensis$. B. There are thorn on the vein of leaf back.${\cdots\;\cdots}A.\;sessiliflorum\;forma\;chungbunensis.$ III. There are hairs on both side of leaf. A. There are small hairs on the back of leaf.${\cdots\;\cdots}A.\;sessiliflorum.$ B. There are small hairs on both side of leaf.${\cdots\;\cdots}A.\;sessiliflorum\;f.\;nambunensis.$ C. There are thick hairs on junction of main vein on back of leaf.${\cdots\;\cdots}A.\;koreanum.$ D. There are brown hairs on vein of leaf back, and brown hairs on small petiole.${\cdots\;\cdots}A.\;rufinerve.$ E. There are shrunk hairs in grey-brown on back of leaf, and tense hairs on new branch (one stigma).${\cdots\;\cdots}A.\;divaricatum.$ IV. There are long thorn, just like needles, on the stem and petiole. A. Long needle grows on whole stem tensely, and long needles on petiole.${\cdots\;\cdots}A.\;senticosus.$ B. There are no needles, just like needles aid hairs on petiole, and needles grow on the stem thinly.${\cdots\;\cdots}A.\;asperatus.$ C. There are no needle on small brarch, leaf and inflorescence are larger than A. senticosus. ${\cdots\;\cdots}A.\;senticosus\;forma\;inermis.$.

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Morphological Variations in Relation to Geographical Distribution of Pond Smelt, Hypomesus olidus Pallas (한국산 빙어의 지리적 형태변이에 대하여)

  • Ryu Bong Suk;LEE Kyung Ro
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.14 no.3
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    • pp.179-188
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    • 1981
  • The authors made an investigation concerning the geographical distribution and some major differentiations in morphological characteristics associated with the each habitat, of the pond smelt, Hypomesus olidus, which was introduced into Korea more than 50 years ago. Major characteristics utilized for the comparison study were upper jaw (maxillary), number of fin rays, scale structure, vertebral count, number of pyloric caeca, number of gill rakers, and the relative measurements of these and other internal characters. 1. The main areas of natural distribution are Paro Lake, Soyang Lake, Han River, Euirim Lake, and Ogjeong Lake (or Unam Lake) and the tributaries of these waters. 2. Morphological variations varied when the mean values of measurements from each area were compared with the standard measurement value by mosaic comparison, and in some instances a significant variation was found. 3. The most significant variations were found in the number of fin rays of pectoral and anal fins; the lengths from the tip of snout to the origin of pectoral fin, from snout to ventral fin, and from snout to anal fin, relative to standard body length; eye depth relative to head length; upper jaw: the number of pyloric caeca and the scale structure. Variations, on the other hand, by each habitat were not clear in the numbers of ventral and dorsal fin rays, gill rakers, vertebrae and lateral line scale : and the depth of caudal peduncle and distance from the tip of snout to the origin of dorsal fin relative to standard body length. 4. The scales of pond smelt showed some differences in the shape of scales, the shape and position of the focus and the number of ridges according to the scale positions on the body. No radii were present. The relations between longitudinal and transverse diameters of the scale suggest that the pond smelts of Soyang Lake and Un-am Lake are closely related, and those of Han River and Euirim Lake are also closely related. 5. The geographical variations in morphology of the pond smelt seem to have resulted from the variations in turbidity, water temperature, salinity (rather conductivity) and currents. 6. From the results obtained, it may be concluded that such factors as supramaxillary, relation between scale length and its breadth, number of caudal vertebrae and eye depth relative to head length may be used as the key characters for the classification of geographical varieties of Pond smelt.

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Recruitment and Succession of Riparian Vegetation in Alluvial River Regulated by Upstream Dams - Focused on the Nakdong River Downstream Andong and Imha Dams - (댐 하류 충적하천에서 식생이입 및 천이 - 낙동강 안동/임하 댐 하류하천을 중심으로 -)

  • Woo, Hyo-Seop;Park, Moon-Hyung;Cho, Kang-Hyun;Cho, Hyung-Jin;Chung, Sang-Joon
    • Journal of Korea Water Resources Association
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    • v.43 no.5
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    • pp.455-469
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    • 2010
  • Changes of geomorphology in alluvial river and vegetation recruitment on its floodplain downstream from dams are investigated both qualitatively and quantitatively focusing on the downstream of Andong dam and Imha dam on the Nakdong River. Results of the analyses of river morphology and bed material in the study site show a general trend of riverbed degradation with a max scour of 3 m and bed material coarsening from pre-dam value of 1.5 mm in D50 to post-dam value of 2.5 mm. Decrease in bed shear stress due to the decrease in flood discharge have caused vegetation recruitment on the once-naked sandbars. As result, the ratio of area of vegetated bars over total area of bars has drastically changed from only 7% in 1971 before the Andong dam (constructed in 1976) to 25% after it, and increased to 43% only three year after the Imha dam (constructed in 1992) and eventually to 74% by 2005. Analysis of the vegetation succession at Wicjeol subreach, one of the three subreaches selected in this study for detailed investigation, has clearly shown a succession of vegetation on once-naked sand bars to a pioneering stage, reed and grass stage, willow shrub and eventually to willow tree stages. At the second subreach selected, two large point bars in front of Hahoe Village seem to have maintained their sand surfaces without a signifiant vegetation recruitment until 2005. The sand bars, however, seem to have been invaded by vegetation recently, which warns river managers to have a countermeasure to protect the sand bars from vegetation invasion in order to conserve them for the historical village of Hahoe. On the other hand, recruitment and establishment of vegetation on the sand bars by artificial disturbance of the river, such as damming, can create an unique habitat of backmarsh in the sandy river, as shown in the case of Gudam Wetland, and may increase the biodiversity as compared with relatively monotonous sand bars. Last, the premise in this study that decrease in flood discharge due to upstream dams and decrease in bed shear stress can induce vegetation recruitment on the naked sand bars in the river has been verified with the analyses of the distribution of dimensionless bed shear stress along the selected cross section in each subreach.

Effects of Feeding and Processing Methods of Diets on Performance, Morphological Changes in the Small Intestine and Nutrient Digestibility in Growing-Finishing Pigs

  • Yang, J.S.;Jung, H.J.;Xuan, Z.N.;Kim, J.H.;Kim, D.S.;Chae, B.J.;Han, In K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.10
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    • pp.1450-1459
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    • 2001
  • These experiments were conducted to investigate the effects of different feeding and processing methods of diets on performance, morphological changes in the small intestine and nutrient digestibility of growing-finishing pigs. One-hundred fifty growing pigs ($Yorkshire{\times}Landrace{\times}Duroc$; initial body weight of $23.33{\pm}0.75kg$) and one-hundred twenty finishing pigs ($Yorkshire{\times}Landrace{\times}Duroc$; initial body weight of $59.22{\pm}0.56kg$) were used in Exp. 1 and Exp. 2, respectively. Pigs were grouped on the basis of body weight and gender, and randomly allotted into 6 different treatments with 5 replications in each treatment in a $2{\times}3$ factorial arrangement. Treatments were 1) dry feeding with a mash diet (DM), 2) dry feeding with a pelleted diet (DP), 3) dry feeding with an expanded crumble diet (DEC), 4) dry/wet feeding with a mash diet (WM), 5) dry/wet feeding with a pelleted diet (WP), and 6) dry/wet feeding with an expanded crumble diet (WEC). In Exp. 1 (growing phase), there was no significant difference in average daily gain (ADG) and average daily feed intake (ADFI) among treatments during the entire experimental period, but feed conversion ratio (FCR) was significantly (p<0.05) improved in pigs fed pelleted diets regardless of feeding method. FCR was best in pigs fed a DP diet and worst in pigs fed a WM diet. Pigs fed a pelleted diet showed a 6.2% or 4.0% improvement in FCR compared with those fed a mash diet or an expanded crumble diet. Water disappearance was not significantly affected by dry/wet feeding or feed processing. Significant differences in villus height were not found among treatments, but villus height tended to be improved by dry/wet feeding. Dry/wet feeding or feed processing did not affect crypt depth. Digestibilities of calcium and phosphorus were significantly (p<0.05) improved in pigs fed an expanded crumble diet compared with pigs fed mash diets. Especially, pigs fed a WEC diet digested 8.1% more P than those fed a DM diet. Feed cost per kg weight gain (FCG) tended to be increased by dry/wet feeding rather than dry feeding. In Exp. 2 (finishing phase), ADG and ADFI were not significantly different among treatments, but a significant difference in FCR was found among feed processing forms. The best FCR was obtained in pigs fed a pelleted diet. Pigs fed a DP diet showed a 11.3% improvement compared with those fed a DEC diet. Water disappearance was significantly (p=0.0408) decreased by feeding the mash diet. However, water disappearance was not affected by dry/wet feeding during the finishing period. The villus height and crypt depth were not significantly different among treatments. However, crypt depth tended to be decreased by dry/wet feeding at the mid part of the small intestine. Fat digestibility was improved by dry feeding rather than dry/wet feeding, and was improved by 4.8% by feeding pellet diets compared with expanded crumble diets. Except for carcass grade, carcass characteristics were not significantly (p<0.05) different among treatments. Carcass grade was the best in pigs fed a WP diet. Feed cost per kg weight gain (FCG) was significantly decreased in pigs fed a pelleted diet compared with those fed an expanded crumble diet, and tended to be decreased by dry/wet feeding. In conclusion, these studies suggest that feeding the pelleted diet to growing-finishing pigs can be beneficial in terms of FCR and production cost. Dry/wet feeding can be helpful for the maintenance of villus height, but may not be reflected in improved growth performance or reduction of production costs.

Acceleration of Early Embryonic Development by Induction of Acrosome Reaction in Intracytoplasmic Sperm Injection (세포질내 정자주입술 시행시 정자의 첨체반응이 수정란의 초기 발생과 임신율에 미치는 영향)

  • Lim, Y.J.;Lee, D.R.;Lee, J.E.;Kim, H.J.;Paik, H.R.;Yoon, H.S.;Shim, H.N.;Cho, J.H.;Roh, S.I.
    • Clinical and Experimental Reproductive Medicine
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    • v.24 no.3
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    • pp.311-318
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    • 1997
  • Bypassing acrosome reaction and fusion process in intracytoplasmic sperm injection(ICSI), most of injected spermatozoa still contain intact acrosome contents and plasma membrane. It Is not known yet what acrosome contents and plasma membrane of spermatozoa have effect on the development of embryo. For further understanding of fertilization process after ICSI, we studied the time of pronucleus formation, disappearance and first cleavage in human zygote, and pregnancy rate in relation to acrosome reaction rate of spermatozoa after ICSI. Seventy cycles undergoing ICSI program were randomly selected. Sperm suspension from 38 cycles were treated 50% human follicular fluid(hFF) for 3 hours in order to induce acrosome reaction, others were not treated as control. Acrosome reaction in hFF treated and non-treated group was assessed by fluorescein isothiocyanate(FITC)-conjugated Arachis hypogea(PNA) and Pisum sativum agglutinin(PSA). Oocytes were classified into 'good' and 'poor' according to their morphology. After ICSI, fertilization of oocytes were assessed by detection of two pronuclei at 16 hours. The pronuclei disappearance and first cleavage of zygotes were observed at 24 hours, and then embryos were transferred to uterus after culture for 72 hours. The rate of acrosome reaction of spermatozoa in hFF treated group was significantly higher than that in control(p<0.01). Fertilization rates of good oocytes were not different both control and hFF treated group(81.3%(174/206) vs. 72.1%(102/130)). But, in poor oocytes, the fertilization rates in hFF treated group(72.1%(149/183)) were increased compared than those of control group (63.6%(98/140), p<0.01). In either good or poor oocytes, the rates of pronuclei disappearance in hFF treated-spermatozoa injected oocytes were higher than control (59.1%(103/174), 56.4%(84/149) vs. 32.4%(33/102), 37.8%(37/98), p<0.01). Also, the rates of thirst cleavage were increased in hFF treated group (31%(54/174), 24.1%(36/149)) compared than those of control group (10.8%(11/102), 13.2%(13/98), p<0.01). The pregnancy rates of hFF treated group (42.1%(16/38)) were slightly higher than control group (28.1%(9/32), p>0.05). But, the pregnancy rate of group which possessed more than one cleavaged zygote at 24 hours was higher than group which did not (45.2%(19/42) vs. 21.4%(6/28), p<0.05). From these results, the development of zygotes were faster in higher acrosome reacted sperm group than lower acrosome reacted sperm group after ICSI. Our results may be explained that acrosomal membrane and plasma membrane are easily detached from spermatozoa in acrosome reacted spermatozoa compared with acrosome intact sperm in the cytoplasm of oocyte during pronuclear formation. We conclude that the injection of acrosome reacted spermatozoa will increase the pregnancy rate as they can induce fast embryonic development in ICSI.

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G-, C-, and NOR-banding of Korean Native Pig Chromosomes (한국재래돼지의 G-, C-, 및 NOR-banding)

  • Sohn, S.H.;Kweon, O.S.;Baik, K.H.;Jung, W.;Cho, E.J.;Kang, M.Y.
    • Journal of Animal Science and Technology
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    • v.45 no.6
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    • pp.901-910
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    • 2003
  • Using the G-, C-, and NOR-banding techniques, a karyotyping for Korean Native Pig was performed. Blood samples were collected from 50 male Korean Native Pigs that had been bred at the National Livestock Research Institute and then blood cells were prepared from in vitro cultures followed by karyotyping; G-, C-, and NOR-banding patterns of metaphase chromosomes were analyzed. The karyotype of Korean Native Pig is 38, XX or XY which consists of 5 pairs of submetacentric chromosomes(Group I), 2 pairs of acrocentric chromosomes with short p-arm(Group II), 5 pairs of medium metacentric chromosomes(Group III), 6 pairs of acrocentric chromosomes(Group IV) and metacentric X and Y sex chromosomes. On GTG-banding, the Korean Native Pig exhibited a typical and identical banding pattern in each homologous chromosomes. Overall chromosomal morphology and positions of typical landmarks of the Korean Native Pig were virtually identical to those of Committee for the Standardized Karyotype of the Domestic Pig(CSKDP). However, numbers of G-bands of the Korean Native Pig chromosomes were more than those of CSKDP. In chromosomes 1, 3, 5, 6, 7, 8, 13, 14, 15, 16, 17, 18 and X, the Korean Native Pig exhibited more separated bands as compared with CSKDP. In C-banding patterns, although the quantity of heterochromatin was variable in each chromosome, most of the Korean Native Pig chromosomes had heterochromatic C-bands on centromeres. However, the heterochromatic C-band was constantly observed on the whole Y chromosome. In AgNOR staining, the NORs were located at centromeres on the chromosomes 8 and 10. The number of NORs per metaphase ranged from 2 to 4 giving a mean value of 2.13. The number of NORs were distributed on all chromosome pair 10 but not on chromosome 8. The sizes of NORs were also differed between homologous chromosomes 8. Numbers of NORs of Korean Native Pig were significantly higher than those of Yorkshire. The pattern of pig NORs was polymorphic in breeds, individuals and cells, especially on chromosome 8.

THE EFFECTS OF DIETARY CONSISTENCY ON THE TRABECULAR BONE ARCHITECTURE IN GROWING MOUSE MANDIBULAR CONDYLE : A STUDY USING MICRO-CONFUTED TOMOGRAPHY (성장 중인 쥐에서 음식물의 경도가 하악 과두의 해면골에 미치는 영향 : 미세전산화 단층촬영을 이용한 연구)

  • Youn, Seok-Hee;Lee, Sang-Dae;Kim, Jung-Wook;Lee, Sang-Hoon;Hahn, Se-Hyun;Kim, Chong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.2
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    • pp.228-235
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    • 2004
  • The development and proliferation of the mandibular condyle can be altered by changes in the biomechanical environment of the temporomandibular joint. The biomechanical loads were varied by feeding diets of different consistencies. The purpose of the present study was to determine whether changes of masticatory forces by feeding a soft diet can alter the trabecular bone morphology of the growing mouse mandibular condyle, by means of micro-computed tomography. Thirty-six female, 21 days old, C57BL/6 mice were randomly divided into two groups. Mice in the hard-diet control group were fed standard hard rodent pellets for 8 weeks. The soft-diet group mice were given soft ground diets for 8 weeks and their lower incisors were shortened by cutting with a wire cutter twice a week to reduce incision. After 8 weeks all animals were killed after they were weighed. Following sacrifice, the right mandibular condyle was removed. High spatial resolution tomography was done with a Skyscan Micro-CT 1072. Cross-sections were scanned and three-dimensional images were reconstructed from 2D sections. Morphometric and nonmetric parameters such as bone volume(BV), bone surface(BS), total volume(TV), bone volume fraction(BV/TV), surface to volume ratio(BS/BV), trabecular thickness(Tb. Th.), structure model index(SMI) and degree of anisotropy(DA) were directly determined by means of the software package at the micro-CT system. From directly determined indices the trabecular number(Tb. N.) and trabecular separation(Tb. Sp.) were calculated according to parallel plate model of Parfitt et al.. After micro-tomographic imaging, the samples were decalcified, dehydrated, embedded and sectioned for histological observation. The results were as follow: 1. The bone volume fraction, trabecular thickness(Tb. Th.) and trabecular number(Tb. N.) were significantly decreased in the soft-diet group compared with that of the control group (p<0.05). 2. The trabecular separation(Tb. Sp.) was significantly increased in the soft-diet group(p<0.05). 3. There was no significant differences in the surface to volume ratio(BS/BV), structure model index(SMI) and degree of anisotropy(DA) between the soft-diet group and hard-diet control group (p>0.05). 4. Histological sections showed that the thickness of the proliferative layer and total cartilage thickness were significantly reduced in the soft-diet group.

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