We investigated the toxic effects of difenoconazole on the development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of difenoconazole (0-30 μM). LC100 for difenoconazole was 30 μM, and the LC50 determined by probit analysis was 27.19 μM. Exposure to difenoconazole concentrations ≥5 μM resulted in 10 different types of severe external malformation. Histological examinations revealed dysplasia of the eye, heart, liver, somatic muscle, and swelling of the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells were normally induced at a high frequency by mSCF and activin A. However, the induction of blood cells was strongly inhibited by the addition of difenoconazole. Electron micrographs of tested embryos showed the degeneration of somatic muscle and the shrinkage of microvilli on pronephric duct. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). It revealed that the expression of the blood-specific marker(β -globin Ⅱ) and muscle-specific marker (XMA) were more strongly inhibited than the neural-specific marker(XEn2) by the addition of difenoconazole.

In the present study, to understand the process of abnormal pigmentation (hypermelanosis) on the blind side of olive flounder P. olivaceus during early development, we investigated an time that staining on the blind side is initially observed with the naked eyes, counted the number of stained spot on the blind, and calculated the ratio of area stained on the blind side, and the ratio of fish pigmented on the blind side with growth. The present experiment was initiated at 24-day after hatching (dah), just after the starting of metamorphosis, in which fish mean size is total length (TL) 12.4±0.2 ㎜ and body weight (BW) 19.9±0.7 ㎎, and was finalized at 94-dah (TL 72.0±0.6 ㎜, BW 3,912.3±119.4 ㎎). The experimental animals were reared in FRP tank at 20±0.5℃ in water temperature and 30.9±0.1 psu. The experimental animals were feed with rotifer, Artemia nauplii and commercial food according growth stage. As results, the pigmented spots are composed with adult-type melanophores. The first spot was found in microscopy level at 38-dah (TL 18.3±0.4 ㎜, BW 57.6±4.1 ㎎), but the first staining spot observed with the naked eye was found 52-dah (TL 37.6±0.5 ㎜, BW 534.2±30.9 ㎎) around the pectoral fin and the caudal peduncle. The pigmented spots became more distinctive and expanded around the edge of rear on the blind side. The number of spots and the ratio of area stained on the blind side sharply increased between 31-dah and 80-dah, and between 66-dah and 94-dah, respectively. The ratio of fishes stained on the blind side increased between 45-dah and 73-dah, and then was stagnated to 94-dah. Therefore, these results concluded that the pigmentation on the blind side of olive flounder is not an temporary and reversible color change but an irreversible abnormal phenomenon that pigment cells is continuously differentiated on the blind side with growth for early development just after metamorphosis in artificial culture conditions.

We investigated the toxic effects of tebuconazole on development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of tebuconazole(0-100 μM). LC100 for tebuconazole was 100 μM, and the LC50 determined by probit analysis was 82.35 μM. The exposure to tebuconazole concentrations ≥40 μM resulted in 11 different types of severe external malformations including gut dysplasia. Histological examinations revealed various dysplasia in the eye, heart, liver, intestine, somatic muscle, and in the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells are generally induced at a high frequency by the combination of mSCF and activin A, however, the induction of blood cells was strongly inhibited by the addition of tebuconazole. Electron micrographs of tested embryos showed many of multivesicular bodies and dysplasia of photo-receptive cell, however, the somatic muscle degeneration was not severe. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction and revealed that expression of the blood-specific marker, β globin Ⅱ and muscle-specific marker, muscle actin were more strongly inhibited than the neural-specific marker, XEn2.

Three-year-old seedlings of susceptible Pinus densiflora and resistant Pinus x rigitaeda were each inoculated with the pinewood nematode, Bursaphelenchus xylophilus, to compare disease development. Needle dehydration was evident on seedlings of P. densiflora by 20 days after inoculation, 10 days earlier than this symptom was observed on P. × rigitaeda. Xylem drying was more frequent in seedlings of P. densiflora than in that of P. × rigitaeda between 20 and 60 days after inoculation. No significant differences were found between P. densiflora and P. × rigitaeda for stem water content or for stem and leaf relative water content in current-year branches after nematode inoculation, but the average number of B. xylophilus recovered from stems differed significantly between the two groups. The number of B. xylophilus recovered from stems was negatively correlated with the stem water content and with stem and leaf relative water content. By the time the experiment was terminated at 60 days after inoculation, all 3 of the last group of P. densiflora seedlings had died, but 2 of the 3 remaining P. × rigitaeda hybrid seedlings were still alive. Additional studies are needed to further explore the specific mechanisms preventing nematode multiplication in the seedlings of resistant P. × rigitaeda.

p63은 다양한 상피 조직의 줄기세포와 전구세포에 존재한다는 사실이 잘 알려져 있으나, 치아 형성, 특히 사기질과 뿌리 형성시기에서의 p63 위치느 ㄴ아직 연구해야 할 과제로 남아 있다. 본 연구에서는 p63이 치아 발생 동안 치아상피에 편재하여 나타나는 것을 면역조직화학 기법을 이용하여 확인하였다. p63은 피부, 모낭, 구강점막 그리고 턱밑샘 도관을 포함하는 상피의 바닥층과 바닥위층에 위치하였다. 그러나 치아 부위에서는 치아관의 모든 세포, 사기질기

콘크리트는 초기재령에 있어서 수분의 증발 및 이동으로 소성 및 건조수축 등의 수축현상이 발생한다. 국내에서는 아령형 구속건조수축몰드를 활용한 콘크리트의 건조수축 균열 평가방법을 KS에서 규격화하여 활용하고 있으나 이는 균열발생시점 및 구속수축응력을 평가하는 방법으로 균열발생량에 관한 정량적 평가는 어려운 실정이다. 이에 본 연구에서는 콘크리트의 수축변형거동 및 균열발생량에 대한 정량적 데이터를 확보하기 위하여 판상-링형 구속시험방법을 개발하고 시험체 치수가 콘크리트의 수축균열에 미치는 영향을 검토하여 판상-링형 구속시험방법의 최적 시험체 치수 도출 및 수축균열특성에 관한 정량적 평가방법을 제안하고 그 적용성을 검증하고자 한다.

전어, Konosirus punctatus의 부화후부터 부화후 30일까지의 전장, 두장, 두고, 안경, 망막 두께 및 렌즈직경의 성장은 비례직선적이었다. 전장에 대한 두장 및 두고의 상대 성장, 두장에 대한 안경 및 렌즈직경의 상대 성장, 두고에 대한 안경 및 렌즈직경의 상대 성장, 그리고 망막 두께에 대한 안경, 렌즈직경, 두장, 두고의 상대 성장은 높은 상관계수를 보이는 상대성 장식을 보였다. 눈은 부화 후 9일에 완전히 형성되었으며 렌즈, 신경섬유

본 연구는 유아교육기관의 질적 수준에 대해 수요자 관점의 학부모 중심 유아교육기관 평가도구를 개발하는데 그 목적이 있다. 학부모중심 유아교육기관 평가도구를 개발하기 위한 예비척도의 문항은 5개의 평가 영역을 설정하고 그 하위 문항에 대한 110개 평가문항을 제작하여 유치원의 학부모를 대상으로 하여 각 문항이 유아교육기관 평가에 있어 얼마나 중요한지에 대해 5단계의 숫자로 평정하도록 하였다. 연구문제를 검증하기 위하여 수집된 자료는 SPSS 7.5 프로그램을 이용하여 문항의 중요도의 평균 표준편차, 범위를 산출하였고, Varimax 회전 방법을 사용하여 요인분석을 하여 Cronbach α계수를 산출하였다. 연구결과 예비척도는 대부분 높은 중요도 및 신뢰도를 나타냄으로서 내용 타당도 및 구인 타당도를 입증하였고, 문항의 중요도와 Cronbach α계수 면에서 바람직한 104개의 문항을 최종적으로 선정함으로써 학부모중심 유아교육기관 평가도구를 개발하였다.

조피볼락 갑상선 여포의 원시세포는 모체내 부화자어의 구강 아래쪽에 존재하는 때의 원형 여포 안에 존재하였다. 갑상선 여포는 구강 연골조직 아래쪽 제 1, 2,3 도입새동맥 부근에 흩어져 존재하고, 출산 직후에는 13개 정도로 분화되어 있었다. 갑상선 여포의 수는 출산 직후(전장 6.3 mm)에 개체당 1.60.8개였으며, 치어기로 전환하는 30일째에는 17.02.1개, 50일째(전장 13.2 mm)에는 32.56.9개로 그 수가 매우 많아졌다. 갑상선

성선자극호르몬으로 자극된 난소로부터 회수된 사람의 성숙난자의 전핵형성과 초기발생에 정자의 운동성과 성숙도가 미치는 영향을 조사하였다. 세포질내정자주입 (ICSI)은 HEPES-buffer mTCM-199 배양액에서 실시하였다. 체내에서 성숙된 난구세포부착난자를 ICS에 의하여 사정된 운동성 정자 또는 비운동성 정자로 수정하였을 때 운동성 정자로 수정된 난자가 비운동성 정자로 수정된 난자보다 전핵형성율이 높았다 (79.8% vs 51.7% ; p<0.00

부화 후부터 평균전장 0.64 cm를 나타내는 부화 후 150일까지의 버들치, Rhynchocypris oxycephalus를 대상으로 초기생식소 발달과 성분화를 조사하였다. 시언생식세포는 평균전장 0.64cm 자어에서 뚜렷이 나타나\ulcorner. 평균전장 1.91 cm자어에서 시원생식세포는 복강으로돌출되었으며, 평균전장 2.29 cm 자어에서 시원생식세포는 감수분열 난모세포로 전환되었고, 난소로의 분화가 최초 확인되엇따. 평균전장 5.96 cm 자

Mammalian ovary consists of various growing stages of follicles. Ovarian follicular growth and differentiation, however, can be distinguished into recruitment, growth, selectiona nd ovulation. while only minute of the selected follicles ovulate their oocytes, all the rest follicles disappear by atresia. this atresia is an important event of which physiological mechanism must be resolved. The present study was carried out to investigate the effects of various doses of pregnant mare's serum gonadotropin (PMSG) on the oocyte quality, ovulation rate, and the early embryonic development in immature mice. Immature mice were administrated with 5, 20, or 40 IU PMSG. At every 12 hour up to 72 hour after treatment, body and ovary weights were measured. Oocytes were flushed from the oviducts under the dissecting microscope and observed under the inverted microscope. Late 2-cell embryos were collected from the mice which were superovulated by the same dosage of PMSG followed by 5 IU hCG 47 hours after PMSG-treatment. The percentage of abnormal oocytes was higher in 20 or 40 IU PMSG-treated animals than 5 IU PMSG-treated ones. Ovulation occured at 12 hours afger PMSG injection in all experimental groups. The percentage of retrieved abnormal oocytes increased in the 20 or 40 IU PMSG-treated goups but not in 5 IU PMSG-treated group. There was no significant difference in the mating rate among the groups [52.6% (10/19), 66.7% (10/15), 44.0% (11/25) : 5, 20, 40 IU group respectively] ; however, ther was a significant (p<0.01) increase of embryo retrieval rates in 5 and 20 IU-treated groups compared with that in 40 IU-treated group [89.2% (239-268), 85.5% (224/262), 40.0% (18/45)]. There was significant (p<0.01) increase of embryo development rates in 5 IU-treated group compared with that in 20 and 40 IU-treated group [231/239(96.7), 179/224(79.9), 77.8(14/18)]. In conclusion, higher doses of PMSG injection increased the occurrence of abnormal oocytes ovulation in immature mice. The most of oocytes collected from 5 or 20 IU-PMSG-treated group has fertilizabioity. But in mice injected iwth higher doses of PMSG, their oocytes exhibit less fertilizability and, even fertilized, all oocytes are not fully capable of development.