• Clinical and Experimental Reproductive Medicine
• /
• 제26권3호
• /
• pp.407-417
• /
• 1999

Objective: Mammalian follicle cells are the most important somatic cells which help oocytes grow, mature and ovulate and thus are believed to provide oocytes with various functional and structural components. In the present study we have examined whether cumulus or granulosa cells might playa role in establishing the plasma membrane structure of mouse oocytes during meiotic maturation. Design: In particular the differential resistances of mouse oocytes against chymotrypsin treatment were examined following culture with or without cumulus or granulosa cells, or in these cell-conditioned media. Results: When mouse denuded oocytes, freed from their surrounding cumulus cells, were cultured in vitro for $17{\sim}18hr$ and then treated with 1% chymotrypsin, half of the oocytes underwent degeneration within 37.5 min ($t_{50}=37.5{\pm}7.5min$) after the treatment. In contrast cumulus-enclosed oocytes showed $t_{50}=207.0$. Similarly, when oocytes were co-cultured with cumulus cells which were not associated with the oocytes but present in the same medium, the $t_{50}$ of co-cultured oocytes was $177.5{\pm}13.1min$. Furthermore, when oocytes were cultured in the cumulus cell-conditioned medium, $t_{50}$ of these oocytes was $190.0{\pm}10.8min$ whereas $t_{50}$ of the oocytes cultured in M16 alone was $25.5{\pm}2.9min$. Granulosa cell-conditioned medium also increased the resistance of oocytes against chymotrypsin treatment such that $t_{50}$ of oocytes cultured in granulosa cell-conditioned medium was $152.5{\pm}19.0min$ while that of oocytes cultured in M16 alone was $70.0{\pm}8.2min$. To see what molecular components of follicle cell-conditioned medium are involved in the above effects, the granulosa cell-conditioned medium was separated into two fractions by using Microcon-10 membrane filter having a 10 kDa cut-off range. When denuded oocytes were cultured in medium containing the retentate, $t_{50}$ of the oocytes was $70.0{\pm}10.5min$. In contrast, $t_{50}$ of the denuded oocytes cultured in medium containing the filtrate was $142.0{\pm}26.5min$. $T_{50}$ of denuded oocytes cultured in medium containing both retentate and filtrate was $188.0{\pm}13.6min$. However, $t_{50}$ of denuded oocytes cultured in M16 alone was $70.0{\pm}11.0min$ and that of oocytes cultured in whole granulosa cell-conditioned medium was $156.0{\pm}27.9min$. When surface membrane proteins of oocytes were electrophoretically analyzed, no difference was found between the protein profiles of oocytes cultured in M16 alone and of those cultured in the filtrate. Conclusions: Based upon these results, it is concluded that mouse follicle cells secrete a factor(s) which enhance the resistance of mouse oocytes against a proteolytic enzyme treatment. The factor appears to be a small molecules having a molecular weight less than 10 kDa.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1991년도 하계학술대회 논문집
• /
• pp.300-303
• /
• 1991

Sulphur-hexafluoride has extensively been used as an insulating gas of electric power equipment in substation for its high dielectric strength, non-toixity and non-flammable properties. But it is very expensive and is liquidizable under the condition of low temperature and high pressure. And it is very sensible to the locally high electric field strength. To resolve these problems, we studied 50% FOV and V-t characteristics of $SF_6-N_2$ mixtures under positive and negative lightning impulses using a 25mm rod-plane gap. 50% FOV of $SF_6-N_2$ 50% mixture was about 85% of pure $SF_6$ and it was known that $SF_6-N_2$ mixtures can be used as an economic substitution insulating gas for $SF_6$.

• 한국조명전기설비학회지:조명전기설비
• /
• 제5권2호
• /
• pp.49-57
• /
• 1991

광원의 상관색온도와 연색성을 측정할 수 있는 간단한 시스템을 개발하였다. 전원전압과 전원주파수 변동시 백열전구와 각종 형광등의 색온도 및 연색성이 변화하는 경향을 측정하였다. 측정 결과, 통상 발생될 수 있는 전압변동의 범위 내에서 백열전구와 형광등의 색온도는 비교적 많이 변화하나, 연색평가수는 거의 변화하지 않는 것을 알 수 있었다. 또한 50kHz 까지의 주파수 변동 범위에서 형광등의 색온도와 연색성은 변화가 적었으나. 50kHz 이상으로 되면 많은 변화가 있을 것으로 예측된다.

• 상하수도학회지
• /
• 제21권5호
• /
• pp.589-599
• /
• 2007

This study was conducted to investigated the removal efficiency of BOD and nutrient for the treatment of low strength municipal wastewater by a biological nutrient removal system. In this experiment, the effect of operating parameter including HRT of 7.0hr, BOD/TN ratios of 2.62~4.08, internal recycle of 50~300%, and return sludge of 50~100%, were studied during winter season. Efficiencies of organic matter and T-P removal and denitrification were not significantly affected by the change of temperature in winter season. However, the specific nitrification rate and nitrification efficiency decreased at low temperature. Besides, denitrification efficiencies increased with increasing BOD/TN ratios. It was also found that the internal recycle and return sludge ratio below 50% is required for the effective denitrification of low strength municipal wastewater. With operating mode 4 of the optimum, the effluent BOD, T-N and T-P concentration were obtained to average 5.8, 14.6, and 0.84 mg/L, respectively. The temperature-activity coefficient (${\theta}$) of specific nitrification rate, specific denitrification rate and specific phosphorus uptake rate were obtained 1.044, 1.017, 1.028, respectively.

• 물과 미래
• /
• 제6권2호
• /
• pp.30-37
• /
• 1973

The coefficient of the current meter generally determined by the maker Its coefficient is subject to being changed with time. Therefore the coefficient of the current meter has to be checked up before it is ready to be used Such an inspection is termed a current meter rating The current meter equipped an electronic apparatus and all the others are to be rated in a rating flume. The price current meter which is most widely used for measuring flow velocities ranging between 0.3m/sec and 3.5m/sec has been used in this study. The length of the flume and the optimum range of the rating in the cross section are determined in the range of 20∼120cm deep, 50∼160cm wide of the flume. In this study, the 23 different kinds of the current meter rating enabled us to determine the constants a and b of the following equation. V=an+b(m/sec) where, n is number of revolution per second(n=N/T) V is velocity(v=D/T) The above constant can be determined by the least squares method and plotting, using the velocity(V=D/T) and the number of revolution per second(n=N/T) obtained from the running distance(D), time(T), the number of revolutin(N), and the running number(m). From the experiments the following conclusions are drawn: 1) The rating flume is large enough if the flume is 110∼120cm deep, and 40∼50m long. 2) The optimum depth for rating of a current meter is in the range of h=40∼50cm.

• 한국동물생명공학회지
• /
• 제37권3호
• /
• pp.169-175
• /
• 2022

Bovine mammary epithelial (MAC-T) cells are commonly used to study mammary gland development and mastitis. Lipopolysaccharide is a major bacterial cell membrane component that can induce inflammation. Autophagy is an important regulatory mechanism participating in the elimination of invading pathogens. In this study, we evaluated the mechanism underlying bacterial mastitis and mammary cell death following lipopolysaccharide treatment. After 24 h of 50 ㎍/mL lipopolysaccharide treatment, a significant decrease in the proliferation rate of MAC-T cells was observed. However, no changes were observed upon treatment of MAC-T cells with 10 ㎍/mL of lipopolysaccharide for up to 48 h. Thus, upon lipopolysaccharide treatment, MAC-T cells exhibit dose-dependent effects of growth inhibition at 10 ㎍/mL and death at 50 ㎍/mL. Treatment of MAC-T cells with 50 ㎍/mL lipopolysaccharide also induced the expression of autophagy-related genes ATG3, ATG5, ATG10, ATG12, MAP1LC3B, GABARAP-L2, and BECN1. The autophagy-related LC3A/B protein was also expressed in a dose-dependent manner upon lipopolysaccharide treatment. Based on these results, we suggest that a high dose of bacterial infection induces mammary epithelial cell death related to autophagy signals.

• 원예과학기술지
• /
• 제19권4호
• /
• pp.511-514
• /
• 2001

일반적으로 종자를 pelleting하면 발아율이나 발아세가 나종자보다 저하되어 실용화하는데 다소 걸림돌이 되고 있다. 본 연구는 시판되는 춘파용 당근 4품종을 공시하여 pelleting 전 solid matrix priming(SMP), osmo priming, $GA_3$의 처리를 하여 4품종 모두 pelleting보다 발아율이 10-50% 향상되었으며, $T_{50}$가 1.9-4.6일 단축되었다. 포장에서의 입모율은 SMP+pelleting 종자가 pelleting 시키지 않은 종자보다 높았고, $T_{50}$이 단축되었지만 큰 차이는 없었다. 이런 불균일한 묘출현은 포장의 불량한 온도와 수분환경 때문인 것으로 생각되며 수분과 pelleting 종자와의 관계에 대한 추가 시험을 수행할 계획이다.

• Current Research on Agriculture and Life Sciences
• /
• 제29권
• /
• pp.1-10
• /
• 2011

This study was conducted to determine the agronomic characteristics of low amylose lines which were derived from induced mutants by T-DNA insertion. The agronomic and physicochemical properties of the low amylose mutants were analyzed and compared with a donor cultivar 'Dongjin' and a low amylose cultivar 'Baekjinju'. The heading date of the low amylose mutants was similar to the donor cultivar 'Dongjin' and yield index of the mutants was 78~92% compared with 'Dongjin'. The amylose content of four mutants in brown rice was ranged from 16.1 to 16.7%. Among low amylose mutants, 'P50-4-4-5' was lower 3.6%(13.3%) than those of 'Dongjin'(16.9%) in amylose content of milled rice. The grain length of 'P50-4-4-5' was similar to the donor cultivar, however, thousand grain weight(18.9g) was lighter than those of 'Dongjin'. The score of alkali digestion in brown rice of 'P50-4-4-5'(5.5) was lower than that of 'Dongjin'(6.8) and similar to 'Baekjinju'(5.8). The gel consistency of 'P50-4-4-5'(84mm) in milled rice exhibited that was longer than 'Dongjin'(76mm) and 'Baekjinju'(81mm). The result of eating quality showed that 'P50-4-4-5'(78.8) was higher than those of 'Dongjin'(60.3) and 'Baekjinju'(67.2). Thus our data suggest that 'P50-4-4-5' will facilitate the development of a new cultivar with low amylose rice.

• 한국어류학회지
• /
• 제17권3호
• /
• pp.159-166
• /
• 2005

한국산 꾸구리속 (Gobiobotia) 어류인 꾸구리 (G. macrocephala), 돌상어 (G. brevibarba) 및 흰수마자 (G. nakdongensis)의 핵형을 조사하였다. 연구 결과, 각각 25쌍의 배수체 염색체가 관찰되었 다. 핵형은 꾸구리가 2n = 50 (9M+7SM+9ST), NF = 100, 염색체의 길이는 $3.3{\sim}7.5{\mu}m$ 크기였으며, 돌상어는 2n = 50 (10M+7SM+4ST+4T), NF = 92, 염색체의 길이는 $2.7{\sim}6.3{\mu}m$의 크기였고, 흰수마자는 2n = 50 (5M+9SM+9ST+2T), NF = 96, 염색체의 길이는 $3.5{\sim}7.3{\mu}m$였다. 본 연구결과 꾸구리와 흰수마자의 핵형은 처음으로 보고되었다.

• Journal of Applied Biological Chemistry
• /
• 제49권4호
• /
• pp.171-175
• /
• 2006

Chitin compost and broth were used to suppress club root. Individual cabbage seedlings were transplanted into pots(3500 ml) containing a mixture of 3% chitin compost and 50 ml of chitin broth (T1) or the same quantity control compost and control compost broth(T2). The media in each pot was then infected with Plasmodiophora brassicae. Samples were taken at 6, 7 and 8 weeks after transplanting. The population of chitinase producing bacteria in T1 was consistently larger than that observed in T2. Chitinase activity in the T1 rhizosphere was two-fold greater than that of T2 at each time point observed. Shoot dry weight, leaf number and leaf area in T1 were enhanced 20%, 10% and 12% relative to those seen in T2, respectively. The disease index and root mortality at 8 weeks after transplanting were reduced by 50% and 25% in T1 compared to T2, respectively. Results presented in this study are strongly indicative that chitin compost and broth suppress clubroot in Chinese cabbage.