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Detection of Pathogenic Viruses in the Atmosphere during Asian Dust Events in Incheon City (인천지역에서 황사 기간 동안 대기 중의 바이러스 검출에 관한 연구)

  • Park, Jeong Woong;Lim, Young Hee;Kyung, Sun Young;An, Chang Hyeok;Lee, Sang Pyo;Jeong, Seong Hwan
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.3
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    • pp.279-285
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    • 2005
  • Background : Ambient particles during Asian dust events are usually less than $10{\mu}m$ in size, and known to be associated with the adverse effects on the general population. There is little evidence linking Asian dust to adverse effects on the airways. In 2002, the authors found that particulate matter during Asian dust events had an effect on the symptoms and pulmonary function of patients with bronchial asthma. An aggravating factor might be that of a viral infection, but this remains unclear. Conversely, it has been speculated that African dust may carry the virus responsible for foot and mouth disease. Asian dust events are also likely to be responsible for transporting viruses, some of which are pathogenic, and common in many environments. Therefore, in this study, air samples were screened for the presence of viruses. Methods : Air samples were collected 20 times each during Asian dust events and under non-dust conditions, for at least 6 hours per sample, using a high volume air sampler (Sibata Model HV500F), with an airflow rate of 500L/min, between April and August 2003, and between April and August 2004. The samples were then screened for the presence of targeted viruses (Influenza A, B, Hog cholera virus, and Aphthovirus) using a polymerase chain reaction method. Results : One Asian dust event occurred between April and August 2003, and 3 between April and August 2004, with a 24 hour average PM10 level of $148.0{\mu}g/m^3$. The 24 hour average PM10 level was $57{\mu}g/m^3$. There was a significant difference in the PM10 concentration between dusty and clear days. No viruses (Influenza virus, Aphthovirus, and Hog cholera virus) were identified in the air samples obtained during the dusty days. Conclusions : Although no virus was detected in this study, further studies will be needed to identify suspected viruses carried during Asian dust events, employing more appropriate virus detection conditions.

Effects of the Drainage Methods on Phenolic Compounds and Radical Scavenging Activity of Foxtail Millet and Proso Millet (배수방법이 조와 기장의 페놀성분 및 라디칼 소거활성에 미치는 영향)

  • Jung, Ki Yuol;Ko, Jee Yeon;Lee, Jae Saeng;Jeong, Mi Sun;Oh, In Seok;Woo, Koan Sik
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.59 no.3
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    • pp.282-292
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    • 2014
  • This study investigated the changes of antioxidant compounds and antioxidant activity of foxtail millet (FM) and proso millet (PM) by drainage methods in poorly drained sloping paddy field. The experimented soils in this study were very poorly drained (VPDP) and imperfectly drained paddy soil (IDP). Two drainage methods namely under pipe drainage (UPD) and open ditch (ODD) were installed within 1-m position at the lower edge of the upper paddy fields. The soil moisture contents of UPD and ODD on VPDP were $18.52{\pm}4.58$ and $19.01{\pm}4.25%$, and IDP were $14.87{\pm}4.82$ and $18.64{\pm}3.85%$, respectively. Generally, crop yields, proximate and minerals composition of FM and PM showed significant differences by drainage methods. The total polyphenol, flavonoid and tannin contents, and radical scavenging activity of the ethanolic extracts of FM and PM showed significant differences by drainage methods. The total polyphenol content of FM and PM by drainage methods was 1.69~2.30 and 1.18~1.35 mg GAE/g, total flavonoid content was 0.31~0.76 and 0.27~0.41 mg CE/g, and total tannin content was 0.36~0.54 and 0.21~0.28 mg TAE/g, respectively. The DPPH radical scavenging activity of FM and PM was 39.53~59.81 and 27.91~40.25 mg TE/100 g, and ABTS radical scavenging activity was 113.59~152.10 and 61.38~79.19 mg TE/100 g, respectively. The antioxidant compounds and radical scavenging activity of FM and PM by drainage methods were frequently affected soil water.

Effect of Band Spotty Fertilization on Yields and Nutrient Utilization of Garlic(Allium sativum L.) in Plastic Film Mulching Cultivation (마늘 재배시 양분이용율 및 수량에 미치는 국소시비 효과)

  • Yang, Chang-Hyu;Yoo, Chul-Hyun;Shin, Bok-woo;Kim, Jae-Duk;Kang, Seung-Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.39 no.6
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    • pp.380-385
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    • 2006
  • To establish law-put fertilization technique and increase of fertilization efficiency during cultivation of vinyl mulching for plant, the improvement of soil properties, nutrition efficiency and yields by band spotty fertilization(BSF) using band spotty applicator was carried out at garlic(Alltuiti sativum L.) field in Honam Agricultural Research Institute from 2001 to 2002 for 2 years. The value of pH and the content of total nitrogen, organic matter, exchangeable potassium and calcium of soil after experiment were increased but the content of available phosphate was decreased than soil before experiment. Uptake amounts of nitrogen fertilized by plants were more than in BSF plots($89{\sim}111kg\;ha^{-1}$) compared to in CF(conventional fertilization) Plot ($76kg\;ha^{-1}$) and nitrogen use efficiency were high in BSF plots(42.9~58.2%) compared to in CF plot(34.9%). Also Uptake amounts of potassium fertilized by plants were more than in BSF plots($34{\sim}58kg\;ha^{-1}$) compared to in CF plot($33kg\;ha^{-1}$) and potassium use efficiency were high in BSF plots(21.6~41.2%) compared to in CF plot(19.4%). Residual amount of nitrogen fertilized on soil were more than in BSF plots($38{\sim}54kg\;ha^{-1}$) compared to in CF plot($22kg\;ha^{-1}$) while loss amount of nitrogen fertilized on soil were less than in BSF plots($32{\sim}53kg\;ha^{-1}$) compared to in CF plot($120kg\;ha^{-1}$). Also Residual amount of potassium fertilized on soil were more than in 100% BSF plot($109kg\;ha^{-1}$) compared to in CF plot($72kg\;ha^{-1}$) while loss amount of nitrogen fertilized on soil were less than in BSF plots($14{\sim}38kg\;ha^{-1}$) compared to in CF plot($113kg\;ha^{-1}$). The BSF plots were increased plant height, leaf number, leaf sheath diameter, bulb diameter and height compared to CF plot. The total yields of garlic were more increased 14~19% because of high large bulb rate, commercial yields in 70, 100% BSF plots compared to in CF plot($102.9Mg\;ha^{-1}$). It was found that 70% band spotty fertilization was more effective as fertilization method to reduce both environmental pollution and chemical nitrogen fertilizer in plastic film mulching cultivation.

Comparison of Agrobacterium-mediated Transformation Efficiency in 43 Korean Wheat Cultivars (국내 밀 43개 품종에 대한 아그로박테리움 형질전환 효율성 검정)

  • Jae Yoon Kim;Geon Hee Lee;Ha Neul Lee;Do Yoon Hyun
    • Journal of Practical Agriculture & Fisheries Research
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    • v.25 no.4
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    • pp.138-147
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    • 2024
  • Agrobacterium-mediated transformation (AMT) is a method that allows for the stable integration of DNA fragments into the plant genome. Transgenic plants generated through AMT typically exhibit a lower copy number of the transgene compared to those induced by particle bombardment. Furthermore, AMT offers a straightforward and efficient approach for generating transgenic plants. While the transformation efficiency of wheat is comparatively lower than that of other monocot plants such as Rice (Oryza sativa L.) and Maize (Zea mays L.), the cultivars 'Bobwhites' and 'Fielder' are commonly employed for wheat transformation. To date, there have been no reported instances of successful development of transgenic plants using Korean wheat varieties through AMT. This study aims to assess the transformation efficiency of 43 Korean wheat cultivars using the GUS assay, with the goal of identifying suitable Korean wheat cultivars for AMT. The pCAMBIA1301 vector, carrying the β-glucuronidase (GUS) gene, was incorporated into Agrobacterium strain EH105. Following the inoculation of Agrobacterium into immature embryos, GUS assays were conducted 'Saeol', 'Jopum', and 'Jonong' showed 100% (the number of embryos showing GUS spots/the number of embryos used for AMT) among 43 cultivars. In addition, cultivars with more than 70% were 'Saekeumgang', 'Jojung', 'Tapdong', 'Anbaek', 'Dabun', 'Sugang', 'Keumgang', 'Jeokjung', 'Seodun', 'Joeun', 'Dajung', and 'Baekjung'. It seems that the 15 cultivars above showed the possibility of using AMT. On the other hand, 'Yeonbaek', 'Goso', 'Baekgang', and 'Johan' showed less than 20% and GUS spots were not observed in 'Gru', 'Gobun', 'Milseong', and 'Shinmichal-1'. This study explores transient GUS expression in Korean wheat cultivars seven days after AMT. The observed initial high efficiency of transient transformation suggests the potential for subsequent stable transformation efficiency. Korean wheat cultivars demonstrating elevated transient transformation efficiency could serve as promising candidates for the development of stable transgenic wheat.

Prophylactic and therapeutic studies on intestinal giant-cystic disease of the Israel carp caused by Thelophanellus kitauei II. Effects of physical and chemical factors on T. kitauei spores in vitro (향어의 장포자충(Thelohanellus kitauei)증의 예방 및 치료에 관한 기초적 연구 II. 물리화학적 요인이 장포자충 포자에 미치는 영향)

  • Lee, Jae-Gu;Kim, Jong-O;Park, Bae-Geun
    • Parasites, Hosts and Diseases
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    • v.28 no.4
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    • pp.241-252
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    • 1990
  • In a basic attempt to develop the prophylactic and therapeutic measures on intestinal giantcystic disease of the Israel carp, C), prinks carpio nudum, the effects of physical and chemical factors on viability or survival of the spores of Thelchcnellus kiteuei were checked in vitro by means of extrusion test on the polar filament. When the fresh spores suspended with 0.45% and 0.9% scdium chloride solution and distilled water were laid at $5^{\circ}C$ and $28^{\circ}C$ for short terms, the extrusion rates increased until the 3rd day, meanwhile when son;e of them were suspended with Tyrode's solution at $-70^{\circ}C$ the rates increased gradually until the 8th day. Viabilities of the spores suspended with 0.9% saline and added antibiotics to the suspension at $5^{\circ}C$ for long terms lasted for 997 days and 1, 256 days (presumed values) at maximum, respectively. The spores suspended with distilled water at $28^{\circ}C$ for long terms survived 152.4 days, but the spores suspended with Tyrode's solution at $-70^{\circ}C$ for long terms showed almost the same viable pattern as early freezing stages up to 780 days. The spores suspended with Tyrode's solution, frozen at $-70^{\circ}C$ and thawed at $5^{\circ}C$, showed the highest rate of extrusion of the polar filament. In the case of frozen spores, the extrusion rates during heating tend to become higher in accordance with the increase of frozen period, and the critical points of 180 day-frozen spores to be killed were generally 78.5 hr. at $60^{\circ}C$, 23.4 hr. at $70^{\circ}C$, 189.1 min. at $80^{\circ}C$ or 10.5 min. at $90^{\circ}C$. The longer the spores were frozen, the more time was needed for the death of spores after thawing; 20 days-17.4 days, 100 days-33.2 days, and 400 days-37.8 days. The longer the spores were frozen, the more time was needed for the death of spores at a conventional when they were dried air drying condition, 540 days-23.5 days, 160 days-21.0 days, and 20 days-14.4 days. On the other hand, the longer the spores were frozen, the more spores were dead rapidly when they were irradiated with 10W UV-ray; 100 days-26.0 hr, 300 days-21.9 hr, and 540 days-13.9 hr. The time needed for killing 200 days-frozen spores by various disinfectants at 1, 000 ppd was 5.2 min. by calcium oxide, 10.4 min. by potassium permanganate, 27.8 min. by malachite green and 14.3 hr. by formalin. Transient inhibitory effects of the extrusion of the polar filament were observed by various antiprotozoal and antifungal agents in the descending order of ketoconazole. metronidasole and dapsone. The above results presume that full drying, followed by spraying CaO and maintaining sunny condition for a few days on the concrete bottoms of knish farm may be an effective method for the prevention of intestinal giant.cystic disease.

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Estimation of Internal Motion for Quantitative Improvement of Lung Tumor in Small Animal (소동물 폐종양의 정량적 개선을 위한 내부 움직임 평가)

  • Yu, Jung-Woo;Woo, Sang-Keun;Lee, Yong-Jin;Kim, Kyeong-Min;Kim, Jin-Su;Lee, Kyo-Chul;Park, Sang-Jun;Yu, Ran-Ji;Kang, Joo-Hyun;Ji, Young-Hoon;Chung, Yong-Hyun;Kim, Byung-Il;Lim, Sang-Moo
    • Progress in Medical Physics
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    • v.22 no.3
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    • pp.140-147
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    • 2011
  • The purpose of this study was to estimate internal motion using molecular sieve for quantitative improvement of lung tumor and to localize lung tumor in the small animal PET image by evaluated data. Internal motion has been demonstrated in small animal lung region by molecular sieve contained radioactive substance. Molecular sieve for internal lung motion target was contained approximately 37 kBq Cu-64. The small animal PET images were obtained from Siemens Inveon scanner using external trigger system (BioVet). SD-Rat PET images were obtained at 60 min post injection of FDG 37 MBq/0.2 mL via tail vein for 20 min. Each line of response in the list-mode data was converted to sinogram gated frames (2~16 bin) by trigger signal obtained from BioVet. The sinogram data was reconstructed using OSEM 2D with 4 iterations. PET images were evaluated with count, SNR, FWHM from ROI drawn in the target region for quantitative tumor analysis. The size of molecular sieve motion target was $1.59{\times}2.50mm$. The reference motion target FWHM of vertical and horizontal was 2.91 mm and 1.43 mm, respectively. The vertical FWHM of static, 4 bin and 8 bin was 3.90 mm, 3.74 mm, and 3.16 mm, respectively. The horizontal FWHM of static, 4 bin and 8 bin was 2.21 mm, 2.06 mm, and 1.60 mm, respectively. Count of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.10, 4.83, 5.59, 5.38, and 5.31, respectively. The SNR of static, 4 bin, 8 bin, 12 bin and 16 bin was 4.18, 4.05, 4.22, 3.89, and 3.58, respectively. The FWHM were improved in accordance with gate number increase. The count and SNR were not proportionately improve with gate number, but shown the highest value in specific bin number. We measured the optimal gate number what minimize the SNR loss and gain improved count when imaging lung tumor in small animal. The internal motion estimation provide localized tumor image and will be a useful method for organ motion prediction modeling without external motion monitoring system.

Relationship between Vaginal Cytology and Reproductive Hormone during the Estrous Cycle and Optimal Mating Time in Beagle Dogs (비글개에서 발정 주기 및 교배 적기 동안 질세포상과 번식 호르몬의 관계)

  • Lee K.C.;Kang H.G.;Cheun H.M.;Kim I.H.
    • Journal of Embryo Transfer
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    • v.21 no.2
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    • pp.109-119
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    • 2006
  • This study was conducted to examine relationship between vaginal cytology and reproductive hormones during the estrous cycle and to provide basic data to estimate for ovulation time and optimal mating time in 6 beagle dogs The duration of proestrus, estrus and diestrus were $8.5{\pm}1.4,\;10.0{\pm}1.4\;and\;54.0{\pm}2.8$ days at pregnant respectively, and $7.9{\pm}2.1,\;9.5{\pm}0.7\;and\;62.0{\pm}11.3$ days at non-pregnant respectively. The duration of interestrous intervals were $246.2{\pm}24.5$ days at pregnancy, and $175.3{\pm}34.5$ days at non-pregnancy. The duration of interestrous intervals at pregnancy was longer than that of non-pregnancy. A characteristic features of vaginal cytology during the estrous cycle were the high proportion of superficial cell, anuclear cell and erythrocyte in proestrus and estrus, parabasal cell, small intermediate cell and leukocyte in diestrus, and parabasal cell and small intermediate cell in anestrus, respectively. Cornification index (CI) in proestrus and estrus were significantly higher than that of CI in diestrus and anestrus. Plasma progesterone concentration was below 1.0 ng/ml at the first day of vulval bleeding at pregnancy and non-pregnancy, and then it was above 2.0 ng/ml at Day -2 in all bitches. When plasma progesterone concentration was first increased above 4.0 ng/ml, it was the second day after the first day of male acceptance. Plasma progesterone concentration showed above 40 ng/ml on Day $20{\sim}22$ in all bitches, and then it was gradually decreased until Day 35. Plasma progesterone concentration at pregnancy was higher than that of non-pregnancy from Day 35 to Day 63. Plasma estradiol-$17\;{\beta}$ concentration was above 9.0 pg/ml at the first day of vulval bleeding, and it showed 26.4 pg/ml on Day -2. When it was timed from the first day of male acceptance (Day 0), plasma estradiol-$17{\beta}$ concentration showed a peak on Day 0 and plasma progesterone concentration was first increased above 4.0 ng/ml on Day 2 which was the third day after plasma estradiol-$17{\beta}$ peak. CI was first increased above 80 and 90% on Day -1 and Day 1, respectively. CI was maintained above 80% from Day -1 to Day 8 (10 days) and above 90% from Day 1 to Day 6 (6 days), respectively. CI was maintained above 80% from Day 0 to Day 8 (9 days) and above 90% from Day 1 to Day 6 (6 days), respectively. Plasma progesterone concentration was first increased above 4.0 ng/ml on the second day after the day which CI was first increased above 90%. In conclusion, beagle bitches ovulated on the second day after the day which CI was first increased above 90% and on the day which plasma progesterone concentration was first increased 4.0 ng/ml, and it was estimated that the optimal mating time was the day which the second day after CI was first increased above 90% and plasma concentration was between $2{\sim}25ng/ml$. The measurement of plasma progesterone was used to determine of and accurate ovulation time and the optimal mating time, but vaginal cytology is low-priced and simple method to estimate estrous cycle, optimal mating time and ovulation time.

Effect of Cooling Timing in the Root Zone on Substrate Temperature and Physiological Response of Sweet Pepper in Summer Cultivation (여름 파프리카 수경재배에서 근권 냉방 시간이 근권 온도와 생리적 반응에 미치는 영향)

  • Choi, Ki Young;Ko, Ji Yeon;Yoo, Hyung Joo;Choi, Eun Young;Rhee, Han Cheol;Lee, Yong-Beom
    • Horticultural Science & Technology
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    • v.32 no.1
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    • pp.53-59
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    • 2014
  • This study aimed to determine an appropriate cooling timing in the root zone for lowering substrate temperature and its effect on physiological response of sweet pepper (Capsicum annum L. 'Orange glory') grown on coir substrate in summer, from the July 16 to October 15, 2012. Daily temperature of substrate, root activity, leaf water potential, first flowering date, and the number of fruits were measured by circulating cool water through a XL pipe in the root zone during either all day (all-day) or only night time (5 p.m. to 3 a.m.; night) from the July 23 to September 23, 2012. For comparison, no cooling (control) was also applied. Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), daily average temperatures in substrates were $25.6^{\circ}C$, $26.1^{\circ}C$, and $29.1^{\circ}C$ for the all-day and night treatment, and control respectively. About 1.8 to $5^{\circ}C$ lower substrate temperature was observed in both treatments compared to that of control. In sunny day ($600-700 W{\cdot}m^{-2}{\cdot}s^{-1}$), the highest temperature of substrate was measured between 4 p.m. and 5 p.m. under both the all-day and night treatments, whereas it was measured between 7 p.m. and 8 p.m. under the control. Substrate temperatures during the day (6 a.m. to 8 p.m.) and night (8 p.m. to 6 a.m.) differed depending on the treatments. During the day and night, averaged substrate temperature was lower about $3.3^{\circ}C$ and $4.0^{\circ}C$ for the all-day, and $2.1^{\circ}C$ and $3.4^{\circ}C$ for the night treatment, compared to that of control. In the all-day and night treatment, the TD [TD = temperature of (control)] was greater in bottom than that of other regions of the substrate. Between the day and night, no different TD values were observed under the all-day treatment, whereas under the night treatment there was difference with the greatest degree in the bottom of the substrate. During the hot temperature period, total numbers of days when substrate temperature was over $25^{\circ}C$ were 40, 23 and 27 days for the control, all-day, and night treatment, respectively, and the effect of lowering substrate temperature was therefore 42.5% and 32.5% for the all-day and night treatment, respectively, compared to that for the control. Root activity and leaf water potential of plants grown under the all-day treatment were significantly higher than those under the night treatment. The first flowering date in the all-day treatment was similar to that in the night treatment, but 4-5 day faster than in the control. Also, the number of fruits in both treatments was significantly higher than that in the control. However, there was no effect of root zone cooling on eliminating delay in fruiting caused by excessively higher air temperature (> $30^{\circ}C$), although the substrate temperature was reduced $18^{\circ}C$ to $5^{\circ}C$. These results suggest that the method of cooling root zone temperature need to be incorporated into the lowering growing temperature for growth and fruit set of health paprika.

Protoplast Fusion of Nicotiana glauca and Solanum tuberosum Using Selectable Marker Genes (표식유전자를 이용한 담배와 감자의 원형질체 융합)

  • Park, Tae-Eun;Chung, Hae-Joun
    • The Journal of Natural Sciences
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    • v.4
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    • pp.103-142
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    • 1991
  • These studies were carried out to select somatic hybrid using selectable marker genes of Nicotiana glauca transformed by NPTII gene and Solanum tuberosum transformed by T- DNA, and to study characteristics of transformant. The results are summarized as follows. 1. Crown gall tumors and hairy roots were formed on potato tuber disc infected by A. tumefaciens Ach5 and A. rhizogenes ATCC15834. These tumors and roots could be grown on the phytohormone free media. 2. Callus formation from hairy root was prompted on the medium containing 2, 4 D 2mg/I with casein hydrolysate lg/l. 3. The survival ratio of crown gall tumor callus derived from potato increased on the medium containing the activated charcoal 0. 5-2. 0mg/I because of the preventions on the other hand, hairy roots were necrosis on the same medium. 4. Callus derived from hairy root were excellently grown for a short time by suspension culture on liquid medium containing 2, 4-D 2mg/I and casein hydrolysate lg/l. 5. The binary vector pGA643 was mobilized from E. coli MC1000 into wild type Agrobacteriurn tumefaciens Ach5, A. tumefaciens $A_4T$ and disarmed A. tuniefaciens LBA4404 using a triparental mating method with E. ccli HB1O1/pRK2013. Transconjugants were obtained on the minimal media containing tetracycline and kanamycin. pGA643 vectors were confirmed by electrophoresis on 0.7% agarose gel. 6. Kanamycin resistant calli were selected on the media supplemented with 2, 4-D 0.5mg/1 and kanamycin $100\mug$/ml after co- cultivating with tobacco stem explants and A. tumefaciens LBA4404/pGA643, and selected calli propagated on the same medium. 7. The multiple shoots were regenerated from kanamycin resistant calli on the MS medium containing BA 2mg/l. 8. Leaf segments of transformed shoot were able to grow vigorusly on the medium supplemented with high concentration of kanamycin $1000\mug$/ml. 9. Kanamycin resistant shoots were rooting and elongated on medium containing kanamycin $100\mug$/ml, but normal shoot were not. 10. For the production of protoplast from potato calli transformed by T-DNA and mesophyll tissue transformed by NPTII gene, the former was isolated in the enzyme mixture of 2.0% celluase Onozuka R-10, 1.0% dricelase, 1.0% macerozyme. and 0.5M mannitol, the latter was isolated in the enzyme mixture 1.0% Celluase Onozuka R-10, 0.3% macerozyme, and 0.7M mannitol. 11. The optimal concentrationn of mannitol in the enzyme mixture for high protoplast yield was 0.8M at both transformed tobacco mesophyll and potato callus. The viabilities of protoplast were shown above 90%, respectively. 12. Both tobacco mesophyll and potato callus protoplasts were fused by using PEG solution. Cell walls were regenerated on hormone free media supplemented with kanamycin after 5 days, and colonies were observed after 4 weeks culture.

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Primary Production and Nitrogen Regeneration by Macrozooplankton in the Kyunggi Bay, Yellow Sea (서해 경기만의 기초생산력 및 질소계 영양염의 재생산에 관한 연구)

  • Chung, Kyung Ho;Park, Yong Chul
    • 한국해양학회지
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    • v.23 no.4
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    • pp.194-206
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    • 1989
  • Seasonal variations of nutrients (ammonium, nitrite, nitrate, phosphate and silicate), primary productivity and ammonium regeneration rate of macrozooplankton were investigate to understand the relationship between nitrogen recycling and nitrogen requirement by phytoplankton from Feburuary 1986 to November 1987 in the Kyunggi Bay, shallow estuarine water of Yellow Sea. In general, nutrients increased during the winter and depleted during the spring and the early summer except temporally sharp increase after flood in September. Ammonium was prevalently generally found in high concentration throughout the study area and it occasionally raised N/P ratio in the range of 30 to 70 as in the freshwater environment. Daily net primary productivity ranged from 30.3 to 3580.0 mgC/$m^2$/d with an average of 883.9 mgC/$m^2$/d. Annual primary productivity was determined to be 320.0 gC/$m^2$/yr. Carbon assimilation number ranged from 2.9 to 19.4 mgC/mg chl-a/h which increased in the summer and decreased in the winter. Nitrogen requirement by phytoplankton ranged from 0.4 to 45.0 mg at-N/$m^2$/d and turnover time of inorganic nitrogen ranged from 2.4 in the late summer to 122.7 days in the winter. Nitrogen regeneration rate of mixed macrozooplankton determined by bottle incubation method ranged from 0.02 to 1.34 mg at-N $m^2$/d and it could contribute from 2.8 to 38.7% with an annual average of 14.9% of total nitrogen requirement by phytoplankton in this shallow estuarine environment.

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