• 한국주조공학회지
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• 제40권2호
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• pp.7-15
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• 2020

The high-temperature stability of Mg-8.0Zn-1.6Y (wt.%) alloys upon the addition of Ca has been investigated by characterizing the ignition temperature, microstructure, tensile and creep properties. The ignition temperature increases with an increase in the Ca content, indicating that an addition of Ca enhances the ignition resistance of the Mg-Zn-Y alloy. The as-cast microstructures of all tested alloys mainly consisted of the dendritic α-Mg matrix and I-phase (Mg₃Zn₆Y) at the grain boundaries. In the Ca-added Mg-8.0Zn-1.6Y alloys, the Ca₂Mg₆Zn₃ phase forms, with this phase fraction increasing with an increase in the Ca contents. However, a high volume fraction of the Ca₂Mg₆Zn₃ phase rather deteriorates the mechanical properties. Therefore, a moderate amount of Ca element in Mg-8.0Zn-1.6Y alloys is effective for improving the tensile and creep properties of the Mg-Zn-Y alloy. The Mg-8.0Zn-1.6Y-0.3Ca alloy exhibits the highest tensile strength and the lowest creep strain among the alloys investigated in the present study. The creep resistance of Mg-Zn-Y-Ca alloys depends on the selection of the secondary solidification phase; i.e., when Ca₂Mg₆Zn₃ forms in an alloy containing a high level of Ca, the creep resistance deteriorates because Ca₂Mg₆Zn₃ is less stable than the I-phase at a high temperature.

• Journal of Plant Biotechnology
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• 제45권3호
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• pp.155-170
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• 2018

본 논문은 현재까지 개발된 유전자편집 기술들의 작용기작 및 장 단점 등을 비교하고 이들 기술로 개발된 유전자편집(site-directed mutagenesis, SDN)작물들의 안전성 평가를 위한 분류 기준 등을 살펴보았다. 또한 2016년부터 2018년 5월 현재까지 발표된 유전자편집 식물 개발과 관련된 논문들을 조사하여 ZFN, TALENS, CRISPR기술별 발표 논문 추세를 조사한 결과 CRISPR기술을 적용한 연구건수가 절대적으로 많았다. 또한 애기장대와 벼를 대상으로 수행한 연구건수가 가장 많았으며, 담배와 토마토, 밀, 옥수수 등이 그 뒤를 이었다. 하지만 발표건수는 아직 1~2건에 해당하지만 대상 식물들은 주곡작물을 포함하여 화훼, 채소, 과수 등으로 다양하게 그 응용 범위가 확대되고 있는 것으로 조사되었다. 특히 실용화 또는 향후 상업화를 목표로 한 연구건수도 해마다 증가하는 추세에 있으며 그 응용 범위도 유용단백질 또는 물질의 대량생산을 위한 대사공학 연구와 바이러스, 세균, 곰팡이 등에 대한 병저항성 작물의 개발, 가뭄 등의 무생물적 환경스트레스 저항성 작물, 수량이 증대된 작물 등의 개발에 집중되었다. 이 외에도 단위결실 토마토, 웅성불임성 이용 hybrid벼, 탈립 저항성 증진 등으로 응용 범위가 점점 다양화되어 가고 있음을 알 수 있었다. 또한 미국 농무성의 동 식물 검역소에서 허가를 득한 CRISPR유전자편집 작물의 건수도 해마다 증가하여 조만간 이들이 국제 종자시장에 출시될 것으로 전망된다.

• 한국작물학회지
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• 제50권spc1호
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• pp.62-68
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• 2005

호남평야지에서 고품질 쌀 생산을 위한 품종별 적정 수확시기를 검토하기 위하여 $2002\~2004$년에 평야지인 익산에서 조생종인 삼천벼, 중생종인 화성벼, 중만생종인 남평벼를 공시하여 시험을 수행하였는데, 그 결과를 요약하면 다음과 같다. 1. 등숙비율은 삼천벼는 출수 후 $50\~55$일, 화성벼 $55\~60$일, 남평벼 60일 이후수확에서 높았고 현미천립중은 삼천벼는 출수 후 $50\~55$일, 화성벼 55일, 남평벼 $55\~60$일 수확에서 무거웠다. 2. 쌀 수량은 삼천벼는 출수 후 $45\~50$일, 화성벼 $50\~55$일, 남평벼 $55\~60$일 수확에서 많았다. 3. 완전미 수량은 삼천벼는 출수 후 45일, 화성벼 50일, 남평벼 $55\~60$일 수확에서 많았다. 4. 따라서 호남평야지에서 완전미 수량, 쌀 품위, 단백질 함량, Toyo 식미치 등을 고려한 수확적기는 삼천벼는 출수 후 52일(적산온도 $1,213^{\circ}C$), 화성벼는 출수 후 56일$(1,221^{\circ}C)$, 남평벼는 출수 후 60일$(1,207^{\circ}C)$경으로 생각된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.237-237
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• 2017

Rice is highly sensitive to salt stress especially in its early growth stage, which thus is one of the major constraints in rice production. In rice plants, salt sensitivity is associated with the accumulation of $Na^+$ in the shoots, especially in the photosynthetic tissues. High salt concentrations in soil cause high $Na^+$ and $Cl^-$ transport to the shoot and preferential accumulation of those ions in older leaves, which decreases $K^+$ in the shoot, photosynthetic activity and grain yield. Salt exclusion capacity at the leaf sheath is therefore considered to be one of the main mechanisms of salt tolerance. In addition, it is suspected that the lamina joint might be involved in the salt transport from leaf sheath to leaf blade. This research aims to determine if leaf sheaths of rice exclude a large amount of $Na^+$ only or other ions such as $K^+$, $Ca^{2+}$, $Mg^{2+}$, and $Cl^-$ as well, to identify tissues in the leaf sheath, which accumulate $Na^+$, and to examine if the lamina joint is involved in the salt exclusion by the leaf sheath. The rice seedlings of salt tolerant genotype FL478 and salt sensitive genotype IR29 were independently treated with NaCl, KCl, $MgCl_2$ and $CaCl_2$, and Taichung 65 and its near-isogenic liguleless line (T65lg) were treated with NaCl. Then, the content of $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, and $Cl^-$ ions and their specific location were determined using Atomic Absorption Spectrometer, Ion Chromatograph, and Energy Dispersive X-ray Spectroscopy. Results showed that leaf sheaths of FL478 and IR29 accumulated a large amount of $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, and $Cl^-$ ons, and thus excluded them from leaf blades when treated with high concentration of each salt. When treated with NaCl, the highest $Na^+$ concentration was found in the basal part of leaf sheaths of both cultivars. Moreover, energy-dispersive X-ray spectroscopy revealed that the central parenchyma cells of the leaf sheath were the site where most Na, Cl, and K were retained under salinity in the salt tolerant genotype FL478. Also, the concentration of $Na^+$, $K^+$ and $Cl^-$ ions in leaf sheaths and leaf blades was comparable between T65 and T65lg, indicating that the lamina joint may not be involved in the exclusion of $Na^+$, $Cl^-$ and $K^+$ by the leaf sheath from the leaf blade under salinity. Therefore, we conclude that the central parenchyma cells of basal part of leaf sheath are the site that plays a physiological role to exclude $Na^+$ in the shoots of rice without the involvement of the lamina joint.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.69-69
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• 2017

Due to the lack in storage facility, considerable amount of rice is stocked in the open air, which causes increased stale flavor and deteriorates palatability and merchantable quality. Lipoxygenase-3(LOX-3) is involved in the production of volatile constituents in stored rice, and the development of stale flavor is delayed in LOX-3 null rice. LOX activity in the rice grain is localized in bran fraction and the tropical Japonica cultivar 'Dawdam' was reported that the absence of LOX-3 is inherited as a simple recessive trait. Also, it was reported that the peroxidation of unsaturated fatty acids occurs at lower levels in the 'Dawdam' bran fraction during storage than in rice varieties with LOX-3. This study was conducted to develop LOX-3 null rice lines using 'Dawdam' and investigate changes of physicochemical properties of the lines stored at different storage temperatures and periods. So we analyzed texture, toyo glossiness value, germination rate and lipoxygenase activity of 15 LOX-3 null rice lines on the condition of which rough rice had been stored at different temperatures (high temperature condition at $35^{\circ}C$ and low temperature condition at $15^{\circ}C$ for 4months. Hardness and stickiness of the lines tendered to be increased when it was stored at high temperature and adhesiveness, springiness, cohesiveness and chewiness was not considerably different according to storage temperatures and periods. The germination rate of HR29062-B-98-2-1-B among LOX-3 null rice lines was higher than another lines, 99.3, 94.0% after 4months stored at low temperature and high temperature, respectively. The lipoxygenase activity was 3,304, 1,601unit/mg protein after 4months stored at low temperature and high temperatures, respectively. So, it is thought that this line will be useful to breed rice varieties with high storability after tested on agricultural traits.

• 식물조직배양학회지
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• 제22권6호
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• pp.317-322
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• 1995

속간교잡에 의한 신품종 육성을 위한 기초 연구로서 유자와 탱자를 정역교잡한 후 배주배양하였고, 자웅배우체 형성 및 수정현상을 조사하였다. 속간교잡의 결과율은 유자$\times$탱자가 16.6%, 탱자$\times$유자는 11.7%이었다. 수분후 6주된 배주를 MT 기본배지에 Zeatin 0.5 mg/L에 NAA 1 또는 3.0 mg/L에 배양했을 때 callus형성율이 높았지만, 14~15주된 배주를 2,4-D 0.1 mg/L 또는 0.5 mg/L이 첨가된 배지에 배양했을 때는 식물체 유기가 잘 되었다. 20주된 배주배양시 발아율은 유자 $\times$ 탱자의 경우 54.5%, 행자 $\times$ 유자는 48.6%이었다. F$_1$식물의 삼엽형 출현율은 유자$\times$탱자는 56.7%, 탱자$\times$유자는 100%이었다. 유자와 행자의 염색체수는 모두 n=9 (2n=18)이었고 화분립의 크기는 각각 33.75 $\mu$, 25.0 $\mu$이었다. 유자와 탱자 배낭의 길이와 폭은 69.38~79.23 $\mu$, 27.50~38.56 $\mu$, 난세포의 길이와 폭은 17.50~41.50 $\mu$, 6.25~8.12 $\mu$이었다. 수분 후 72시간이면 수정이 끝났다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권9호
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• pp.1334-1340
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• 2002

A 4 week experiment was designed to study the effects of replacing corn with Chinese brown rice or adding different amylase in brown rice basal diet on growth performance and apparent fecal digestibilities of nutrients in growing pigs. One hundred and eight cross-bred pigs (Duroc${\times}$Landrace${\times}$Large White), weighing an average of $18.35{\pm}0.12kg$, were randomly assigned to 6 treatments with 6 replications per treatment. Diet in treatment 1 was corn-soybean meal basal diet, and in treatment 2, 3 and 4, corn was replaced by brown rice on rates of 33.3%, 66.7% and 100% respectively on the basis of treatment 1. And diets in treatment 5 and 6 were similar to treatment 4 except two kinds of amylases, glucoamylase and ${\alpha}$-amylase, were added respectively. The brown rice used in this experiment was husked from one kind of early, long grain, non-glutinous rice (ELGNR, indica rice) in southern China. The results indicated that there was a slight improvement in growth performance of pigs in brown rice treatments (p>0.05). The blood urea nitrogen value in treatment 2 was lower than that in treatment 1 (p<0.05). The differences of apparent fecal digestibilities of most nutrients were significant (p<0.05) except CP. Digestibilities of GE, OM and DM in treatment 4 were the best and digestibility of crude fat in treatment 5 appeared best (p<0.05). Contrast results between treatment 1 and treatment 2 to 4 indicated that the digestibility of GE, OM and DM increased significantly with the replacing rates of brown rice (p<0.05). Contrast results between treatment 4 and 5 indicated that adding glucoamylase in brown rice diet increased growth performance slightly (p>0.05) but not for digestibilities. This experiment shows a positive effect of brown rice on growth performance, especially on nutrient digestibility.

• Asian-Australasian Journal of Animal Sciences
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• 제26권5호
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• pp.668-674
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• 2013

An in vitro fermentation was conducted to determine the effects of hainanmycin on protein degradation and populations of ammonia-producing bacteria. The substrates (DM basis) for in vitro fermentation consisted of alfalfa hay (31.7%), Chinese wild rye grass hay (28.3%), ground corn grain (24.5%), soybean meal (15.5%) with a forage: concentrate of 60:40. Treatments were the control (no additive) and hainanmycin supplemented at 0.1 (H0.1), 1 (H1), 10 (H10), and 100 mg/kg (H100) of the substrates. After 24 h of fermentation, the highest addition level of hainanmycin decreased total VFA concentration and increased the final pH. The high addition level of hainanmycin (H1, H10, and H100) reduced (p<0.05) branched-chain VFA concentration, the molar proportion of acetate and butyrate, and ratio of acetate to propionate; and increased the molar proportion of propionate, except that for H1 the in molar proportion of acetate and isobutyrate was not changed (p>0.05). After 24 h of fermentation, H10 and H100 increased (p<0.05) concentrations of peptide nitrogen and AA nitrogen and proteinase activity, and decreased (p<0.05) $NH_3$-N concentration and deaminase activity compared with control. Peptidase activitives were not affected by hainanmycin. Hainanmycin supplementation only inhibited the growth of Butyrivibrio fibrisolvens, which is one of the species of low deaminative activity. Hainanmycin supplementation also decreased (p<0.05) relative population sizes of hyper-ammonia-producing species, except for H0.1 on Clostridium aminophilum. It was concluded that dietary supplementation with hainanmycin could improve ruminal fermentation and modify protein degradation by changing population size of ammonia-producing bacteria in vitro; and the addition level of 10 mg/kg appeared to achieve the best results.

• Asian-Australasian Journal of Animal Sciences
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• 제14권9호
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• pp.1276-1281
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• 2001

The feeding values of four indigenous Kenyan sorghum cultivars and the effects of polyvinylpyrrolidone (PVP) on the utilization of high tannin sorghum by broiler chicks were studied in two 3-week feeding trials. In Experiment 1, one hundred and five broiler chicks (initial average weight 97 g) were randomly assigned to each one of the seven grain-soybean meal diets. The diets consisted of maize [diet 1; no assayable tannin], white sorghum [diet 2; 0.59% catechin equivalents (CE)], cream sorghum [diet 3; 0.94% CE], light brown sorghum [diet 4; 2.71% CE] and dark brown sorghum [diet 5; 3.54% CE]. Diets 6 and 7 were included to test the possibility of overcoming the detrimental effects of sorghum tannins by adding PVP at 0.25% and 0.5% to dark brown sorghum, which resulted in dietary tannin levels of 3.46% and 3.38% CE respectively. In Experiment 2, the effects of tannin on dry matter digestibility (DMD) and nitrogen (N) retention were studied in a 3-week substitution assay in which high tannin sorghum (5% CE) was substituted for white maize at different inclusion levels. Ninety broiler chicks aged 7 days (initial average weight 102 g) were randomly assigned to each one of the six diets. The diets consisted of corn gluten meal and fishmeal as protein sources plus maize [diet 1] and high tannin sorghum at different inclusion levels [diets 2, 3, 4, 5 and 6], resulting in dietary tannin levels of 0, 1.25%, 1.66%, 2.08%, 2.5% and 3.2% CE respectively. Feed intake, feed efficiency and body weight gain were measured weekly. In Experiment 2, tannin absorption, DMD and N retention were measured on days 19, 20 and 21. The results of Experiment 1 showed that feed intake, feed efficiency and body weight gain were all affected by treatment (p<0.05). Diets 1, 2 and 3 gave similar body weight gains and all were better than diets 4 and 5 (i.e. 504, 517, 473 g, vs. 256, 267 g). Similarly, feed efficiencies were higher (p<0.05) for diets 1, 2 and 3 compared to diets 4 and 5 (0.4, 0.42, 0.39 vs. 0.21, 0.23). When 0.25% PVP was added to the dark brown sorghum (diet 6) there was no significant improvement in chick performance (p>0.05). However, addition of 0.5% PVP (diet 7) resulted in significant improvement (p<0.05) in body weight gain compared to the untreated dark brown sorghum. Overall, PVP did not completely overcome the deleterious effects of tannins. The results of Experiment 2 indicate that sorghum inclusion level and subsequent tannin level had no effect on feed intake, feed efficiency, weight gain, DMD and N retention. The above results suggest that tannin level should be limited to below 2.71% CE in broiler chick diets containing 20% CP and 0.4% methionine. However, in diets with 23% CP and 0.8% methionine tannin level of up to 3.2% will not affect performance. Consequently high tannin sorghum (5% CE) can be used to substitute for white maize by up to 100% in broiler chick diets.

• Asian-Australasian Journal of Animal Sciences
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• 제19권6호
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• pp.892-897
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• 2006

An experiment was designed to study the nutritional value of Chinese brown rice and maize for growing pigs. Six male grower pigs (Duroc${\times}$Landrace${\times}$Large White, $24.3{\pm}1.26$ kg average initial BW) were surgically fitted with a simple T-cannula at the terminal ileum and allotted within a $2{\times}2$ Latin square design. The pigs were fed either a maize or brown rice diet in a direct method to determine their digestibility. The brown rice used in this experiment was husked from one kind of early, long grain, and non-glutinous rice (ELGNR, indica rice: non-waxy rice, containing amylopectin and amylose) in southern China. Chromic oxide was used as a marker. The diets were supplied at about 4.0% of body weight in dry matter/d. Total faeces and urine were collected on days 4 and 5; digesta was collected on days 6-8 in each period. The average body weight was 24.3 kg at the start of the experiment and 27.6 kg at the end. The results showed that the apparent ileal digestibilities of most amino acids of brown rice were significantly higher than those in maize (p<0.01), as were the apparent ileal digestibilities of crude protein (CP), digestible energy (DE), organic matter (OM) and dry matter (DM) (p<0.05). However, the apparent ileal starch digestibilities of the two treatments were similar (p>0.05). The values of the apparent faecal digestibilities derived from the two methods, marker and total faecal-collection methods, were very similar and also correlated with each other. The difference in absolute value of the apparent faecal digestibilities between brown rice and maize was smaller compared to that of the apparent ileal digestibilities. The net protein utilization was higher (p = 0.07) and the DE metabolizable rate was significantly higher (p<0.01) for brown rice than for maize. The metabolizable energy (ME) of brown rice is similar to that of maize, while the DE of brown rice was relatively lower. It can be concluded that Chinese brown rice are better than maize not only in apparent ileal digestibilities, but also in metabolizable rate of amino acids and gross energy under the present study conditions.