• 한국해양바이오학회지
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• 제8권2호
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• pp.45-53
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• 2016

Most of microalgae shift their metabolic pathways toward the fatty acid biosynthesis following nitrogen deprivation. Recent studies on Nannochloropsis species, oleaginous microalgae, have been performed to investigate the regulation of contents and compositions of fatty acids under stressful condition. The objective of this experiment is to identify the effect of nitrogen on cell growth and fatty acids production in Nannochloropsis oculata K-1281 and compare fatty acid composition response to nitrogen deficiency between N. oculata LB2164 and K-1281. The fatty acids content in N. oculata K-1281 was increased up to 210%, while the growth rate was decreased under nitrogen deficient condition. The contents of C16:0 and C16:1 increased dramatically in both N. oculata K-1281 and LB2164, while the contents of C20:4 and C20:5 increased in N. oculata LB2164. The fatty acids content and composition in N. oculata K-1281 returned following addition of nitrogen after nitrogen starvation. These results demonstrated that fatty acid contents and compositions under nitrogen deficiency will provide the understanding of fatty acid synthesis in microalgae.

• Journal of Plant Biology
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• 제17권3호
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• pp.127-136
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• 1974

The effect of potassium metabolism on the soybean leaves was studied with comparison of other elements during the successive growing period. The results were as follows; 1. The percentage of potassium content showed remarkable increase not only in the first compound leaf at a stage which was growing vigorously and producing new leaves, but also in the fifth compound leaf at a stage which was taking a active metabolism of nitrogen and carbohydrate but not producing new leaves. However, the percentage of potassium content was decreased in the second compound leaf than in the first one. Such a result could be regarded as a potassium removal from mature leaves into immature and flowing out from stoma through respiration. During the pod-development the percentage of potassium content in the soybean leaf was decreased. 2. If nitrogen, phosphorus and potassium were added excessively in the nutrient solution, the percentage of potassium content in the soybean leaf had increased. The effects of these elements showed a remakable increase in the excessive plot of nitrogen than in that of phosphorus. At early stage the redtarded effect of phosphorus on the growth of soybean could be covered by potassium, however, at late stage it could not. The growth of soybean plant was much more inhibited by potassium, compared with nitrogen and phosphorus. New leaves could not be produced in the potassium deficient soybean plant after the third compound leaf. The normal growth of soybean plant could not be observed if only one element was excessively added to the culture solution, compared with the deficiency of other two elements.

• 생물환경조절학회지
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• 제16권4호
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• pp.365-371
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• 2007

본 연구는 질소의 시비농도를 인위적으로 조절하여 잎들깨를 관비재배 하면서 질소의 시비수준이 생장과 결핍증상 발현에 미치는 영향을 구명하고, 생육을 우수하게 유지할 수 있는 식물체 및 토양의 한계농도를 밝히기 위하여 수행하였다. 질소 무시비구에서 지상부 식물생육의 심한 억제 현상과 노엽의 엽신 전체가 황화된 후 점차 괴사하는 결핍증상이 나타났다. 질소 시비농도가 높아질수록 정식 75일 후의 생체중과 건물중이 무거워졌고, 엽병 추출액의 $NO_3-N$ 농도와 토양 $NO_3-N$ 농도가 높아졌으나, 20mM 시비구에서는 질소과잉증상이 나타났다. $10{\sim}15mM$ 시비구에서 가장 바람직한 생장을 보였으며, 이때의 질소 함량은 건물중 기준으로 $0.9{\sim}1.25%$, 엽병추출액 및 1:2 추출법으로 분석한 토양의 $NO_3-N$ 농도가 각각 $800{\sim}3,300mg{\cdot}kg^{-1}$ 및 $28.7{\sim}47.3mg{\cdot}L^{-1}$ 범위에 포함되었다.

• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.854-866
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• 2016

The production cost of biodiesel from microalgae is still not competitive, compared with that of petroleum fuels. The genetic improvement of microalgal strains to increase triacylglycerol (TAG) accumulation is one way to reduce production costs. One of the most promising approaches is the isolation of starch-deficient mutants, which have been reported to successfully increase TAG yields. To date, such a stable mutant is not available in an oleaginous marine microalga, despite several advantages of using marine species for biodiesel production. Algae in the genus Dunaliella are known to tolerate high salt concentration and other environmental stresses. In addition, the cultivation processes for large-scale outdoor commercialization have been well established for this genus. In this study, Dunaliella tertiolecta was used to screen for starch-deficient mutants, using an iodine vapor-staining method. Four out of 20,016 UV-mutagenized strains showed a substantial reduction of starch content. A significantly higher TAG content, up to 3-fold of the wild-type level, was observed in three of the mutants upon induction by nitrogen depletion. The carotenoid production and growth characteristics of these mutants, under both normal and oxidative stress conditions, were not compromised, suggesting that these processes are not necessarily affected by starch deficiency. The results from this work open up new possibilities for exploring Dunaliella for biodiesel production.

• Journal of Animal Science and Technology
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• 제44권6호
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• pp.727-738
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• 2002

본 시험은 각각의 필수아미노산 결핍사료 섭취에 의한 단기간의 섭식반응과 methionine 결핍(-Met) 사료 섭취시 뇌내 각 부위에 나타나는 Fos 면역반응을 조사하여 아미노산 결핍이 뇌내 섭식반응과 관련있는 부위를 명확히 알고자 수행하였다. 실험사료의 단백질원은 정제아미노산을 이용하였다. 시험에 이용된 모든 사료의 질소원은 순수 아미노산 혼합물을 이용하였으며, 사료내 단백질 함량은 15%로 하였다. 사료는 하루 6시간 동안 섭취하도록 적응을 시켰으며(17:00${\sim}$21:00, meal feeding method), 사료섭취량과 증체량은 사료급여 7일째부터 매시간 측정하였다. 실험 1에서는 각 필수아미노산 결핍사료가 사료섭취량, 체중 변화 및 섭식패턴에 미치는 영향을 관찰하였고, 실험 2에서는 Fos 면역조직 화학적 방법을 사용하여 methio- nine 결핍사료에 대하여 회피 반응을 나타내는 동안에 활성을 보이는 뇌의 영역을 확인하였다. 각 필수아미노산 결핍사료 섭취에 따른 초기 섭식 억제 정도는 methionine이 가장 강하게 나타난 반면 threonine이 가장 약하였다. 결핍사료 급여 3일째의 사료섭취량은 대조구 사료에 비하여 histidine(71%), leucine(68%), isoleucine (66%), threonine(63%), tryptophan(61%), valine (55%), phenylalanine(52%), methionine(51%), lysine(44%), arginine(24%) 순으로 억제되었다. 뇌 신경 영역에 Fos 면역활성은 PPC, amygdala 및 endopyriform cortex(EPC) 부분이 대조구에 비하여 강한 활성을 나타냈으나, LH, VMH 및 PVM에서는 대조구와 처리구가 비슷하게 나타냈다. 따라서 본 연구의 결과로 미루어 뇌내 PPC는 필수아미노산 결핍에 반응하는 초기 인식부위라는 것을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권8호
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• pp.1186-1194
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• 2009

The objective of this study was to estimate the optimum dietary essential amino acid pattern for male Taiwan country chicks. A series of experiments was conducted with chicks, 14 d of age, for 2 wks. A basal synthetic diet was established using a dose response test for all essential amino acids referring to the broiler requirements recommended by NRC (1994). Twelve chicks were sacrificed at the beginning to provide initial body nitrogen data, and every group of six birds received the basal diet or a diet with a deficiency in a single essential amino acid in twenty one treatments by intubation according to their daily metabolic body weight (MBW). Deposited body nitrogen was determined using comparative slaughtering. According to the daily intake from the limiting amino acid per unit of MBW and the body nitrogen accretion rates for every two deficient groups with the same limiting amino acid but at different levels, a corresponding straight line was computed for each essential amino acid to intersect with a horizontal line made by the body nitrogen accretion rate of the control group. The x coordinate of the intersection represented the daily requirement for growth plus maintenance based on MBW corresponding to the essential amino acid. The amino acid ratios can be considered as the optimum pattern of dietary essential amino acids. The results, expressed with respect to lysine = 100, were arginine 105, methionine 81, histidine 34, tryptophan 18, leucine 103, phenylalanine 135, isoleucine 69, threonine 65 and valine 79. This pattern could be utilized to compute the dietary requirements (g/kg feed) for all essential amino acids by multiplying by the requirement of a single essential amino acid cited from the literature.

• Animal Bioscience
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• 제36권11호
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• pp.1666-1684
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• 2023

Objective: Our objective was to examine the relationships of supplemental rumen-protected lysine (RPL) or lysine + methionine (RPLM) on lactational performance, plasma amino acids (AA) concentration, and nitrogen use efficiency of lactating dairy cows by using a meta-analysis approach. Methods: A total of 56 articles comprising 77 experiments with either RPL or RPLM supplementation were selected and analyzed using a mixed model methodology by considering the treatments and other potential covariates as fixed effects and different experiments as random effects. Results: In early lactating cows, milk yield was linearly increased by RPL (β₁ = 0.013; p<0.001) and RPLM (β₁ = 0.014; p<0.028) but 3.5% fat-corrected milk (FCM) and energy-corrected milk (ECM) (kg/d) was increased by only RPL. RPL and RPLM did not affect dry matter intake (DMI) but positively increased (p<0.05) dairy efficiency (Milk yield/DMI and ECM/DMI). As a percentage, milk fat, protein, and lactose were unchanged by RPL or RPLM but the yield of all components was increased (p<0.05) by feeding RPL while only milk protein was increased by feeding RPLM. Plasma Lys concentration was linearly increased (p<0.05) with increasing supplemental RPL while plasma Met increased (p<0.05) by RPLM supplementation. The increase in plasma Lys had a strong linear relationship (R² = 0.693 in the RPL dataset and R² = 0.769 in the RPLM dataset) on milk protein synthesis (g/d) during early lactation. Nitrogen metabolism parameters were not affected by feeding RPL or RPLM, either top-dress or when supplemented to deficient diets. Lactation performance did not differ between AA-deficient or AA-adequate diets in response to RPL or RPLM supplementation. Conclusion: RPL or RPLM showed a positive linear relationship on the lactational performance of dairy cows whereas greater improvement effects were observed during early lactation. Supplementing RPL or RPLM is recommended on deficient-AA diet but not on adequate-AA diet.

• 한국가금학회지
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• 제38권1호
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• pp.37-43
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• 2011

본 연구는 맹장 결찰계를 이용하여서 [15N]urea의 이용성을 조사하였다. 질소의 balance 및 이용률은 맹장 결찰 수술에 의해서 높아지는 경향이 인정되었다. 이는 맹장 결찰 수술로 인한 요산 배설량의 유의한 감소로 인한 결과였다(사료 및 요소 유래 질소 이용률, P<0.01). 닭에 있어서 맹장 결찰 수술은 사료 유래 ammonia 배설량은 증가(P<0.01), 요소 유래 ammonia배설량은 감소(P<0.01)시켰다. 요소 유래, 요소질소의 배설량은 맹장 결찰 수술에 의해서 유의하게 증가하였지만(P<0.01), 맹장 결찰계도 5% 단백질 사료와 같이 급여한 요소를 51.6%정도 이용하는 것으로 나타났다. 결론적으로 닭에 있어서 단백질 수준이 결핍된 사료와 같이 급여된 요소의 이용에 있어서 맹장은 유의한 역할을 한다고 할 수 있다. 하지만 질소의 이용에 있어서는 반드시 긍정적인 역할만을 한다고는 결론내릴 수 없다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권3호
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• pp.434-442
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• 2008

The objective of this study was to determine the optimum ratio of methionine to methionine plus cystine for growing pigs. A nitrogen balance trial was conducted using a total of 21 barrows (Large WhiteLandrace) over two replicates. The initial body weight was $20.36{\pm}1.22kg$ (mean${\pm}$SD) in the first replicate and $23.54{\pm}1.02kg$ (mean${\pm}$SD) in the second. For each replicate, the 21 pigs were randomly assigned to one of seven dietary treatments with three observations per treatment. The diets included a methionine and cystine-deficient basal diet with all other essential nutrients meeting nutrient requirements and six diets formulated with graded levels of DL-methionine (0.00, 0.03, 0.06, 0.10, 0.13, 0.16%) and $L-Cystine{\cdot}HCl{\cdot}H_2O$ (0.19, 0.15, 0.11, 0.07, 0.04, 0.00%). This resulted in ratios of methionine to methionine plus cystine of 41.3, 29.6, 35.3, 41.2, 46.0, 51.6 and 57.5%. Each experimental period lasted 12 days consisting of a seven-day adaptation period followed by a five-day total collection of urine and feces. During the collection period, pigs were fed 900 g/day for the first replicate and 1,200 g/day for the second replicate. The feed was provided in three equal portions at 0800, 1500, and 2200 h daily. Pigs had ad libitum access to water after feeding. There was a linear (p<0.01) and quadratic (p<0.01) effect on daily gain and feed conversion as the ratio of methionine to methionine plus cystine increased. Pigs receiving the diets providing a methionine to methionine plus cystine ratio of 51.6% had the best daily gain and feed conversion. Plasma urea nitrogen was also lowest for this treatment. Nitrogen retention increased (p<0.01) as the relative proportion of methionine increased up to 51.6% and then a downward trend occurred at 57.5%. The quadratic regression model, as well as one- and two- slope regression line models, were used to determine the optimum ratio of methionine to methionine plus cystine. Eliminating the 35.3% methionine to methionine plus cystine treatment resulted in $R^2$ values in excess of 0.92. The optimal ratio of methionine to methionine plus cystine was estimated to be 54.15% for nitrogen retention and 56.72% for plasma urea nitrogen.

• Journal of Biosystems Engineering
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• 제24권6호
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• pp.539-546
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• 1999

오이를 공시재료로 하여, 생육중인 식물 잎으로부터 비교적 신속하게 생체정보 수집이 가능한 비파괴 계측기인 엽록소 측정기, 엽록소 형광측정기, 적외선 엽온측정기, 반사형 분광분석기를 이용하여 질소 결핍장해 오이의 조기 진단 가능성 여부와 그 유용한 정도를 파악하기 위하여 수행한 연구의 주요 결과는 다음과 같다. 1) 엽록소 측정기의 측정값으로서 질소 결핍장해 오이의 진단은 엽록소 함량 45 SPAD 이하 여부로서 판단할 수 있고, 이에 의한 질소 결핍 장해의 진단은 장해 발생 후 빠르면 3일 정도면 적중율 95%수준의 장해 진단이 가능하고 7∼10일 후엔 높은 정확도의 진단이 가능함을 알 수 있었다. 2) 엽록소 형광 측정에 의한 질소 결핍장해 오이의 진단은 장해 발생 후 빠르면 5일째부터 적중률 95%수준의 장해 진단이 가능하며, 이에 의한 오이의 질소 결핍장해 진단은 엽록소 함량 측정에 의한 진단보다는 우수하지 못하다. 그리고 대기-엽온차에 의해 질소 결핍장해 오이의 진단은 불가능한 것으로 판단되었다. 3) 분광분석기의 흡광도 분석에 의한 질소 결핍 진단의 민감 파장대는 562∼564 nm, 700∼724 nm, 1,886∼1,894 nm으로 분석되었다. 이러한 영역의 파장에 의한 질소 결핍장해 오이의 진단은 장해 발생후 3∼4일째부터 적중을 95%수준의 진단이 가능하며, 진단의 정확도는 본 연구에서 사용한 4가지 측정기 중 가장 우수하였다.