• 한국식품저장유통학회지
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• 제7권4호
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• pp.414-417
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• 2000

단백질분해효소를 생산하지 않는 균주 B. subtilis MT-2의 염색체 DNA를 추출한 다음, B. subtilis AC819 균주에 상동성 유전자재조합을 이용하여 competent cell 형질전환을 시켰다. 얻어진 형질전환체를 B. subtilis HL-1이라고 명명하였으며, 그 표현형은 histidine 요구성, streptomycin 내성, tetracyclin 내성을 나타내면서 단백질 분해효소를 생산하지 않았다. 플라스미드 pUB110 을 이용한 B. subtilis HL-1의 protoplst 형질전환율은 B. subtilis MT-2의 형질전환율보다 높았다. 따라서 새로운 B. subtilis HL-1균주는 단백질분해효소의 형질전환과 내열성 protease 유전자클로닝에서 숙주로 사용하는데 유용하다.

• 한국가시화정보학회지
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• 제15권1호
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• pp.53-63
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• 2017

Sonic and supersonic jets include many complicated flow physics associated with shock waves, shear layers, vortices as well as strong interactions among them, and have a variety of engineering applications. Much has been learned from the previous researches on the sonic and supersonic jets but quantitative assessment of these jets is still uneasy due to the high velocity of flow, compressibility effects, and sometimes flow unsteadiness. In the present study, the sonic jets issuing from a convergent nozzle were measured by PIV and Schlieren optical techniques. Particle Image Velocimetry (PIV) with Olive oil particles of $1{\mu}m$ was employed to obtain the velocity field of the jets, and the black-white and color Schlieren images were obtained using Xe ramp. A color filter of Blue-Green-Red has been designed for the color Schlieren and obtained from an Ink jet printer. In experiments, two types of sonic nozzles were used at different operating pressure ratios(NPR). The obtained images clearly showed the major features of the jets such as Mach disk, barrel shock waves, jet boundaries, etc.

• Molecules and Cells
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• 제42권1호
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• pp.28-35
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• 2019

Animals need to be able to alter their developmental and behavioral programs in response to changing environmental conditions. This developmental and behavioral plasticity is mainly mediated by changes in gene expression. The knowledge of the mechanisms by which environmental signals are transduced and integrated to modulate changes in sensory gene expression is limited. Exposure to ascaroside pheromone has been reported to alter the expression of a subset of putative G protein-coupled chemosensory receptor genes in the ASI chemosensory neurons of C. elegans (Kim et al., 2009; Nolan et al., 2002; Peckol et al., 1999). Here we show that ascaroside pheromone reversibly represses expression of the str-3 chemoreceptor gene in the ASI neurons. Repression of str-3 expression can be initiated only at the L1 stage, but expression is restored upon removal of ascarosides at any developmental stage. Pheromone receptors including SRBC-64/66 and SRG-36/37 are required for str-3 repression. Moreover, pheromone-mediated str-3 repression is mediated by FLP-18 neuropeptide signaling via the NPR-1 neuropeptide receptor. These results suggest that environmental signals regulate chemosensory gene expression together with internal neuropeptide signals which, in turn, modulate behavior.

• Advances in aircraft and spacecraft science
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• 제7권3호
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• pp.203-214
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• 2020

In many applications like the aircraft or the rockets/missiles, the flow from a nozzle needs to be expanded suddenly in an enlarged duct of larger diameter. The enlarged duct is provided after the nozzle to maximize the thrust created by the flow from the nozzle. When the fluid is suddenly expanded in an enlarged duct, the base pressure is generally lower than the atmospheric pressure, which results in base drag. The objective of this research work is to optimize the length to diameter (L/D) ratio of the enlarged duct using the CFD analysis in the flow field from the supersonic nozzle. The flow from the nozzle drained in an enlarged duct, the thrust, and the base pressure are studied. The Mach numbers for the study were 1.5, 2.0 and 2.5. The nozzle pressure ratios (NPR) of the study were 2, 5 and 8. The L/D ratios of the study were 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. Based on the results, it is concluded that the L/D ratio should be increased to an optimum value to reattach the flow to an enlarged duct and to increase the thrust. The supersonic suddenly expanded flow field is wave dominant, and the results cannot be generalized. The optimized L/D ratios for various combinations of flow and geometrical parameters are given in the conclusion section.

• Preventive Nutrition and Food Science
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• 제3권3호
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• pp.241-247
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• 1998

Fish extracts were processed at high temperature (136.7 ~14$0^{\circ}C$) for possible use as functional food ingredients. Raw fish meats and those hydrothermal extracts were compared with respect to in vitro and in vivo protein qualities. 95% of fat inraw meats was reduced in extracts but there were not remarkable changes in other macronutrients in freeze-dried extracts. Most of essential amino acids were decreased significantly but two times more proline and glycine were detected in extracts. High temperature cooking resulted 2.1 ~3.7 times of higher total free amino acid content infish extracts compared iwth raw meat, and taurine and glutamic acid were increased especially. Severe protein damages were occurred when invitro protein quality indices such as availblae lysine, hydrophilic browing, trypsin inhibitor formation and in vitro protein digestibility were measured on fish extracts. In vivo protein qualities were also strongly influenced by high temperature ; however rat-body-weight gain was nearly zero during PER assay, and rat PER or NPR of fish extracts were significantly lower (p<0.001) than those of cotnrol (ANRC casein) and original raw fish meats.

• Fisheries and Aquatic Sciences
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• 제25권11호
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• pp.559-571
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• 2022

Galectins, a family of ß-galactoside-binding lectins, have emerged as soluble mediators in infected cells and pattern recognition receptors (PRRs) responsible for evoking and regulating innate immunity. The present study aimed to evaluate the role of galectin-1 in the host immune response of redlip mullet (Liza haematocheilia). We established a cDNA database for redlip mullet, and the cDNA sequence of galectin-1 (LhGal-1) was characterized. In silico analysis was performed, and the spatial and temporal expression patterns in gills and blood in response to lipopolysaccharide polyinosinic:polycytidylic acid, and Lactococcus garvieae were estimated via quantitative real-time PCR. Functional assays were conducted using recombinant protein to investigate carbohydrate binding, bacterial binding, and bacterial agglutination activity. LhGal-1 was composed of 135 amino acids. Conserved motifs (H-NPR, -N- and -W-E-R) within the carbohydrate recognition domain were found in LhGal-1. The tissue distribution revealed that the healthy stomach expressed high levels of LhGal-1. The temporal monitoring of LhGal-1 mRNA expression in the gill and blood showed its significant upregulation in response to immune challenges with different stimulants. rLhGal-1 exhibited binding activity in response to carbohydrates and bacteria. Moreover, the agglutination of rLhGal-1 against Escherichia coli was observed. Collectively, our findings suggest that LhGal-1 may function as a PRR in redlip mullet. Furthermore, LhGal-1 can be considered a significant gene to play a protective role in redlip mullet immune system.

• The Plant Pathology Journal
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• 제29권2호
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• pp.193-200
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• 2013

Trichoderma asperellum SKT-1 is a microbial pesticide that is very effective against various diseases. Our study was undertaken to evaluate T. asperellum SKT-1 for induction of resistance against yellow strain of Cucumber mosaic virus (CMV-Y) in Arabidopsis plants. Disease severity was rated at 2 weeks post inoculation (WPI). CMV titre in Arabidopsis leaves was determined by indirect enzyme-linked immunosorbent assay (ELISA) at 2 WPI. Our results demonstrated that among all Arabidopsis plants treated with barley grain inoculum (BGI) of SKT-1 NahG and npr1 plants showed no significant reduction in disease severity and CMV titre as compared with control plants. In contrast, disease severity and CMV titre were significantly reduced in all Arabidopsis plants treated with culture filtrate (CF) of SKT-1 as compared with control plants. RT-PCR results showed increased expression levels of SA-inducible genes, but not JA/ET-inducible genes, in leaves of BGI treated plants. Moreover, expression levels of SA- and JA/ET-inducible genes were increased in leaves of CF treated plants. In conclusion, BGI treatment induced systemic resistance against CMV through SA signaling cascade in Arabidopsis plants. While, treatment with CF of SKT-1 mediated the expression of a majority of the various pathogen related genes, which led to the increased defense mechanism against CMV infection.

• 자원환경지질
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• 제41권2호
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• pp.225-242
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• 2008

이 연구에서는 coda파 스펙트럼 비를 이용하여 한반도 남부의 광대역 지진관측소 23개소에 대한 부지효과를 추정하였다. 원리적으로 부지효과는 지진원과 전달과정중의 감쇠효과를 제외한 관측소 하부에서의 순수한 증폭효과만을 의미한다. 그러나 이 연구에서 구한 부지효과는 모든 관측소의 평균값에 대한 상대적인 부지증폭률과 같다. 2001년 1월부터 2007년 1월 사이에 발생한 규모 2.5부터 5.1까지의 지진 35개로부터 기록된 500개의 3성분 파형이 부지증폭효과를 얻기 위해 사용되었다. 부지증폭률은 중심주파수를 0.2, 0.5, 1,2, 5, 10, 15, 및 20 Hz로 하는 주파수대역에 대해서 계산하였다. 횡단성분과 방사성분의 수평 2성분에 대한 부지증폭률은 모든 주파수 대역에서 서로 일치하나, 수직성분의 증폭률은 수평성분에 비하여 일관되게 낮게 나타났다. 또한 증폭률은 저주파 보다는 고주파에서 일반적으로 증폭의 정도가 큰 경향을 보였다. 부지증폭률은 2 Hz 이하의 저주파에서 1.5 이상의 높은 값을 갖는 기상청과 한국지질자원연구원의 백령도 관측소(BRD1과 BRD2)를 제외한 나머지 관측소에서 0.5와 1.5사이의 값을 갖는다. SEO, SNU, HKU, NPR 및 GKP1 관측소들은 5${\sim}$20Hz범위의 고주파 대역에서 1.5 이상의 높은 값을 보였으며, 특히 GKP1 관측소는 1.8${\sim}$7.8 범위의 높은 증폭값이 나타났다. 또한 KWJ, SND 및 ULJ 관측소는 0.5이하의 낮은 값을 나타내었다. 부지증폭률의 공간적 분포는 한반도 남부에서 대체로 북동부가 남서부에 비해 증폭의 정도가 낮은 경향을 보여 준다.

• 한국추진공학회지
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• 제23권3호
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• pp.28-34
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• 2019

공압시험용 플러그 노즐 구동에 따른 추력제어, 핀틀 형상 및 작동압력에 따른 유동특성 분석을 수행하였다. 이를 위해 시험에서의 유동구조와 추력계수를 비교함으로써 수치해석의 타당성을 확인하였다. 이후 각 노즐형상이 설계의도지점에 노즐목이 형성됨과 원뿔형 노즐에 대하여 핀틀 구동만으로 1:8의 추력제어가 가능함을 확인하였다. 마지막으로 고도보정 효과가 뛰어난 에어로 스파이크 노즐일지라도, 너무 낮은 NPR에 맞춰 설계된 경우, 부족팽창 조건에서 불리할 가능성을 확인하였다.

• The Plant Pathology Journal
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• 제37권6호
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• pp.632-640
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• 2021

Cucumber mosaic virus (CMV) and Pepper mild mottle virus (PMMoV) causes severe economic loss in crop productivity of both agriculture and horticulture crops in Korea. The previous surveys showed that naturally available biopolymer material - chitosan (CS), which is from shrimp cells, reduced CMV accumulation on pepper. To improve the antiviral activity of CS, it was synthesized to form phosphate cross-linked chitosan (PCS) and compared with the original CS. Initially, the activity of CS and PCS (0.01%, 0.05%, and 0.1% concentration) compound against PMMoV infection and replication was tested using a half-leaf assay on Nicotiana glutinosa leaves. The total number of local lesions represented on a leaf of N. glutinosa were counted and analyzed with phosphate buffer treated leaves as a negative control. The leaves treated with a 0.1% concentration of CS or PCS compounds exhibited an inhibition effect by 40-75% compared with the control leaves. The same treatment significantly reduced about 40% CMV accumulation measured by double antibody sandwich enzyme-linked immunosorbent assay and increased the relative expression levels of the NPR1, PR-1, cysteine protease inhibitor gene, LOX, PAL, SRC2, CRF3 and ERF4 genes analyzed by quantitative reverse transcriptase-polymerase chain reaction, in chili pepper plants.