• 한국작물학회지
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• 제50권2호
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• pp.84-90
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• 2005

The effects of UV-B radiation on the seedling growth, carbohydrate metabolism and antioxidants activities of rice (Oryza sativa L.) were investigated under environmentally controlled chamber. Supplementary UV­B radiation reduced dry matter as well as leaf area, there­fore, relative growth rates (RGR) of seedlings were decreased by up to half compared to control. Photosynthetic products such as soluble sugars and starch were rapidly and significantly reduced by within 1 day of enhanced UV-B radiation due to the inhibition and degradation of photosynthetic processes and thylakoid membrane integrity. In our study, nonstructural carbohydrate levels were proved to be a main indicator on UV-B­induced stress. The behavior of SOD, CAT, APX and POD activities was monitored in the leaves of rice seedlings subjected to UV-B radiation. Under UV-B treatments, SOD activity was initially increased, whereas CAT and POD activities were slowly and slightly increased. However, APX activity showed no presumable results with an increase of UV-B dose. In leaves of rice seedlings, supplementary UV-B radiation caused an increase in free putrescine and spermidine, however spermine remained unaltered, although 24-hrs UV-B treatment slightly increased. This result presumes that an excess UV-B dose may induce ethylene biosynthesis (senescence) rather than polyamine biosynthesis (defense).

• 한국작물학회지
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• 제49권2호
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• pp.110-115
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• 2004

Rice (Oryza sativa L.) plants were cultivated to examine changes in antioxidative defence mechanism induced by elevated ozone levels. Catalase activities in tolerant Jinpumbyeo and susceptible Chucheongbyeo under ozone fumigation were reduced at 5 hrs and 3 hrs after ozone fumigation, respectively. With the increased ozone supply, peroxidase activity in Jinpumbyeo was steadily enhanced whereas in Chucheongbyeo it was not changed. Four SOD-isozymes were detected by NBT staining of native-PAGE. Two isozymes of them were obviously induced by ozone supply, particularly in Jinpumbyeo. The continuous ozone fumigation increased remarkably putrescine levels in leaves whereas it did not affect the levels of spermidine and spermine. In this study, it was implied that ozone in cell inhibits strongly diamine oxidase and thus promotes ethylene biosynthesis which will cause the senescence in rice plants.

• 생체재료학회지
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• 제22권4호
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• pp.328-336
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• 2018

Background: Biogenic fabrication of silver nanoparticles from naturally occurring biomaterials provides an alternative, eco-friendly and cost-effective means of obtaining nanoparticles. It is a favourite pursuit of all scientists and has gained popularity because it prevents the environment from pollution. Our main objective to take up this project is to fabricate silver nanoparticles from lichen, Usnea longissima and explore their properties. In the present study, we report a benign method of biosynthesis of silver nanoparticles from aqueous-ethanolic extract of Usnea longissima and their characterization by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses. Silver nanoparticles thus obtained were tested for antimicrobial activity against gram positive bacteria and gram negative bacteria. Results: Formation of silver nanoparticles was confirmed by the appearance of an absorption band at 400 nm in the UV-vis spectrum of the colloidal solution containing both the nanoparticles and U. longissima extract. Poly(ethylene glycol) coated silver nanoparticles showed additional absorption peaks at 424 and 450 nm. FTIR spectrum showed the involvement of amines, usnic acids, phenols, aldehydes and ketones in the reduction of silver ions to silver nanoparticles. Morphological studies showed three types of nanoparticles with an abundance of spherical shaped silver nanoparticles of 9.40-11.23 nm. Their average hydrodynamic diameter is 437.1 nm. Results of in vitro antibacterial activity of silver nanoparticles against Staphylococcus aureus, Streptococcus mutans, Streptococcus pyrogenes, Streptococcus viridans, Corynebacterium xerosis, Corynebacterium diphtheriae (gram positive bacteria) and Escherichia coli, Klebsiella pneuomoniae and Pseudomonas aeruginosa (gram negative bacteria) showed that it was effective against tested bacterial strains. However, S. mutans, C. diphtheriae and P. aeruginosa were resistant to silver nanoparticles. Conclusion: Lichens are rarely exploited for the fabrication of silver nanoparticles. In the present work the lichen acts as reducing as well as capping agent. They can therefore, be used to synthesize metal nanoparticles and their size may be controlled by monitoring the concentration of extract and metal ions. Since they are antibacterial they may be used for the treatment of bacterial infections in man and animal. They can also be used in purification of water, in soaps and medicine. Their sustained release may be achieved by coating them with a suitable polymer. Silver nanoparticles fabricated from edible U. longissima are free from toxic chemicals and therefore they can be safely used in medicine and medical devices. These silver nanoparticles were stable for weeks therefore they can be stored for longer duration of time without decomposition.

• Journal of Microbiology and Biotechnology
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• 제33권4호
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• pp.552-558
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• 2023

Levulinic acid (LA) is a valuable chemical used in fuel additives, fragrances, and polymers. In this study, we proposed possible biosynthetic pathways for LA production from lignin and poly(ethylene terephthalate). We also created a genetically encoded biosensor responsive to LA, which can be used for screening and evolving the LA biosynthesis pathway genes, by employing an LvaR transcriptional regulator of Pseudomonas putida KT2440 to express a fluorescent reporter gene. The LvaR regulator senses LA as a cognate ligand. The LA biosensor was first examined in an Escherichia coli strain and was found to be non-functional. When the host of the LA biosensor was switched from E. coli to P. putida KT2440, the LA biosensor showed a linear correlation between fluorescence intensity and LA concentration in the range of 0.156-10 mM LA. In addition, we determined that 0.156 mM LA was the limit of LA detection in P. putida KT2440 harboring an LA-responsive biosensor. The maximal fluorescence increase was 12.3-fold in the presence of 10 mM LA compared to that in the absence of LA. The individual cell responses to LA concentrations reflected the population-averaged responses, which enabled high-throughput screening of enzymes and metabolic pathways involved in LA biosynthesis and sustainable production of LA in engineered microbes.

• 화훼연구
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• 제19권3호
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• pp.139-143
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• 2011

본 연구는 에틸렌 작용 억제제 중 하나인 1-methylcyclopropene(MCP)이 알스트로메리아, 금어초, 다알리아 및 나리의 절화수명에 미치는 영향을 알아보기 위하여 실시하였다. 4종의 절화에 1-MCP 250, 500, 750 ppb를 각각 12시간 처리하였다. 알스트로메리아의 경우 개화소요일수는 대조구와 1-MCP 모든 처리구에서 유의차가 없었다. 절화수명은 대조구보다 처리구에서 2일 이상 연장되었으며, 250 ppb 처리구가 17.1일로 가장 길었다. 금어초는 잔여소화율이 대조구와 비교하여 1-MCP 모든 처리구에서 높아졌다. 그러나 절화수명은 대조구와 처리구 사이에 유의차가 없었다. 다알리아의 절화수명은 1-MCP 처리시 대조구보다 2일 정도 연장되었다. 수분흡수량은 절화수명과 반대 양상을 나타내었다. 나리의 절화수명은 대조구 12.6일과 비교하여 모든 처리구간 유의차가 없었다. 수분흡수량의 경우 대조구와 비교할 때 1-MCP 750 ppb 처리구에서 약 3 mL 더 많았다.

• 한국육종학회지
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• 제42권5호
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• pp.565-573
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• 2010

사과의 경우 한 과총에 5개의 꽃이 피는데 그 중 한 가운데의 중심화가 먼저 개화하여 과일로 발달하고 주위의 측과 4개는 스스로 낙과되는 현상을 자가적과성이라고 한다. 적과는 인위적으로 과실의 숫자를 줄여 잎 수와 과실 수의 균형을 맞추는 작업으로 과실의 크기를 증가시키고, 수세, 수형을 유지시켜 안정적인 생산에 도움을 준다. 노동력 절감을 위해 인간에게 유용하게 사용될 수 있는 특성이 자가적과성인데, 자가적과성 품종의 사과에서 측과는 만개 후 30일 이내에 떨어지고 중심과만 남아서 성숙하게 된다. 51개의 사과 품종으로부터 비자가적과성 그룹 20종, 6월 생리적 낙과 그룹 16종, 자가적과성 그룹 15종을 분류하였다. 대표적인 자가적과성 품종인 Aori #9 로부터 중심과와 측과에서 다르게 발현이 되는 유전자들을 DD-PCR 방법으로 확인하였다. 중심과에서 30개의 clones 과 측과에서 24개의 clones을 선발하여 염기서열을 분석하였다. 주로 측과에서 발현되는 유전자들은 pathogenesis, senescence, temperature stress, protein degradation, fruit browning, sorbitol metabolism에 관여하는 유전자들과 높은 상동성을 나타내고, 중심과에서 발현되는 유전자들의 염기서열을 분석해 보면 anthocyanin의 up-regulation이나 flavonol 생합성, ethylene 생합성에 관여하는 유전자들이 분포한다. Cytochrome P450 유전자의 발현양상을 보기 위해 Real time PCR 분석을 한 결과 중심과보다 측과에서 발현량이 높게 나타났다. 중심과와 측과에서 다르게 발현되는 유전자들의 실제 발현양상을 분석하기 위해 Real time PCR을 이용해서 상대정량을 분석할 계획이며 분자수준에서의 자가적과를 조절하는 기작에 대한 앞으로의 연구는 생력 재배가 가능한 품종 육성의 육종 소재 개발에 활용될 수 있을 것이다.

• BMB Reports
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• 제37권3호
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• pp.343-350
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• 2004

A cDNA clone for a salicylic acid-induced gene in Chinese cabbage (Brassica rapa subsp. pekinensis) was isolated and characterized. The cabbage gene encoding a protein of 392 amino acids contained a tandem array of two thiJ-like sequences. ThiJ is a thiamin biosynthesis enzyme that catalyzes the phosphorylation of hydroxymethylpyrimidine (HMP) to HMP monophosphate. Although the cabbage gene shows a similarity to bacterial thiJ genes, it also shares a similarity with the human DJ-1, a multifunctional protein that is involved in transcription regulation, male fertility, and parkinsonism. The cabbage thiJ-like gene is strongly induced by salicylic acid and a nonhost pathogen, Pseudomonas syringae pv. tomato, which elicits a hypersensitive response in Chinese cabbage. Treatment of the cabbage leaves with BTH, methyl jasmonate, or ethephon showed that the cabbage thiJ-like gene expression is also strongly induced by BTH, but not by methyl jasmonate or ethylene. This indicates that the cabbage gene is activated via a salicylic acid-dependent signaling pathway. Examination of the tissue-specific expression revealed that the induction of the cabbage gene expression by BTH occurs in the leaf, stem, and floral tissues but not in the root.

• 원예과학기술지
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• 제30권6호
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• pp.734-742
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• 2012

본 연구는 배추의 유전자 기능분석을 위한 RNAi 유전자 침묵 기법과 T-DNA 삽입 기법을 비교하기 위해 수행하였다. 두 종류의 형질전환 계통이 이용되었으며 BrSAMS-knockout(KO) 계통은 T-DNA 삽입으로 한 개의 Brassica rapa S-adenosylmethionine synthetase(BrSAMS) 유전자가 기능을 상실한 계통이었으며 BrSAMS-knockdown(KD) 계통은 RNAi 방법을 통해 BrSAMS 유전자들의 발현이 억제된 계통이었다. KO 계통과 KD 계통의 microarray 분석 결과에서는 SAMS 유전자와 관련된 sterol, 자당, homogalacturonan 생합성 및 glutaredoxin-related protein, serine/threonine protein kinase, 그리고 gibberellin-responsive protein 유전자들의 발현 수준이 뚜렷한 차이를 보여 주었다. 그러나 KO 계통의 유전자 발현 양상은 하나의 BrSAMS 유전자가 기능을 상실하였음에도 불구하고 대조 계통과 비교하여 RNAi기법을 적용한 KD 계통에 비해 큰 차이를 보여주지 못했다. 또한 직접적으로 SAMS 유전자와 관련된 폴리아민과 에틸렌 합성 유전자들의 발현 변화도 KD 계통에서 더 잘 나타났다. 본 연구에서 microarray 결과를 이용한 KO 계통의 BrSAMS 기능분석은 배추과식물의 게놈 triplication 발생으로 인하여 다수로 존재하는 SAMS 유전자들 때문에 명확한 결론을 얻을 수 없었다. 결론적으로 배추와 같은 배수체 작물의 유전자 기능 분석은 RNAi silencing에 의한 유전자 knock-down 기법이 T-DNA 삽입에 의한 knock-out 기법보다 더욱 효율적인 것으로 나타났다.

• Molecules and Cells
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• 제26권6호
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• pp.536-547
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• 2008

Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzed the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. The full-length cDNA and genomic DNA sequences of ANS gene (designated as GbANS) were isolated from Ginkgo biloba for the first time. The full-length cDNA of GbANS contained a 1062-bp open reading frame (ORF) encoding a 354-amino-acid protein. The genomic DNA analysis showed that GbANS gene had three exons and two introns. The deduced GbANS protein showed high identities to other plant ANSs. The conserved amino acids (H-X-D) ligating ferrous iron and residues (R-X-S) participating in 2-oxoglutarate binding were found in GbANS at the similar positions like other ANSs. Southern blot analysis indicated that GbANS belonged to a multi-gene family. The expression analysis by real-time PCR showed that GbANS expressed in a tissue-specific manner in G. biloba. GbANS was also found to be up-regulated by all of the six tested abiotic stresses, UV-B, abscisic acid, sucrose, salicylic acid, cold and ethylene, consistent with the promoter region analysis of GbANS. The recombinant protein was successfully expressed in E. coli strain with pET-28a vector. The in vitro enzyme activity assay by HPLC indicated that recombinant GbANS protein could catalyze the formation the cyanidin from leucocyanidin and conversion of dihydroquercetin to quercetin, suggesting GbANS is a bifunctional enzyme within the anthocyanidin and flavonol biosynthetic pathway.

• Journal of Plant Biotechnology
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• 제41권3호
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• pp.159-167
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• 2014

진핵생물의 유전자 발현 과정에서 생성된 단백질은 전사후 변형 과정을 통해 소포체와 골지체에서 당질화가 일어난다. 당질화된 당단백질은 접힘의 오류가 있는 경우를 비롯하여 식물의 분화 조절 등의 경우 당단백질이 분해되며, 이 때 PNGase에 의해 N-당사슬이 단백질의 아스파라긴산 잔기로부터 절단된다. 그러나 식물의 발달과 분화 과정에서 PNGase의 발현 조절에 대해서는 거의 알려진 바가 없다. 기존에 보고된 유전적 정보를 활용하여 토마토의 잎에서 제조된 cDNA library에서 nested RT-PCR을 통하여 PNGase T의 유전자(GenBank Accession number KM401550)를 분리하였는데 이의 ORF는 1,767 bp, 588개의 이미노산으로 이루어졌으며, 분자량은 65.8 KDa이었다. PNGase T의 유전자는 토마토 과육에서 높은 수준으로 항시적으로 발현되었으며, 특히 녹색과보다는 오렌지색으로 숙성되는 과정에서 PNGase T의 전사체량이 크게 증가하였다. 이러한 발현 패턴은 토마토 과육에서 세포죽음의 과정에서 증가하는 단백질 가수분해 효소인 metacaspase의 전사체 증가 페턴과 유사하였으며, 이 시기에는 에틸렌의 생합성 효소 중 노화관련 ACC synthase의 유전자 members (LeACS2, LeACS4, LeACS6)의 발현 패턴과도 유사하였다. 따라서 토마토 과육에서 PNGase T의 유전자 발현은 거대분자가 분해되는 시기에서 과육의 숙성과 노화 과정에서 특이적인 생리적 기능을 나타내는 것으로 판단된다. 향 후 고가의 의약용 재조합단백질의 면역부작용을 완화하기 위하여 식물체 유래의 당단백질의 탈당질화과정에서 PNGase T를 활용함으로써 식물생명공학 분야에서 활용가치가 높을 것으로 사료된다.