• Ocean and Polar Research
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• 제41권2호
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• pp.89-97
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• 2019

Long chain plant waxes (n-alkanes, n-alkanoic acids, and n-alcohols) and their carbon isotopic compositions (${\delta}^{13}C$) in geologic archives are valuable tools for paleovegetation reconstruction. However, the sensitivity of different plant wax constituents to vegetation shift is not well understood. This study explores controls on the variation in ${\delta}^{13}C$ values of long-chain n-alkanes ($C_{27}$ to $C_{33}$) and n-alkanoic acids ($C_{26}-C_{30}$) in the Gulf of Mexico core sediments (ODP 625B) near the Mississippi River delta. n-Alkanoic acids' ${\delta}^{13}C$ values were higher than those of n-alkanes by 1-2‰ on average and such a pattern is the opposite from their isotope fractionation observed in living plants: 1-2‰ smaller in n-alkanes than n-alkanoic acids. We attribute this offset to contributions from aquatic plants or microbes that produce high concentrations of $^{13}C-enriched$ long-chain n-alkanoic acids. The sensitivity of n-alkanes and n-alkanoic acids to vegetation and climate varied among chain lengths. The $n-C_{33}$ alkanes were most sensitive to $C_4$ grassland expansion among n-alkane homologues, while no specific trend was observed in n-alkanoic acids. This is due to the similarity in n-alkanoic acid concentrations between $C_3$ and $C_4$ plants by homologues and low terrestrial plant-derived n-alkanoic acid contributions to the sediments. The results of this study suggest that long chain n-alkanoic acids' ${\delta}^{13}C$ values in sediments may be influenced by contributions from different sources such as aquatic plants or microbial inputs and therefore interpretations regarding this matter should be cautiously formulated. We suggest that there is a need for further studies on characterizing long-chain n-alkanoic acids ($C_{26}-C_{34}$) in aquatic plants and microbes from various climates and environments in order to investigate their production and integration into sedimentary archives.

• Journal of Applied Biological Chemistry
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• 제51권6호
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• pp.253-261
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• 2008

Isoflavone daidzein is a phytoestrogen widely distributed in Leguminosae and is especially rich in the soybean. The C6-C3 (rings B and C) unit of isoflavones is derived from the phenylpropanoid pathway and the remaining C6 (ring A) unit is from the polyketide pathway. This unique carbon skeleton is the result of isomerization of the flavone catalyzed by the isoflavone synthase, a cytochrome P450 enzyme. The isoflavones daidzein and genistein are present in the plant mostly in the glucosylated forms. However, in the human intestine, the glycosidic linkage is broken, and the free form is uptaked into blood stream. The free form is further metabolized into various reduction products to end up at the equol, which is known to have the most potent estrogenic effect among the metabolites. Several human intestinal bacteria that can convert daidzein into equol have been described, and the study into the chemistry and biochemistry of the daizein reduction would be rewarding to the improvement of the human health.

• KSBB Journal
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• 제13권2호
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• pp.220-222
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• 1998

페놀수지인 resole을 유일 탄소원으로 분해할 수 있는 능력을 가진 3개의 미생물 컨소시염이 분리되었다. 이들 마생물 컨소시 염은 페놀수지 resole 제조공장 주변의 토양샘플로 부터 유래하였다.그들 컨소시엄 가운데 MS2로 명명된 미생물 컨소시엄은 배양 12일 이내에 초기에 배지내에 주어진 resole (100 mg/L) 의 70%까지 분해되었으나, 완전분해는 이루어지지 않았다 배양 기간동안 pH가 7.0에서 2.7로 감소되었으며 이러한 조건하에서 resole 분해는 억제되었다 UV /vis-spectrophotometer가 잔존 resole의 정량적 측정을 위하여 이용되었으며, 배양가간중에 채 취된 시료에서 resole의 농도는 UV-scans으로 261 nm에서 최대 흡광치룹 토대로 측정되었다.

• 한국육종학회지
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• 제42권4호
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• pp.351-356
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• 2010

Brachypodium distachyon is rapidly emerged in biological study and has been currently used as a model system for genetics and functional studies for crop improvement and biofuel production. Phosphinothricin (PPT) has been widely used as a selectable agent, which raises ammonium content and induces toxicity in non-transformed plant cells. However PPT selection is not much effective on Brachypodium callus consequently reducing transformation efficiency. In order to identify the efficient conditions of PPT selection, calli obtained from mature seeds of Brachypodium (PI 254867) were cultured on the callus inducing medium (CIM) or regeneration medium (ReM) containing serial dilutions of the PPT (0, 2, 5, 10, and 15 mg/l) in dark or light condition. Callus growth and ammonium content of each treatment were measured 2 weeks after the treatment. Although callus growth and ammonium content did not show much difference in CIM, slow callus growth and increased ammonium accumulation were found in ReM. No significant difference of ammonium accumulation in response to PPT was found between dark and light conditions. In order to identify major factors affecting increased ammonium accumulation, callus was cultured on the media in combined with phytohormones (2,4-D or kinetin) and carbon sources (sucrose or maltose) containing with PPT (5 mg/l). The highest ammonium content in callus was found in the kinetin and maltose media.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.812-818
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• 2001

Alginate and alginate-derived oligomannuronate enhanced penicillin production in shake flask and fermentor cultures of Penicillium chrysogenum Wis 54-1255 (containing a single copy of the penicillin gene cluster) and in the high producter strain P. chrysogenum AS-P-99 (containing multiple copies of the penicillin gene cluster). Alginate was not used as a single carbon source by P. chryogenum. The stimulatory effect on penicillin production was observed in a defined medium and, to a lower extent, in a complex production medium containing corn steep liquor. Alginate-supplemented cells showed higher transcript levels of the three penicillin biosynthetic genes, pcbAB, pcbC, and penDE, than cells grown in the absence of alginate. The promoters of the pcbAB, pcbC, and penDE genes were coupled to the reporter lacZ gene and introduced as monocopy constructions in P. chrysogenum Wis 54-1225 npe10 by targeted integration in the pyrG locus; the reporter ${\beta}$-galactosidase activity expressed from the three promoters was stimulated by alginate added to the culture medium of the transformants. These results indicate that the stimulation of penicillin production by alginate was derived from an increase in the transcriptional activity of the penicillin biosynthesis genes. The induction by alginate of the transcription of the three penicillin biosynthetic genes is good example of the coordinated induction of secondary metabolism genes by elicitors of plant (or microbial) origin.

• 공업화학
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• 제23권3호
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• pp.333-338
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• 2012

본 연구에서는 비성형 RDF의 에너지 활용성을 확인하기 위하여 실험실 연소로를 이용한 온도 변화에 의한 연소특성연구를 하였다. 비성형 RDF 연소시 배출가스의 특성과 분진 및 잔류물을 분석하였으며 또한 그 결과를 성형 RDF의 연소실험 결과와 비교분석하였다. 본 연구로부터 비성형 RDF가 성형 RDF에 비교하여 연소속도가 빨라져서 급격히 산소량이 감소되어 불완전연소율이 증가함을 확인하였다. 또한 연소온도가 높아질수록 연소속도가 향상되었으며 산소 소모량이 급격히 증가하였고, 이에 따른 불완전연소율이 증가하여 CO의 농도가 높아짐을 알 수 있었다. 따라서 비성형 RDF의 완전연소를 위한 운전조건의 설정에 매우 신중을 기해야 할 것으로 판단되었다.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.404-416
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• 2020

Bacteria that are resistant to high temperatures and alkaline environments are essential for the biological repair of damaged concrete. Alkaliphilic and halotolerant Bacillus sp. AK13 was isolated from the rhizosphere of Miscanthus sacchariflorus. Unlike other tested Bacillus species, the AK13 strain grows at pH 13 and withstands 11% (w/v) NaCl. Growth of the AK13 strain at elevated pH without urea promoted calcium carbonate (CaCO₃) formation. Irregular vaterite-like CaCO₃ minerals that were tightly attached to cells were observed using field-emission scanning electron microscopy. Energy-dispersive X-ray spectrometry, confocal laser scanning microscopy, and X-ray diffraction analyses confirmed the presence of CaCO₃ around the cell. Isotope ration mass spectrometry analysis confirmed that the majority of CO₃^2- ions in the CaCO₃ were produced by cellular respiration rather than being derived from atmospheric carbon dioxide. The minerals produced from calcium acetate-added growth medium formed smaller crystals than those formed in calcium lactate-added medium. Strain AK13 appears to heal cracks on mortar specimens when applied as a pelletized spore powder. Alkaliphilic Bacillus sp. AK13 is a promising candidate for self-healing agents in concrete.

• Journal of Plant Biotechnology
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• 제7권1호
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• pp.67-74
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• 2005

To overcome various disadvantages of conventional cul-ture vessels for micropropagation, a novel disposable vessel, the 'Vitron', made of a multi-layered $OTP^{(R)}$ film and supported by a polypropylene frame, was developed. The film possesses superior properties such as: high light transmittance, low water vapor transmittance and thermal stability and in particular, high gas-permeability. Single nodal explants, which were excised from the multiple shoots derived from shoot-tip culture, were cultured in Vitron and polycarbonate vessels on $3\%$ sugar-containing agar on MS medium and placed at 3000 ppm $CO_2$-enrichment at a low photosynthetic photon flux density (PPFD) ($45{\mu}mol\;m^{-2}\;s^{-1}$). The in vitro and ex vitro growth, and the net photosynthetic rate of in vitro and ex vitro plantlets were significantly enhanced in the Vitron compared to those cultured in a polycarbonate vessel. Explants that were cultured on the same MS medium under low PPFD at various $CO_2$ concentrations were also cultured at 3000 ppm $CO_2$- enrichment at various PPFD: 30, 45, 60, 75 and $90{\mu}mol\;m^{-2}\;s^{-1}$. The best in vitro and ex vitro growth obtained for 3000 ppm $CO_2$-enrichment at $75{\mu}mol\;m^{-2}\;s^{-1}$ PPFD. The novel Vitron vessel, when placed under the two conditions, may replace conventional culture vessels for the successful micropropagation of sweetpotato.

• Asian Journal of Atmospheric Environment
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• 제12권1호
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• pp.1-16
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• 2018

Ground-level ozone ($O_3$) can be a menace for vegetation, especially in Asia where $O_3$ levels have been dramatically increased over the past decades. To ensure food security and maintain forest ecosystem services, such as nutrient cycling, carbon sequestration and functional diversity of soil biota, in the over-populated Asia, environmental standards are needed. To set proper standards, dose-response relationships should be established from which critical levels are derived. The predictor of the response in the dose-response relationship is an $O_3$ metric that indicates the dose level to which the plant has been exposed. This study aimed to review the relevant scientific literature and summarize the $O_3$ metrics used worldwide to provide insights for Asia. A variety of $O_3$ metrics have been used, for which we discuss their strengths and weaknesses. The most widely used metrics are based only on $O_3$ levels. Such metrics have been adopted by several regulatory agencies in the global. However, they are biologically irrelevant because they ignore the plant physiological capacity. Adopting AOT40 ($O_3$ mixing ratios Accumulated Over the Threshold of $40nmol\;mol^{-1}$) as the default index for setting critical levels in Asia would be a poor policy with severe consequences at national and Pan-Asian level. Asian studies should focus on flux-based $O_3$ metrics to provide relevant bases for developing proper standards. However, given the technical requirements in calculating flux-based $O_3$ metrics, which can be an important limitation in developing countries, no-threshold cumulative exposure indices like AOT0 should always accompany flux-based indices.

• 한국조경학회지
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• 제40권5호
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• pp.160-168
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• 2012

본 연구는 직접수확법을 통해 도시 낙엽성 조경수의 탄소저장 및 흡수를 용이하게 추정하는 회귀모델을 제시하고 도시녹지의 탄소저감 계량화에 필요한 기반정보를 구축하였다. 연구대상 수종은 도시조경수로 흔히 식재되는 단풍나무, 느티나무, 왕벚나무 및 은행나무이었다. 수종별로 유목에서 성목에 이르는 일정 간격의 흉고직경 크기를 고려한 수목을 구입하여, 근굴취를 포함하는 직접수확법에 의해 개체당 부위별 및 전체 생체량을 산정하고 탄소저장량을 산출하였다. 또한, 흉고 부위의 수간 원판을 채취하여 직경생장을 분석하고 탄소흡수량을 산정하였다. 흉고직경을 독립변수로 4개 수종별 생장에 따른 단목의 탄소저장 및 흡수를 계량화하는 활용 용이한 회귀모델을 유도하였다. 이들 회귀식의 $r^2$는 0.94~0.99로서 적합도가 상당히 높았다. 단목의 탄소저장량과 탄소흡수량은 모두 직경생장과 더불어 증가하였고, 직경급간 그 차이도 대개 직경이 커질수록 증가하는 경향이었다. 동일 직경에서는 느티나무가 가장 높은 경향이었고, 다음으로 왕벚나무, 은행나무 등의 순이었다. 유도한 회귀식을 적용하면, 흉고직경 15cm인 느티나무 단목은 약 54kg의 탄소를 저장하고 있으며, 연간 7kg의 탄소를 흡수하는 것으로 나타났다. 본 연구는 도시 조경수목의 직접 벌목과 근굴취의 난이성에 기인하여 생체량 확장계수, 지하부/지상부 비율, 직경생장 등 산림수목의 계수를 대용한 기존 연구의 한계성을 극복할 새로운 초석을 마련하였다. 연구결과는 정부나 지자체의 도시녹지 사업과 관련하여 조경수목의 탄소저감을 평가하는 공공기반기술로서 유용하게 활용될 수 있다.