독도에 자생하는 번행초의 뿌리로부터 순수 분리하여 형태적으로 상이한 17개의 내생균류를 선별하였다. 또한 분리된 균류들에 대하여 각각의 염농도와 pH 농도 구배에 따라 생장 시험을 확인하였다. 내생균류에 대해 각각 난장이벼의 유묘에 식물생장활성시험을 진행하였고, 그 결과 YH103 균주가 가장 높은 활성을 나타내었다. 계통분석은 Maximum likelihood 방법을 활용하여 결합된 ITS영역, beta-tubulin 및 calmodulin 유전자 염기서열을 분석하여 분리된 균주의 유연관계를 분석하였다. YH103 균주의 배양여과액을 HPLC와 GC/MS SIM을 이용하여 분석한 결과 식물호르몬인 지베렐린 $GA_4$, $GA_7$, $GA_8$ 및 $GA_{19}$가 확인되었다. 최종적으로 YH103 균주의 형태학적 관찰 및 결합된 유전자 염기서열의 분자적 분석을 통해 GA를 생산하는 새로운 Aspergillus tubingensis로 동정되었다. Coastal plant species Tetragonia tetragonoides (Pall.) Kuntze native to the Dokdo islands was sampled and then 17 endophytic fungi were purely isolated based on morphological differences. The fungal isolates were characterized by their growth properties under NaCl concentration or pH gradient. Culture filtrates of the 17 fungal isolates were treated to Waito-c rice (WR) seedlings for verifying plant growth-promoting activity. As the results, YH103 strain showed the highest plant growth-promoting activity among them. Phylogenetic analysis of the isolates was done by the maximum likelihood method based on partial internal transcribed spacer region (ITS region: contaning ITS1, 5.8S, and ITS2), beta-tubulin (BenA), and calmodulin (CaM) gene sequences. Chromatographic analysis of the strain YH103 culture filtrate showed the existence of gibberellins ($GA_4$, $GA_7$, $GA_8$, and $GA_{19}$). Finally, the strain YH103 was identified as Aspergillus tubingensis by microscopic observation and molecular analysis and, to our knowledge, this is the first report of GAs producing A. tubingensis.
This study was to investigate the effect of salt stress on physiological characteristics such as plant growth, photosynthesis, solutes related to osmoregulation of Beta vulgaris. A significant increase of dry weight was observed in 50 mM and 100 mM NaCl. The contents of Chl a, b and carotenoid were lower in NaCl treatments than the control. On 14 day after NaCl treatment, photosynthetic rate (PN), the transpiration rate (E) and stomatal conductance of CO2 (gs) were reduced by NaCl treatment. On 28 day after NaCl treatment, the significant reduction in gs and E was shown in NaCl 200 mM. However, PN and water use efficiency (WUE) in all NaCl treatments showed higher value than that of control. Total ion contents (TIC) and osmolality were higher than the control. On 14 day after treatment, the contents of proline (Pro) increased significantly in 200 mM and 300 mM NaCl concentration compared with control, whereas on 28 day in all treatments it was lower than that of the control. The contents of glycine betaine (GB) increased with the increase of NaCl concentration. The contents of Na+, Cl-, GB, osmolality and TIC increased with the increase of NaCl concentrations. These results suggested that under severe NaCl stress conditions, NaCl treatment did not induce photochemical inhibition on fluorescence in the leaves of B. vulgaris, but the reduction of chlorophyll contents was related in a decrease in leaf production. Furthermore, increased GB as well as Na+ and Cl- contents resulted in a increase of osmolality, which can help to overcome NaCl stress.
태안반도에 자생하는 해안식물인 해국(Aster sphathulifolius Maxim.), 갯개미취(Aster tripolium L.), 갈대(Phragmites australis), 갯꾸러미풀(Puccinellia nipponica Ohwi) 의 뿌리로부터 총 42주의 내생진균이 분리되었다. 그리고 분리된 내생진균의 ITS지역의 염기서열을 이용하여 동정한 결과 모두 자낭균문에 속하며, 8종류의 목(Botryosphaeriales, Capnodiales, Diaporthales, Dothideales, Eurotiales, Helotiales, Hypocreales, and Pleosporales)과 13종류의 속(Alternaria, Aureobasidium, Cadophora, Cladosporium, Davidiella, Diaporthe, Fusarium, Gibberella, Macrophomina, Metarhizium, Neosartorya, Penicillium, and Phoma)으로 분류되었으며, Eurotiales목의 Penicillium속의 분포비율이 가장 높게 존재하였다. Shannon 다양성지수를 비교한 결과 4종의 해안식물 중 갯개미취에서 분리한 내생진균의 다양성이 가장 높게 확인되었다. Forty-two endophytic fungi were isolated from the roots of coastal plants, such as Aster sphathulifolius Maxim., Aster tripolium L., Phragmites australis, and Puccinellia nipponica Ohwi, naturally growing in Taean peninsula. The identity of the endophytic fungal strains was analyzed using the sequence of internal transcribed spacer regions. All fungi belonged to the phylum Ascomycota, and they were classified into eight orders (Botryosphaeriales, Capnodiales, Diaporthales, Dothideales, Eurotiales, Helotiales, Hypocreales, and Pleosporales) and thirteen genera (Alternaria, Aureobasidium, Cadophora, Cladosporium, Davidiella, Diaporthe, Fusarium, Gibberella, Macrophomina, Metarhizium, Neosartorya, Penicillium, and Phoma). Among the analyzed fungi, the fungi belonging to the genus Penicillium in Eurotiales were the most widely distributed. The host plant Aster tripolium L. was found to contain the most diverse endophytic fungal species among the coastal plants.
본 연구에서는 독도에 자생하는 5종의 식물, 비짜루, 갯괴불주머니, 왕김의 털, 땅채송화, 갯강아지풀을 채집하였다. 독도의 자생식물 뿌리로부터 33 주의 내생진균을 분리하였다. 분리된 모든 내생진균류들은 ITS1, 5.8s와 ITS2를 포함하는 ITS영역의 서열에 의해 분석되었다. 그리고 내생진균류의 배양여과액을 이용하여 난장이벼 유묘에 처리하여 식물생장촉진활성을 확인하였다. 그 결과, 땅채송화로부터 분리된 D-So-1-1 내생진균이 가장 우수한 식물생장촉진활성을 나타내었다. 그리고 분리된 모든 내생진균는 자낭균문의 Eurotiales (86%), Capnodiales (3%), Hypocreales (4%), 및 Incertae sedis (7%)에 속하는 것을 확인하였다. 그리고 내생진균류를 속으로 분류하였을 때, Aspergillus (12%), Cladosporium (3%), Eurotium (3%), Fusarium (18%), Microsphaeropsis (6%), 및 Penicillium (58%)인 것으로 나타났다. In this study, plant samples of five species were collected from the Dokdo islands in South Korea. Plant samples such as Asparagus schoberioides, Corydalis platycarpa, Festuca rubra, Sedum oryzifolium, and Setaria viridis were collected from the Dongdo and Seodo. Endophytic fungal strains were isolated from the roots of five plants from the Dokdo islands. Thirty-three fungal strains were isolated from these native plants. All the endophytic fungi were analyzed by internal transcribed spacer (ITS) sequencing (ITS containing ITS1, 5.8s, and the ITS2 region). Waito-c rice seedlings were treated with fungal culture filtrates to test their plant growth-promoting activity. A bioassay of the D-So-1-1 fungal strain isolated from S. oryzifolium confirmed that it has the highest plant growth-promoting activity. All the endophytic fungi belong to four orders: Eurotiales (86%), Capnodiales (3%), Hypocreales (4%), and Incertae sedis (7%). The endophytic fungi were classified as Ascomycota, which contained Aspergillus (12%), Cladosporium (3%), Eurotium (3%), Fusarium (18%), Microsphaeropsis (6%), and Penicillium (58%) at the genus level.
This study was conducted to determine the extent of drought resistance based on physiological responses of Calystegia soldanella under water deficit. In order to investigate the changes of plant growth, stomatal density, photosynthesis, chlorophyll fluorescence, the contents of chlorophyll and carotenoid, osmolality, total ion contents, the contents of carbohydrate and proline, C. soldanella was grown under well watered and drought stressed conditions for 12 days. In this study, water-deficit resulted in remarkable growth inhibition of C. soldanella. The effect of water-deficit on plant growth was associated with low osmotic potential of soil. On day 12 after drought treatment, dry weight, relative water contents, number and area of leaves and stem length were lower than those of control. The stomatal conductance and net photosynthetic rate were significantly reduced in water stressed plant to regulate inner water contents and $CO_2$ exchange through the stomatal pore. Chlorophyll fluorescence and chlorophyll contents were not different in comparison with the control, indicating that the efficiency of photosystem II was not affected by drought stress. This results could be explained that water-deficit in C. soldanella limits the photosynthetic rate and reduces the plant's ability to convert energy to biomass. A significant increase in total ion contents and osmolality was observed on day 7 and day 12. Accumulation of proline in leaves is associated with the osmotic adjustment in C. soldanella to soil water-deficit. Consequently, this increase in osmolality in water stressed plant can be a result in the increase of ion contents and proline.
Multiple lines of evidence suggest that natural compounds can prevent skin ageing induced by ultraviolet light. Luteolin, a bioactive compound found in chilli, onion, broccoli, celery and carrot, has been reported to exhibit anti-photoageing effects in vitro. However, the molecular targets and mechanisms of luteolin are still poorly understood. In this study, we sought to investigate the effects of luteolin on UVB-induced photoageing and the molecular mechanisms involved, using HaCaT human keratinocytes and SKH-1 hairless mice. Luteolin was found to inhibit UVB-induced MMP-1 expression in HaCaT cells, as well as UVB-induced activation of AP-1, a well-known transcription factor targeting the MMP-1 promoter region, as well as c-Fos and c-Jun, which comprise the AP-1 complex. In contrast, Western blot data showed that UVB-induced phosphorylation of JNK, ERK and p90RSK was not inhibited by luteolin. In vitro kinase assay data revealed that luteolin significantly suppressed JNK1 and p90RSK activity, but not that of JNK2 and ERK2. Pull-down assays showed that luteolin binds JNK1 in an ATP-competitive manner and p90RSK2 in an ATP-independent manner. Luteolin also inhibited UVB-induced wrinkle formation and MMP-13 expression, a rodent interstitial collagenase in mouse skin, in vivo. Taken together, our observations suggest that luteolin exhibits anti-photoageing effects in vitro and in vivo and may have potential as a treatment for the prevention of skin ageing.
Nonmelanoma skin cancer is one of the most frequently occurring cancers in the United States. Chronic exposure to UVB irradiation is a major cause of this cancer. Daidzein, along with genistein, is a major isoflavone found in soybeans; however, little is known about the chemopreventive effects of daidzein and its metabolites in UVB-induced skin cancer. Here, we found that 7,3′,4′-trihydroxyisoflavone (THIF), a major metabolite of daidzein, effectively inhibits UVB-induced cyclooxygenase 2 (COX-2) expression through the inhibition of NF-κB transcription activity in mouse skin epidermal JB6 P+ cells. In contrast, daidzein had no effect on COX-2 expression levels. Data from Western blot and kinase assays showed that 7,3′,4′-THIF inhibited Cot and MKK4 activity, thereby suppressing UVB-induced phosphorylation of mitogen-activated protein kinases. Pull-down assays indicated that 7,3′,4′-THIF competed with ATP to inhibit Cot or MKK4 activity. Topical application of 7,3′,4′-THIF clearly suppressed the incidence and multiplicity of UVB-induced tumors in hairless mouse skin. Hairless mouse skin results also showed that 7,3′,4′-THIF inhibits Cot or MKK4 kinase activity directly, resulting in suppressed UVB-induced COX-2 expression. A docking study revealed that 7,3′,4′-THIF, but not daidzein, easily docked to the ATP binding site of Cot and MKK4, which is located between the N- and C-lobes of the kinase domain. Collectively, these results provide insight into the biological actions of 7,3′,4′-THIF, a potential skin cancer chemopreventive agent.
We document the magnetotransport properties of multicomponent La0.6Pb0.4Mn0.8Ru0.2O3 oxide thin films deposited using Pulsed Electron Deposition. This is a model composition in this series, which shows adequate hole transport aided by the presence of both Mn4+ and Ru5+ ions with similar t(2g)and e(g) parentage. The optimized metal to insulator transition temperature (T-MIT) of the film has been found to be similar to 298 K and the magnetoresistance (-MR%) ratio of about -65% near the T-MIT was observed for the La0.6Pb0.4Mn0.8Ru0.2O3 thin films. High-Resolution Transmission Electron Microscopy (HRTEM) studies reveal a good epitaxial growth along the (0 0 1) direction on LaAlO3 (LAO) substrate, with the width of the rocking curves (omega scans) < 0.6 degrees.
Chronic exposure to solar ultraviolet (UV) light causes skin photoaging. Many studies have shown that naturally occurring phytochemicals have anti-photoaging effects, but their direct target molecule(s) and mechanism(s) remain unclear. We found that myricetin, a major flavonoid in berries and red wine, inhibited wrinkle formation in mouse skin induced by chronic UVB irradiation (0.18 J/cm2, 3 days/week for 15 weeks). Myricetin treatment reduced UVB-induced epidermal thickening of mouse skin and also suppressed UVB-induced matrix metalloproteinase-9 (MMP-9) protein expression and enzyme activity. Myricetin appeared to exert its anti-aging effects by suppressing UVB-induced Raf kinase activity and subsequent attenuation of UVB-induced phosphorylation of MEK and ERK in mouse skin. In vitro and in vivo pull-down assays revealed that myricetin bound with Raf in an ATP-noncompetitive manner. Overall, these results indicate that myricetin exerts potent anti-photoaging activity by regulating MMP-9 expression through the suppression of Raf kinase activity.
Synthesis of silver and gold nanomaterials in a two-phase system at 30°C using hexadecylamine as both reducing as well as capping agent is discussed. Low amine to metal ratio (1.5) was maintained to understand the effect of amine in the growth and stabilization of nanoparticles. Nanomaterials formation was monitored and characterized by XRD, UV–vis spectroscopy, HRTEM and FT-IR. Formation of silver nanoparticles and subsequent self-organization to form elongated structure was conformed by UV–vis spectra and TEM study. TEM image also supports the formation of elongated structure due to the self-organization of nanoparticles in a secondary process. However, no elongated structure is noticed in case of gold. Gold particles of 4–5nm size are found to aggregates to bigger particles of average size of 12nm through Ostwald ripening process. FT-IR spectra indicate the formation of aliphatic nitriles during silver and gold reduction process. This study indicates that it is difficult to stabilize the smaller nanoparticles after formation with amine to metal ratio of 1.5.
Luteolin, a flavonoid present in various vegetables including onion and broccoli, has been reported to possess anticarcinogenic effects. However, its chemopreventive effect on UV-induced skin cancer and its mechanism are not fully understood. Herein, we examined the chemopreventive effect and associated mechanisms of luteolin in the JB6 P+ cell line and the SKH-1 hairless mouse model. Luteolin suppressed UVB-induced cyclooxygenase-2 expression and activator protein-1 and nuclear factor-kappaB activity in JB6 P+ cells. Immunoblot and kinase assay data showed that luteolin attenuated protein kinase C(epsilon) (PKC(epsilon)) and Src kinase activities and subsequently inhibited UVB-induced phosphorylation of mitogen-activated protein kinases and the Akt signaling pathway. In addition, pull-down assays revealed that luteolin binds directly to PKC(epsilon) and Src in an ATP-competitive manner. Importantly, luteolin suppressed tumor incidence, multiplicity, and overall size in SKH-1 hairless mice. Analysis of the skin by immunohistochemistry and immunoblotting showed that luteolin-treated groups had a substantial reduction in the levels of cyclooxygenase-2, tumor necrosis factor-alpha, and proliferating cell nuclear antigen compared with groups treated with only UVB. Further analysis using skin lysates showed that luteolin inhibited PKC(epsilon) and Src kinase activity. Together, these data suggest that luteolin exerts potent chemopreventive activity against UVB-induced skin cancer mainly by targeting PKC(epsilon)and Src.
We report on the synthesis and characterization of epitaxial c-axis oriented Nb2AlC thin films deposited on c-axis sapphire (Al2O3) substrates by magnetron sputtering. Selected area electron diffraction reveal that independent of substrate temperature or film stoichiometry, there is the growth of a secondary phase not found in bulk, Nb5Al3Cx with a- and c-axis lattice constants of 7.746 angstrom and 5.246 angstrom, respectively. Scanning electron micrographs reveal large surface features, many with hexagonal shape and faceted texture. Atomic force microscopy topographical measurements indicate a surface roughness of approximately 15% of the total film thickness. Electrical transport measurements show typical metal-like conduction with a room temperature resistivity of approximate to 0.9 mu Omega-m and a residual resistivity ratio of 2.5. A superconducting transition was found at approximate to 440 mK. (C) 2009 Elsevier B.V. All rights reserved.
We have investigated structural phase transitions across a ferroelectric-to-antiferroelectric phase boundary in epitaxial (001) oriented Bi(1-x)SmxFeO3 thin films. For the Sm3+ concentration of 0.1 < x < 0.14, we observe short-range antiparallel cation displacements, verified by the appearance of localized 14{011} weak reflections in the selected area electron diffraction patterns. At the critical composition of x=0.14, the system adopts a complex nanoscale domain mixture with appearance of 14{011}, 12{011}, 12{010}, and 12{111} reflections and an incommensurate phase bridging the rhombohedral and orthorhombic phases. For compositions 0.14 < x < 0.2, orientational twin domains coupled with antiphase oxygen octahedral tilts, identified by 12{hkl} weak superstructure are observed. The above systematic changes in the microstructure as a function of Sm3+ doping are linked to the macroscopic functional properties.
We have investigated the single-phase and boiling heat transfer of dielectric liquid under the Reynolds numbers (2000, 3000 and 5000) and under nozzle-plate spacing (H/W; 0.5, 1.0 and 4.0) in a submerged impinging jet system. The boiling incipience increases in proportion to the Reynolds number and in inverse proportion to the nozzle-to-surface spacing. The critical heat flux at H/W=1.0 is lower than those of outer spacings, such as H/W=0.5 and 4.0, due to the characteristics of the jet impingement heat transfer distribution. We suggest a correlation equation of nozzle-plate spacing (H/W) having the lowest CHF for various jet velocities.
We have fabricated exchange-biased Co/Pt layers ((0.3nm/1.5nm)×3) on (001)-oriented Cr2O3 thin films. The multilayered films showed extremely smooth surfaces and interfaces with root mean square roughness of ≈0.3nm for 10μm×10μm area. The Cr2O3 films display sufficient insulation with a relative low leakage current (1.17×10−2A/cm2 at 380MV/m) at room temperature which allowed us to apply electric field as high as 77MV/m. We find that the sign of the exchange bias and the shape of the hysteresis loops of the out-of-plane magnetized Co/Pt layers can be delicately controlled by adjusting the magnetic field cooling process through the Néel temperature of Cr2O3. No clear evidence of the effect of electric field and the electric field cooling was detected on the exchange bias for fields as high as 77MV/m. We place the upper bound of the shift in exchange bias field due to electric field cooling to be 5Oe at 250K.
Wide band gap InGaZn6O9 films of thickness similar to 350 nm were deposited on sapphire (0001) at room temperature by using the pulsed laser deposition technique. The transparent films showed the optical transmission of >80% with the room temperature Hall mobility of similar to 10 cm(2)/V s and conductivity of 4 x 10(2) S/cm at a carrier density >10(20) cm(-3). The electrical properties as a function of deposition temperatures revealed that the conductivity and mobility almost retained up to the deposition temperature of 200 degrees C. The films annealed in different atmospheres suggested oxygen vacancy plays an important role in determining the electrical conductivity of the compound. Room temperature grown heterostructure of n-InGaZn6O9/p-SiC showed a good rectifying behavior with a leakage current density of less than 10(-9) A/cm(2), current rectifying ratio of 10(5) with a forward turn on voltage similar to 3 V, and a breakdown voltage greater than 32 V. (C) 2008 Elsevier B.V. All rights reserved.