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991.
Ito M Matsumuro Y Yamada S Kitamura T Itonori S Sugita M 《Journal of lipid research》2007,48(1):96-103
A novel uronic acid-containing glycosphingolipid (UGL-1) was isolated from the ascidian Halocynthia roretzi. UGL-1 was prepared from chloroform-methanol extracts and purified by the use of successive column chromatography on DEAE-Sephadex, Florisil, and Iatrobeads. Chemical structural analysis was performed using methylation analysis, gas chromatography, gas chromatography-mass spectrometry, matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry, and 1H-NMR spectra. The chemical structure of UGL-1 was determined to be a glucuronic acid-containing glycosphingolipid, Galbeta1-4(Fucalpha1-3)GlcAbeta1-1Cer. The ceramide component was composed of C16:0 and C18:0 acids and C16-, C17-, and C18-phytosphingosines as major components. 相似文献
992.
Here a seedless and template-free technique is demonstrated to scalably grow bismuth nanowires, through thermal evaporation in high vacuum at RT. Conventionally reserved for the fabrication of metal thin films, thermal evaporation deposits bismuth into an array of vertical single crystalline nanowires over a flat thin film of vanadium held at RT, which is freshly deposited by magnetron sputtering or thermal evaporation. By controlling the temperature of the growth substrate the length and width of the nanowires can be tuned over a wide range. Responsible for this novel technique is a previously unknown nanowire growth mechanism that roots in the mild porosity of the vanadium thin film. Infiltrated into the vanadium pores, the bismuth domains (~ 1 nm) carry excessive surface energy that suppresses their melting point and continuously expels them out of the vanadium matrix to form nanowires. This discovery demonstrates the feasibility of scalable vapor phase synthesis of high purity nanomaterials without using any catalysts. 相似文献
993.
994.
995.
The hetero-functionalized macrocyclic complex [CuL2](ClO4)2 bearing one N-CH2C(NH)OMe and one N-CH2CN groups as well as [CuL3](ClO4)2 bearing two N-CH2C(NH)OMe groups have been prepared selectively by the reaction of [CuL1](ClO4)2 (L2 = 2,13-bis(cyanomethyl)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.1.1807.12]docosane) with methanol. The N-CH2C(NH)OCH3 group in [CuL2](ClO4)2 is quite inert against acid hydrolysis. On the other hand, the functional pendant arms in [CuL3](ClO4)2 readily undergo acid hydrolysis. Both [CuL4](ClO4)2 bearing one N-CH2COOCH3 and one N-CH2C(NH)OCH3 groups and [CuL5](ClO4)2 bearing two N-CH2OOCH3 groups have been prepared by the stepwise hydrolysis of [CuL3](ClO4)2. The reactivity of the functional pendant arms in [CuL1](ClO4)2 or [CuL3](ClO4)2 is quite different from that in [NiL1](ClO4)2 or [NiL3](ClO4)2. The crystal structure of [CuL2](ClO4)2 shows that the complex has a slightly distorted square-pyramidal coordination polyhedron with an apical Cu-N (N-CH2C(NH)OCH3 group) bond. The N-CH2C(NH)OCH3 and/or N-CH2COOCH3 groups in [CuL3](ClO4)2, [CuL4](ClO4)2, and [CuL5](ClO4)2 are involved in coordination, and the complexes have distorted trans-octahedral coordination polyhedron. The axial Cu-N (N-CH2C(NH)OCH3 group) distance (2.396(7) Å) of [CuL4](ClO4)2 is considerably longer than the Cu-N (N-CH2C(NH)OCH3 group) distance (2.169(3) Å) of [CuL2](ClO4)2. 相似文献
996.
Joo Mi Jeon Nam Young Ahn Bo Hwa Son Cha Young Kim Chang-deok Han Gun-Do Kim Sang Wan Gal Sung-Ho Lee 《Plant Cell, Tissue and Organ Culture》2007,88(2):225-232
PEG-mediated transformation was used for gene delivery and evaluation of various parameters affecting the transient expression of a gene for ß-glucuronidase (gus) in mesophyll protoplasts of Capsicum annuum. Transient expression was found to be dependent on PEG concentration and exposure time of plasmid DNA to protoplasts as well as the amount of plasmid DNA. Maximum GUS activity was obtained when protoplasts were applied to 40% concentration and molecular weight was 6,000 of PEG solution with 30 min of exposure time. Protoplasts of pepper were transformed with a vector, pCAMBIA::Ac, which contained a pCAMBIA1302 T-DNA vector carrying a maize transposable element, Ac (activator), a selection marker HPT (hygromycin phosphotransferase), and a GFP-coding region driven by the 35S promoter in the presence of PEG. Approximately 30% of the protoplasts expressed GFP. Visibly transformed colonies were obtained from protoplasts after 2 months of culture and GFP was expressed. Southern hybridization confirmed the presence of Ac in the pepper genome. 相似文献
997.
Activation of Endogenous Antioxidant Defenses in Neuronal Cells Prevents Free Radical-Mediated Damage 总被引:3,自引:4,他引:3
Abstract: Dopamine (DA) is oxidized to the neurotoxic prooxidant species H2 O2 , OH• , and DA quinones. We tested whether dimethyl fumarate (DMF), an electrophile shown to induce a pleiotropic antioxidant response in nonneuronal cells, could reduce the toxicity of DA metabolites in neural cells. Treatment of the N18-RE-105 neuroblastoma-retina hybridoma cell line with 30–150 µ M dopamine led to cell death within 24 h, which increased steeply with dose, decreased with higher plating density, and was blocked by the H2 O2 -metabolizing enzyme catalase. Pretreatment with DMF (30 µ M , 24 h) significantly attenuated DA and H2 O2 toxicity (40–60%) but not that caused by the calcium ionophore ionomycin. DMF treatment also elevated total intracellular GSH and increased activities of the antioxidant enzymes quinone reductase (QR), glutathione S -transferase (GST), glutathione reductase, and the pentose phosphate enzyme glucose-6-phosphate dehydrogenase. To assess the protective efficacy of QR and GST, a stable cell line was constructed in which these enzymes were overexpressed. Cell death in the overexpressing line was not significantly different from that in a cell line expressing normal QR and GST activities, indicating that these two enzymes alone are insufficient for protection against DA toxicity. Although the relative importance of a single antioxidant enzyme such as QR or GST may be small, antioxidant inducers such as DMF may prove valuable as agents that elicit a broad-spectrum neuroprotective response. 相似文献
998.
Introduction of tyramide signal amplification (TSA) to pre-embedding nanogold-silver staining at the electron microscopic level. 总被引:3,自引:0,他引:3
Seung-won Lee Song Eun Lee Seong Hyuk Ko Eun Kyoung Hong Kwang Il Nam Kei-ichiro Nakamura Shuhei Imayama Yeong-Joon Park Kyu Youn Ahn Choon Sang Bae Baik Yoon Kim Sung Sik Park 《The journal of histochemistry and cytochemistry》2005,53(2):249-252
The tyramide signal amplification (TSA) technique has been shown to detect scarce tissue antigens in light and electron microscopy. In this study we applied the TSA technique at the electron microscopic level to pre-embedding immunocytochemistry. This protocol was compared to the non-amplified protocol. With the TSA protocol, the labeling of GM130, a cis-Golgi matrix protein, was tested in a cell line and found to be highly sensitive and more enhanced than that with the simple protocol. Moreover, the gold particles were well localized to the cis-side of the Golgi apparatus in both the TSA and the simple protocol. 相似文献
999.
Hyung W. Nam Caleb A. Grant Ashton N. Jorgensen Carrie J. Holtz‐Heppelmann Marjan Trutschl Urska Cvek 《Proteomics》2020,20(1)
Dysfunction of glutamate neurotransmission in the nucleus accumbens (NAc) has been implicated in the pathophysiology of alcohol use disorders (AUD). Neurogranin (Ng) is exclusively expressed in the brain and mediates N‐methyl‐d ‐aspartate receptor (NMDAR) hypo‐function by regulating the intracellular calcium‐calmodulin (Ca2+‐CaM) pathway. Ng null mice (Ng–/– mice) demonstrate increased alcohol drinking compared to wild‐type mice, while also showing less tolerance to the effect of alcohol. To identify the molecular mechanism related to alcohol seeking, both in vivo microdialysis and label‐free quantification proteomics comparing Ng genotype and effects of alcohol treatment on the NAc are utilized. There is significant difference in glutamate and gamma‐aminobutyric acid (GABA) neurotransmission between genotypes; however, alcohol administration normalizes both glutamate and GABA levels in the NAc. Using label‐free proteomics, 427 protein expression changes are identified against alcohol treatment in the NAc among 4347 total proteins detected. Bioinformatics analyses reveal significant molecular differences in Ng null mice in response to acute alcohol treatment. Ingenuity pathway analysis found that the AKT network is altered significantly between genotypes, which may increase the sensitivity of alcohol in Ng null mice. The pharmacoproteomics results presented here illustrate a possible molecular basis of the alcohol sensitivity through Ng signaling in the NAc. 相似文献
1000.
Jun-Young Kim Sina Henrichs Aurélien Bailly Vincent Vincenzetti Valpuri Sovero Stefano Mancuso Stephan Pollmann Daehwang Kim Markus Geisler Hong-Gil Nam 《The Journal of biological chemistry》2010,285(30):23309-23317
Plant development and physiology are widely determined by the polar transport of the signaling molecule auxin. This process is controlled on the cellular efflux level catalyzed by members of the PIN (pin-formed) and ABCB (ATP-binding cassette protein subfamily B)/P-glycoprotein family that can function independently and coordinately. In this study, we have identified by means of chemical genomics a novel auxin transport inhibitor (ATI), BUM (2-[4-(diethylamino)-2-hydroxybenzoyl]benzoic acid), that efficiently blocks auxin-regulated plant physiology and development. In many respects, BUM resembles the functionality of the diagnostic ATI, 1-N-naphtylphtalamic acid (NPA), but it has an IC50 value that is roughly a factor 30 lower. Physiological analysis and binding assays identified ABCBs, primarily ABCB1, as key targets of BUM and NPA, whereas PIN proteins are apparently not directly affected. BUM is complementary to NPA by having distinct ABCB target spectra and impacts on basipetal polar auxin transport in the shoot and root. In comparison with the recently identified ATI, gravacin, it lacks interference with ABCB membrane trafficking. Individual modes or targets of action compared with NPA are reflected by apically shifted root influx maxima that might be the result of altered BUM binding preferences or affinities to the ABCB nucleotide binding folds. This qualifies BUM as a valuable tool for auxin research, allowing differentiation between ABCB- and PIN-mediated efflux systems. Besides its obvious application as a powerful weed herbicide, BUM is a bona fide human ABCB inhibitor with the potential to restrict multidrug resistance during chemotherapy. 相似文献