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Find video protocols related to scientific articles indexed in Pubmed.
Investigation of the chemical compositions in tobacco of different origins and maturities at harvest by GC-MS and HPLC-PDA-QTOF-MS.
J. Agric. Food Chem.
PUBLISHED: 05-23-2014
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Tobacco samples of a same cultivar grown in different plantations in China were evaluated for their chemical compositions at different maturities for the first time. This was accomplished by a comprehensive and reliable method using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry (HPLC-PDA-QTOF-MS) to analyze the fat-soluble and polar components in 12 batches of tobacco samples of three origins and four maturities. The GC-MS analyses showed that tobacco samples harvested at 40 days after transplantation exhibited more fat-soluble components, while those harvested at 100 days after transplantation exhibited the least fat-soluble components. Tentatively, identification of the main components as well as quantitative analyses of eight reference compounds, including five alkaloids, two polyphenols, and a coumarin, was performed by the developed HPLC-QTOF-PDA method. Results showed significant differences among origins and maturities in the contents of these compounds. The nicotine contents showed great variety among the 12 tobacco samples. The highest nicotine content were found in a sample from Zhengzhou harvested at 40 days after transplantation (ZZ-T with 25399.39 ± 308.95 ?g/g), and the lowest nicotine level was detected in a sample from Zunyi harvested at 60 days after transplantation (ZY-X with 1654.49 ± 34.52 ?g/g). The highest level of rutin was found in a Jiangchuan sample harvested at 60 days after transplantation (JC-X with 725.93 ± 40.70 ?g/g), and the lowest rutin content was detected in a Zunyi tobacco sample harvested at 60 days after transplantation (ZY-X with 87.42 ± 2.78 ?g/g). The developed method provided a convenient approach which might be applied for rapid maturity evaluation and tobacco flavor identification and also holds the potential for analysis of compounds present in other plants.
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Serum amyloid A and clusterin as potential predictive biomarkers for severe hand, foot and mouth disease by 2D-DIGE proteomics analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Hand, foot, and mouth disease (HFMD) affects more than one million children, is responsible for several hundred child deaths every year in China and is the cause of widespread concerns in society. Only a small fraction of HFMD cases will develop further into severe HFMD with neurologic complications. A timely and accurate diagnosis of severe HFMD is essential for assessing the risk of progression and planning the appropriate treatment. Human serum can reflect the physiological or pathological states, which is expected to be an excellent source of disease-specific biomarkers. In the present study, a comparative serological proteome analysis between severe HFMD patients and healthy controls was performed via a two-dimensional difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) strategy. Fifteen proteins were identified as differentially expressed in the sera of the severe HFMD patients compared with the controls. The identified proteins were classified into different groups according to their molecular functions, biological processes, protein classes and physiological pathways by bioinformatics analysis. The up-regulations of two identified proteins, serum amyloid A (SAA) and clusterin (CLU), were confirmed in the sera of the HFMD patients by ELISA assay. This study not only increases our background knowledge about and scientific insight into the mechanisms of HFMD, but also reveals novel potential biomarkers for the clinical diagnosis of severe HFMD.
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Toxicity of raw and processed roots of Polygonum multiflorum.
Fitoterapia
PUBLISHED: 09-30-2011
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The roots of Polygonum multiflorum (Chinese name: He-Shou-Wu, HSW) are used in traditional Chinese medicine for many diseases in processed form or raw state. There are reports dealing with the toxicity of HSW. However, the toxicity is caused by over dosage or by the herb itself remains unclear. We evaluated the toxicity of raw and processed HSW on Kunming (KM) mice. For raw HSW, the toxicity of water decocta is much higher than that of acetone extract. Meanwhile, the toxicity of acetone extract of raw HSW is considerably higher than that of acetone extract of processed HSW. HPLC analyses revealed that the contents of characteristic compounds in raw HSW were changed after processing: the content of 2,3,4,5-tetrahydroxystilbene 2-O-?-D-glucoside was decreased by 55.8%, whereas the content of emodin was increased by 34.0%. Thus, processing could reduce the toxicity of HSW. Thus, the toxicity of HSW does not depend on the content of anthranoid derivatives, it may be correlated with the content of tetrahydroxystilbene glucosides.
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[GC-MS analysis of volatile oils from fresh and processed typhonii rhizoma].
Zhongguo Zhong Yao Za Zhi
PUBLISHED: 08-16-2011
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Typhonii Rhizoma is a toxic traditional Chinese medicine. Its toxic components remained unclear. To compare chemical composition of volatile oils from fresh and processed Typhonii Rhizoma qualitatively, volatile oils were obtained by stream distillation and analyzed by GC-MS. The data obtained from GC-MS were processed by principal component analysis. From the essential oils of fresh and processed Typhonii Rhizoma, 43 compounds and 34 compounds were identified respectively. The chemical composition and content in the two oils was different. In the two essential oils 15 identical components were detected. The chemical components and their contents in the essential oils are changing with the storage.
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Facile synthesis of near-monodisperse Ag@Ni core-shell nanoparticles and their application for catalytic generation of hydrogen.
Nanotechnology
PUBLISHED: 03-23-2011
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Magnetically recyclable Ag-Ni core-shell nanoparticles have been fabricated via a simple one-pot synthetic route using oleylamine both as solvent and reducing agent and triphenylphosphine as a surfactant. As characterized by transmission electron microscopy (TEM), the as-synthesized Ag-Ni core-shell nanoparticles exhibit a very narrow size distribution with a typical size of 14.9 ± 1.2 nm and a tunable shell thickness. UV-vis absorption spectroscopy study shows that the formation of a Ni shell on Ag core can damp the surface plasmon resonance (SPR) of the Ag core and lead to a red-shifted SPR absorption peak. Magnetic measurement indicates that all the as-synthesized Ag-Ni core-shell nanoparticles are superparamagnetic at room temperature, and their blocking temperatures can be controlled by modulating the shell thickness. The as-synthesized Ag-Ni core-shell nanoparticles exhibit excellent catalytic properties for the generation of H(2) from dehydrogenation of sodium borohydride in aqueous solutions. The hydrogen generation rate of Ag-Ni core-shell nanoparticles is found to be much higher than that of Ag and Ni nanoparticles of a similar size, and the calculated activation energy for hydrogen generation is lower than that of many bimetallic catalysts. The strategy employed here can also be extended to other noble-magnetic metal systems.
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[Establishment of a multiplex PCR detection method for four foodborne pathogens].
Wei Sheng Yan Jiu
PUBLISHED: 03-09-2011
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To establish a multiplex PCR method for simultaneous detection of Salmonella, Shigella, Staphylococcus aureus and Listeria monocytogenes in food.
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[The effects of hypokalemia on the Na+ channel in cardiac tissue--a computer simulation study].
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi
PUBLISHED: 04-02-2009
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In order to explore the reason why hypokalemia could increase the vulnerable window (VW) for unidirectional conduction block in Long QT Syndromes (LQTS), we observed the effect of hypokalemia on the spatial gradients of Na channel conductance (G(Na)) and gating factors by using the LR91 1-dimensional heterogeneous virtual cardiac ventricular tissue model quatitively. The computer simulation experiments were divided into two groups, namely control and LQTS groups. The action potential was elicited after the basic stimulus S1 (-70 microA/microF, 1.5 ms) was given 10 times with basic cycle length (BCL) 500, 1000 and 2000 ms. To test the VW in unit of time (VWtime), the S1-S2 programmed stimuli were used with shortening S1S2 interval at the decrement of 1 ms. At the same time, the spatial gradients of Na channel conductance (G(Na)) and gating factors, m, h, j, were investigated. The APD and ionic channel currents were also detected under the conditions of normal and lower concentration of K+ outside of cell. We found that hypokalemia, LQTS and slow pacing rate enhanced the spatial gradient of G(Na) by increasing the spatial gradient of inactive gating factors h x j. The results also showed that hypokalemia deduced the peak values of I(K) and I(K1), which prolonged the action potential duration and enlarged the repolarization dispersion in this 1-D tissue cable model. Possibly these are the important factors to cause the spatial gradient of h x j and G(Na). enlargement. These changes increase the incidence of unidirectional conduction block of VW, and are vital reasons to increase the possibility of ventricular arrhythmia generation.
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[Determination of ten basic dyes in meat products by ultra fast liquid chromatography-ion trap time of flight mass spectrometry].
Se Pu
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A method was developed for the simultaneous determination of 10 basic dyes in meat products using ultra fast liquid chromatography-ion trap time of flight mass spectrometry (LC-IT-TOF-MS). The target analytes were separated at a flow rate of 0.2 mL/min on a Waters Acquity UPLC BEH C18 (100 mm x 2.1 mm, 1.7 microm) column with a gradient elution. The mobile phase was 5 mmol/L ammonium acetate-acetonitrile (containing 0.1% (v/v) formic acid). The identification and quantification were achieved in positive ion mode with electro spray ionization source. The samples were extracted with a simple procedure using acetonitrile and cleaned up by weak cation exchange (Oasis WCX) solid phase extraction column. Ten basic dyes were determined by LC-IT-TOF-MS, and quantified by external standard method. The developed method showed a good linearity over the wide range of 1.0 - 100.0 microg/L, and the relative standard deviations (n = 7) were less than 8.54%. The average recoveries of the ten basic dyes at three levels (2, 10 and 25 microg/kg) were ranged from 65.39% to 119.18%. Therefore, this method, owing to its simplicity, rapidity and high sensitivity, has a good applicability to the simultaneous determination of dye residues in meat products.
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A new hepatotoxic triterpenoid ketone from Curculigo orchioides.
Fitoterapia
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To investigate hepatotoxic constituents, a new cycloartane-type triterpenoid ketone together with four known components was isolated from rhizomes of Curculigo orchioides. The structures of five compounds were elucidated on the basis of spectroscopic methods, including 1D and 2D NMR, and single-crystal X-ray diffraction analysis. Their hepatotoxicity effects in human hepatic cell line HL-7702 were tested for the first time.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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