摘要：
A simple, selective, highly sensitive, and label-free electrochemical immunosensor for atrazine detection was developed by immobilizing gold nanoparticles (GNPs) on the gold electrode surface. The modified gold electrode exhibited good electrochemical activity. The high sensitive detection was achieved by increased the surface area of work electrode resulting in capturing more anti-atrazine monoclonal antibodies. The whole immunosensor fabrication process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with the use of ferricyanide as an electrochemical redox indicator, respectively. The signal was triggered based on the interaction between anti-atrazine monoclonal antibody and atrazine via differential pulse voltammetry (DPV). Under the optimal conditions, a limit of detection for atrazine as low as 0.016 ng/mL was obtained in buffer, and the linear working range was between 0.05 ng/mL and 0.5 ng/mL. The recovery of 95.5-119.8% was obtained in maize. The proposed immunosensor has acceptable stability and reproducibility, thus could be applied to other pesticides analysis of crop samples in practice. (C) 2013 Elsevier B.V. All rights reserved.
作者：
Shi, Xingbo;Tu, Yang;Liu, Xiaojun;Yeung, Edward S.;Gai, Hongwei*
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2013年15(9):3130-3132 ISSN：1463-9076
通讯作者：
Gai, Hongwei
作者机构：
[Shi, Xingbo] Hunan Agr Univ, Coll Food Sci & Technol, Changsha 410128, Hunan, Peoples R China.;[Gai, Hongwei; Liu, Xiaojun; Tu, Yang] Jiangsu Normal Univ, Sch Chem & Chem Engn, Xuzhou 221116, Jiangsu, Peoples R China.;[Gai, Hongwei; Liu, Xiaojun; Tu, Yang] Jiangsu Normal Univ, Jiangsu Key Lab Green Synthet Chem Funct Mat, Xuzhou 221116, Jiangsu, Peoples R China.;[Yeung, Edward S.] Hunan Univ, Sch Biol, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Gai, Hongwei] J;Jiangsu Normal Univ, Sch Chem & Chem Engn, Xuzhou 221116, Jiangsu, Peoples R China.
摘要：
Core-shell quantum dots suffer from photobleaching by light at wavelengths longer than their emission wavelengths. That is, QD photobleaching can be triggered by photons with low energies that are insufficient to pump electrons into the conduction band. The most probable reason is that electrons are pumped into a surface state and then nonradiatively decayed as in conventional photobleaching.
期刊：
Journal of Medicinal Plants Research,2011年5(17):4298-4303 ISSN：1996-0875
通讯作者：
Lin, Qinlu
作者机构：
[Xiao, Huaxi; Wu, Yue; Wu, Wei; Fu, Xiangjin; Liu, Gao-Qiang; Lin, Qinlu] Cent S Univ Forestry & Technol, Natl Engn Lab Rice & By Prod Further Proc, Changsha 410004, Hunan, Peoples R China.;[Xiao, Huaxi; Fu, Xiangjin; Liu, Gao-Qiang; Lin, Qinlu] Cent S Univ Forestry & Technol, Coll Life Sci & Technol, Hunan Prov Key Lab Forestry Biotechnol, Changsha 410004, Hunan, Peoples R China.;[Tian, Wei] Hunan Agr Univ, Dept Food Sci & Technol, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Lin, Qinlu] C;Cent S Univ Forestry & Technol, Natl Engn Lab Rice & By Prod Further Proc, Changsha 410004, Hunan, Peoples R China.
关键词：
Green tea polyphenols;rice starch;gelatinization;retrogradation;differential scanning calorimetry;X-ray diffraction
摘要：
The effect of green tea polyphenols (GTP) on the property of rice starch was investigated. 0, 5, 10 and 15% of GTP (based on rice starch weight) was added to rice starches with high (HAC), intermediate (IAC) and low (LAC) amylose contents, respectively. The gelatinization and retrogradation properties of rice starches with different amylose content containing different levels of GTP were analyzed by differential scanning calorimetry (DSC). The results exhibited that GTP could retard retrogradation of the three rice starches, which was further proved by X-ray diffraction investigation. In the DSC analysis, the temperature and enthalpy of starches gelatinization decreased with the concentration of GTP increasing. After storage at 4 degrees C for 20 days, retrogradation enthalpy (Delta H-ret) for all rice starches with different levels GTP began to appear, and the Delta H-ret and degree of retrogradation (DR%) of the three rice starches significantly decreased with the increased level of GTP. The X-ray diffractogram indicate that all the three gelatinized rice starch gels showed B-type X-ray diffraction patterns, and the B-type X-ray diffraction patterns gradually disappeared with the concentration of GTP increasing.
摘要：
The physical and chemical properties of the flours, starches, and modified starches of indica rice and japonica rice were investigated in this paper. Results showed that the swelling powers of flour, starch, and phosphate starch [substitution degree (DS)=0.065] of japonica rice were significantly higher than those (DS=0.065) of indica rice. The transmittance of modified starches was highest; and that of flours was lowest. The pasting property investigated with rapid visco analyzer (RVA) indicated that the peak viscosity and breakdown value of paste with high swelling power were high. Furthermore, the effect of protein and amylose content on pasting property were investigated. The results of rheological properties determined using rheological rheometer showed that at the same temperature, the storage modulus (G') of flour, starch, and modified starch of indica rice was higher than that of japonica rice. For each variety, the G' of flour was the highest, while the G' of modified starch was the lowest.
关键词：
Anthraquinone;Debaryomyces hansenii;Denaturing gradient gel electrophoresis;Eurotium cristatum;Fungal community;Fuzhuan brick-tea
摘要：
Chinese Fuzhuan brick-tea is a unique microbial fermented tea characterized by a period of fungal growth during its manufacturing process. The aim of the present study was to characterize, both physicochemically and microbiologically, traditional industrial production processes of Fuzhuan brick-tea. Fermenting tea samples were collected from the largest manufacturer. Physicochemical analyses showed that the low water content in the tea substrates provided optimal growth conditions for xerophilic fungi. The fungal communities existing in tea materials, fermenting tea, and stored teas were monitored by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) targeting the D1 region of the 265 rRNA genes, followed by sequencing of the amplicons. Results revealed that the microorganisms were from, or closely related to, the genera Eurotium, Debaryomyces, Aspergillus, Verticillium, Pichia, Pestalotiopsis, Rhizomucor and Beauveria. This is the first report of Debaryomyces participating in the processing of Fuzhuan brick-tea. We concluded that the dominant genera Eurotium, Debaryomyces and Aspergillus are beneficial fungi associated with the fermentation of Fuzhuan brick-tea. The genus Beauveria was present in the stored Fuzhuan brick-tea, which may help protect tea products from insect spoilage. The remaining four genera were of minor importance in the manufacturing of Fuzhuan brick-tea. The predominant Eurotium species, a strain named Eurotium sp. FZ, was phenotypically and genotypically identified as Eurotium cristatum. High performance thin layer chromatography analysis of anthraquinones showed that emodin existed in all the dark tea samples, but physcion was only detectable in the tea fermented by E. cristatum. The PCR-DGGE approach was an effective and convenient means for profiling the fungal communities in Fuzhuan brick-tea. These results may help promote the use of microbial consortia as starter cultures to stabilize and improve the quality of Fuzhuan brick-tea products. (C) 2011 Elsevier B.V. All rights reserved.
摘要：
Hexavalent chromium (Cr(VI)), a commonly used industrial metal, is a well-known mutagen and carcinogen, and occupational exposure can induce a broad spectrum of adverse health effects, including cancers. Although Cr(VI)-induced DNA damage is thought to be the primary mechanism of chromate genotoxicity and mutagenicity, there is an increasing number of reports showing that epigenetic mechanisms of gene regulation might be a central target of Cr(VI) toxicity. Epigenetic changes, such as changes in phosphorylation, altered DNA methylation status, histone acetylation and signaling pathways, have been observed after chromium exposure. Nevertheless, to better demonstrate the roles of epigenetic modifications in Cr(VI)-induced carcinogenesis, more work needs to be carried out. This study is aimed to investigate changes in biotinidase (BTD) and holocarboxylase synthetase (HCS), two major proteins which maintain homeostasis of the newfound epigenetic modification: histone biotinylation, in cells exposed to Cr(VI). The data showed that Cr(VI) decreased BID expression at the transcriptional level in human bronchial epithelial cells (16HBE). In addition, using the epigenetic modifiers, 5-Aza-2'-deoxycytidine (Aza) and Trichostatin A (TSA), we found that modifications of histone acetylation reversed the inhibition of BID, suggesting that Cr(VI) may cause down regulation of BID by modifications of histone acetylation. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
作者机构：
[Li, Qingjie] Univ Texas Med Branch Galveston, Div Gastroenterol, Dept Internal Med, Galveston, TX 77550 USA.;[Loehr, Christiane V.] Oregon State Univ, Coll Vet Med, Corvallis, OR 97331 USA.;[Dashwood, Roderick H.] Oregon State Univ, Linus Pauling Inst, Corvallis, OR 97331 USA.;[Dashwood, Roderick H.] Oregon State Univ, Dept Environm & Mol Toxicol, Corvallis, OR 97331 USA.;[Luo, Cunhui] Hunan Agr Univ, Coll Food Sci & Technol, Changsha, Hunan, Peoples R China.
通讯机构：
[Li, Qingjie] U;Univ Texas Med Branch Galveston, Div Gastroenterol, Dept Internal Med, Galveston, TX 77550 USA.
关键词：
activator protein-1;activator protein AP-2;GATA4 transcription factor;liver;protein kinase A
摘要：
Aim: Activator protein 2 alpha (AP-2 alpha) belongs to the AP-2 family of transcription factors that are involved in the regulation of cell proliferation, differentiation, apoptosis and carcinogenesis and has been suggested to function as a tumor suppressor in many cancers. However, the physiological role of AP-2 alpha in hepatocytes is unknown. The present study is to characterize the expression and function of AP-2 alpha in the liver of conscience mouse. Methods: Exogenous AP-2 alpha was overexpressed in the mouse liver by in vivo gene delivery and changes in transcription factor expression were identified by using protein-DNA arrays and immunoblotting. Results: Western blotting and protein/DNA arrays showed that AP-2 alpha is expressed in the nuclei of mouse hepatocytes. Overexpression of AP-2 alpha in vivo significantly suppressed transcription factors AP-1, CREB and c-Myc, and markedly increased CBF, c-Myb, NF-1, Pax-5, RXR, Smad3/4, TR(DR-4), USF-1 and GATA. Among all GATA proteins, only GATA-4 level was dramatically elevated and there was a concomitant loss of phospho-GATA-4. Corresponding changes were detected in upstream kinases Akt, GSK-3 beta and PKA, which regulates the phosphorylation status and stability of GATA-4 protein. Conclusions: AP-2 alpha is expressed in mouse hepatocytes and it acts as a master regulator of numerous transcription factors in the liver.
摘要：
The chlorogenic acids of Gardeniae Fructus used traditionally as a Chinese herbal medicine (zhizi) have been investigated qualitatively by liquid chromatography/multi-stage mass spectrometry (LC/MS4). Twenty-nine chlorogenic acids were detected and twenty-five characterised to regioisomer level on the basis of their fragmentation, twenty-four for the first time from this source. Assignment to the level of individual regioisomers was possible for three caffeoylquinic acids, three dicaffeoylquinic acids, three sinapoylquinic acids, four caffeoyl-sinapoylquinic acids, two feruloyl-sinapoylquinic acids, one p-coumaroyl-sinapoylquinic acid, three (3-hydroxy, 3-methyl)glutaroyl-quinic acids, two (3-hydroxy, 3-methyl)glutaroyl-feruloylquinic acids, one (3-hydroxy, 3-methyl)glutaroyl-dicaffeoylquinic acid, and one (3-hydroxy, 3-methynglutaroyl-caffeoyl-feruloylquinic acid. Six (3-hydroxy, 3-methyl)glutaroyl-caffeoylquinic acids were detected and two were tentatively assigned as 3-caffeoyl-4-(3-hydroxy, 3-methyl)glutaroylquinic acid and 3-caffeoyl-5-(3-hydroxy, 3-methyl)glutaroylquinic acid. The (3-hydroxy, 3-methyl)glutaroyl residue modifies the mass spectral fragmentation behavior and elution sequence compared with the chlorogenic acids that contain only a cinnamic acid residue(s). Fourteen of these twenty-nine chlorogenic acids have not previously been reported from any source. Copyright (C) 2010 John Wiley & Sons, Ltd.
通讯机构：
[Xiao, HB ] ;Hunan Agr Univ, Coll Vet Med, Changsha 410128, Hunan, Peoples R China.
关键词：
6-tetrahydroxyxanthone;angiopoietin-like protein3;lipoprotein lipase;total cholesterol;triglyceride;high-density lipoprotein cholesterol;apolipoproteinE-deficient mice;6-tétrahydroxyxanthone;protéine de type angiopoïétine 3;lipoprotéine lipase;cholestérol total;triglycéride;cholestérol de la lipoprotéine de haute densité;souris déficientes en apolipoprotéine E
