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Deng S.,Rockefeller University | Deng S.,Sun Yat Sen University | Xu J.,Rockefeller University | Xu J.,Wilmar Biotechnology Research and Development Center Shanghai Co. | And 6 more authors.
Plant Journal | Year: 2015

Transposable elements (TEs) and repetitive sequences are ubiquitously present in eukaryotic genomes which are in general epigenetically silenced by DNA methylation and/or histone 3 lysine 9 methylation (H3K9me). RNA-directed DNA methylation (RdDM) is the major pathway that initiates de novo DNA methylation in Arabidopsis and sets up a self-reinforcing silencing loop between DNA methylation and H3K9me. However, a key issue is the requirement of a basal level transcript from the target loci to initiate the RNA-based silencing. How the heterochromatic silenced loci are transcribed remains largely unknown. Here, we show that JMJ24, a JmjC domain-containing protein counteracts H3K9me to promote basal level transcription of endogenous silenced loci in Arabidopsis. JMJ24 functionally resembles the fission yeast JmjC protein Epe1. The transcript promoted by JMJ24 is, at least in part, processed to small RNA to initiate the RdDM. Genome-wide transcriptome profiling indicates that transcript levels of TEs are more likely regulated by JMJ24, compared with protein-coding genes. Our data suggest that JMJ24 plays a conserved role in promoting basal level transcription of endogenous silenced loci to reinforce the silencing. We also provide evidence of a physical association between JMJ24 and RNA-dependent RNA polymerase 2 (RDR2), which represents an evolved property of the RNA silencing pathway. Significance Statement We reported here that JMJ24 physically interacts with RDR2 and is required for the basal level transcription of endogenous silenced loci to initiate the RdDM of target gene in Arabidopsis. Our results suggest JmjC-domain containing protein plays a conserved role in promoting the transcription of heterochromatic silenced loci to reinforce silencing state. © 2015 The Authors. © 2015 John Wiley & Sons Ltd.


Zhang Z.,Shanghai JiaoTong University | Gao B.,Shanghai JiaoTong University | Gao B.,University of Maryland University College | Zhang X.,Shanghai JiaoTong University | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015

This study investigated whether and how triacylglycerol (TAG) may serve as a precursor for 3-monochloro-1,2-propanediol (3-MCPD) fatty acid ester formation using tristearoylglycerol (TSG). TSG was reacted with inorganic chloride compounds including NaCl, KCl, FeCl2, CuCl2, ZnCl2, FeCl3 and dry HCl, or organic chlorine compound lindane at different temperatures. Only FeCl2 and FeCl3 were able to form 3-MCPD esters from TSG. Further electron spin resonance (ESR) determination of TSG, Fe2(SO4)3 and 5,5-dimethylpyrroline-N-oxide (DMPO) reactions revealed potential of Fe ion in promoting free radical generations under the experimental conditions. To further confirm the effect of Fe ion, chelating agent (EDTA-2Na) was added to the model reactions. The results showed for the first time that EDTA-2Na was able to reduce the generation of 3-MCPD esters. In addition, FT-IR examination indicated a possible involvement of a carbonyl group during the reaction. Taking all the observations together, the possible mechanisms, involving the formation of either a cyclic acyloxonium or a glycidol ester radical intermediate, were proposed for generating 3-MCPD fatty acid di- and mono- esters from TAG under a high temperature and low moisture condition, as well as the coformation of glycidol esters. The results from this study may be useful for reducing the level of 3-MCPD esters and related toxicants in the refined edible oils and food products. © 2015 American Chemical Society.


Liu M.,Shanghai JiaoTong University | Gao B.-Y.,Shanghai JiaoTong University | Qin F.,Shanghai JiaoTong University | Wu P.-P.,Shanghai JiaoTong University | And 7 more authors.
Food and Chemical Toxicology | Year: 2012

The acute oral toxicity of 1-palmitoyl-3-chloropropanediol (3-MCPD 1-monopalmitate) and 1,2-bis-palmitoyl-3-chloropropanediol (3-MCPD dipalmitate) in Swiss mice were examined, along with their cytotoxicity in NRK-52E rat kidney cells. LD50 (median lethal dose) value of 3-MCPD 1-monopalmitate was determined 2676.81mg/kg body weight (BW). The results showed that 3-MCPD 1-monopalmitate dose-dependently decreased the mean body weight, and caused significant increase of serum urea nitrogen and creatinine in dead mice compared to the control and survived mice. Major histopathological changes in mice fed 3-MCPD 1-monopalmitate were renal tubular necrosis, protein casts and spermatids decrease in the seminiferous tubules. According to the limit test for 3-MCPD dipalmitate, LD50 value of 3-MCPD dipalmitate was presumed to be greater than 5000mg/kg BW. Obvious changes were not observed on mean body weight, absolute and relative organ weight or serum urea nitrogen and creatinine levels in mice fed 3-MCPD dipalmitate. However, renal tubular necrosis, protein casts and spermatids decrease were also observed in the dead mice. In addition, MTT and LDH assay results only showed the cytotoxicity of 3-MCPD 1-monopalmitate in NRK-52E rat kidney cells in a dose-dependent manner. Together, the results indicated a greater toxicity of 3-MCPD 1-monopalmitate compared to 3-MCPD dipalmitate. © 2012 Elsevier Ltd.


Zhang X.,Shanghai JiaoTong University | Gao B.,Shanghai JiaoTong University | Qin F.,Shanghai JiaoTong University | Shi H.,Shanghai JiaoTong University | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2013

The present study was conducted to test the hypothesis that a free radical was formed and mediated the formation of 3-monochloropropanediol (3-MCPD) fatty acid diesters, a group of food contaminants, from diacylglycerols at high temperature under a low-moisture condition for the first time. The presence of free radicals in a vegetable oil kept at 120 C for 20 min was demonstrated using an electron spin resonance (ESR) spectroscopy examination with 5,5-dimethylpyrroline-N-oxide (DMPO) as the spin trap agent. ESR investigation also showed an association between thermal treatment degree and the concentration of free radicals. A Fourier transform infrared spectroscopy (FT-IR) analysis of sn-1,2-stearoylglycerol (DSG) at 25 and 120 C suggested the possible involvement of an ester carbonyl group in forming 3-MCPD diesters. On the basis of these results, a novel free radical mediated chemical mechanism was proposed for 3-MCPD diester formation. Furthermore, a quadrupole-time of flight (Q-TOF) MS/MS investigation was performed and detected the DMPO adducts with the cyclic acyloxonium free radical (CAFR) and its product MS ions, proving the presence of CAFR. Furthermore, the free radical mechanism was validated by the formation of 3-MCPD diesters through reacting DSG with a number of organic and inorganic chlorine sources including chlorine gas at 120 and 240 C. The findings of this study might lead to the improvement of oil and food processing conditions to reduce the level of 3-MCPD diesters in foods and enhance food safety. © 2013 American Chemical Society.


PubMed | Shanghai JiaoTong University, University of Maryland University College, Ningbo University and Wilmar Biotechnology Research and Development Center Shanghai Company
Type: Journal Article | Journal: Journal of agricultural and food chemistry | Year: 2016

The present study investigated the possible mechanism of free radical scavengers on mitigation of 3-monochloro-1,2-propanediol (3-MCPD) fatty acid ester formation in vegetable oils. The electron spin resonance investigation showed that the concentration of free radicals could be clearly decreased in 1,2-distearoyl-sn-glycerol (DSG) samples by all four antioxidants (l-ascorbyl palmitate, -tocopherol, lipophilic tea polyphenols, and rosemary extract) at 120 C for 20 min under a N2 atmosphere. Moreover, the rosemary extract exhibited the highest inhibition efficiency. The Fourier transform infrared spectroscopy examination of DSG with -tocopherol at 25 and 120 C revealed that -tocopherol could prevent the involvement of an ester carbonyl group of DSG in forming the cyclic acyloxonium free radical intermediate. Furthermore, the ultraperformance liquid chromatography-quadrupole-time-of-flight mass spectrometry analysis showed that -tocopherol could suppress the formation of 3-MCPD di- and monoesters. Finally, the four antioxidants could decrease 3-MCPD esters in the palm oil during deodorization. Particularly, the rosemary extract also showed the highest efficiency in 3-MCPD ester mitigation.


Xu Z.,Jiangnan University | Xu Z.,Wilmar Biotechnology Research and Development Center Shanghai Co. | Jin J.,Jiangnan University | Zheng M.,Wilmar Biotechnology Research and Development Center Shanghai Co. | And 4 more authors.
Food Chemistry | Year: 2016

The aim of the study is to prepare co-surfactant free microalgal oil microemulsions and investigate their properties as well as processing stability for food application. The physicochemical characteristics of the microemulsions were investigated by dynamic light scattering (DLS), turbidity, conductivity, rheological measurements and transmission electron microscopy (TEM). Within the microemulsion region, when the surfactant to oil ratio was 9:1, the hydrodynamic diameter (Dh) was 18 nm; when the surfactant to oil ratio was 7.5:1, the hydrodynamic diameter (Dh) was 50 nm. Rheological studies proved that the microemulsion system was a pseudoplastic fluid, which followed a shear thinning flow behavior. The loss rate of docosahexaenoic acid (DHA) was less than 5%wt after ultra high temperature (UHT) and high temperature short time (HTST) thermal treatments. A high content of CaCl2 (10.0%wt) could not destroy the microemulsion system, and it could be stored at 4°C for two years. © 2016 Elsevier Ltd. All rights reserved.


Xu Z.,Jiangnan University | Xu Z.,Wilmar Biotechnology Research and Development Center Shanghai Co. | Jin J.,Jiangnan University | Adhikari P.,Cargill Inc. | And 4 more authors.
RSC Advances | Year: 2016

Medium- and long-chain triacylglycerol (MLCT) is increasingly popular because of its anti-obesity ability, and therefore it is considered as a healthy functional fat. Sheaolein (SO)-based cold soluble powder fats with high MLCT level were studied by chemical interesterification of SO and palm kernel stearin (PKST) (SO : PKST, 80 : 20; 60 : 40; 50 : 50; 40 : 60; 20 : 80). Physicochemical properties of interesterified products, mainly including fatty acid composition, triacylglycerol composition, solid fat content, melting point, melting and crystallization behavior, and sensory characteristics were comparatively analyzed with the original substrate mixture. In addition, some of the properties were compared with the traditional commercial powder fats. The interesterified fat of 40 : 60 (SO : PKST) showed ideal physicochemical properties for possible use as a cold soluble powder fat with healthy conception. In particular, the MLCT level increased from 12.3% to 53.0%, and the reduction of trisaturated triacylglycerol and the content of trans fatty acid (less than 1%) were also desirable. © The Royal Society of Chemistry 2016.


PubMed | Wilmar Biotechnology Research and Development Center Shanghai Co. and Jiangnan University
Type: | Journal: Food chemistry | Year: 2016

The aim of the study is to prepare co-surfactant free microalgal oil microemulsions and investigate their properties as well as processing stability for food application. The physicochemical characteristics of the microemulsions were investigated by dynamic light scattering (DLS), turbidity, conductivity, rheological measurements and transmission electron microscopy (TEM). Within the microemulsion region, when the surfactant to oil ratio was 9:1, the hydrodynamic diameter (Dh) was 18nm; when the surfactant to oil ratio was 7.5:1, the hydrodynamic diameter (Dh) was 50nm. Rheological studies proved that the microemulsion system was a pseudoplastic fluid, which followed a shear thinning flow behavior. The loss rate of docosahexaenoic acid (DHA) was less than 5%wt after ultra high temperature (UHT) and high temperature short time (HTST) thermal treatments. A high content of CaCl2 (10.0%wt) could not destroy the microemulsion system, and it could be stored at 4C for two years.


Adhikari P.,Wilmar Biotechnology Research and Development Center Shanghai Co. | Hu P.,Wilmar Biotechnology Research and Development Center Shanghai Co. | Yafei Z.,Wilmar Biotechnology Research and Development Center Shanghai Co.
JAOCS, Journal of the American Oil Chemists' Society | Year: 2012

Interesterified fat was produced from soybean oil (SBO) and palm stearin (PS) using two different weight ratios of substrates. Conjugated linoleic acid (CLA; 10 wt% on the weight of SBO and PS) was used as a functional fatty acid. Interesterification and acidolysis was simultaneously carried out to exchange fatty acids and incorporate CLA in the triacylglycerol (TAG) backbone, respectively, using immobilized lipase. Comparative study was carried out between interesterified fats and blends (before interesterification) for the quantification of physical properties (i.e., solid fat content, melting and crystallization behavior) and oxidative stability. In the interesterified fat 5.2-6.1 % CLA was incorporated in the TAG backbone. Blends showed higher solid fat content (SFC) and melting point than interesterified fat at each measured temperature. The Rancimat test was performed for the oxidative stability where the interesterified fat showed significantly lower induction time than physical blends. After the addition of antioxidants such as butylated hydroxytoluene (BHT), rosemary extract, tertiary butylhydroquinone (TBHQ), propyl gallate (PG), etc. into the interesterified fat, the induction time was significantly increased. On the other hand, different deacidification methods (alkaline, batch deodorized and short path distillation) were performed after interesterification to remove the free fatty acids. After deacidification, oxidative stability of alkaline deacidified sample showed significantly (P B 0.05) longer induction time compared to short path distillation (SPD) and physically deacidified samples. In this study, interesterified functional fat that may have a potential functionality for the margarines and shortenings were produced and their oxidative stability was observed. © AOCS 2012.


Wang Y.,Fuzhou University | Fu H.,Fuzhou University | Xiao Z.,Fuzhou University | Zhang H.,Wilmar Biotechnology Research and Development Center Shanghai Co. | And 2 more authors.
Journal of Chinese Institute of Food Science and Technology | Year: 2015

LC-MS, HPLC and atomic absorption spectrometry were used to reveal the reason why γ-oryzanol leading to the increase of free fatty acid values of edible oils while titrated by alkali. When phenolphthalein was used as indicator to determine the free fatty acid values of oils, the hydrogen atom in the phenolic hydroxyl group of γ-oryzanol appeared to be weak acidic and was replaced by a potassium atom, thus resulting in the excessive consumption of alkali. On average, 38.96% of γ-oryzanol transformed into potassium derivatives and was determined by atomic absorption spectrometry. The true acids value of the free fatty acid of oils including γ-oryzanol should be calculated by the acids value observed subtract the acids value caused by γ-oryzanol, the specific formula was presented. © 2015, Chinese Institute of Food Science and Technology. All right reserved.

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