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Lai Y.-T.,South China Agricultural University | Ouyang J.-Y.,South China Agricultural University | Guo Y.-T.,South China Agricultural University | Yang T.-W.,South China Agricultural University | And 4 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2014

Effects of nonylphenol (NP) on monoamine oxidase (MAO) activity and 5-hydroxytryptamine (5-HT) level of rats were investigated. The toxic mechanisms of NP on catabolism of 5-HT were also analyzed. 24 male SD rats were randomly divided into 4groups, namely NP low-dose group 30 mg/(kg·bw), NP medium-dose group 90 mg/(kg·bw), NP high-dose group 270 mg/(kg·bw) and control group (equal volume of the solvent). NP in corn oil was administrated orally to rats once every other day for 28days, and rats in control group was only given corn oil. The increment of rat body weight in NP high-dose group was lower than that of control group (P<0.01). From the third week of exposure, significant differences were found for the food utilization rates, the liver, kidney and testis coefficients between treatment groups and control group (P<0.05, P<0.01, P<0.01, P<0.05). Compared with control group, significantly lower MAO activities of plasma and liver homogenate and higher 5-HT levels were observed in treatment groups (P<0.01, P<0.05, P<0.01). NP exposure has a dose-dependent effect on MAO activity and 5-HT level of rats, suggesting that NP may affect the metabolic network of 5-HT by inhibiting its catabolism. Source


Wang Q.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Huang Q.-X.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Sun Y.-M.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Liu Y.-J.,South China Agricultural University | And 2 more authors.
Gaodeng Xuexiao Huaxue Xuebao/Chemical Journal of Chinese Universities | Year: 2013

Fluorescence-labeled melamine tracer(MEL-EDF) was synthesized via the reaction of melamine hapten(MEL) with 1-(2-aminoethyl)-3-(3', 6'-dihydroxy-3-oxo-3H-spiro[isobenzofuran-1, 9'-xanthene]-5-yl)thiourea(EDF). The tracer was then incubated with the antibody to prepare the single reagent immunocomplex, and both the binding and displacement kinetics were evaluated to obtain the equilibration time. Finally, a single reagent fluorescence polarization immunoassay(SR-FPIA) was developed to measure melamine. The SR-FPIA method demonstrated a detection limit(LOD) of 3.2 ng/mL, a 50% inhibition value(IC50) of 157.1 ng/mL and a working range(IC20-IC80) of 12.2-1012.4 ng/mL. The results indicated the proposed method can meet the detection requirement for the maximum residue level of melamine set by Chinese government and Codex Alimentarius Commission(CAC). The detection could be finished within 15 min, and the obtained single reagent immunocomplex was stable for more than 30 days at 4°C. This work will benefit to further development of SR-FPIA kit for melamine. Source


Chu Y.,South China Agricultural University | Liang D.,Guangdong Testing Institute of Product Quality Supervision | Sun Y.,South China Agricultural University | Sun Y.,Guangdong Provincial Key Laboratory of Food Quality and Safety | And 3 more authors.
Journal of the Chinese Cereals and Oils Association | Year: 2014

A gas chromatography-mass spectrometry method has been developed for the simultaneous determination on 16 phthalate acid esters (PAEs) in different kinds of foods. Different separation and purification methods have been selected according to the types of foods. The oily samples were extracted with normal hexane by ultrasonically assisted procedure; the extracts were cleaned up by GPC and determined by GC-MS. Within the range of phthalate acid esters concentration of 0.02~5 mg/L, a fine relationship was observed between the peak area and the phthalic esters concentration. All of the correlation coefficients were higher than 0.999.The detection limit was achieved as 0.02 mg/kg. The recovery range of 16 phthalate acid esters was 75%~115% with the relative standard deviation (RSD, n=3) of 1%~10%. Source


Yang T.-W.,South China Agricultural University | Lai Y.-T.,South China Agricultural University | Guo Y.-T.,South China Agricultural University | Ouyang J.-Y.,South China Agricultural University | And 4 more authors.
Academic Journal of Second Military Medical University | Year: 2014

Objective To observe the effect of nonylphenol (NP) on plasma and urine 5-hydroxytryptamine (5-HT) levels and expression of 5-HT and of 5-HT2A receptor in the platelets of rats, so as to explore the toxic mechanisms of NP on 5-HT and 5-HT2A receptor.Methods A total of 24 male SD rats were equally randomized into 4 groups: solvent control group, NP low-dose group (30 mg/[kg • d]), NP medium-dose group (90 mg/[kg • d]) and NP high-dose group (270 mg/[kg • d]). The animals were gavaged with NP every other day for 28 days; then the plasma and 24 h urine levels of 5-HT, 5-HT and 5-HT2A expression in the platelets were examined.Results The levels of 5-HT in the plasma and platelets of rats were increased and the expression of 5-HT2A receptor in platelets was decreased with the increase of NP exposure dose. The plasma and platelet 5-HT levels in the medium- and high- NP dose groups were significantly higher than those in the control group(P< 0. 01); the platelet level of 5-HT2A receptor in the high- NP dose group was significantly lower than that in the control group CP Source


Tang Q.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Lei H.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Huang L.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Sun Y.,Guangdong Provincial Key Laboratory of Food Quality and Safety | Yang J.,Guangdong Provincial Key Laboratory of Food Quality and Safety
Advanced Materials Research | Year: 2012

For the generation of antibodies against small hapten molecules, the hapten is crosslinked with some carrier protein to make it immunogenic. However, it was rarely systematically studied about the effect of modified carrier protein on the obtained antibody nature. In this study, folic acid as the model hapten was coupled to natural and surface-modified bovine serum albumin (BSA) using modifying agent amidocaproic acid (ACA) and hexamethylene diamine (HDA). The three immunogens of FA-BSA, FA-ACA-BSA, FA-HDA-BSA were confirmed by SDS-PAGE and ultraviolet spectrum (UV). The Balb/C mice were immunized with the artificial antigen to obtain three specific antibody with indirect competitive enzyme-linked immunosorbent assay (icELISA) method to compare the performance of antibodies obtained based on different imunogen. The results indicate that the conjugates were successfully synthesized and the coupling ratio from the high to the low was HDA-BSA > ACA-BSA > BSA, while the titer of antibody was ACA-BSA > BSA >HDA-BSA and the IC50 was HDA-BSA < ACA-BSA < BSA. This suggests that sensitivity of antibody was improved by cationizing the carrier protein. © (2012) Trans Tech Publications, Switzerland. Source

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