Ji Li

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Organization: China Agricultural University

Department: College of Resources and Environmental Sciences

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Chemicals
References

Isolation and Application of Thermophilic and Psychrophilic Microorganisms in the Composting Process

Co-reporter:Lin Wang;Liying Wang;Dingmei Wang

Waste and Biomass Valorization 2014 Volume 5( Issue 3) pp:433-440

Publication Date(Web):2014 June

DOI:10.1007/s12649-013-9253-8

Because temperature is a limited factor in compost process, we attempted to isolate and screen efficient themophilic and psychrophilic strains from composts and soils adapting to high and low temperature, respectively. Firstly, two cellulose-effectively-decomposing thermophilic bacteria, HNS39 and HNC41, were screened from 13 thermophilic compost samples and one soil sample from tropical rain forest. By addition of microbial agents with single HNS39, HNC41, or their mixture (1:1 v/v), the progress of composing was more effectively improved with HNS39. According to 16S rDNA gene sequencing and its growth characteristics, HNS39 was identified as Geobacillus sp. Meanwhile, the psychrotrophs strains of B6-38, B10-40, B10-44 isolated, could rapidly reproduce and effectively degrade organic compounds with highest enzyme activity in low temperature from 10 samples collected from sewage sludge, poultry manure and paddy soil. It was indicated that cold-adapted bacteria had a better effect on the raise of composting temperature, especially B6-38 with the highest protease activity of 46.08 U/ml. It grew fast and had good ability of enzyme production and strong organic degradation capabilities at 15 °C. By identification, Strain B6-38 was associated with Aeromonasa sp. Therefore, the research was fully shown that the isolated thermophilic and psychrophilic microorganisms had high potential of application in the composting under high and low temperature.

A highly sensitive and selective immunoassay for the detection of tetrabromobisphenol A in soil and sediment

Co-reporter:Ting Xu, Jia Wang, Shang-zhong Liu, Cong Lü, Weilin L. Shelver, Qing X. Li, Ji Li

Analytica Chimica Acta 2012 Volume 751() pp:119-127

Publication Date(Web):2 November 2012

DOI:10.1016/j.aca.2012.06.030

Tetrabromobisphenol A is the most widely used brominated flame retardant. A sensitive and selective enzyme-linked immunosorbent assay (ELISA) for the detection of tetrabromobisphenol A was developed. The limit of detection and the inhibition half-maximum concentration of tetrabromobisphenol A in phosphate buffered saline with 10% methanol were 0.05 and 0.87 ng mL−1, respectively. Cross-reactivity values of the ELISA with a set of important brominated flame retardants including tetrabromobisphenol A-bis(2,3-dibromopropylether), 2,2′,6,6′-tetrabromobisphenol A diallyl ether, hexabromocyclododecane, 1,2-bis(pentabromodiphenyl) ethane, 1,2-bis(2,4,6 tribromophenoxy) ethane, bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate, 2-ethylhexyl-2,3,4,5-tetrabromobenzoate, and polybrominated diphenyl ethers were <0.05%. Concentrations of tetrabromobisphenol A determined by ELISA in the soils from farmlands, the soils from an e-waste recycling site, and the sediments of a canal were in the range of non-detectable–5.6 ng g−1, 26–104 ng g−1 and 0.3–22 ng g−1 dw, respectively, indicating the ubiquitous pollution of tetrabromobisphenol A. The results of this assay for 16 real world samples agreed well with those of the liquid chromatography–tandem mass spectrometry method, indicating this ELISA is suitable for screening of tetrabromobisphenol A in environmental matrices.Graphical abstractHighlight► The developed ELISA is highly sensitive and selective to TBBPA. ► Accuracy of this ELISA for TBBPA in environmental matrices were reasonable. ► TBBPA levels found in environmental samples showed variation. ► ELISA for TBBPA in real samples correlated well with LC–MS/MS method.

Strip-based immunoassay for the simultaneous detection of the neonicotinoid insecticides imidacloprid and thiamethoxam in agricultural products

Co-reporter:Ting Xu, Qi Gong Xu, Hao Li, Jia Wang, Qing X. Li, Weilin L. Shelver, Ji Li

Talanta 2012 Volume 101() pp:85-90

Publication Date(Web):15 November 2012

DOI:10.1016/j.talanta.2012.08.047

A semiquantitative strip immunoassay was developed for the rapid detection of imidacloprid and thiamethoxam in agricultural products using specific nanocolloidal gold-labeled monoclonal antibodies. The conjugates of imidacloprid–BSA, thiamethoxam–BSA and goat anti-mouse IgG were coated on the nitro-cellulose membrane of the strip, serving as test lines and control line, respectively. The flow of the complexes of gold labeled antibodies and insecticides along the strip resulted in intensive color formed on the test lines inversely proportional to the concentrations of imidacloprid and thiamethoxam. The visual detection limits of imidacloprid and thiamethoxam in assay buffer were 0.5 and 2 ng mL−1, respectively. Matrix interference of cucumber, tomato, lettuce, apple, and orange on the strip assay could be eliminated by diluting sample extracts with assay buffer. The strip analysis of imidacloprid and thiamethoxam in these samples was compared to liquid chromatography–mass spectrometry and the results were in good agreement. The strip was stable for storage more than 5 months at 4 °C. The strip assay is a rapid and simple method for the simultaneous screening of imidacloprid and thiamethoxam in agricultural products.Highlights► Strip assay is easy, rapid and convenient and no equipment required. ► LODs for imidacloprid and thiamethoxam were 0.5 and 2.0 ng mL−1, respectively. ► Sample extracts were appropriately diluted prior to the assay without any clean-up. ► The results of strip assay agreed well with those of the LC–MS method for insecticides.

Development of an enzyme-linked immunosorbent assay specific to Sudan red I

Co-reporter:Ting Xu, Ke Yi Wei, Jia Wang, Sergei A. Eremin, Shang Zhong Liu, Qing X. Li, Ji Li

Analytical Biochemistry 2010 Volume 405(Issue 1) pp:41-49

Publication Date(Web):1 October 2010

DOI:10.1016/j.ab.2010.05.031

To obtain antibodies to develop an enzyme-linked immunosorbent assay (ELISA) for the analysis of Sudan red I, haptens were designed and synthesized via four different strategies: (i) attachment of a spacer at the para position of the benzene ring, (ii) attachment of a spacer at the naphthol part, (iii) attachment of a spacer at the hydroxyl group of the Sudan red I molecule, and (iv) use of a fragment of the target molecule. A total of 10 haptens were used to generate immunogens, coating antigens, and polyclonal antibodies. One of the heterologous ELISAs developed exhibited an IC50 of 1.6 ng/ml, a limit of detection (LOD) of 0.03 ng/ml, and a dynamic range between 0.1 and 14 ng/ml. The assay had 13% cross-reactivity with Para red and negligible cross-reactivity with other structure-related compounds. This ELISA was much more specific than those published previously. This assay was used to determine Sudan red I residues in tomato sauce and chili powder samples after simple pretreatment. The results were validated by comparison with high-performance liquid chromatography (HPLC). The average recoveries of Sudan red I by ELISA and HPLC were in ranges of 70–97% and 82–114%, respectively, indicating suitability of the developed ELISA for screening of Sudan red I in foods.

Development of an Indirect Competitive ELISA Based on Polyclonal Antibody for the Detection of Diethylstilbestrol in Water Samples

Co-reporter:Wen-Jun Wang;Yun Ling;Ting Xu;Hong-Bin Gao;Wei Sheng

Chinese Journal of Chemistry 2007 Volume 25(Issue 8) pp:

Publication Date(Web):15 AUG 2007

DOI:10.1002/cjoc.200790214

An indirect competitive enzyme-linked immunosorbent assay (icELISA) based on polyclonal antibody for the estrogen diethylstilbestrol (DES) was developed. With this aim, two different haptens mono-O-3-carboxypropyl- diethylstilbestrol (DES-CP) and mono-O-carboxymethyldiethylstilbestrol (DES-CM) with carboxylic group that preserve the molecular structure character of diethylstilbestrol were synthesized. The haptens were conjugated with the carrier proteins bovine serum albumin (BSA) by mixed-anhydride method for immunogen and conjugated with ovalbumin (OVA) by active ester method for coating antigen. Polyclonal antibodies for diethylstilbestrol were raised by immunizing mice with immune antigen DES-CP-BSA. Under optimized system, the lowest limit of detection (LLD) of diethylstilbestrol was 0.01 ng/mL, and IC₅₀ = 1.02 ng/mL. Its analogs were tested and no obvious cross-reactivity was found to anti-diethylstilbestrol antibody. DES-fortified water samples were determined by simple dilution to diminish the matrix effect. The comparison between the amount of DES estimated by ELISA and the amount added indicates good agreement for all water samples tested, with mean recovery values ranging from 86% to 120.2%.

Development of Monoclonal Antibody-based Enzyme-linked Immunosorbent Assay to the Estrogen Diethylstilbestrol

Co-reporter:Wen-Jun Wang;Ji-Xun Zhao;Guo-Zhong Zhang;Ting Xu;Wei Sheng

Chinese Journal of Chemistry 2006 Volume 24(Issue 12) pp:

Publication Date(Web):4 DEC 2006

DOI:10.1002/cjoc.200690329

Diethylstilbestrol (DES) is a synthetic estrogen that has ever been used worldwide. Polyclonal antibodies (PAbs) were used in immunoassay for detection of DES residues in environmental and agricultural samples in previous paper. In this paper, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed based on monoclonal antibody (MAb) for the determination of diethylstilbestrol. Mono-o-carboxypropyldiethylstilbestrol (DES-CP) and mono-o-carboxymethyldiethylstilbestrol (DES-CME) were synthesized to be haptens. DES-CP was coupled to bovine serum albumin (BSA) to be an immunogen in BALB/c female mouse for MAb production. The MAb was characterized for specificity and affinity to DES in icELISA. Under the optimum condition, the icELISA showed an IC₅₀ of 9.8 ng/mL, the limit of detection (IC₂₀) of 2.3 ng/mL and a working range of 2–42 ng/mL. Hexestrol and dienestrol exhibited cross-reactivity values were 44% and 27%, respectively. Cross-reactivity of natural estrogen 17β-estradiol was less than 0.1%. The influences of some factors such as salt concentration, pH and organic solvent concentration on the assay were evaluated. The concentrations of DES in the fortified water samples determined by the assay were correlated well with the fortification levels. The results were confirmed with analysis by HPLC.

Study of nitrate leaching and nitrogen fate under intensive vegetable production pattern in northern China

Co-reporter:Xiao-Zong Song, Chang-Xing Zhao, Xiao-Lan Wang, Ji Li

Comptes Rendus Biologies (April 2009) Volume 332(Issue 4) pp:385-392

Publication Date(Web):1 April 2009

DOI:10.1016/j.crvi.2008.11.005

Because of intensive vegetable production in plastic greenhouses in northern China, the potential risk of nitrate leaching to groundwater is increasingly apparent, threatening ecosystem services and the sustainability of food production. In the present work, nine drainable lysimeters were installed into vegetable fields, with in-situ loamy soils, in Shouguang City of the north China vegetable base. The experiments were conducted to quantify the magnitude and variability of nitrate leaching to groundwater and to access the fate of total fertilizer-N inputs in the area. The results obtained indicated that: under local conventional agronomic practices, there is a high discrepancy in leaching nitrate-N concentration (ranging from 17 to 457 mg L−1), and nitrate losses (152–347 kg N ha−1) were observed from 1-m soil profiles in the field. Meanwhile, high fertilizer N application resulted in low N efficiency, with only (33.0±13)% (mean±S.D.) of input N absorbed by the crops, while additionally nearly half of the total inputs of N were unaccounted in a partial N balance sheet. It is concluded that groundwater pollution associated with greenhouse-based vegetable production had been confirmed in Shouguang, adversely affecting water quality and leading to serial agro-ecological problems. To cite this article: X.-Z. Song et al., C. R. Biologies 332 (2009).