scholarly journals Enzyme-Linked Immunosorbent Assay for Simultaneous Detection of Two Fungicides Kresoxim-methyl and Trifloxystrobin in Oranges

2016 ◽  
Vol 34 (No. 5) ◽  
pp. 429-438 ◽  
Author(s):  
Yang Wei ◽  
Zhu Jie ◽  
Liu Ming-Qi ◽  
Dai Xian-Jun

To assemble an indirect competitive enzyme-linked immunosorbent assay (ELISA) for estimating two strobilurin fungicides at the same time, the hapten was synthesised which contained the common active group, (E)-2-(2-bromo-phenyl)-2-(methoxyimino) acetic acid methyl ester (OEBr) in kresoxim-methyl and trifloxystrobin. The immunogen and coating antigen were respectively prepared through conjugating the above-mentioned hapten with BSA and OVA by the mixed anhydride and activated ester methods, and polyclonal antibodies were produced by immunised rabbits. An enzyme-linked immunosorbent assay was developed for simultaneous detection of kresoxim-methyl and trifloxystrobin. In ELISA, the antiserum showed high affinity and sensitivity to kresoxim-methyl and trifloxystrobin, and their IC<sub>50</sub> value and detection limit (expressed as IC<sub>10</sub>) were 14.7 and 0.0044 µg/ml, respectively, for kresoxim-methyl, and 22.9 and 0.014 µg/ml, respectively for trifloxystrobin. The cross-reaction rate was below 0.1% for other strobilurin fungicides. Recovery study of ELISA from spiked samples of homogenised peeled oranges (final concentrations of 100, 10, and 1 µg/ml) resulted in recovery levels in the range of 82–104%.

1990 ◽  
Vol 73 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Fun S Chu ◽  
Xuan Huang ◽  
R D Wei

Abstract A direct competitive enzyme-linked immunosorbent assay (ELISA) for the freshwater blue-green algal toxin mlcrocystln (MCYST) In algae and water was developed. The assay Involves coating antl-MCYST-variant leuclne-arglnine (LR) antibody to the ELISA plate and the use of MCYST-LRperoxidase as the enzyme marker. The linear portion of the standard curve for MCYST in phosphate buffer containing saline (PBS) was 0.5-10.0 ng/mL (25-500 pg/assay). The minimum detection level for MCYST-LR was 0.20 ng/mL (10 pg/assay). Contaminated water could be directly used In the ELISA. The overall analytical recoveries for MCYST-LR added to water at levels of 1-20 ng/mL was 83.4%. For analysis of cellular MCYST, the toxin was first extracted from the algae with 0.1M ammonium bicarbonate, diluted with PBS to less than 0.5 mg dried algae/mL (&lt;5.0 mg wet welght/mL) and directly used in the ELISA. C-18 reverse-phase Sep-Pak cartridges effectively adsorbed MCYST from the toxln-containlng solutions. The toxin could be recovered from the cartridge by elutlng with 60% methanol. Using this approach, an algae extract that was relatively free of MCYST was prepared and was used in a recovery study. The overall analytical recovery of MCYST added to the algae extract In the range of 0.25-20 ppm was 83% with a coefficient of variation of 11.9%. The detection limit for MCYST In dried algae was about 0.25-0.5 pg/g (0.25-0.5 ppm) lyophlllzed algae sample. This method was applied for the analysis of several naturally occurring algal blooms. Limited samples were also analyzed for MYCST by liquid chromatography. ELISA data were in general agreement with those obtainedby liquid chromatography. MCYST concentrations from 0.006 to 2.9 fig/g (6 to 2900 ppb) and from 26 to 5200 /ig/g (26 ppm to 5200 ppm) were found In water and algae (dried weight), respectively


1991 ◽  
Vol 37 (10) ◽  
pp. 1742-1745 ◽  
Author(s):  
R Saïle ◽  
A Kandoussi ◽  
M Deveaux ◽  
J Descamps ◽  
E Hachulla ◽  
...  

Abstract This enzyme-linked immunosorbent assay procedure for quantifying serum amyloid P (SAP) in human plasma makes use of affinity-purified polyclonal antibodies to SAP in a "sandwich"-type format. The procedure is sensitive, reproducible, simple, and easily automatable. Results correlate well with those by a rocket immunoelectrophoresis method performed with the same antibodies. Sera from apparently normal individuals had a mean SAP content of 44.17 mg/L and increased with age.


1998 ◽  
Vol 70 (6) ◽  
pp. 1092-1099 ◽  
Author(s):  
Yukio Sugawara ◽  
Shirley J. Gee ◽  
James R. Sanborn ◽  
S. Douglass Gilman ◽  
Bruce D. Hammock

2013 ◽  
Vol 781-784 ◽  
pp. 1630-1636 ◽  
Author(s):  
Jie Biao Guo ◽  
Xuan Xin ◽  
Rui Min Zhong ◽  
Xing Ping Li

To generate a group-specific monoclonal antibody (McAb) against danofloxacin (DANO), enrofloxacin (ENR) and ciprofloxacin (CIP), glutaraldehyde was used to link the presentative hapten of CIP to the immunogen and coating antigen, respectively, leaving the common structure of these 3 drugs exposed in both conjugates as a major antigenic site. Consequently, a McAb (6D3) with high cross-reactivity to this three antibiotics has been obtained by using hybridomas technique. In a biotin-avidin mediated enzyme-linked immunosorbent assay, the IC50values for DANO, ENR and CIP were 5.1, 4.5 and 4.2 ng mL-1, respectively. The ELISA was used for the detection of spiked DANO and ENR+CIP in milk. The recoveries ranged from 74.1 to 92.4% and coefficients of variation were in a range of 6.6-11.9%. The accuracies and sensitivity of the method were good for simultaneous analysis of the 3 drugs in milk after a simple sample extraction process.


2001 ◽  
Vol 8 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Nelydia F. Concepcion ◽  
Carl E. Frasch

ABSTRACT The specificity of the immune response to the 23-valent pneumococcal-polysaccharide (PS) vaccine in healthy adults and to a pneumococcal conjugate vaccine in infants was examined by measuring immunoglobulin G (IgG) antibody titers by enzyme-linked immunosorbent assay (ELISA) and the opsonophagocytosis assay. ELISA measures total antipneumococcal IgG titers including the titers of functional and nonfunctional antibodies, while the opsonophagocytosis assay measures only functional-antibody titers. Twenty-four pairs of pre- and post-pneumococcal vaccination sera from adults were evaluated (ELISA) for levels of IgG antibodies against serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F. Twelve of the pairs were also examined (opsonophagocytosis assay) for their functional activities. The correlation coefficients between assay results for most types ranged from 0.75 to 0.90, but the correlation coefficient was only about 0.6 for serotypes 4 and 19F. The specificities of these antibodies were further examined by the use of competitive ELISA inhibition. A number of heterologous polysaccharides (types 11A, 12F, 15B, 22F, and 33A) were used as inhibitors. Most of the sera tested showed cross-reacting antibodies, in addition to those removed by pneumococcal C PS absorption. Our data suggest the presence of a common epitope that is found on most pneumococcal PS but that is not absorbed by purified C PS. Use of a heterologous pneumococcal PS (22F) to adsorb the antibodies to the common epitope increased the correlation between the IgG ELISA results and the opsonophagocytosis assay results. The correlation coefficient improve from 0.66 to 0.92 for type 4 and from 0.63 to 0.80 for type 19F. These common-epitope antibodies were largely absent in infants at 7 months of age, suggesting the carbohydrate nature of the epitope.


1990 ◽  
Vol 57 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Elena Rodríguez ◽  
Rosario Martín ◽  
Teresa García ◽  
Pablo E. Hernández ◽  
Bernabé Sanz

SummaryAn indirect enzyme-linked immunosorbent assay was successfully developed for the detection of defined amounts of cows' milk (1–50%) in sheeps' milk and cheese. The assay used polyclonal antibodies raised in rabbits against bovine caseins (BC). The anti-BC antibodies were recovered from the crude antiserum by immunoadsorption and elution from a column containing BC. The antibodies were biotinylated and rendered cows' milk specific by mixing them with lyophilized ovine and caprine caseins. ExtrAvidin-peroxidase was used to detect the biotinylated anti-BC antibodies bound to BC immobilized on 96-well plates. Subsequent enzymic conversion of substrate gave clear absorbance differences when assaying mixtures of sheeps' milk and cheese containing variable amounts of cows' milk.


2008 ◽  
Vol 71 (9) ◽  
pp. 1868-1874 ◽  
Author(s):  
ERIC A. E. GARBER ◽  
JENNIFER L. WALKER ◽  
THOMAS W. O'BRIEN

Abrin is a toxic ribosome-inactivating protein present in beans of Abrus precatorius, also known as rosary peas. The possibility that abrin could be used to adulterate food has made the development of assays for the detection of abrin a priority. Rabbit-derived polyclonal antibodies and mouse monoclonal antibodies were prepared against a mixture of abrin isozymes. The specificity and cross-reactivity of the antibodies were evaluated against a challenge library of 40 grains, nuts, legumes, and foods. An enzyme-linked immunosorbent assay (ELISA) and an electrochemiluminescence (ECL)–based assay were assembled and optimized. Polyclonal (capture) and polyclonal (detection) ELISAs, polyclonal and monoclonal ELISAs, and polyclonal and monoclonal ECL assays had limits of detection (LODs) of 0.1 to 0.5 ng/ml for abrin in buffer. The LOD for abrin dissolved into juices, dairy products, soda, chocolate drink, and condiments and analyzed with the ECL assay ranged from 0.1 to 0.5 ng/ml in the analytical sample. In contrast, the LODs for the ELISAs ranged from 0.5 to 10 ng/ml in the analytical sample.


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