Multicolor enzyme-linked immunoassay method for visual readout of carbendazim

2021 ◽  
Author(s):  
Haoran Liu ◽  
Yiwen Wang ◽  
Ruijie Fu ◽  
Jing Zhou ◽  
Yanlin Liu ◽  
...  

Enzyme-linked immunosorbent assay (ELISA) with high specificity and sensitivity is one of the most popular techniques for detecting carbendazim (CBD), a commonly used benzimidazole fungicide in agriculture. However, the traditional...

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Min Chen ◽  
Tie-Gui Nan ◽  
Jie Xin ◽  
Li Cui ◽  
Bo Zhang ◽  
...  

Rhein is an important quality-control marker of Rheum officinale. The aim of this study was to develop an indirect competitive enzyme-linked immunosorbent assay (icELISA) for rhein detection, which acts as a powerful tool for quality control and proper usage of Rheum officinale. First, a specific and sensitive monoclonal antibody (mAb) against rhein was produced from a stable hybridoma cell line, 1F8, generated by the fusion of mouse myeloma sp2/0 with spleen cells obtained from a Bal b/c mouse immunized with rhein-BSA. Then, an icELISA method was developed with an IC50 value and working range of 0.05 μg L−1 and 0.02–0.11 μg L−1, respectively. The icELISA revealed high assay specificity, since it only had a relatively high cross reactivity with aloe-emodin (27%) and almost no cross reactivity with any other anthraquinones (<1%). When spiked with 0.2–2 mg kg−1 of rhein, the recoveries ranged from 84.19% to 102.90%. Finally, icELISA was used to detect rhein contents of Rheum officinale collected from different regions, and the results corresponded well with those of HPLC. Overall, the developed icELISA with high specificity and sensitivity provided a rapid and simple method for rhein detection, and it may be a powerful tool for quality control and proper usage of Rheum officinale.


2012 ◽  
Vol 466-467 ◽  
pp. 220-224
Author(s):  
Qing Ping Zhong ◽  
Yan Ting Liu ◽  
Yuan Ming Sun ◽  
Hoi Fu Yu ◽  
Hong Tao Lei

This study aimed to develop a method for the detection of tetrodotoxin (TTX) based on monoclonal antibody (McAb). The hapten TTX was linked to carrier protein keyhole limpet hemocyanin (KLH) as immunogen, and linked to ovalbumin (OVA) as coating antigen by the Mannich method. Then the 6~8 weeks Babl/c mice were immunized. After cell amalgamation, a cell line with high specificity and sensitivity was obtained, and McAb was produced. The indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed for detecting TTX. The optimized working conditions of the icELISA were 4.0 μg/mL coating antigen, 0.75 μg/mL McAb, 45 min competitive time, at room temperature (20~25 °C). The IC50value of this method was 24.0 ng/mL, the working ranges were 5.2~107.6 ng/mL, the intra-assay and inter-assay coefficient of variation (CV %) were 4.2 and 4.5, respectively. This investigation will benefit the assay kit development for detecting TTX.


1998 ◽  
Vol 5 (4) ◽  
pp. 550-555 ◽  
Author(s):  
Patrick L. McDonough ◽  
Richard H. Jacobson ◽  
John F. Timoney ◽  
Ahmed Mutalib ◽  
David C. Kradel ◽  
...  

ABSTRACT Many regulatory and diagnostic programs for the detection ofSalmonella enterica serotype Enteritidis infection in commercial poultry flocks have relied on rapid Pullorum agglutination tests to screen birds because of the shared antigens of S. enterica Enteritidis and S. enterica Pullorum and Gallinarum; however, the use of the enzyme-linked immunosorbent assay (ELISA) format affords better analytical sensitivity than crude agglutination tests. In this study, we adapted our earlier conventional indirect ELISA, using gm flagellin as the antigen, to a kinetics-based, computer-controlled ELISA (KELA). The KELA was used to screen for flagellin antibody from three commercial flocks: (i) a large flock involved in a U.S. Department of Agriculture trace back from a humanS. enterica Enteritidis foodborne outbreak (n = 3,209), (ii) a flock infected with the endemicS. enterica Enteritidis serotype but which also had multiple other salmonella serotypes (n = 65), and (iii) an S. enterica Pullorum-infected flock (n = 12). The first flock (S. entericaEnteritidis prevalence of 2.45% based on culture) provided a field test of the KELA and allowed the calculation of diagnostic sensitivity (D-Sn) and diagnostic specificity (D-Sp). With a cutoff of 10 (used for screening flocks [i.e., high sensitivity]), the KELA has a D-Sn of 95.2% and a D-Sp of 18.5%; with a cutoff of 140 (used in confirmatory flock testing [i.e., high specificity]), the KELA has a D-Sn of 28.0% and a D-Sp of 99.1%. We found that with a cutoff of 60 (D-Sn = 63.1%; D-Sp = 91.6%), we could eliminate reactions in the KELA caused by other non-S. enterica Enteritidis salmonellae. The KELA was also compared to two commercial rapid Pullorum tests, the Solvay (D-Sn = 94.9%; D-Sp = 55.5%) and the Vineland (D-Sn = 62.0%; D-Sp = 75.3%).


2004 ◽  
Vol 34 (5) ◽  
pp. 1525-1529 ◽  
Author(s):  
Cristiane Divan Baldani ◽  
Rosangela Zacarias Machado ◽  
Paulo de Tarso Landgraf Botteon ◽  
Felipe Santoro Takakura ◽  
Carlos Luiz Massard

A crude antigenic preparation of Babesia equi was used to develop and establish the suitability of an enzyme-linked immunosorbent assay (ELISA) for the detection of parasite carriers. Optimal dilutions of the antigen, using positive and negative reference sera, were determined by checkboard titrations. The specificity and sensitivity of the ELISA were 100 %. A total of 90 serum samples were taken from horses from the Northeast region of São Paulo State and examined for diagnosis of equine B. equi infection by ELISA. Approximately 75% (n=67) of all the horses tested were found serologically positive for B. equi. These results suggest that the ELISA described may prove to be an appropriate serological test for epidemiological studies on B. equi infections in the field and that equine piroplasmosis is a cause for serious concern in the State of São Paulo, Brazil.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sharif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamri ◽  
...  

Abstract As the Coronavirus Disease 2019 (COVID-19), which is caused by the novel SARS-CoV-2, continues to spread rapidly around the world, there is a need for well validated serological assays that allow the detection of viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used multiple indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological assays to study the antibody response in COVID-19 patients. In order to validate the assays we determined the cut off values, sensitivity and specificity of the assays using sera collected from pre-pandemic healthy controls, COVID-19 patients at different time points after disease-onset, and seropositive sera to other human coronaviruses (CoVs). The developed SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N)-based ELISAs not only showed high specificity and sensitivity but also did not show any cross-reactivity with other CoVs. We also show that all RT-PCR confirmed COVID-19 patients tested in our study developed both virus specific IgM and IgG antibodies as early as week one after disease onset. Our data also suggest that the inclusion of both S1 and N in serological testing would capture as many potential SARS-CoV-2 positive cases as possible than using any of them alone. This is specifically important for tracing contacts and cases and conducting large-scale epidemiological studies to understand the true extent of virus spread in populations.


Author(s):  
Abdullah Algaissi ◽  
Mohamed A. Alfaleh ◽  
Sherif Hala ◽  
Turki S. Abujamel ◽  
Sawsan S. Alamri ◽  
...  

As the coronavirus disease 2019 (COVID-19), which is caused by the novel SARS-CoV-2, continues to spread rapidly around the world, there is a need for well validated serological assays that allow the detection of viral specific antibody responses in COVID-19 patients or recovered individuals. In this study, we established and used multiple indirect Enzyme Linked Immunosorbent Assay (ELISA)-based serological assays to study the antibody response in COVID-19 patients. In order to validate the assays we determined the cut off values, sensitivity and specificity of the assays using sera collected from pre-pandemic healthy controls, COVID-19 patients at different time points after disease-onset, and seropositive sera to other human coronaviruses. The developed SARS-CoV-2 S1 subunit of the spike glycoprotein and nucleocapsid (N)-based ELISAs not only showed high specificity and sensitivity but also did not show any cross-reactivity with other CoVs. We also show that all RT-PCR confirmed COVID-19 patients tested in our study developed both virus specific IgM and IgG antibodies as early as week one after disease onset. Our data also suggest that the inclusion of both S1 and N in serological testing would capture as many potential SARS-CoV-2 positive cases as possible than using any of them alone. This is specifically important for tracing contacts and cases and conducting large-scale epidemiological studies to understand the true extent of virus spread in populations.


Author(s):  
Lúcia M. BRAGAZZA ◽  
Adelaide J. VAZ ◽  
Afonso D.C. PASSOS ◽  
Osvaldo M. TAKAYANAGUI ◽  
Paulo M. NAKAMURA ◽  
...  

Considering the impact of cysticercosis on public health, especially the neurologic form of the disease, neurocysticercosis (NC), we studied the frequency of positivity of anti-Taenia solium cysticercus antibodies in serum samples from 1,863 inhabitants of Cássia dos Coqueiros, SP, a municipal district located 80 km from Ribeirão Preto, an area considered endemic for cysticercosis. The 1,863 samples were tested by enzyme linked immunosorbent assay (ELISA) using an antigenic extract from Taenia crassiceps vesicular fluid (Tcra). The reactive and inconclusive ELISA samples were tested by immunoblotting. Of the 459 samples submitted to immunoblotting, 40 were strongly immunoreactive to the immunodominant 18 and 14 kD peptides. Considering the use of immunoblotting as confirmatory due to its high specificity, the anti-cysticercus serum prevalence in this population was 2.1%.


2007 ◽  
Vol 14 (3) ◽  
pp. 113-116 ◽  
Author(s):  
Léon Mutesa ◽  
François Boemer ◽  
Louis Ngendahayo ◽  
Stephen Rulisa ◽  
Emmanuel K Rusingiza ◽  
...  

Objectives: To evaluate the feasibility of systematic neonatal screening for sickle cell disease in the region of Great Lakes in Central Africa using a new approach with limited costs. Methods: Between July 2004 and July 2006, 1825 newborn dried blood samples were collected onto filter papers in four maternity units from Burundi, Rwanda and the East of the Democratic Republic of Congo. We tested for the presence of haemoglobin C and S in the eluted blood by an enzyme-linked immunosorbent assay (ELISA) test using a monoclonal antibody. All ELISA-positive samples (multiple of the median (MoM)≥ 1.5) were confirmed by a simple molecular test. The statistica software version 7.1 was used to create graphics and to fix the MoM cut-off, and the χ2 of Pearson was used to compare the genotype incidences between countries. Results: Of the 1825 samples screened, 97 (5.32%) were positive. Of these, 60 (3.28%) samples were heterozygous for Hb S, and four (0.22%) for Hb C; two (0.11%) newborns were Hb SS homozygotes. Conclusions: The lower cost and the high specificity of ELISA test are appropriate for developing countries, and such systematic screening for sickle cell anaemia is therefore feasible.


2005 ◽  
Vol 2 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Tang Yong ◽  
Chen Huan-Chun ◽  
Qin Ya-Li ◽  
He Qi-Gai ◽  
Jin Mei-Lli ◽  
...  

AbstractTo differentiate pigs infected withPseudorabies virus(PrV) from pigs vaccinated with gE-PrV, a glycoprotein E enzyme-linked immunosorbent assay (gE-ELISA) based on recombinant glycoprotein E (gE) (which was expressed byEscherichia coli, purified, denatured and renatured) was developed. By testing 115 serum samples, the diagnostic specificity and sensitivity of the developed gE-ELISA were evaluated to be 94.5% and 96.7%, respectively. Five serum samples were tested with plates from five lots, and the results had a coefficient of variation of less than 10%, showing good reproducibility of gE-ELISA. This gE-ELISA was compared with a commercial blocking ELISA by testing 356 serum samples. The agreement rate of the two assays was 92.13% (328/356). These results suggested that the gE-ELISA developed in our laboratory could be used in differentiating PrV-infected and gE-PrV-vaccinated pigs.


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