Immunological discrimination between a sap-staining fungus and a biological control fungus

1990 ◽  
Vol 68 (7) ◽  
pp. 1578-1588 ◽  
Author(s):  
Brian T. Luck ◽  
Colette Breuil ◽  
David L. Brown

An enzyme-linked immunosorbent assay (ELISA) was used to detect a sap-staining fungus, Ophiostoma piceae, and a biological-control agent, Gliocladium roseum, grown in liquid culture and in wood. A polyclonal serum prepared against whole cell fragments from broken mycelia of O. piceae detected O. piceae in liquid culture at 0.25 μg dry weight/mL; however, there was moderate cross-reactivity with G. roseum. Antiserum adsorbed on G. roseum had almost no reactivity with G. roseum but still reacted strongly with O. piceae. The specificity of these sera was verified, and the antigenic sites were localized, by immunogold labeling and electron microscopy. These studies confirmed that the adsorbed serum could differentiate between G. roseum and O. piceae and showed that the cell wall was the most reactive cellular component. These results are discussed in relation to the development of immunological probes for the detection of sap-staining and biological control fungi. Key words: polyclonal serum, enzyme-linked immunosorbent assay, immunogold labeling, sap-staining and biological control fungi, electron microscopy.

2006 ◽  
Vol 44 (9) ◽  
pp. 3432-3434 ◽  
Author(s):  
M. Giacchino ◽  
N. Chiapello ◽  
S. Bezzio ◽  
F. Fagioli ◽  
P. Saracco ◽  
...  

1986 ◽  
Vol 113 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Andrzej Gardas ◽  
Kathleen L. Rives

Abstract. A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of autoantibodies reacting with thyroid plasma membrane antigens has been established. Autoantibodies reacting with thyroid plasma membrane antigens were detected by the ELISA in 95% of untreated hyperthyroid Graves', 68% of antithyroid drug-treated Graves' up to four months of the therapy, in 62% of Hashimoto's thyroiditis and in 8.9% of toxic nodular goitre. The ELISA was negative in 100% healthy blood donors, 100% non-toxic nodular goitre, in 12 patients with rheumatoid arthritis, 18 patients with scleroderma and 94% of patients with systemic lupus erythematosus. The mean value of autoantibodies titre was higher in untreated hyperthyroid Graves' (1:84 000) and lowest in positive patients with autoimmune disease of non-thyroid origin (1:4000). The cross-reactivity of antimicrosomal antigen antibodies was below 10%; there was no influence of antithyroglobulin antibodies on the ELISA; and most of the autoantibodies react with plasma membrane antigens different from the TSH binding sites.


2021 ◽  
Vol 12 ◽  
Author(s):  
Bochao Liu ◽  
Ze Wu ◽  
Chaolan Liang ◽  
Jinhui Lu ◽  
Jinfeng Li ◽  
...  

Since December 2019, a novel coronavirus (SARS-CoV-2) has resulted in a global pandemic of coronavirus disease (COVID-19). Although viral nucleic acid test (NAT) has been applied predominantly to detect SARS-CoV-2 RNA for confirmation diagnosis of COVID-19, an urgent need for alternative, rapid, and sensitive immunoassays is required for primary screening of virus. In this study, we developed a smartphone-based nanozyme-linked immunosorbent assay (SP-NLISA) for detecting the specific nucleocapsid phosphoprotein (NP) of SARS-CoV-2 in 37 serum samples from 20 COVID-19 patients who were diagnosed by NAT previously. By using SP-NLISA, 28/37 (75.7%) serum samples were detected for NP antigens and no cross-reactivity with blood donors’ control samples collected from different areas of China. In a control assay using the conventional enzyme-linked immunosorbent assay (ELISA), only 7/37 (18.91%) serum samples were detected for NP antigens and no cross-reactivity with control samples. SP-NLISA could be used for rapid detection of SARS-CoV-2 NP antigen in primary screening of SARS-CoV-2 infected individuals.


Author(s):  
Khalid S. Alshallash Khalid S. Alshallash

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression


1996 ◽  
Vol 79 (2) ◽  
pp. 426-430 ◽  
Author(s):  
Touichi Tanaka ◽  
Hideharu Ikebuchi ◽  
Jun-Ichi Sawada ◽  
Mariko Okada ◽  
Yasumasa Kido

Abstract An easy, sensitive, competitive indirect enzyme- linked immunosorbent assay (CI-ELISA) for specti nomycin in chicken plasma was developed. Preparation of a spectinomycin-bovine serum albumin conjugate in which the hapten is linked to the carrier protein through the C-4 position is described. Antibodies raised against antigens in rabbits had excellent specificity for spectinomycin, exhibiting a cross-reactivity of 44.0% with dihydrospectinomy-cin and 13.8% with tetrahydrospectinomycin. No cross-reactivity was observed with other antibiotics. The detection limit of the CI-ELISA was 2 ng/mL (equivalent into 40 ng/mL undiluted chicken plasma) spectinomycin. Known amounts (0.1-100 μg/mL) of spectinomycin were added to chicken plasma and then analyzed. Average recoveries were 97-110%. This procedure may be used without prior extraction of samples.


2000 ◽  
Vol 7 (4) ◽  
pp. 652-657 ◽  
Author(s):  
Tomoko Tajima ◽  
Ning Zhi ◽  
Quan Lin ◽  
Yasuko Rikihisa ◽  
Harold W. Horowitz ◽  
...  

ABSTRACT Enzyme-linked immunosorbent assay (ELISA) for human granulocytic ehrlichiosis (HGE) using two different recombinant P44 proteins (rP44 and rP44-2hv) of the HGE agent as antigens was evaluated. Sera from a total of 72 healthy humans both from regions where HGE is nonendemic and regions where HGE is endemic were used as negative controls to determine the cutoff value for ELISA. Sera from a total of 14 patients (nine from whom the HGE agent was isolated and five who were HGE-PCR positive) were used as positive controls. One hundred nine sera from 72 patients in an area where HGE is endemic who were suspected of having HGE were examined by ELISA and indirect immunofluorescence assay (IFA). All IFA-negative sera were negative by both ELISAs. Of 39 sera that were IFA positive, 35 and 27 were positive by ELISA using rP44 and rP44-2hv, respectively, indicating that the use of rP44 is more sensitive. Western blot analysis of the four rP44-ELISA-negative IFA-positive sera using whole HGE agent as antigen suggests that these four sera were false IFA positive. There was no difference in results with or without the preabsorption of sera with Escherichia coli or with or without the cleavage of the fused protein derived from the vector. There was a significant positive correlation between IFA titers and optical densities of ELISAs. Four Ehrlichia chaffeensis-positive and 10 Borrelia burgdorferi-positive sera were negative by ELISA. However, twoBabesia microti-positive sera showed strong cross-reactivity to the fused vector protein, which was eliminated after cleavage of the protein. Thus, ELISA using rP44 nonfusion protein would provide a simple, specific, and objective HGE serologic test which can be easily automated.


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