SUMMARYTwo monoclonal antibodies (M-Ab) specific for different epitopes on particles of soybean mosaic virus (SMV) were used in a double-antibody sandwich ELISA (M-Ab ELISA). The non-isotopic immunoassay, which used a biotinylated second antibody and an avidin-alkaline phosphatase detection system to detect SMV in soybean seed extracts, was compared with a polyclonal antibody-based solid-phase radioimmunoassay (SPRIA). M-Ab ELISA detected less than l0 ng of SMV/ml and was more sensitive than the SPRIA which detected 25 ng SMV/ml. Furthermore, M-Ab. ELISA required less than 36 h for seed sample assays and only 5.5 h for assays involving purified virus, whereas SPRIA required 3 or 4 days. When seeds from 33 field plots, in which 0~, 30~ and 50~o of the soybean plants had been inoculated with SMV, were assayed by both systems, results of the two tests correlated for 31 of 33 (94~) seed samples. This suggests that dual-site biotin-avidin M-Ab ELISA systems have potential utility for routine screening of seed samples.
SUMMARYHybridomas secreting monoclonal antibodies against three isolates of barley yellow dwarf virus (BYDV) were established. Two monoclonal antibody preparations were generated against the MAV isolate, one against RPV and six against P-PAV. None of the monoclonal antibody preparations reacted with healthy host components. Reactions of monoclonal antibodies, or unlabelled polyclonal antisera, in an indirect enzyme-linked immunosorbent assay (ELISA) indicated that all three virus isolates share a common epitope. BYDV particles dissociated when incubated in carbonatebicarbonate coating buffer at pH 9.6 but could be stabilized by prior dialysis against 2% formaldehyde or 2% glutaraldehyde. In indirect ELISA, unlabelled polyclonal antisera bound to both stabilized and dissociated particles of homologous and heterologous BYDV isolates. However, conjugated polyclonal antisera were incapable of binding to dissociated particles or to stabilized particles of heterologous isolates. Experiments with monoclonal antibodies in a competition ELISA indicated the presence of at least two epitopes on the coat protein of P-PAV.
Uracil DNA glycosylases are DNA repair enzymes present in virtually every organism. These enzymes function by excising from DNA uracil residues resulting from either misincorporation of dUMP residues by a DNA polymerase or deamination of cytosine. Recently, the enzyme has been exploited in PCRs as a means for controlling carryover contamination from previously amplified DNA. When the enzyme is used in amplifications of Borrelia burgdorferi target sequences, we have observed an enhancement in signal detected by a microwell plate DNA hybridization assay. This increase in signal is dependent upon the length of the target, is titratable with enzyme concentration, and has been observed with amplifications performed with both symmetric and asymmetric PCR profiles. The enhancement is shown to occur at the level of the target genomic DNA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.