PubMed HealthSearch

PubMed · 8660618

Enzyme-linked immunosorbent assay by image analysis using a charge-coupled device array detector.

Abstract

This paper describes a fluorescence enzyme-linked immunosorbent assay (ELISA) for the quantification of (+/-)-2-(2, 4-dichlorophen-oxy)propionic methyl ester (dichlorprop methyl ester). Antibodies for dichlorprop methyl ester were produced by immunizing rabbits with a conjugate of dichlorprop methyl ester with bovine serum albumin. Data acquisition on microtiter wells is performed by a spectrofluorometer through a fiber optic and by a charge-coupled device camera. A correlation was obtained between the image analysis data on ELISA and the data acquired by the spectrofluorometer. The results demonstrate that the fluorescence image analysis performed by the charge-coupled device detector is applicable to ELISA, and the analysis time, sensitivity, and precision of the ELISA procedure are compared to conventional fluorescence ELISA performed by the spectrofluorometer. The ELISA procedure was selective for structurally similar compounds or usually found in formulation pesticides. Concentrations for 50% displacement curves were dichlorprop, 83.59 microg/ml, and 2,4,5-T, 388.23 microg/ml; triclopyr, ioxynil, bentazone, and MCPA had no response.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

F G Sánchez, A N Díaz, J Lovillo. 1996-07-15. Enzyme-linked immunosorbent assay by image analysis using a charge-coupled device array detector.. https://doi.org/10.1006/abio.1996.0283

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Ecotoxicological responses of aquatic macrophytes to 2,4-D: A global synthesis of species sensitivity and ecological risk.

The widespread use of 2,4-dichlorophenoxyacetic acid (2,4-D) has raised concern about its persistence, mobility, and effects on non-target aquatic vegetation in freshwater ecosystems. Here, we provide a global synthesis of the ecotoxicological responses of aquatic macrophytes to 2,4-D based on a PRISMA-guided systematic review of 86 peer-reviewed studies published between 1947 and 2025. A consistent gradient of species-specific sensitivity was observed across macrophyte growth forms. The submerged species Myriophyllum spicatum showed high susceptibility, with EC₅₀ values of 0.04-0.182 mg/L and marked growth inhibition at low concentrations, whereas floating species such as Lemna minor and Pontederia crassipes were more tolerant, requiring higher concentrations (7.08 to >100 and 8.1 mg/L, respectively) to produce comparable effects. Importantly, this sensitivity ranking was consistent across laboratory and field experimental settings. These interspecific differences likely reflect variation in herbicide uptake, translocation, and detoxification capacity associated with growth form. The overlap between EC₅₀ values for M. spicatum and regulatory thresholds for 2,4-D in surface waters suggests that current limits may be insufficient to protect sensitive submerged macrophyte communities. Regarding remediation, L. minor and Salvinia natans emerged as the most promising candidates for phytoremediation, while P. crassipes showed limited capacity to reduce herbicide concentrations in water. Despite advances, no study directly compared oxidative stress biomarkers between submerged and floating species, representing a critical gap in understanding the biochemical basis of the sensitivity gradient. Overall, this synthesis highlights the need to account for taxon-dependent sensitivity when evaluating the ecological risks of 2,4-D and provides a basis for improving regulatory frameworks and management of herbicide contamination in freshwater ecosystems.

2,4-Dichlorophenoxyacetic Acid

TfdR, the LysR-type transcriptional activator, is responsible for the activation of the tfdCB operon of Pseudomonas putida 2, 4-dichlorophenoxyacetic acid degradative plasmid pEST4011.

In Pseudomonas putida EST4021, the tfdCB operon of plasmid pEST4011 encodes enzymes involved in 2,4-dichlorophenoxyacetic acid degradation. We have identified a gene, tfdR, important for the regulation of the tfdCB operon. Sequence analysis of the tfdR gene revealed an open reading frame with amino acid sequence similar to the LysR family of transcriptional activators. The tfdR gene is located upstream and transcribed divergently from the tfdCB operon. Utilizing primer extension analysis, the transcription initiation sites of the gene tfdR and the tfdCB operon were localized 85 (84)bp and 292bp upstream from the coding sequences of these genes, respectively. Multiple sequence analysis revealed that the genes tfdR, tfdC and tfdB of plasmid pEST4011 are most similar to the regulatory gene tfdR and the module 2 genes tfdC(II) and tfdB(II) of pJP4, respectively. The promoter-operator sequences of tfdR and its target tfdCB operon of pEST4011 have regions with highly conserved nucleotides characteristic for the catechol-subgroup LysR-type transcriptional activators. We showed that the pEST4011 tfdR gene product activates the expression of the tfdCB operon and the effector molecule for TfdR is 2,4-dichloro-cis,cis-muconate. Our data indicate that the structure and the mode of regulation of tfd genes are similar, despite the bacteria being isolated from different geographical regions.

2,4-Dichlorophenoxyacetic Acid

Shake-flask test for determination of biodegradation rates of (14)C-labeled chemicals at low concentrations in surface water systems.

A simple shake-flask surface water biodegradability die away test with (14)C-labeled chemicals added to microgram per liter concentrations (usually 1-100 microg/L) is described and evaluated. The aim was to provide information on biodegradation behavior and kinetic rates at environmental (low) concentrations in surface water systems. The basic principle of measurement was to determine evolved CO(2) indirectly from measurements of total organic activity in subsamples after stripping off their content of CO(2). Used with surface water alone the test simulates a pelagic environment and amended with sediments (0.1-1 dry weight/L) the test is intended to simulate a water environment with suspended solids (e.g., resuspended sediments). A protocol of the test used with the (14)C technique or with specific chemical analysis was recently developed by the International Organization for Standardization. Practical experience with the method is presented for a set of reference substances. These substances could be ranked in five groups of decreasing biodegradability: aniline>p-nitrophenol, 2, 4-dichlorophenoxyacetic acid>4-chloroaniline>maleic hydrazide, pentachlorophenol>atrazine. It was found that degradation rates and lag periods varied considerably among sampling sites and sometimes also among samples from the same site. No significant correlation could be established between degradation rates and microbial biomass estimates. Even small portions of added sediments greatly enhanced biodegradation of the absorbable compound pentachlorophenol, probably by providing sites for microbial attachment. Repeated tests indicated consistent degradation behavior for the readily degradable substances, whereas degradation sometimes stopped or failed with the more recalcitrant substances. A preadaptation step involving regular reinoculation with freshly collected surface water could, however, overcome the problems of false-negative results.

2,4-Dichlorophenoxyacetic Acid