Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 232748

Myosin changes in experimental 2,4-dichlorophenoxyacetate myopathy.

A Muhlrad·M Friedman
View original source ↗Export metadata ↓

Abstract

Young rats treated with 10 to 14 daily injections of 2,4-dichlorophenoxyacetate (2,4-D) developed a myopathy mainly involving fast muscles. Myosin isolated from the gastrocnemius muscles of treated and normal control animals differed in several respects. The Ca2+- and Mg2+-mediated ATPases were higher in myopathic muscle myosin than in normals. Alkylation of thiols by N-ethylmaleimide (NEM) induced an increase of Ca2+-activated ATPase that was higher in normal than in myopathic myosin. Trinitrophenylation of reactive amino groups by 2,4,6-trinitrobenzene sulfonate (TBS) induced on increase in Mg2+-mediated ATPase in both preparations, but the increase was higher in normals. Although the heavy- and light-chain pattern was identical in normal and myopathic myosin, during storage at 0 degrees C the relative amount of myopathic L2 light chain decreased. Myosins fragmented either by limited proteolysis with trypsin and chymotrypsin or by specific cleavage at tryptophanyl and cysteinyl peptide bonds showed differences on sodium dodecylsulfate (SDS)-polyacrylamide-gel electrophoresis. The results indicate that there is a change in the heavy chains of myosin isolated from the gastrocnemius muscle in 2,4-D-induced rat myopathy.

Explore related subjects

2,4-Dichlorophenoxyacetic AcidAdenosine TriphosphatasesAnimalsCalcium-Transporting ATPasesElectrophoresis, Polyacrylamide GelFemaleMagnesiumMuscular DiseasesMyosinsRatsSodium-Potassium-Exchanging ATPaseJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A Muhlrad, M Friedman. Myosin changes in experimental 2,4-dichlorophenoxyacetate myopathy.. https://doi.org/10.1002/mus.880010606

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

KEEP EXPLORING

Related citations

PubMed2026

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↗
PubMed2007

Adsorption of 2,4-dichlorophenoxyacetic acid by an Andosol.

To identify the important soil components involved in 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption on Andosols, 2,4-D adsorption on a surface horizon of an Andosol was compared with that on hydrogen peroxide (H2O2)-treated (soil organic matter [SOM] was removed), acid-oxalate (OX)-treated (active metal hydroxides and SOM were removed), and dithionite-citrate-bicarbonate (DCB)-treated (free and active metal [hydr]oxides and SOM were removed) soil samples at equilibrium pHs ranging from 4 to 8. Although the untreated soil contained a large amount of organic C (71.9 g kg-1), removal of SOM had little effect on 2,4-D adsorption. Active surface hydroxyls, which were attached to the active and free metal (hydr)oxides and metal SOM complexes, were identified as the most important soil functional group for 2,4-D adsorption. The dominant mechanism of the 2,4-D adsorption was a ligand exchange reaction in which the carboxylic group of 2,4-D displaced the active surface hydroxyl associated with metals and formed a strong coordination bond between the 2,4-D molecule and soil solid phase. The ligand exchange reaction reasonably accounted for the selective adsorption of 2,4-D over Cl-, competitive adsorption of phosphate over 2,4-D, reduction in plant-growth-inhibitory activity of soil-adsorbed 2,4-D, and the high 2,4-D adsorption ability of Andosols. Although a humic acid purified from the soil did not adsorb 2,4-D, the presence of the humic acid increased 2,4-D adsorption on Al and Fe, probably by inhibiting the hydrolysis and polymerization of Al and Fe resulting in the preservation of available adsorption sites on these metals. The adsorption behavior of 2,4-D on soils could be a good index for predicting the adsorption behavior of other organic acids in soils.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2007

Activated sludge treatment of a xenobiotic with or without a biogenic substrate during start-up and shocks.

Lab-scale continuous flow activated sludge systems that were acclimated to 2,4-dichlorphenoxyacetic acid (2,4-D) under sole 2,4-D influent and without sludge wastage, were able to maintain successful 2,4-D treatment when both 2,4-D and a biogenic substrate were fed and the systems operated with finite mean cell residence times (theta(c)). When the systems were fed dual 2,4-D and biogenic substrates and operated with finite theta(c) from the start, treatment of 2,4-D fluctuated noticeably long after acclimation. At the reintroduction of 2,4-D after its absence from the influent for a period of time (2,4-D shock), the systems under both the sole and dual substrate conditions suffered similar treatment losses; the extent of treatment losses was related to the length of 2,4-D absence time. When shocked, systems with sole 2,4-D influent had a slight advantage over dual substrates by showing a faster recovery from shocks with the help of re-acclimation.

2,4-Dichlorophenoxyacetic Acid↗