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At least 19 recordsLinked to original sources
PubMed1975

The influence of non-cytotoxic concentrations of the herbicide 2,4-dichlorophenoxyacetic acid on the DNA synthesis in cultured vertebrate cells.

The influence of the herbicide 2,4-Dichlorophenoxyacetic acid on the growth of cultured chicken muscle cells was studied by observing morphological changes and by cytophotometric measurement of the DNA content of individual cells. DNA-synthesis curves were derived from the distribution of DNA values. No marked effects were observed at a concentration of 60 mug per liter. In contrast, doses of 600 mug per liter caused a loss in cell differentiation consisting of a partial lack of polar orientation, diminished formation of fibers, and an increase of the N/C ratio. The nuclear matrix of desoxyribonucleoprotein (DNP) changed to a more heteropycnotic structure. Isolated cell necroses were found after 44 hrs of exposure. When compared to the controls, the relative DNA synthesis time was found to be prolonged 1.5-fold. The number of cells in the G2 phase decreased during 44 hrs of exposure. It is concluded from these results that the dosedependent growth inhibition of 2,4-D on vertebrate cells in culture takes effect during DNA synthesis. The morphological changes of the nuclear structure suggests that 2,4-D directly affects the template activity of the DNP matrix.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2026

Occupational exposure to 2,4-dichlorophenoxyacetic acid (2,4-D) and associated oxidative and genomic biomarkers among soybean farmers: a cross-sectional study.

BACKGROUND: 2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely used for weed control in soybean cultivation. This study aimed to investigate hepatic and genetic damage biomarkers in farmers occupationally exposed to 2,4-D, widely used in soybean cultivation in southern Brazil (Rio Grande do Sul), in addition to estimate urinary 2,4-D concentrations as an indicator of recent exposure. METHODS: A cross-sectional study was conducted, including 54 occupationally exposed farmers and 51 non-exposed controls (organic farmers). RESULTS: Urinary 2,4-D was detected in 88.5% of the exposed group versus 25% of the controls (p&#xa0;<&#xa0;0.001). Creatine kinase (CK) was significantly elevated in the exposed group (p&#xa0;<&#xa0;0.05), suggesting possible muscle injury, while AST and ALT (classical liver enzymes) did not differ between groups. Oxidative stress markers showed a clear pattern of redox imbalance, with increased TBARS (p&#xa0;<&#xa0;0.001), increased CAT activity (p&#xa0;<&#xa0;0.001), and reduced SOD activity (p&#xa0;<&#xa0;0.001). Telomere length was significantly shorter in the exposed group (p&#xa0;=&#xa0;0.001). Use of personal protective equipment (PPE) was reported to be inadequate. CONCLUSION: Occupational exposure to 2,4-D is associated with systemic oxidative stress and telomere shortening, even in the absence of transaminase elevation. This points to early hepatocellular vulnerability mediated by oxidative mechanisms rather than overt cytolysis. The study emphasizes the need for continuous monitoring of populations chronically exposed to chlorophenoxy herbicides.

2,4-dichlorophenoxyacetic acid↗
PubMed1977

The influence of pH on the effects of 2,4-D (2,4-dichlorophenoxyacetic acid, Na salt) on Saccharomyces cerevisiae and Salmonella typhimurium.

The genetic effects of 2,4-D (2,4-dichlorophenoxyacetic acid, Na salt) have been investigated in cells of the yeast Saccharomyces cerevisiae and of the bacterium Salmonella typhimurium in experiments in vitro and in vivo. Experiments in vitro showed that the killing of both yeast and bacteria is dependent on the pH in the treatment solution of 2,4-D. A dose-dependent increase of the frequency of mitotic gene conversion and mitotic recombination in yeast was observed at pH 4.50 and 4.30. In experiments in vitro with two strains of Salmonella no significant increase of the number of revertants to prototrophy was obtained. The positive correlation between survival of cells and dissociation of 2,4-D in the pH region 2.8-5.0 indicates that the cells are unable to take up dissociated 2,4-D. Therefore the survival is high at a high pH when most 2,4-D is in dissociated form, and the survival is low at a relatively low pH when more of the 2,4-D is in its undissociated form. No genetic effects were induced by oral administration of tolerable doses of 2,4-D in host-mediated assays using mice as hosts and yeast or Salmonella as indicator cells.

2,4-Dichlorophenoxyacetic Acid↗
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 EC&#x2085;&#x2080; 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 EC&#x2085;&#x2080; 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↗
PubMed2026

Rapid Agrobacterium-mediated transformation and high-efficiency regeneration of finger millet (Eleusine coracana) for crop improvement.

Finger millet (Eleusine coracana) is a nutritionally important and climate-resilient cereal cultivated in rainfed regions of India and Eastern Africa, yet its genetic improvement has been limited by the lack of efficient and reproducible transformation systems. In this study, we developed a rapid and efficient Agrobacterium tumefaciens-mediated transformation and regeneration system using shoot apical meristem (SAM) explants, enabling direct, callus-free shoot organogenesis. Optimal regeneration and shoot elongation were achieved on Murashige and Skoog (MS) medium supplemented with 3.5&#xa0;mg L&#x207b;1 6-benzylaminopurine (BAP), 1.5&#xa0;mg L&#x207b;1 kinetin, 0.1&#xa0;mg L&#x207b;1 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.2&#xa0;mg L&#x207b;1 gibberellic acid (GA&#x2083;). Genotype-dependent responses were observed, with PR-202 requiring 2&#xa0;mg L&#x207b;1 AgNO3 to reduce phenolic browning, whereas VL-376 regenerated efficiently without AgNO3. Transformation efficiencies of 30-32% were achieved in PR-202 and VL-376, respectively, by optimising infection and co-cultivation conditions, including reduced MS salt strength and pre-incubation of Agrobacterium. Molecular analyses, including PCR and Southern blot hybridisation, confirmed stable T-DNA integration in independent lines, while segregation analysis of T&#x2081; progenies demonstrated Mendelian inheritance of the transgene. In addition, CRISPR/Cas9 constructs targeting EcCKX2 were successfully introduced via Agrobacterium, demonstrating the suitability of this system for genome engineering applications. Overall, this optimised SAM-based protocol provides a rapid (45-50&#xa0;days), efficient, and reproducible platform for stable genetic transformation in finger millet and establishes a strong foundation for transgenic research and future genome editing studies in this underutilized crop.

Eleusine↗
PubMed1978

Developmental restrictions on hormone modulated gene transcription. II. Hormone induced interactions of RNA polymerase with chromatin.

Chromatin-bound and soluble RNA polymerase subspecies have been isolated and fractionated by isoelectric focusing at various times (0, 6, 12 and 18 h) following auxin treatment of 4 day (responsive) and 8 day (unresponsive) soybean hypocotyls. Young 4 day seedlings displayed two well defined phases of auxin induced gene transcription. Phase I (6 h) evidenced the selective dissociation of many RNA polymerase subspecies from the chromatin complex which was accompanied by the retention of three class II enzymes. Phase II occurred after 12 h of treatment when the dissociated enzymes including some species which were soluble in the 0 h controls became re-associated with chromatin. These induced RNA polymerases may be responsible for the synthesis of auxin induced RNAs. In contrast, the unresponsive 8 day hypocotyl did not display two phases of auxin induction. Phase one, the dissociation of the chromatin bound enzymes, occurred at 12 h (compared to 6 h for the 4 day seedling) and was not followed by the later translocation of any soluble enzymes towards the chromatin complex. The results support earlier findings suggesting that the developmental "phasing out" of RNA polymerase subspecies limits the hormone induced growth response of this tissue and thus is regarded as an off switch for the transcription of such hormone controlled gene sequences.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1979

Treatment of severe 2,4-D and mecoprop intoxication with alkaline diuresis.

1 Self-poisoning with a selective weedkiller containing 2,4-D and mecoprop in a 39 year old man resulted in prolonged deep coma, pyrexia, hyperventilation, hypoxaemia, myotonia, skeletal muscle damage and electrocardiographic changes consistent with cardiomyopathy. 2 The admission plasma concentrations of 2,4-D and mecoprop were 400 and 751 microgram/ml respectively. The patient remained gravely ill with no signs of improvement for 2 days with supportive therapy and there was no fall in the 2,4-D level. 3 Alkaline diuresis greatly increased the renal clearance of 2,4-D, and there was a rapid fall in plasma concentration (T1/2 3.7 h) with corresponding clinical improvement. The effect on the elimination of mecoprop was similar, but less dramatic. 4 Forced alkaline diuresis may improve the otherwise very poor prognosis in severe intoxication with 2,4-D and related weedkillers.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1979

14C-most-probable-number method for enumeration of active heterotrophic microorganisms in natural waters.

A most-probable-number method using 14C-labeled substrates is described for the enumeration of aquatic populations of heterotrophic microorganisms. Natural populations of microorganisms are inoculated into dilution replicates prepared from the natural water from which the organisms originated. The natural water is supplemented with a 14C-labeled compound added so as to approximate a true environmental concentration. 14CO2 evolved by individual replicates is trapped in NaOH and counted by liquid scintillation techniques for use in scoring replicates as positive or negative. Positives (14CO2 evolution) are easily distinguished from negatives (no 14CO2 evolution). The results from a variety of environments using the 14CO2 procedure agreed well with previously described methods, in most instances. The 14C-most-probable-number method described here reduces handling procedures over previously described most-probable-number procedures using 14C-labeled substrates. It also appears to have advantages over other enumeration methods in its attempt to approximate natural conditions more closely.

2,4-Dichlorophenoxyacetic Acid↗