scholarly journals Effects of Chlorophenoxy Herbicides and Their Main Transformation Products on DNA Damage and Acetylcholinesterase Activity

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sofia Benfeito ◽  
Tiago Silva ◽  
Jorge Garrido ◽  
Paula B. Andrade ◽  
M. J. Sottomayor ◽  
...  
Keyword(s):  
Double Helix ◽  
Acetylcholinesterase Activity ◽  
Transformation Products ◽  
Transformation Product ◽  
Dna Interaction ◽  
Visible Absorption ◽  
Persistent Pesticide ◽  
Chlorophenoxy Herbicides ◽  
Pesticide Transformation Products ◽  
The Stability

Persistent pesticide transformation products (TPs) are increasingly being detected among different environmental compartments, including groundwater and surface water. However, there is no sufficient experimental data on their toxicological potential to assess the risk associated with TPs, even if their occurrence is known. In this study, the interaction of chlorophenoxy herbicides (MCPA, mecoprop, 2,4-D and dichlorprop) and their main transformation products with calf thymus DNA by UV-visible absorption spectroscopy has been assessed. Additionally, the toxicity of the chlorophenoxy herbicides and TPs was also assessed evaluating the inhibition of acetylcholinesterase activity. On the basis of the results found, it seems that AChE is not the main target of chlorophenoxy herbicides and their TPs. However, the results found showed that the transformation products displayed a higher inhibitory activity when compared with the parent herbicides. The results obtained in the DNA interaction studies showed, in general, a slight effect on the stability of the double helix. However, the data found for 4-chloro-2-methyl-6-nitrophenol suggest that this transformation product can interact with DNA through a noncovalent mode.

The effect of transformation products of the antioxidant BHT on the initial stages of thermo- and photo-oxidation of LDPE

1995 ◽  
Vol 73 (11) ◽  
pp. 1862-1868 ◽  
Author(s):  
J. Kovářová ◽  
J. Rotschová ◽  
O. Brede ◽  
M. Burgers
Keyword(s):  
Transformation Products ◽  
Transformation Product ◽  
Phenolic Antioxidants ◽  
Spectroscopy Data ◽  
Photo Degradation ◽  
Photo Oxidation ◽  
Tert Butyl ◽  
Dsc Studies ◽  
Stabilizing Effect ◽  
The Stability

The effect of individual transformation products of 2,6-di-tert-butyl-4-methylphenol (1, BHT), namely, 2,6-di-tert-butyl-4-hydroxy-2,5-cyclohexadienone (3), 2,6-di-tert-butyl-1,4-benzoquinone (4), and 3,5,3′,5′-tetra-tert-butylstilbenequinone (5), in the course of thermal- and photo-degradation of LDPE has been examined. Oxidative DSC studies combined with oxygen uptake measurements, IR spectroscopy data, and embrittlement tests proved to be sufficiently sensitive to detect differences in the stability of the above-mentioned samples. A comparative study revealed a pronounced stabilizing effect of 5 in LDPE thermooxidation at moderate temperatures (90–100 °C). The stabilizing action of BHT is due in part at least to its coloured transformation product. Keywords: LDPE, thermooxidation, photooxidation, transformation products of phenolic antioxidants.

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

scholarly journals Phase Transformation of Cr(VI)-Adsorbed Ferrihydrite at Different pH in The Presence of Mn(II): Fate of Mn(II) and Cr(VI)

2021 ◽  
Author(s):  
Zecong Ding ◽  
Fenglian Fu ◽  
Guangzhao Sun ◽  
Chujia Ye
Keyword(s):  
Phase Transformation ◽  
Heavy Metal Ions ◽  
Solid Phase ◽  
Transformation Products ◽  
Transformation Process ◽  
Toxic Heavy Metal ◽  
Chromium Vi ◽  
Initial Ph ◽  
The Stability ◽  
Mn Concentration

Abstract Ferrihydrite is an important sink for the toxic heavy metal ions, such as chromium(VI). As ferrihydrite is thermodynamically unstable and gradually transforms into hematite and goethite, the stability of Cr(VI)-adsorbed ferrihydrite is environmentally significant. This study investigated the phase transformation of Cr(VI)-adsorbed ferrihydrite at different pH in the presence of aqueous Mn(II), as well as the fate of Mn(II) and Cr(VI) in the transformation process of ferrihydrite. Among the ferrihydrite transformation products, hematite was dominant, and goethite was minor. The pre-adsorbed Cr(VI) inhibited the conversion of ferrihydrite to goethite at initial pH 3.0, whereas little amount of adsorbed Mn(II) favored the formation of goethite at initial pH 7.0. After the aging process, Cr species in solid phase existed primarily as Cr(III) in the presence of Mn(II) at initial pH 7.0 and 11.0. The aqueous Mn concentration was predominantly unchanged at initial pH 3.0, whereas the aqueous Mn(II) was adsorbed onto ferrihydrite or form Mn(OH)2 precipitates at initial pH 7.0 and 11.0, promoting the immobilization of Cr(VI). Moreover, the oxidation of Mn(II) occurred at initial pH 7.0 and 11.0, forming Mn(III/IV) (hydr)oxides.

scholarly journals Photocatalytic Degradation of Diclofenac by Hydroxyapatite–TiO2 Composite Material: Identification of Transformation Products and Assessment of Toxicity

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1779 ◽  
Author(s):  
Sapia Murgolo ◽  
Irina Moreira ◽  
Clara Piccirillo ◽  
Paula Castro ◽  
Gianrocco Ventrella ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Wastewater Treatment Plants ◽  
Transformation Products ◽  
Environmental Water ◽  
Transformation Product ◽  
Target Compound ◽  
Germination Inhibition ◽  
Potential Applicability ◽  
Environmental Water Matrices

Diclofenac (DCF) is one of the most detected pharmaceuticals in environmental water matrices and is known to be recalcitrant to conventional wastewater treatment plants. In this study, degradation of DCF was performed in water by photolysis and photocatalysis using a new synthetized photocatalyst based on hydroxyapatite and TiO2 (HApTi). A degradation of 95% of the target compound was achieved in 24 h by a photocatalytic treatment employing the HApTi catalyst in comparison to only 60% removal by the photolytic process. The investigation of photo-transformation products was performed by means of UPLC-QTOF/MS/MS, and for 14 detected compounds in samples collected during treatment with HApTi, the chemical structure was proposed. The determination of transformation product (TP) toxicity was performed by using different assays: Daphnia magna acute toxicity test, Toxi-ChromoTest, and Lactuca sativa and Solanum lycopersicum germination inhibition test. Overall, the toxicity of the samples obtained from the photocatalytic experiment with HApTi decreased at the end of the treatment, showing the potential applicability of the catalyst for the removal of diclofenac and the detoxification of water matrices.

Determination of pesticide transformation products: A review of extraction and detection methods

2009 ◽  
Vol 1216 (40) ◽  
pp. 6767-6788 ◽  
Author(s):  
J.L. Martínez Vidal ◽  
P. Plaza-Bolaños ◽  
R. Romero-González ◽  
A. Garrido Frenich
Keyword(s):  
Transformation Products ◽  
Detection Methods ◽  
Pesticide Transformation Products
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