Photodegradation of carbendazim sensitized by aromatic ketones

Carbendazim (1) is a benzimidazole extensively used as post-harvest fungicide on fruits and vegetables. The aim of the present work is to study the photodegradation of I sensitized by aromatic ketones, with special attention to mechanistic aspects and to the possible detoxification associated with photochemical treatment. Laser flash photolysis (LPF) lambda(exc) = 355 nm of xanthone (XA) and anthraquinone (AQ) was performed in MeCN solutions, in the presence of 1. A new transient absorbing at lambda(max) 500 and 320 nm was obtained and assigned to the semioxidized radical cation 1(+center dot). An exergonic thermodynamics for electron transfer quenching was confirmed by means of the Rehm-Weller equation. The same species was observed by direct LFP of 1 at 266 nm in polar solvents. Conversely, when a deoxygenated solution of 1 was submitted to LFP in cyclohexane the transient spectrum presented a band with maximum at 380 nm; it was assigned to the triplet excited state ((3)1*) on the basis of energy transfer to oxygen and beta-carotene. The photodegradation of 1 was achieved using XA and AQ as electron acceptors in a solar-simulator, in aerated aqueous medium; the reaction was faster with XA. Formation of a new photoproduct was initially observed; its structure was assigned as carbendazim N-C5 dimer (2). A balance of the total organic carbon (TOC) after prolonged irradiation indicated that mineralization does not occur to a significant extent, pointing to oxidative fragmentation of 1 and 2 to give a variety of low molecular weight products. To check whether the observed photodegradation of 1 results in a decreased toxicity, biological assays were performed using an established model based on the inhibition of mobility of Daphnia magna. The results demonstrate that photodegradation leads to a diminished toxicity, indicating that the photoproducts are less toxic than the parent compound. (C) 2013 Elsevier B.V. All rights reserved.Financial support from the MICINN (Grant: CTQ2010-19909) and the Generalitat Valenciana (Prometeo Program) is gratefully acknowledged.Jornet Olivé, MD.; Castillo López, MÁ.; Sabater Marco, C.; Tormos Faus, RE.; Miranda Alonso, MÁ. (2013). Photodegradation of carbendazim sensitized by aromatic ketones. Journal of Photochemistry and Photobiology A: Chemistry. 256:36-41. https://doi.org/10.1016/j.jphotochem.2013.02.004S364125

Unus pro omnibus, omnes pro uno: A novel, evidence-based, unifying theory for the pathogenesis of endometriosis

The theory of retrograde menstruation as aetiopathogenesis of endometriosis formulated by John Sampson in 1927 shows clear shortcomings: this does not explain why retrograde menstruation is a physiological process that affects 90% of women, while endometriosis occurs in only 10% of cases; it also does not explain the endometriotic foci distant from the pelvis, nor explains the cases of endometriosis in male patients. The immunological alterations of the peritoneal fluid explains the effects of disease, such as the inhibition of the physiological processes of cytolysis, but does not explain the cause. There is evidence to support the hypothesis that ectopic müllerian remnants of the endometrium, endocervix and endosalpinx are items from the genital ridge leaked during organogenesis. It is known that tissues derived from coelomatic epithelial and mesenchymal cells have the potential to metaplastically differentiate into epithelium and stroma. In addition, the phenotype of the ectopic endometrial cells is significantly different from those ectopic. There is scientific evidence that, during organogenesis, the genes of the Homeobox and Wingless family play a fundamental role in the differentiation of the ducts of Muller and development of the anatomical structure of the urogenital tract. We present here a hypothesis that deregulation of genes and the Wnt signaling pathway Wnt/β-catenin leads to aberrations and deregulation within the mesoderm, thus, may cause aberrant placement of stem cells. In addition, immune cells, adhesion molecules, extracellular matrix metalloproteinase and pro-inflammatory cytokines activate/alter peritoneal microenvironment, creating the conditions for differentiation, adhesion, proliferation and survival of ectopic endometrial cells

Laser-induced fluorescence with an OPO system. Part II: Direct determination of lead content in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF)

cited By 11International audienceFluorescence was induced by coupling a laser with an optical parametric oscillator (OPO) to develop an analytical method for the direct determination of lead content, at ultra-trace level, in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF). The optimization of atomization conditions, laser pulse energy, and mainly temporal parameters allowed us to reach a 3 fg detection limit (0.3 ng L-1) despite the low repetition rate of the device. The expected error on predicted concentrations of lead, at trace levels, in seawater was below 15%. © Springer-Verlag 2003

Laser–Induced Fluorescence Detection of Carbamates Traces in Water

International audienceThe absorption and fluorescence spectra of carbaryl (CB), carbofuran (CF) and carbendazim (MBC) have been studied. Fluorescence lifetime and fluorescence quantum yields are also reported as well as the influence of pH, solvent and presence of humic acids on fluorescence. The limit of detection (LD) of the three compounds has been measured by direct analysis by laser-induced fluorescence (LIF) using a pulsed YAG laser with an Optical Parametric Oscillator (OPO) as excitation source and an Intensified Charged Coupled Device (ICCD) camera for the fluorescence detection. Instrumental LD found for CB, for MBC and for CF are respectively 4, 50 and 1000 ng L(-1). In tap water, the LD obtained is 800 ng L(-1) for MBC and 20,000 ng L(-1) for CF. For CB, the use of a time shift between excitation and emission allows to reach a LD of 20 ng L(-1) in tap water

Direct determination of aluminum content in seawater by electrothermal atomization-laser excited atomic fluorescence

cited By 13International audienceThe development of an analytical method for the direct determination of ultra trace content of aluminum in seawater by electrothermal atomization-laser excited atomic fluorescence (ETA-LEAF) using a pulsed Nd:Yag laser associated with an optical parametric oscillator (OPO) and an intensified CCD (ICCD) camera is described. The good temporal reproducibility of the device and the fairly long lifetime of the selected Al radiation allowed optimization of the temporal parameters in the nanosecond range. After optimizing thermal and optical parameters, this potentiality allowed to reach a 100 fg detection limit (5 ng l-1). The method was developed within a multidisciplinary program involving chemical and physical applications, thereby demonstrating the versatility of the apparatus. © 2002 Elsevier Science B.V. All rights reserved

Spectroscopic Properties and Laser Induced Fluorescence Determination of Some Endocrine Disrupting Compounds

International audienceThis work presents spectroscopic properties of some Endocrine Disrupting Compounds (EDCs), frequently found in food and in natural water. Studied molecules belong to the groups of phenolic and phthalate EDCs. In a first part, we have examined their absorption and fluorescence properties. Fluorescence emission wavelengths are about 300 nm for phenolic compounds and 360 nm for phtalate compounds; main excitation wavelengths being comprised between 210 nm and 230 nm. Fluorescence lifetimes measured are short (about 4 ns) and the fluorescence quantum yield has been determined. In a second part, to avoid the time consuming solvent extraction step, an analytical application to evaluate the performance of a direct analysis by laser induced fluorescence spectroscopy of ECDs traces in tap water and in raw water is presented. Good detection limits have been obtained, i.e.: 0.35 µg.L−1 of chlorophenol in tap water, which are always lower than the reported Predictive Non Efficient Concentration (PNEC)

Identification of ZFPIP, a novel PBX1 interacting protein that interferes with the binding of HOX/PBX complex to DNA

Identification of ZFPIP, a novel PBX1 interacting protein that interferes with the binding of HOX/PBX complex to DNA. Spring Meeting of the British Society for Developmental Biology (BSDB

Direct Fluorescence Monitoring of Coal Organic Matter Released in Seawater

International audienceWhenever immersed in seawater after a collier accident, a fossil fuel such as coal could become a source of pollution to the marine environment. To study the effect of such a contamination, four coal samples from different origins were used. A first analysis on those coals enabled us to determine the content of polycyclic aromatic hydrocarbons. Seawater was then mixed with coal to study the organic matter released from coal into seawater. Fluorescence was used for its sensitivity to aromatic compounds, with the additional purpose of evaluating the relevance of using an immersed fluorescence probe to monitor water pollution. Excitation-emission matrices were recorded and the excitation-emission wavelength range corresponding to the highest fluorescence intensity was 230 nm/[370 nm; 420 nm]. The samples with coal happened to fluoresce more than the coal-free samples, the difference depending on the coal origin. The fluorescence intensity increased with coal mass, up to some limit. The particle size also influenced the fluorescence intensity, the finest particles releasing more fluorescing substances, due to their higher exchange surface. When seawater percolated through coal, the samples fluoresced highly at the beginning, and then the fluorescence intensity decreased and reached the seawater level. However, even with a 10 ns acquisition time shift, the fluorescence spectra were not specific enough to show the presence of PAHs in the samples, which were too diluted to be detected, whenever released from coal into seawater. The lifetimes of the seawater and of the coal samples were respectively 4.7 and 3.8 ns, indicating that the substances released from coal mainly consisted of short-lived fluorescing substances, such as natural humic or fulvic substances. Consequently, the presence of coal does not seem to be too detrimental to the marine environment, and a direct fluorescence probe could be used to monitor the seawater organic charge increase due to the immersion of coal in seawater

Identification of a new type of PBX1 partner that contains zinc finger motifs and inhibits the binding of HOXA9-PBX1 to DNA.

PBX1 belongs to the TALE-class of homeodomain protein and has a wide functional diversity during development. Indeed, PBX1 is required for haematopoiesis as well as for multiple developmental processes such as skeletal patterning and organogenesis. It has furthermore been shown that PBX1 functions as a HOX cofactor during development. More recent data suggest that PBX1 may act even more broadly by modulating the activity of non-homeodomain transcription factors. To better understand molecular mechanisms triggered by PBX1 during female genital tract development, we searched for additional PBX1 partners that might be involved in this process. Using a two hybrid screen, we identified a new PBX1 interacting protein containing several zinc finger motifs that we called ZFPIP for Zinc Finger PBX1 Interacting Protein. We demonstrated that ZFPIP is expressed in embryonic female genital tract but also in other PBX1 expression domains such as the developing head and the limb buds. We further showed that ZFPIP is able to bind physically and in vivo to PBX1 and moreover, that it prevents the binding of HOXA9/PBX complexes to their consensus DNA site. We suggest that ZFPIP is a new type of PBX1 partner that could participate in PBX1 function during several developmental pathways

Functionalized Phospholipid Molecular Platform: Use for Production of Cationic Fluorescent Lipids

International audienceFluorescent amphiphilic phospholipids (neutral or cationic) in which fluorescent probes are contained in the lipid domain were synthesized via phosphoramide intermediates possessing two distinct lipid chains. One of these lipid chains is ω-functionalized with an azide or alkyne group, and this is subsequently used to introduce a fluorescent probe by Huisgen cycloaddition. Five different fluorescent probes (naphthalimide, dansyl, fluoresceine, Nile red, and coumarin) were considered in this study. These neutral and cationic fluorescent lipids were included at a 1 % molar ratio with a selected cationic lipid (KLN47) to produce liposomal solutions that were characterized by dynamic light scattering and zeta potential measurements