Evaluation of work-related volatile organic compounds (VOCs) exposition in automotive painting cabins industrial cleanings

Automotive painting cabins are cleaned with several solvents, being great part of them mixtures of volatile organic compounds (VOCs), where the three xylene isomers are the most important constituents. To evaluate the work-related exposition of the cleaners that use these mixtures of solvents, xylenes have been determined in the working ambient air as well as its metabolite, o-m-p-methyl hippuric acid, has been analysed in urine to establish the dermal and respiratory exposition. This evaluation has been done in order to assess the occupational exposure to VOCs and to know the working conditions of the cleaners, but also to evaluate the effectiveness of personal protective equipment (PPE), the engineering control and the work practices.The xylenes have been chosen as indicators of exposition because they are the main components in the cleaning solvents used, with a level of concentration between 50% and 85%.The Xylenes have an occupational exposure limit (8 h TWA) of 50 ppm (221 mg/m3) and a short-term exposure limit (STEL) of 100 ppm (442 mg/m3). On the other hand, the biological exposure index (BEI) for xylenes is the sum of the total methyl hippuric acids in urine at the end of the work-shift, being the value 1500 mg/g creatinine.

Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide

To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods) and glutaredoxins (Grxs). The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

Blood shizonticidal activities of phenazines and naphthoquinoidal compounds against Plasmodium falciparum in vitro and in mice malaria studies

Due to the recent advances of atovaquone, a naphthoquinone, through clinical trials as treatment for malarial infection, 19 quinone derivatives with previously reported structures were also evaluated for blood schizonticide activity against the malaria parasite Plasmodium falciparum. These compounds include 2-hydroxy-3-methylamino naphthoquinones (2-9), lapachol (10), nor-lapachol (11), iso-lapachol (12), phthiocol (13) and phenazines (12-20). Their cytotoxicities were also evaluated against human hepatoma and normal monkey kidney cell lines. Compounds 2 and 5 showed the highest activity against P. falciparum chloroquine-resistant blood-stage parasites (clone W2), indicated by their low inhibitory concentration for 50% (IC50) of parasite growth. The therapeutic potential of the active compounds was evaluated according to the selectivity index, which is a ratio of the cytotoxicity minimum lethal dose which eliminates 50% of cells and the in vitro IC50. Naphthoquinones 2 and 5, with activities similar to the reference antimalarial chloroquine, were also active against malaria in mice and suppressed parasitaemia by more than 60% in contrast to compound 11 which was inactive. Based on their in vitro and in vivo activities, compounds 2 and 5 are considered promising molecules for antimalarial treatment and warrant further study.

Intestinal gluconeogenesis is a key factor for early metabolic changes after gastric bypass but not after gastric lap-band in mice.

Unlike the adjustable gastric banding procedure (AGB), Roux-en-Y gastric bypass surgery (RYGBP) in humans has an intriguing effect: a rapid and substantial control of type 2 diabetes mellitus (T2DM). We performed gastric lap-band (GLB) and entero-gastro anastomosis (EGA) procedures in C57Bl6 mice that were fed a high-fat diet. The EGA procedure specifically reduced food intake and increased insulin sensitivity as measured by endogenous glucose production. Intestinal gluconeogenesis increased after the EGA procedure, but not after gastric banding. All EGA effects were abolished in GLUT-2 knockout mice and in mice with portal vein denervation. We thus provide mechanistic evidence that the beneficial effects of the EGA procedure on food intake and glucose homeostasis involve intestinal gluconeogenesis and its detection via a GLUT-2 and hepatoportal sensor pathway.

Calculation of Franck-Condon factors including anharmonicity: simulation of the C2 H4+ X̃2B 3u←C2 H4X̃1 Ag band in the photoelectron spectrum of ethylene

Our new simple method for calculating accurate Franck-Condon factors including nondiagonal (i.e., mode-mode) anharmonic coupling is used to simulate the C2H4+X2B 3u←C2H4X̃1 Ag band in the photoelectron spectrum. An improved vibrational basis set truncation algorithm, which permits very efficient computations, is employed. Because the torsional mode is highly anharmonic it is separated from the other modes and treated exactly. All other modes are treated through the second-order perturbation theory. The perturbation-theory corrections are significant and lead to a good agreement with experiment, although the separability assumption for torsion causes the C2 D4 results to be not as good as those for C2 H4. A variational formulation to overcome this circumstance, and deal with large anharmonicities in general, is suggested

Chorioretinal lacuna in the amniotic band syndrome.

The malformations in the amniotic band syndrome (ABS) are due to entrapment of fetal parts by fibrous band in the amniotic sac. Limbs are most commonly affected followed by craniofacial defects in one third of patients. Ocular defects include corneal leukomas and lid colobomas often contiguous with facial clefts, strabismus, hypertelorism, and microphthalmos. Unilateral chorioretinal defects or lacunae are rare findings in the ABS. We report a female infant with such a lacunar defect along with central nervous abnormalities, and discuss the differential diagnosis and the embryopathic implications.

Estrogenic activity assessment of environmental chemicals using in vitro assays: identification of two new estrogenic compounds.

Environmental chemicals with estrogenic activities have been suggested to be associated with deleterious effects in animals and humans. To characterize estrogenic chemicals and their mechanisms of action, we established in vitro and cell culture assays that detect human estrogen receptor [alpha] (hER[alpha])-mediated estrogenicity. First, we assayed chemicals to determine their ability to modulate direct interaction between the hER[alpha] and the steroid receptor coactivator-1 (SRC-1) and in a competition binding assay to displace 17ss-estradiol (E(2)). Second, we tested the chemicals for estrogen-associated transcriptional activity in the yeast estrogen screen and in the estrogen-responsive MCF-7 human breast cancer cell line. The chemicals investigated in this study were o,p'-DDT (racemic mixture and enantiomers), nonylphenol mixture (NPm), and two poorly analyzed compounds in the environment, namely, tris-4-(chlorophenyl)methane (Tris-H) and tris-4-(chlorophenyl)methanol (Tris-OH). In both yeast and MCF-7 cells, we determined estrogenic activity via the estrogen receptor (ER) for o,p'-DDT, NPm, and for the very first time, Tris-H and Tris-OH. However, unlike estrogens, none of these xenobiotics seemed to be able to induce ER/SRC-1 interactions, most likely because the conformation of the activated receptor would not allow direct contacts with this coactivator. However, these compounds were able to inhibit [(3)H]-E(2) binding to hER, which reveals a direct interaction with the receptor. In conclusion, the test compounds are estrogen mimics, but their molecular mechanism of action appears to be different from that of the natural hormone as revealed by the receptor/coactivator interaction analysis.

Use of green fluorescent protein-based reporters to monitor balanced production of antifungal compounds in the biocontrol agent Pseudomonas fluorescens CHA0.

AIMS: To develop reporter constructs based on stable and unstable variants of the green fluorescent protein (GFP) for monitoring balanced production of antifungal compounds that are crucial for the capacity of the root-colonizing Pseudomonas fluorescens strain CHA0 to control plant diseases caused by soil-borne pathogenic fungi. METHODS AND RESULTS: Pseudomonas fluorescens CHA0 produces the three antifungal metabolites 2,4-diacetylphloroglucinol (DAPG), pyoluteorin (PLT) and pyrrolnitrin (PRN). The gfp[mut3] and gfp[AAV] reporter genes were fused to the promoter regions of the DAPG, PLT and PRN biosynthetic genes. The reporter fusions were then used to follow the kinetics of expression of the three antifungal metabolites in a microplate assay. DAPG and PLT were found to display an inverse relationship in which each metabolite activates its own biosynthesis while repressing the synthesis of the other metabolite. PRN appears not to be involved in this balance. However, the microbial and plant phenolic metabolite salicylate was found to interfere with the expression of both DAPG and PLT. CONCLUSIONS: The results obtained provide evidence that P. fluorescens CHA0 may keep the antifungal compounds DAPG and PLT at a fine-tuned balance that can be affected by certain microbial and plant phenolics. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, the present study is the first to use stable and unstable GFP variants to study antibiotic gene expression in a biocontrol pseudomonad. The developed reporter fusions will be a highly valuable tool to study in situ expression of this bacterial biocontrol trait on plant roots, i.e. at the site of pathogen suppression.

Transcriptional profiling of Gram-positive Arthrobacter in the phyllosphere: induction of pollutant degradation genes by natural plant phenolic compounds.

Arthrobacter chlorophenolicus A6 is a Gram-positive, 4-chlorophenol-degrading soil bacterium that was recently shown to be an effective colonizer of plant leaf surfaces. The genetic basis for this phyllosphere competency is unknown. In this paper, we describe the genome-wide expression profile of A.chlorophenolicus on leaves of common bean (Phaseolus vulgaris) compared with growth on agar surfaces. In phyllosphere-grown cells, we found elevated expression of several genes known to contribute to epiphytic fitness, for example those involved in nutrient acquisition, attachment, stress response and horizontal gene transfer. A surprising result was the leaf-induced expression of a subset of the so-called cph genes for the degradation of 4-chlorophenol. This subset encodes the conversion of the phenolic compound hydroquinone to 3-oxoadipate, and was shown to be induced not only by 4-chlorophenol but also hydroquinone, its glycosylated derivative arbutin, and phenol. Small amounts of hydroquinone, but not arbutin or phenol, were detected in leaf surface washes of P.vulgaris by gas chromatography-mass spectrometry. Our findings illustrate the utility of genomics approaches for exploration and improved understanding of a microbial habitat. Also, they highlight the potential for phyllosphere-based priming of bacteria to stimulate pollutant degradation, which holds promise for the application of phylloremediation.

Estimation of surface roughness in a semiarid region from C-band ERS-1 synthetic aperture radar data

In this study, we investigated the feasibility of using the C-band European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) data to estimate surface soil roughness in a semiarid rangeland. Radar backscattering coefficients were extracted from a dry and a wet season SAR image and were compared with 47 in situ soil roughness measurements obtained in the rocky soils of the Walnut Gulch Experimental Watershed, southeastern Arizona, USA. Both the dry and the wet season SAR data showed exponential relationships with root mean square (RMS) height measurements. The dry C-band ERS-1 SAR data were strongly correlated (R² = 0.80), while the wet season SAR data have somewhat higher secondary variation (R² = 0.59). This lower correlation was probably provoked by the stronger influence of soil moisture, which may not be negligible in the wet season SAR data. We concluded that the single configuration C-band SAR data is useful to estimate surface roughness of rocky soils in a semiarid rangeland.

Activity of phosphorus of synthetic Fe-K-P compounds in superphosphate fertilizers as affected by pH and ionic strength

The concentration of orthophosphate ions released from Fe-K-P compounds (Fe3KH8(PO4)6 .6H2O and Fe3KH14(PO4)8 .4H2O) present in superphosphates increases with pH, which initially suggests that the agronomic effectiveness of P fertilizers containing high amounts of these compounds would also increase with soil pH but studies considering activity, instead of concentration, are necessary. With this purpose, both compounds were synthesized under laboratory conditions, characterized by elemental chemical analysis, optical microscopy, X ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and used in a solubility study. Solutions of 0.01, 0.05 and 0.1 mol L-1 NaCl with pH adjusted to 3.0, 4.0, 5.0, 5.5, 6.0, 6.5, 7.0 and 7.5 were prepared for the solubility study of H8-syn, H14-syn and a phosphate rock (PR) from Brazil. The orthophosphate activity as H2PO4- and HPO4(2-) was calculated in each situation as related to pH and ionic strength using software MINTEQ. The remaining precipitates after equilibrium were chemically analyzed and subjected to X ray, SEM and EDS. Results of chemical analysis and instrumental techniques confirmed the preparation method. The activity of orthophosphate ions of both compounds tended to decrease under increasing pH and/or ionic strength of the solution, which in turn suggests that an increase in the solution pH does not necessarily promote an increase in the P bioavailability for plant uptake. This can be important when evaluating agronomic data of P fertilizers with high contents of these two Fe-K-P compounds.

Production of fungal volatile organic compounds in bedding materials

Selostus: Haihtuvien orgaanisten yhdisteiden muodostuminen kuivikkeissa

Estudio de la reaccion de sulfurizacion de precursores Cu/In para la formacion de capas delgadas policristalinas de CuInS2 para celulas solares

En este trabajo se presenta un estudio detallado de los procesos implicados en la sulfurización de capas metálicas de Cu-In para la fabricación de células solares de CuInS2. Con este objeto, se ha desarrollado un experimento de sulfurización parcial de las capas, que han sido sometidas posteriormente a un tratamiento de selenización. El estudio de estas estructuras mediante Espectroscopía Raman y Espectroscopía de Electrones Auger (AES) ha permitido conocer algunos de los detalles de la reacción química, en concreto la identificación del frente de crecimiento de la reacción de sulfurización. Paralelamente, se ha desarrollado un sistema experimental que ha hecho posible investigar in-situ la reacción de sulfurización por Espectroscopía Raman, lo cual ha permitido un seguimiento preciso de la evolución estructural del material durante el proceso. Los resultados experimentales demuestran que la reacción de sulfurización se inicia en la superficie de la capa, dando lugar a la formación de CuInS2, coexistiendo dos estructuras cristalinas polimórficas (calcopirita y orden catiónico CuAu). Posteriormente la reacción química continúa asistida por la difusión de los metales hacia la superficie, que reaccionan con la atmósfera de azufre, de forma simultánea se produce una transformación de la fase CuAu del compuesto en la estructura calcopirita.