Electrochemical oxidation of the herbicide tebuthiuron using DSA®-type electrode

Tebuthiuron (TBH) is a herbicide widely used in different cultures and known for its toxic effects. Electrochemical methods are promising for removing pollutants such as pesticides. This study showed the degradation of TBH using a DSA® anode operated at current densities of 50 to 200 mA cm-2. Removal presented pseudo-first order kinetics while high-pressure liquid chromatography (UV detection) showed two peaks, ascribed to degradation intermediates. The maximum percentage of total organic carbon removed was 12.9%. Ion chromatography revealed that higher concentrations of nitrate and nitrite ions formed with increasing current density

Pathogenicity index, production of hemolysin and serogroup of samples of Escherichia coli isolated from commercial layng hens

Este estudo avaliou o índice de patogenicidade, a produção de hemolisina e a determinação de sorogrupos de cepas de Escherichia coli isoladas de fígado de aves de postura comercial com um dia de idade. Para este estudo, foram analisados 32 lotes, dos quais 15 foram positivos para o\ud isolamento de E. coli no fígado, totalizando vinte e quatro amostras. A patogenicidade dos isolados foi determinada por inoculação no saco aéreo de pintinhos e classificada como alta, intermediária, baixa ou não-patogênica. Os sorogrupos foram identificados utilizando um conjunto de antissoros anti-O (O1 a O180). A produção de hemolisina foi determinada por semeadura em ágar sangue de galinha (8%) e em placas de ágar sangue de carneiro (8%). Do total de amostras estudadas, 17 (70,83%) foram classificadas como não patogênica, 6 (25%) como de baixa patogenicidade e 1 (4,17%) de alta patogenicidade. Foram identificados 14 sorogrupos diferentes: O1, O2, O5, O8, O15, O18, O22, O36, O64, O70, O75, O115, O132, O141. Cinco cepas não tiveram o sorogrupo identificado. Com relação ao teste de produção de hemolisina, todas as cepas foram consideradas negativas, tanto para o teste realizado com ágar sangue de galinha quanto para o de carneiro. Os resultados obtidos neste estudo demonstram a importância de se identificar as cepas prevalentes de E. coli nas diferentes regiões produtoras, podendo ser utilizados em estudos epidemiológicos.This work evaluated the index of pathogenicity, the production of hemolysin and determination of serogroups in Escherichia coli strains isolated from liver of commercial laying hens with one day of age. Thirtytwo lots were analyzed, of which 15 were positive for the isolation of E. coli in the liver, for a total of 24 samples. The pathogenicity in one-day-old chicks was determined by inoculation in air sac and was classified as high, intermediate or low pathogenicity, or non-pathogenic. Serogroups were identified using a set of anti-O antisera (O1 to O180). The production of hemolysin was determined by plating on chicken blood agar (8%) and sheep blood agar (8%). Of the samples studied, 17 (70.83%) were classified as non-pathogenic, 6 (25%) as low pathogenicity and 1 (4.17%) as high pathogenicity. Fourteen different serogroups were identified: O1, O2, O5, O8, O15, O18, O22, O36, O64, O70, O75, O115, O132 and O141, while 5 samples were non-typable. Regarding the test for production of hemolysin, all strains were considered negative for both the test performed with chicken blood agar and that with sheep blood agar. The results of this study demonstrate the importance of identifying the prevalent strains of E. coli in different producing regions, as this information can be used in epidemiological studie

Iron, copper and manganese complexes with in vitro superoxide dismutase and/or catalase activities that keep Saccharomyces cerevisiae cells alive under severe oxidative stress

Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPCINOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes. These compounds were evaluated as SOD and CAT mimetics. The manganese and iron compounds showed both SOD and CAT activities, while copper showed only SOD activity. The copper and manganese in vitro SOD activities are very similar (IC50 similar to 0.4 mu mol dm(-3)) and about 70-fold higher than those of iron. The manganese compound showed CAT activity higher than that of the iron species. Analyzing their capacity to protect Saccharomyces cerevisiae cells against oxidative stress (H2O2 and the O-2(center dot-) radical), we observed that all compounds act as antioxidants, increasing the resistance of yeast cells mainly due to a reduction of lipid oxidation. Especially for the iron compound, the data indicate complete protection when wild-type cells were exposed to H2O2 or O-2(center dot-) species. Interestingly, these compounds also compensate for both superoxide dismutase and catalase deficiencies; their antioxidant activity is metal ion dependent, in the order iron(III) > copper(II) > manganese(II). The protection mechanism employed by the complexes proved to be independent of the activation of transcription factors (such as Yap1, Hsf1, Msn2/Msn4) and protein synthesis. There is no direct relation between the in vitro and the in vivo antioxidant activities. (C) 2014 Elsevier Inc. All rights reserved

Eficiência de síntese microbiana, pH e concentrações ruminais de amônia em novilhos F1 Limousin x Nelore alimentados com dietas contendo cinco níveis de concentrado

Conduziu-se um ensaio com o objetivo de avaliar os efeitos de níveis de concentrado nas rações sobre a eficiência de síntese microbiana, o balanço de compostos nitrogenados, a concentração de amônia e o pH do fluido ruminal e a taxa de passagem da digesta ruminal. Foram utilizados cinco novilhos F1 Limousin x Nelore fistulados no rúmen, abomaso e íleo, alimentados à vontade com dietas que continham 25,0; 37,5; 50,0; 62,5; e 75,0% de concentrados e distribuídos em delineamento quadrado latino 5 x 5. As concentrações de amônia e o pH ruminal foram determinados em amostras de fluido ruminal coletadas imediatamente antes do fornecimento das rações e às 2, 4, 6, e 8 horas após. A taxa de passagem foi determinada pelo modelo unicompartimental utilizando-se o óxido crômico como indicador. A eficiência de síntese microbiana, expressa de diferentes formas, não foi influenciada pelo uso de concentrado, obtendo-se valores médios de 35,17 g Nmic/kg MODR, 33,01 g Nmic/kg CHODR e 355,66 g MSmic/kg CHODR. As concentrações máximas de amônia, para todos os tratamentos, ocorreram 2,92 horas após o fornecimento da ração. O pH do fluido ruminal decresceu linearmente com os níveis de concentrado e os tempos de coleta. As taxas de passagem de 0,065; 0,081; 0,064; 0,049; e 0,046.h-1 foram verificadas para os tratamentos com 25,0; 37,5; 50,0; 62,5; e 75,0% de concentrado, respectivamente. A adição de concentrado nas rações reduziu o pH e não alterou a eficiência microbiana.A trial was conducted to evaluate the effects of five concentrate levels in the diet on the efficiency of microbial synthesis, balance of nitrogen compounds, ammonia concentrate and pH ruminal fluid. Five rumen, abomasum and ileum fistulated F1 Limousin x Nellore bulls were full fed diets containing 25.0, 37.5, 50.0, 62.5, and 75.0% of concentrate and allotted to a 5 x 5 latin square design. The ammonia concentrations and ruminal pH were determined in ruminal fluid samples collected right after the diets supply and 2, 4, 6, and 8 hours after. The unicompartimental model using chromic oxide as marker determined the passage rate. The efficiency of microbial synthesis, expressed by different forms, was not influenced by the use of concentrate, obtaining average values of 35.17 g Nmic/kg MODR, 33.01 g Nmic/kg CHODR, and 355.66 g MSmic/kg CHODR. The maximum ammonia concentrations, for all treatments, were 2.92 hours after the diet supply. The ruminal pH fluid linearly decreased with the concentrate levels and the collection times. The passage rates of .065, .081, .064, .049, and .046.h-1 were verified for the treatments with 25.0, 37.5, 50.0, 62.5, and 75.0% of concentrate, respectively. The addition of concentrate in the diets reduced the pH and did not alter the microbial efficiency

Cell-Free Antigens from Paracoccidioides brasiliensis Drive IL-4 Production and Increase the Severity of Paracoccidioidomycosis

The thermally dimorphic fungus Paracoccidioides brasiliensis (Pb) is the causative agent of paracoccidioidomycosis (PCM), one of the most frequent systemic mycosis that affects the rural population in Latin America. PCM is characterized by a chronic inflammatory granulomatous reaction, which is consequence of a Th1-mediated adaptive immune response. In the present study we investigated the mechanisms involved in the immunoregulation triggered after a prior contact with cell-free antigens (CFA) during a murine model of PCM. The results showed that the inoculation of CFA prior to the infection resulted in disorganized granulomatous lesions and increased fungal replication in the lungs, liver and spleen, that paralleled with the higher levels of IL-4 when compared with the control group. The role of IL-4 in facilitating the fungal growth was demonstrated in IL-4-deficient- and neutralizing anti-IL-4 mAb-treated mice. The injection of CFA did not affect the fungal growth in these mice, which, in fact, exhibited a significant diminished amount of fungus in the tissues and smaller granulomas. Considering that in vivo anti-IL-4-application started one week after the CFA-inoculum, it implicates that IL-4-CFA-induced is responsible by the mediation of the observed unresponsiveness. Further, the characterization of CFA indicated that a proteic fraction is required for triggering the immunosuppressive mechanisms, while glycosylation or glycosphingolipids moieties are not. Taken together, our data suggest that the prior contact with soluble Pb antigens leads to severe PCM in an IL-4 dependent manner

EFFECTS OF VITAMIN C SUPPLEMENTATION ON THE CHRONIC PHASE OF CHAGAS DISEASE

Introduction: In order to examine the effectiveness of vitamin C (ascorbic acid) in combating the oxidative insult caused by Trypanosoma cruzi during the development of the chronic phase of Chagas disease, Swiss mice were infected intraperitoneally with 5.0 × 104 trypomastigotes of T. cruzi QM1strain. Methods: Mice were given supplements of two different doses of vitamin C for 180 days. Levels of lipid oxidation (as indicated by thiobarbituric acid reactive substances-TBARS), total peroxide, vitamin C, and reduced glutathione were measured in the plasma, TBARS, total peroxide and vitamin C were measured in the myocardium and histopathologic analysis was undertaken in heart, colon and skeletal muscle. Results: Animals that received a dose equivalent to 500 mg of vitamin C daily showed increased production of ROS in plasma and myocardium and a greater degree of inflammation and necrosis in skeletal muscles than those that received a lower dose or no vitamin C whatsoever. Conclusion: Although some research has shown the antioxidant effect of vitamin C, the results showed that animals subject to a 500 mg dose of vitamin C showed greater tissue damage in the chronic phase of Chagas disease, probably due to the paradoxical actions of the substance, which in this pathology, will have acted as a pro-oxidant or pro-inflammatory