The resistance of the yeast Saccharomyces cerevisiae to the biocide polyhexamethylene biguanide: involvement of cell wall integrity pathway and emerging role for YAP1

<p>Abstract</p> <p>Background</p> <p>Polyhexamethylene biguanide (PHMB) is an antiseptic polymer that is mainly used for cleaning hospitals and pools and combating <it>Acantamoeba </it>infection. Its fungicide activity was recently shown by its lethal effect on yeasts that contaminate the industrial ethanol process, and on the PE-2 strain of <it>Saccharomyces cerevisiae</it>, one of the main fermenting yeasts in Brazil. This pointed to the need to know the molecular mechanism that lay behind the cell resistance to this compound. In this study, we examined the factors involved in PHMB-cell interaction and the mechanisms that respond to the damage caused by this interaction. To achieve this, two research strategies were employed: the expression of some genes by RT-qPCR and the analysis of mutant strains.</p> <p>Results</p> <p>Cell Wall integrity (CWI) genes were induced in the PHMB-resistant <it>Saccharomyces cerevisiae </it>strain JP-1, although they are poorly expressed in the PHMB-sensitive <it>Saccharomyces cerevisiae </it>PE2 strain. This suggested that PHMB damages the glucan structure on the yeast cell wall. It was also confirmed by the observed sensitivity of the yeast deletion strains, <it>Δslg1, Δrom2, Δmkk2</it>, <it>Δslt2</it>, <it>Δknr4</it>, <it>Δswi4 </it>and <it>Δswi4</it>, which showed that the protein kinase C (PKC) regulatory mechanism is involved in the response and resistance to PHMB. The sensitivity of the <it>Δhog1 </it>mutant was also observed. Furthermore, the cytotoxicity assay and gene expression analysis showed that the part played by <it>YAP1 </it>and <it>CTT1 </it>genes in cell resistance to PHMB is unrelated to oxidative stress response. Thus, we suggested that Yap1p can play a role in cell wall maintenance by controlling the expression of the CWI genes.</p> <p>Conclusion</p> <p>The PHMB treatment of the yeast cells activates the PKC1/Slt2 (CWI) pathway. In addition, it is suggested that HOG1 and YAP1 can play a role in the regulation of CWI genes.</p

First Description of KPC-2-Producing Klebsiella oxytoca in Brazil

The present work reports the detection of the first case of nosocomial Klebsiella oxytoca producing class A carbapenemase KPC-2 in Brazil. the isolate KPN106 carried a 65-kb IncW-type plasmid that harbors the bla(KPC) gene and Tn4401b. Moreover, we detected the presence of a class 1 integron containing a new allele, arr-8, followed by a 5'-truncated dhfrIIIc gene. in view of the recent results, we emphasize the high variability of the bacterial and genetic hosts of this resistance determinant.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FACEPEPFA/UPEUniv Pernambuco, Inst Ciencias Biol, Lab Resistencia Microbiana, Recife, PE, BrazilUniv Fed Pernambuco, Dept Genet, Lab Genet Microrganismos, Recife, PE, BrazilUniversidade Federal de São Paulo, Lab Alerta, São Paulo, BrazilCPqAM Fiocruz, Ctr Pesquisa Aggeu Magalhaes, Recife, PE, BrazilUniversidade Federal de São Paulo, Lab Alerta, São Paulo, BrazilWeb of Scienc

Os testes não-paramétricos g e qui-quadrado e suas aproximações

In this paper we show from where became and the aproach of a alternative to the few published no-parametric test, knowed chis-quare in the literature as G test. By deduction, we research the origin of this statistics and the aproach of the statistics of chi-square that is used at the hypothesis tests.Neste trabalho é apresentada a procedência e a aproximação de um teste não-paramétrico alternativo ao teste do Qui-quadrado (x2), conhecido na literatura como teste G, mas pouco divulgado. Foi verificada a origem desta estatística através de deduções e também a aproximação a estatística do Qui-quadrado, utilizada nos testes de hipóteses

Validation of TerraClass mapping for the Municipality of Paragominas state of Pará

This work aims to evaluate the TerraClass mapping for the year 2014, in the municipality of Paragominas, State of Pará. The validation was made by comparing the mapping with the observations found in the field. Images of the Satétile Landsat-8, OLI sensor of the year 2014, path/row 222/062, 222/063, 223/062 and 223/063 were used to aid in the field. Using this data it was possible to analyze the main representative classes in the area, including agriculture, urban area, forest, clean pasture, dirty pasture, reforestation, regeneration with pasture and secondary vegetation. The secondary vegetation presented 2,198.16 km², clean pasture with 3,332.29 km², agriculture with 896.75 km² and the forest occupying 54.21% of the total area of Paragominas. The overall concordance index was 86%, corroborating the reliability of the mapping performed. The average error was 6% and the total value of discordance was of 14%. Concerning the secondary vegetation, pasture, agriculture, urban area and forest classes, they presented concordance higher to 50%, while regeneration with pasture and reforestation presented greater intensity of omission with 40,57% and 76,31% respectively. Inclusion errors were less than 40% for the secondary vegetation, pasture regeneration, clean pasture and dirty pasture classes. The field work was essential to validate and analyze the accuracy of the 2014 TerraClass Project for the studied region, which becomes important for the understanding of the dynamics of land use

Main and moderated effects of multimorbidity and depressive symptoms on cognition

Objective: Multimorbidity, or the occurrence of two or more chronic conditions, is a global challenge, with implications for mortality, morbidity, disability, and life quality. Psychiatric disorders are common among the chronic diseases that affect patients with multimorbidity. It is still not well understood whether psychiatric symptoms, especially depressive symptoms, moderate the effect of multimorbidity on cognition. Methods: We used a large (n=2,681) dataset to assess whether depressive symptomatology moderates the effect of multimorbidity on cognition using structural equation modelling. Results: It was found that the more depressive symptoms and chronic conditions, the worse the cognitive performance, and the higher the educational level, the better the cognitive performance. We found a significant but weak (0.009; p = 0.04) moderating effect. Conclusion: We have provided the first estimate of the moderating effect of depression on the relation between multimorbidity and cognition, which was small. Although this moderation has been implied by many previous studies, it was never previously estimated

Spinnability and characteristics of polyvinylidene fluoride (PVDF)-based bicomponent fibers with a carbon nanotube (CNT) modified polypropylene core for piezoelectric applications

Biodiesel production has received considerable attention in the recent past as a nonpolluting fuel. However, this assertion has been based on its biodegradability and reduction in exhaust emissions. Assessments of water and soil biodiesel pollution are still limited. Spill simulation with biodiesel and their diesel blends in soils were carried out, aiming at analyzing their cytotoxic and genotoxic potentials. While the cytotoxicity observed may be related to diesel contaminants, the genotoxic and mutagenic effects can be ascribed to biodiesel pollutants. Thus, taking into account that our data stressed harmful effects on organisms exposed to biodiesel-polluted soils, the designation of this biofuel as an environmental-friendly fuel should be carefully reviewed to assure environmental quality. (C) 2011 Elsevier B.V. All rights reserved

Subacute toxicology studies on the aqueous fraction of the ethanol extract of the leaves of Cissampelos sympodialis Eichl. (Menispermaceae) in dogs

Cissampelos sympodialis Eichl. (Menispermaceae) has been investigated about its botanical, chemical, pharmacological and toxicological aspects in our laboratory. Previous acute toxicology studies demonstrated that in dogs as well as in Wistar rats, 5 g/kg, p.o., and 2 g/kg, i.p. of the aqueous fraction of the ethanol extract of the leaves of Cissampelos sympodialis (AFL), induced a significant increase in the phosphatase alkaline and gama glutamil tranferase (GGT) levels, that were completely reversed in 15 days after interruption of AFL treatment. The aim of the present work was to investigate the subacute toxicology effects induced by AFL in dogs. We used the methods proposed by Portaria 116/96 of the Secretaria Nacional de Vigilância Sanitária, which regulates studies of toxicity for phytomedicines in Brazil. Daily administration (p.o.) of AFL, 45 mg/kg/day (5 times the dose used by human beings), during 4 weeks, was devoid of any effect on haematological (haemogram and platelets) and on blood biochemical parametes. In conclusion, the present study, using dogs, demonstrated that AFL, in a popularly used dose, by human beings, was devoid of any toxicological effect

Near-infrared spectroscopy of blood plasma with chemometrics towards HIV discrimination during pregnancy

Abstract: Prevention of mother-to-child transmission programs have been one of the hallmarks of success in the fight against HIV/AIDS. In Brazil, access to antiretroviral therapy (ART) during pregnancy has increased, leading to a reduction in new infections among children. Currently, lifelong ART is available to all pregnant, however yet challenges remain in eliminating mother-to-child transmission. In this paper, we focus on the role of near-infrared (NIR) spectroscopy to analyse blood plasma samples of pregnant women with HIV infection to differentiate pregnant women without HIV infection. Seventy-seven samples (39 HIV-infected patient and 38 healthy control samples) were analysed. Multivariate classification of resultant NIR spectra facilitated diagnostic segregation of both sample categories in a fast and non-destructive fashion, generating good accuracy, sensitivity and specificity. This method is simple and low-cost, and can be easily adapted to point-of-care screening, which can be essential to monitor pregnancy risks in remote locations or in the developing world. Therefore, it opens a new perspective to investigate vertical transmission (VT). The approach described here, can be useful for the identification and exploration of VT under various pathophysiological conditions of maternal HIV. These findings demonstrate, for the first time, the potential of NIR spectroscopy combined with multivariate analysis as a screening tool for fast and low-cost HIV detection

Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress

In this study, we used real-time quantitative PCR (RT-qPCR) to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC) and two involved in the degradation of plant cell wall components (pglA and pel) were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon) and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases